Circalittoral Lophelia reefs

04-07-2005
Researched byFrances Perry & Dr Harvey Tyler-Walters Refereed byDr Jason Hall-Spencer, Dr Alex Rogers, Prof. Paul Tyler & Dr Murray Roberts
EUNIS CodeA5.631 EUNIS NameCircalittoral Lophelia pertusa reefs

Summary

UK and Ireland classification

EUNIS 2008A5.631Circalittoral Lophelia pertusa reefs
EUNIS 2006A5.631Circalittoral Lophelia pertusa reefs
JNCC 2004SS.SBR.Crl.LopLophelia reefs
1997 BiotopeCOR.COR.LopLophelia reefs

Description

The cold-water coral Lophelia pertusa forms patches of bushy growths composed of a network of anastomosing branches that grow into thickets, coppices and eventually reefs under favourable conditions. The morphology and size of reefs are highly variable but reefs may be circular, dome-shaped or elongate, forming distinct patches or arranged in lines of 'islands' along the edges of the continental shelf, sea mounts, offshore banks and other raised sea bed features. Reefs may be composed of coral thickets 10 -50 m across and several metres high, mounds of 50 -500 m in diameter and 2 -33 m high, or through growth and/or fusion of nearby patches, form large elongate coral banks of up to 5 km in length and I km wide, reaching heights of ca 200 m and cover several square kilometres, depending on local conditions. Reefs of the coral Lophelia pertusa, typically support a range of other biota. Lophelia reefs are generally found in areas of elevated current. The coral provides a 3 dimensional structure and a variety of microhabitats that provide shelter and a surface of attachment for other species. In the Sula Ridge Norway, the coral grows in an iceberg furrow forming a coral bank 13 km in length, 300 m wide and 45 m high. Although Lophelia pertusa dominates, other cold-water corals may also occur, e.g. Madrepora oculata, Desmophyllum cristagalli, Dendrophyllia cornigera, Enallopsammia rostata and Solensmilia variabilis. The reef supports a species rich assemblage of invertebrates, especially suspension feeders such as foraminiferans, sponges, hydroids, gorgonians  (Paragorgia arborea, Paramuricea placomus, Primnoa resedaeformis). Lophelia pertusa may also support other corals (Madrepora oculata and Solenosmilia variabilis), polychaetes, bryozoans, brachiopods, asteroids, ophiuroids, holothurians, ascidians, squat lobsters (Munida sarsi) and bivalves may also be present. These organisms have all been recorded within and among the corals (Wilson, 1979; Mortensen et al., 1995). Mobile species present include the redfish (Sebastes viviparous and Sebastes marinus), Ling (Molva molva) and tusk (Brosme brosme) (Husebo et al., 2002). Relatively few species have so far been shown to be closely associated with Lophelia pertusa, for example, eunicid polychaetes, especially Eunice norvegica, and brittlestars, especially Ophiocantha species. The associated community requires further study. The xenophyophore Syringammina fragilissima (a giant protozoan growing up to 20 cm in diameter) occurs at markedly increased densities in downstream 'tails' of the some Lophelia mounds. [NB biotope description composed by author.]

Recorded distribution in Britain and Ireland

Reefs of Lophelia pertusa have been recorded on raised offshore seabed features from the Shetland-Faroe Basin, Rockall Bank and Rockall Trough, Anton Dohrn Seamount, Rosemary Bank, Hatton Bank, Bill Bailey's Bank, and the Wyville-Thomson Ridge in the north Atlantic off Britain, and in the Porcupine Seabight and Porcupine Basin off west Ireland. The map shows the recorded distribution of Lophelia pertusa, including isolated colonies as well as reefs.

Depth range

50-100 m

Additional information

The ecology of Lophelia pertusa (henceforth Lophelia) reefs is poorly studied and the biology or Lophelia poorly known. The following review is based primarily on the detailed review of Lophelia pertusa by Rogers (1999) with additional material from more recent studies. The author is grateful to the referees for their helpful comments and for highlighting additional information and recent findings.

Listed By

Further information sources

Search on:

JNCC

Habitat review

Ecology

Ecological and functional relationships

Rogers (1999) stated that the ecology of Lophelia pertusa reefs was poorly understood and remained largely un-investigated. The following information is inferred from a few studies of the fauna of Lophelia reefs in nature and aquarium studies (Jensen & Frederiksen, 1992; Rogers, 1999; Mortensen, 2001). Although the major groups of organisms are probably similar, the exact species present will vary with location.
  • Lophelia pertusa and other cold-water corals provide hard substrata for attachment of other epifaunal organisms, in the form of living and dead coral and coral fragments. The dense bushy growth of Lophelia locally modifies the environmental conditions (e.g. water flow) and provides a wide variety of niches for colonization by other species. Therefore, Lophelia may be regarded as an 'autogenic engineer' (Rogers, 1999) or key structural species.
  • Lophelia is a passive suspension feeder or passive carnivore, which has been observed to take zooplankton such as calanoid copepods and cumaceans in nature, and to take live zooplankton such as chaetognaths, small crustaceans (ca 1 mm e.g. copepods), and larger species such as krill ca 2 cm in length in aquaria (Mortensen, 2001; Mortensen et al., 2001). Mortensen (2001) demonstrated that Lophelia could also take a variety of foods, including dead food particles of krill, shrimp, herring and squid, and was able to reject unsuitable material including sediment. Mortensen (2001) concluded that Lophelia could utilize small organic particulates as food as well as live zooplankton. It probably also feeds on small invertebrates crawling over the coral surface.
  • The hard substratum provided by Lophelia, together with the strong currents in the areas it occupies, favours suspension feeding invertebrates, e.g. foraminiferans, sponges, hydroids, gorgonians (soft corals), corals, polychaetes, bryozoans, brachiopods, asteroids, ophiuroids, holothurians, and ascidians. For example, brittlestars, especially Ophiactis balli, were observed sheltering within the empty cups (calices) of dead corals with only their arms protruding (Rogers, 1999).
  • Mortensen (2001) suggested that there was a non-obligate mutualistic relationship between Lophelia and the polychaete Eunice norvegica, which shares a common distribution. In aquarium studies, Eunice norvegica was observed to steal food from the polyps of Lophelia, although Mortensen (2001) suggested that in nature Lophelia probably ingested live food before it could be stolen. Eunice norvegica was also observed to keep the coral surface clean of detritus and sedimentary particles, and in one instance attacked a sea urchin (Cidaris cidaris) that had climbed onto the coral. The polychaete may protect the coral from predators to some extent, a relationship seen in tropical coral communities (Mortensen, 2001). Most importantly, Eunice norvegica attaches its mucilaginous tube to the surface of the coral, which stimulates the coral to grow around and calcify the polychaetes' tube. This calcification may join adjoining coral branches, provide additional hard substrata for settlement of coral larvae and other invertebrates, and may strengthen the structure of the reef (Mortensen, 2001). In addition, tubes of the Eunice norvegica are capable of joining separate colonies, enhancing reef development, as seen in tropical corals (Dr Murray Roberts pers comm.).
  • The tubes of Eunice norvegica may also support other species of polychaete, e.g. the scale worm Harmothoe oculinarum.
  • Similarly, most bivalves were cavity dwellers occupying the empty calices of dead corals, e.g. Hiatella arctica and Acar nodulosa, while Delectopecten vitreus was found on the surface of live coral (Jensen & Frederiksen, 1992) and the giant file shell Acesta excavata may also use the coral as a substratum (Dr Jason Hall-Spencer pers comm.).
  • Jensen & Frederiksen (1992) observed only a few gastropods, the most numerous of which was Alvania jeffreysi, a predator of foraminifera. However, several species of gastropod have been recorded from Lophelia reefs (see Rogers, 1999), many of which are probably epifaunal grazers.
  • Many of the starfish and sea urchins recorded are probably epifaunal grazers and /or scavengers within the reef, while the mobile crustaceans including isopods, shrimp, crabs and hermit crabs are probably scavengers, or generalist predators of small invertebrates.
  • The coral skeleton may be eroded by several groups of organisms, e.g. bacteria, fungi, and sponges (e.g. Aka labyrinthica, Alectona millari and Cliona vastifera) which bore into dead corals, while eunicid, cirratulid, sabellid and spionid polychaetes also bore into the coral skeleton. Rogers (1999) noted that bioeroders play an important role in the development and maturation of coral reefs. Bioeroders reduce the coral skeleton to sediment, and weakens the coral structure so that pieces of coral break off or fall over. However, cavities produced by bioeroders also provide additional habitat complexity. Rogers (1999) noted that bioerosion in shallow coral reefs leads to rates of reef destruction that are only slightly slower than the rates of reef growth, so that any factor that reduces the growth rate of the corals may result in loss of the reef, especially since only a single cold-water coral species dominates this biotope.
  • Jensen & Frederiksen (1992) noted that many of the species they observed were only present as juveniles, suggesting that many species may use the Lophelia reef as a nursery area (Rogers, 1999).

Seasonal and longer term change

Lophelia reefs occupy relatively stable bodies of water (Rogers, 1999) but are still likely to experience seasonal fluctuations in current strength, temperature and food supply. The breaking of internal waves increases vertical mixing of the water column in areas of 'critical slope' (Frederiksen et al., 1997), which may occur close to the shelf break around the Faeroes Islands and the Faeroe-Shetland Channel interface (Roberts et al., 2003). Roberts & Anderson (2002a) noted that the polyps of Lophelia behaved asynchronously, without any clear diurnal patterns over a three day period in aquaria. Mortensen & Rapp (1998) detected distinct annual growth lines in Lophelia, and the growth of Lophelia from western Norway was carefully followed in aquaria over a 2.5 year period (Mortensen, 2001). Mortensen (2001) reported that linear extension of the skeleton was episodic, peaked in autumn, winter and spring, with a low growth period between June and September. In the aquaria, new polyps were generated mainly between August and December, the warmest part of the year, which suggested that temperature may be an important factor (Mortensen, 2001). However, deep-water population are probably not exposed to such temperature change. Mortensen (2001) observed no correlation between linear extension rates and temperature and salinity but concluded that the growth of the skeleton was correlated with seasonal variations in the abundance of particulate organic material and hence food availability.

The Lophelia reefs so far examined have been estimated to be extremely old, from several hundred to many thousands of years old. Therefore, although the longevity of individual coral polyps and associated species probably vary over time, the reef itself may be extremely long-lived (see 'time to reach maturity' below).

The associated fauna will probably exhibit seasonal fluctuations in abundance. For example, many bryozoan and hydroid species die back in the winter months. However, no other information was found.

Habitat structure and complexity

The shape and size of individual patches and reefs of Lophelia are highly variable, depending on local environmental conditions (Rogers, 1999). The density of branching varies and Lophelia may form robust 'bushes' in which the skeleton is thickened or finer more delicate branched colonies susceptible to damage e.g. from the pressure wave created by a submersible (Rogers, 1999). Reefs may be circular or 'halo-shaped', 'haystack-shaped', form domed mounds, or be elongated with one or more peaks, and the patches of reef may be arranged along the ridge of seamounts or banks in chains or 'islands groups' (Wilson, 1979a, b; Rogers, 1999; De Forges et al., 2000; Mortensen et al., 2001).

Wilson (1979b) suggested a model of Lophelia patch development, based on terms developed by Squires (1964), in which growth of an initial colony gives rise to coral fragments around it that either continue to grow or are colonized by Lophelia larvae. As the new colonies grow and merge they surround the central colony forming a 'thicket'. The central colony dies back, probably due to reduced water flow within the patch, and is reduced to coral debris, forming a halo shaped ring or 'coppice'. Subsequent phases of growth around the outside of the coppice results in concentric circles of growth forming a mature 'coppice' (see Wilson, 1979b for details). The reef becomes composed of several distinct zones, as exemplified by a Lophelia reef in the Stjernsund Fjord, Norway (Freiwald et al., 1997; Rogers, 1999). The living coral at the top of the reef grows on top of large fragments of dead coral, underneath which was a layer of small fragments and sediment. The living coral on top of the reef formed ring-shaped colonies as described by Wilson (1979b). Coral fragments from the main reef had also fallen down only to grow as spherical colonies. Away from the main reef Lophelia formed isolated coral thickets and dead collapsed frameworks (Rogers, 1999).

In the Darwin Mounds of the Rockall Trough, Masson et al. (2003) suggested that the mounds had preceded reef formation. In their study, Masson et al. (2003) observed no stratification of coral fragments in cores of the mounds, the cores being composed of quartz sand rather than bioclastic sediment. They concluded that mounds were formed by the deposition of sediment on the surface of the seabed by fluid escapes from the seafloor, and subsequently colonized by Lophelia and its associated fauna. The mounds form a raised substratum, which is a preferred habitat for Lopheliaand other suspension feeders (Masson et al., 2003).

The network of living and dead coral branches provide niches for a variety of organisms, e.g. bivalves and brittlestars within dead coral cups, and eunicids within and between the branches of corals (see above). However, the majority of the fauna observed were within and on the dead coral and coral debris (Rogers, 1999). Some coral mounds form acoustically detectable 'tails' aligned with the prevailing current, e.g. in the Darwin Mounds 'tails' included high densities of the giant protozoan Syringammina fragilissima (Masson et al., 2003).

Productivity

Frederiksen et al. (1997) suggested that Lophelia reefs on the continental slopes off Norway, west Scotland and the Faroes, occupy a depth at which tidal currents impinge on raised seabed features with a critical degree of slope to generate internal waves. The resultant mixing of the water column above the shelf break generates nutrient rich surface waters, that in turn promotes phytoplankton productivity. Similarly, the increased mixing of bottom waters leads to resuspension of organic particulates from the seabed. Both effects can potentially increase the supply of food to Lophelia and other suspension feeders (Rogers, 1999). Rogers (1999) also noted that the massive reef complex on the Sula Ridge, off Norway was thought to rely on the supply of zooplankton from fertile surface waters. The occurrence of some Lophelia reefs in the vicinity of light hydrocarbon or methane seeps has led to the hypothesis that Lophelia reefs and their associated fauna may be supported by a chemosynthetic food chain (Hovland & Thomsen, 1997; Hovland, et al., 1998). But Rogers (1999) concluded that the evidence was equivocal. For example, occurrences of Lophelia in the Rockall Bank and elsewhere are not associated with hydrocarbon seeps (Rogers, 1999). Analysis of stable radiocarbon isotope (13C) levels in the skeleton of Lophelia pertusa and 13C/12C ratios in tissue is not consistent with a food chain based on hydrocarbon seeps (see Rogers, 1999 and Roberts et al., 2003 for discussion). Rogers (1999) suggested that most of the hydrocarbons are utilized by other organisms at the sediment-water interface.

Although, the only living part of the Lophelia framework are the surface colonies, the skeletal framework provides substratum, interstices, refugia and feeding grounds for a wide variety of other organisms. Most of the biomass of the reef is provided by the associated fauna, especially in smaller reefs (Rogers pers comm.). Overall, Lophelia reefs are probably highly productive ecosystems (secondary productivity) but no direct information was found. Lophelia reefs probably exhibit tight coupling between the pelagic and benthic ecosystems (Dr Murray Roberts, pers comm.).

Recruitment processes

Colonies of Lophelia grow by intratentacular budding, the division of an existing polyp into two polyps (Cairns, 1979; Rogers, 1999). In addition, Lophelia may generate new colonies by fragmentation, whereby coral fragments fall or are broken off, and continue to grow under suitable conditions. Fragmentation is a major mechanism whereby the initial colony expands to form a coppice and ultimately a reef (see 'habitat complexity' above and Wilson, 1979b). Some corals can reproduce by parthenogenesis, the development of an un-fertilized egg, while others exhibit 'polyp bailout' in which a polyp or piece of coral tissue leaves its skeleton, and moves to a suitable substratum and secretes a new skeleton (Richmond, 1997). However, there is currently no evidence for the existence of parthenogenesis or 'polyp bailout' in Lophelia (Rogers, 1999).

The mechanism of sexual reproduction in Lophelia pertusa is unknown (Rogers, 1999). About 25% of coral species have separate sexes while the majority are hermaphrodite, i.e. possess both male and female reproductive organs. In some species fertilization occurs externally and eggs and sperm are spawned into the sea. In other species fertilization occurs internally and the larvae develop and are brooded within the parent colony (Richmond, 1997). The larva of corals is the ciliated planula larvae. In species studied, the externally fertilized planula has been calculated to remain competent and capable of recruitment for 3-4 weeks. Brooded planula larvae tend to have a longer competence period, e.g. estimated to be over 100 days in Pocillopora damicornis (Richmond, 1997). The prolonged competency period is attributed to the provision of symbiotic zooxanthellae in brooded planulae that supplement larval energy reserves (Richmond, 1997). Cold-water corals, such as Lophelia, lack zooxanthellae, however Roberts (2002a) noted that larval competency in cold temperate waters may be considerably longer than observed in tropical waters.

The planula larvae of Lophelia pertusa require hard substrata for settlement, including rock surfaces, artificial substrata, coral fragments or hydrocarbon seep associated carbonates. In sedimentary areas, Lophelia pertusa may settle on hard substrata as small as a shell, pebble, or worm tube (Rogers, 1999). However, a hard substratum is a pre-requisite for settlement and a layer of sediment may interfere with settlement and hence recruitment.

Whilst Rogers (1999) noted that there was no indication of the dispersive capability of Lophelia pertusa, its ability to colonize isolated hard substrata and artificial substrata such as submarine cables, the Brent Spar storage buoy and oil rigs suggests that it has a pelagic larval phase (Rogers, 1999; Roberts, 2002a). Roberts (2002a) concluded that the occurrence of Lophelia on structures in the Beryl and Brent oil fields in the North Sea was good evidence for a dispersive planula larva. Roberts (2002a) suggested that the colonies in the North Sea oil fields originated as larvae from the offshore banks of the Atlantic margin, and were carried into the North Sea in cooled Atlantic water, possibly via the east Shetland Atlantic Inflow current. Transport of larvae in the water mass of prevailing water currents probably provides the opportunity for long distance dispersal.

The recent evidence (above) suggests that larvae are dispersive but that migration is not sufficient to counteract reproductive isolation of populations (Dr Alex Rogers pers comm.). Molecular genetic data is somewhat confused at present but microsatellite data indicates that Beryl oil fields samples of Lophelia are closely related to northern Rockall Trough populations and that there is strong genetic differentiation (population sub-division), with very low gene flow between areas (Dr Alex Rogers pers comm.). Present evidence suggests that asexual reproduction predominates in reef growth and that the contribution from larvae may be limited. Therefore, molecular genetic data suggests that recolonization of a disturbed areas is likely to be slow (Le Goff-Vitry & Rogers, 2002, summary only, Dr Alex Rogers pers comm.).

The associated epifauna and interstitial fauna probably depend on locality and recruit from the surrounding area. Many hydroids, ascidians and probably sponges have short lived planktonic or demersal larvae with relatively poor dispersal capabilities. Exceptions include Alcyonium digitatum and hydroids that produce medusoid life stages and probably exhibit relatively good dispersal potential. Hydroids are opportunistic, fast growing species, with relatively widespread distributions, which colonize rapidly and are often the first groups on species to occur on settlement panels. Sponges may take longer to recruit to the habitat but are good competitors for space. Recruitment in epifaunal communities is discussed in detail in the faunal turf biotopes MCR.Flu, CR.Bug and in Modiolus modiolus beds (MCR.ModT). Mobile epifaunal species, such as echinoderms (starfish and brittlestars), crustaceans, and fish are fairly vagile and capable of colonizing the community by migration from the surrounding areas. In addition, most echinoderms and crustaceans have long-lived planktonic larvae with potentially high dispersal potential, although, recruitment may be sporadic, especially in echinoderms.

Time for community to reach maturity

Mortensen et al. (2001) suggested that the size of Lophelia reefs was determined by the time taken for development and the topography of the seabed that affects both the area over which coral fragments and rubble can spread and the local currents and hence, food supply and growth rates.

The growth rate of Lophelia is very slow. Estimates of growth rate range from 2 to 25 mm/yr. depending on location (Wilson, 1979b; Rogers, 1999; Hall-Spencer et al., 2002; Roberts, 2002a) although inaccurate sampling of the coral skeleton may have led to biased estimates. Studies of growth lines suggested a mean extension rate of 5.5 mm/yr., with linear extension rates greatest in the early stages of polyp growth, slowing with age (Mortensen & Rapp, 1998). Measurement of linear extension rates in aquarium specimens gave a mean annual growth rate of 9.4 mm/yr. (Mortensen, 2001). Rates of growth on artificial structures were estimated to range from 6 mm/yr. on submarine cables in north west Spain to 26 mm/yr. on the Brent Spar storage buoy (Bell & Smith, 1999; Roberts, 2002a).

Estimates of potential age of Lophelia colonies and reefs vary with location and with the growth rates estimates used to calculate age. For example, Wilson (1979b) estimated that a single colony 1.5 m in height would probably be 200 -366 years old (based on a growth rates between 7.5 and 4.1 mm/yr. respectively). Lophelia reefs sampled off Norway, 25 m in height and 330 x 120 m in area were probably between 1,000 and 6,250 years old, depending on growth rate (Rogers, 1999). Radiocarbon dating of cold-water corals from west Ireland, provided estimated ages of 451 years before present (BP) for live Lophelia pertusa and 762 years BP for dead Lophelia pertusa fragments (Hall-Spencer et al., 2002). However, dead coral rubble formed by the cold-water coral Desmophyllum cristagalli, at the same site, were between 4067 and 5001 years BP, which suggested that the reef system was probably at least 4,500 years old (Hall-Spencer et al., 2002). The age of Lophelia reefs in south east Norway and west of Fedje Island, west Norway was estimated to be 8,700 and 3,600 years BP respectively (Mikkelsen et al., 1982; Rokoengen & Østma, 1985; Mortensen et al., 2001). The Lophelia reefs of the Sula Ridge were estimated to be 8,600 years old, having developed over the last 10,000 years since the last ice age (Hovland & Mortensen, 1999; Mortensen et al., 2001). Coral rubble from cold-water coral reefs on the Florida Hatteras slope, which was not ice covered, had an age of ca 20,230±230 years BP (Mortensen et al., 2001).

Recruitment to available hard substrata by epifauna such as hydroids, and ascidians is probably fairly rapid (see MCR.Flu or CR.Bug), with sponges and soft corals taking longer to develop. Bryozoans, hydroids, and ascidians are opportunistic, grow and colonize space rapidly and will probably develop a epifaunal cover within 1-2 years (for example see Sebens, 1985, 1986). Mobile epifauna and infauna will probably colonize rapidly from the surrounding area. Slow growing species such as some sponges and anemones (see Sebens, 1985, 1986), will probably take many years to develop significant cover, so that a diverse community may take up to 5 -10 years to develop, depending on local conditions.

While, epifaunal and infaunal species would colonize relatively rapidly, the key species determining the development of the reef is Lophelia itself. Deep-sea communities are thought to have very slow colonization rates (Rogers, 1999). While Lophelia may have a dispersive larval stage (see Roberts, 2002a), there is little information available on recruitment rates in natural systems. However, recent molecular genetic data suggests that larval recruitment is probably low or sporadic (Le Goff-Vitry & Rogers, 2002, summary only; Dr Alex Rogers, pers comm.). Overall, even with good recruitment, Lophelia is very slow growing and would probably take several hundred years to develop large colonies (ca 1.5-2 m in diameter) and several thousand years to develop a reef system 10 -30 m thick (Fosså et al., 2002).

Additional information

None entered.

Preferences & Distribution

Recorded distribution in Britain and Ireland

Reefs of Lophelia pertusa have been recorded on raised offshore seabed features from the Shetland-Faroe Basin, Rockall Bank and Rockall Trough, Anton Dohrn Seamount, Rosemary Bank, Hatton Bank, Bill Bailey's Bank, and the Wyville-Thomson Ridge in the north Atlantic off Britain, and in the Porcupine Seabight and Porcupine Basin off west Ireland. The map shows the recorded distribution of Lophelia pertusa, including isolated colonies as well as reefs.

Habitat preferences

Depth Range 50-100 m
Water clarity preferences
Limiting Nutrients
Salinity Full (30-40 psu)
Physiographic Open coast
Biological Zone Circalittoral, Lower circalittoral
Substratum Artificial (man-made), Bedrock, Features / other, Fine clean sand, Hard (immobile), Hard (mobile), Pebbles
Tidal Moderately Strong 1 to 3 knots (0.5-1.5 m/sec.), Weak < 1 knot (<0.5 m/sec.)
Wave Extremely sheltered
Other preferences Oceanic water

Additional Information

Distribution
Lophelia pertusa has been recorded globally from the North Atlantic, parts of the Mediterranean, along the coasts of west Africa, the United States, east Canada and around the mid Atlantic islands south to Tristan da Cunha. It is also recorded from the Pacific, southern California, Cobb Seamount, and from the Island of St Paul in the Indian Ocean. There is also a single record from the Macquarie Ridge, south of New Zealand (Rogers, 1999). However, records often refer to dead or subfossil remains, may not represent reefs in all cases, and Lophelia often occurs as isolated patches over large areas of seabed, making it difficult to detect. Therefore, its living distribution may be inaccurate (Rogers, 1999). Recent genetic evidence suggests that Brazilian records of Lophelia are genetically distinct and may represent a different species or sub-species (Le Goff-Vitry et al., in press; Dr Alex Rogers, pers comm.).

Lophelia pertusa has been recorded from the continental shelf of the north east Atlantic more frequently than any other place in the world (Rogers, 1999). In addition, to records in British and Irish waters, Lophelia reefs have also been recorded from Norwegian fjords, and on raised offshore seabed features from Haltenbanke, Froyabanken and the Sula Ridge in south and west Norway, the Faroes shelf, and from the Porcupine Basin south along the continental shelf edge to North Africa (Rogers, 1999; ICES, 2002; Roberts, 2002b; A. Grehan pers. comm.). Scattered records also occur in the North Sea, the Outer Hebrides, Stanton Bank, and Donegal Basin (Rogers, 1999; Roberts et al., 2003). A review of the distribution of cold water coral in European waters is provided by Zibrowius (1980) and a detailed list of records is presented by Rogers (1999).

Habitat preferences

  • Lophelia pertusa requires hard substrata (e.g. rock, coral fragments, artificial substrata, or hydrocarbon seep associated carbonates) on which to settle. Colonies that occur in sedimentary habitats have settled on small pieces of hard substrata such as pebbles, shells or worm tubes (Rogers, 1999).
  • Lophelia pertusa appears to prefer the presence of oceanic waters. For example, Lophelia only occurs in Norwegian fjords that allow deep oceanic water into the fjord; its upper limit determined by the depth of coastal waters (Rogers, 1999).
  • Its preference for oceanic waters suggested that Lophelia was sensitive to salinity and temperature (Rogers, 1999). Lophelia pertusa is found in water between 4 and 12 °C (Rogers, 1999) but records from the Mediterranean suggest it can survive up to 13 °C (Mortensen, 2001). Rogers (1999) noted that Lophelia is not usually found in waters colder than 6 °C but that it may encounter lower temperatures at the lower limits of its depth range. In a recent study, Roberts et al. (2003) noted a strong correlation between the occurrence of Lophelia and temperature. With a single exception, Lophelia had not been recorded in waters colder than 4 °C and was absent from depths of greater than 500 m in the Faeroe-Shetland Channel, presumably due to the influence of cold Nordic waters (e.g. the Arctic Intermediate Water and/or Norwegian Sea Arctic Water with temperatures of 1 -5 °C or -0.5 to 0.5 °C respectively) (Roberts et al., 2003). The only record of Lophelia in the Faeroe-Shetland Channel below 500 m occurred in an area subject to temperatures below 4 °C for 52% of a 10 month period of observations and below zero for 4% of the same period (Bett, 2000). Roberts et al. (2003) suggested that the above record probably represented the limit of Lophelia pertusa's range but that present evidence suggested that seabed mounds associated with coral growth were unlikely at depths influenced by cold Nordic waters.
  • Lophelia pertusa occurs in waters of 35 -37 psu but in fjords tolerates salinities as low as 32 psu (Rogers, 1999; Mortensen et al., 2001).
  • The upper limit of Lophelia in fjords corresponds to the position of the thermocline (Rogers, 1999). However, Frederiksen et al. (1992) considered the origin of the water masses to be more important, while Mortensen et al. (2001) suggested that the pycnocline between lower salinity, warmer coastal waters and deeper, cooler oceanic water resulted in more stable conditions within the fjords, and a strong influx of oceanic waters.
  • The upper limit of Lophelia in oceanic waters is probably seen on oil platforms in the North Sea. Lophelia pertusa was reported growing on single point moorings of the Beryl Alpha platform between depths of 75 and114 m (Roberts, 2002a). The water column around the platform was stratified; the salinity varied from 34.8 ppt at the surface to just over 35 ppt at 50 m, while the surface temperature remained fairly constant at 11.5 °C to a depth of 50 m before dropping rapidly to 8 °C between 70 and 110 m (Roberts, 2002a). Roberts (2002a) noted that the depth of Lophelia corresponded with 8 °C and a salinity of 35 ppt. He suggested that Lophelia was restricted to depths of greater than 70 m by the physical conditions, competition from other epifauna (e.g. sponges and sea anemones) and possibly by wave action during storms (Roberts, 2002a).
  • Strong current flow appears to be required for growth in Lophelia, which occurs in areas of strong water flow. Lophelia reefs occur where the topography causes current acceleration, e.g. on raised seabed features such as seamounts and banks and where the channel narrows in Norwegian fjords (Rogers, 1999). For example, soft corals were reported to reach higher densities near the peaks of seamounts rather than the slopes, or along the edges of wide peaks (see Rogers, 1999). Frederiksen et al. (1992) suggested that topographical highs create internal waves, depending on slope, that resuspended organic particulates from the seabed, and increase the flux of nutrient-rich waters to the surface waters increasing phytoplankton productivity; both effects resulting in increased food availability for Lophelia and other suspension feeders.
  • Water flow is important for suspension feeders and passive carnivores, such as Lophelia, to provide adequate food, oxygen and nutrients, to remove waste products and prevent sedimentation, however, the optimum current speed varies with species (see Hiscock, 1983 for discussion). For example, Mortensen (2001) observed no polyp mortality in the vicinity of his aquaria inlets but high mortality at the opposite end. Similarly, the death of coral polyps within a coral coppice is thought to be due to reduced water flow within the colony (Wilson 1979b). Mortensen (2001) also noted that high current flow (greater than ca 0.05 m/s) was detrimental to growth, presumably due to reduced food capture rates. Frederiksen et al. (1992) suggested that Lophelia reefs around the Lousy and Hatton Banks would typically encounter currents speeds of 0.01 -0.1 m/s. Water flow rates >0.4 m/s were recorded by moored and landed deployed current meters close to deep-water coral mounds in the Porcupine Seabight (White , 2001 cited in Grehan et al., 2003), while Masson et al. (2003) recorded a maximum residual bottom water flow of 0.35 m/s over a 20 day period in July 2000 over the Darwin Mounds. Food availability may be of greater importance than current speed alone.
  • Around the Norwegian /Scottish Shelf and Faroes, Lophelia most commonly occurs at depths between 200 -400 m, and between 200 -1000 m in the Massifs off west Ireland and the Bay of Biscay, and in some records extends to 3000 m (Rogers, 1999). Rogers (1999) suggested that its deepest limit may coincide with the oxygen minimum zone.
  • In deep waters the upper limit of Lophelia is probably controlled by the transition from oceanic to coastal or surface waters (see Rogers, 1999). However, Lophelia reefs occur as shallow as 50 m in Norwegian fjords. Frederiksen et al. (1992) suggest that its upper limit is controlled by wave action. Draper (1967) noted that wave periods in offshore areas are generally of longer than in enclosed seas and therefore penetrate to greater depths. However, Draper (1967) estimated that as far out as the continental shelf, for one day a year, storm conditions could generate a oscillatory water movement on the seabed of only ca 0.4 m/s at 180 m. Wave mediated currents are oscillatory and possibly more likely to result in damage to rigid corals than water flow (see Hiscock, 1983), although their skeletons are quite robust (Dr Jason Hall-Spencer pers comm.). In Norwegian fjords where Lophelia reefs occur as shallow as 50 m, wave action is slight at the surface and most likely does not penetrate more than a few tens of metres. Inner fjords have limited fetch so that wave action is unlikely to penetrate to more than a few tens of metres even in storm conditions (Dr Keith Hiscock pers. comm.). Rogers (1999) noted that the upper limit of Lophelia in the Norwegian fjords also coincided with the thermocline, and that the turbidity of the coastal surface water also reduced competition from algae.
  • It has been suggested that Lophelia reefs are associated with hydrocarbon or methane seeps (Hovland & Thomsen, 1997; Hovland, et al., 1998). But Rogers (1999) concluded that the evidence was equivocal. For example, occurrences of Lophelia in the Rockall Bank and elsewhere are not associated with hydrocarbon seeps (Rogers, 1999). Analysis of stable radiocarbon isotope (13C) levels in the skeleton of Lophelia pertusa and 13C/12C ratios in tissue is not consistent with a food chain based on hydrocarbon seeps (see Rogers, 1999 and Roberts et al., 2003 for discussion). Rogers (1999) suggested that most of the hydrocarbons are utilized by other organisms at the sediment-water interface. However, in some locations the hydrocarbon seep associated carbonates may provide hard substrata for settlement in an otherwise sedimentary habitat.

Overall, Lophelia reefs require hard substrata, the presence strong currents and a good food supply, usually associated with raised seabed features, banks and sea mounts. Lophelia occupies a relatively narrow range of temperatures (stenothermal) and salinity (stenohaline), although its upper limit may be determined by a number of factors.

Species composition

Species found especially in this biotope

Rare or scarce species associated with this biotope

-

Additional information

Rogers (1999) collated species lists from all previous studies of Lophelia reefs in the north-east Atlantic and noted that about 886 species had been recorded, although this number of species is probably an under-estimate. Diverse species groups include the Foraminifera, Polychaeta, Echinodermata, and Bryozoa. The diversity of polychaetes, echinoderms and bryozoans recorded from Lophelia reefs is similar to that found on shallow water tropical coral reefs (Rogers, 1999). However, Scleractina (corals), Mollusca and Pisces (fish) have relatively low diversities compared to tropical reefs (see Rogers, 1999). Jensen & Frederiksen (1992) suggested that most species present were not strongly associated or endemic to the Lophelia reefs they studied, however the associated community is still poorly understood (Rogers, 1999). Recent studies of the fauna of coral-water coral reefs on seamounts off Tasmania by Koslow et al. (2001) recorded 262 species of invertebrates of which 24 -43% were new to science and 16 -33% were restricted to the seamount environment, while De Forges et al. (2000) recorded 850 species of mega and macrofauna of which 29 -34% were new to science and were potential seamount endemics. Overall, cold water coral reefs represent biodiversity hot spots within their area. For example, Masson et al. (2003) reported that initial studies suggested that invertebrate density was about 2-3 times higher on the Darwin Mounds than the surrounding sediments. Further study is required to estimate the biodiversity of northeast Atlantic Lophelia reefs and seamounts.

Sensitivity reviewHow is sensitivity assessed?

Sensitivity characteristics of the habitat and relevant characteristic species

Lophelia pertusa is the only characterizing species within SS.SBR.Crl.Lop this reef forming scleractinian coral is the most common reef framework forming, cold-water coral.  Lophelia pertusa colonies can grow to several metres, and branches of separate colonies can anatomise, strengthening the structure of the reef (Roberts et al., 2009).  The complex reef formations which are created by Lophelia pertusa provide a range of niches which host wide number of species (Buhl & Mortensen et al., 2005; Mortensen et al., 2010; Freiwald et al., 2004; Muller et al., 2013).  A total of 1317 species have been listed associated with Lophelia pertusa reefs within the North East Atlantic (Roberts et al., 2006).  Therefore, although there is not a full species list associated with this biotope, it is likely that it will have high species diversity.  Henry & Roberts (2007) found that the biodiversity within cold-water coral reefs containing Lophelia pertusa in the North East Atlantic was typically greater than that in neighbouring habitats.  Jonsson et al. (2004) also found that there was a decrease in the biodiversity and the abundance of individuals the further from a Lophelia pertusa reef within a Swedish fjord.  The increase in biodiversity around Lophelia pertusa reefs shows that they are important ecosystem engineers.  Therefore, while Lophelia pertusa is not the only coral species found in the cold-water corals reefs of the North East Atlantic, it is the major reef forming species and, hence the focus for sensitivity assessment.  

Resilience and recovery rates of habitat

Lophelia pertusa has a worldwide distribution.  However, records show it to be most abundant in deep waters, at high latitudes in the North East Atlantic (Davies et al., 2008).  Global oceanographic data show that Lophelia pertusa is found at a mean depth of 480 m, and where current speeds and productivity are higher than average (Davies et al., 2008).  Until the 1990’s little scientific information was available on Lophelia pertusa.  However, the rapid growth in commercial deep-water activities such as bottom trawling and offshore hydrocarbon exploration, meant that greater understanding of deep-water ecosystems was needed.  Although there is extensive literature on the destruction of cold-water coral reefs through anthropogenic pressures, there is almost no information regarding the recovery of these habitats.

The oldest radiocarbon dated Lophelia pertusa colony was found off the coast of Norway and was between 7800 – 8800 years old (Mikkelson et al., 1982; Hovland et al., 1998; Hovland & Mortensen, 1999).  Lophelia pertusa caught as by-catch from the west coast of Ireland was found to be at least 4550 years old (Hall-Spencer et al., 2002).  In the high latitudes in the North East Atlantic, the growth of Lophelia pertusa reefs is unlikely before 10,000 years ago, due to the extent of ice during the last ice age (Schröder-Ritzrau, 2005).  The growth of Lophelia pertusa varies.  The lowest recorded growth rate was 5mm / annum (Roberts, 2002a) with the highest being 34 mm/ annum (Gass & Roberts, 2006).

Lophelia pertusa is gonochoristic and is thought to spawn annually (Waller, 2005).  Evidence from the North East Atlantic Lophelia pertusa supports this supposition, and samples collected within this area showed a seasonal reproductive cycle with a single cohort per year, with a spawning event around February (Waller & Tyler 2005).  Asexual replication of Lophelia pertusa polyps occurs by unequal intratentacular budding (Cairns 1979, 1994; Roberts et al., 2009; Brooke & Jarnegren, 2013).  Fragmentation of the coral skeleton is part of the process of reef growth and development (Wilson, 1979b; Rogers, 1999).  Therefore, minor damage to colonies is probably a natural process within reef formation.  Lophelia pertusa larvae have to settle onto hard substrata, yet the reefs can spread out over soft sediment.  The reef structure its self can also engineer the physical environment around it (Roberts et al., 2009).  The reef structure created by Lophelia pertusa modifies the water flow regime within the reef (Mullins et al., 1981).  The complex structure of the reef slows down water flow and this can cause sediments to fall out of suspension.  The reef also provides a wide range of niches for other species, the increase in biological activity within the reef can also increase sedimentation (Roberts et al., 2009).

Maier (2008) found that, in aquaria, severely fragmented pieces of Lophelia pertusa collected during survey work showed considerable recovery potential.  Damaged Lophelia pertusa were maintained in aquaria for a number of months, during which time they were fed regularly.  During the time of experiment corallite pieces as small as 3 mm showed regeneration (Maier, 2008).  Maier (2008) noted that although this regeneration was possible within aquaria, corals are not guaranteed to survive damage in the field due to destruction of the coral framework, sedimentation and other factors not present within the aquaria experiment.  However, it does show that cold-water coral propagation within aquaria is possible.  

Gass & Roberts (2006) found Lophelia pertusa examined 14 oil and gas platforms within the North Sea and found Lophelia pertusa to be growing on 13 of them.  Two of the platforms were examined more closely and 947 individual colonies were found, the largest of which was 132 cm in diameter (Gass & Roberts, 2006).  The North Alywn Alpha and Healther Alpha platforms provide a 20 – 30 year settlement experiment within the North Sea Gass & Roberts (2006).  Prior to the oil and gas platforms within the North Sea there were no known records of live Lophelia pertusa.  Larvae recruited to these North Sea platforms have probably been transported in the North Atlantic water mass entering the North Sea.  The nearest known Lophelia pertusa colonies to the North Sea are from the west coast of Scotland.  Lophelia pertusa larvae are most likely to have reached the North Sea via the substantial inflow of Atlantic water flowing southwards east of Shetland from the Atlantic shelf edge current and the Fair Isle Current (Roberts, 2002; taken from Gass & Roberts, 2006).

Evidence of reef recovery within the field is severely lacking.  Roberts et al. (2006) stated that cold-water coral reefs have been severely damaged by trawling for deep-water fish, causing severe physical damage from which recovery to former reef status will take several hundreds or thousands of years, if at all (Freiwald et al., 2004; Fosså et al., 2002; Hall-Spencer, 2002).  Growth rates are slow, the age of the reefs which have been carbon dated show that they have been undisturbed for long periods of time.  For a single Lophelia pertusa colony to grow to 1.5 m high could take 200 -366 years depending on growth rate (Rogers, 1999).  Colonies of Lophelia pertusa growing in close proximity merge to create a reef structure.  These reef formations grow up into the water column, which elevate the organisms and allow them to protrude further out into the fast moving water flows.  Old reefs can create mounds tens of metres high, and hundreds of metres wide.  The period of time for which Lophelia pertusa reefs to return to full ecosystem function is unclear, but an estimate of hundreds of years is not unrealistic.  If a reef thousands of years old has been damaged then the time for the reef to return to its previous state would take an equal length of time if conditions for recruitment were still favourable.  The formation of cold-water coral reefs is complex and fully explained by Roberts et al. (2009).

Sensitivity assessment.  The ability of Lophelia pertusa to recover from natural or anthropogenic damage is poorly understood (Brooke & Jarnegren, 2013).  There is extensive evidence for the damage of Lophelia pertusa, yet there is no evidence for the natural recovery of any of these damaged reefs.  From experiments within controlled aquaria there is evidence that Lophelia pertusa can recover from very small fragments (Maier, 2008).  However, there is no evidence of this occurring in the field.  Oil and gas platforms provide evidence that the larvae of Lophelia pertusa have the potential to travel extensive distances and can grow to considerable sizes within 20 – 30 years.  Although this evidence suggests that Lophelia pertusa has the potential to recover relatively quickly within certain controlled aquaria conditions, it does not take into consideration the age of the Lophelia pertusa reefs which are the basis of this biotope.  The oldest Lophelia pertusa reefs in the North East Atlantic have been found to be between 7800 – 8800 (Mikkelson et al., 1982; Hovland et al., 1998; Hovland & Mortensen, 1999).  It is now widely accepted that anthropogenic pressures are having a negative effect on cold-water coral reefs, including those containing Lophelia pertusa (Roberts & Cairns 2014).  However, the lack of knowledge regarding the worldwide distribution of the cold-water reef habitats, makes it very difficult to determine how much habitat has been lost to anthropogenic pressures.  There are, however, a number of recorded cases of Lophelia pertusa reefs being lost from the north east Atlantic.  Fosså et al. (2002) documented and photographed the damage caused to west Norwegian Lophelia pertusa reefs by trawling activity (see Fosså, 2003 for photographs).  They reported that four, out of five sites studied, contained damaged corals. In the shallow regions of Sørmannsneset, only fragments of dead Lophelia pertusa were seen, spread around the site with no evidence of living colonies in the surrounding area, and Fosså et al. (2002) concluded that the colonies had been "wiped out".  Overall, they estimated that between 30 and 50% of Lophelia pertusa reefs are either impacted or destroyed by bottom trawling in western Norway.  From the west coast of Ireland widespread bottom trawling damage of Lophelia pertusa reefs has been found between 840 – 1300 m (Hall-Spencer et al., 2004).  Lophelia pertusa has also been identified within the by-catch of deep-water fishing vessels trawling off the west coast of Ireland (Hall-Spencer et al., 2002).  Other papers that provide evidence for the damage of cold-water coral reefs through bottom trawling include Hall-Spencer et al. (2002), Grehan et al. (2003), Wheeler et al. (2005), Roberts et al. (2006), Alhaus et al. (2009), Roberts &Cairns (2014).  In addition to deep-water fisheries, the hydrocarbon industry, mining, and ocean acidification have all been found to degrade the health of cold-water coral reefs (Roberts et al., 2009). 

Pressures will affect Lophelia pertusa in two ways.  Firstly, a pressure could cause mortality of the coral polyps.  This would leave the reef structure intact, however, the loss of the polyps will mean that the reef will no longer be maintained and it will stop growing.  If all of the polyps are killed then the reef structure will degrade and be lost over time.  Secondly, a mechanical pressure could destroy the reef structure.  This would lead to the immediate loss of the reef structure, which would remove the polyps from their optimum conditions.  The polyps may not die immediately, however, they are likely to die within weeks of the pressure event through stress and the effect of secondary pressure caused by the reef destruction.  Eventually both of these effects will cause the same effects and therefore, they are assessed to have the same resilience.  Where resistance is ‘None’, ‘Low’, ‘Medium’, resilience is assessed ‘Very low’.  There is no evidence from case studies that shows Lophelia pertusa reefs recovering from damage, so it is unclear if Lophelia pertusa will ever recover.

Hydrological Pressures

 ResistanceResilienceSensitivity
Low Very Low High
Q: High
A: High
C: Medium
Q: High
A: High
C: High
Q: High
A: High
C: Medium

Lophelia pertusa distribution is controlled by a number of environmental factors, including; temperature, oxygen saturation, food supply, and carbonate chemistry (Roberts et al., 2009; Georgian et al., 2014).  The distribution of Lophelia pertusa in the North Atlantic appears to correlate with water masses within certain temperature ranges rather than other environmental factors (Frederiksen et al., 1992; Freiwald,1998).  Lophelia pertusa is typically found in areas where temperatures range from 4 to 12 °C (Lunden et al., 2014).  Lophelia pertusa around the UK, Ireland, Norway are found in water temperatures 6 to 8◦C (Zibrowius, 1980; Frederiksen et al., 1992; Freiwald et al., 2004).  Within the Mediterranean, Tursi et al. (2004) recorded Lophelia pertusa living within areas with sea temperatures between 12.5 to 14 °C; the upper limit of the species tolerance.  Temperature fluctuations measured within Lophelia pertusa reefs range between 1 and 2 °C (Schroeder, 2002; Wisshak et al., 2005; Davies et al., 2009; cited by Form & Riebesell, 2012).  The small temperature fluctuations recorded within Lophelia pertusa and the extremely long lived nature of the reefs suggests that the species is not tolerant of large fluctuations in temperature for extended periods of time.  Dodds et al. (2007) found that when Lophelia pertusa collected from the Mingulay reef complex were exposed to temperatures greater than those experienced within the reef, metabolic rates of Lophelia pertusa increased dramatically.  For a 2 °C increase in temperature (from 9°C to 11°C) oxygen consumption doubled (Dodds et al., 2007).  This in turn increased the higher energetic demands and led to greater food requirements (Dodds et al., 2007).  Lunden et al. (2014) found that when Lophelia pertusa, collected within the Gulf of Mexico, were exposed to temperatures >14°C there was 100% mortality within their sample.  Rogers (1999) suggested that death of coral on the upper reaches of a reef may reflect changes in the depth of the thermocline.  But the upper limit of the Lophelia pertusa reefs may be attributed to other factors, e.g. the origin of the water masses, salinity, wave action, or competition with other species e.g. sponges (Frederiksen et al., 1992; Rogers, 1999; Mortensen et al., 2001; Dr Alex Rogers, pers comm.). 

A single Lophelia pertusa was reported on the Beryl Alpha platform between depths of 75 and114 m (Roberts, 2002a).  The water column around the platform was stratified; the salinity varied from 34.8 ppt at the surface to just over 35 ppt at 50 m, while the surface temperature remained fairly constant at 11.5°C to a depth of 50 m before dropping rapidly to 8°C between 70 and 110 m (Roberts, 2002a).  Roberts (2002a) noted that the depth of Lophelia pertusa corresponded with 8°C and a salinity of 35 ppt.  He suggested that Lophelia pertusa was restricted to depths of greater than 70 m by the temperature and salinity, competition from other epifauna (e.g. sponges and sea anemones) and possibly by wave action during storms (Roberts, 2002a).

Sensitivity assessment.  Lophelia pertusa is an extremely long lived species, and is found in deep water where it is isolated from rapid acute changes in temperature.  Short term temperature fluctuations found within Lophelia pertusa reefs have been recorded at 1 -2 °C.  An increase in temperature to the level of the benchmark is likely to stress the organisms.  Experiments have shown that an increase in temperature to increase metabolic rate, and consequently the organism’s food requirement.  There is no empirical evidence of the effect of temperature changes at the level of the benchmark.  However, our knowledge of the conditions within which Lophelia pertusa are found suggests that it would be removed from optimum conditions and thus may suffer negative impacts.  Death of the coral polyps themselves would not immediately result in loss of the reef and the associated species.  The associated species, especially epifauna would be lost over a period of years as the coral matrix was slowly eroded to coral rubble and eventually sediment.  Although Lophelia pertusa may be able to colonize the substratum in the meantime, it would still take many years to replace the original reef.  A resistance of ‘Low’ has been given with a r resilience of ‘Very Low’, which consequently gives a sensitivity of ‘High’.  

Low Very Low High
Q: High
A: High
C: Medium
Q: High
A: High
C: High
Q: High
A: High
C: Medium

Lophelia pertusa distribution is controlled by a number of environmental factors, including; temperature, oxygen saturation, food supply, and carbonate chemistry (Roberts et al., 2009; Georgian et al., 2014).  The distribution of Lophelia pertusa in the North Atlantic appears to correlate with water masses within certain temperature ranges rather than other environmental factors (Frederiksen et al., 1992; Freiwald,1998).  Lophelia pertusa is typically found in areas where temperatures range from 4 to 12 °C (Lunden et al., 2014).  Lophelia pertusa around the UK, Ireland, Norway are found in water temperatures 6 to 8◦C (Zibrowius, 1980; Frederiksen et al., 1992; Freiwald et al., 2004).  Within the Mediterranean, Tursi et al. (2004) recorded Lophelia pertusa living within areas with sea temperatures between 12.5 to 14 °C; the upper limit of the species tolerance.  Temperature fluctuations measured within Lophelia pertusa reefs range between 1 and 2 °C (Schroeder, 2002; Wisshak et al., 2005; Davies et al., 2009; cited by Form & Riebesell, 2012).  The small temperature fluctuations recorded within Lophelia pertusa and the extremely long lived nature of the reefs suggests that the species is not tolerant of large fluctuations in temperature for extended periods of time.  Rogers (1999) suggested that death of coral on the upper reaches of a reef may reflect changes in the depth of the thermocline.  But the upper limit of the Lophelia pertusa reefs may be attributed to other factors, e.g. the origin of the water masses, salinity, wave action, or competition with other species e.g. sponges (Frederiksen et al., 1992; Rogers, 1999; Mortensen et al., 2001; Dr Alex Rogers, pers comm.). 

A single Lophelia pertusa was reported on the Beryl Alpha platform between depths of 75 and114 m (Roberts, 2002a).  The water column around the platform was stratified; the salinity varied from 34.8 ppt at the surface to just over 35 ppt at 50 m, while the surface temperature remained fairly constant at 11.5°C to a depth of 50 m before dropping rapidly to 8°C between 70 and 110 m (Roberts, 2002a).  Roberts (2002a) noted that the depth of Lophelia pertusa corresponded with 8°C and a salinity of 35 ppt.  He suggested that Lophelia pertusa was restricted to depths of greater than 70 m by the temperature and salinity, competition from other epifauna (e.g. sponges and sea anemones) and possibly by wave action during storms (Roberts, 2002a).

Sensitivity assessment.  Lophelia pertusa is an extremely long lived species, and is found in deep water where it is isolated from naturally occurring rapid acute changes in temperature.  Short term temperature fluctuations found within Lophelia pertusa reefs have been recorded at 1 -2 °C.  A decrease in temperature to the level of the benchmark is likely to stress the organisms.  There is no empirical evidence of the effect of temperature changes at the level of the benchmark.  However, our knowledge of the conditions within which Lophelia pertusa are found suggests that it would be removed from optimum conditions and thus may suffer negative impacts.  Death of the coral polyps themselves would not immediately result in loss of the reef and the associated species.  The associated species, especially epifauna would be lost over a period of years as the coral matrix was slowly eroded to coral rubble and eventually sediment.  Although Lophelia pertusa may be able to colonize the substratum in the meantime, it would still take many years to replace the original reef (see additional information below).  A resilience of ‘Low’ has been given with a resistance of ‘Very Low’ so that  sensitivity is ‘High’.  

Low Very Low High
Q: Medium
A: Medium
C: Medium
Q: High
A: High
C: High
Q: Medium
A: Medium
C: Medium

Lophelia pertusa occurs in waters of 35 -37 psu but in fjords tolerates salinities as low as 32 psu (Rogers, 1999; Mortensen et al., 2001).  However, Rogers (1999) regarded Lophelia pertusa to be stenohaline.  The Lophelia pertusa reef and its associated fauna occur in relatively stable waters, which are not subject to fluctuations in salinity.  While Lophelia pertusa is probably highly intolerant of changes in salinity at the benchmark level, it is unlikely to experience an increase in salinity except is rare cases such as the unlikely production of hypersaline effluents by offshore installations. 

Sensitivity assessment.  Due to the highly stable conditions in which Lophelia pertusa is usually found a change in salinity is likely to cause mortality of the coral polyps.  Consequently, a resistance has been assessed as ‘Low’, giving a resilience of ‘Very low’, which gives the biotope a sensitivity of ‘High’..

Low Very Low High
Q: High
A: Medium
C: Medium
Q: High
A: High
C: High
Q: Medium
A: Medium
C: Medium

Lophelia pertusa occurs in waters of 35 - 37 psu but in fjords tolerates salinities as low as 32 psu (Rogers, 1999; Mortensen et al., 2001).  However, Rogers (1999) regarded Lophelia pertusa to be stenohaline.  The Lophelia pertusa reef and its associated fauna occur in relatively stable waters, which are not subject to fluctuations in salinity.  While Lophelia pertusa is probably highly intolerant of changes in salinity at the benchmark level, it is unlikely to experience an increase in salinity except is rare cases such as the unlikely production of hyposaline effluents by offshore installations.  However, in shallow fjordic water Lophelia pertusa is restricted to the deeper, stable oceanic water below the relatively reduced salinity coastal waters at the surface.  An increase in freshwater runoff, may increase the depth of the pycnocline and would probably result in death of the upper extent of the reef.

Sensitivity assessment.  Resistance has been assessed as ‘Low’ and resistance as ‘Very Low’, which results in an overall sensitivity at the level of the bench of ‘High’ intermediate has been recorded. 

High High Not sensitive
Q: High
A: High
C: Medium
Q: High
A: High
C: High
Q: High
A: High
C: Medium

Early records of cold-water coral reefs are associated with strong water flows (Roberts et al., 2009).  Further investigation found that Lophelia pertusa reefs occur where the topography causes current acceleration, e.g. on raised seabed features (e.g. seamounts and banks) and where the channel narrows in Norwegian fjords (Rogers, 1999).  Higher water flow rates are thought to aid the two dominant food supply mechanisms to Lophelia pertusa (Roberts et al., 2009).  The two mechanisms are; the regular rapid down welling of surface water delivering pulses of warm nutrient rich surface water, and, the periodic advection of high turbidity bottom waters (Roberts et al., 2009).  Frederiksen et al. (1992) suggested that topographical highs create internal waves that re-suspended organic particulates from the seabed, and increase the flux of nutrient-rich waters to the surface waters increasing phytoplankton productivity; both effects resulting in increased food availability for Lophelia pertusa and other suspension feeders.

Mortensen (2001) investigated the growth and behaviour of Lophelia pertusa in an aquarium with flowing seawater.  No polyp mortality was observed in the vicinity of his aquaria inlets but high mortality at the opposite end.  Similarly, the death of coral polyps within a coral coppice was thought to be due to reduced water flow within the colony (Wilson, 1979b).  Mortensen (2001) also noted that high current flow (greater than ca 0.05 m/s) was detrimental to growth, presumably due to reduced food capture rates.  Frederiksen et al. (1992) suggested that Lophelia pertusa reefs around the Lousy and Hatton Banks would typically encounter currents speeds of 0.01-0.1 m/s.  Water flow rates >0.4 m/s were recorded by moored and landed deployed current meters close to deep-water coral mounds in the Porcupine Seabight (Grehan et al., 2003), while Masson et al. (2003) recorded a maximum residual bottom water flow of 0.35 m/s over a 20 day period in July 2000 over the Darwin Mounds.  The mass movement of water and food availability may be of greater importance than current speed alone.  Currents speeds of 0.01 -0.1 m/s, 0.35 or 0.4 m/s approximate to between weak and moderately strong water flow.  However, oceanic and tidal currents in the region of the Faroes were reported to be about 0.5 m/s (moderately strong) and in the region of west Shetland 0.5 -0.7 m/s or more (moderately strong).  Purser et al. (2010) collected samples of Lophelia pertusa from the Tisler reef off Norway.  They then kept them in controlled laboratory aquaria and tested the effect of flow velocity on food capture rates.  Flow rates were kept at 0.025 m / s and 0.05 m / s, and the reduction in Artemia salina nauplii concentrations were recorded.  It was found that maximum net capture rates were found at the 0.025 m / s rate (Purser et al., 2010).

Sensitivity assessment.  Lophelia pertusa relies on constant, mass water flow to supply food and nutrients.  A decrease in water flow would reduce the availability of food to the reef, which may decrease the health of the Lophelia pertusa colony.  If it were reduced below a certain level, mortality would occur.  Although Lophelia pertusa relies on water flow, Mortensen's data (2001) suggests a sustained water flow over 0.05 m / s may reduce growth.  Areas in which Lophelia pertusa reefs are found experience great changes in water flow rates throughout the tidal cycle.  As long as the increase in water flow rate did not mean that water flow rates were permanently above 0.05 m / s, the pressure at the benchmark is unlikely to have a negative impact on the biotope.  Therefore, both resistance and resilience have been assessed as ‘High’, which results in a sensitivity assessment of ‘Low’.  Any further increase in water flow above the benchmark is likely to cause an impact to the Lophelia pertusa. 

Not relevant (NR) Not relevant (NR) Not relevant (NR)
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR

Lophelia pertusa do not occur in the intertidal, they occur in oceanic waters, at depths of over 200 m, except in Norwegian fjords where it upper depth limit may be 50 m, below the influence of coastal waters.  Therefore, it is unlikely to be affected by changes in the emergence regime and not relevant has been recorded.  The assessment for this biotope at the pressure benchmark is ‘Not relevant’.

Not relevant (NR) Not relevant (NR) Not relevant (NR)
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR

Offshore Lophelia pertusa reefs occur, by definition, in extremely wave exposed conditions, although wave action is ameliorated by depth.  Draper (1967) noted that wave periods in offshore areas are generally of longer than in enclosed seas and therefore penetrates to greater depths.  However, Draper (1967) estimated that as far out as the continental shelf, for one day a year, storm conditions could generate a oscillatory water movement on the seabed of only ca 0.4 m/s at 180 m.  In Norwegian fjords where Lophelia pertusa reefs occur as shallow as 50 m, wave action is slight at the surface and most likely does not penetrate more than a few tens of metres.  Inner fjords have limited fetch so that wave action is unlikely to penetrate to more than a few tens of metres even in storm conditions (Dr Keith Hiscock pers. comm.).

The oscillatory water movement generated by wave action could potentially result in fragmentation of branching coral skeletons at the upper limit of their depth distribution, although their skeletons are fairly robust.  Occasional fragmentation may not unduly affect the reef but allow it to spread in the long term as the fragments continue to grow, or provide a substratum for colonization by Lophelia pertusa larvae.  However, Lophelia pertusa occurs at depths at which even the wave action generated by storm conditions is unlikely to penetrate.  Therefore, ‘Not relevant’ has been recorded.

Chemical Pressures

 ResistanceResilienceSensitivity
Not relevant (NR) Not relevant (NR) Not sensitive
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR

Not sensitive at the pressure benchmark of compliance with all relevant environmental protection standards.

Not relevant (NR) Not relevant (NR) Not sensitive
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR

Not sensitive at the pressure benchmark of compliance with all relevant environmental protection standards.

Not relevant (NR) Not relevant (NR) Not sensitive
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR

Not sensitive at the pressure benchmark of compliance with all relevant environmental protection standards.

No evidence (NEv) Not relevant (NR) No evidence (NEv)
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR

No evidence.

Not relevant (NR) Not relevant (NR) Not sensitive
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR

Not sensitive at the pressure benchmark that assumes compliance with all relevant environmental protection standards.

Low Very Low High
Q: High
A: High
C: Medium
Q: High
A: High
C: High
Q: High
A: Medium
C: Medium

It has been suggested that the lower limit of Lophelia pertusa's bathymetric distribution is partially determined by the oxygen minimum zone (Freiwald, 1998; Rogers, 1999).  Roberts et al. (2003) suggested the lower depth limit of Lophelia pertusa's distribution in the northeast Atlantic was related to temperature.  It is likely to be a combination of factors which determine the distribution of Lophelia pertusa (Davies et al., 2008; Roberts et al., 2009). 

Dodds et al. (2007) investigated the metabolic tolerance of Lophelia pertusa to temperature and dissolved oxygen change.  They found that Lophelia pertusa could survive anoxia for 1 hour, and hypoxia for 96 hours.  The critical oxygen concentration for Lophelia pertusa within its environment was reported as 3.26 ml/l below which concentration the organism wouldn’t be able to carry out normal aerobic function (Dodds et al., 2007).  Davies et al. (2008) mapped the suitable habitat for Lophelia pertusa and found that in the North East Atlantic this organism is associated with areas with an ambient oxygen concentration between 4.62 – 7.39 ml/l.  Both Dodds et al. (2007) and Davies et al. (2008) studied the effects of oxygen concentration on Lophelia pertusa from the North East Atlantic, where the mean oxygen concentration is 6.10 ml/l.  Lunden et al. (2014) studied, among other things, the effect of decreasing oxygen concentration of Lophelia pertusa collected from the Gulf of Mexico.  Oxygen concentrations within the Gulf of Mexico are lower than those recorded in the North East Atlantic, with records ranging from 1.5 – 3.2 ml 1-1 (Lunden et al., 2014).  Laboratory experiments were used to expose Lophelia pertusa to different oxygen concentrations for 7 days.  Oxygen concentrations below 1.5 ml 1-1 were found to cause 100% mortality within their sample.  In response to low oxygen concentrations Lophelia pertusa is able to increase its uptake of oxygen by expansion of the surface area of its polyp, Dodds et al. (2007).

Sensitivity assessment.  The information used to assess this pressure is given in ml / l, but the benchmark level is given in mg / l.  The conversion for dissolved oxygen from mg to ml in fresh water is 10 ml / l to 13.3 ml / l.  At the level of the benchmark it is unlikely the conversion rate will change the outcome of the assessment.  This biotope will be found within the North East Atlantic, and therefore the evidence provided by those studies which have used samples collected within this area is most relevant.  A change in oxygen concentration at the benchmark has the potential to cause significant mortality within certain areas of the North East Atlantic.  Although the mean oxygen concentration within this area is 6.10 ml 1-1 if the mean oxygen concentration within a certain biotope is lower than this and this causes oxygen levels to fall below 3.26 ml 1-1 then 100% mortality could occur within the area. Therefore, resistance is assessed as ‘Low’, and resilience is assessed as ‘Very low, so that  sensitivity assessment is probably ‘High’.

No evidence (NEv) Not relevant (NR) No evidence (NEv)
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR

Information concerning the effects of nutrient levels on Lophelia pertusa and its associated community could not be found.  As a result of this a sensitivity assessment of ‘No evidence’ has been given. 

No evidence (NEv) Not relevant (NR) No evidence (NEv)
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR

Information concerning the effects of nutrient levels on Lophelia pertusa and its associated community could not be found.  As a result of this a sensitivity assessment of ‘No evidence’ has been given. 

Physical Pressures

 ResistanceResilienceSensitivity
None Very Low High
Q: High
A: High
C: High
Q: High
A: High
C: High
Q: High
A: High
C: High

All marine habitats and benthic species are considered to have a resistance of ‘None’ to this pressure and to be unable to recover from a permanent loss of habitat (resilience is ‘Very Low’).  Sensitivity within the direct spatial footprint of this pressure is therefore ‘High’.  Although no specific evidence is described confidence in this assessment is ‘High’, due to the incontrovertible nature of this pressure.

None Very Low High
Q: High
A: High
C: High
Q: High
A: High
C: High
Q: High
A: High
C: High

Lophelia pertusa larvae must settle onto hard substrata (Roberts et al., 2009) to enable then to find a solid anchor point, from which the hard skeleton of the coral can attach.  The presence of Lophelia pertusa on oil and gas platforms (Gass & Roberts, 2006), suggests that their larvae are able to settle onto artificial substrata.  There is no information available on the preference of Lophelia pertusa larvae for certain types of hard substrata.  However, for a change in substrata to occur, the original substratum would need to be removed first, which would result in removal of living coral and dead coral debris, resulting in destruction of the reef and loss of the biotope. 

Sensitivity assessment.  Therefore, a resistance of ‘None’ and a resilience of ‘Very Low’ have been recorded, resulting in a sensitivity of ‘High’.

Not relevant (NR) Not relevant (NR) Not relevant (NR)
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR

Lophelia pertusa larvae have to settle onto a hard substratum.  The branching nature of this reef forming species means that their structures can extend out over soft substrate.  However, as this species requires a hard substratum onto which to anchor, a change in soft sediment type is Not relevant to this biotope.  Hence, the pressure is assessed as ‘Not relevant’. 

None Very Low High
Q: High
A: High
C: High
Q: High
A: High
C: High
Q: High
A: High
C: High

Lophelia pertusa larvae have to settle onto a hard substrata.  However, a large reef may grow out over soft sediment, from which sediment may be extracted.  The reef structure can also significantly change the water flow rates, which can mean that sediment being carried in suspension, is deposited in the reef.  Extraction of substratum to 30 cm within this biotope would mean that all of the reef forming, characterizing species, Lophelia pertusa, would be removed.  This would entirely destroy the habitat and would result in the loss of the biotope.

Sensitivity assessment.  Lophelia pertusa, and the biotope have no resistance the removal of substratum to 30 cm, therefore, the resistance is assessed as ‘None’.  The extremely long lived nature and slow growth rate of the characterizing species Lophelia pertusa means that resilience is ‘Very Low’, giving this biotope an overall sensitivity assessment of ‘High’.

None Very Low High
Q: High
A: High
C: High
Q: High
A: High
C: High
Q: High
A: High
C: High

Although Lophelia pertusa reefs occur at great depths, they are likely to be subject to physical disturbance due to anchorage or positioning of offshore structures on the seabed but especially due to deep-sea trawling.  Rogers (1999) suggested that trawling gear would break up the structure of the reef, fragment the reefs, and potentially result in complete disintegration of the coral matrix, and loss of the associated species.

Fosså et al. (2002) documented and photographed the damage caused to west Norwegian Lophelia pertusa reefs by trawling activity (see Fosså, 2003 for photographs).  They reported that four, out of five sites studied, contained damaged corals. In the shallow regions of Sørmannsneset, only fragments of dead Lophelia pertusa were seen, spread around the site with no evidence of living colonies in the surrounding area, and Fosså et al. (2002) concluded that the colonies had been "wiped out".  Overall, they estimated that between 30 and 50% of Lophelia pertusa reefs were either impacted or destroyed by bottom trawling in western Norway.  Mechanical damage by fishing gear would also damage or kill the associated epifaunal species,  potentially turn over the coral rubble field, and modify the substratum (Rogers, 1999; Fosså et al., 2002).  Fosså et al. (2002) demonstrated that gorgonian (horny) corals were also torn apart by bottom trawling.  Fosså (2003) also note that fixed fishing nets, e.g. gill nets, and long-line fisheries and their associated anchors could potentially result in damage to the reefs such as breakage of the coral colonies.  However, damage by long-line or gill net fisheries is probably of limited extent compared to bottom trawling (Fosså, 2003).  Hall-Spencer et al. (2002) also provided photographic evidence of an area of reef impacted by bottom trawling, with a clearly visible trench (5 -10 cm deep) made by otter boards surrounded by smashed coral fragments in west Norway.  Hall-Spencer et al. (2002) also noted that otter trawling with rockhopper gear damaged coral habitats in west Ireland, based on analysis of by-catch but also noted that fishing vessels actively avoided rough ground and that the majority of trawls did not result in Lophelia pertusa by-catch.  Koslow et al. (2001) reported that on shallow, heavily fished seamounts off Tasmania, trawling had effectively removed the dominant cold-water coral and its associated fauna.  The substratum of heavily fished seamounts was primarily bare rock or coral rubble and sand, features not seen on any lightly fished or un-fished seamount.  The abundance and richness of benthic fauna was also "markedly reduced" on heavily fished seamounts (Koslow et al. (2001).

Sensitivity assessment.  Overall, there is significant evidence of damage to Lophelia pertusa and other cold-water coral reefs due to deep-sea trawling.  Resistance is assessed as ‘None’, and resilience is ‘Very Low’, giving the biotope a sensitivity of ‘High’.

None Very Low High
Q: High
A: High
C: High
Q: High
A: High
C: High
Q: High
A: High
C: High

Penetration and or disturbance of the substratum would result in similar, if not identical results as Abrasion or removal of a Lophelia pertusa reef and its associated community (see abrasion / disturbance).

Sensitivity assessment.  A resistance of ‘None’ has been given.  If the substratum is either penetrated or disturbed, then the overlying reef would also be affected.  The extremely long lived and slow growing nature of Lophelia pertusa, the characterizing species within this biotopes, means that damage incurred would take an extremely long time to recovery.  Therefore, resilience has been assessed as ‘Very Low’ resulting in sensitivity being ‘High’.

Low Very Low High
Q: High
A: High
C: Medium
Q: High
A: High
C: High
Q: High
A: Medium
C: Medium

A change in suspend solids can have two major effects on a biotope.  The firstly being that a change in suspended solids can change the levels of light attenuation, and therefore the amount of light which will reach the biotope.  However, this biotope is found outside of the photic zone within the North East Atlantic and therefore this is not a consideration.  The second effect of a change in suspended solids is the supply of food to the biotope.  The characterizing species, Lophelia pertusa, is a filter feeding organism and relies on the supply of suspended organic matter for sustenance. 

The location of Lophelia pertusa reefs is determined by a multitude of factors, however, a combination of water flow and seafloor relief are important in regards to the supply of food particles and larvae (Flach & Thomsen 1998; Gage et al. 2000; Hughes & Gage, 2004).  Reefs are found in areas where the topography works to accelerate near-bed currents which enhance food supply (Mortensen et al., 2001; Thiem et al., 2006; Kiriakoulakis et al., 2007; Davies et al., 2009).  

Davies et al., (2009) measured the turbidity of the water along a transect within the Mingulay reef complex off the west coast of Scotland.  Turbidity levels varied along the transect, however, on the sections of the transect that were closer to the top of the reef the lower the turbidity levels appeared to be during the onset of an ebb tide (Davies et al., 2009).  Increased turbidity was found to correlate with an increase in the speed of water flow, therefore, throughout the space of one tide there was considerable variation with the levels of suspended solids within the water column.  This information suggests that over a short time period Lophelia pertusa and their associated species can tolerate changes in suspended solids. 

Brooke et al. (2009) compared the tolerance of two morphotypes of Lophelia pertusa (gracilis, fragile; brachcephala, heavily calcified) to different levels of turbidity.  The fragments collected from the Gulf of Mexico were kept in aquaria, at five different turbidity levels, for 14 days.  Both morphotypes of Lophelia pertusa found in clear conditions (<10 mg / l) had 100% survival rates.  Over 80% of Lophelia pertusa kept at intermediate turbidity conditions (10 – 100 mg / l) survived.  Two of the experimental turbidity’s fell within the medium turbidity water frame directive (WFD) ranking system, these were 103 mg / l and 245 mg / l.  In the former both morphotypes had a survival rate of >50%, and the later had a survival rate of >30 %.  Within the very turbid category the more fragile morphotype, gracilis, experienced 100% mortality, and brachycephala had an extremely low survival rate (Brooke et al., 2009).  From the results of this laboratory experiment Brooke et al. (2009) summarized that Lophelia pertusa survival decreased in steps, rather than a continuous linear decline; suggesting that the corals have physiological thresholds beyond which they unable to cope with turbidity levels, at which point mortality can occur.  It must also be determined from this experiment that exposure to an increase in turbidity for over a year would be a long time for Lophelia pertusa.

Mortensen (2001) found that when both food and sediment were presented to Lophelia pertusa at the same time sediment was ingested, however, the process of feeding and polyp cleaning do not occur at the same time (Brooke et al., 2009).  An increase in turbidity with the Lophelia pertusa environment would lead to more settlement of sediment onto the coral polyps.  This would lead to an increase in the amount of time required to remove the sediment from the polyp, which could restrict the amount of time available for feeding.  Brooke et al. (2009) suggested that this could lead to the starvation of the coral polyp even though food may be available.

A decrease in the levels of suspended material at the level of the benchmark would lead to a reduction in the availability of food to Lophelia pertusa, and other filter feeding organisms within the biotope.  Empirical evidence on the amount of food required by Lophelia pertusa is not available, and information from JNCC core records are lacking on the levels of suspended sediment normally experienced within this biotope.  Therefore, it is not possible to determine if there would be any affect at the level of the benchmark.

Sensitivity assessment.  There is no information regarding the level of turbidity normally found within this biotope From the information available an increase in turbidity from clear to intermediate, or intermediate too high for a year could cause significant mortality of Lophelia pertusa.  It is unclear how a decrease in turbidity may affect Lophelia pertusa.  Resistance is assessed as ‘Low’, and resilience is assessed as ‘Very low’, giving a sensitivity of ‘High’.

Medium Very Low Medium
Q: High
A: High
C: Medium
Q: High
A: High
C: High
Q: High
A: Medium
C: Medium

Rogers (1999) suggested that Lophelia pertusa would be intolerant of increased rates of sedimentation, caused by decreased water flow, or the resuspension and subsequent sedimentation of sediment by marine activities, such as offshore construction or mobile fishing gear (e.g. beam or otter trawls), or the discharge of drill cuttings An increase in sedimentation is thought to be one of largest sources of degradation of coral reefs (Norse, 1993) and may suppress the growth rates of Lophelia colonies (Fosså et al., 2002).  Rogers (1999) suggested that sedimentation rates of >10 mg/cm²/day in shallow water coral reefs were high.  Smothered polyps would be expected to starve.

Mortensen (2001) reported that 25-100% of polyps died after being starved for 3 months or more but in some cases polyps survived starvation for 16 and 20 months.  Preliminary results suggest that sand deposition rates of 0.1 mg/cm²/min significantly reduced polyp expansion in Lophelia pertusa (Roberts & Anderson, 2002b), which would reduce feeding and hence growth rates.  Mortensen (2001) demonstrated that Lophelia pertusa was able to remove sediment particles <3 mm within 3-5 min and 3-5 mm particles within ca 15 min due to beating of cilia towards the tips of the tentacles, and reported that the living coenosarc (coral tissue) was always clean of sediment.  Earlier studies by Shelton (1980), showed that Lophelia pertusa could remove graphite particles within ca 30 sec.  Similarly, Reigl (1995) demonstrated that scleractinian corals were able to clean sand from their surface actively.  When exposed to 200 mg of sand per cm² in a single application, scleractinian corals cleared 50% of the sand within 1000 min, and all the species studied survived for 6 weeks continuous exposure to 200 mg of sand per cm².  Reigl (1995) concluded that corals could cope with considerable amounts of sand deposition.  Nevertheless, Rogers (1999) suggested that an increase in sedimentation is likely to interfere with feeding and hence growth, which would alter the balance between growth and bioerosion, potentially resulting in degradation of the reef.  In addition, smothering would prevent settlement of larvae and hence recruitment.

Dodds et al. (2007) found that Lophelia pertusa can change its metabolic rate in accordance with oxygen availability.  Allers et al. (2013) investigated the resilience of Lophelia pertusa taken off Norway to sedimentation in laboratory based experiments.  They found that both the mucus production and branching morphology of Lophelia pertusa accumulation of sediment is relatively slow.  Short term (<24 hours) exposure to sedimentation reduced the availability of oxygen to Lophelia pertusa.  However, the organism could tolerate both low-oxygen and anoxic conditions without suffering visible, short term effects (Allers et al., 2013).  But complete burial for >24 hours caused suffocation and mortality (Allers et al., 2013).  As little as 3 mm of sediment covering a Lophelia pertusa can lead to complete anoxia within six days, and the thicker the covering of sediment the faster anoxia occurs (Allers et al., 2013).  Brooke et al. (2009) reported different tolerance of Lophelia pertusa  to total burial.  Samples of Lophelia pertusa were collected from the Gulf of Mexico, and tested for their tolerance to complete burial in sediment.  It was found that a significant tolerance threshold was reached between 2 – 4 days, after which time very low survival rates were recorded (Brooke et al., 2009).

Sensitivity assessment.  At the benchmark level the majority of the Lophelia pertusa polyps would probably be unaffected due to the size of the colony, which is raised above the seabed.  The levels of water flow within this environment are recorded as significant, therefore, it is likely that the sediment would be re-suspended, and removed relatively quickly.  However, if the sediment were to remain for more than two days then it is likely that any polyps which were buried would suffer mortality.  Resistance of this biotope to the pressure at the benchmark is assessed as ‘Medium’ and resilience is assessed as ‘Very low’, giving the biotope a sensitivity of ‘Medium’. 

Low Very Low High
Q: High
A: Medium
C: Medium
Q: High
A: High
C: High
Q: High
A: Medium
C: Medium

Using the information within provided for the ‘light’ smothering and siltation pressure, it can be assumed that the burial of Lophelia pertusa in 30 cm of sediment would cause considerable damage to the health of this reef forming species.  If the sediment were to remain in place for more than two days, any buried polyps are likely to have suffered mortality.

Sensitivity assessment.  At the pressure benchmark, this biotope is assessed to have a ‘Low’ resistance, the resilience is assessed as ‘Very low’, giving an overall sensitivity of ‘High’. 

Not Assessed (NA) Not Assessed (NA) Not assessed (NA)
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR

No evidence.

No evidence (NEv) Not relevant (NR) No evidence (NEv)
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR

No evidence.

Not relevant (NR) Not relevant (NR) Not relevant (NR)
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR

Species characterizing this habitat do not have hearing perception but vibrations may cause an impact, however, no studies exist to support an assessment.

No evidence (NEv) Not relevant (NR) No evidence (NEv)
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR

Natural light rarely penetrates to the depth this biotope is found within the North East Atlantic.  Therefore, an increase in the amount of natural light is ‘Not relevant’ to this biotope.  However, due to the oil and gas platforms and other forms of exploration or removal of resources it is possible that un-natural light could be introduced to this biotope.  There is no evidence to support an assessment at this pressure benchmark though, and consequently an assessment of ‘No evidence’ has been given.

Not relevant (NR) Not relevant (NR) Not relevant (NR)
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR

Not relevant – this pressure is considered applicable to mobile species, e.g. fish and marine mammals rather than seabed habitats. Physical and hydrographic barriers may limit propagule dispersal.  But propagule dispersal is not considered under the pressure definition and benchmark.

Not relevant (NR) Not relevant (NR) Not relevant (NR)
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR

Not relevant – this pressure is considered applicable to mobile species, e.g. fish and marine mammals rather than seabed habitats. Physical and hydrographic barriers may limit propagule dispersal.  But propagule dispersal is not considered under the pressure definition and benchmark.

Not relevant (NR) Not relevant (NR) Not relevant (NR)
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR

Not relevant.

Biological Pressures

 ResistanceResilienceSensitivity
Not relevant (NR) Not relevant (NR) Not sensitive
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR

This pressure is not relevant to the characterizing species within this biotope.  Therefore, an assessment of ‘Not relevant’ has been given. 

Not relevant (NR) Not relevant (NR) Not sensitive
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR

No alien or non-native species are known to compete with Lophelia pertusa or other cold-water corals.  As a result of this a sensitivity assessment of ‘No relevant’ has been given.

No evidence (NEv) Not relevant (NR) No evidence (NEv)
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR
Q: NR
A: NR
C: NR

No information on diseases was found.  However, the parasitic foraminiferan Hyrrokkin sarcophaga was reported growing on polyps of Lophelia pertusa in aquaria (Mortensen, 2001).  The foraminiferan dissolves a hole in the coral skeleton and invades the polyp.  In his aquaria, two Lophelia pertusa polyps became infested but did not seem to be influenced by the infestation (Mortensen, 2001).  Any parasitic infestation is likely to reduce the viability of the host, even if only a few or possibly hundreds of polyps were affected but in the absence of additional evidence as assessment of ‘No evidence’ has been given. 

High High Not sensitive
Q: Medium
A: Medium
C: Medium
Q: Medium
A: Medium
C: Medium
Q: Medium
A: Medium
C: Medium

Lophelia pertusa is not directly targeted by a commercial fishery.  However, with the advent of deep-water fisheries, the habitats within which Lophelia pertusa is found have been heavily targeted by deep-water fishing trawlers because of their high biodiversity.

None of the species that are targeted by the commercial fishery have known symbiotic relationships.  The only known species with which Lophelia pertusa has a symbiotic relationship with is the Polychaete Eunice norvegica (Mueller et al., 2013).

Sensitivity assessment.  The biological impact of the removal of species associated with Lophelia pertusa, is not thought to have a negative impact on this biotope.  Consequently resistance and resilience are assessed as ‘High’, resulting in an sensitivity assessment of ‘High’.

None Very Low High
Q: High
A: High
C: Medium
Q: High
A: Medium
C: High
Q: High
A: Medium
C: Medium

Extraction of Lophelia pertusa colonies from the reef would result in fragmentation of the coral, and destruction of the reef structure.  The development of larger vessels and more powerful trawls, e.g. rockhopper gear designed to operate on rough stony bottoms, has probably exposed the reefs to increased impacts from fishing (Fosså et al., 2002; Fosså, 2003).  For example, the fishery of the continental break targeted Greenland halibut, redfish, and saithe.  The orange-roughy is another valuable deep-sea species associated with offshore banks, pinnacles and canyons with strong currents, which are favoured by Lophelia pertusa (Rogers, 1999).  In the UK, monkfish is a major fishery in the vicinity of the Lophelia pertusa reefs around Rockall (Dr Jason Hall-Spencer, pers comm.). 

 

Demersal fishing operations have been shown to have a significant negative impact on Lophelia pertusa reefs within the North-east Atlantic.  Unequivocal evidence for the physical damage of bottom trawling in cold-water habitats has been presented for many areas around the world (Roberts et al., 2009), including areas within the North East Atlantic.  Fosså et al. (2002) used remotely operated vehicles to survey areas of cold-water coral reefs of the west coast of Norway.  They described areas historically known cold-water coral reefs, containing Lophelia pertusa, to show only scattered coral fragments or crushed and broken coral skeletons.  When their findings were extrapolated it was estimated that between 30 – 50% of Lophelia pertusa reefs from Norway had been damaged by trawling (Fosså et al., 2002).  Hall-Spencer et al. (2002) found that cold-water coral reefs containing Lophelia pertusa off the West Ireland continental shelf break were being damaged by commercial trawls for deep-water fish.  Coral aged to be at least 4500 years old, was being removed from reefs as by-catch.  Grehan et al. (2004) collected imagery data from cold-water coral reefs containing Lophelia pertusa off the West Ireland continental shelf break and West Norway.  They found widespread damage caused by trawling to cold-water coral reefs within these geographical areas.

Trawling can also re-suspend seabed sediments and cause further damage to the habitat through smothering (see smothering pressure).  Trawling experiments in the Mediterranean found that water-column turbidity increased by as much as three times for five days after a trawling event (Palanques et al., 2001; taken from Roberts et al., 2009).  At the time of writing no evidence is available on the impact of re-suspended sediment caused by trawling, the radius of its effects on Lophelia pertusa, or the effects on the associated species. 

Sensitivity assessment. Removal of a large percentage of the characterizing species would alter the character of the biotope. The resistance to removal is ‘None’  due to the easy accessibility of the biotopes location and the inability of these species to evade collection. The resilience is ‘Very low’, with recovery only being able to begin when the harvesting pressure is removed altogether. This gives an overall sensitivity score of ‘High’.

Importance review

Policy/Legislation

Habitats of Principal ImportanceCold-water coral reefs [Scotland], Cold-water coral reefs [Scotland]
Habitats of Conservation ImportanceCold-water coral reef, Cold-water coral reef
Habitats Directive Annex 1Reefs, Reefs
OSPAR Annex VLophelia pertusa reefs, Lophelia pertusa reefs
Priority Marine Features (Scotland)Cold-water coral reefs, Cold-water coral reefs
UK Biodiversity Action Plan PriorityCold-water coral reefs

Exploitation

Lophelia reefs are not exploited directly but occur in areas subject to deep sea fishing (Rogers, 1999; Fosså et al., 2002; Hall-Spencer et al., 2002). The decline of traditional fisheries (e.g. cod) has resulted in increased interest in deep-sea species since the late 1980s (Rogers, 1999). Reefs are considered to be good fishing places for net and long-line fisheries, and fishermen often set their gear as close as possible to reefs but not on them to avoid damaging their fishing gear. However, the development of larger vessels and more powerful trawls, e.g. rockhopper gear designed to operate on rough stony bottoms, has probably exposed the reefs to increased impacts from fishing (Fosså et al., 2002). For example, the fishery of the continental break targeted Greenland halibut, redfish, and saithe. The orange-roughy is another valuable deep-sea species associated with offshore banks, pinnacles and canyons with strong currents, which are favoured by Lophelia (Rogers, 1999). In the UK, monkfish is a major fishery in the vicinity of the Lophelia reefs around Rockall (Dr Jason Hall-Spencer, pers comm.). Major fisheries in the vicinity of the 'Darwin Mounds' include deep-water demersal trawls for blue ling, orange roughy with a by-catch of black scabbard fish, Portuguese dogfish and leaf-scale gulper shark, long-lining for hake and deep-water sharks, and semi-pelagic trawling for blue whiting and argentine (Gubbay et al., 2002).

The potential effects of deep-sea fishing on the seabed and deep-water coral reefs has become a major concern (Rogers, 1999; Fosså et al., 2002; Hall-Spencer et al., 2002; Grehan et al., 2003). Photographic evidence of the effects of trawling damage, long line or fixed net fisheries, and discards on Lophelia reefs is shown in Fosså et al. (2002); Hall-Spencer et al., (2002) and Fosså (2003).

Additional information

Evidence of damage to their cold-water coral reefs prompted Norway to designate its most important Lophelia reefs as marine reserves recently and ban towed-gear fisheries from them (Johnston & Tasker, 2002). Similarly, both Australia and New Zealand have created a network of seamount protected areas (Grehan et al., 2003). Grehan et al. (2003) found no evidence of trawl related damage in five deep-water coral locations in the Irish Porcupine Seabight and the Rockall Trough and suggested that these sites should be subject to protection urgently, especially in the light of the expanding deep-water fishery for orange-roughy. The 'Darwin Mounds' in the Rockall Trough are probably the most intensively studied cold-water coral reef known in UK waters. The 'Darwin Mounds' have recently been proposed as the first offshore candidate Special Area of Conservation (Johnston & Tasker, 2002). An outline management plan for the 'Darwin Mounds' was proposed by Gubbay et al. (2002). Grehan et al. (2003) noted that deep-water corals: may provide spawning grounds and refugia for juvenile fish of commercial fish species;may be a major source or sink of carbonate;could potentially be a paleo-climate indicator for the study of global climate change;and may be a potential source of novel pharmaceutical compounds. In addition, Hall-Spencer et al. (2002) noted that although all shallow water organisms had accumulated nuclear bomb test related 14C, the Lophelia specimens collected from deep-waters off west Ireland were not contaminated by anthropogenic 14C, presumably because the water bodies they occupy are ancient. Therefore, Lophelia at sites in west Ireland could provide a useful background or baseline level for studies of radioactive contamination.

Bibliography

  1. Allers, E., Abed, R.M., Wehrmann, L.M., Wang, T., Larsson, A.I., Purser, A. & de Beer, D., 2013. Resistance of Lophelia pertusa to coverage by sediment and petroleum drill cuttings. Marine Pollution Bulletin, 74 (1), 132-140.

  2. Althaus, F., Williams, A., Schlacher, T., Kloser, R., Green, M., Barker, B., Bax, N., Brodie, P. & Schlacher-Hoenlinger, M., 2009. Impacts of bottom trawling on deep-coral ecosystems of seamounts are long-lasting. Marine Ecology Progress Series, 397, 279-294.

  3. Anonymous, 1999iv. Lophelia pertusa reefs. In UK Biodiversity Group. Tranche 2 Action Plans. English Nature for the UK Biodiversity Group, Peterborough., English Nature for the UK Biodiversity Group, Peterborough., http://www.ukbap.org.uk/asp/UKPlans.asp?UKListID=45#1

  4. Bell, N. & Smith, J., 1999. Coral growing on North Sea oil rigs. Nature, 402, 601.

  5. Besten, P.J. den, Donselaar, E.G. van, Herwig, H.J., Zandee, D.I. & Voogt, P.A., 1991. Effects of cadmium on gametogenesis in the seastar Asterias rubens L. Aquatic Toxicology, 20, 83-94.

  6. Besten, P.J. den, Herwig, H.J., Zandee, D.I. & Voogt, P.A., 1989. Effects of Cd and PCBs on reproduction in the starfish Asterias rubens: aberrations in early development. Ecotoxicology and Environmental Safety, 18, 173-180.

  7. Bett, B.J., 2000. Benthic survey of the Faeroe-Shetland Channel. [CD-ROM] AFEN (2000) Atlantic margin environmental surveys of the seafloor 1996 and 1998. United Kingdom Offshore Operators Association.

  8. Bett, B.J., 2001. UK Atlantic Margin environmental survey: introduction and overview of bathyal benthic ecology. Continental Shelf Research, 21, 917-956.

  9. Boero, F., 1984. The ecology of marine hydroids and effects of environmental factors: a review. Marine Ecology, 5, 93-118.

  10. Brooke, S. & Järnegren, J., 2013. Reproductive periodicity of the scleractinian coral Lophelia pertusa from the Trondheim Fjord, Norway. Marine Biology, 160 (1), 139-153.

  11. Brooke, S., Holmes, M. & Young, C., 2009. Sediment tolerance of two different morphotypes of the deep-sea coral Lophelia pertusa from the Gulf of Mexico. Marine Ecology Progress Series, 390, 137-144.

  12. Bryan, G.W. & Gibbs, P.E., 1991. Impact of low concentrations of tributyltin (TBT) on marine organisms: a review. In: Metal ecotoxicology: concepts and applications (ed. M.C. Newman & A.W. McIntosh), pp. 323-361. Boston: Lewis Publishers Inc.

  13. Bryan, G.W., 1984. Pollution due to heavy metals and their compounds. In Marine Ecology: A Comprehensive, Integrated Treatise on Life in the Oceans and Coastal Waters, vol. 5. Ocean Management, part 3, (ed. O. Kinne), pp.1289-1431. New York: John Wiley & Sons.

  14. Buhl-Mortensen, L. & Mortensen, P.B., 2005. Distribution and diversity of species associated with deep-sea gorgonian corals off Atlantic Canada. Cold-water corals and ecosystems: Springer, pp. 849-879.

  15. Buhl‐Mortensen, L., Vanreusel, A., Gooday, A.J., Levin, L.A., Priede, I.G., Buhl‐Mortensen, P., Gheerardyn, H., King, N.J. & Raes, M., 2010. Biological structures as a source of habitat heterogeneity and biodiversity on the deep ocean margins. Marine Ecology, 31 (1), 21-50.

  16. Cairns, S.D., 1979. The deep-water Scleractinia of the Caribbean Sea and adjacent waters. Studies on the Fauna of Curaçao and other Caribbean Islands, 57 (1), 1-341.

  17. Cairns, S.D., 1994. Scleractinia of the temperate North Pacific: Citeseer.

  18. Davies, A.J., Duineveld, G.C., Lavaleye, M.S., Bergman, M.J., van Haren, H. & Roberts, J.M., 2009. Downwelling and deep-water bottom currents as food supply mechanisms to the cold-water coral Lophelia pertusa (Scleractinia) at the Mingulay Reef complex. Limnology and Oceanography, 54 (2), 620.

  19. Davies, A.J., Wisshak, M., Orr, J.C. & Roberts, J.M., 2008. Predicting suitable habitat for the cold-water coral Lophelia pertusa (Scleractinia). Deep Sea Research Part I: Oceanographic Research Papers, 55 (8), 1048-1062.

  20. De Forges, B.F., Koslow, J.A. & Poore, G.C.B., 2000. Diversity and endemism of the benthic seamount fauna in the southwest Pacific. Nature, 405, 944-947.

  21. de Mol, B., Van Rensbergen, P., Pillen, S., Van Herreweghe, K., Van Rooij, D., McDonnell, A., Huvenne, V., Ivanov, M., Swennen, R. & Henriet, J.P., 2002. Large deep-water coral banks in the Porcupine Basin, southwest of Ireland. Marine Geology, 188, 193-231.

  22. Dodds, L., Roberts, J., Taylor, A. & Marubini, F., 2007. Metabolic tolerance of the cold-water coral Lophelia pertusa (Scleractinia) to temperature and dissolved oxygen change. Journal of Experimental Marine Biology and Ecology, 349 (2), 205-214.

  23. Draper, L., 1967. Wave activity at the sea bed around northwestern Europe. Marine Geology, 5, 133-140.

  24. Do physical and chemical factors structure the macrobenthic community at a continental slope in the NE Atlantic?

  25. Form, A.U. & Riebesell, U., 2012. Acclimation to ocean acidification during long‐term CO2 exposure in the cold‐water coral Lophelia pertusa. Global Change Biology, 18 (3), 843-853.

  26. Fosså, J.H., 2003. Coral reefs in Norway. [On-line] http://www.imr.no/coral/index.php, 2003-03-27

  27. Fosså, J.H., Mortensen, P.B. & Furevik, D.M., 2002. The deep-water coral Lophelia pertusa in Norwegian waters: distribution and fishery impacts. Hydrobiologia, 471, 1-12.

  28. Frederiksen, R., Jensen, A. & Westerberg, H., 1992. The distribution of the Scleractinian coral Lophelia pertusa around the Faroe Islands and the relation to internal tidal mixing. Sarsia, 77, 157-171.

  29. Freiwald, A., 1998. Geobiology of Lophelia pertusa (Scleractinia) reefs in the North Atlantic. , Habilitation Thesis. Fachbereich Geowissenschaften, Universität Bremen, Bremen, 116 pp.

  30. Freiwald, A., Fosså, J.H., Grehan, A., Koslow, T. & Roberts, J.M., 2004. Cold-water coral reefs. UNEP-WCMC, Cambridge, UK, 84.

  31. Freiwald, A., Henrich, R. & Pätzold, J., 1997. Anatomy of a deep-water coral reef mound from Stjernsund, West Finmark, North Norway. In Cool-water carbonates (ed. N.P. James & J.A.O., Clarke), pp. 141-162. [Society for Sedimentary Geology, Special Volume, no. 56.]

  32. Gage, J.D., Lamont, P.A., Kroeger, K., Paterson, G.L. & Vecino, J.L.G., 2000. Patterns in deep-sea macrobenthos at the continental margin: standing crop, diversity and faunal change on the continental slope off Scotland. Island, Ocean and Deep-Sea Biology: Springer, pp. 261-271.

  33. Gass, S.E. & Roberts, J.M., 2006. The occurrence of the cold-water coral Lophelia pertusa (Scleractinia) on oil and gas platforms in the North Sea: colony growth, recruitment and environmental controls on distribution. Marine Pollution Bulletin, 52 (5), 549-559.

  34. Georgian, S.E., Shedd, W. & Cordes, E.E., 2014. High resolution ecological niche modelling of the cold-water coral Lophelia pertusa in the Gulf of Mexico. Marine Ecology Progress Series, 506, 145-161.

  35. Gili, J-M. & Hughes, R.G., 1995. The ecology of marine benthic hydroids. Oceanography and Marine Biology: an Annual Review, 33, 351-426.

  36. Gommez, J.L.C. & Miguez-Rodriguez, L.J., 1999. Effects of oil pollution on skeleton and tissues of Echinus esculentus L. 1758 (Echinodermata, Echinoidea) in a population of A Coruna Bay, Galicia, Spain. In Echinoderm Research 1998. Proceedings of the Fifth European Conference on Echinoderms, Milan, 7-12 September 1998, (ed. M.D.C. Carnevali & F. Bonasoro) pp. 439-447. Rotterdam: A.A. Balkema.

  37. Grehan, A.J., Unnithan, V., Olu-Le Roy, K. & Opderbecke, J., 2003. Fishing impacts on Irish deep-water coral reefs: making the case for coral conservation. In press

  38. Gubbay, S., Baker, C.M. & Bett, B.J., 2002. The Darwin Mounds and Dogger Bank. Case studies of the management of two potential Special Areas of Conservation in the offshore environment. A report to WWF-UK., 72 pp.

  39. Hall-Spencer, J.M., Allain, V. & Fosså, J.H., 2002. Trawling damage to Northeast Atlantic ancient coral reefs. Proceedings of the Royal Society of London, Series B: Biological Sciences, 269, 507-511.

  40. Henry, L.-A. & Roberts, J.M., 2007. Biodiversity and ecological composition of macrobenthos on cold-water coral mounds and adjacent off-mound habitat in the bathyal Porcupine Seabight, NE Atlantic. Deep Sea Research Part I: Oceanographic Research Papers, 54 (4), 654-672.

  41. Hiscock, K., 1983. Water movement. In Sublittoral ecology. The ecology of shallow sublittoral benthos (ed. R. Earll & D.G. Erwin), pp. 58-96. Oxford: Clarendon Press.

  42. Hoare, R. & Hiscock, K., 1974. An ecological survey of the rocky coast adjacent to the effluent of a bromine extraction plant. Estuarine and Coastal Marine Science, 2 (4), 329-348.

  43. Holt, T.J., Jones, D.R., Hawkins, S.J. & Hartnoll, R.G., 1995. The sensitivity of marine communities to man induced change - a scoping report. Countryside Council for Wales, Bangor, Contract Science Report, no. 65.

  44. Hovland, M. & Mortensen, P.B., 1999. Norske korallrev og prosesser i havbunnen. Bergen: John Grieg forlag.

  45. Hovland, M. & Thomsen, E., 1997. Cold-water corals - are they hydrocarbon seep related? Marine Geology, 137, 159-164.

  46. Hovland, M., Mortensen, P., Brattegard, P., Strass, T. & Kokeongen, K., 1998. Ahermatypic coral banks off Mid-Norway: evidence for a link with seepage of light hydrocarbons. Palaios, 13, 189-200.

  47. Hughes, D. & Gage, J., 2004. Benthic metazoan biomass, community structure and bioturbation at three contrasting deep-water sites on the northwest European continental margin. Progress in Oceanography, 63 (1), 29-55.

  48. ICES, 2002. Study group on mapping the occurrence of cold water corals. Interim Report. Report to the Advisory Committee on Ecosystems of the International Council for the Exploration of the Sea (ICES), ICES CM 2002/ACE:05 Ref: E, WGECO.

  49. Jensen, A. & Frederiksen, R., 1992. The fauna associated with the bank-forming deepwater coral Lophelia pertusa (Scleractinaria) on the Faroe Shelf. Sarsia, 77, 53-69.

  50. Johnston, C. & Tasker, M., 2002. Darwin Mounds proposed Special Area of Conservation. [On-line] http://www.jncc.gov.uk/management/committee/papers02-06/index.htm, 2003-01-29

  51. Jonsson, L.G., Nilsson, P.G., Floruta, F. & Lundaelv, T., 2004. Distributional patterns of macro- and megafauna associated with a reef of the cold-water coral Lophelia pertusa on the Swedish west coast. Marine Ecology Progress Series, 284, 163-171.

  52. Kinne, O. (ed.), 1984. Marine Ecology: A Comprehensive, Integrated Treatise on Life in Oceans and Coastal Waters.Vol. V. Ocean Management Part 3: Pollution and Protection of the Seas - Radioactive Materials, Heavy Metals and Oil. Chichester: John Wiley & Sons.

  53. Kiriakoulakis, K., Fisher, E., Wolff, G.A., Freiwald, A., Grehan, A. & Roberts, J.M., 2005. Lipids and nitrogen isotopes of two deep-water corals from the North-East Atlantic: initial results and implications for their nutrition. Cold-Water Corals and Ecosystems: Springer, pp. 715-729.

  54. Koslow, J.A., Gowlett-Holmes, K., Lowry, J.K., O'Hara, T., Poore, G.C.B. & Williams, A., 2001. Seamount benthic macrofauna off southern Tasmania: community structure and impacts of trawling. Marine Ecology Progress Series, 213, 111-125.

  55. Le Goff-Vitry, M. & Rogers, A.D., 2002. Population structure of deep-sea coral Lophelia pertusa in the north east Atlantic seen through microsatellites. In Proceedings of the International Society for Reef Studies, European Meeting, Cambridge, 4-7 September 2002, abstract of oral presentation.

  56. Loya, Y. & Rinkevich, B., 1980. Effects of oil pollution on coral reef communities. Marine Ecology Progress Series, 3, 167-180.

  57. Lunden, J.J., McNicholl, C.G., Sears, C.R., Morrison, C.L. & Cordes, E.E., 2014. Acute survivorship of the deep-sea coral Lophelia pertusa from the Gulf of Mexico under acidification, warming, and deoxygenation. Frontiers in Marine Science, 1, 78.

  58. Maier, C., 2008. High recovery potential of the cold-water coral Lophelia pertusa. Coral Reefs, 27 (4), 821-821.

  59. Masson, D.G., Bett, B.J., Billet, D.S.M., Jacobs, C.L., Wheeler, A.J. & Wynn, R.B., 2003. The origin of deep-water, coral topped mounds in the northern Rockall Trough, Northeast Atlantic. Marine Geology, 194, 159-180.

  60. Mikkelsen, N., Erlenkauser, H., Killingley, J.S. & Berger, W.H., 1982. Norwegian corals: radiocarbon and stable isotopes in Lophelia pertusa. Boreas, 5, 163-171.

  61. Mortensen, P.B. & Rapp, H.T., 1998. Oxygen and carbon isotope ratios related to growth line patterns in skeletons of Lophelia pertusa (L) (Anthozoa, Scleractinia): Implication for determination of linear extension rates. Sarsia, 83, 433-446.

  62. Mortensen, P.B., 2001. Aquarium observations on the deep-water coral Lophelia pertusa (L., 1758) (Scleractinia) and selected associated invertebrates. Ophelia, 54, 84-104.

  63. Mortensen, P.M., Hovland, M.T., Fosså, J.H. & Furevik, D.M., 2001. Distribution, abundance and size of Lophelia pertusa coral reefs in mid-Norway in relation to seabed characteristics. Journal of the Marine Biological Association of the United Kingdom, 81, 581-597.

  64. Mueller, C.E., Lundälv, T., Middelburg, J.J. & van Oevelen, D., 2013. The symbiosis between Lophelia pertusa and Eunice norvegica stimulates coral calcification and worm assimilation. PLoS ONE, 8 (3), e58660.

  65. Mullins, H.T., Newton, C.R., Heath, K. & Vanburen, H.M., 1981. Modern deep-water coral mounds north of Little Bahama Bank: criteria for recognition of deep-water coral bioherms in the rock record. Journal of Sedimentary Research, 51 (3).

  66. Norse, E.A., 1993. Global marine biological diversity: a strategy for building conservation into decision making. Washington D.C.: Island Press.

  67. Olsgard, F. & Gray, J.S., 1995. A comprehensive analysis of the effects of offshore oil and gas exploration and production on the benthic communities of the Norwegian continental shelf. Marine Ecology Progress Series, 122, 277-306.

  68. Palanques, A., Guillén, J. & Puig, P., 2001. Impact of bottom trawling on water turbidity and muddy sediment of an unfished continental shelf. Limnology and Oceanography, 46 (5), 1100-1110.

  69. Purser, A., Larsson, A.I., Thomsen, L. & van Oevelen, D., 2010. The influence of flow velocity and food concentration on Lophelia pertusa (Scleractinia) zooplankton capture rates. Journal of Experimental Marine Biology and Ecology, 395 (1), 55-62.

  70. Rees, H.L., Waldock, R., Matthiessen, P. & Pendle, M.A., 2001. Improvements in the epifauna of the Crouch estuary (United Kingdom) following a decline in TBT concentrations. Marine Pollution Bulletin, 42, 137-144.

  71. Reigl, B., 1995. Effects of sand deposition on scleractinian and alcyonacean corals. Marine Biology, 121, 517-526.

  72. Richmond, R.H., 1997. Reproduction and recruitment in corals: critical links in the persistence of reefs. In Life and death of coral reefs (ed. C. Birkeland), pp. 175-197. New York: Chapman & Hall.

  73. Ringelband, U., 2001. Salinity dependence of vanadium toxicity against the brackish water hydroid Cordylophora caspia. Ecotoxicology and Environmental Safety, 48, 18-26.

  74. Roberts, J.M., 2009. Cold-water corals: the biology and geology of deep-sea coral habitats. Cambridge University Press.

  75. Roberts, D., Cummins, S., Davis, A. & Chapman, M., 2006. Structure and dynamics of sponge-dominated assemblages on exposed and sheltered temperate reefs. Marine Ecology Progress Series, 321, 19-30.

  76. Roberts, J.M. & Anderson, R., 2003. Laboratory studies of Lophelia pertusa - preliminary studies of polyp behaviour. [On-line] http://www.sams.ac.uk/dml/projects/benthic/lophaqua.htm, 2003-01-29

  77. Roberts, J.M. & Anderson, R.M., 2002. A new laboratory method for monitoring deep-water coral polyp behaviour. Hydrobiologia, 471, 143-148.

  78. Roberts, J.M. & Cairns, S.D., 2014. Cold-water corals in a changing ocean. Current Opinion in Environmental Sustainability, 7, 118-126.

  79. Roberts, J.M., 2002a. The occurrence of the coral Lophelia pertusa and other conspicuous epifauna around an oil platform in the North Sea. Journal for the Society for Underwater Technology, 25, 83-91.

  80. Roberts, J.M., 2002b. Cold water coral, Lophelia pertusa. [On-line] http://www.sams.ac.uk/dml/projects/benthic/lophelia.htm, 2003-01-28

  81. Roberts, J.M., Long, D., Wilson, J.B., Mortensen, P.B. & Gage, J.D., 2003. The cold-water coral Lophelia pertusa (Scleractinia) and enigmatic seabed mounds along the north-east Atlantic margin: are they related? Marine Pollution Bulletin, 46, 7-20.

  82. Rogers, A.D., 1999. The biology of Lophelia pertusa (Linnaeus, 1758) and other deep-water reef-forming corals and impacts from human activities. International Review of Hydrobiology, 84, 315-406.

  83. Rokoengen, K. & Østma, S.R., 1985. Shallow geology off Fedje western Norway. IKU Report, no. 24.1459/01/85.

  84. Ryland, J.S., 1967. Polyzoa. Oceanography and Marine Biology: an Annual Review, 5, 343-369.

  85. Schröder-Ritzrau, A., Freiwald, A. & Mangini, A., 2005. U/Th-dating of deep-water corals from the eastern North Atlantic and the western Mediterranean Sea. In Cold-water corals and ecosystems (eds A. Freiwald & J.M. Roberts, J.M.) pp. 157-172. Berlin: Springer Science & Business Media.

  86. Schroeder, W., 2002. Observations of Lophelia pertusa and the surficial geology at a deep-water site in the northeastern Gulf of Mexico. Hydrobiologia, 471 (1-3), 29-33.

  87. Sebens, K.P., 1985. Community ecology of vertical rock walls in the Gulf of Maine: small-scale processes and alternative community states. In The Ecology of Rocky Coasts: essays presented to J.R. Lewis, D.Sc. (ed. P.G. Moore & R. Seed), pp. 346-371. London: Hodder & Stoughton Ltd.

  88. Sebens, K.P., 1986. Spatial relationships among encrusting marine organisms in the New England subtidal zone. Ecological Monographs, 56, 73-96.

  89. Shelton, G.A.B., 1980. Lophelia pertusa (L.): electrical conduction and behaviour in a deep-water coral. Journal of the Marine Biological Association of the United Kingdom, 60, 517-528.

  90. Smith, J.E. (ed.), 1968. 'Torrey Canyon'. Pollution and marine life. Cambridge: Cambridge University Press.

  91. Soule, D.F. & Soule, J.D., 1979. Bryozoa (Ectoprocta). In Pollution ecology of estuarine invertebrates (ed. C.W. Hart & S.L.H. Fuller), pp. 35-76.

  92. Squires, D.F., 1964. Fossil coral thickets in Wairarapa, New Zealand. Journal of Palaeontology, 38, 904-915.

  93. Thiem, Ø., Ravagnan, E., Fosså, J.H. & Berntsen, J., 2006. Food supply mechanisms for cold-water corals along a continental shelf edge. Journal of Marine Systems, 60 (3), 207-219.

  94. Tursi, A., Mastrototaro, F., Matarrese, A., Maiorano, P. & D'onghia, G., 2004. Biodiversity of the white coral reefs in the Ionian Sea (Central Mediterranean). Chemistry and Ecology, 20 (1), 107-116.

  95. Vella, G., Rushforth, I., Mason, E., Hough, A., England, R., Styles, P, Holt, T & Thorne, P., 2001. Assessment of the effects of noise and vibration from offshore windfarms on marine wildlife. Department of Trade and Industry (DTI) contract report, ETSU W/13/00566/REP. Liverpool: University of Liverpool., Department of Trade and Industry (DTI) contract report, ETSU W/13/00566/REP. Liverpool: University of Liverpool.

  96. Waller, R.G. & Tyler, P.A., 2005. The reproductive biology of two deep-water, reef-building scleractinians from the NE Atlantic Ocean. Coral Reefs, 24 (3), 514-522.

  97. Waller, R.G., 2005. Deep-water Scleractinia (Cnidaria: Anthozoa): current knowledge of reproductive processes. Cold-Water Corals and Ecosystems: Springer, pp. 691-700.

  98. Wheeler, A.J., Beck, T., Thiede, J., Klages, M., Grehan, A., Monteys, F.X. & Polarstern, A., 2005. Deep-water coral mounds on the Porcupine Bank, Irish Margin: preliminary results from the Polarstern ARK-XIX/3a ROV cruise. Cold-water corals and ecosystems: Springer, pp. 393-402.

  99. Wilson, J.B., 1979a. The distribution of the coral Lophelia pertusa (L.) [L. prolifera (Pallas)] in the North-east Atlantic. Journal of the Marine Biological Association of the United Kingdom, 59, 149-164.

  100. Wilson, J.B., 1979b. 'Patch' development of the deep-water coral Lophelia pertusa (L.) on Rockall Bank. Journal of the Marine Biological Association of the United Kingdom, 59, 165-177.

  101. Wisshak, M., Freiwald, A., Lundälv, T. & Gektidis, M., 2005. The physical niche of the bathyal Lophelia pertusa in a non-bathyal setting: environmental controls and palaeoecological implications. Cold-Water Corals and Ecosystems: Springer, pp. 979-1001.

  102. Zibrowius, H., 1980. Les scleractiniaires de la Mediterranee et de l'Atlantique nord oriental. Memoires de l'Institut Oceanograhique, Monaco. 11, 391 pp.

Citation

This review can be cited as:

Perry, F. & Tyler-Walters, H., 2016. Circalittoral Lophelia reefs. In Tyler-Walters H. and Hiscock K. (eds) Marine Life Information Network: Biology and Sensitivity Key Information Reviews, [on-line]. Plymouth: Marine Biological Association of the United Kingdom. Available from: http://www.marlin.ac.uk/habitat/detail/294

Last Updated: 18/03/2016