Chrysophyceae and Haptophyceae on vertical upper littoral fringe soft rock

01-10-2001
Researched byDr Harvey Tyler-Walters Refereed byThis information is not refereed.
EUNIS CodeA1.441 EUNIS NameChrysophyceae and Haptophyceae on vertical upper littoral fringe soft rock

Summary

UK and Ireland classification

EUNIS 2008A1.441Chrysophyceae and Haptophyceae on vertical upper littoral fringe soft rock
EUNIS 2006A1.441Chrysophyceae and Haptophyceae on vertical upper littoral fringe soft rock
JNCC 2004LR.FLR.CvOv.ChrHapChrysophyceae and Haptophyceae on vertical upper littoral fringe soft rock
1997 BiotopeLR.L.ChrChrysophyceae on vertical upper littoral fringe soft rock

Description

Chrysophyceae communities form orange, brownish or blackish gelatinous bands at high tide and supralittoral levels on open cliff faces and in caves and tunnels of soft rock. Open cliff-faces and entrances to chalk caves and tunnels at lower supralittoral levels bear a dark brown band comprising an assemblage dominated by Apistonema carterae. During summer this gelatinous growth dries and often peels off. The filamentous green alga Epicladia perforans is often associated with Apistonema, forming a green layer beneath the upper layer of Apistonema. Entodesmus maritima and Thallochrysis litoralis are commonly associated with Apistonema. Associated with this splash zone algal community is an assemblage of animals of terrestrial origin, with red mites, insects and centipedes commonly found. These species descend into the community as the tide falls and retreat as the tide rises. The most common truly marine species is the small winkle Melarhaphe neritoides. (Information taken from the Marine Biotope Classification for Britain and Ireland, Version 97.06: Connor et al., 1997a, b).

Recorded distribution in Britain and Ireland

Recorded from chalk and other soft rock cliffs on the Calf of Eday, Orkney; St. Andrews Bay, Fife; Flamborough Head; the Thanet and east Kent coasts; the Isle of Wight; Isle of Purbeck, south Dorset coast and Lyme Bay.

Depth range

-

Additional information

This review is primarily based on detailed studies of the supralittoral algal flora by Anand, (1937a,b, &c) and Tittley & Shaw (1980), to which the reader should refer for further information. This review is used to represent the Ulothrix flacca and Urospora sp. biotope LR.UloUro. The Ulva sp. and Blidingia sp. belt is discussed under MLR.Ent and other littoral caves biotopes under LR.Ov.

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Habitat review

Ecology

Ecological and functional relationships

The supralittoral lies above high water springs, and is influenced by wave wash, splash and spray. The mobile fauna will vary with the tide and wave exposure with marine intertidal species further up the shore at high tide and mobile species of terrestrial origin foraging down the shore as the tide recedes only to return to the top of the shore as the tide returns. Other species of terrestrial origin, notably mites (acarids), and some spring tails (Collumbola) seek refuge is cracks and crevices at high tide.
  • Chrysophyceae, Haptophyceae, blue-green algae (Cyanobacteria) and fine filamentous green algae (Chlorophycota) are primary producers, converting sunlight and simple inorganics to biomass.
  • Grazers and browsers feed on unicellular green algae (Chrysophyceae), lichens, and fine filamentous green algae, e.g. the sea slater Ligia oceanica, the bristletail Petrobius maritimus, the small periwinkle Melarhaphne neritoides and some acarid mites (Nicholls, 1931; Joosse, 1976; Roth & Brown, 1976; Pugh & King, 1988; Carefoot & Taylor, 1995; Bücking, 1998).
  • Detritus may accumulate in pits or crevices and is fed on by detritivores such as acarid mites.
  • Predators include mites (acarids), centipedes of terrestrial or intertidal origin (e.g. Strigamia maritima, which may take isopods, amphipods and periwinkles), and terrestrial or maritime spiders (Roth & Brown, 1976; Pugh & King, 1988).
  • The sea slater (Ligia oceanica) may also act as a scavenger (Nicholls, 1931).
Several species are probably more active at night (e.g. Ligia oceanica) to avoid predation by foraging birds. Anand (1937a,b&c) originally described the 'Chrysophyceae' communities of soft chalk cliffs but several species (e.g. Apistonema sp. and Chrysotila sp.) are now described under Haptophyceae (Fowler & Tittley, 1993; van den Hoek et al., 1995), however, the term 'Chrysophyceae' mat or belt is still used.

Seasonal and longer term change

Tittley & Shaw (1980) suggested that Apistonema sp. changed little with season. In winter, the mucilaginous 'Chrysophyceae' mat may be punctuated by light brown or white patches caused by frost. Chrysotila stipitata (Haptophyceae) community develops in winter but in summer may dry and peel off, being restricted to shaded, moist locations. The primary 'Chrysophyceae' community, dominated by Apistonema carterae is best developed in winter but present all year round but in prolonged exposure to sunlight and high temperatures in summer when the seas are calm (low humidity) may result in drying of the mat, which cracks and curls up (Anand, 1937b; Plate IV B). In winter, the mucilaginous mat may be covered by the filamentous growth of Ulothrix sp., and in spring and summer the mat may support numerous species of diatom. Cyanobacteria (e.g. Calothrix sp. and Schizothrix fritschii) are more common in summer. The Rivularia atra belt (see habitat complexity) is best developed in winter but dies back in summer. The growth of the fine green filamentous algae Pseudendoclonium submarinum (previously described by Anand as Endoderma perforans) is favoured in winter (Anand, 1937b; Tittley & Shaw, 1980; Burrows, 1991). No information concerning seasonal changes in the associated fauna was found.

Habitat structure and complexity

This biotope occurs in the supralittoral of soft vertical rock cliffs, above the high water of springs tides, and replaces the Verrucaria maura communities typically found on hard rock substrata. Supralittoral algal communities show a distinct zonation pattern (Anand 1937a,b,&c; Magne, 1974; Tittley & Shaw, 1980). The height of the supralittoral zone and, hence, the height of each individual algal band (or zone) is dependant on moisture and humidity. Moisture or humidity are dependent on the height reached by wave wash, splash and spray and, therefore, on the degree of hence wave exposure, the porosity of the rock, and the drying forces of wind and sunlight and hence, the north or south aspect of the cliff face. For example, on wave exposed North Atlantic headlands the supralittoral may reach 50-60 ft (ca 15-18m) above mean high water springs tides (MHWS) but only reach 4-5 ft (ca 1-1.5m) above on sheltered shores (Lewis, 1964).
The surface of the soft rock provides complexity to the habitat in the form of pits or crevices that retain moisture and may be punctuated by tunnels and caves. Chrysophyceae and Haptophyceae are single celled (unicellular) microalgae more usually found in planktonic communities. The Chrysophyceae and Haptophyceae found in soft rock communities form a thallus of algal cells bound by mucilage or filaments of mucilage (Anand, 1937a; van den Hoek et al., 1995). Anand (1937a,b&c) described five main communities of Chrysophyceae, Haptophyceae and Cyanobacteria associated with the 'Chrysophyceae' mat.

Zonation (down the shore from the yellow and grey lichen belt)
  • An upper belt (45cm or more high) of the fine green filamentous algae Pseudendoclonium submarinum (previously described by Anand as Endoderma perforans), filaments of which penetrate the loose rock and give the rock face a green hue. The Pseudendoclonium submarinum belt may reach 8-10m above high water, more in caves and recesses where the waves break and spray reaches higher.
  • A lower belt of 'Chrysophyceae' communities, forming an orange, light or dark brownish mucilaginous mat. The mucilaginous mat grows over a layer of Pseudendoclonium submarinum that grows endophytically within the 'Chrysophyceae' mat, from which it may protrude. Alternating layers of green algae within the brown Chrysophyceae may form, depending on season.
  • The 'Chrysophyceae' belt is dominated by Apistonema carterae, commonly with Thallochrysis litoralis and Gloeochrysis maritima. Chrysotila stipitata (Haptophyceae) may form a separate 'Chrysophyceae' community, especially in the winter months.
  • Several species of blue-green algae (Cyanobacteria) live endophytically within the 'Chrysophyceae' mat forming layers of black or dark brown growth within the mucilaginous mat, e.g. the Calothrix sp. community. Schizothrix fritschii (Cyanobacteria), however, may form erect branched bundles of a yellowish or green olive colour on the surface of the mat.
  • A band of Rivularia atra (Cyanobacteria) may occur between the bottom of the 'Chrysophyceae' belt and the top of the Ulva sp. zone (Anand, 1937a,b&c; Tittley & Shaw, 1980; Burrows, 1991).
  • In the winter months the mucilaginous mat may be covered by the fine, felt like growth of the green algae Ulothrix sp.
  • The lower limit of this biotope is delimited by a band dominated by Ulva sp. (see MLR.Eph).
Caves
The 'Chrysophyceae' belt is found near the entrance but its vertical extent is increased and it may extend for 6 -8m from the floor in well illuminated caves The dominant species vary with light intensity and hence, distance into the cave (Anand, 1937b). Pseudendoclonium submarinum (described as Endoderma perforans) penetrates the surface of the mucilaginous mat giving it a green colour. Pseudendoclonium submarinum becomes more prominent in vertical extent in caves than on open cliffs. Anand (1937b) describes three algal communities specific to soft rock caves.

Productivity

The Chrysophyceae, Haptophyceae, the associated Chlorophycota and Cyanobacteria provide primary production within this biotope. However, no further information was found.

Recruitment processes

Chrysophyceae and Haptophyceae reproduce predominantly by asexual reproduction. Flagellate zoospores may also be produced. The Haptophyta Chrysotlia lamellosa is predominately benthic but the motile flagellate part of the life-cycle is an abundant member of the phytoplankton, previously described as Isochrysis maritima. The fine, filamentous green algae found in this biotope produce motile zoospores and swarmers. While Cyanobacteria do not form flagellate cells, they are ubiquitous. Hence, the algae species within this biotope have a high potential for dispersal, depending on local currents.

Therefore, it is likely that recolonization of soft rock cliffs would be relatively rapid, probably occurring within a year. Tittley & Shaw (1980) noted that Apistonema sp. was replaced by Entophysalis sp. (Cyanobacteria) on sea walls and that hard, impervious rock substrata supported different algae communities to those of soft, porous rock substrata. This was probably dependent o the moisture retained by the porous rock surface, e.g. chalk and the ability of algal spores to settle and stick to rough rather than smooth surfaces (Tittley & Shaw, 1980).

Time for community to reach maturity

Little information was found. The 'Chrysophyceae' communities develop in winter, with Cyanobacteria developing in spring and summer, suggesting a seasonal cycle. Therefore, it is likely that the community would reach maturity within a year.

Additional information

With the exception of the studies indicated above, the ecology of soft rock algal communities has received little attention.

Preferences & Distribution

Recorded distribution in Britain and IrelandRecorded from chalk and other soft rock cliffs on the Calf of Eday, Orkney; St. Andrews Bay, Fife; Flamborough Head; the Thanet and east Kent coasts; the Isle of Wight; Isle of Purbeck, south Dorset coast and Lyme Bay.

Habitat preferences

Depth Range
Water clarity preferences
Limiting Nutrients Phosphorus (phosphates), Silicon (silicates), Nitrogen (nitrates)
Salinity Full (30-40 psu), Variable (18-40 psu)
Physiographic
Biological Zone Upper infralittoral
Substratum
Tidal Moderately Strong 1 to 3 knots (0.5-1.5 m/sec.), Weak < 1 knot (<0.5 m/sec.)
Wave Moderately exposed
Other preferences Soft porous rock

Additional Information

Soft rocks such as sandstone, limestone (or brick) but especially chalk support diverse algal communities characteristic of this biotope. However, on smooth, impermeable rock surfaces (including artificial substrata such as concrete) the Chrysophyceae and Haptophyceae were replaced by Cyanobacteria (Entophysalis sp.) (Tittley & Shaw, 1980; Fowler & Tittley, 1993).

Several members of this community, especially the fine filamentous algae, Chrysophyceae and Haptophyceae are difficult to identify. Therefore, this biotope and its component species may be under recorded in the British Isles. However, the distribution of this biotope is limited to suitable environmental conditions on suitable rock surfaces (e.g. chalk cliffs) many of which have been affected by the construction of sea defences resulting in loss of this biotope in parts of the UK (see importance; Fowler & Tittley, 1993).

Species composition

Species found especially in this biotope

  • Apistonema carterae
  • Chrysotila lamellosa
  • Chrysotila stipitata
  • Ectocarpus sp.
  • Entocladia viridis
  • Entodesmis litoralis
  • Entodesmis maritima
  • Gleochrysis maritima
  • Kuetzingiella holmesii
  • Petalonia filiformis
  • Pleurocladia lacustris
  • Praisnocladus lubricus
  • Pringsheimiella scutata
  • Pseudendoclonium submarinum
  • Thallochrysis litoralis
  • Trebouxia humicola
  • Ulvella lens

Rare or scarce species associated with this biotope

-

Additional information

The composition of the 'Chrysophyceae' communities and associated species were described in detail by Anand (1937a,b,&c) and in subsequent surveys by Tittley & Shaw (1980) and Tittley (1985; 1988). Anand (1937b) described two main Chrysophyceae communities and three associated Cyanobacteria communities in addition to the Pseudendoclonium submarinum community. In addition, Anand (1937a) recorded two species new to the British Isles and several rare species (see Fowler & Tittley, 1993).

Sensitivity reviewHow is sensitivity assessed?

Explanation

This biotope is characterized by the presence of the mucilaginous mat of Chrysophyceae and Haptophyceae, dominated by Apistonema carterae, growing in association with Pseudendoclonium submarinum (previously described by Anand as Endoderma perforans). The composition of the 'Chrysophyceae' communities varies with season, moisture and in caves or tunnels. The arthropod community (red mites, insects, centipedes and spiders) are mobile species that are found within the supralittoral and are not dependant on this biotope. Therefore, the 'Chrysophyceae' communities as a whole have been used to indicate the sensitivity of the biotope and no indicative species were chosen. However, in undertaking this assessment of sensitivity, account was taken of knowledge of the biology of all characterizing species in the biotope.

Species indicative of sensitivity

Community ImportanceSpecies nameCommon Name

Physical Pressures

 IntoleranceRecoverabilitySensitivitySpecies RichnessEvidence/Confidence
High High Moderate Major decline High
Removal of the substratum will result in the removal and loss of the biotope. Therefore, an intolerance of high has been recorded. Rock falls may be a natural dynamic feature of this biotope resulting in loss of areas of substratum and its associated biotopes but revealing new substratum for colonization. However, where the substratum is modified, e.g. by coastal defence structures, recovery may not be possible (see importance). The microalgae within this biotope can probably colonize new substratum and grow rapidly, probably within a year (see additional information below). Therefore a recoverability of high has been recorded.
Not relevant Not relevant Not relevant Not relevant Not relevant
Smothering could occur as a result of rainwater runoff of silt and soil from the tops of the cliffs. However, the slope of the cliff would preclude the build up of significant deposits (except on crevices and pits) sufficient to block the algal communities access to sunlight. Therefore, the factor is probably not relevant at the level of the benchmark. Smothering by impermeable materials or by other hard construction materials, however, would result in loss of the biotope.
Not relevant Not relevant Not relevant Not relevant Not relevant
This biotope is unlikely to be affected by changes in suspended sediment since it is only exposed to wave splash or spray. Therefore, this factor is probably not relevant. However, it may be covered in silt due to heavy rainfall (see smothering above).
Not sensitive* No change Low
This biotope is unlikely to be affected by changes in suspended sediment since it is only exposed to wave splash or spray. Therefore, this factor is probably not relevant. However, it may be covered in silt due to heavy rainfall (see smothering above).
High High Moderate Major decline High
Risk of desiccation, high salt concentration due to evaporation and temperature change increase with increasing height above high tide. Anand (1937c) carried out a detailed, quantified study of the amount of spray, rates of drying, evaporation rates, capillarity and salinity changes in chalk cliff algal communities. Anand (1937c) made the following important observations:
  • the 'Chrysophyceae' belt received little spray, and in summer may suffer up to three days of drought, separated by only brief exposure to spray during calm weather;
  • the Pseudendoclonium submarinum belt was rarely wetted except in stormy weather, and was exposed to long periods of drought of up to three days;
  • the mucilaginous 'Chrysophyceae' belt retains more water and losses water by evaporation or drainage slower than the Ulva sp. belt beneath it, loosing only 6.8-11.3% of water by evaporation after 5hrs in the field or 15.7% after 12hrs in the laboratory;
  • however, prolonged high temperatures and direct sunlight n summer result in drying and cracking of the 'Chrysophyceae' mat (Anand, 1937b&c).
Anand (1937c) concluded that the 'Chrysophyceae' succeed in an inhospitable habitat, probably due to water retention by the mucilaginous mat, which also reduces their exposure to extremes of salt concentration and temperature. Tittley & Shaw (1980) also reported that chalk absorbed more water and released it more slowly on drying than concrete, suggesting that the water retention by the substratum was important for the development and height of the algal belts.
Overall, the 'Chrysophyceae' belt and Pseudendoclonium submarinum in particular are extremely tolerant of desiccation when compared to other intertidal organisms. However, the 'Chrysophyceae' belt inhabits a narrow habitat where a particular range of environmental conditions occurs (desiccation, sunlight, substratum and temperature) and is, therefore, probably highly intolerant of a change in desiccation at the level of the benchmark, especially during summer. An increase in the length of the time between spray events is likely to reduce the extent or duration of the population and reduce its height on the shore. However, physical removal from the effects of the sea (wave splash and spray) for long periods of time, e.g. by coastal defences, has been shown to result in loss of suitable environmental conditions and loss of the biotope (see importance: Fowler & Tittley, 1993; Anon, 1999e). Therefore, an intolerance of high has been recorded. Once prior conditions return, recovery is likely to be rapid (see additional information below).
Intermediate Very high Low Decline Low
An increase in emergence will result in a reduction in the height reached by wave splash and spray. Hence, the height of the algal communities in the supralittoral will also be reduced, resulting in the biotope effectively moving down the shore. Some species particularly abundant in more moist conditions may be lost. Therefore, the extent or abundance of the biotope is likely to be reduced and an intolerance of intermediate has been recorded at the benchmark level. However, physical removal from the effects of the sea (wave splay and spray) for long periods of time, e.g. by coastal defences has been shown to result in loss of suitable environmental conditions and loss of the biotope (see importance; Fowler & Tittley, 1993; Anon, 1999e). Once prior conditions return, recovery is likely to be rapid (see additional information below).
Low Immediate Not relevant Minor decline Low
A decrease in emergence equivalent to a 1 hour change cover by the sea (see benchmark) would expose the habitat to an increased level of spray. However, decreased emergence will allow the algal communities to colonize further up the shore, so that the entire zonation (see habitat complexity) will probably move up the shore. Therefore, an intolerance of low has been recorded.
Not relevant Not relevant Not relevant Not relevant Not relevant
This biotope is never directly covered by the sea and is, therefore, not affected by water flow rates.
Intermediate Very high Low Decline High
This biotope is never directly covered by the sea and is, therefore, not affected by water flow rates.
Intermediate Very high Low Minor decline Low
Anand (1937c) examined the range of temperatures experienced by chalk cliff algal communities. The Pseudendoclonium submarinum belt was exposed to temperatures slightly less than air (since the cliff face heats up slowly) but similar variability in temperature to that of the air. The mucilaginous Chrysophyceae belt was consistently lower in temperature than the air and was least affected by changes in air temperature and showed no marked variation over several hours. Anand (1937c) concluded that its water content and retention acted as a buffer against temperature change. Curiously, in contrast, the Ulva sp. and Fucus sp. belts of the lower shore showed a much greater range of temperatures, especially in bright sunlight. However, Anand (1937b&c) also noted that prolonged exposure to high temperatures during summer in desiccating conditions resulted in death, cracking and peeling off of the 'Chrysophyceae' belt. The mat was seldom seen to crack in areas sheltered from direct sunlight and/or wind.
Overall, therefore an increase in annual temperatures (at the benchmark level) is likely to increase the risk of desiccation and exposure to high temperatures during summer, resulting in loss of the proportion of the population depending on its shelter and aspect. Hence, an intolerance of intermediate has been recorded. Once prior conditions return, recovery is likely to be rapid (see additional information below).
Tolerant* Not sensitive Rise Very low
Anand (1937b&c) reported that light brown or white patches appeared in the 'Chrysophyceae' mat during winter due to frost. However, little other information concerning low temperatures was found. A decrease in annual winter temperatures is likely to increase the risk of frost, however, a reduction in average summer temperatures, will reduce the risk of desiccation. Since the Chrysophyceae communities are best developed in winter and the associated Cyanobacteria communities develop in spring and summer the biotope as a whole may benefit from a reduction in average summer temperatures. Therefore, not sensitive* has been recorded.
Not relevant Not relevant Not relevant Not relevant Not relevant
This biotope is never directly covered by the sea and is, therefore, not affected by changes in turbidity.
Not sensitive* Not relevant
This biotope is never directly covered by the sea and is, therefore, not affected by changes in turbidity.
Tolerant* Not relevant Not sensitive* Rise High
The height and extent of the supralittoral, and hence the communities it supports is dependant on wave wash, splash and spray, and therefore, wave exposure. Anand (1937b&c) noted that the Pseudendoclonium submarinum belt could reach up to 8-10m above high water but in caves or recesses where waves break and create more spray the algal communities could extend higher up the shore. Similarly, Lewis (1964) noted that the supralittoral could reach 50-60 ft above mean high water springs on wave exposed North Atlantic headlands. increased wave exposure is likely to increase the overall height of the supralittoral and increase the height and extent of the associated algal communities. Therefore, not sensitive* has been recorded. Increased spray may also allow a more diverse community to develop resulting in a rise in species richness.
Intermediate Very high Low Decline High
The height and extent of the supralittoral, and hence the communities it supports is dependant on wave wash, splash and spray, and therefore, wave exposure. A decrease in wave exposure is likely to reduce the height of the supralittoral and hence the extent of its associated algal communities. Therefore, an intolerance of intermediate has been recorded. Once prior conditions return, recovery is likely to be rapid (see additional information below).
Tolerant Not relevant Not relevant No change High
Microalgae have no known sound receptors and are unlikely to respond to vibration.
Tolerant Not relevant Not relevant No change High
Microalgae can orientate themselves to light when motile. However, visual acuity is probably non-existent and they are unlikely to respond to visual presence or periodic shading, especially when fixed to the substratum in the form of a thallus.
Intermediate Very high Low Major decline Moderate
The 'Chrysophyceae' mat is very thin (a few millimetres) and the Pseudendoclonium submarinum belt exists as a thin coasting of the rock. These algal communities are likely to be removed as a result of any abrasion, e.g. from stranding or trampling, especially where the friable rock surface is removed. Therefore, an intolerance of intermediate has been recorded. However, recovery is likely to be rapid if suitable substratum remains (see additional information below).
High High Moderate Major decline Very low
Rock falls are probably a natural feature of soft rock communities. Any algal communities present on falling rocks will be deposited at the base of the cliff in the intertidal and will be lost. No information concerning displacement or transplantation was found, however, it is probable that any part of the 'Chrysophyceae' or Pseudendoclonium submarinum communities removed from the substratum is unlikely to be able to reattach to suitable substratum and will be lost. Therefore, an intolerance of high has been recorded. However, recovery is likely to be rapid if suitable substratum remains (see additional information below).

Chemical Pressures

 IntoleranceRecoverabilitySensitivityRichnessEvidence/Confidence
Intermediate Very high Low Decline Moderate
No information of the effects of synthetic chemicals on soft rock algal communities was found. However, 1µg/l TBT was shown to significantly reduce growth of the diatoms Pavlova lutheri and Dunaliella tertiolecta and Skeletonema costatum would not grow at 100 ng/l TBT. All species died at 5 µg/l TBT (Beaumont & Newman, 1986; Bryan & Gibbs, 1991). Bryan & Gibbs (19910 reported that TBT suppressed growth of the Skeletonema costatum (EC50 350ng/l) and Thalassiosira pseudonana (EC50 1.15 µg/l). Cole et al. (1999) reported that TBT impaired the development of motile spores of green macroalgae (5 day EC50 of 1 ng/l TBT), which were considered the most intolerant phase of their life cycle. In addition, Cole et al. (1999) suggested that the herbicides Atrazine, Simazine, Diuron, Linuron and the insecticide Dimethoate were probably very toxic to algae.
Therefore, it is probable that soft rock algal communities are intolerant of synthetic chemicals, in particular herbicides that may be contained in runoff (during heavy rains) from adjacent agricultural land. Hence an intolerance of intermediate has been recorded. However, recovery is likely to be rapid if suitable substratum remains (see additional information below).
Heavy metal contamination
Intermediate Very high Low Decline Low
Cole et al. (1999) suggest that Pb, Zn, Ni and As were probably very toxic to algae. Therefore, in the absence of any specific studies an intolerance of intermediate has been recorded. However, recovery is likely to be rapid if suitable substratum remains (see additional information below).
Hydrocarbon contamination
No information Not relevant No information Insufficient
information
Not relevant
No information concerning the effects of hydrocarbons or oil spills on supralittoral algal communities was found.
Radionuclide contamination
No information Not relevant No information Insufficient
information
Not relevant
Insufficient
information
Changes in nutrient levels
No information Not relevant No information Insufficient
information
Not relevant
Maritime cliff plant and algae communities are probably nutrient poor, i.e. lack nutrients. A increase in nutrients in the form of runoff from adjacent agricultural land may benefit the communities. However, the opportunistic filamentous algae such as Ulothrix sp. and Urospora sp. and even Pseudendoclonium submarinum may overgrow the 'Chrysophyceae' belt, resulting in the dominance of a few species at the expense of a more diverse community. However, no information concerning the effects of nutrient enrichment on these communities was found and no intolerance assessment was recorded.
Tolerant Not relevant Not relevant No change Low
Although not covered by seawater, the supralittoral experiences a wide range of salinities due to the evaporation of wave splash and spray, resulting in high salt concentrations, and exposure to rain and freshwater runoff. Anand (1937c) showed that the salt concentration in the 'Chrysophyceae' belt was higher than in the Ulva sp. Belt (lower on the shore) but (due to water retention) did not experience as great an increase in salt concentration once the tide fell. However, in the 'Chrysophyceae' belt the salt concentration may be approximately 3 times that of seawater (Anand, 1937c). Therefore, since soft rock algal communities are also likely to be exposed to fresh water in the form of rain, this biotope is probably not intolerant of changes in salinity comparable to the benchmark.
Tolerant Not sensitive* No change Low
See above.
Not relevant Not relevant Not relevant Not relevant Not relevant
This biotope is exposed to the air and therefore unlikely to experience hypoxia or anoxia.

Biological Pressures

 IntoleranceRecoverabilitySensitivityRichnessEvidence/Confidence
No information Not relevant No information Insufficient
information
Not relevant
No information found
No information Not relevant No information Insufficient
information
Not relevant
No information found
Not relevant Not relevant Not relevant Not relevant Not relevant
Soft rock algal communities are unlikely to be subject to extraction.
Not relevant Not relevant Not relevant Not relevant Not relevant

Additional information

Recoverability

Recovery will depend on regrowth from existing thallus or filaments and should be rapid. The 'Chrysophyceae' communities develop over winter, and several members of soft rock algal communities develop rapidly in spring.
Most members of these algal communities produce motile spores or have a motile pelagic stage in their life cycle (except Cyanobacteria) and have the potential to disperse widely with effectively high fecundity. Therefore, once suitable habitat or environmental conditions return recovery is likely to be rapid, probably taking a year at most. However, little direct evidence of recovery rates was found.

Importance review

Policy/Legislation

Habitats of Principal ImportanceIntertidal chalk [N. Ireland, England]
Habitats of Conservation ImportanceLittoral chalk communities
Habitats Directive Annex 1Reefs, Submerged or partially submerged sea caves
UK Biodiversity Action Plan PriorityIntertidal chalk
OSPAR Annex VLittoral chalk communities

Exploitation

The algal communities characteristic of this biotope are not subject to exploitation. However, chalk cliff algal communities and this biotope are considered rare in the UK. Their rarity may be attributable to the scarcity of their habitat (see ecology and sensitivity) as a result of coastal defence works.

Urban and industrial development in the south east UK, resulted in a need for coastal defence works to stabilise cliffs and reduce coastal erosion. The construction of sea walls at the base of cliffs cuts off caves and tunnels from the inundation by the sea and prevents sea wash or spray reaching the cliff face. The cliff face may also be scarped and straightened to reduce falls and gullies torn down, resulting in loss of substratum (Fowler & Tittley, 1993). The resultant sea walls do not support the 'Chrysophyceae' algal communities, although limestone and brick structures support similar communities but with a reduced range of chalk species and communities (Tittley & Shaw, 1980; Fowler & Tittley, 1993). Tittley et al. (1998) surveyed chalk cliffs throughout England and revealed that 56% of coastal chalk in Kent and 33% in Sussex had been modified by coastal defence and other works. On the Isle of Thanet this increased to 74% and had resulted in the loss of a wide range of micro-habitats on the upper shore and the removal of splash-zone communities. Elsewhere in England, coastal chalk remains in a largely natural state (Anon, 1999e, Tittley et al., 1998).

Fowler & Tittley (1993) noted that the brown algae Kuetzingiella holmesii, characteristic of cave communities and Pleurocladia lacustris had not been re-recorded since the 1930s.
Chalk cliff communities are included in the Flamborough Head, Thanet Coast, South Wight and Rathlin Island, and South Wight Maritime candidate SACs (Anon, 1999e).

Additional information

-

Bibliography

  1. Anand, P.L., 1937a. A taxonomic study of the algae of British Chalk-cliffs. Journal of Botany, 75 (Supplement II), 1-51.
  2. Anand, P.L., 1937b. An ecological study of the algae of the British chalk cliffs. Part I. Journal of Ecology, 25, 153-188.
  3. Anand, P.L., 1937c. An ecological study of the algae of the British chalk cliffs. Part II. Journal of Ecology, 25, 344-367.
  4. Anonymous, 1999e. Littoral and sublittoral chalk. http://www.ukbap.org.uk/ukplans.aspx?id=31, 2001-09-26
  5. Beaumont, A.R. & Newman, P.B., 1986. Low levels of tributyl tin reduce growth of marine micro-algae. Marine Pollution Bulletin, 17, 457-461.
  6. 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.
  7. B├╝cking, J., 1998. Investigations on the feeding habits of the rocky shore mite Hyadesia fusca (Acari: Astigmata: Hyadesiidae): diet range, food preference, food quality, and the implications for distribution patterns. Helgolander Meersuntersuchungen, 52, 159-177.
  8. Burrows, E.M., 1991. Seaweeds of the British Isles. Volume 2. Chlorophyta. London: British Museum (Natural History).
  9. Carefoot, T.H. & Taylor, B.E., 1995. Ligia: a prototypal terrestrial isopod. In Terrestrial isopod biology (ed. M.A. Alikhan), pp. 47-60. Rotterdam: A.A. Balkema. [Crustacean Issues 9.]
  10. Cheng, L. (ed.), 1976. Marine insects. Amsterdam: North-Holland Publishing Company.
  11. Cole, S., Codling, I.D., Parr, W. & Zabel, T., 1999. Guidelines for managing water quality impacts within UK European Marine sites. Natura 2000 report prepared for the UK Marine SACs Project. 441 pp., Swindon: Water Research Council on behalf of EN, SNH, CCW, JNCC, SAMS and EHS. [UK Marine SACs Project.], http://www.ukmarinesac.org.uk/
  12. Connor, D.W., Brazier, D.P., Hill, T.O., & Northen, K.O., 1997b. Marine biotope classification for Britain and Ireland. Vol. 1. Littoral biotopes. Joint Nature Conservation Committee, Peterborough, JNCC Report no. 229, Version 97.06., Joint Nature Conservation Committee, Peterborough, JNCC Report No. 230, Version 97.06.
  13. Davies, C.E. & Moss, D., 1998. European Union Nature Information System (EUNIS) Habitat Classification. Report to European Topic Centre on Nature Conservation from the Institute of Terrestrial Ecology, Monks Wood, Cambridgeshire. [Final draft with further revisions to marine habitats.], Brussels: European Environment Agency.
  14. Fletcher, R.L., 1987. Seaweeds of the British Isles vol. 3. Fucophyceae (Phaeophyceae) Part 1. London: British Museum (Natural History).
  15. Fowler, S.L. & Tittley, I., 1993. The marine nature conservation importance of British coastal chalk cliff habitats. English Nature Research Reports, no. 32.
  16. JNCC (Joint Nature Conservation Committee), 1999. Marine Environment Resource Mapping And Information Database (MERMAID): Marine Nature Conservation Review Survey Database. [on-line] http://www.jncc.gov.uk/mermaid,
  17. Joosse, E.N.G., 1976. Littoral apterygotes (Collembola and Thysanura). In Marine insects (ed. L. Cheng), pp. 151-186. Amsterdam: North-Holland Publishing Company.
  18. Lewis, J.R., 1964. The Ecology of Rocky Shores. London: English Universities Press.
  19. Magne, F., 1974. Peuplement d'un substrat calcaire dans la zone intercotidale. Bulletin. Société phycologique de France. Paris, 19, 121-128.
  20. Nicholls, A.G., 1931. Studies on Ligia oceanica. Part II. The process of feeding, digestion and absorption, with a description of the structure of the foregut. Journal of the Marine Biological Association of the United Kingdom, 17, 675-705.
  21. Pugh, P.J.A. & King, P.E., 1988. Acari of the British Isles. Journal of Natural History, 22, 107-122.
  22. Roth, V.D. & Brown, W.L., 1976. Other intertidal air-breathing arthropods. In Marine insects (ed. L. Cheng), pp. 119-150.
  23. Tittley, I. & Shaw, K.M., 1980. Numerical and field methods in the study of the marine flora of chalk cliffs. In The shore environment, vol. 1: methods (ed. J.H. Price, D.E.G. Irvine & W.F. Farnham), pp. 213-240. London & New York: Academic Press. [Systematics Association Special Volume, no. 17(a).]
  24. Tittley, I., 1985. Chalk cliff algal communities of Kent and Sussex, Southeast England. Nature Conservancy Council, Contract Reports, no. 200., Peterborough: Nature Conservancy Council.
  25. Tittley, I., 1988. Chalk cliff algal communities: 2. Outside south eastern England. Nature Conservancy Council, Contract Reports, no. 878., London: British Museum (Natural History).
  26. Tittley, I., Spurrier, C.J.H., Chimonides, P.J., George, J.D., Moore, J.A., Evans, N.J. & Muir, A.I., 1998. Survey of chalk cave, cliff, intertidal and subtidal reef biotopes in the Thanet coast cSAC. Report to English Nature., London: Natural History Museum.
  27. Van den Hoek, C., Mann, D.G. & Jahns, H.M., 1995. Algae: an introduction to phycology: Cambridge University Press.

Citation

This review can be cited as:

Tyler-Walters, H., 2001. Chrysophyceae and Haptophyceae on vertical upper littoral fringe soft rock. 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/121

Last Updated: 01/10/2001

Tags: green algae blue green algae soft rock chalk splash zone vertical cliff supralittoral