|Researched by||Dr Keith Hiscock||Refereed by||This information is not refereed.|
- none -
|Water clarity preferences|
|Limiting Nutrients||No information found|
This MarLIN sensitivity assessment has been superseded by the MarESA approach to sensitivity assessment. MarLIN assessments used an approach that has now been modified to reflect the most recent conservation imperatives and terminology and are due to be updated by 2016/17.
|Community Importance||Species name||Common Name|
|Important other||Botryllus schlosseri||Star sea squirt|
|Important characterizing||Delesseria sanguinea||Sea beech|
|Important functional||Halichondria panicea||Breadcrumb sponge|
|Key structural||Saccharina latissima||Sugar kelp|
|Most of the species characteristic of this biotope are permanently attached to the substratum so would be removed upon substratum loss. For recoverability, see Additional Information.|
|Some species, especially Saccharina latissima, are likely to protrude above smothering material. Others such as the active suspension feeders and foliose algae are likely to be killed by smothering. For recoverability, see Additional Information.|
|Low||Very high||Very Low||No change||Moderate|
|Increased suspended sediment levels will reduce the amount of light reaching the seabed and may therefore inhibit photosynthesis of the algal component of the biotope. However, the biotope occurs in very shallow depths and algae are likely to survive. Increased suspended sediment is unlikely to have a significant effect in terms of smothering by settlement in the regime of strong water flow typical of this biotope. However, silt may clog respiratory and feeding organs (especially sea squirts). Since many of the species in this biotope live in areas of high silt content (turbid water) it is expected that they would survive increased levels of silt in the water. Both algae and animals would suffer some decrease in viability. On return to lower suspended sediment levels it is expected that recovery of condition will be rapid.|
|Decreased suspended sediment levels will increase the amount of light reaching the seabed and may therefore increase competitiveness of the algal component of the biotope. Suspended sediment may include organic matter and a decrease may reduce the amount of food available to suspension feeding animals. Both algae and animals would suffer some decrease in viability. On return to higher suspended sediment levels it is expected that recovery of condition will be rapid.|
|The biotope is predominantly sublittoral but does extend onto the shore and therefore has some ability to resist desiccation. On a sunny day at low water of spring tides, damage (bleaching) is likely to occur to the Saccharina latissima plants but not destroy them completely. Species living below the kelp fronds will be protected by them from the worst effects of desiccation. Sponges, such as Halichondria panicea, are likely to withstand some desiccation as they hold water.|
|The biotope is predominantly sublittoral and the dominant species (Saccharina latissima) and many of the subordinate species, especially solitary sea squirts, are unlikely to survive an increased emergence regime. Several mobile species are likely to move away. However, providing that suitable substrata are present, the biotope is likely to re-establish further down the shore within a similar emergence regime to that which existed previously. For recoverability, see additional information below.|
|Tolerant*||Not sensitive||No change||High|
|The biotope is subtidal and thrives in fully submerged conditions.|
|Increase in tidal flow rates may dislodge substrata (especially where large plants of Saccharina latissima subject to drag are attached to cobbles). Also, increased water flow rate may result in certain species being unable to feed when water flow is likely to damage feeding organs (see Hiscock 1983). However, it is unlikely that species attached to non-mobile substrata in the biotope will be killed by an increase in flow rate. Therefore a decline in the abundance of some species that are swept away is suggested with some reduction in viability of others depending on whether the current velocity reaches a high enough level to inhibit feeding.|
|Not sensitive*||Not relevant|
|Decreased water flow will lead to a reduced competitive advantage for suspension feeding animals especially sponges which will decline in growth rate so that seaweeds will tend to become more dominant. Reduction in water flow rate will also allow settlement of silt with associated smothering. It is therefore expected that, although there might be only a minor decline in species, the biotope will change, possibly to SIR.Lsac.Cod (Sparse Laminaria saccharina with Codium spp. and sparse red seaweeds on heavily silted very sheltered infralittoral rock). Because the biotope is likely to change, an intolerance of high is given. For recoverability, see Additional Information.|
|Low||Very high||Very Low||No change||Low|
|The biotope occurs in warmer and colder parts of Britain and Ireland and similar assemblages of species are known to occur in Scandinavia and in Brittany so that long-term temperature change is unlikely to cause a significant impact. However, exposure to high temperatures for several days may produce stress in some component species but recovery would be expected to be rapid.|
|Low||Very high||Moderate||No change||Low|
|The biotope occurs in warmer and colder parts of Britain and Ireland and similar assemblages of species are known to occur in Scandinavia and in Brittany so that long-term temperature change is unlikely to cause a significant impact. There is a single record of Halichondria panicea being adversely affected by frost during the 1963/64 winter (Crisp, 1964).|
|Several of the characteristic species are algae that rely on light for photosynthesis. Reduction in light penetration as a result of higher turbidity is unlikely to be fatal to algae in the short term but in the long term will result in a reduction in downward extent and therefore overall extent of the biotope. Species richness may decline in the long-term as algae are unable to survive high turbidity and low light but reduced extent of the biotope (depth limits) is the most significant likely decline.|
|Tolerant*||Not sensitive||No change||Low|
|Decreased turbidity and the subsequent increase in light levels is likely to result in an extension of the downward extent of the biotope. Not sensitive* is therefore indicated.|
|This is a fundamentally sheltered coast biotope with species that do not appear to occur in wave exposed situations. Increased wave action is likely to dislodge Saccharina latissima plants and interfere with feeding in solitary tunicates. Massive growths of Halichondria panicea are likely to be displaced. Although 'major decline' is indicated with regard to species richness, the results of increased wave exposure would be replacement of biotope-characteristic species with others and the development of a different biotope. A change of biotope means high intolerance. On return to previous conditions, the 'new' biotope would have to degrade before SIR.Lsac.T developed. Nevertheless, such a change should occur within five years and a recoverability of high is indicated (see additional information below). For recoverability, see Additional Information.|
|Not sensitive*||Not relevant|
|This biotope occurs in locations not subject to any significant wave exposure so that decrease in wave exposure is considered not relevant.|
|Tolerant||Not relevant||Not relevant||No change||High|
|The macroalgae characterizing the biotope have no known sound or vibration sensors. The response of macroinvertebrates is not known.|
|Tolerant||Not relevant||Not relevant||No change||High|
|Macrophytes have no known visual sensors. Most macroinvertebrates have poor or short range perception and are unlikely to be affected by visual disturbance such as shading.|
|Saccharina latissima, other algae, sponges and the large solitary tunicates are likely to be removed from the substratum by physical disturbance. Physical disturbance will also overturn boulders and cobbles so that the epibiota becomes buried. Mortality of species is therefore likely to be high although many, particularly mobile species, will survive. For recoverability, see additional information.|
|Although many of the species in the biotope are sessile and would therefore be killed if removed from their substratum, displacement will often be of the boulders or cobbles on which the community occurs in which case survival will be high. The 'Intermediate' ranking given here supposes that some individual sessile organisms will be removed and die. Mobile organisms such as the prosobranchs in the biotope are likely to survive displacement. Recovery rate assumes that the characteristic species of the biotope will remain, albeit in lower numbers. However, where species have been removed, most have a planktonic larva and/or are mobile and so can migrate into the affected area. For recoverability, see Additional Information.|
|Several of the species characteristic of the biotope are reported as having high intolerance to synthetic chemicals. For instance, Cole et al. (1999) suggested that herbicides such as Simazine and Atrazine were very toxic to macrophytic algae. Hiscock & Hoare (1974) noted that almost all red algal species and many animal species were absent from Amlwch Bay in North Wales adjacent to an acidified halogenated effluent. Red algae have also been found to be sensitive to oil spill dispersants (O'Brien & Dixon 1976; Grundy quoted in Holt et al., 1995). Recovery is likely to occur fairly rapidly. For recoverability, see Additional Information.|
|No information||Not relevant||No information||Insufficient
|Red algae have been found to be sensitive to oil and oil spill dispersants (O'Brien & Dixon, 1976; Grundy quoted in Holt et al., 1995). Foliose red algae in the biotope may therefore be subject to bleaching and death. Holt et al. (1995) reported that Saccharina latissima (studied as Laminaria saccharina) had been observed to show no discernible effects from oil spills. The shallow nature of this biotope suggests that oil might diffuse in significant quantities to the biota. However, the presence of strong tidal flow makes it likely that oil will be flushed away. Overall, an intolerance of intermediate is suggested.|
|No information||Not relevant||No information||Insufficient
|Evidence is equivocal. For Saccharina latissima (studied as Laminaria saccharina), Conolly & Drew (1985) found that plants at the most eutrophic site in a study on the east coast of Scotland where nutrient levels were 25% higher than average exhibited a higher growth rate. However, Read et al. (1983) reported that, after removal of a major sewage pollution in the Firth of Forth, Saccharina latissima (studied as Laminaria saccharina) became abundant where previously it had been absent. Increased nutrients may increase the abundance of ephemeral algae and result in smothering or changing the character of the biotope. Any recovery is likely to be high as species are unlikely to be completely lost and have planktonic larvae and high growth rates. See also Additional Information.|
|Tolerant||Not relevant||Not relevant||No change||Moderate|
|The biotope occurs in full or variable salinity conditions and does not include species that are characteristically found in low salinity and that would be lost by an increase in salinity.|
|The biotope occurs in situations that are naturally subject to fluctuating or low salinities: it grows in areas where freshwater run-off dilutes near-surface waters and most components are likely to survive reduced salinity conditions. For instance, Saccharina latissima (studied as Laminaria saccharina) can survive in salinities of 8 psu although growth is retarded below 16 psu (Kain, 1979). Delesseria sanguinea is also tolerant of salinities as low as 11 psu in the North Sea whilst Halichondria panicea occurs in the reduced salinity of the western Baltic probably as low as 14 psu. Most characteristic species are likely to survive reduced salinity but species that are lost are likely to have planktonic larvae and recolonize rapidly. See also Additional Information.|
|The biotope occurs in areas where still water conditions do not occur and so some species may be intolerant of hypoxia. Cole et al. (1999) suggest possible adverse effects on marine species below 4 mg/l and probable adverse effects below 2mg/l. However, on return to oxygenated conditions, rapid recovery is likely.|
|There is little information on microbial pathogen effects on the characterizing species in this biotope. However, Saccharina latissima may be infected by the microscopic brown alga Streblonema aecidioides. Infected algae show symptoms of Streblonema disease, i.e. alterations of the blade and stipe ranging from dark spots to heavy deformations and completely crippled thalli (Peters & Scaffelke, 1996). Infection can reduce growth rates of host algae. It is likely that microbial pathogens will have only a minor possible impact on this biotope.|
|The non-native species currently (October 2000) most likely to colonize this biotope is Sargassum muticum which is generally considered to be a 'gap-filler'. However, it may displace some native species. Potential non-native colonists are the kelp Undaria pinnatifida which may significantly displace Saccharina latissima but not change other components.|
|Extraction of Saccharina latissima may occur but the plant rapidly colonizes cleared areas of the substratum: Kain (1975) recorded that Saccharina latissima (studied as Laminaria saccharina) was abundant six months after the substratum was cleared so recovery should be rapid. Associated species are unlikely to be affected by removal of Saccharina latissima unless protection from desiccation on the lower shore is important.|
Barthel, D., 1988. On the ecophysiology of the sponge Halichondria panicea in Kiel Bight. II. Biomass, production, energy budget and integration in environmental processes. Marine Ecology Progress Series, 43, 87-93.
Conolly N.J. & Drew, E.A., 1985. Physiology of Laminaria. III. Effect of a coastal eutrophication on seasonal patterns of growth and tissue composition in Laminaria digitata and L. saccharina. Marine Ecology, Pubblicazioni della Stazione Zoologica di Napoli I, 6, 181-195.
Crisp, D.J. (ed.), 1964. The effects of the severe winter of 1962-63 on marine life in Britain. Journal of Animal Ecology, 33, 165-210.
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.
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.
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.
Holt, T.J., Hartnoll, R.G. & Hawkins, S.J., 1997. The sensitivity and vulnerability to man-induced change of selected communities: intertidal brown algal shrubs, Zostera beds and Sabellaria spinulosa reefs. English Nature, Peterborough, English Nature Research Report No. 234.
Irvine, L. M. & Chamberlain, Y. M., 1994. Seaweeds of the British Isles, vol. 1. Rhodophyta, Part 2B Corallinales, Hildenbrandiales. London: Her Majesty's Stationery Office.
Kain, J.M., 1975a. Algal recolonization of some cleared subtidal areas. Journal of Ecology, 63, 739-765.
O'Brien, P.J. & Dixon, P.S., 1976. Effects of oils and oil components on algae: a review. British Phycological Journal, 11, 115-142.
Peattie, M.E. & Hoare, R., 1981. The sublittoral ecology of the Menai Strait. II. The sponge Halichondria panicea (Pallas) and its associated fauna. Estuarine, Coastal and Shelf Science, 13, 621-635.
Peters, A.F. & Schaffelke, B., 1996. Streblonema (Ectocarpales, Phaeophyceae) infection in the kelp Laminaria saccharina in the western Baltic. Hydrobiologia, 326/327, 111-116.
Read, P.A., Anderson, K.J., Matthews, J.E., Watson, P.G., Halliday, M.C. & Shiells, G.M., 1983. Effects of pollution on the benthos of the Firth of Forth. Marine Pollution Bulletin, 14, 12-16.
Schmidt, G.H., 1983. The hydroid Tubularia larynx causing 'bloom' of the ascidians Ciona intestinalis and Ascidiella aspersa. Marine Ecology Progress Series, 12, 103-105.
This review can be cited as:
Last Updated: 30/11/2001