Loose-lying mats of Phyllophora crispa on infralittoral muddy sediment

Summary

UK and Ireland classification

Description

Infralittoral muddy sand and sandy mud, sometimes with some shells or pebbles, and a dense, loose-lying cover of Phyllophora crispa. This biotope occurs in very sheltered conditions such as those found in sealochs and voes. SMP.Pcri is similar to other biotopes described with dense, loose-lying algae but has been less frequently recorded, and from the few records available, appears to occur in slightly deeper infralittoral waters primarily between 10 m to 30 m and typically in fully saline waters. The seaweeds in this biotope may be epiphytised by ascidians such as Ascidiella aspera.Kelp such as Saccharina latissima and red seaweeds including Plocamium cartilagineum may be present in some areas. The scallops Pecten maximus and Aequipecten opercularis may also be found occasionally in this biotope and Trailliella / Bonnemaisonia hamifera may also be present but not at the levels found in SMP.Tra. (Information from Connor et al., 2004).

Depth range

5-10 m, 10-20 m, 20-30 m

Additional information

Little information on the biology of Phyllophora crispa was found. In addition, this biotope is unique and occurs in specific habitats, so that even less information on the ecology of the biotope was available. Therefore, the sensitivity assessments are based on the general biology of Phyllophora spp., the biotope description and expert judgement, and should be interpreted with caution.

Listed By

Sensitivity reviewHow is sensitivity assessed?

Sensitivity characteristics of the habitat and relevant characteristic species

This biotope (SMp.KSwSS.Pcri) is defined by the abundance of Phyllophora crispa in the form of dense loose-lying mats on infralittoral muddy sand and sandy mud in very wave sheltered conditions, typical of sea lochs and voes (Connor et al., 2004). The presence of other red algae and kelp varies between records of the biotope. Mobile crabs and urchins probably roam the surrounding area and epifaunal keel worms and hydroids are probably ubiquitous on any stones and pebbles in the surrounding area. The characteristic infauna is not reported except for Cerianthus lloydii which is found in many other sedimentary habitats. The remaining epiphytic ascidians and bryozoans are, by definition, dependent on the Phyllophora mat for substratum. Therefore, the sensitivity of the biotope is probably dependent on the sensitivity of the Phyllophora mat whose loss would result in loss of the biotope as described by the habitat classification.

Resilience and recovery rates of habitat

Phyllophora crispa is a perennial species growing from a small discoid holdfast. The growth form varies depending on environmental conditions but it is usually dichotomous branching with membranous or cartilaginous flat bladed fronds up to 10-15 cm in length, sometimes with up to 5-6 proliferations (Dixon & Irvine, 1977; Bunker et al., 2012; Guiry & Guiry, 2015). Dixon & Irvine (1977) noted that regeneration occurs in Phyllophora crispa after erosion or animal grazing. Molenaar & Breeman (1994) noted that Phyllophora pseudoceranoides exhibited annual growth and die back patterns where growth is removed annually by abrasion or water action leading to breakage.

Phyllophora crispa is dioecious but the gametophyte and tetrasporophyte are isomorphic. The male gametophytes release spermatangia in September to October, and female gametophytes develop cystocarps in September to March and release carpospores in January. The tetrasporangia are recorded in August to March and tetraspores are usually released in January (Newroth, 1972; Dixon & Irvine, 1977). Newroth (1972) reported that carposporelings of Phyllophora pseudoceranoides transferred from culture into the wild grew to a height of 3 cm in two years. The spores of red algae are non-motile (Norton, 1992) and therefore entirely reliant on the hydrographic regime for dispersal. Norton (1992) reviewed dispersal by macroalgae and concluded that dispersal potential is highly variable, recruitment usually occurs on a local scale, typically within 10 m of the parent plant. Hence, it is expected that the red algal turf would normally rely on recruitment from local individuals and that recovery of populations via spore settlement, where adults are removed, would be protracted.

‘Zernov’s Phyllophora field’ in the north-western Black Sea has undergone significant degradation between 1964 and 2004 due to eutrophication, resultant algal blooms and increased turbidity (BSC, 2008; Kostylev et al., 2010). The ‘field’ is composed of several species of Phyllophora including Phyllophora crispa. The Phyllophora field has remained but the abundance of the Phyllophora, the range of Phyllophora species, their age structure, the extent of the ‘field’, and the ecosystem of fish and other algae decreased or declined. However, an increase in species richness and extent of the ’field’ was reported from 2005 to 2007, so that regeneration had begun (Kostylev et al., 2010). BSC (2008) suggest that eutrophication and its effects stabilised in the 1990s and decreased in the 2000s.

Kain (1975) examined recolonization of artificially cleared areas in a Laminaria hyperborea forest in Port Erin, Isle of Man. Cleared concrete blocks were colonized by kelps and un-specified Rhodophyceae at 0.8 m. After about 2.5 years, Laminaria hyperborea standing crop, together with an understorey of red algae (Rhodophyceae), was similar to that of virgin forest. Rhodophyceae were present throughout the succession increasing from 0.04 to 1.5 percent of the biomass within the first 4 years. Succession was similar at 4.4 m, and Laminaria hyperborea dominated within about 3 years. Blocks cleared in August 1969 at 4.4m were dominated by Rhodophyceae after 41 weeks, e.g. Delesseria sanguinea and Cryptopleura ramosa. Kain (1975) cleared one group of blocks at two monthly intervals and noted that Phaeophyceae were dominant colonists in spring, Chlorophyceae (solely Ulva lactuca) in summer and Rhodophyceae were most important in autumn and winter.  However, Phyllophora crispa was not reported in her study.

Resilience assessment. No direct evidence of recovery was found. The growth rate of Phyllophora pseudoceranoides might suggest that Phyllophora crispa would take several years to recover its full length of 10-15 cm, although it is also reported to regenerate (Newroth, 1972; Dixon & Irvine, 1977). Recovery of the extensive field of Phyllophora spp. in the Black Sea does not provide a precise timeline but again suggests several years for recovery to begin. Therefore, where a proportion of the population of Phyllophora is removed or lost (i.e. resistance in ‘Medium’) then resilience is assumed to be High. However, where a significant proportion of the Phyllophora mat is lost or removed, resilience is assumed to be Medium (2-10 yrs) but with ‘Low’ confidence based on expert judgement and little supporting evidence.

Hydrological Pressures

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ResistanceResilienceSensitivity
Temperature increase (local) [Show more]

Temperature increase (local)

Benchmark. A 5°C increase in temperature for one month, or 2°C for one year. Further detail

Evidence

Phyllophora crispa is widely distributed on the coasts of the British Isles, except in the east of England. It is widely distributed in the east Atlantic with a northern limit in Iceland and a southern limit in North Africa but is also present in the Mediterranean and Black Sea (Newroth, 1971; Dixon & Irvine, 1977; Guiry & Guiry, 2015; Bunker et al., 2012). OBIS (2016) recorded Phyllophora crispa in waters of 8.5 to 14.5°C, although the derivation of the records is unclear. Kooistra et al. (1989) noted that it was limited to lower shore tide pools but concluded that temperature and salinity were not the limiting factors but that oxygenation and completion were possible limiting factors. However, Gallon et al. (2014) reported that changes in red seaweed assemblages across Brittany were correlated with a 0.7°C increase in coastal water temperature over the prior twenty years. Species varied in their response but the occurrence of several species of red algae, including Phyllophora crispa, increased.  

Sensitivity assessment.  Phyllophora crispa is distributed to the north and south of the British Isles and, therefore, is probably tolerant of a long-term 2°C change in temperature for a year. It is also likely to tolerate a 5°C change in the short-term. Therefore, a resistance of High is suggested so that resilience is High (by default) and the biotope is assessed as Not sensitive at the benchmark level.  However, confidence in the assessed in Low as it is based on expert judgment and proxies for evidence.

High
Low
NR
NR
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High
High
High
High
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Not sensitive
Low
Low
Low
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Temperature decrease (local) [Show more]

Temperature decrease (local)

Benchmark. A 5°C decrease in temperature for one month, or 2°C for one year. Further detail

Evidence

Phyllophora crispa is widely distributed on the coasts of the British Isles, except in the east of England. It is widely distributed in the east Atlantic with a northern limit in Iceland and a southern limit in North Africa but is also present in the Mediterranean and Black Sea (Newroth, 1971; Dixon & Irvine, 1977; Guiry & Guiry, 2015; Bunker et al., 2012). OBIS (2016) recorded Phyllophora crispa in waters of 8.5 to 14.5°C, although the derivation of the records is unclear. Kooistra et al. (1989) noted that it was limited to lower shore tide pools but concluded that temperature and salinity were not the limiting factors but that oxygenation and completion were possible limiting factors.

Sensitivity assessment.  Phyllophora crispa is distributed to the north and south of the British Isles and, therefore, is probably tolerant of a long-term 2°C change in temperature for a year. It is also likely to tolerate a 5°C change in the short-term. Therefore, a resistance of High is suggested so that resilience is High (by default) and the biotope is assessed as Not sensitive at the benchmark level.  However, confidence in the assessed in Low as it is based on expert judgment and proxies for evidence.

High
Low
NR
NR
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High
High
High
High
Help
Not sensitive
Low
Low
Low
Help
Salinity increase (local) [Show more]

Salinity increase (local)

Benchmark. A increase in one MNCR salinity category above the usual range of the biotope or habitat. Further detail

Evidence

Phyllophora crispa is recorded from shady places in the lower littoral, lower littoral pools and subtidally to ca 30m (Dixon & Irvine, 1977; Bunker et al., 20102). Kooistra et al. (1989) noted that Phyllophora crispa was limited to lower shore tide pools but concluded that temperature and salinity were not the limiting factors but that oxygenation and competition were possible limiting factors.  Maximova (2013; summary only) reported that ‘morphological and biological changes’ in Phyllophora crispa from the Black Sea changed in experiments where the ‘normal’ salinity was raised from 18 ppt to 25, 32 and 39, but no further details were available.  OBIS (2016) recorded Phyllophora crispa in waters of 17.9 to 38 pps, although the derivation of the records is unclear.

Sensitivity assessment.  The presence of Phyllophora crispa in the lower intertidal suggests that it might be exposed to changes in salinity due to evaporation or rainfall but only for very short periods.  This biotope (KSwSS.Pcri) is only recorded from full salinity so that an increase in salinity at the benchmark level would expose the biotope to hypersaline conditions, for example from hypersaline effluents.  However, no evidence on which to base and assessment was found.

No evidence (NEv)
NR
NR
NR
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Not relevant (NR)
NR
NR
NR
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No evidence (NEv)
NR
NR
NR
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Salinity decrease (local) [Show more]

Salinity decrease (local)

Benchmark. A decrease in one MNCR salinity category above the usual range of the biotope or habitat. Further detail

Evidence

Phyllophora crispa is recorded from shady places in the lower littoral, lower littoral pools and subtidally to ca 30m (Dixon & Irvine, 1977; Bunker et al., 20102). Kooistra et al. (1989) noted that Phyllophora crispa was limited to lower shore tide pools but concluded that temperature and salinity were not the limiting factors but that oxygenation and competition were possible limiting factors.  Maximova (2013; summary only) reported that ‘morphological and biological changes’ in Phyllophora crispa from the Black Sea changed in experiments where the ‘normal’ salinity was raised from 18 ppt to 25, 32 and 39, but no further details were available.  OBIS (2016) recorded Phyllophora crispa in waters of 17.9 to 38 pps, although the derivation of the records is unclear. A comparative study of salinity tolerances of macroalgae collected from North Zealand and the South Kattegat (Denmark) where salinity is 16 psu showed that species generally had a high tolerance (maintained more than half of photosynthetic capacity in short-term exposures of 4 days) to salinities lower than 3.7 psu. However, tolerances varied between species with Phyllophora pseudoceranoides exhibiting greater tolerance than Phycodrys rubens, which was the least resistant species tested (Larsen & Sand-Jensen, 2006).

Sensitivity assessment.  The presence of Phyllophora crispa in the lower intertidal suggests that it might be exposed to changes in salinity due to evaporation or rainfall but only for very short periods. This biotope (KSwSS.Pcri) is only recorded from full salinity so that a decrease in salinity at the benchmark level would expose the biotope to reduced salinity conditions (18-30 psu). The observations from the Black Sea, the South Kattegat and OBIS suggest that Phyllophora crispa could survive reduced salinity conditions but the biotope would probably experience a reduction in species richness and less resistant species left or were lost from the biotope. Therefore, a resistance of Medium is suggested. Resilience is probably High so that sensitivity is assessed as Low at the benchmark level. However, confidence in the assessed in Low as it is based on expert judgment and proxies for evidence.

Medium
Low
NR
NR
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High
Low
NR
NR
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Low
Low
Low
Low
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Water flow (tidal current) changes (local) [Show more]

Water flow (tidal current) changes (local)

Benchmark. A change in peak mean spring bed flow velocity of between 0.1 m/s to 0.2 m/s for more than one year. Further detail

Evidence

Phyllophora crispa was recorded from moderately strong to very weak tidal flow (Connor et al., 2004). It has been recorded to regenerate after erosion (Dixon & Irvine, 1977) while Molenaar & Breeman (1994) noted that Phyllophora pseudoceranoides exhibited annual growth and die back patterns where growth was removed annually by abrasion or water action.  However, this biotope is unusual because the very weak to weak tidal streams and very wave sheltered conditions allow Phyllophora crispa to grow abundantly on fine sediments (muddy sands and sandy muds).  It is presumably attached to small stones  within the sediment.  A significant increase in water flow may winnow away the mud surface or even remove the mud habitat and hence the biotope if prolonged. An increase of 0.2 m/s may begin to erode the mud surface where the site is already subject to flow (e.g. weak flow at the seabed), based on sediment erosion deposition curves (Wright, 2001). Therefore, an increase in water flow could result in the loss of the ‘loose-lying’ mat of Phyllophora crispa.  However, an increase of only 0.1-0.2 m/s may only affect example of the biotope already in weak flow, rather than very weak flow and a resistance of Low is suggested with Low confidence. Resilience is probably Medium so that sensitivity is assessed as Medium.

Low
Low
NR
NR
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Medium
Low
NR
NR
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Medium
Low
Low
Low
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Emergence regime changes [Show more]

Emergence regime changes

Benchmark.  1) A change in the time covered or not covered by the sea for a period of ≥1 year or 2) an increase in relative sea level or decrease in high water level for ≥1 year. Further detail

Evidence

Changes in emergence are ‘Not relevant’ to this biotope, which is restricted to fully subtidal habitats. The pressure benchmark is relevant only to littoral and shallow sublittoral fringe biotopes.

Not relevant (NR)
NR
NR
NR
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Not relevant (NR)
NR
NR
NR
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Not relevant (NR)
NR
NR
NR
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Wave exposure changes (local) [Show more]

Wave exposure changes (local)

Benchmark. A change in near shore significant wave height of >3% but <5% for more than one year. Further detail

Evidence

Phyllophora crispa was recorded from wave exposed to very wave sheltered sites (Connor et al., 2004). It has been recorded to regenerate after erosion (Dixon & Irvine, 1977) while Molenaar & Breeman (1994) noted that Phyllophora pseudoceranoides exhibited annual growth and die back patterns where growth was removed annually by abrasion or water action.  However, this biotope is unusual because the very weak to weak tidal streams and very wave sheltered conditions allow Phyllophora crispa to grow abundantly on fine sediments (muddy sands and sandy muds).  It is presumably attached to small stones within the sediment.  A further decrease in wave exposure is unlikely to affect the biotope. However, an increase in wave exposure is likely to remove the loose-lying mat of Phyllophora crispa but a 3-5% change in significant wave height (the benchmark) is unlikely to have a significant effect. Therefore, the biotope is probably Not sensitive (resistance and resilience are High) at the benchmark level. 

High
Low
NR
NR
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High
High
High
High
Help
Not sensitive
Low
Low
Low
Help

Chemical Pressures

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ResistanceResilienceSensitivity
Transition elements & organo-metal contamination [Show more]

Transition elements & organo-metal contamination

Benchmark. Exposure of marine species or habitat to one or more relevant contaminants via uncontrolled releases or incidental spills. Further detail

Evidence

This pressure is Not assessed but evidence is presented where available.

Not Assessed (NA)
NR
NR
NR
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Not assessed (NA)
NR
NR
NR
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Not assessed (NA)
NR
NR
NR
Help
Hydrocarbon & PAH contamination [Show more]

Hydrocarbon & PAH contamination

Benchmark. Exposure of marine species or habitat to one or more relevant contaminants via uncontrolled releases or incidental spills. Further detail

Evidence

This pressure is Not assessed but evidence is presented where available.

Not Assessed (NA)
NR
NR
NR
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Not assessed (NA)
NR
NR
NR
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Not assessed (NA)
NR
NR
NR
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Synthetic compound contamination [Show more]

Synthetic compound contamination

Benchmark. Exposure of marine species or habitat to one or more relevant contaminants via uncontrolled releases or incidental spills. Further detail

Evidence

This pressure is Not assessed but evidence is presented where available.

Not Assessed (NA)
NR
NR
NR
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Not assessed (NA)
NR
NR
NR
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Not assessed (NA)
NR
NR
NR
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Radionuclide contamination [Show more]

Radionuclide contamination

Benchmark. An increase in 10µGy/h above background levels. Further detail

Evidence

No evidence was found

No evidence (NEv)
NR
NR
NR
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Not relevant (NR)
NR
NR
NR
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No evidence (NEv)
NR
NR
NR
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Introduction of other substances [Show more]

Introduction of other substances

Benchmark. Exposure of marine species or habitat to one or more relevant contaminants via uncontrolled releases or incidental spills. Further detail

Evidence

This pressure is Not assessed.

Not Assessed (NA)
NR
NR
NR
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Not assessed (NA)
NR
NR
NR
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Not assessed (NA)
NR
NR
NR
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De-oxygenation [Show more]

De-oxygenation

Benchmark. Exposure to dissolved oxygen concentration of less than or equal to 2 mg/l for one week (a change from WFD poor status to bad status). Further detail

Evidence

Kooistra et al. (1989) noted that Phyllophora crispa was limited to lower shore tide pools but concluded that temperature and salinity were not the limiting factors but that oxygenation and competition were possible limiting factors.  However, no direct evidence was found.

No evidence (NEv)
NR
NR
NR
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Not relevant (NR)
NR
NR
NR
Help
No evidence (NEv)
NR
NR
NR
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Nutrient enrichment [Show more]

Nutrient enrichment

Benchmark. Compliance with WFD criteria for good status. Further detail

Evidence

‘Zernov’s Phyllophora field’ in the north-western Black Sea has undergone significant degradation between 1964 and 2004 due to eutrophication, resultant algal blooms and increased turbidity (BSC, 2008; Kostylev et al., 2010). The ‘field’ is composed of several species of Phyllophora including Phyllophora crispa. The Phyllophora field has remained but the abundance of the Phyllophora, the range of Phyllophora species, their age structure, the extent of the ‘field’, and the ecosystem of fish and other algae decreased or declined. Although the Black Sea is a unique environment, the results suggest that nutrient enrichment could affect the biotope and its associated community adversely.  Nevertheless, this biotope is considered to be 'Not sensitive' at the pressure benchmark that assumes compliance with good status as defined by the WFD.

Not relevant (NR)
NR
NR
NR
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Not relevant (NR)
NR
NR
NR
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Not sensitive
NR
NR
NR
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Organic enrichment [Show more]

Organic enrichment

Benchmark. A deposit of 100 gC/m2/yr. Further detail

Evidence

‘Zernov’s Phyllophora field’ in the north-western Black Sea has undergone significant degradation between 1964 and 2004 due to eutrophication, resultant algal blooms and increased turbidity (BSC, 2008; Kostylev et al., 2010). The ‘field’ is composed of several species of Phyllophora including Phyllophora crispa. The Phyllophora field has remained but the abundance of the Phyllophora, the range of Phyllophora species, their age structure, the extent of the ‘field’, and the ecosystem of fish and other algae decreased or declined.  It is unclear if the eutrophication in the Black Sea resulted from nutrients, organic loading, or both. Therefore, in the absence of clear evidence no assessment has been made.

No evidence (NEv)
NR
NR
NR
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Not relevant (NR)
NR
NR
NR
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No evidence (NEv)
NR
NR
NR
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Physical Pressures

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ResistanceResilienceSensitivity
Physical loss (to land or freshwater habitat) [Show more]

Physical loss (to land or freshwater habitat)

Benchmark. A permanent loss of existing saline habitat within the site. Further detail

Evidence

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
High
High
High
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Very Low
High
High
High
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High
High
High
High
Help
Physical change (to another seabed type) [Show more]

Physical change (to another seabed type)

Benchmark. Permanent change from sedimentary or soft rock substrata to hard rock or artificial substrata or vice-versa. Further detail

Evidence

If sedimentary substrata were replaced with rock substrata the biotope would be lost, as it would not longer be a sedimentary habitat.

Sensitivity assessment. Resistance to the pressure is considered ’None‘, and resilience ’Very low‘ or ‘None’ (as the pressure represents a permanent change) and the sensitivity of this biotope is assessed as ’High’.

None
High
High
High
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Very Low
High
High
High
Help
High
High
High
High
Help
Physical change (to another sediment type) [Show more]

Physical change (to another sediment type)

Benchmark. Permanent change in one Folk class (based on UK SeaMap simplified classification). Further detail

Evidence

This biotope is recorded from sandy gravelly muds (Connor et al., 2004, sediment matrix). Phyllophora crispa is found on other substrata, including rock and other seaweeds. The low energy environment of the biotope, i.e. low water flow and wave sheltered conditions, determines the nature of the sediment. The muddy sediment is probably inhospitable to most other macroalgae so that Phyllophora can become abundant. A change in sediment from sand muddy gravels to gravel or mud may not affect the biotope adversely. Bunker et al. (2012) note that Phyllophora crispa thrives on rock subject to shell gravel. Therefore, in the very sheltered condition so of this biotope, the mat of Phyllophora would probably survive on gravel or on muds where enough stone for attachment remains. Therefore, the biotope is probably Not sensitive (resistance and resilience are High) at the benchmark level. 

High
Low
NR
NR
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High
High
High
High
Help
Not sensitive
Low
Low
Low
Help
Habitat structure changes - removal of substratum (extraction) [Show more]

Habitat structure changes - removal of substratum (extraction)

Benchmark. The extraction of substratum to 30 cm (where substratum includes sediments and soft rock but excludes hard bedrock). Further detail

Evidence

The biotope is an epifloral mat sitting on the surface of the sediment. Extraction of the sediment to any depth would result in removal of the Phyllophora mat from the affected area.  Therefore, a resistance of None is suggested. Resilience is probably Medium and sensitivity is assessed as Medium but with Low confidence due to the lack of any direct evidence.

None
Low
NR
NR
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Medium
Low
NR
NR
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Medium
Low
Low
Low
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Abrasion / disturbance of the surface of the substratum or seabed [Show more]

Abrasion / disturbance of the surface of the substratum or seabed

Benchmark. Damage to surface features (e.g. species and physical structures within the habitat). Further detail

Evidence

Dixon & Irvine (1977) noted that Phyllophora crispa regenerates after erosion and animal grazing. Bunker et al. (2012) noted that it tolerated sediment cover and thrived in areas subject to shell gravel.  Both observations suggest that it can either resist or regrow from damage due to sediment scour or animal grazing.  However, this biotope (KSwSS.Pcri) is an epifloral mat sitting on the surface of sediment; probably loosely attaché to small stones or shells in the sediment.  Any passing bottom gear is liable to remove the mat of Phyllophora. Therefore, a resistance of Low is suggested. Resilience is probably Medium so that the sensitivity is assessed as Medium at the benchmark level but with Low confidence due to the lack of any direct evidence.

Low
Low
NR
NR
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Medium
Low
NR
NR
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Medium
Low
Low
Low
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Penetration or disturbance of the substratum subsurface [Show more]

Penetration or disturbance of the substratum subsurface

Benchmark. Damage to sub-surface features (e.g. species and physical structures within the habitat). Further detail

Evidence

Dixon & Irvine (1977) noted that Phyllophora crispa regenerates after erosion and animal grazing. Bunker et al. (2012) noted that it tolerated sediment cover and thrived in areas subject to shell gravel.  Both observations suggest that it can either resist or regrow from damage due to sediment scour or animal grazing.  However, this biotope (KSwSS.Pcri) is an epifloral mat sitting on the surface of sediment; probably loosely attaché to small stones or shells in the sediment.  Any passing bottom gear is liable to remove the mat of Phyllophora. Therefore, a resistance of Low is suggested. Resilience is probably Medium so that the sensitivity is assessed as Medium at the benchmark level but with Low confidence due to the lack of any direct evidence.

Low
Low
NR
NR
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Medium
Low
NR
NR
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Medium
Low
NR
NR
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Changes in suspended solids (water clarity) [Show more]

Changes in suspended solids (water clarity)

Benchmark. A change in one rank on the WFD (Water Framework Directive) scale e.g. from clear to intermediate for one year. Further detail

Evidence

Red algae are shade tolerant macroalgae. Phyllophora crispa is particularly shade tolerant and is recorded a greater depths than many other red algae. For example, Smith & Jones (1970) reported that Phyllophora crispa grew at a greater depth (25 m) than other red algae examined on the west coast of Anglesey and Norton (1968) reported it at 33 m at St Mary’s Isles of Scilly. Norton et al. (1971) noted that Phyllophora crispa penetrated up to 15 m in a sea cave (Bullock Island Cave, near Lough Ine), although its growth was stunted at its limit into the cave. The degradation of ‘Zernov’s Phyllophora field’ in the north-western Black Sea was attributed to eutrophication, algal blooms and turbidity. All three species of Phyllophora present survived but their biomass was reduced by an order to magnitude (Kostylev et al., 2010).  Therefore, it is likely that an increase in turbidity due to suspended solids could result in a loss of a proportion of the population of Phyllophora crispa, especially in the deeper examples of the biotope and a resistance of Low is suggested. Resilience is probably Medium so that sensitivity is assessed as Medium.

Low
High
Medium
Medium
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Medium
Low
NR
NR
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Medium
Low
Low
Low
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Smothering and siltation rate changes (light) [Show more]

Smothering and siltation rate changes (light)

Benchmark. ‘Light’ deposition of up to 5 cm of fine material added to the seabed in a single discrete event. Further detail

Evidence

Airoldi (2003) identified a number of morphological, physiological and life history traits that conferred high levels of tolerance to sedimentation. For example, regeneration of upright fronds from a perennial basal crust resistant to burial and scour, calcified thalli, apical meristems, large reproductive outputs, lateral vegetative growth and slow growth rates (Airoldi, 2003). Algae with tough thalli are more resistant to sedimentation and scour (Pedersén & Snoeijs, 2001). Phyllophora crispa was reported to regenerate after erosion and animal grazing (Dixon & Irvine, 1977) and Bunker et al. (2012) noted that it tolerated sediment cover and thrived in areas subject to shell gravel.  Both observations suggest that it can either resist or regrow from damage due to sediment scour.  However, in the wave sheltered, low energy conditions that typify this biotope any deposit of sediment is likely to remain and smother the biotope. 

Sensitivity assessment. Phyllophora crispa grows up to 15 cm in length, and could probably either protrude through 5 cm of deposited sediment or grow up through it.  Therefore, a resistance of High is suggested. Resilience is, therefore, High and the biotope is probably Not sensitive at the benchmark level.

High
Low
NR
NR
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High
High
High
High
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Not sensitive
Low
Low
Low
Help
Smothering and siltation rate changes (heavy) [Show more]

Smothering and siltation rate changes (heavy)

Benchmark. ‘Heavy’ deposition of up to 30 cm of fine material added to the seabed in a single discrete event. Further detail

Evidence

Airoldi (2003) identified a number of morphological, physiological and life history traits that conferred high levels of tolerance to sedimentation. For example, regeneration of upright fronds from a perennial basal crust resistant to burial and scour, calcified thalli, apical meristems, large reproductive outputs, lateral vegetative growth and slow growth rates (Airoldi, 2003). Algae with tough thalli are more resistant to sedimentation and scour (Pedersén & Snoeijs, 2001). Phyllophora crispa was reported to regenerate after erosion and animal grazing (Dixon & Irvine, 1977) and Bunker et al. (2012) noted that it tolerated sediment cover and thrived in areas subject to shell gravel.  Both observations suggest that it can either resist or regrow from damage due to sediment scour.  However, in the wave sheltered, low energy conditions that typify this biotope any deposit of sediment is likely to remain and smother the biotope. 

Sensitivity assessment. Phyllophora crispa grows up to 15 cm in length and would be completely smothered by 30 cm of deposited sediment.  The sediment is likely to remain, and the plants will be removed from light and probably succumb to localise anoxia under the sediment. Therefore, a resistance of None is suggested. Resilience is probably Medium and the sensitivity is assessed as Medium benchmark level.

None
Low
NR
NR
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Medium
Low
NR
NR
Help
Medium
Low
Low
Low
Help
Litter [Show more]

Litter

Benchmark. The introduction of man-made objects able to cause physical harm (surface, water column, seafloor or strandline). Further detail

Evidence

Not assessed.

Not Assessed (NA)
NR
NR
NR
Help
Not assessed (NA)
NR
NR
NR
Help
Not assessed (NA)
NR
NR
NR
Help
Electromagnetic changes [Show more]

Electromagnetic changes

Benchmark. A local electric field of 1 V/m or a local magnetic field of 10 µT. Further detail

Evidence

No evidence was found

No evidence (NEv)
NR
NR
NR
Help
Not relevant (NR)
NR
NR
NR
Help
No evidence (NEv)
NR
NR
NR
Help
Underwater noise changes [Show more]

Underwater noise changes

Benchmark. MSFD indicator levels (SEL or peak SPL) exceeded for 20% of days in a calendar year. Further detail

Evidence

Not relevant

Not relevant (NR)
NR
NR
NR
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Not relevant (NR)
NR
NR
NR
Help
Not relevant (NR)
NR
NR
NR
Help
Introduction of light or shading [Show more]

Introduction of light or shading

Benchmark. A change in incident light via anthropogenic means. Further detail

Evidence

Red algae are shade tolerant macroalgae. Phyllophora crispa is particularly shade tolerant and is recorded a greater depths than many other red algae. For example, Smith & Jones (1970) reported that Phyllophora crispa grew at a greater depth (25 m) than other red algae examined on the west coast of Anglesey and Norton (1968) reported it at 33 m at St Mary’s Isles of Scilly. Norton et al. (1971) noted that Phyllophora crispa penetrated up to 15 m in a sea cave (Bullock Island Cave, near Lough Ine), although its growth was stunted at its limit into the cave. The degradation of ‘Zernov’s Phyllophora field’ in the north western Black Sea was attributed to eutrophication, algal blooms and turbidity. All three species of Phyllophora present survived but their biomass was reduced by an order to magnitude (Kostylev et al., 2010).  Therefore, shading by an artificial structure may reduce photosynthesis (depending on intensity and duration), and may reduce the abundance of algae, although Phyllophora will probably survive.  Therefore, a resistance of Medium is suggested, with a resilience of High and a sensitivity of Low. However, permanent shading may reduce the depth to which the biotope can grow, resulting in loss of deeper example of the biotope.  The biotope occurs below 5 m so that artificial lighting is unlikely to penetrate the water column enough to affect photosynthesis.

Medium
Medium
Medium
Medium
Help
High
Low
NR
NR
Help
Low
Low
NR
NR
Help
Barrier to species movement [Show more]

Barrier to species movement

Benchmark. A permanent or temporary barrier to species movement over ≥50% of water body width or a 10% change in tidal excursion. Further detail

Evidence

Not relevant

Not relevant (NR)
NR
NR
NR
Help
Not relevant (NR)
NR
NR
NR
Help
Not relevant (NR)
NR
NR
NR
Help
Death or injury by collision [Show more]

Death or injury by collision

Benchmark. Injury or mortality from collisions of biota with both static or moving structures due to 0.1% of tidal volume on an average tide, passing through an artificial structure. Further detail

Evidence

The pressure definition is not directly applicable to seabed biotopes so Not relevant has been recorded.  Collision via ship groundings or terrestrial vehicles is possible but the effects are probably similar to those of abrasion above.

Not relevant (NR)
NR
NR
NR
Help
Not relevant (NR)
NR
NR
NR
Help
Not relevant (NR)
NR
NR
NR
Help
Visual disturbance [Show more]

Visual disturbance

Benchmark. The daily duration of transient visual cues exceeds 10% of the period of site occupancy by the feature. Further detail

Evidence

Not relevant

Not relevant (NR)
NR
NR
NR
Help
Not relevant (NR)
NR
NR
NR
Help
Not relevant (NR)
NR
NR
NR
Help

Biological Pressures

Use [show more] / [show less] to open/close text displayed

ResistanceResilienceSensitivity
Genetic modification & translocation of indigenous species [Show more]

Genetic modification & translocation of indigenous species

Benchmark. Translocation of indigenous species or the introduction of genetically modified or genetically different populations of indigenous species that may result in changes in the genetic structure of local populations, hybridization, or change in community structure. Further detail

Evidence

No evidence was found of the translocation, breeding or species hybridization of the important characterizing species.

No evidence (NEv)
NR
NR
NR
Help
Not relevant (NR)
NR
NR
NR
Help
No evidence (NEv)
NR
NR
NR
Help
Introduction or spread of invasive non-indigenous species [Show more]

Introduction or spread of invasive non-indigenous species

Benchmark. The introduction of one or more invasive non-indigenous species (INIS). Further detail

Evidence

Bonnemaisonia hamifera (and the Trailliella-phase) is a non-native species introduced to the British Isles from Japan and first recorded in 1890 (Dixon & Irvine, 1977; Maggs & Stegenga, 1998; Gollasch, 2006).  It is thought to have been introduced by shipping or with shellfish and to have dispersed by drifting on water currents (Gollasch, 2006).  Bonnemaisonia hamifera (and the Trailliella-phase) has spread around the British Isles and Europe, into the Mediterranean and the Canary Isles and north to the Orkneys and the Norwegian coast (Lüning, 1990, Maggs & Stegenga, 1998; Gollasch, 2006).  It grows rapidly, reproduces vegetatively, and can spread by fragmentation and drifting (Maggs & Stegenga, 1998).

Bonnemaisonia hamifera (and the Trailliella-phase) occurs in this biotope with Phyllophora crispa but at a lower abundance than its characteristic biotope (KSwSS.Tra). KSwSS.Tra occurs in shallower waters but otherwise similar conditions. Therefore, if the abundance of Phyllophora crispa was reduced by an external factor then the Trailliella might be about to take over the available space, especially in the shallow examples of the biotope (KSwSS.Pcri). However, there is no evidence that this has happened to date.  Therefore, a precautionary resistance of Medium is suggested but with a ‘Low’ confidence. Resilience is probably High so that sensitivity is assessed as Low.

Medium
Low
NR
NR
Help
High
Low
NR
NR
Help
Low
Low
Low
Low
Help
Introduction of microbial pathogens [Show more]

Introduction of microbial pathogens

Benchmark. The introduction of relevant microbial pathogens or metazoan disease vectors to an area where they are currently not present (e.g. Martelia refringens and Bonamia, Avian influenza virus, viral Haemorrhagic Septicaemia virus). Further detail

Evidence

No evidence was found.

No evidence (NEv)
NR
NR
NR
Help
Not relevant (NR)
NR
NR
NR
Help
No evidence (NEv)
NR
NR
NR
Help
Removal of target species [Show more]

Removal of target species

Benchmark. Removal of species targeted by fishery, shellfishery or harvesting at a commercial or recreational scale. Further detail

Evidence

Phyllophora crispa is unlikely to be targetted by any commercial or recreational fishery or harvest.

Not relevant (NR)
NR
NR
NR
Help
Not relevant (NR)
NR
NR
NR
Help
Not relevant (NR)
NR
NR
NR
Help
Removal of non-target species [Show more]

Removal of non-target species

Benchmark. Removal of features or incidental non-targeted catch (by-catch) through targeted fishery, shellfishery or harvesting at a commercial or recreational scale. Further detail

Evidence

Accidental physical disturbance due to access (e.g. trampling), grounding, or passing fishing gear is examined under abrasion above. However, the accidental removal of the Phyllophora mat would result in a significant change in the biological character of, and loss of, the biotope. Therefore, a resistance of None is suggested. Resilience is probably Medium so that sensitivity is assessed as Medium but with 'Low' confidence.

None
Low
NR
NR
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Medium
Low
NR
NR
Help
Medium
Low
Low
Low
Help

Bibliography

  1. Airoldi, L., 2003. The effects of sedimentation on rocky coast assemblages. Oceanography and Marine Biology: An Annual Review, 41,161-236

  2. BSC (Black sea Commission), 2008. State of the Environment of the Black Sea (2001 - 2006/7), (ed Temel Oguz). Publications of the Commission on the Protection of the Black Sea Against Pollution (BSC) 2008-3, Istanbul, Turkey, 448 pp. Avaialable from http://www.blacksea-commission.org/_publ-SOE2009.asp

  3. Bunker, F.StD.P., Maggs, C.A., Brodie, J.A. & Bunker, A.R., 2012. Seasearch Guide to Seaweeds of Britain and Ireland. Plymouth: Wild Nature Press.

  4. Connor, D.W., Allen, J.H., Golding, N., Howell, K.L., Lieberknecht, L.M., Northen, K.O. & Reker, J.B., 2004. The Marine Habitat Classification for Britain and Ireland. Version 04.05. ISBN 1 861 07561 8. In JNCC (2015), The Marine Habitat Classification for Britain and Ireland Version 15.03. [2019-07-24]. Joint Nature Conservation Committee, Peterborough. Available from https://mhc.jncc.gov.uk/

  5. Dixon, P.S. & Irvine, L.M., 1977. Seaweeds of the British Isles. Volume 1 Rhodophyta. Part 1 Introduction, Nemaliales, Gigartinales. London: British Museum (Natural History) London.

  6. Gallon, R.K., Robuchon, M., Leroy, B., Le Gall, L., Valero, M. & Feunteun, E., 2014. Twenty years of observed and predicted changes in subtidal red seaweed assemblages along a biogeographical transition zone: inferring potential causes from environmental data. Journal of Biogeography, 41(12), 2293-2306.

  7. Guiry, M.D. & Guiry, G.M. 2015. AlgaeBase [Online], National University of Ireland, Galway [cited 30/6/2015]. Available from: http://www.algaebase.org/

  8. JNCC (Joint Nature Conservation Committee), 2022.  The Marine Habitat Classification for Britain and Ireland Version 22.04. [Date accessed]. Available from: https://mhc.jncc.gov.uk/

  9. Kain, J.M., 1975a. Algal recolonization of some cleared subtidal areas. Journal of Ecology, 63, 739-765.

  10. Kostylev, E.F., Tkachenko, F.P. & Tretiak, I.P., 2010. Establishment of “Zernov’s Phyllophora field” marine reserve: Protection and restoration of a unique ecosystem. Ocean & Coastal Management, 53 (5–6), 203-208.

  11. Larsen, A. & Sand-Jensen, K., 2006. Salt tolerance and distribution of estuarine benthic macroalgae in the Kattegat-Baltic Sea area. Phycologia, 45 (1), 13-23.

  12. Maggs, C.A. & Stegenga, H., 1998. Red algal exotics on North Sea coasts. Helgoländer Meeresuntersuchungen, 52 (3), 243-258.

  13. Maximova, O.V., 2013. Salinity and marine macroalgae: eco-morphological plasticity in vitro and in situ. Trudy Zoologicheskogo Instituta, 317 (Suppl. 3), 168-174.

  14. Molenaar, F.J. & Breeman, A.M., 1994. Ecotypic variation in Phyllophora pseudoceranoides (Rhodophyta) ensures winter reproduction throughout its geographic range. Journal of Phycology, 30 (3), 392-402.

  15. Newroth, P.R., 1972. Studies on life histories in the Phyllophoraceae. II. Phyllophora pseudoceranoides and notes on P. crispa and P. heredia (Rhodophyta, Gigartinales). Phycologia, 11 (2), 99-107.

  16. Newroth, P.R., 1971. Distribution of Phyllophora in North Atlantic and Arctic regions. Canadian Journal of Botany, 49 (6), 1017-1024.

  17. Norton, T.A., 1968. Underwater observations on the vertical distribution of algae at St Mary's, Isles of Scilly. British Phycological Bulletin, 3 (3), 585-588.

  18. Norton, T.A., 1992. Dispersal by macroalgae. British Phycological Journal, 27, 293-301.

  19. Norton, T.A., Ebling, F.J. & Kitching, J.A., 1971. Light and the distribution of organisms in a sea cave.  In Proceedings of the Fourth European Marine Biology Symposium, 14-20 September, Bangor, North Wales (ed D.J. Crisp), pp. 409-432. Cambridge: Cambridge University Press.

  20. Pedersen, M. & Snoeijs, P., 2001. Patterns of macroalgal diversity, community composition and long-term changes along the Swedish west coast. Hydrobiologia, 459 (1-3), 83-102.

  21. Smith, R.M. & Jones, W.E., 1970. The culture of benthic marine algae in the laboratory and the field. Helgolander Wissenschaftliche Meeresuntersuchungen, 20 (1), 62-69.

  22. Wright, J., Colling, A., Park, D. & Open University Oceanography Course Team, 2001. Waves, Tides, and Shallow-water Processes.  Oxford: Butterworth-Heinemann.

Citation

This review can be cited as:

Tyler-Walters, H., 2016. Loose-lying mats of Phyllophora crispa on infralittoral muddy sediment. In Tyler-Walters H. and Hiscock K. Marine Life Information Network: Biology and Sensitivity Key Information Reviews, [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 25-05-2024]. Available from: https://marlin.ac.uk/habitat/detail/187

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Last Updated: 22/06/2016