The Marine Life Information Network

Substratum loss

Benchmark. All of the substratum occupied by the species or biotope under consideration is removed. A single event is assumed for sensitivity assessment. Once the activity or event has stopped (or between regular events) suitable substratum remains or is deposited. Species or community recovery assumes that the substratum within the habitat preferences of the original species or community is present. Further details

Evidence

Plants will be removed with the substratum and therefore intolerance is high. Recoverability is expected to be very high: see additional information below.

Smothering

Benchmark. All of the population of a species or an area of a biotope is smothered by sediment to a depth of 5 cm above the substratum for one month. Impermeable materials, such as concrete, oil, or tar, are likely to have a greater effect. Further details.

Evidence

Ceramium virgatum is an erect species which grows up to 20 cm in length. Filamentous algae generally have delicate thalli and can therefore be expected to be sensitive to smothering (F. Rindi, pers. comm.). In addition, developing propagules are likely to be buried by 5 cm of sediment and would be unable to photosynthesize. For example, Vadas et al. (1992) stated that algal spores and propagules are adversely affected by a layer of sediment, which can exclude up to 98% of light. There is therefore likely to be some mortality of the population and intolerance is assessed as intermediate. Recoverability is expected to be very high: see additional information below.

Increase in suspended sediment

Benchmark. An arbitrary short-term, acute change in background suspended sediment concentration e.g., a change of 100 mg/l for one month. The resultant light attenuation effects are addressed under turbidity, and the effects of rapid settling out of suspended sediment are addressed under smothering. Further details

Evidence

Ceramium virgatum is not likely to be affected directly by an increase in suspended sediment. However, increased suspended sediment will increase light attenuation (considered in 'turbidity') and siltation. As discussed above in 'smothering', increased rate of siltation may inhibit development of algal spores and propagules resulting in some mortality. However, Hily et al. (1992) observed that, in conditions of high turbidity, Ceramium virgatum (as C. rubrum) (and Ulva sp.) dominated sediments in the Bay of Brest, France. The effects of increased suspended sediment are therefore equivocal but, because some deeper populations are likely to be adversely affected by reduction in light penetration and because of possible smothering, overall an intolerance of intermediate is suggested. Recovery is expected to be very high: see additional information below.

Decrease in suspended sediment

Benchmark. An arbitrary short-term, acute change in background suspended sediment concentration e.g., a change of 100 mg/l for one month. The resultant light attenuation effects are addressed under turbidity, and the effects of rapid settling out of suspended sediment are addressed under smothering. Further details

Evidence

Ceramium virgatum is likely to benefit from a decrease in suspended sediment through effects of increased light penetration (see decreased turbidity below).

Desiccation

1. A normally subtidal, demersal or pelagic species including intertidal migratory or under-boulder species is continuously exposed to air and sunshine for one hour.
2. A normally intertidal species or community is exposed to a change in desiccation equivalent to a change in position of one vertical biological zone on the shore, e.g., from upper eulittoral to the mid eulittoral or from sublittoral fringe to lower eulittoral for a period of one year. Further details.

Evidence

Ceramium virgatum occurs profusely in rockpools, on the lower shore and in the subtidal but not on the open shore away from damp places suggesting that it is intolerant of desiccation. Recovery is expected to be very high: see additional information below.

Increase in emergence regime

Benchmark. A one hour change in the time covered or not covered by the sea for a period of one year. Further details

Evidence

Ceramium virgatum occurs on the lower shore and in the subtidal suggesting that it is intolerant of high amounts of emergence. Recovery is expected to be very high: see additional information below.

Decrease in emergence regime

Benchmark. A one hour change in the time covered or not covered by the sea for a period of one year. Further details

Evidence

Ceramium virgatum occurs predominantly in rockpools and in the subtidal and could potentially benefit from a decrease in emergence regime.

Increase in water flow rate

A change of two categories in water flow rate (view glossary) for 1 year, for example, from moderately strong (1-3 knots) to very weak (negligible). Further details

Evidence

Moderate water movement is beneficial to seaweeds as it carries a supply of nutrients and gases to the plants, removes waste products, and prevents settling of silt. However, if flow becomes too strong, plants may be displaced. Additionally, an increase to stronger flows may inhibit settlement of spores and remove adults or germlings. It is likely therefore that the benchmark increase in water flow rate to 'strong' or 'very strong' flow would result in some mortality, particularly of older individuals or those attached to the least stable substrata. Intolerance is therefore assessed as intermediate. Recoverability is recorded as very high (see additional information below).

Decrease in water flow rate

A change of two categories in water flow rate (view glossary) for 1 year, for example, from moderately strong (1-3 knots) to very weak (negligible). Further details

Evidence

Ceramium virgatum occurs in conditions of weak or very weak tidal streams (for instance, it is characteristic in the biotope 'Laminaria saccharina and Laminaria digitata on sheltered sublittoral fringe rock - SIR.Lsac.Ldig' (Connor et al. 1997a) and is recorded from some of the most sheltered parts of Hardangerfjord in Norway (Jorde & Klavestad, 1963). It is therefore expected that, providing stagnation and deoxygenation do not occur, the species will be not sensitive.

Increase in temperature

1. A short-term, acute change in temperature; e.g., a 5°C change in the temperature range for three consecutive days. This definition includes ‘short-term’ thermal discharges.
2. A long-term, chronic change in temperature; e.g. a 2°C change in the temperature range for a year. This definition includes ‘long term’ thermal discharges.

For intertidal species or communities, the range of temperatures includes the air temperature regime for that species or community. Further details

Evidence

Lüning (1990) records that Ceramium virgatum (as rubrum) survives at temperatures from 0 to 25°C with optimal growth at about 15°C. The species is therefore likely to be tolerant of higher temperatures than it experiences in the seas around Britain and Ireland. Temperatures in rockpools are recorded by Morris & Taylor (1983) and by Goss-Custard et al. (1979) as rising to or slightly above 25°C. However, rockpool temperatures could rise significantly above 25°C and some mortality may occur in exceptional conditions. Photosynthesis and growth may also be compromised by high temperatures. Intolerance is therefore recorded as low. Physiological processes should quickly return to normal when temperatures return to their original levels so recoverability is recorded as very high.

Decrease in temperature

1. A short-term, acute change in temperature; e.g., a 5°C change in the temperature range for three consecutive days. This definition includes ‘short-term’ thermal discharges.
2. A long-term, chronic change in temperature; e.g. a 2°C change in the temperature range for a year. This definition includes ‘long term’ thermal discharges.

For intertidal species or communities, the range of temperatures includes the air temperature regime for that species or community. Further details

Evidence

Lüning (1990) records that Ceramium virgatum (as rubrum) survives at temperatures from 0 to 25°C with optimal growth at about 15°C. The species is therefore likely to be tolerant of lower temperatures than it experiences in the seas around Britain and Ireland. No information has been found of the effects of very cold conditions but, since the species is not immersed for a significant length of time, adverse effects are not expected directly. Sub-optimal temperatures may delay or slow reproduction so an intolerance of low is suggested.

Increase in turbidity

1. A short-term, acute change; e.g., two categories of the water clarity scale (see glossary) for one month, such as from medium to extreme turbidity.
2. A long-term, chronic change; e.g., one category of the water clarity scale (see glossary) for one year, such as from low to medium turbidity. Further details

Evidence

Hily et al. (1992) found that, in conditions of high turbidity, Ceramium virgatum (as C. rubrum) (and Ulva sp.) dominated sediments in the Bay of Brest, France. It is most likely that Ceramium thrived because other species of algae could not. Whilst the field observations in the Bay of Brest suggests that an increase in abundance of Ceramium virgatum might be expected in conditions of increased turbidity, populations where light becomes limiting will be adversely affected. In shallow depths, Ceramium virgatum may benefit from increased turbidity whilst, near its lower depth limit, it may decline. The available information is therefore equivocal. In the absence of an intolerance assessment of 'equivocal', 'tolerant' is suggested, albeit with a very low confidence.

Decrease in turbidity

1. A short-term, acute change; e.g., two categories of the water clarity scale (see glossary) for one month, such as from medium to extreme turbidity.
2. A long-term, chronic change; e.g., one category of the water clarity scale (see glossary) for one year, such as from low to medium turbidity. Further details

Evidence

A decrease in turbidity would result in greater light availability for Ceramium virgatum and potentially potential benefit from the factor. However, the work of Hily et al. (1992) suggests that other species might out-compete Ceramium virgatum as nodulosum in lower turbidity situations. In the absence of an intolerance assessment of 'equivocal', 'tolerant' is suggested, albeit with a very low confidence.

Increase in wave exposure

A change of two ranks on the wave exposure scale (view glossary) e.g., from Exposed to Extremely exposed for a period of one year. Further details

Evidence

Ceramium virgatum occurs in extremely wave sheltered conditions (for instance, it is characteristic in the biotope 'Laminaria saccharina and Laminaria digitata on sheltered sublittoral fringe rock - SIR.Lsac.Ldig' (Connor et al. 1997a) and is recorded in some of the most sheltered parts of Hardangerfjord in Norway (Jorde & Klavestad, 1963). Strong wave action is likely to cause some damage to fronds resulting in reduced photosynthesis and compromised growth. Furthermore, individuals may be damaged or dislodged by scouring from sand and gravel mobilized by increased wave action (Hiscock, 1983). Mortality of at least a part of the population is likely due to increased wave exposure and so intolerance is assessed as intermediate. Recovery is expected to be very high: see additional information below.

Decrease in wave exposure

A change of two ranks on the wave exposure scale (view glossary) e.g., from Exposed to Extremely exposed for a period of one year. Further details

Evidence

Ceramium virgatum occurs in extremely wave sheltered conditions (for instance, it is characteristic in the biotope 'Laminaria saccharina and Laminaria digitata on sheltered sublittoral fringe rock - SIR.Lsac.Ldig' (Connor et al. 1997a) and is recorded in some of the most sheltered parts of Hardangerfjord in Norway (Jorde & Klavestad, 1963). Decrease in wave exposure is therefore unlikely to be an adverse factor.

Noise

1. Underwater noise levels e.g., the regular passing of a 30-metre trawler at 100 metres or a working cutter-suction transfer dredge at 100 metres for one month during important feeding or breeding periods.
2. Atmospheric noise levels e.g., the regular passing of a Boeing 737 passenger jet 300 metres overhead for one month during important feeding or breeding periods. Further details

Evidence

Algae have no mechanisms for detection of sound and, therefore, would be not sensitive to disturbance by noise.

Visual presence

Benchmark. The continuous presence for one month of moving objects not naturally found in the marine environment (e.g., boats, machinery, and humans) within the visual envelope of the species or community under consideration. Further details

Evidence

Algae have no visual acuity and, therefore, would not be affected by visual disturbance.

Abrasion & physical disturbance

Benchmark. Force equivalent to a standard scallop dredge landing on or being dragged across the organism. A single event is assumed for assessment. This factor includes mechanical interference, crushing, physical blows against, or rubbing and erosion of the organism or habitat of interest. Where trampling is relevant, the evidence and trampling intensity will be reported in the rationale. Further details.

Evidence

Filamentous algae generally have delicate thalli (F. Rindi, pers. comm.) and can therefore be expected to be sensitive to abrasion. In addition, the fronds appear loosely attached and would not be expected to be resistant to physical impacts. Furthermore, individuals may be damaged or dislodged by scouring from sand and gravel mobilized by increased wave action (Hiscock, 1983) and abrasion at the level set in the benchmark is likely to have a similar effect. Physical abrasion would therefore probably result in destruction of at least erect parts of the plant and loss of some whole plants. Intolerance is assessed as high. For recoverability, see additional information below.

Displacement

Benchmark. Removal of the organism from the substratum and displacement from its original position onto a suitable substratum. A single event is assumed for assessment. Further details

Evidence

It is unlikely that the holdfast would survive removal from the substratum and be able to reattach to a new substratum. Intolerance is therefore assessed as high. Recoverability is recorded as very high (see additional information below).

Synthetic compound contamination

Sensitivity is assessed against the available evidence for the effects of contaminants on the species (or closely related species at low confidence) or community of interest. For example:

• evidence of mass mortality of a population of the species or community of interest (either short or long term) in response to a contaminant will be ranked as high sensitivity;
• evidence of reduced abundance, or extent of a population of the species or community of interest (either short or long term) in response to a contaminant will be ranked as intermediate sensitivity;
• evidence of sub-lethal effects or reduced reproductive potential of a population of the species or community of interest will be assessed as low sensitivity.

The evidence used is stated in the rationale. Where the assessment can be based on a known activity then this is stated. The tolerance to contaminants of species of interest will be included in the rationale when available; together with relevant supporting material. Further details.

Evidence

Ceramium virgatum seems to be intolerant of at least some synthetic chemicals. In studies of the effect of chromated copper arsenate wood preservative, Brown et al. (2001) found that a significantly higher coverage of Ceramium nodulosum occurred on untreated wood after four weeks. Hardy (1993, cited in Holt et al., 1995) observed that Ceramium nodulosum (as Ceramium rubrum) was lost between 1923 and 1991 from the mouth of the (polluted) Tees Estuary. Inferences may also be drawn from the sensitivities of red algal species generally. O'Brien & Dixon (1976) suggested that red algae were the most sensitive group of algae to oil or dispersant contamination, possibly due to the susceptibility of phycoerythrins to destruction. They also report that red algae are effective indicators of detergent damage since they undergo colour changes when exposed to relatively low concentration of detergent. Smith (1968) reported that 10 ppm of the detergent BP 1002 killed the majority of specimens of Ceramium virgatum (as Ceramium rubrum) in 24hrs in toxicity tests. Laboratory studies of the effects of oil and dispersants on several red algal species concluded that they were all sensitive to oil/ dispersant mixtures, with little difference between adults, sporelings, diploid or haploid life stages (Grandy, 1984, cited in Holt et al., 1995). Cole et al. (1999) suggested that herbicides , such as simazine and atrazine were very toxic to macrophytes. The evidence suggests that in general red algae are very intolerant of synthetic chemicals. Intolerance of Ceramium virgatum is therefore recorded as high. Recoverability is recorded as very high (see additional information below).

Heavy metal contamination

Evidence

Bryan (1984) suggested that the general order for heavy metal toxicity in seaweeds is: Organic Hg > inorganic Hg > Cu > Ag > Zn > Cd > Pb. Cole et al. (1999) reported that Hg was very toxic to macrophytes. The sub-lethal effects of Hg (organic and inorganic) on the sporelings of an intertidal red algae, Plumaria elegans, were reported by Boney (1971). 100% growth inhibition was caused by 1 ppm Hg. No information was found concerning the effects of heavy metals on Ceramium nodulosum specifically, and therefore an intolerance assessment has not been attempted.

Hydrocarbon contamination

Evidence

Smith (1968) records that Ceramium virgatum (as Ceramium rubrum) was killed during the Torrey Canyon oil spill. O'Brien & Dixon (1976) suggested that red algae were the most sensitive group of algae to oil or dispersant contamination, possibly due to the susceptibility of phycoerythrins to destruction. Laboratory studies of the effects of oil and dispersants on several red algal species concluded that they were all sensitive to oil/ dispersant mixtures, with little difference between adults, sporelings, diploid or haploid life stages (Grandy, 1984, cited in Holt et al., 1995). Recoverability is recorded as very high (see additional information below).

Radionuclide contamination

Evidence

No evidence was found concerning the intolerance of Ceramium nodulosum to radionuclide contamination.

Changes in nutrient levels

Evidence

Hily et al. (1992) found that, in conditions of high nutrients, Ceramium virgatum (as Ceramium rubrum) (and Ulva sp.) dominated sediments in the Bay of Brest, France. Ceramium spp. are also mentioned by Holt et al. (1995) as likely to smother other species of macroalgae in nutrient enriched waters. Fletcher (1995) cites Johnston (1971/72) as associating Ceramium nodulosum (as Ceramium rubrum) with eutrophicated waters. It therefore seems that populations of Ceramium virgatum are likely to benefit from nutrification.

Increase in salinity

1. A short-term, acute change; e.g., a change of two categories from the MNCR salinity scale for one week (view glossary) such as from full to reduced.
2. A long-term, chronic change; e.g., a change of one category from the MNCR salinity scale for one year (view glossary) such as from reduced to low. Further details.

Evidence

Ceramium virgatum occurs in full salinity conditions. Although no information has been found on survival in hypersaline conditions, Ceramium virgatum occurs in rockpools where evaporation may occasionally lead to higher than normal salinities. However, occurrence of the species in full salinity, leads to an intolerance assessment of not relevant.

Decrease in salinity

1. A short-term, acute change; e.g., a change of two categories from the MNCR salinity scale for one week (view glossary) such as from full to reduced.
2. A long-term, chronic change; e.g., a change of one category from the MNCR salinity scale for one year (view glossary) such as from reduced to low. Further details.

Evidence

Ceramium virgatum occurs over a very wide range of salinities. The species penetrates almost to the innermost part of Hardanger Fjord in Norway where it experiences very low salinity values and large salinity fluctuations due to the influence of snowmelt in spring (Jorde & Klavestad, 1963). It is likely therefore that the benchmark decrease in salinity would not result in mortality, but photosynthesis would not be optimal and so growth and reproduction may be compromised. Intolerance is therefore assessed as low. Physiological processes should quickly return to normal when salinity returns to original levels, so recoverability is recorded as very high.

Changes in oxygenation

Benchmark.  Exposure to a dissolved oxygen concentration of 2 mg/l for one week. Further details.

Evidence

The effects of reduced oxygenation on algae are not well studied. Plants require oxygen for respiration, but this may be provided by production of oxygen during periods of photosynthesis. Lack of oxygen may impair both respiration and photosynthesis (see review by Vidaver, 1972). A study of the effects of anoxia on another red alga, Delesseria sanguinea, revealed that specimens died after 24 hours at 15°C but that some survived at 5°C (Hammer, 1972). Insufficient
information is available to make an intolerance assessment for Ceramium virgatum.

Introduction of microbial pathogens/parasites

Benchmark. Sensitivity can only be assessed relative to a known, named disease, likely to cause partial loss of a species population or community. Further details.

Evidence

No information has been found.

Introduction of non-native species

Sensitivity assessed against the likely effect of the introduction of alien or non-native species in Britain or Ireland. Further details.

Evidence

The habitat preferences of the gametangial phase of the non-native species Asparagopsis armata and of Ceramium virgatum are likely to overlap and Asparagopsis armata may displace some of the population of Ceramium virgatum. However, no evidence has been found to confrim displacement. In contrast, F. Rindi (pers. comm.) has noted that Ceramium virgatum is frequently epiphytic on Codium fragile subsp. Tomentosoides and therefore it can be facilitated rather than inhibited by this introduced species. Accordingly, tolerant* has been recorded but with low evidence.

Extraction of this species

Benchmark. Extraction removes 50% of the species or community from the area under consideration. Sensitivity will be assessed as 'intermediate'. The habitat remains intact or recovers rapidly. Any effects of the extraction process on the habitat itself are addressed under other factors, e.g. displacement, abrasion and physical disturbance, and substratum loss. Further details.

Evidence

There is no extraction of Ceramium virgatum known to occur.

Extraction of other species

Benchmark. A species that is a required host or prey for the species under consideration (and assuming that no alternative host exists) or a keystone species in a biotope is removed. Any effects of the extraction process on the habitat itself are addressed under other factors, e.g. displacement, abrasion and physical disturbance, and substratum loss. Further details.

Evidence

No species are known to be extracted that might lead to loss of Ceramium virgatum.