• Quantitative analysis of azaspiracids in Azadinium spinosum cultures

      Jauffrais, Thierry; Herrenknecht, Christine; Séchet, Véronique; Sibat, Manoella; Tillmann, Urban; Krock, Bernd; Kilcoyne, Jane; Miles, Christopher O.; McCarron, Pearse; Amzil, Zouher; Hess, Philipp (Springer, 2012)
      Azaspiracids (AZAs) are secondary metabolites of Azadinium spinosum that can accumulate in shellfish and cause food poisoning when consumed. We describe here an analytical procedure for the determination of AZAs in cultures of A. spinosum with a focus on the formation of AZA methyl esters as artefacts during extraction and sample pre-treatment. A. spinosum cells were collected from bioreactor cultures using centrifugation or filtration. Different extraction procedures were evaluated for formation of methyl ester artefacts, yield, and matrix effects. Filtration of cultures using glass-fibre filters led to increased formation of methyl esters, and centrifugation is recommended for recovery of cells. The extraction solvent (methanol (MeOH), acetone, and acetonitrile (MeCN)) did not significantly affect the yield of AZAs as long as the organic content was 80% or higher. However, the use of MeOH as extraction solvent led to increased formation of methyl esters. AZA1 recovery over two successive extractions was 100% at the 95% confidence level for acetone and MeOH. In standard-addition experiments, no significant matrix effects were observed in extracts of A. spinosum or Azadinium obesum up to a sample size of 4.5 × 109 μm3. Moreover, experiments carried out to clarify the formation and structure of methylated AZA analogues led to the description of two AZA methyl esters and to the correction of the chemical structures of AZAs29–32.
    • Rapid and highly variable warming of lake surface waters around the globe

      O'Reilly, C.M.; Sharma, S.; Gray, D.K.; Hampton, S.E.; Read, J.S.; Rowley, R.J.; Schneider, P.; Lenters, J.D.; McIntyre, P.B.; Kraemer, B.J.; Wayhenmeyer, G.A; Straile, D.; Dong, B.; Adrian, R.; Allan, M.G.; Anneville, O.; Arvola, L.; Austin, J.; Bailey, J.L.; Baron, J.S.; Brookes, J.D.; de Eyto, E.; Dokulil, M.T.; Hamilton, D.T.; Havens, K.; Hetherington, A.L.; Higgins, S.N.; Hook, S.; Izmest'eva, L.R.; Joehnk, K.D.; Kangur, K.; Kasprzak, P.; Kumagai, M.; Kuusisto, E.; Leshkevich, G.; Livingstone, D.M.; MacIntyre, S.; May, L.; Melack, J.M.; Mueller-Navarra, D.C.; Naumenko, M; Noges, P.; Noges, T.; North, R.P.; Plisnier, P.D.; Rigosi, A.; Rimmer, A.; Rogora, M.; Rudstam, L.G.; Rusak, J.A.; Salmaso, N.; Samal, N.R.; Schindler, D.E.; Schladow, S.G.; Schmid, M.; Schmidt, S.R.; Silow, E.; Soylu, M.E.; Teubner, K.; Verburg, P.; Voutilainen, A.; Watkinson, A.; Williamson, C.E.; Zhang, G. (American Geophysical Union, 2015)
      In this first worldwide synthesis of in situ and satellite-derived lake data, we find that lake summer surface water temperatures rose rapidly (global mean = 0.34°C decade 1) between 1985 and 2009. Our analyses show that surface water warming rates are dependent on combinations of climate and local characteristics, rather than just lake location, leading to the counterintuitive result that regional consistency in lake warming is the exception, rather than the rule. The most rapidly warming lakes are widely geographically distributed, and their warming is associated with interactions among different climatic factors —from seasonally ice-covered lakes in areas where temperature and solar radiation are increasing while cloud cover is diminishing (0.72°C decade 1) to ice-free lakes experiencing increases in air temperature and solar radiation (0.53°C decade 1). The pervasive and rapid warming observed here signals the urgent need to incorporate climate impacts into vulnerability assessments and adaptation efforts for lakes.
    • Recent data suggest no further recovery in North Sea Large Fish Indicator

      Fung, Tak; Farnsworth, Keith D.; Reid, David G.; Rossberg, Axel G. (Oxford Journals, 2012)
      We detail the calculations of North Sea Large Fish Indicator values for 2009–2011, demonstrating an apparent stall in recovery. Therefore, recovery to the Marine Strategy Framework Directive's good environmental status of 0.3 by the 2020 deadline now looks less certain and may take longer than was expected using data from 2006 to 2008.
    • The recent population expansion of boarfish, Capros aper (Linnaeus, 1758): interactions of climate, growth and recruitment

      Coad, J.O.; Hüssy, K.; Farrell, E.D.; Clarke, M.W. (John Wiley & Sons, Inc, 2014)
      The objectives of this study were to evaluate whether temperature changes in the Northeast Atlantic influence the growth and recruitment dynamics of boarfish, Capros aper. Two geographically separate areas were examined, ‘north’ at the northern distribution range west of Ireland and ‘south’ on the main fishing grounds south of Ireland. No significant differences in length-at-age were observed between the two areas. Interannual otolith growth patterns were similar between the two areas with distinct years of faster and slower growth. In the ‘north’, no significant relationship between adult growth and temperature was observed, while growth in the ‘south’ was positively related to temperature up to approximately 16°C growth rates were suppressed in the years with temperatures above that. Recruitment showed a positive correlation with adult growth the previous year for the Spanish recruitment index only, suggesting spatial connectivity between the Celtic Sea and the Bay of Biscay. The age distributions were similar in both areas and despite the boarfish's longevity of >30 years, are dominated by the age classes corresponding to the years with high recruitment, suggesting that increased recruitment is responsible for the observed stock expansion.
    • Report of the Study Group on Nephrops Surveys (SGNEPS)

      Doyle, J.; Lordan, C. (International Council for the Exploration of the Sea (ICES), 2013)
      The Study Group on Nephrops Surveys (SGNEPS) met in Ancona, Italy from 6–8 March 2012. The group consisted of 12 scientists from Ireland, Scotland, England, Northern Ireland, Spain, Denmark, Portugal and Italy under the chairmanship of Colm Lordan, Ireland. SGNEPS has an important role as the international coordina-tion group for Nephrops UWTV surveys in the North Atlantic and Mediterranean. Heretofore SGNEPS has focused on planning, protocols, quality control, design and survey development issues. At the 2012 meeting group compiled a table summarizing the station densities and precision levels of most annual Nephrops UWTV surveys. Large variations in survey station densities occur across the grounds currently sur-veyed. Station density, accuracy and precision trade-offs were investigated and dis-cussed in detail for the two main survey design types (random stratifies and grids). The main outcome of these deliberation was that a minimum precision level of <20% CV (also known as Relative Standard Error) should be attained for these types of surveys. There may be operational reasons why individual surveys should aim for higher precision than that (e.g. to ensure good coverage and accurate burrow surfac-es). In some areas station densities could be reduce to allow for improved coverage to previously unsurveyed Nephrops grounds. Progress towards integrated stock assess-ments for Nephrops which make use of all sources of fisheries dependent and inde-pendent information was reported to the group. There was consensus that the current ICES framework for assessing and providing catch options based on the UWTV sur-veys remains the most appropriate methodology for the moment. There has been significant progress since WKNEPH (ICES, 2007) in addressing many of the per-ceived uncertainties in the methodology. The remaining assumptions on burrow occupancy, burrow size, growth, discard survival can only be addressed through dedicated research projects of which there have been few. Several video enhancement and technological developments were presented to the group and these look very promising in terms of improving certainty of burrow identification and facilitating validation counts. The group also discussed the various Nephrops trawl surveys and biological sampling requirements under the DCF and concluded that the role of the group should be expanded to cover these in future.
    • Reproductive biology of the starry smooth-hound shark (Mustelus asterias): geographic variation and implications for sustainable exploitation

      Farrell, E D; Mariani, S; Clarke, M W (Wiley-Blackwell, 2010)
      Examination of the reproductive biology of Mustelus asterias in the north-east Atlantic Ocean highlighted apparent geographical variation in maturity, fecundity and ovarian cycle between Atlantic and Mediterranean populations. The stretch total length (LST) and age at 50% maturity for Atlantic males and females were estimated at 78 cm LST and 4–5 years and 87 cm LST and 6 years, respectively. Size at maturity of females was considerably smaller than in Mediterranean specimens (96 cm LST). Ovarian fecundity ranged from eight to 27 oocytes and uterine fecundity from six to 18 embryos. The gestation period was c. 12 months, followed by a resting period of c. 12 months, resulting in a biennial cycle. Females stored sperm in the oviducal gland and, unlike Mediterranean specimens, no uterine compartments were observed in Atlantic specimens. This study reveals the existence of strong, possibly adaptive, divergence in life-history traits in an elasmobranch, whose northern populations may be more susceptible to overexploitation than previously believed.
    • The response of North Atlantic diadromous fish to multiple stressors including land use change: a multidecadal study

      de Eyto, E.; Dalton, C.; Dillane, M.; Jennings, E.; McGinnity, P.; O'Dwyer, B.; Poole, R.; Rogan, G.; Taylor, D. (NRC Research Press, 2016)
      Reduction of freshwater habitat quality due to land use change can have significant impacts on diadromous fish. Partitioning this impact from other potential drivers, such as changing marine conditions and climate, is hampered by a lack of long term datasets. Here, four decades of data were used to assess the impact of land use change on <i>Salmo salar</i> L. and anadromous <i>Salmo trutta</i> L. in the Burrishoole catchment, Ireland, one of the few index sites for diadromous fish in the North Atlantic. Land use change was found to have no significant impact on the freshwater survival of either salmon or trout. However, climate impacted significantly on the survival of salmon and trout in freshwater, with poor survival in years with wetter warmer winters, coinciding with positive North Atlantic Oscillation values. Additionally, cold springs were associated with higher survival in trout. The addition of hatchery salmon into the salmon spawning cohort coincided with low freshwater survival. Our results highlight the necessity for a broad ecosystem approach in any conservation effort of these species.
    • The rise and fall of autumn-spawning herring (Clupea harengus L.) in the Celtic Sea between 1959 and 2009: Temporal trends in spawning component diversity

      Harma, Clémentine; Brophy, Deirdre; Minto, Cóilín; Clarke, Maurice (Elsevier, 2012)
      Sub-stock components of highly exploited migratory fish species exhibit different life-history traits and can thus show variation in productivity and vulnerability to fishing pressure. Celtic Sea herring comprises both autumn and winter-spawners that are targeted by the same fishery. The current study investigated if the relative abundances of the two components in the Celtic Sea have changed over time, and whether this could explain marked long-term trends in size-at-age. The study utilized a remarkably long time-series of biological data from commercial landings (1959–2009). Based on the maturity state of the gonads at the time of sampling, herring were assigned to seasonal spawning components. Significant temporal variations in spawning component dominance were found, even after potential bias due to fishing history patterns were accounted for. Strong directional changes in the relative proportion of spawning components consisted of autumn spawning herring proportions reaching a peak in the 1990s before drastically declining. Winter spawning herring had lower mean lengths- and weights-at-age than autumn spawning herring. The recent decline in the autumn spawning component did not fully explain the observed decline in size-at-age in the catches, with both spawning components showing similar decreases in mean-size parameters over time. Response of spawning components to environmental changes may have consequences for the fishery, especially in light of the observed influence of temperature on spawning components. Life-cycle diversity in herring stocks may confer resilience to potential climate-induced changes. Therefore, it is suggested that the relative proportions of spawning components should be monitored and diversity should be preserved as part of the management of fisheries for this species, which is characterized by stock complexity.
    • Screen for Footprints of Selection during Domestication/Captive Breeding of Atlantic Salmon

      Vasemägi, Anti; Nilsson, Jan; McGinnity, Philip; Cross, Tom; O'Reilly, Patrick; Glebe, Brian; Peng, Bo; Berg, Paul Ragnar; Primmer, Craig Robert (Hindawi Publishing Corporation, 2012)
      Domesticated animals provide a unique opportunity to identify genomic targets of artificial selection to the captive environment. Here, we screened three independent domesticated/captive Atlantic salmon (Salmo salar) strains and their wild progenitor populations in an effort to detect potential signals of domestication selection by typing of 261 SNPs and 70 microsatellite loci. By combining information from four different neutrality tests, in total ten genomic regions showed signs of directional selection based on multiple sources of evidence. Most of the identified candidate regions were rather small ranging from zero to a few centimorgans (cM) in the female Atlantic salmon linkage map. We also evaluated how adaptation from standing variation affects adjacent SNP and microsatellite variation along the chromosomes and, by using forward simulations with strong selection, we were able to generate genetic differentiation patterns comparable to the observed data. This study highlights the significance of standing genetic variation during the early stages of adaptation and represents a useful step towards identifying functional variants involved in domestication of Atlantic salmon.
    • Seabird movement reveals the ecological footprint of fishing vessels

      Bodey, T.W.; Jessopp, M.J.; Votier, S.C.; Gerritsen, H.D.; Cleasby, I.R.; Hamer, K.C.; Patrick, S.C.; Wakefield, E.D.; Bearhop, S. (Cell Press, 2014)
      Exploitation of the seas is currently unsustainable, with increasing demand for marine resources placing intense pressure on the Earth’s largest ecosystem [1]. The scale of anthropogenic effects varies from local to entire ocean basins 1, 2 and 3. For example, discards of commercial capture fisheries can have both positive and negative impacts on scavengers at the population and community-level 2, 3, 4, 5 and 6, although this is driven by individual foraging behaviour 3 and 7. Currently, we have little understanding of the scale at which individual animals initiate such behaviours. We use the known interaction between fisheries and a wide-ranging seabird, the Northern gannet Morus bassanus [3], to investigate how fishing vessels affect individual birds’ behaviours in near real-time. We document the footprint of fishing vessels’ (≥15 m length) influence on foraging decisions (≤11 km), and a potential underlying behavioural mechanism, by revealing how birds respond differently to vessels depending on gear type and activity. Such influences have important implications for fisheries, including the proposed discard ban [8]), and wider marine management.
    • Significant differences in the length–weight relationships of neighbouring stocks can result in biased biomass estimates: examples of haddock (Melanogrammus aeglefinus, L.) and whiting (Merlangius merlangus, L.)

      McGrath, D; Gerritsen, H.D. (Elsevier, 2007)
      Length–weight relationships of fish are often used to estimate the biomass of length distributions or to obtain indices of condition. Although large-scale spatial trends are known to exist, it is often assumed that length–weight relationships do not vary significantly within stocks or between neighbouring stocks. The present study examined length–weight relationships of 1334 haddock (Melanogrammus aeglefinus) and 1186 whiting (Merlangius merlangus) collected on a groundfish survey in the waters around Ireland in 2004. Additionally, condition indices were estimated for individual fish and for length frequency samples. The length–weight regression showed a significant area effect and no differences between the sexes. The condition indices showed a moderate spatial structure for both species: around 25% of the variability could be explained by the location of the samples, the rest of the variability was due to other sources. Length–weight relationships did not appear to vary significantly within stocks, however differences between stocks were significant. In the present case, a bias of up to 10% could occur in biomass estimates as a result of applying length–weight relationships of one stock to length data of a neighbouring stock.
    • A simple method for comparing age–length keys reveals significant regional differences within a single stock of haddock (Melanogrammus aeglefinus)

      McGrath, D; Lordan, C; Gerritsen, H.D. (Oxford University Press, 2006)
      A multinomial logistic model is presented as a tool for comparing two or more age–length keys. The model provides an objective way to fill in missing values and can be used for estimating uncertainty and visualizing age–length keys (ALKs). An example of haddock (Melanogrammus aeglefinus L.) in ICES Division VIa (West of Scotland) is used to illustrate that significant regional differences in the proportions of age classes-at-length can exist on a small spatial scale. These differences are caused by regional variation in both length-at-age and relative abundance at age. As the length-at-age data are normally not weighted by the local catch rate (abundance), the ALK of the combined age data can result in strongly biased estimates of numbers-at-age. In the present case, the use of unweighted age data would have resulted in an overestimate of recruitment of nearly 200% and an underestimate of spawning stock biomass of 15%. Comparing ALKs using this method has several practical applications in fisheries science.
    • Size-selective fishing drives species composition in the Celtic Sea

      Shephard, Samuel; Fung, Tak; Houle, Jennifer E.; Farnsworth, Keith D.; Reid, David G.; Rossberg, Axel G. (Oxford Journals, 2012)
      Fishing alters community size structure by selectively removing larger individual fish and by changing the relative abundance of different-sized species. To assess the relative importance of individual- and species-level effects, two indices of fish community structure were compared, the relative abundance of large fish individuals (large fish indicator, LFI) and the relative abundance of large fish species (large species indicator, LSI). The two indices were strongly correlated for empirical data from the Celtic Sea and for data from simulated model communities, suggesting that much of the variability in the LFI is caused by shifts in the relative abundance of species (LSI). This correlation is explained by the observation that most of the biomass of a given species is spread over few length classes, a range spanning the factor 2 of individual length, such that most species contributed predominantly to either the small or the large component of the LFI. The results suggest that the effects of size-selective fishing in the Celtic Sea are mediated mainly through changes in community composition.
    • Spatial and seasonal variation of peatland-fed riverine macroinvertebrate and benthic diatom assemblages and implications for assessment: a case study from Ireland

      O’Driscoll, C.; de Eyto, E.; Rodgers, M.; O’Connor, M.; Asam, Z-u-Z; Kelly, M.; Xiao, L. (Springer, 2014)
      Blanket peat catchments are important biodiversity refugia. Key pressures on peatland catchment water bodies include artificial drainage, forestry, over-grazing, wind farm development and climate change, and assessment of these pressures requires sensitive monitoring programmes. This study, undertaken in two neighbouring blanket peat catchments, examined the variability in macroinvertebrate and diatom assemblages and related indices in response to spatial and seasonal variability. Multivariate analysis revealed significant trends in the taxa distribution of both groups and the indices downstream and away from the constraining influence of the peat. However, the ecological quality ratios and status assessments for the associated water bodies were consistent irrespective of spatial variability in assemblages and raw indices. Significant seasonal trends emerged only in the macroinvertebrate assemblages and indices. This study contributes to the understanding of sources of uncertainty in ecological assessment and thus provides valuable information for the calibration of assessment protocols for sensitive peatland catchments.
    • Spatial Heterogeneity in Fishing Creates de facto Refugia for Endangered Celtic Sea Elasmobranchs

      Shephard, Samuel; Gerritsen, H.D.; Kaiser, Michel J.; Reid, David G. (PLOS, 2012)
      The life history characteristics of some elasmobranchs make them particularly vulnerable to fishing mortality; about a third of all species are listed by the IUCN as Threatened or Near Threatened. Marine Protected Areas (MPAs) have been suggested as a tool for conservation of elasmobranchs, but they are likely to be effective only if such populations respond to fishing impacts at spatial-scales corresponding to MPA size. Using the example of the Celtic Sea, we modelled elasmobranch biomass (kg h21) in fisheries-independent survey hauls as a function of environmental variables and ‘local’ (within 20 km radius) fishing effort (h y21) recorded from Vessel Monitoring Systems data. Model selection using AIC suggested strongest support for linear mixed effects models in which the variables (i) fishing effort, (ii) geographic location and (iii) demersal fish assemblage had approximately equal importance in explaining elasmobranch biomass. In the eastern Celtic Sea, sampling sites that occurred in the lowest 10% of the observed fishing effort range recorded 10 species of elasmobranch including the critically endangered Dipturus spp. The most intensely fished 10% of sites had only three elasmobranch species, with two IUCN listed as Least Concern. Our results suggest that stable spatial heterogeneity in fishing effort creates de facto refugia for elasmobranchs in the Celtic Sea. However, changes in the present fisheries management regime could impair the refuge effect by changing fisher’s behaviour and displacing effort into these areas.
    • Spatial patterns in the retained catch composition of Irish demersal otter trawlers: high-resolution fisheries data as a management tool

      Gerritsen, H.D.; Lordan, C.; Minto, C.; Kraak, S.B.M. (Elsevier, 2012)
      High-resolution fisheries data from integrated logbook and Vessel Monitoring Systems (VMS) records have revealed a detailed spatial structure in the species composition of the retained catches of the Irish demersal otter trawl fleets. Hierarchical cluster analysis was used to define 8 clusters with relatively homogenous species compositions. These clusters formed 34 distinct spatial regions in the waters around Ireland. Identification of these regions can be useful for a number applications, including spatial stratification of commercial or survey data, defining and characterising fishing grounds for marine spatial planning, evaluation of closed areas and prediction of how fishing effort might be re-allocated following a closure. A casestudy is presented that explores options to reduce cod (Gadus morhua) catches by implementing seasonal closures in two of the 34 regions. Cod are caught by demersal trawlers in a mixed fishery and the catches often exceed the quota, resulting in discarding of marketable fish. Two regions were identified that had relatively low effort and high cod landings. The effects of closing these regions during the first quarter of the year were explored. Cod catches were likely to be reduced by 8-22% while only 3-9% of the annual demersal otter trawl effort would be displaced. Whiting catches were also likely to be reduced, the change in catches of some other species depended on the assumed effort displacement.
    • Spatial Segregation within the Spawning Migration of North Eastern Atlantic Mackerel (Scomber scombrus) as Indicated by Juvenile Growth Patterns

      Jansen, T.; Campbell, A.; Brunel, T.; Worsøe Clausen, L. (PLoS ONE, 2013)
      A comparison of growth data (fish length) with latitude shows that southern juvenile mackerel attain a greater length than those originating from further north before growth ceases during their first winter. A similar significant relationship was found between the growth in the first year (derived from the otolith inner winter ring) and latitude for adult mackerel spawning between 44uN (Bay of Biscay) and 54uN (west of Ireland). These observations are consistent with spatial segregation of the spawning migration; the further north that the fish were hatched, the further north they will tend to spawn. No such relationship was found in mackerel spawning at more northerly latitudes, possibly as a consequence of increased spatial mixing in a more energetic regime with stronger currents. This study provides previously lacking support for spawning segregation behaviour among North East Atlantic mackerel – an important step towards understanding the migratory behaviour of mackerel and hence the spatiotemporal distribution dynamics around spawning time.
    • Strategies for the elimination of matrix effects in the LC-MS/MS analysis of the lipophilic toxins okadaic acid and azaspiracid-1 in molluscan shellfish

      Kilcoyne, J; Fux, E (Elsevier, 2010)
      Considerable efforts are being made worldwide to replace in vivo assays with instrumental methods of analysis for the monitoring of marine biotoxins in shellfish. Analysis of these compounds by the preferred technique of LC-MS/MS is challenged by matrix effects associated with shellfish tissue components. In methods validation, assessment of matrix interferences is imperative to ensure the accuracy of analytical results. We evaluated matrix interferences in the analysis of okadaic acid (OA) and azaspiracid 1 (AZA1) in mollucscan shellfish by using a conventional acidic method on electrospray triple stage quadrapole (TSQ) and hybrid quadrupole time of flight (QToF) instruments, with matrix matched standards for several species. Using the acidic method, we found no matrix interferences for OA, and matrix suppression for AZA1, with the TSQ instrument; in contrast, we found matrix enhancement for OA, and no matrix interference for AZA1, with QToF. The suppression of AZA1 signal on the TSQ instrument was due to interfering compounds carried over from previous injections. The degree of suppression was dependent on the tissue type, ranging from 20 to 70%. Several strategies were evaluated to eliminate these interferences, including the partitioning of the extract with hexane, optimization of the chromatographic
    • Suspended solid yield from forest harvesting on upland blanket peat

      Rodgers, Michael; O'Connor, Mark; Robinson, Mark; Muller, Markus; Poole, Russell; Xiao, Liwen (Wiley Online Library, 2011)
      Forest harvesting activities, if not carefully carried out, can disturb the forest soils and can cause significant suspended solid concentration increases in receiving water. This study examined how harvesting, following forestry guidelines, influenced suspended solid concentrations and loads in the receiving water of a blanket peat salmonid catchment. The study site comprised of two forest coupes of 34-year-old conifers drained by a first-order stream. The upper coupe was not felled and acted as a baseline ‘control’ catchment; the downstream coupe was completely harvested in summer 2005 and served as the ‘experimental’ catchment. Good management practices such as the proper use of brash mats and harvesting only in dry weather were implemented to minimize soil surface disturbance and streambank erosion. Stream flow and suspended solid measurements at an upstream station (US) and a downstream station (DS) in the study stream commenced over a year before felling took place. The suspended solid concentrations, yields and release patterns at US and DS were compared before and after harvesting. These showed that post-guideline harvesting of upland blanket peat forest did not significantly increase the suspended solid concentrations in the receiving water and the aquatic zone need not be adversely affected by soil releases from sites without a buffer strip.
    • A test battery approach to the ecotoxicological evaluation of cadmium and copper employing a battery of marine bioassays

      Macken, A; Giltrap, M; Ryall, K; Foley, B; McGovern, E; McHugh, B; Davoren, M (Springer, 2009)
      Heavy metals are ubiquitous contaminants of the marine environment and can accumulate and persist in sediments. The toxicity of metal contaminants in sediments to organisms is dependent on the bioavailability of the metals in both the water and sediment phases and the sensitivity of the organism to the metal exposure. This study investigated the effects of two metal contaminants of concern (CdCl2 and CuCl2) on a battery of marine bioassays employed for sediment assessment. Cadmium, a known carcinogen and widespread marine pollutant, was found to be the least toxic of the two assayed metals in all in vivo tests. However CdCl2 was found to be more toxic to the fish cell lines PLHC-1 and RTG-2 than CuCl2. Tisbe battagliai was the most sensitive species to both metals and the Microtox® and cell lines were the least sensitive (cadmium was found to be three orders of magnitude less toxic to Vibrio fischeri than to T. battagliai). The sensitivity of Tetraselmis suecica to the two metals varied greatly. Marine microalgae are among the organisms that can tolerate higher levels of cadmium. This hypothesis is demonstrated in this study where it was not possible to derive an EC50 value for CdCl2 and the marine prasinophyte, T. suecica. Conversely, CuCl2 was observed to be highly toxic to the marine alga, EC50 of 1.19 mg l-1. The genotoxic effect of Cu on the marine phytoplankton was evaluated using the Comet assay. Copper concentrations ranging from 0.25 to 2.50 mg l-1 were used to evaluate the effects. DNA damage was measured as percent number of comets and normal cells. There was no significant DNA damage observed at any concentration of CuCl2 tested and no correlation with growth inhibition and genetic damage was found.