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Ocean acidification (OA), the anthropogenic carbon dioxide-induced changes in seawater carbonate chemistry, is likely to have a significant impact on calcifying plankton. Most planktonic studies on OA are based on “one-off” cruises focused on offshore areas while observations from inshore waters are scarce. This study presents the first analysis on the shell integrity of pelagic gastropods (holoplanktonic pteropods and planktonic larvae of otherwise benthic species) at the Scottish Coastal Observatory monitoring site at Stonehaven on the east coast of Scotland. The shell integrity of archived pelagic gastropods specimens from 2011 to 2013 was examined using Scanning Electron Microscopy and the relationship with OA (pH and aragonite saturation, Ωarg) and other environmental parameters was investigated. Evidence of shell dissolution was detected in all analysed taxa even though the seawater was supersaturated with respect to aragonite. The shell condition matched the temporal pattern observed in Ωarg, with higher proportion of dissolution associated with decreasing Ωarg, suggesting that the seasonality component of carbonate chemistry might affect the shell integrity of pelagic gastropods. The proportion of shell dissolution differed significantly between larvae and adult stages of pteropods, supporting the hypothesis that early-life stages would be more vulnerable to OA-induced changes. Our data also suggest that sensitivity to OA may differ even between closely related taxonomic groups. The strong interannual variability revealed by the year-to-year shell dissolution and Ωarg illustrates the difficulty in assessing the plankton response to OA in the field and the value of time series studies.

Concentrations of thirty two polychlorinated biphenyls (PCBs) were determined in the blubber of five sympatric species of odontocetes stranded or by-caught along the Northwest coast of the Iberian Peninsula: common dolphin (Delphinus delphis), long-finned pilot whale (Globicephala melas), harbour porpoise (Phocoena phocoena), striped dolphin (Stenella coeruleoalba) and bottlenose dolphin (Tursiops truncatus). Multivariate analyses were applied to evaluate the ability of PCB patterns to discriminate these sympatric species and to determine which eco-biological factors influence these patterns, thus evaluating the relevance of PCB concentrations as biogeochemical tracers of feeding ecology. The five species could be separated according to their PCB patterns. Different exposure to these contaminants, a consequence of their different dietary preferences or habitats, together with potentially dissimilar metabolic capacities, likely explain these results; sex, age, habitat and the type of prey eaten were the most important eco-biological parameters of those tested. Although, no single congener has been specifically identified as a tracer of feeding ecology, 4 congeners from the 22 analysed seemed to be the most useful and around12 congeners appear to be enough to achieve good discrimination of the cetaceans studied. Therefore, this study suggests that PCB patterns can be used as tracers for studying the feeding ecology, sources of contamination or even population structure of cetacean species from the Northwest Iberian Peninsula

Understanding the status of contaminants in the marine environment is a requirement of European Union Directives and the Regional Seas Conventions, so that measures to reduce pollution can be identified and their efficacy assessed. The international ICON workshop (Hylland et al., 2017) was developed in order to test an integrated approach to assessing both contaminant concentrations and their effects. This paper describes and assesses the concentrations of trace metals, polycyclic aromatic hydrocarbons, and polychlorinated biphenyls in sediments, mussels, and fish collected from estuarine, coastal and offshore waters from Iceland to the Mediterranean Sea. For organic contaminants, concentrations progressively increased from Iceland, to the offshore North Sea, to the coastal seas, and were highest in estuaries. Metals had a more complex distribution, reflecting local anthropogenic inputs, natural sources and hydrological conditions. Use of internationally recognised assessment criteria indicated that at no site were concentrations of all contaminants at background and that concentrations of some contaminants were of significant concern in all areas, except the central North Sea.

Concentrations of Ag, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, V and Zn were investigated in the liver and kidney of the five most common toothed whales off the Northwest Iberian Peninsula (NWIP), specifically common dolphin, long-finned pilot whale, harbour porpoise, striped dolphin and bottlenose dolphin. Differences were observed in the bioaccumulation of the above elements between the five species. The differences are probably related to biological factors such as age and sex and/or to ecological factors specific to each species such as feeding habits or bioavailability of the various elements. However, no significant relationship was observed between element accumulation and sex. Pilot whale and striped dolphin showed the highest concentrations of renal Cd and the highest concentrations of hepatic Hg and Se, while bottlenose dolphin showed the highest concentrations of Hg in kidneys. An analysis of inter-elemental relationships showed strong positive correlations between Hg and Se in the five species, however most individuals have Hg:Se molar ratio less than 1:1 indicating an excess of Se compare to Hg. This result, probably reflect the high proportion of young animals in the sample available for this study and/or that these animals had a good health status. We also observed a positive correlation in striped dolphins between Cd and Cu and between Cd and Zn in kidneys. In addition, comparing with other studies world-wide, the element concentrations (Hg and Cd) found in Iberian toothed whales indicate that these populations are not specially threatened by Hg and Cd exposure in the area.

Coryphaenoides armatus is a cosmopolitan deep-sea fish that plays a major role in the ecology of abyssal ecosystems. We investigated the trophic ecology and physiology of this species by determining the δ13C, δ15N and fatty acid signatures of muscle, liver and ovary tissues of individuals collected from ∼2700 m to the north and south of the Charlie-Gibbs Fracture Zone (CGFZ) of the Mid-Atlantic Ridge, NE Atlantic. Fatty acid and δ13C data both suggested that C. armatus shows an ontogenetic dietary shift, with the relative contributions of benthic and pelagic prey decreasing and increasing respectively as the animals grow. They also indicated that dietary overlap between animals living to the north and south of the CGFZ increases as they grow, suggesting that larger animals forage over greater distances and are not hindered by the presence of the CGFZ. Comparison of tissue-specific fatty acid signatures with previously published data suggests compositional homeostasis of the fatty acids 20:5(n−3) and 22:6(n−3) in the muscle, and 18:1(n−9) in the liver tissues. We ascribe this primarily to strict physiological requirements for these compounds, rather than simply to their abundance in the diet. We pose several speculative mechanisms to explain the observed trends in tissue-specific δ13C and δ15N values, illustrating some of the numerous processes that can influence the isotopic signatures of bulk tissues.

Polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) are environmental contaminants regulated by the Stockholm Convention of Persistent Organic Pollutants. Being hydrophobic and lipophilic, these compounds accumulate in the marine environment in sediments and lipid-rich tissue of marine organisms, making these matrices preferred media for environmental monitoring. This document focuses on the analysis of PCDD/Fs and dioxin-like PCBs (i.e. non-ortho and mono-ortho PCBs), which have a similar planar molecular structure to PCDD/Fs, and therefore, exhibit similar toxic effects. As concentrations in the environment are low and common analytical methods lead to co-extractions of a large variety of potentially interfering compounds, analytical procedures are complex. The present document includes comments and advice on sampling and sample pre-treatment steps, suitable extraction and clean-up procedures as well as pre-concentration methods and highlights the importance of extract clean-up and the risk of contamination. Furthermore, suitable methods for instrumental analysis are discussed, in terms of gas chromatographic separation, compound identification and quantification and detection methods. Although high resolution mass spectrometry often is the method of choice, low resolution mass spectrometry can also provide sufficiently sensitive analyses, in particular for screening purposes. In this context, bioassays can also play a role, which reflect a cumulative toxicity rather than concentrations of individual congeners. The paper also discusses general aspects of good laboratory practice, quality assurance/quality control and laboratory safety.