Organochlorine Pesticides and Polychlorinated Biphenyls in the Subcutaneous Adipose Tissue of Beluga Whales (Delphinapterus leucas) of the White,Kara and Bering Seas

Oceanology - The OCP and PCB contents in the tissues of beluga whales (Delphinapterus leucas) from the Russian Arctic have been studied for the first time. Skin and subcutaneous adipose tissue...     

Intra- and inter-species differences in persistent organic contaminants in the blubber of blue whales and humpback whales from the Gulf of St. Lawrence, Canada

Biopsy samples of blubber from adult male and female blue whales, and from female and young-of-the-year humpback whales were collected during the summers of 1992-1999 in the Gulf of St. Lawrence, Canada. In blue whales, concentrations of 25 PCB congeners, DDT and metabolites and several other organochlorine compounds were present at higher concentrations in the blubber of males relative to females; reflecting maternal transfer of these persistent contaminants from females into young. Sex-related differences in concentrations were not observed with less persistent contaminants, such as HCHs. In humpback whale samples, there were no significant differences in the concentrations of PCBs and organochlorine compounds in the blubber of females and calves. These data indicate that calves quickly bioaccumulate contaminants by transplacental and lactational routes to concentrations that are in equilibrium with females. In comparisons between contaminant concentrations and patterns in the blubber of female blue and humpback whales, there were no significant differences in concentrations, but the proportions of some PCB congeners, HCH isomers, and DDT and its metabolites were different in the two baleen whale species. These may reflect differences in the diet of the two species, since fish comprise a large part of the diet of humpback whales and blue whales feed exclusively on euphausiid crustaceans (i.e. krill).     

Profiles of dissolved and acid-leachable selenium in a sediment core from the lower St. Lawrence estuary

Concentrations of Se in the pore-water and in the solid phase, and the concentrations of other diagenetic constituents (Fe, Mn, phosphate, ammonium and I) in pore-water, were determined in a sediment core from a 350-m deep station in the lower St. Lawrence Estuary. The concentration of dissolved Se in pore-water was 2.1 nmol kg⁻¹ at the surface of the core, increasing to a maximum of 7.6 nmol kg⁻¹ at a depth of 12 cm, and thereafter decreasing gradually with depth. This profile is similar to the profiles of Fe and phosphate, whose concentration maxima occur around 10 cm. The concentration of total sedimentary Se remained almost constant with depth (≈ 0.75 mg kg⁻¹); however, a significant enrichment of oxalate-leachable Se was observed in the top 2 cm. The sedimentary cycling of Se appears to be closely related to that of Fe: adsorption of Se onto Fe oxyhydroxide at or near the sediment-water interface, release of the adsorbed Se by the reduction of Fe oxyhydroxide, and removal by formation of ferroselite (FeSe₂) at depth. The pore-water flux of Se was estimated by two different methods, firstly from the pore-water gradient, and secondly by applying a box model to the oxalate-leachable solid-phase Se data. The methods agree well both giving values for the flux of 0.11 nmol cm⁻² year⁻¹. This agreement suggests that the loss of labile Se in the sediment is balanced by the upward flux of dissolved Se.     

Suspended particulate matter in the St. Lawrence estuary and Gulf surface layer and development of a remote sensing algorithm

Remote sensing of chlorophyll concentration is potentially affected by the presence of inorganic matter in the water column. Seasonal variability of total suspended particulate matter (SPM) concentration and its partition into organic and inorganic fractions was thus measured in the estuary and Gulf of St. Lawrence during five cruises. These measures were made in the surface layer down to the depth of the 0.1% light level. Results indicate that vertical variability was small for the entire study area. Data analysis lead to the definition of two main regions having different SPM characteristics: 1) the estuary zone characterized by a strong spatial variability, intermediate SPM concentrations and a clear spring phytoplankton bloom that is combined to an increased inorganic matter load; 2) the gulf region characterized by a relatively low SPM concentration and phytoplankton blooms in the spring and fall periods. Combined with in situ measurements of remote sensing reflectances, the database was used to validate existing inorganic matter retrieval algorithms and develop a new one better adapted to the low concentrations encountered in the St. Lawrence estuary and Gulf.     

Studies of the structure of the Solovetsky reproductive gathering of beluga whales (<Emphasis Type="Italic">Delphinapterus leucas</Emphasis>) in the White Sea using the photo identification method

The structure of the reproductive gathering of beluga whales (RG) was studied near Cape Beluzhii in the Solovetsky Islands in the White Sea by the photo identification of individuals in 2007–2008; in addition, the peculiarities of the seasonal and interseasonal dynamics of the RG incomings were analyzed. The gathering is formed by predominantly females and calves of different ages, which visit the RG area as stable “family” groups. About 15% of the observed females come to Beluzhii Cape every year and stay there during the whole summer season; thus, forming the regular part of the RG. The other animals come there for a certain time period, which is probably preconditioned by their physiological readiness for coupling and procreation for some of the females. When comparing our data with the catalogue of the visually registered beluga whales’ markers (1996–2008), we found that most of the identified animals of the Solovetsky RG appear here during one summer season or even with an off period of several years despite the significantly regular findings of most of them for this area. We conclude this may be linked with the natural changes of the individual markers due both to the shedding and the sexual cycle in the mature animals. Our data allow concluding that the total population of the Solovetsky PG is higher than was reported before using the visual supervision methods.     

Polychlorinated biphenyls (PCBs) and their hydroxylated metabolites (OH-PCBs) in livers of harbor seals (Phoca vitulina) from San Francisco Bay,California and Gulf of Maine

Bioaccumulation of endocrine disruptors in marine mammals positioned at the top of the food chain is of toxicological concern. Livers from four pups and ten adult harbor seals (Phoca vitulina) stranded in San Francisco Bay (SFB) and the Gulf of Maine (GOM) were analyzed for polychlorinated biphenyls (PCBs) and their hydroxylated metabolites (OH-PCBs). We used GC–ECD and GC–NCI/MS to investigate the presence of 28 PCBs and 8 OH-PCB metabolites, respectively. Σ₂₈PCB concentrations (di- to octa-CBs) ranged from 1.81 to 35.9 μg/g lipid with a median of 6.53 for the seal pups and 2.31 to 249 μg/g lipid with a median of 28.9 for the adult seals. Σ₈OH-PCB concentrations (penta- to hepta-OH-PCBs) ranged from 0.02 to 0.69 μg/g lipid with a median of 0.04 for the adult seals, i.e., at much lower concentrations than those for PCBs. Ratios of OH-PCBs to PCBs (0.24% on average) were comparable to those in beluga whale, but were lower than ratios in human livers. The OH-PCB profiles were slightly different between SFB and GOM seal livers, although similar PCB congener patterns were observed. Generally, 4-OH-CB107 was found predominantly in seal livers and was the only OH-PCB detectable in most of seal pup livers. This study provides information on OH-PCBs in seals, adding to the scarce exposure data for these chemicals.     

Storms and shoreline retreat in the southern Gulf of St. Lawrence

Storms play a major role in shoreline recession on transgressive coasts. In the southern Gulf of St. Lawrence (GSL), southeastern Canada, long-term relative sea-level rise off the North Shore of Prince Edward Island has averaged 0.3 m/century over the past 6000 years (>0.2 m/century over 2000 years). This has driven long-term coastal retreat at mean rates >0.5 m/a but the variance and details of coastal profile response remain poorly understood. Despite extensive sandy shores, sediment supply is limited and sand is transferred landward into multidecadal to century-scale storage in coastal dunes, barrier washover deposits, and flood-tidal delta sinks. Charlottetown tide-gauge records show mean relative sea-level rise of 3.2 mm/a (0.32 m/century) since 1911. A further rise of 0.7±0.4 m is projected over the next 100 years. When differenced from tidal predictions, the water-level data provide a 90-year record of storm-surge occurrence. Combined with wind, wave hindcast, and sea-ice data, this provides a catalogue of potentially significant coastal storms. We also document coastal impacts from three recent storms of great severity in January and October 2000 and November 2001. Digital photogrammetry (1935–1990) and shore-zone surveys (1989–2001) show large spatial and temporal variance in coastal recession rates, weakly correlated with the storm record, in part because of wave suppression or coastal protection by sea ice. Large storms cause rapid erosion from which recovery depends in part on local sand supply, but barrier volume may be conserved by washover deposition. Barrier shores with dunes show high longshore and interdecadal variance, with extensive multidecadal healing of former inlet and overwash gaps. This reflects recovery from an episode of widespread overwash prior to 1935, possibly initiated by intense storms or groups of storms in the latter half of the 19th century. With evidence from the storms of 2000–2001, this points to the importance of storm clustering on scales of weeks to years in determining erosion vulnerability, as well as the need for a long-term, large-scale perspective in assessing coastal stability. The expected acceleration in relative sea-level rise, together with projections of increasing storm intensity and greatly diminished winter ice cover in the southern GSL, implies a significant increase in coastal erosion hazards in future.     

Distribution and sources of organochlorine pesticides in water and sediments from Daliao River estuary of Liaodong Bay,Bohai Sea (China)

The levels of 19 kinds of organochlorine pesticides (OCPs) in the aqueous phase, suspended particulate matter (SPM), pore water and sediments from Daliao River estuary of Liaodong Bay (Bohai Sea) in northeast China were investigated to evaluate their potential pollution risks. The total OCPs concentrations in the aqueous phase, SPM, pore water and sediments were 3.7–30.1 ng l⁻¹, 4.6–52.6 ng l⁻¹, 157–830 ng l⁻¹ and 2.1–21.3 ng g⁻¹ dry weight, respectively. The concentrations of OCPs, in the Daliao River estuary, are in the mid-range, as compared to those reported in other estuaries worldwide. The distribution of HCHs and DDTs were different indicating different contamination sources. Lindane is the main type of HCH and continuing use in northeast China of ‘pure’ HCH (lindane) rather than technical HCH accounts for the source. The ratios of (DDE + DDD)/DDT in the samples indicate no recent inputs of these chemicals to the estuary.     

Methane-derived authigenic carbonates from active hydrocarbon seeps of the St. Lawrence Estuary,Canada

Nearly 2000 pockmarks with diameters ranging from a few tens of meters up to 700 m are present on the seafloor of the St. Lawrence Estuary in eastern Canada. Coring of some pockmarks resulted in the recovery of various-sized and shaped carbonate concretions in a predominantly silty mud matrix. Petrographic and geochemical data on four authigenic carbonate concretions are reported as well as data from shell material in the unconsolidated sediment. Video observations and echo-sounder images indicate that the sampled pockmarks are actively gas venting. The video images show significant look-alike microbial mats in areas where gas is venting. The carbonate concretions are primarily made up of carbonate cements with varying percentage of shell fragments, micrite particles and fine-grained clastics. Orthorhombic crystal morphology and diagenetic fabrics including isopachous layers and botryoids characterize the aragonite cement. Oxygen isotopes ratios for the cement crusts do not record any thermal anomaly at the site of precipitation with δ¹⁸O_VPDB ratios (+3‰) in equilibrium with cold (5 °C) deep marine waters, whereas significant negative δ¹³C_VPDB ratios (−9.9 to −33.5‰) for cement and shell material within concretions indicate that the carbonates largely derive from the microbial oxidation of methane. The δ¹³C_VPDB ratios of aragonite shells (−2.7 to −5.6‰) taken from unconsolidated sediments at some distance from the concretions/vents show variable dilution of HCO₃⁻ with negative δ¹³C_VPDB ratios derived from microbial oxidation of methane with isotopically normal (0‰) marine bicarbonate. These results are in agreement with other lines of evidence suggesting that pockmarks formed through the recent and still active release of gas from a reservoir within the Paleozoic sedimentary succession.     

Histopathological observations on liver,kidney and gonad of plaice (Pleuronectes platessa) taken from the Mersey estuary

The Mersey estuary is the most contaminated estuary in British waters. Detailed studies are underway on the pathology of flounder (Platichthys flesus) from the Mersey and on flounder from the nearby, but less contaminated, Dee estuary. Flounder breed offshore but spend a lot of time in the estuaries, penetrating into freshwater. These flatfish are in close contact with sediments and will be exposed to exenobiotic stored in the sediments. Plaice (Pleuronectes platessa) are flatfish which enter the Mersey with the tidal flow but spend less time in the estuary than flounder and are less likely to show evidence of pollutant exposure. Over 20 plaice were collected from the Mersey. Samples of the liver, kidney and gonad were fixed in 10% formal saline, processed into paraffin wax and 5 microm sections cut and stained with haematoxylin and eosin. Liver changes consisted of variable amounts of glycogen/lipid storage product, minor perivenular and perivascular fibrosis, and helminth parasitisation. No tumours or foci of cellular alteration, necrosis and inflammation were seen. In the gonad only changes consistent with normal gonadal cycling was seen. These studies provide evidence that plaice show little or no evidence of toxic pathological damage resulting from their stay in the estuary.     

Spatio‐temporal variations in demersal fish assemblages and diversity in the northern Gulf of St. Lawrence (Canada)

Species diversity is generally considered one of the key factors of ecosystem resilience in response to anthropogenic pressures, including fishing. In this context, the spatial and temporal changes in demersal fish assemblages and species diversity were investigated in the northern Gulf of St. Lawrence (Canada), over a 20‐year period (1990–2010). Data were obtained from the summer research survey conducted by the Department of Fisheries and Oceans, and include commercial and non‐commercial species. The study covers the period of groundfish fishery collapse, the moratorium period, and the post‐moratorium period, and reflects various modifications in management. Multivariate statistical methods revealed two communities. A coastal community corresponds to strata located above 200 m depth and a deeper community located in the deep channels. Interannual differences in the composition of fish assemblages were observed and are mainly due to the changes in the relative biomass of some dominant species. Three diversity indices (Shannon–Wiener, Simpson's Index of Diversity and Motomura's constant) indicate a slight but significant increase of the diversity over time. This trend is due to the increase of the relative biomass of low‐rank species, which may have been favoured by the prohibition of groundfish trawling after 1997 in that region. The geographical distribution of the Shannon–Wiener index also shows temporal dynamics reflecting the biomass distribution of dominant demersal species.     

Pathology of the liver, kidney and gonad of flounder (Platichthys flesus) from a UK estuary impacted by endocrine disrupting chemicals.

The Mersey estuary is highly contaminated with xenobiotics compared to the nearby Dee estuary. Male flounder, a migratory flatfish caught in the Mersey frequently contains high blood concentrations of the oestrogen controlled, female protein vitellogenin, suggesting that Mersey flounder have been exposed to endocrine disrupting contaminants. Males caught from the Dee contain lower blood vitellogenin levels. Preliminary histopathological examination of 410 flounder from both estuaries, focuses on the liver, kidney and gonads. Hepatic tubular vacuolation, foci of cellular alteration, and hepatocellular tumours were seen. Renal and gonadal pathology included the presence of two Mersey fish with enlarged and abnormal glomeruli, three phenotypic male Mersey flounder with unilateral intersex gonads and one male with bilateral, abnormal ovarian follicular components in the testis. These initial results provide pathological evidence of xenobiotic exposure in flounder sampled from both estuaries. Preliminary findings from flounder sampled from Millport, an offshore site in Southwest Scotland, showed no histopathological evidence of xenobiotic exposure.