The role of organochlorines in cancer-associated mortality in California sea lions (Zalophus californianus)

Wild California sea lions (Zalophus californianus) have an unusually high prevalence of neoplasms (18% of stranded dead adults) and high levels of contaminants. The contribution of organochlorine (OC) tissue burdens to the probability of sea lions dying from carcinoma was explored using a logistic regression model. Levels of PCBs and DDTs were determined in blubber of sea lions diagnosed with metastatic carcinoma and animals that had died from non-carcinoma-related incidents (e.g., gunshot, domoic acid poisoning). Animals with carcinoma had higher mean concentrations (based on wet weight) of PCBs and DDTs (more than 85% and 30% higher, respectively) in blubber than did sea lions without carcinoma; the highest concentrations of OCs in the sea lions affected with carcinoma were measured in the males. Blubber thickness was significantly different between the two groups of sea lions, but after controlling for this difference, there was still a significant effect of PCBs, but not DDTs, on the probability of sea lions dying with carcinoma. Age, sex, mass and length did not affect the probability of dying from carcinoma.     

Determination of HBCD, PBDEs and MeO-BDEs in California sea lions (Zalophus californianus) stranded between 1993 and 2003

Blubber samples from male California sea lions (Zalphophus californianus) stranded between 1993 and 2003 were analyzed for 27 polybrominated diphenyl ether (PBDE) congeners, three isomers of hexabromocyclododecane (HBCD) and 14 methoxylated polybrominated diphenyl ether (MeO-BDE) congeners. Total PBDEs ranged from 450 ng/g to 4740 ng/g wet mass and total HBCD ranged from < 0.3 ng/g to 12 ng/g wet mass. The concentration of HBCD increased from 0.7 ng/g to12.0 ng/g wet mass in sea lion blubber between 1993 and 2003. However, no significant temporal trend was observed for any of the other brominated compounds over this 10 year period. Only one of the 14 MeO-BDE congeners was detected in the blubber samples, 6-methoxy-2,2',4,4'-tetrabromodiphenyl ether (6-MeO-BDE 47), and concentrations ranged from < 0.2 ng/g to 12 ng/g wet mass. A bromo-, chloro-heterocyclic compound, 1,1'-dimethyl-tetrabromo-dichloro-2,2'-bipyrrole (DBP-Br4Cl2), previously reported in marine species along the Pacific coast, was also identified in the sea lion blubber. DBP-Br4Cl2 ranged from 44 ng/g wet mass to 660 ng/g wet mass and was present at concentrations rivaling the dominant PBDE congener, BDE 47 (2,2',4,4'-tetrabromodiphenyl ether). Concentrations of DBP-Br4Cl2 were positively correlated with 6-MeO-BDE 47 (r = 0.7; p < 0.05). Both of these compounds have been identified in marine algae and sponges, and studies suggest they are both produced from natural sources. This study demonstrates that brominated compounds from both anthropogenic and biogenic sources can accumulate to similar levels in marine mammals. In addition, HBCD concentrations appear to be increasing in California sea lion populations, whereas PBDE concentrations, between 1993 and 2003, were highly variable.     

DDT in endangered Galapagos sea lions (Zalophus wollebaeki)

We characterize for the first time the presence of DDT and its metabolites in tropical Galapagos sea lions (Zalophus wolleabeki). ∑DDT concentrations in Galapagos sea lion pups sampled in 2005 and 2008 ranged from 16 to 3070 μg/kg lipid. Concentrations of ∑DDT in pups in 2008 averaged 525 μg/kg lipid and were 1.9 times higher than that (281 μg/kg lipid) detected in pups in 2005. These concentrations are lower than those reported in many pinnipeds elsewhere, comparable to those in Hawaiian monk seals, and higher than those in southern elephant seals. The health risk characterization showed that 1% of the male pups exceeded the p,p′-DDE toxic effect concentration associated with anti-androgenic effects reported in rats. The findings provide preliminary guidance on the relationship between DDT use and ecological impacts, serving as a reference point against which possible future impact of tropical DDT use can be assessed.     

Impacts of the Jessica oil spill on sea lion (Zalophus wollebaeki) populations

Following the Jessica oil spill, a total of 79 oiled Galápagos sea lions (Zalophus wollebaeki) were recorded around the islands of San Cristóbal, Santa Fé, Isabela and Floreana. Almost half of these animals required washing and other treatment. One sea lion death and a high incidence of conjunctivitis and burns were detected during the period of the oil spill. Sea lion populations exhibited a tendency for decline in the first months following the spill at all three colonies monitored close to the grounding site on San Cristóbal. By comparison, declines of similar magnitude occurred at only one of six sea lion colonies monitored on islands more distant from the spill. However, no significant decreases in population numbers were detected for any colony in the year following the spill. Galápagos sea lion populations were partially recovering from the much more catastrophic impact of the 1997/98 El Ni?o.     

Maternal-to-fetal transfer and concentration profiles of PCB congeners for Steller sea lions (Eumetopias jubatus) from Hokkaido,Japan

The concentrations of PCB congeners in the blubber and liver of mother Steller sea lions (Eumetopias jubatus; SSLs) and their fetuses from the coast of Hokkaido, Japan in 2008, 2010 and 2012 were analyzed by HRGC–HRMS, in order to elucidate PCB congener profiles and maternal-to-fetal transfer of PCBs in SSLs. ΣPCBs in the fetuses were 1400 ± 660 (the mean ± SD) ng/g-fat in the blubber and 570 ± 320 ng/g-fat in the liver, respectively. There was a concern that SSLs had been contaminated by PCBs during the fetal period. The concentrations of the major congeners in the blubber and liver were a correlation between the fetus and mother (blubber: r = 0.9934, liver: r = 0.9160; P ≦ 0.05). The results indicated that PCBs in the fetuses came from the mothers. #177 and #199 showed no correlations between the fetus and the mother in the blubber and liver. This indicated a selective capture by some natural protector such as the placenta.     

Seasonal changes in larval fish assemblages in a semi-enclosed sea (Gulf of California)

The northern Gulf of California (NGC) is characterized by seasonal hydrography and circulation (cyclonic in summer and anticyclonic in winter), by intense tidal mixing in the midriff archipelago region (MAR), and by coastal upwelling on the eastern side from autumn to spring. We examined changes in larval fish assemblages (LFAs) in relation with hydrography and circulation during both phases of the seasonal circulation, as indicators of changes in the pelagic ecosystem. A canonical correspondence analysis defined LFAs (r>0.70), which were related with: (i) the coastal current on the mainland shelf, (ii) the central eddy and (iii) the MAR. In the early cyclonic phase, when the temperature and stratification were increasing and the coastal current was starting, demersal (Gobulus crescentalis, Lythrypnus dalli) and mesopelagic species (Benthosema panamense) dominated the NGC. The highest larval abundance was in the Current LFA area and the lowest in the MAR LFA area. In the mature cyclonic phase, the larval abundance increased in the NGC and species characteristic of eastern boundary current systems such as Opisthonema libertate and Engraulis mordax displaced the demersal species and became dominant, together with B. panamense in the Current LFA area; the latter species dominated in the Eddy LFA area. In the early anticyclonic phase, the direction of the coastal current reversed and the temperature and larval abundance decreased. E. mordax and B. panamense larvae continued dominating the NGC with higher abundance in the MAR than in the Current and Eddy LFA areas. In the mature anticyclonic phase, E. mordax larvae dominated in the Current and the Eddy LFA areas with the highest abundance in the former, while M. productus larvae (an eastern boundary current species) dominated in the Eddy LFA area. Results showed that in the NGC, the dramatically seasonal and predictable hydrographic and circulation features trigger the seasonal spawning of the dominant species. The biological richness of the coastal current area, in both circulation phases, suggested that this area has an important role in the pelagic ecosystem functionality of the NGC.     

Entanglement of Steller sea lions (Eumetopias jubatus) in marine debris: Identifying causes and finding solutions

Entanglement in marine debris is a contributing factor in Steller sea lion (SSL; Eumetopias jubatus) injury and mortality. We quantified SSL entanglement by debris type, sex and age class, entanglement incidence, and estimated population level effects. Surveys of SSL haul-outs were conducted from 2000-2007 in Southeast Alaska and northern British Columbia. We recorded 386 individuals of all age classes as being either entangled in marine debris or having ingested fishing gear. Packing bands were the most common neck entangling material (54%), followed by rubber bands (30%), net (7%), rope (7%), and monofilament line (2%). Ingested fishing gear included salmon fishery flashers (lures: 80%), longline gear (12%), hook and line (4%), spinners/spoons (2%), and bait hooks (2%). Entanglement incidence was 0.26% (SD = 0.0064, n = 69 sites). “Lose the Loop!” Simple procedures such as cutting entangling loops of synthetic material and eliminating the use of packing bands can prevent entanglements.     

Evaluation of diffusive gradients in thin-films (DGTs) as a monitoring tool for the assessment of the chemical status of transitional waters within the Water Framework Directive

In this contribution, the potential use of diffusive gradients in thin-films (DGTs) for the chemical evaluation of transitional water bodies within the Water Framework Directive (WFD) has been studied. The water metal concentration has been evaluated in 13 estuaries in the southeastern Bay of Biscay. The DGTs were deployed in triplicate at two stations in each estuary, delimiting the tidal influence. The DGT results were in the ranges of 2-1570 ng L(-1) for cadmium, 66-515 ng L(-1) for copper, 30-3650 ng L(-1) for nickel and 0.8-95.5 μg L(-1) for zinc. The DGTs provided reliable average labile metal concentrations in highly dynamic systems that were comparable with DGT measurements in coastal and estuarine waters worldwide. In addition, it was possible to discriminate those estuaries more susceptible to environmental impacts, being consistent with the historical contamination of each estuary. Based on the obtained results, a sampling strategy for the monitoring of transitional water bodies using DGTs is proposed.     

Biomarkers of exposure and effect in flounder (Platichthys flesus) exposed to sediments of the Adriatic sea.

The modifications of several biomarkers were investigated in flounder (Platichthys flesus) when exposed in the laboratory to sediment samples collected from the Northern Adriatic Sea. Besides clean sand used as a control substrate, fish were exposed to sediments sampled offshore the delta of the Po River, the harbour of Trieste, and from the industrial harbour of Venice (Porto Marghera). After six days of exposure, the enzyme activities ethoxyresorufin-O-deethylase (EROD), UDP glucuronyltransferase (UDPGT), glutathione S-transferase (GST), glutathione reductase (GR) and glutathione peroxidase (GPx), were assayed in fish liver. In addition, the contents of reduced glutathione (GSH), nonprotein thiols (SH), total sugars and extractable lipids were also determined in hepatic tissue, as well as the number of micronucleated hepatocytes and biliary concentrations of fluorescent aromatic compounds (FAC). Despite some variability within treatment groups, differences among exposed organisms were evident and consistent with known contaminant levels of sampled areas. Microsomal activities (EROD, UD-PGT) and FAC levels were the most sensitive exposure indicators. Variations in the other biomarkers showed only tendencies which although not statistically significant were generally consistent with the contamination pattern.     

Probabilistic seismic hazard assessment for the two layer fault system of Antalya (SW Turkey) area

Southwest Turkey, along Mediterranean coast, is prone to large earthquakes resulting from subduction of the African plate under the Eurasian plate and shallow crustal faults. Maximum observed magnitude of subduction earthquakes is Mw = 6.5 whereas that of crustal earthquakes is Mw = 6.6. Crustal earthquakes are sourced from faults which are related with Isparta Angle and Cyprus Arc tectonic structures. The primary goal of this study is to assess seismic hazard for Antalya area (SW Turkey) using a probabilistic approach. A new earthquake catalog for Antalya area, with unified moment magnitude scale, was prepared in the scope of the study. Seismicity of the area has been evaluated by the Gutenberg-Richter recurrence relationship. For hazard computation, CRISIS2007 software was used following the standard Cornell-McGuire methodology. Attenuation model developed by Youngs et al. Seismol Res Lett 68(1):58–73, (1997) was used for deep subduction earthquakes and Chiou and Youngs Earthq Spectra 24(1):173–215, (2008) model was used for shallow crustal earthquakes. A seismic hazard map was developed for peak ground acceleration and for rock ground with a hazard level of a 10% probability of exceedance in 50 years. Results of the study show that peak ground acceleration values on bedrock change between 0.215 and 0.23 g in the center of Antalya.     

Utility of the Hadley Centre sea ice and sea surface temperature data set (HadISST1) in two widely contrasting coral reef areas

The HadISST1 sea surface temperature data set is examined for two contrasting areas: the Chagos Archipelago, central Indian Ocean which has a small (approximately 3 degrees C) annual temperature fluctuation, and Abu Dhabi in the southern Arabian Gulf whose annual air temperature fluctuation of approximately 24 degrees C is the largest known for coral reef habitats. The HadISST1 data are shown to match air temperature records closely, both in terms of annual moving averages and residual analysis. Temperatures in 1998 caused massive mortality of corals in the Indian Ocean: sea surface temperature (SST) values causing this were 33.8 degrees C in the Arabian Gulf at a time when average daily air temperature was over 40 degrees C, while in Chagos the SST lethal to corals was 29.8-29.9 degrees C, when air temperatures peaked at about 31 degrees C. The HadISST1 record was searched back to 1870 for previous abnormal peaks: one of 29.7 degrees C was found for Chagos SST in 1972, though this did not cause coral mortality. Analysis of 12-month running means of the residuals from the annual cycle show that, between 1870 and 1999, the largest SST deviations occurred between October 1997 and May 1998 in Chagos and between August 1998 and July 1999 near Abu Dhabi. The event of 1998-1999 was the largest in these regions for at least 130 years. SSTs have risen over the last three decades at rates of about 0.22 degrees or 0.23 degrees per decade in both locations.     

Incorporation of in situ exposure and biomarkers response in clams Ruditapes philippinarum for assessment of metal pollution in coastal areas from the Maluan Bay of China

The clams Ruditapes philippinarum were used to assess the impact of metal contaminants when transplanted to seven study sites along the Maluan Bay (China). Metal concentrations in digestive gland tissues of clams after 7-day in situ cage exposure were determined in conjunction with antioxidant enzyme activities. The results showed the importance of specific antioxidant biomarkers to assess complex pollutant mixtures and their good correlations to the pollutant compositions of deployment sites. Multivariate analysis indicated causal relationship between the chemicals at each study site and the biochemical "response" of the caged clams at these sites and demonstrated the potential presence of two different contaminant sources. This study suggested that the incorporation of tissue residue analysis with biomarkers response in caged clams together with factor analysis can be a useful biomonitoring tool for the identification of causal toxic pollutants and the assessment of complex metal pollutions in marine coastal environment.     

Seasonal variations of physiological and cellular biomarkers and their use in the biomonitoring of north Adriatic coastal waters (Croatia)

Lysosomal membrane stability, the content of neutral lipids and lipofuscin as cellular biomarkers were measured in the digestive gland of mussels, Mytilus galloprovincialis Lam., during a one year survey at selected sites along the coast of the northern Adriatic. The ability of mussels to survive in air as a general physiological response was tested at the same sites. Annual changes of sea temperature, salinity, O(2) saturation, pH and chlorophyll a concentration were measured and the effects of these environmental factors on the biomarkers selected for this study were determined. Survival of mussels after aerial exposure was significantly (p < 0.05) reduced in mussels collected from the contaminated harbors of Pula and Rijeka compared to clean control sites. Lysosomal membrane stability of mussels from urban and industrial areas was also lower indicating exposure to different environmental contaminants. At the same sites, the content of neutral lipids and lipofuscin in digestive cells was significantly higher compared to the reference sites, suggesting alterations in lipid metabolism and contaminant-induced peroxidation of cell membranes. The greatest influence of natural environmental factors was observed for the aerial survival of mussels and the neutral lipids and lipofuscin content in the digestive gland, indicating that the annual cycles of biomarker responses should be well understood for a correct interpretation of biomonitoring results.     

An evaluation of hemolymph cholinesterase activities in the tropical scallop,Euvola (Pecten) ziczac,for the rapid assessment of pesticide exposure

The use of sequential measurements of hemolymph cholinesterase activities as a non-invasive biomarker of seasonal organophosphate/carbamate exposure was investigated for the tropical scallop, Euvola (Pecten) ziczac. Overall activities of both acetylcholinesterase and butyrylcholinesterase were relatively high compared to studies with bivalve tissues. Acute in vivo experiments showed inhibition of hemolymph acetylcholinesterase activity at concentrations of the organophosphate insecticide chlorpyrifos of 0.1, 1 and 10 ng l(-1). Monthly sampling of hemolymph from scallops at two sites in Bermuda over a 15 month period showed seasonal acetylcholinesterase and butyrylcholinesterase inhibition. Direct and indirect evidence suggests that this inhibition did not relate to biochemical or physiological changes associated with gonad maturation and spawning, but rather reflected diffuse contamination of the marine environment by cholinesterase inhibitors or increased bioavailability of such inhibitors at these times. Repetitive sampling of scallop hemolymph for cholinesterase activities represents a rapid, sensitive and non-invasive method for assessing seasonal, sublethal pesticide exposure in these commercially important bivalves and suggests a wider use in marine pollution monitoring.     

The flavour and chemical assessment of dabs (Limanda limanda) caught in the vicinity of the Beatrice Oil Platform

Dabs (Limanda limanda) caught in close proximity to the Beatrice Oil Platform have been assessed for the presence of an oil taint and chemically analysed for n-alkane and polynuclear aromatic hydrocarbons.Although contamination from petrogenic hydrocarbons was apparent, none of the fish were found to have a definite taint.     

Contamination status and accumulation profiles of organotins in sea otters (Enhydra lutris) found dead along the coasts of California, Washington, Alaska (USA), and Kamchatka (Russia)

Organotin compounds (OTs) including mono- to tri-butyltins, -phenyltins, and -octyltins were determined in the liver of adult sea otters (Enhydra lutris) found dead along the coasts of California, Washington, and Alaska in the USA and Kamchatka, Russia. Total concentrations of OTs in sea otters from California ranged from 34 to 4100ng/g on a wet weight basis. The order of concentrations of OTs in sea otters was total butyltins>total octyltins> or = total phenyltins. Elevated concentrations of butyltins (BTs) were found in some otters classified under 'infectious-disease' mortality category. Concentrations of BTs in few of these otters were close to or above the threshold levels for adverse health effects. Total butyltin concentrations decreased significantly in the livers of California sea otters since the 1990s. Based on the concentrations of organotins in sea otters collected from 1992 to 2002, the half-lives of tributyltin and total butyltins in sea otters were estimated to be approximately three years.     

Organic biomarkers for tracing carbon cycling in the Gulf of Papua (Papua New Guinea)

Sediment traps were deployed in the Gulf of Papua in June–July 1997, to determine fluxes of organic matter and inorganic elements from the photic zone to deeper waters at the base of the continental slope and in the northern Coral Sea. Three stations, ranging from 900 to 1500 m depth, had “shallow” traps at 300 m below the water surface and “deep” traps set 100 m above the bottom. Infiltrex II water samplers collected particulate and dissolved organic matter from the Fly, Purari and Kikori rivers, and near-surface water from the shelf of the Gulf of Papua. Samples were analysed for molecular organic biomarkers to estimate the sources of organic carbon and its cycling processes.Dry weight fluxes from the shallow traps ranged from 115 to 181 mg m⁻² day⁻¹ and particulate organic carbon (POC) fluxes ranged from 1.2 to 1.9 mM OC m⁻² d⁻¹ with molar organic carbon to particulate nitrogen ratios (C/N) ranging from 6.0 to 6.5. Fluxes in deep traps were likely influenced by both early diagenesis and entrapment of resuspended shelf sediments. Dry weight fluxes in deep traps ranged from 106 to 574 mg m⁻² day⁻¹ and POC fluxes ranged from 0.6 to 1.5 mM OC m⁻² d⁻¹, with C/N ratios ranging from 8.5 to 10.8. ¹³C/¹²C ratios were −20.2‰ to −21.7‰ in all trap samples, indicating that most of the settling POC was “marine-derived”. Shallow traps had δ¹⁵N values of 6.3‰ to 7.2‰ while the values in deep traps were 4.9–5.0‰, indicating the N-rich near-surface OC was less degraded than that in the deep traps. The biogenic lipids consisted of hydrocarbon, sterol and fatty acid biomarkers indicative of marine zooplankton, phytoplankton and bacteria. Sterol markers for diatoms and dinoflagellates were abundant in the water samples. Highly branched isoprenoid alkenes, usually attributable to diatoms, were also detected in both water and shallow traps. Traces of C₂₆–C₃₄ n-alcohols indicative of land–plant biomarkers, were found in river water samples and in the shallow sediment traps. A large unresolved complex mixture (UCM) of hydrocarbons, and a uniform distribution of n-alkanes, indicative of petroleum hydrocarbons, were also detected in the traps. Hopane and sterane biomarkers detected in the trap oil were characteristic of a marine carbonate source, and the aromatic hydrocarbon composition distinguished at least two different oil signatures.We concluded that mass and POC fluxes were similar to those reported for other continental shelves and marginal oceans in tropical and subtropical regions. There was a dramatic decrease in POC as particles sank, due to zooplankton repackaging and photochemical and bacterial decomposition. Carbon isotopic and biomarker patterns showed most of the POC in the sediment traps was marine-sourced with only traces of terrestrial input. There was a significant flux of petroleum, which may signal the existence of natural petroleum seeps in this region.