Glaucous Gulls Larus Hyperboreus Research Articles

Chromosome Aberrations and DNA Strand Breaks in Glaucous Gull (Larus Hyperboreus) Chicks Fed Environmentally Contaminated Gull Eggs

In this present laboratory study, our results suggest that a complex mixture of pollutants found in the marine environment exerts genotoxic effects on glaucous gull (Larus hyperboreus) chicks fed environmentally contaminated gull eggs. Chromosome aberrations, quantified by cytogenetic analysis of blood cells, and DNA strand breaks, quantified by agarose gel electrophoresis and image data analysis, were determined in glaucous gull chicks fed environmentally contaminated gull eggs (exposed group) and in chicks fed hen eggs (control group). For both female and male gulls, the fraction of damaged metaphases was quantitatively higher in exposed than in control groups. On the other hand, the differences between the control and the exposed groups were more relevant when the chromosomal aberration data were treated as group totals rather than at the individual level. Consistent results were obtained in the DNA strand break analyses. The control group appeared to display a greater median molecular length (MML) than the exposed group.

Pinpointing Potential Causative Agents in Mixtures of Persistent Organic Pollutants in Observational Field Studies: A Review of Glaucous Gull Studies

Since different organochlorine contaminants (OCs) are often highly correlated in biota, a major challenge in observational field studies is to establish whether some OCs are potentially important causative agents of adverse effects. A possible solution to this problem is to compare the strength of the effects of different OCs on a number of outcome parameters, and then examine if some compounds are more consistently reliable predictors of adverse effects. In this analysis the four most common OCs (hexachlorobenzene [HCB], oxychlordane, p,p′- dichlorodiphenyldichloroethylene[DDE], and polychlorinated biphenyls [PCBs]) in arctic glaucous gulls (Larus hyperboreus) were ranked in relation to 19 different outcome parameters, for which at least 1 of the 4 OCs were significantly related. PCBs, made up close to 75% of the measured ∑OCs, DDE 17–18%, and HCB and oxychlordane 3–4%, respectively. Despite relatively low levels of oxychlordane and HCB, these compounds tended to be more reliable predictors of adverse effects and were ranked highest for 11 and 10 of the 19 outcome parameters, respectively. PCBs and DDE were only ranked highest for seven of the outcome parameters. Oxychlordane, HCB, DDE, and PCB were “not significant” two, six, six, and eight times, respectively. Oxychlordane was significantly more likely to be related to adverse effects than DDE. Even if effects of OCs may depend on a complex interaction between different compounds, this analysis indicates that adverse effects are more likely to occur in glaucous gulls with relatively high concentrations of oxychlordane and HCB.

Changes in the Glaucous Gull Predatory Pressure on Little Auks in Southwest Spitsbergen

Abstract The impact of Glaucous Gull (Larus hyperboreus) predation on the Little Auk (Alle alle) during breeding season at the Ariekammen slopes in Hornsund was compared between 1983 and 2003-04. During the nestling period, gulls killed more young Little Auks in 1983 than in 2003. During the period of the colony departure in 2003, there were more Glaucous Gulls present and they killed more Little Auks than 20 years previous. Changes were found in the strategy of the colony departure by the Little Auk. In 2004, the rate of fledglings departed from the colony during “day” hours was higher than in 1983 and a higher proportion of fledglings left the colony escorted by more than one adult bird. This could be a consequence of general increase in the Glaucous Gull numbers or a year-to-year fluctuation and needs further investigations.

New organochlorine contaminants and metabolites in plasma and eggs of glaucous gulls (Larus hyperboreus) from the Norwegian Arctic

The present study investigated new or lesser-studied and legacy organochlorine (OC) contaminants and metabolites in plasma and eggs of glaucous gulls (Larus hyperboreus) collected from major breeding colonies on Bear Island in the Norwegian Arctic. Hexachlorobutadiene was below the method limit of detection (< 0.07 ng/g lipid wt) in all samples. The sum (sum) of 20 chlorobornane congener concentrations ranged between 294 and 986 ng/g lipid weight and 104 and 1,121 ng/g lipid weight in plasma and eggs, respectively, whereas those of sum 20polychlorinated naphthalene ranged between 1.34 and 126 ng/g lipid weight in plasma and 1.82 and 162 ng/g lipid weight in eggs. Bis(4-chlorophenyl) sulfone concentrations ranged between 5.24 and 143 ng/ g lipid weight plasma, which is the first report of this contaminant in arctic biota north of Sweden. Based on 2,3,7,8-tetrachlorodibenzo-p-dioxin toxic equivalents (TEQs), partial dioxin-like toxicity varied between 3.04 and 20.8 ng TEQ/g lipid weight in plasma and 0.94 and 46.5 ng TEQ/g lipid weight in eggs, and largely was due to concentrations of non-ortho polychlorinated biphenyls (PCBs), with a very minor contribution from mono-ortho PCBs and polychlorinated naphthalenes. The major aryl sulfone metabolite in plasma was an unidentified hexachlorinated MeSO2-PCB congener (range: 13.5-551 ng/g lipid wt), whereas the pentachlorinated congeners 3'- and 4'-MeSO2-CB101 (range: 4.49-38.1 ng/g lipid wt) dominated in eggs. The predominant halogenated phenolic compound (HPC) in plasma was consistently the PCB metabolite 4-OH-CB187 (range: 0.29-17.5 ng/g wet wt), whereas in eggs, detectable HPCs were at very low and transient concentrations. As part of a complex profile of contaminant exposure, these chemical classes and metabolites may be contributing factors to enhance physiological stress in breeding glaucous gulls.

Perfluorinated Alkyl Substances in Plasma, Liver, Brain, and Eggs of Glaucous Gulls (Larus hyperboreus) from the Norwegian Arctic

Recent environmental surveys have ascertained the widespread occurrence of perfluorinated alkyl substances (PFAS) in tissues of wildlife from the Arctic. In the present study, we investigated the distribution of a suite of PFAS in plasma, liver, brain, and egg samples from adult glaucous gulls (Larus hyperboreus), an apex scavenger-predator seabird breeding in the Norwegian Arctic. Perfluorooctane sulfonate (PFOS) was the predominant PFAS in all samples and was present at concentrations that are the highest reported thus far in any arctic seabird species and populations. Among the body compartment/ tissue samples analyzed, PFOS was highest in plasma (48.1-349 ng/g wet weight (ww)), followed by liver approximately equal to egg > brain. Perfluorocarboxylic acids (PFCAs) with 8-15 carbon (C) atoms were found, with the highest concentrations determined in plasma (sum PFCA: 41.8-262 ng/g ww), whereas 5C- and 6C-PFCAs were below the limits of detection. Perfluorobutane sulfonate, perfluorooctane sulfonamide, and four saturated (8:2 FTCA and 10:2 FTCA) and unsaturated (8:2 FTUCA and 10:2 FTUCA) fluorotelomer carboxylic acids were not detected in any samples. Perfluorohexane sulfonate was measured at concentrations up to 2.71 ng/g ww. The accumulation profiles of PFCAs were characterized by high proportions of the long and odd-numbered carbon-chain-length compounds, namely perfluoroundecanoic (11C) and perfluorotridecanoic acid (13C), although their individual contribution differed between the matrixes analyzed. Current PFAS concentrations suggest a bioaccumulation potential in Norwegian arctic glaucous gulls that needs to be assessed as part of a broad organohalogen contaminant cocktail with potential for mediating biological processes in this vulnerable top-predator marine species.

Flame Retardants and Methoxylated and Hydroxylated Polybrominated Diphenyl Ethers in Two Norwegian Arctic Top Predators: Glaucous Gulls and Polar Bears

The brominated flame retardants have been subject of a particular environmental focus in the Arctic. The present study investigated the congener patterns and levels of total hexabromocyclododecane (HBCD), polybrominated biphenyls, polybrominated diphenyl ethers (PBDEs), as well as methoxylated (MeO) and hydroxylated (OH) PBDEs in plasma samples of glaucous gulls (Larus hyperboreus) and polar bears (Ursus maritimus) from the Norwegian Arctic. The analyses revealed the presence of total HBCD (0.07-1.24 ng/g wet wt) and brominated biphenyl 101 (< 0.13-0.72 ng/g wet wt) in glaucous gull samples whereas these compounds were generally found at nondetectable or transient concentrations in polar bears. Sum (sigma) concentrations of the 12 PBDEs monitored in glaucous gulls (range: 8.23-67.5 ng/g wet wt) surpassed largely those of polar bears (range: 2.65-9.72 ng/g wet wt). Two higher brominated PBDEs, BDE183 and BDE209, were detected, and thus bioaccumulated to a limited degree, in glaucous gulls with concentrations ranging from < 0.03 to 0.43 ng/g wet wt and from < 0.05 to 0.33 ng/g wet wt, respectively. In polar bear plasma, BDE183 was < 0.04 ng/g wet wt for all animals, and BDE209 was only detected in 7% of the samples at concentrations up to 0.10 ng/g wet wt. Of the 15 MeO-PBDEs analyzed in plasma samples, 3-MeO-BDE47 was consistently dominant in glaucous gulls (sigmaMeO-PBDE: 0.30-4.30 ng/g wet wt) and polar bears (sigmaMeO-PBDE up to 0.17 ng/g wet wt), followed by 4'-MeO-BDE49 and 6-MeO-BDE47. The 3-OH-BDE47, 4'-OH-BDE49, and 6-OH-BDE47 congeners were also detected in glaucous gulls (sigmaOH-PBDE up to 1.05 ng/g wet wt), although in polar bears 4'-OH-BDE49 was the only congener quantifiable in 13% of the samples. The presence of MeO- and OH-PBDEs in plasma of both species suggests possible dietary uptake from naturally occurring sources (e.g., marine sponges and green algae), but also metabolically derived biotransformation of PBDEs such as BDE47 could be a contributing factor. Our findings suggest that there are dissimilar biochemical mechanisms involved in PCB and PBDE metabolism and accumulation/elimination and/or OH-PBDE accumulation and retention in glaucous gulls and polar bears.

Validation of a screening method based on liquid chromatography coupled to high-resolution mass spectrometry for analysis of perfluoroalkylated substances in biota

A screening method for analysis of perfluoroalkylated substances (PFAS) in biota samples has been developed and validated using liver samples from polar cod ( Boreogadus saida) and glaucous gull ( Larus hyperboreus). The method was based on extraction of target compounds from homogenised samples into the solvent mixture used as mobile phase in high-performance liquid chromatography (HPLC), i.e. methanol/water (50:50; 2 mM ammonium acetate). The extract was filtered and directly injected into a HPLC/time-of-flight mass spectrometry (TOF-MS) system. Quantification was performed using 7 H-perfluoroheptanoic acid as internal standard and a calibration standard solution dissolved in sample extract for each matrix type (matrix-matched calibration standard). The method is very time and cost efficient. Except for long-chain compounds and perfluorooctane sulfonamide (which cannot be covered by this method), recoveries were between 60% and 115% and method detection limits were in the range 0.04–1.3 ng/g wet weight. Blank values could be neglected with the exception of perfluorooctane sulfonate (PFOS), perfluorohexanoic acid (PFHxA) and perfluorooctanoic acid (PFOA). One of the major challenges in PFAS analysis is ionisation disturbance by co-eluting matrix in the ion source of the mass spectrometer. Both matrix and analyte specific signal enhancement and suppression was observed and quantified. Repeated extractions ( n = 3) gave relative standard deviations (RSD) <35% for all PFAS. Accuracy was examined by comparing the screening method to the generally applied ion pair extraction (IPE) method. PFAS concentration values of a glaucous gull liver sample deviated by less than 30% for the two methods, provided that matrix-matched calibration standards were employed in both methods.

Dietary responses of arctic foxes Alopex lagopus to changing prey availability across an Arctic landscape

Abstract This study examines how the distribution and abundance of prey species influenced arctic fox Alopex lagopus diet on Svalbard during the summers of 1997, 1998 and 1999. The arctic fox together with the glaucous gull Larus hyperboreus are the only predators of this terrestrial ecosystem, and during summer the potential prey are confined to a few prey species such as various colonial seabirds, geese and Svalbard reindeer Rangifer tarandus platyrhynchus. There is great variation in distribution of prey over short distances, resulting in highly contrasting patterns in terms of both prey abundance and availability. Arctic fox diet was investigated by collecting scats (N = 818) at dens used for breeding. A cluster analysis based on similarities in the contents of scats revealed that arctic fox habitat could be divided into three distinct prey resource landscapes: two inland areas dominated by the prey species 'reindeer' and 'reindeer and geese', respectively, and one coastal resource area dominated by '...

Relationships between ecological variables and four organochlorine pollutants in an artic glaucous gull ( Larus hyperboreus) population

The Arctic has become a sink for organochlorine contaminants (OCs) from lower latitudes, and relatively high levels have been found in different biota. Recent studies of the glaucous gull, Larus hyperboreus, a top predator in the arctic food web, have documented that high blood residues of various OCs are related to lower reproductive performance and reduced adult survival. Here we provide additional evidence that OCs are having ecological effects in the glaucous gull population at Bear Island in the Norwegian Arctic, and compare the effects of the four major OCs found in the glaucous gulls: HCB, oxychlordane, DDE and PCBs, which made up >95% of measured OCs. Firstly; it has previously been shown that gulls with high levels of PCBs in their blood spent more time away from the nest site during incubation than gulls with low levels. Here we reanalyzed the data and found that PCBs ( P<0.02) and oxychlordane ( P<0.05) were positive and significantly related to time away from the nest site, while DDE and HCB were not related to this trait. Secondly, among females which bred in an area where fish dominated the diet, and thus had high flight costs during feeding, early chick growth was negatively related to maternal levels of all four OCs, especially HCB and DDE ( P<0.01). On the contrary, among females breeding in an area where the diet was dominated by eggs and young from nearby seabird colonies, and thus feeding costs were low, there were no effects of OC levels on early chick growth. This indicates that additional stress may be fundamental in causing reproductive effects of OCs in this population. Finally, during three breeding seasons we examined the probability of adults returning to the breeding grounds in the subsequent season, as a function of blood concentration of the four OCs. Overall, return rate from one year to the next was negatively related to blood residues of oxychlordane ( P=0.02), but not significantly related to the other three compounds. Further support for the importance of oxychlordane was that a 60% drop in the blood levels between 1997 and 2000 led to a significant increase in return rate between these two years.

Cytochrome P4501A induction and DNA adduct formation in glaucous gulls ( Larus hyperboreus), fed with environmentally contaminated gull eggs

This study indicates that complex mixtures of pollutants found in the Arctic marine environment have genotoxic effects in glaucous gulls ( Larus hyperboreus). DNA adducts were quantified, by the 32P-postlabeling technique, in liver samples from gulls fed with hen eggs (controls) and from gulls fed with environmentally contaminated gull eggs (exposed). All birds were grown and fed under laboratory conditions. Hepatic homologues to mammalian cytochrome P4501A (CYP1A) proteins were also determined by Western blotting. DNA adducts were detected in all but one liver sample, but the exposed birds had a significantly increased level of DNA adducts relative to that of the controls. There was no clear significant correlation between the DNA adduct level and the level of organochlorine compounds (OCs) in blood. The level of CYP1A protein was significantly higher in the liver of exposed male gulls than in the liver of control males and positively correlated, with significance, to the level of OC compounds measured in blood. There was no significant correlation between the level of DNA adducts and the CYP1A protein content.

Fluorinated Organic Compounds in an Eastern Arctic Marine Food Web

An eastern Arctic marine food web was analyzed for perfluorooctanesulfonate (PFOS, C8F17SO3-), perfluorooctanoate (PFOA, C7F15COO-), perfluorooctane sulfonamide (PFOSA, C8F17SO2NH2), and N-ethylperfluorooctane sulfonamide (N-EtPFOSA, C8F17SO2NHCH2CH3) to examine the extent of bioaccumulation. PFOS was detected in all species analyzed, and mean concentrations ranged from 0.28 +/- 0.09 ng/g (arithmetic mean +/- 1 standard error, wet wt, whole body) in clams (Mya truncata) to 20.2 +/- 3.9 ng/g (wet wt, liver) in glaucous gulls (Larus hyperboreus). PFOA was detected in approximately 40% of the samples analyzed at concentrations generally smaller than those found for PFOS; the greatest concentrations were observed in zooplankton (2.6 +/- 0.3 ng/g, wet wt). N-EtPFOSA was detected in all species except redfish with mean concentrations ranging from 0.39 +/- 0.07 ng/g (wet wt) in mixed zooplankton to 92.8 +/- 41.9 ng/g (wet wt) in Arctic cod (Boreogadus saida). This is the first report of N-EtPFOSA in Arctic biota. PFOSA was only detected in livers of beluga (Delphinapterus leucas) (20.9 +/- 7.9 ng/g, wet wt) and narwhal (Monodon monoceros) (6.2 +/- 2.3 ng/g, wet wt), suggesting that N-EtPFOSA and other PFOSA-type precursors are likely present but are being biotransformed to PFOSA. A positive linear relationship was found between PFOS concentrations (wet wt) and trophic level (TL), based on delta15N values, (r2 = 0.51, p < 0.0001) resulting in a trophic magnification factor of 3.1. TL-corrected biomagnification factor estimates for PFOS ranged from 0.4 to 9. Both results indicate that PFOS biomagnifies in the Arctic marine food web when liver concentrations of PFOS are used for seabirds and marine mammals. However, transformation of N-EtPFOSA and PFOSA and potential other perfluorinated compounds to PFOS may contribute to PFOS levels in marine mammals and may inflate estimated biomagnification values. None of the other fluorinated compounds (N-EtPFOSA, PFOSA, and PFOA) were found to have a significant relationship with TL, but BMF(TL) values of these compounds were often >1, suggesting potential for these compounds to biomagnify. The presence of perfluorinated compounds in seabirds and mammals provides evidence that trophic transfer is an important exposure route of these chemicals to Arctic biota.

Immune Function and Organochlorine Pollutants in Arctic Breeding Glaucous Gulls

Organochlorine contaminants (OCs) are known to affect the immune systems of wildlife, and in this study we assessed the relationship between blood concentration of different OCs and measurements relevant to immune status and function in arctic breeding glaucous gulls (Larus hyperboreus). In 1997 and 2001, we counted white blood cells (heterophils and lymphocytes) from blood smears, and in 2000 and 2001 we injected two novel nonpathogenic antigens (diphtheria and tetanus toxoids) into the pectoral muscle of gulls and measured the primary antibody responses. We then related these measurements to the blood concentrations of three pesticides (hexachlorobenzene [HCB], oxychlordane, and p,p'-dichlorodiphenyldichloroethylene) and seven different polychlorinated biphenyl congeners (PCB 101, 99, 118, 153, 138, 180, and 170). There were significant or near significant positive relationships (0.1 > p > 0.001) between most persistent OCs and the levels of heterophils in the blood for both sexes in 1997 and for male gulls in 2001. Similarly, levels of all persistent OCs and lymphocytes were positively related (0.1 > p > 0.001) in both sexes in 1997. This suggests that OCs are causing alterations to immune systems, which may decrease their efficiency and make the birds more susceptible to parasites and diseases. In female gulls, the antibody response to the diphtheria toxoid was significant and negative for HCB (p < 0.01) and weaker, but significant, for oxychlordane (p < 0.05), suggesting that OCs were causing an impairment of the humoral immunity. Various OCs have been linked to negative effects in our study population, including decreased survival and reproduction, and this study suggests that such compounds also affect immune status and function.

Effects of organochlorine contaminants on thyroid hormone levels in Arctic breeding glaucous gulls, Larus hyperboreus.

Studies on glaucous gulls (Larus hyperboreus) breeding in the Barents Sea have reported that high blood levels of halogenated organic contaminants in this species might cause reproductive, behavioral, and developmental stress. However, potential endocrine system modulation caused by contaminant exposure has yet not been reported in this Arctic apical predator. In this present study we aimed to investigate whether the current levels of a selection of organochlorines (OCs) were associated with altered circulating levels of thyroid hormones (THs) in free-ranging adult glaucous gulls breeding at Bear Island in the Barents Sea. Blood concentrations of 14 polychlorinated biphenyls, hexachlorobenzene (HCB), oxychlordane, and p,p' -dichlorodiphenyldichloroethylene (p,p' -DDE) were quantified, in addition to free and total thyroxine (T4) and triiodothyronine (T3), in plasma of 66 glaucous gulls in the spring of 2001. Negative correlations were found between plasma levels of T4 and T4:T3 ratio, and blood levels of OCs in male glaucous gulls. Despite their relatively low contribution to the total OC fraction, HCB and oxychlordane were the most prominent compounds in terms of their negative effect on the variation of the T4:T3 ratio. Moreover, lower T4 levels and T4:T3 ratios were measured in glaucous gulls breeding in a colony exposed to high levels of OCs, compared with a less exposed colony. Levels of T3 were elevated in the high-OC-exposed colony. This may indicate that the glaucous gull is susceptible to changes to TH homeostasis mediated by exposure to halogenated organic contaminants.

GLAUCOUS GULL PREDATION OF GOSLINGS ON THE YUKON-KUSKOKWIM DELTA, ALASKA

Abstract Glaucous Gulls (Larus hyperboreus) nesting on the Yukon-Kuskokwim (Y-K) Delta frequently prey on juvenile waterfowl. We collected 434 Glaucous Gulls from late June to early August 1994 to examine diet. Identification of undigested prey tissue, based on DNA microsatellite loci, showed three species of goslings in gull stomachs: Emperor Goose (Chen canagica), White-fronted Goose (Anser albifrons), and Cackling Canada Goose (Branta canadensis minima). Gulls that nested inland and were collected >1.6 km from the coast accounted for approximately 70% of the total gull predation on Emperor and Canada Geese, and 96% on White-fronted Geese. Our stratified sample of gull stomachs and aerial survey estimates of population size and distribution of gulls and juvenile geese enabled extrapolation of species-specific predation rates to the entire Y-K Delta. We estimated that a minimum of 21 000 Emperor Goose, 34 000 Canada Goose, and 16 000 White- fronted Goose goslings were consumed by 12 600 Glaucous Gulls du...

Organotins in marine mammals and seabirds from Norwegian territory.

An increasing number of studies indicate that marine mammals and some seabirds are exposed to organotins. However, results from northern and Arctic areas are few. Here results from analysis of tributyltin (TBT), dibutyltin (DBT), monobutyltin (MBT), triphenyltin (TPhT), diphenyltin (DPhT) and monophenyltin (MPhT) in harbour porpoise (Phocoena phocoena), common seal (Phoca vitulina), ringed seal (Phoca hispida) and glaucous gull (Larus hyperboreus) from Norwegian territory are presented. Relatively high concentrations of DBT, TBT and MBT were observed in muscle, kidney and liver from harbour porpoises caught in northern Norway in 1988, just before restrictions on the use of tributyltin (TBT)(mainly on small boats) were introduced in several European countries. The concentrations in harbour porpoise muscle tissue were reduced significantly 11 years later, possibly as a result of the introduced restrictions. Considerably lower concentrations of butyltins were observed in the seals compared to porpoises. The lowest levels of organotins were found in ringed seals from Spitsbergen, where only traces of dibutyltin (DBT) and monobutyltin (MBT) were observed. Traces of DBT and MBT were also found in some individual glaucous gulls from Bear Island. The sum of the degradation products MBT and DBT in liver samples from all analysed species were generally higher than TBT itself. Triphenyltin (TPhT) was observed in all porpoise samples and in livers of common seals. Also the sum of the degradation products MPhT and DPhT in liver samples from porpoise and common seals were higher than TPhT. No traces of phenyltins were found in ringed seals from Spitsbergen or in glaucous gulls from Bear Island. The limited data available indicate low to moderate exposure to organotins in northern areas (Spitsbergen and Bear Island). Marine mammals are however more exposed further south along the Norwegian Coast.

Age and accumulation of persistent organochlorines: a study of Arctic-breeding glaucous gulls (Larus hyperboreus).

We studied the relationship between increasing age and blood concentrations of four persistent organochlorines (OCs), hexachlorbenzene (HCB), oxychlordane, p,p'-dichlorodiphenyldichloroethylene (DDE), and 2,2',4,4',5,5'-hexachlorbiphenyl (PCB-153), in arctic-breeding glaucous gulls (Larus hyperboreus). We measured OC concentrations in 31 individuals of known age and took repeated blood samples of 64 individuals in different years, either one year apart or three or four years apart. The age of individuals was not related to the blood concentrations for any of the four compounds, and in birds whose values were measured repeatedly, there was no effect of the length of time (number of years) between sampling events on the relative change in OC concentration. This indicates that steady-state levels were reached before the age of first breeding. However, breeding area significantly influenced the changes in OC concentration between sampling events. In areas in which birds fed on prey from higher trophic levels, the OC concentrations showed large increases between sampling events; in areas in which birds fed at lower trophic levels, OC concentrations increased relatively little or not at all. This indicates that individual birds had different equilibrium concentrations, which are reached at different ages depending on the intake of OCs through the food. It also indicates that some individuals had not reached steady-state concentrations at the onset of reproduction. Changes in body condition and amount of blood lipids were of lesser importance than trophic level and influenced the concentrations of HCB and oxychlordane more strongly than DDE and PCB-153. In conclusion, this study indicates that steady-state concentrations of persistent OCs are reached early in life in most glaucous gulls, considering the long life span of the species.

Blood concentration of organochlorine pollutants and wing feather asymmetry in Glaucous Gulls

SummaryNon‐directional asymmetries (fluctuating asymmetry, FA) from bilateral symmetry in morphological traits have been used as an indicator of environmental stress and may become an important diagnostic tool in environmental sciences, such as ecotoxicology.In this study the relationship was examined between wing feather asymmetry, measured as the difference between the length of the third primary on the left and right wing, and blood concentration of selected persistent organochlorines (OCs) in Arctic breeding Glaucous Gulls (Larus hyperboreus, Gunnerus).There was a positive relationship between primary asymmetry and blood concentrations of two PCB (polychlorinated biphenyl) congeners (P &lt; 0·05), oxychlordane (P &lt; 0·05), DDE (p′p′‐dichlorodiphenyldichloroethylene) (P &lt; 0·05), and especially HCB (hexachlorbenzene) (P &lt; 0·001). At HCB levels above 30 ng g−1(wet mass) there was a 60% probability that the birds had asymmetric wing feathers.This study indicated that the present levels of organochlorines in the European Arctic are stressors for Glaucous Gulls, and that asymmetry measurements of wing feathers may be used as an indicator of both exposure and effects of such contaminants. FA may also be a promising measurement for monitoring the early effects of organochlorine pollution on bird populations.

Polychlorinated camphenes (toxaphenes), polybrominated diphenylethers and other halogenated organic pollutants in glaucous gull ( Larus hyperboreus) from Svalbard and Bjørnøya (Bear Island)

The levels of polychlorinated camphenes (toxaphenes) were investigated in liver samples from 18 glaucous gulls ( Larus hyperboreus) from Bjørnøya (74°N, 19°E) and four individuals from Longyearbyen (78°N, 15°E). Additionally brominated flame retardants (BFRs), PCBs and chlorinated pesticides were investigated in liver and intestinal contents of 15 of the glaucous gulls from Bjørnøya. Of the analysed BFRs only 2,2′,4,4′-tetra- and 2,2′,4,4′,5-pentabrominated diphenylethers (PBDE 47 and 99) could be detected. The concentrations ranged between 2 and 25 ng/g ww. In addition, high resolution measurements with GC/HRMS revealed the existence of several, not quantified, PBDEs and polybrominated biphenyls (PBBs) congeners in the samples. B9-1679 and B8-1413 were the dominating toxaphenes with median concentrations of 8 and 15 ng/g ww. Concentrations of toxaphenes and PBDEs were up to 100-times lower than the concentrations of PCB and some of the pesticides. PCB and p,p′-DDE constituted 90% of the contaminants found.

Intraspecific variation in trophic feeding levels and organochlorine concentrations in glaucous gulls (Larus hyperboreus) from Bjørnøya, the Barents Sea.

Biomagnification contributes to high concentrations of persistent organochlorines (OC) in some Arctic vertebrates. Glaucous gulls (Larus hyperboreus) on Bjørnøya in the western Barents Sea were studied to compare the intraspecific variation in OC concentration with variation in trophic feeding levels, estimated from ratios of nitrogen isotopes. Liver tissue samples from 40 adult glaucous gulls were analysed for hexachlorobenzene (HCB), oxychlordane, p,p'-dichlorodiphenyltrichloroethane (DDT) and its metabolite p,p'-DDE, Mirex, and nine congeners of polychlorinated biphenyl (PCB). The ratios of the heavier to lighter isotope of carbon (13C/12C) and nitrogen (15N/14N), expressed as delta13C and delta15N, were measured in liver and muscle. Hepatic concentrations of the nine PCB congeners (Sigma 9 PCB) ranged from 16 microg/g lipid weight to 292 microg/g lipid weight. The delta15N ranged from 14.0/1000 to 15.3/1000 in muscle. Seven of the 14 OC measured, sigma DDT, and sigma 9 PCB were positively correlated to delta15N from muscle tissue. No correlations were found between OC and delta13C. The present results indicate that OC concentrations are partly dependent on the foraging strategy of the gull. The r2 of the linear regressions suggests that up to 18% of the variation in the OC concentrations could be explained by variation in food preference.

A stable isotope (δ13C, δ15N) model for the North Water food web: implications for evaluating trophodynamics and the flow of energy and contaminants

The North Water Polynya is an area of high biological activity that supports large numbers of higher trophic-level organisms such as seabirds and marine mammals. An overall objective of the Upper Trophic-Level Group of the International North Water Polynya Study (NOW) was to evaluate carbon and contaminant flux through these high trophic-level (TL) consumers. Crucial to an evaluation of the role of such consumers, however, was the establishment of primary trophic linkages within the North Water food web. We used δ15N values of food web components from particulate organic matter (POM) through polar bears (Ursus maritimus) to create a trophic-level model based on the assumptions that Calanus hyperboreus occupies TL 2.0 and there is a 2.4‰ trophic enrichment in 15N between birds and their diets, and a 3.8‰ trophic enrichment for all other components. This model placed the planktivorous dovekie (Alle alle) at TL 3.3, ringed seal (Phoca hispida) at TL 4.5, and polar bear at TL 5.5. The copepods C. hyperboreus, Chiridius glacialis and Euchaeta glacialis formed a trophic continuum (TL 2.0–3.0) from primary herbivore through omnivore to primary carnivore. Invertebrates were generally sorted according to planktonic, benthic and epibenthic feeding groups. Seabirds formed three trophic groups, with dovekie occupying the lowest, black-legged kittiwake (Rissa tridactyla), northern fulmar (Fulmarus glacialis), thick-billed murre (Uria aalge), and ivory gull (Pagophilia eburnea) intermediate (TL 3.9–4.0), and glaucous gull (Larus hyperboreus) the highest (TL 4.6) trophic positions. Among marine mammals, walrus (Odobenus rosmarus) occupied the lowest (TL 3.2) and bearded seal (Erignathus barbatus), ringed seal, beluga whale (Delphinapterus leucas), and narwhal (Monodon monoceros) intermediate positions (TL 4.1–4.6). In addition to arctic cod (Boreogadus saida), we suggest that lower trophic-level prey, in particular the amphipod Themisto libellula, contribute fundamentally in transferring energy and carbon flux to higher trophic-level seabirds and marine mammals. We measured PCB 153 among selected organisms to investigate the behavior of bioaccumulating contaminants within the food web. Our isotopic model confirmed the trophic magnification of PCB 153 in this high-Arctic food web due to a strong correlation between contaminant concentration and organism δ15N values, demonstrating the utility of combining isotopic and contaminant approaches to food-web studies. Stable-carbon isotope analysis confirmed an enrichment in 13C between POM and ice algae (–22.3 vs. –17.7‰). Benthic organisms were generally enriched in 13C compared to pelagic species. We discuss individual species isotopic data and the general utility of our stable isotope model for defining carbon flux and contaminant flow through the North Water food web.