Levels and pattern of polybrominated diphenyl ethers in eggs of Antarctic seabirds: Endemic versus migratory species

Chinstrap and gentoo penguins are endemic species that live year round south of the Antarctic Convergence. South polar skua is a migratory seabird that can be observed in Antarctica during the breeding season (i.e., austral summer). This study compares concentration and pattern of polybrominated diphenyl ethers (PBDEs) in eggs of seabirds breeding at King George Island, Antarctic Peninsula. PBDEs in south polar skua eggs are approximately 20 times higher than in penguin eggs suggesting that skuas are more exposed to contaminants during the non-breeding season when they migrate to waters of the northern hemisphere. The pattern of PBDE congeners also differs between south polar skua and penguin eggs. The latter exhibited a pattern similar to that found in the local biota. In contrast, the congener pattern in south polar skua eggs suggests that birds breeding at King George Island may winter in the northwestern Pacific Ocean.     

Use of a food web model to evaluate the factors responsible for high PCB fish concentrations in Lake Ellasjøen, a high Arctic Lake

Background, aim, and scope

Lake Ellasjøen, located in the Norwegian high arctic, contains the highest concentrations of polychlorinated biphenyls (PCBs) ever recorded in fish and sediment from high arctic lakes, and concentrations are more than 10 times greater than in nearby Lake Øyangen. These elevated concentrations in Ellasjøen have been previously attributed, in part, to contaminant loadings from seabirds that use Ellasjøen, but not Øyangen, as a resting area. However, other factors, such as food web structure, organism growth rate, weight, lipid content, lake morphology, and nutrient inputs from the seabird guano, also differ between the two systems. The aim of this study is to evaluate the relative influence of these factors as explanatory variables for the higher PCB fish concentrations in Ellasjøen compared with Øyangen, using both a food web model and empirical data.

Methods

The model is based on previously developed models but parameterized for Lakes Ellasjøen and Øyangen using measured data wherever possible. The model was applied to five representative PCB congeners (PCB 105, 118, 138, 153, and 180) using measured sediment and water concentrations as input data and evaluated with previously collected food web data.

Results

Modeled concentrations are within a factor of two of measured concentrations in 60% and 40% of the cases in Lakes Ellasjøen and Øyangen, respectively, and within a factor of 10 in 100% of the cases in both lakes. In many cases, this is comparable to the variability associated with the data as well as the efficacy of the predictions of other food web model applications.

Discussion

We next used the model to quantify the relative importance of five major differences between Ellasjøen and Øyangen by replacing variables representing each of these factors in the Ellasjøen model with those from Øyangen, in separate simulations. The model predicts that the elevated PCB concentrations in Ellasjøen water and sediment account for 49%–58% of differences in modeled fish PCB concentrations between lakes. These elevated sediment and, to a lesser extent, water concentrations in Ellasjøen are due to PCB loadings from seabird guano. However, sediment–water fugacity ratios of PCBs are consistently greater in Ellasjøen compared with Øyangen, which suggests that internal lake processes also contribute to differences in sediment and water concentrations. We hypothesize that the nutrients associated with guano influence sediment–water fugacity ratios of PCBs by increasing the stock of pelagic algae. As both these algae and the guano settle, their organic carbon content is degraded faster than PCBs, which causes an extra magnification step in Ellasjøen before these detrital particles are consumed by benthic organisms, which are in turn consumed by fish. The model predicts that the remaining ～50% of the differences in PCB concentrations observed between the fish of these lakes are due to other subtle differences in their food web structures.

Conclusions

In conclusion, based on the results of a food web model, we found that the most dominant factors influencing the higher PCB fish concentrations in Lake Ellasjøen compared with Øyangen are the higher sediment and water concentrations in Ellasjøen, caused by seabird guano. Together, sediment and water are predicted to account for 49%–58% of differences in fish concentrations between lakes. Although seabird guano provides a source of nutrients to the lake, in addition to contaminants, empirical data and indirect model results suggest that nutrients are not leading to decreased bioaccumulation, in contrast to what has been observed in temperate, pelagic food webs.

Recommendations and perspectives

The results of this study emphasize the importance of considering even small differences in food web structure when comparing bioaccumulation in two lakes; although the food web structures of Ellasjøen and Øyangen differ only slightly, the model predicts that these differences account for most of the remaining ～50% of the differences in PCB fish concentrations between the two lakes. This study further demonstrates the utility of food web models as we were able to predict and tease apart the influence of various factors responsible for the elevated concentrations in the fish from Lake Ellasjøen, which would have been difficult using the field data alone.     

A 50-year record of dichloro-diphenyl-trichloroethanes and hexachloro-cyclohexanes in lake sediments and penguin droppings on King George Island, Maritime Antarctic

Since the ban on the use of organochlorine pesticides （OCPs） such as dichloro-diphenyl-trichloroethane （DDT） and hexachlorocyclohexane（HCH） in agriculture, their levels have generally dropped. In a number of cases, however, the levels of these OCPs were found to be unchanging or even increasing after the ban. With the aim to unveil the possible causes of these exceptions, we collected two lake cores from King George Island, West Antarctica, and determined their accumulation flux profiles and temporal trends of these OCPs. In the lake core sediments with glacier meltwater input, the accumulation flux of DDT shows an abnormal peak around 1980s in addition to the expected one in 1960s. In the lake core sediments without glacier meltwater input, the accumulation flux of DDT shows a gradual decline trend after the peak in 1960s. This striking difference in the DDT flux profiles between the two lake cores is most likely caused by the regional climate warming and the resulted discharge of the DDT stored in the Antarctic ice cap into the lakes in the Antarctic glacier frontier. Furthermore, to investigate the change of OCPs loadings in the Antarctic coastal ecosystem, we reconstructed the HCH and DDT concentration profiles in penguin droppings and observed a gradual increase for the former and a continuous decrease for the latter during the past 50 years. The increase of HCH seems to be due to the regional warming from the early 1970s and the resulted HCH discharge to the coastal ecosystem by glaciers＇ meltwater and the illegal use of HCH in the Southern Hemisphere in the recent decade. The different temporal trends of HCH and DDT accumulation rate in the lake core with glacier meltwater input and the aged penguin droppings can be explained by their different water-soluble property.     

Fluoride Content in Bones of Adelie Penguins and Environmental Media in Antarctica

Fluoride (F) distribution and its effects (fluorosis) were investigated in Antarctica. Droppings (L) excreta selected of aquatic birds, lake water, soil and moss (Polytrichum alpinum) showed a high F concentration. Although bones of Adelie penguin (Pygiscelis adeliae) and skua (Catharacta maccormicki) showed exceptionally very high F concentration in the range of 832 to 7187 mg kg(-1), their radiographs did not show any evidence of skeletal fluorosis. The possible reason and geochemical aspects of F in Antarctica region are discussed.     

以鸟粪石的形式在污水处理厂回收磷的研究

磷既是一种不可再生的资源,也是造成水体富营养化的重要因素。近年来,随着磷资源的匮乏,从污水处理厂回收磷在世界各国逐渐兴起,而我国在这方面的研究还基本处于起始阶段。为此,在某污水处理厂进行了以鸟粪石形式回收磷的小试实验,考察了磷回收的一些控制参数,并将以此作为基础,继续深入研究。     

Stimulation of gaseous phosphine production from Antarctic seabird guanos and ornithogenic soils

Matrix-bound phosphine (MBP) is a general term used to indicate non-gaseous reduced phosphorus compounds that are transformed into phosphine gas upon reaction with bases or acids. Antarctic seabird guanos and ornithogenic soils were used as materials to compare the different digestion methods for transforming matrix-bound phosphine into phosphine gas. The results demonstrated that more phosphine gas in most of Antarctic environmental materials was formed of matrix-bound phosphine by caustic digestion than by acidic digestion. The comparative study on different digestion methods also revealed that the fraction of MBP converted to gaseous phosphine during the digestion depended on the temperature. The optimal digestion temperature was close to 70℃ and the optimal digestion time was about 20 min. Acidic conditions were more favorable for the release of matrix-bound phosphine compared to the central[u1] conditions. The proper additional water dilution can increase the production and emission of phosphine from the Antarctic penguin guanos.     

南极企鹅粪土地层、机体组织与卵中POPs含量分布及其生态环境意义

对南极阿德雷岛企鹅栖息地粪土混合地层进行210Pb定年,同时采用气相色谱－电子捕获检测器 (GC－ECD)内标定量法测定了企鹅栖息地粪土混合地层及其机体组织中的有机氯污染物分布.结果表明:粪土混合地层中表层的有机氯污染物含量最高,w(PCBs),w(HCHs)和w(DDTs)分别为0.92,0.42和0.70 ng/g. 与非栖息地的比较表明,通过有鸟类活动的粪土混合地层(营巢和粪便)输入的PCBs和OCPs比无鸟类生命途径的高. 因此,海鸟成为将有机氯污染物带到南极大陆的媒介和途径. 有机氯污染物主要分布在企鹅机体的脂质和脂肪中,其中脂肪和尾臀腺中的含量最高,脂肪中w(PCBs),w(HCB),w(HCHs) 和w(DDTs)分别为126.9～277.0,43.2～197.0, 未检出～20.7 和79.4～110.1 ng/g. 蛋卵中w(PCBs), w(DDTs),w(HCB)和w(HCHs)分别为0.4～0.9,2.4～10.3,6.0～10.2和0.1～0.4 ng/g,总积蓄水平依次为HCB>DDTs>PCBs>HCHs. 对比PCBs在企鹅体内的积累与排出(粪土和产卵)过程可知,前者占主导地位.在南极企鹅机体组织和卵中检出PCBs和OCPs表明,有机氯农药可在鸟类动物体内积累与代间转移,在相当长的时期内难以消除.      

Carotenoid-derived ornaments reflect parental quality in male and female yellow-eyed penguins (<Emphasis Type="Italic">Megadyptes antipodes</Emphasis>)

The handicap principle suggests that ornamental traits that function as honest signals in mate selection must be costly to be effective. We evaluated in the sexually monochromatic yellow-eyed penguin (Megadyptes antipodes) whether the carotenoid-derived plumage and eye coloration predicts parental quality and whether males and females within pairs mate assortatively in relation to these carotenoid-derived ornaments. In addition, we investigated whether age or body condition was related to the coloration of the ornamental traits. In yellow-eyed penguins, parental quality of males and females was predicted by eye and head plumage coloration. Even when we controlled for gender- and age-specific differences, eye and head plumage coloration reflected honestly parental quality. Males and females mated assortatively in relation to these ornamental traits. While age influenced coloration of both the eye and head plumage, body condition was related only to the saturation of plumage coloration. These results provide evidence that the carotenoid-derived ornaments in yellow-eyed penguins reflect the parental abilities of birds and, therefore, may be costly signals. Potentially, female and male yellow-eyed penguins could use eye and plumage coloration as an indirect cue in assessing age and quality of individual birds during mate choice. This is only the second study to examine plumage coloration in relation to sexual selection in penguins, while conspicuous ornamental traits in other species of penguin beg the question whether they also play a role in sexual selection.Electronic Supplementary Material Supplementary material is available in the online version of this article at Communicated by C.R. Brown     

浅议污水厂的磷回收

为控制水体富营养化 ,城市污水处理厂采用生物除磷脱氮工艺 ,因此在某些处理单元中有富磷液流产生。根据乌粪石生成的原理 ,在富磷液流中投加镁源 ,并调节pH为 8 5～ 9 0时 ,即能以乌粪石形式回收磷以补充日益短缺的磷资源。     

Antarctic krill fishery effects over penguin populations under adverse climate conditions: Implications for the management of fishing practices

Fast climate changes in the western Antarctic Peninsula are reducing krill density, which along with increased fishing activities in recent decades, may have had synergistic effects on penguin populations. We tested that assumption by crossing data on fishing activities and Southern Annular Mode (an indicator of climate change in Antarctica) with penguin population data. Increases in fishing catch during the non-breeding period were likely to result in impacts on both chinstrap (Pygoscelis antarcticus) and gentoo (P. papua) populations. Catches and climate change together elevated the probability of negative population growth rates: very high fishing catch on years with warm winters and low sea ice (associated with negative Southern Annular Mode values) implied a decrease in population size in the following year. The current management of krill fishery in the Southern Ocean takes into account an arbitrary and fixed catch limit that does not reflect the variability of the krill population under effects of climate change, therefore affecting penguin populations when the environmental conditions were not favorable.Electronic supplementary materialThe online version of this article (10.1007/s13280-020-01386-w) contains supplementary material, which is available to authorized users.