Seabird colonies as relevant sources of pollutants in Antarctic ecosystems: Part 2 - Persistent Organic Pollutants

International audienceDespite typically not being taken into account (usually in favour of the "Global Distillation" process), the input of Persistent Organic Pollutants (POPs) via biological activity can be indeed relevant at the local scale in terrestrial Polar environments when seabird colonies are considered. The fact that seabirds bioaccumulate and biomagnify those POPs, gather in large numbers and excrete on land during their reproductive season can act locally as relevant secondary source of the same contaminants. The first part of this study indicated that these colonies act as so for several essential and non-essential trace elements and this second part tests the same hypothesis concerning POPs using the very same samples. Lichens (n=55), mosses (n=58) and soil (n=37) were collected in 13 locations within the South Shetlands Archipelago during the austral summers of 2013-14 and 2014-15. They were divided in colony (within the colony itself for soil and bordering it for vegetation) and control (at least 150m away from any colony interference), analysed for POPs: organochlorine pesticides, polychlorinated byphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs); and stable isotopes (C and N). Results showed that colonies act clearly as a secondary source for PCBs and likely for HCB. As in the first part, probable local sources other than the colonies themselves are hypothesised due to high concentrations found in control sites. Again, soil seemed the most adequate matrix for the intended purposes especially because of some particularities in the absorption of animal derived organic matter by vegetation, pointed out by stable isotope analyses

Projected distributions of Southern Ocean albatrosses, petrels and fisheries as a consequence of climatic change

Given the major ongoing influence of environmental change on the oceans, there is a need to understand and predict the future distributions of marine species in order to plan appropriate mitigation to conserve vulnerable species and ecosystems. In this study we use tracking data from seven large seabird species of the Southern Ocean (black-browed albatross Thalassarche melanophris, grey-headed albatross T. chrysostoma, northern giant petrel Macronectes halli, southern giant petrel M. giganteus, Tristan albatross Diomedea dabbenena, wandering albatross D. exulans and white-chinned petrel Procellaria aequinoctialis, and on fishing effort in two types of fisheries (characterised by low or high-bycatch rates), to model the associations with environmental variables (bathymetry, chlorophyll-a concentration, sea surface temperature and wind speed) through ensemble species distribution models. We then projected these distributions according to four climate change scenarios built by the Intergovernmental Panel for Climate Change for 2050 and 2100. The resulting projections were consistent across scenarios, indicating that there is a strong likelihood of poleward shifts in distribution of seabirds, and several range contractions (resulting from a shift in the northern, but no change in the southern limit of the range in four species). Current trends for southerly shifts in fisheries distributions are also set to continue under these climate change scenarios at least until 2100; some of these may reflect habitat loss for target species that are already over-fished. It is of particular concern that a shift in the distribution of several highly threatened seabird species would increase their overlap with fisheries where there is a high-bycatch risk. Under such scenarios, the associated shifts in distribution of seabirds and increases in bycatch risk will require much-improved fisheries management in these sensitive areas to minimise impacts on populations in decline

Seabird colonies as relevant sources of pollutants in Antarctic ecosystems: Part 1 - Trace elements

International audienceGlobal distillation is classically pointed as the biggest responsible for contaminant inputs in Polar ecosystems. Mercury (Hg) and other trace elements (TEs) also present natural sources, whereas the biologically mediated input is typically ignored. However, bioaccumulation and biomagnification combined with the fact that seabirds gather in large numbers into large colonies and excrete on land might represent an important local TEs input. A previous work suggested these colonies as sources of not only nutrients, but also organic contaminants. To evaluate a similar hypothesis for TEs, samples of lichen (n = 55), mosses (n = 58) and soil (n = 37) were collected in 13 locations within the South Shetlands Archipelago during the austral summers of 2013-14 and 2014-15. They were divided in: "colony" (within the colony itself for soil and bordering it for vegetation) and "control" (at least 50m away from colony interference), analysed for TEs (As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, V, and Zn) and stable isotopes (C and N). In most cases, soil seems the best matrix to assess colonies as TEs sources, as it presented more differences between control/colony sites than vegetation. Colonies are clearly local sources of organic matter, Cd, Hg and likely of As, Se and Zn. Conversely, Co, Cr, Ni and Pb come presumably from other sources, natural or anthropogenic. In general, isotopes were more useful for interpreting vegetation data due to fractionation of absorbed animal-derived organic matter. Other local Hg sources could be inferred from high levels in control sites, location and wind patterns

Surviving probability indicators of landing juvenile magellanic penguins arriving along the southern brazilian coast

The aim of this work was to monitor and study the hematocrit and weight of juvenile penguins, with and without oil cover, found alive along the southern coast of Brazil, after capture, as well as before eventual death or release Released juvenile penguins showed higher weight and hematocrit (3.65 ± 0.06 kg and 44.63 ± 0.29%, respectively) than those that died (2.88 ± 0.08 kg and 34.42 ± 1.70%, respectively). Penguins with higher hematocrit and weigh after capture had higher mean weight gain than their counterparts with smaller hematocrit and weight after the capture. Besides, juveniles with higher hematocrit and weight after the capture had higher survival rates, independent of the presence or absence of oil. The results suggested that juveniles covered with oil might have been healthier than the juveniles without oil. The animals without oil probably died as a consequence of health disturbances, while the animals with oil possibly were healthy before contact with oil in the sea