Trace and rare earth elements in excreta of two species of marine mammals from South Shetland Islands, Antarctica

Seabird transported contaminants are dispersed in island ecosystems

Seabirds are long-range transporters of nutrients and contaminants, linking marine feeding areas with terrestrial breeding and roosting sites. By depositing nutrient-rich guano, which acts as a fertiliser, seabirds can substantially influence the terrestrial environment in which they reside. However, increasing pollution of the marine environment has resulted in guano becoming similarly polluted. Here, we determined metal and metalloid concentrations (As, Cd, Cr, Cu, Hg, Pb) in Flesh-footed Shearwater (Ardenna carneipes) guano, soil, terrestrial flora, and primary consumers and used an ecological approach to assess whether the trace elements in guano were bioaccumulating and contaminating the surrounding environment. Concentrations in guano were higher than those of other Procellariiformes documented in the literature, which may be influenced by the high amounts of plastics that this species of shearwater ingests. Soil samples from shearwater colonies had significantly higher concentrations of all metals, except for Pb, than soils from control sites and formerly occupied areas. Concentrations in terrestrial primary producers and primary consumers were not as marked, and for many contaminants there was no significant difference observed across levels of ornithogenic input. We conclude that Flesh-footed Shearwaters are transporters of marine derived contaminants to the Lord Howe Island terrestrial environment.

Distribution of rare earth elements (REEs) in the feathers of gentoo penguins (Pygoscelis papua) from different geographical locations of the Antarctic peninsula area

Antarctica is the most remote and coldest regions of the planet, but the presence of REEs there has received little attention. This study assessed REE-contents in the feathers of adult gentoo penguins from Ardley Island, Kopaitic Island and Base O'Higgins. Field work was accomplished during 2011 (austral summer), and determination of elements was performed with ICP-MS. In general, REE-levels showed descending relations as follows: Ce > La > Y > Nd > Sc > Pr > Gd > Sm > Dy >Er > Yb > Eu > Ho > Tb > Tm > Lu. The data showed an increase of the levels of REEs from the lower part of the feather to the tip. This finding seems to be spatially dependent, but geochemical, anthropogenic conditions, feeding habits, sex, or even health status of birds should also be considered. It is a subject that requires deeper attention in future studies.

Foraging behavior and age affect maternal transfer of mercury to northern elephant seal pups

Deep ocean foraging northern elephant seals (Mirounga angustirostris) consume fish and squid in remote depths of the North Pacific Ocean. Contaminants bioaccumulated from prey are subsequently transferred by adult females to pups during gestation and lactation, linking pups to mercury contamination in mesopelagic food webs (200-1000 m depths). Maternal transfer of mercury to developing seal pups was related to maternal mercury contamination and was strongly correlated with maternal foraging behavior (biotelemetry and isotopes). Mercury concentrations in lanugo (hair grown in utero) were among the highest observed worldwide for young pinnipeds (geometric mean 23.01 μg/g dw, range 8.03-63.09 μg/g dw; n = 373); thus, some pups may be at an elevated risk of sub-lethal adverse health effects. Fetal mercury exposure was affected by maternal foraging geographic location and depth; mercury concentrations were highest in pups of the deepest diving, pelagic females. Moreover, pup lanugo mercury concentrations were strongly repeatable among successive pups of individual females, demonstrating relative consistency in pup mercury exposure based on maternal foraging strategies. Northern elephant seals are biosentinels of a remote deep-sea ecosystem. Our results suggest that mercury within North Pacific mesopelagic food webs may also pose an elevated risk to other mesopelagic-foraging predators and their offspring.

Concentration of fifty-six elements in excreta of penguins from the Antarctic Peninsula area

Seabird feces as indicators of the exposure to environmental contaminants have been studied worldwide. Penguins are indicator species for marine pollution, but their role as biovectors of rare earth elements (REEs) to ecosystems have been little studied. The present study quantified the concentration of REEs and trace elements (TEs) in feces of gentoo penguin (Pygoscelis papua). Adult penguin excreta from Fildes Bay (King George Island) and Yelcho Base (Palmer Archipelago) were collected and then analyzed by ICP-MS. Among REEs, levels ranged from 0.0038 to 1.02 μg g^-1 d.w. for Lu and Ce, respectively. For TEs, the levels varied widely through the sample set, with Al, Fe, Sr, Zn and Ti as the highest mean levels, particularly at Fildes Bay. The data show that gentoo penguins act as a biovector organism by transporting TEs and REEs from the sea to land via excreta, reaffirming that this species acts as an important biovector organism in Antarctic ecosystems. The potential impacts of this process on Antarctic ecosystems needs further research.