We carried out a study to investigate the presence of some protozoan parasites (Cryptosporidium sp., Giardia sp., Toxoplasma gondii) on three species of Antarctic penguins: Adélie (Pygoscelis adeliae), gentoo (Pygoscelis papua) and chinstrap (Pygoscelis antarctica) from different locations along the Antarctic Peninsula and the South Shetland Islands. Swabs and faeces samples were analysed by PCR assay for Cryptosporidium sp. and Giardia sp. while Toxoplasma was studied using serological methods from blood samples. We did not detect the presence of these organisms in the species studied. However, based on the upper values of the confidence intervals of the observed prevalence, their presence cannot be completely excluded.

Several sub-Antarctic penguin populations have exhibited decreasing trends in the last 5–20 years. At Iles Kerguelen, the gentoo penguin (Pygoscelis papua) has decreased by approximately 30% over the last 15 years. This decrease is likely to be related to reduced food availability for this coastal species. We discuss this decrease with regard to the impact of overfishing and to the potential effects of climate changes on marine food webs.

Gentoo penguin Pygoscelis papua is an important component of the Antarctic marine ecosystem. In this paper, we use an indirect approach, a geochemical method combining with 137Cs and 210Pb CRS mode dating, to study the dynamics of the gentoo population and colony on Barton Peninsula, King George Island, in the maritime Antarctic. Five sediment profiles were sampled in the zone between the gentoo penguin colony and tundra vegetation on this peninsula and the sediment sequence and typical elements from penguin guano were analysed. Results showed that the levels for typical elements display a dramatic change at around 5 cm depth, indicating the strong impact of penguin guano. The sediments below 5 cm showed lower concentrations in these elements, suggesting that these sediments had received little impact from penguin guano. By Q-mode factor analysis, a method for decomposing multiple factors, we found that over the past sixty years the gentoo colony showed a rapid enlargement and the tundra vegetation had been destroyed. Possible factors responsible for the enlargement of the penguin colony are tentatively discussed.