Penguins, returning from the open ocean after feeding, deposit marine-based nutrients on Antarctic terrestrial ecosystems, which may subsequently run-off into nearshore waters due to snowmelt. Any changes in penguin densities or diversity, due to human disturbance or climate change, may alter nutrient inputs to these environments and thus alter the trophic balance of the Antarctic marine and terrestrial ecosystems. The focus of the study was to examine the relationship between penguin colony densities and the concentration of nutrients and primary producers in Antarctic peninsular sites commonly visited by tourists. Eight sites in the South Shetland Islands and Antarctic Peninsula were visited in December 2007.  The number of nesting pairs of penguins was estimated from prior surveys. Concentrations of marine algal biomass, water nutrients, terrestrial plant cover and diversity, microarthropod abundance and soil nutrients were assessed at each site.

Results/Conclusions

Water column nutrients, including total phosphorus and ammonia, and algal biomass as estimated by chlorophyll-a, increased significantly with the total number of penguin pairs in colonies. Similarly, terrestrial plant cover and Collembola abundance was significantly higher at sites with higher penguin densities. These results not only have implications for understanding the impact of changes in penguin densities due to tourism in Antarctica, but may also serve to indicate any food web impacts due to changes in penguin distributions due to climate change in the region.