Nitrous oxide emissions from sea animal colonies in the maritime Antarctic

[1] Little is known about nitrous oxide (N2O) emissions from wild animal colonies. N2O fluxes were measured from a penguin colony on Ardley Island, a seal and skua colony on Fildes Peninsula in the maritime Antarctic using a static chamber technique. Mean fluxes from penguin, skua and seal colonies were 856, 132 and 189 μg N2O-N m−2 h−1, respectively. The deposition of sea animal excreta controls spatial variations of N2O fluxes from the colonies. The highest fluxes (2559, 2836 and 2081 μg N2O-N m−2 h−1 for penguin puddles, seal wallows and skua puddles, respectively) occurred during the freezing-thawing period. Laboratory experiments showed that the freezing-thawing cycle induced a flush of N2O from the soils sampled from the colonies and denitrification was the predominant process for the N2O source. We proposed that sea animal colonies represent the strong point sources of N2O in the maritime Antarctic.