Marine animals significantly increase tundra N 2 O and CH 4 emissions in maritime Antarctica

Most studies on greenhouse gas emissions from animals concentrated on domestic animals, with limited data available from wild animals. The number of marine animals is potentially large in coastal Antarctica. In this paper, N 2 O and CH 4 emissions were investigated from a penguin colony, a seal colony, a skua colony, the adjacent animal‐lacking tundra, and background tundra sites to test the effects of marine animals on their fluxes in maritime Antarctica. Extremely high N 2 O emissions occurred in the penguin puddles (mean 392 µg N 2 O m −2 h −1 ) and seal wallows (mean 579 µg N 2 O m −2 h −1 ). The N 2 O emissions from animal colony tundra (13–57 µg N 2 O m −2 h −1 ) are much higher than those from the animal‐lacking tundra, whereas the background tundra showed negligible N 2 O fluxes. Penguin puddles and seal wallows were stronger CH 4 emitters than animal colony tundra soils, while animal‐lacking tundra soils were strong CH 4 sinks. Overall high N 2 O and CH 4 emissions were modulated by soil physical and chemical processes associated with marine animal activities: sufficient supply of the nutrients NH 4 + –N and NO 3 − –N, total nitrogen, and total organic carbon from marine animal excreta, animal tramp, and high soil water‐filled pore space. Laboratory incubation experiments further confirmed that penguin and seal colony soils produced much higher N 2 O and CH 4 emissions than animal‐lacking tundra soils. Our results indicate that marine animal colonies are the hot spots for N 2 O and CH 4 emissions in maritime Antarctica, and even at the global scale, and current climate warming will further increase their emissions.