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The Nitrogen Pathway in a Penguin Rookery
Ecology, 65 (1): 269--277 (1984)
Аннотация
The most important nitrogen sources for the Marion Island ecosystem are the excreta of birds that forage at sea. Eighty percent of the nitrogen excreted by penguins during their molt fast appeared to be uric acid, with the remaining 20\% mainly proteins and ammonia. The uric acid is rapidly degraded by aerobic and anaerobic microorganisms, and no uric acid could be detected in the penguin rookery deposit. Nitrification, followed by denitrification, occurs in the rookery deposit. However, laboratory experiments showed that both nitrification and denitrification are relatively unimportant processes in the rookery. Models of the nitrogen cycle in both a Macaroni Penguin and a King Penguin rookery during the molt fast and breeding season are given. In both rookeries the degradation of uric acid into ammonia and the subsequent evaporation are, quantitatively, the most important processes. The ammonia production in the rookeries of Macaroni Penguins as well as the heavy rains and the predominantly westerly winds have produced an @'ammonia shadow@' around the rookery where a vigorous plant growth occurs. The vegetation has formed a thick peat layer around the penguin rookery. ^1^4C dating of this peat layer has shown that the Macaroni Penguins first bred on Marion Island @?7000 yr ago.
