Premium
Microbial functional diversity alters the structure and sensitivity of oxygen deficient zones
Author(s) -
Penn Justin,
Weber Thomas,
Deutsch Curtis
Publication year - 2016
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2016gl070438
Subject(s) - denitrification , anammox , ecosystem , environmental science , heterotroph , nitrification , environmental chemistry , microbial population biology , community structure , ecology , nitrogen cycle , atmospheric sciences , nitrogen , chemistry , biology , geology , organic chemistry , bacteria , genetics , denitrifying bacteria
Oxygen deficient zones (ODZs) below the ocean surface regulate marine productivity by removing bioavailable nitrogen (N). A complex microbial community mediates N loss, but the interplay of its diverse metabolisms is poorly understood. We present an ecosystem model of the North Pacific ODZ that reproduces observed chemical distributions yet predicts different ODZ structure, rates, and climatic sensitivity compared to traditional geochemical models. An emergent lower O 2 limit for aerobic nitrification lies below the upper O 2 threshold for anaerobic denitrification, creating a zone of microbial coexistence that causes a larger ODZ but slower total rates of N loss. The O 2 ‐dependent competition for the intermediate nitrite produces gradients in its oxidation versus reduction, anammox versus heterotrophic denitrification, and the net ecological stoichiometry of N loss. The latter effect implies that an externally driven ODZ expansion should favor communities that more efficiently remove N, increasing the sensitivity of the N cycle to climate change.