Microbial functional diversity alters the structure and sensitivity of oxygen deficient zones

Justin Penn, Thomas Weber, Curtis Deutsch

Research output: Contribution to journalArticlepeer-review

21 Scopus citations

Abstract

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 O2 limit for aerobic nitrification lies below the upper O2 threshold for anaerobic denitrification, creating a zone of microbial coexistence that causes a larger ODZ but slower total rates of N loss. The O2-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.

Original languageEnglish (US)
Pages (from-to)9773-9780
Number of pages8
JournalGeophysical Research Letters
Volume43
Issue number18
DOIs
StatePublished - Sep 28 2016
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Earth and Planetary Sciences(all)

Keywords

  • climate change
  • deoxygenation
  • ecological stoichiometry
  • microbial ecology
  • nitrogen cycle
  • oxygen minimum zones

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