Microbial ecology of expanding oxygen minimum zones

• Published in: Nature reviews. Microbiology 2012-06, Vol.10 (6), p.381-394
• Main Authors: Wright, Jody J., Konwar, Kishori M., Hallam, Steven J.
• Format: Article
• Language: English
• Subjects: 47; 631/326/2565; 631/326/2565/855; 631/553/1464; Biodiversity; Biogeochemistry; Biological diversity; Biomedical and Life Sciences; Biota; Carbon dioxide; Climate change; Dissolved oxygen; Ecology; Ecosystems; Emissions; Energy Metabolism; Greenhouse Effect; Greenhouse gases; Health sciences; Infectious Diseases; Life Sciences; Marine ecosystems; Medical Microbiology; Metabolism; Methane; Methane - metabolism; Microbiology; Nitrates; Nitrogen; Nitrous oxide; Nitrous Oxide - metabolism; Oxygen; Oxygen - metabolism; Parasitology; review-article; Seawater - microbiology; Stratigraphy; Trophic levels; Virology
• ISSN: 1740-1526; 1740-1534
• DOI: 10.1038/nrmicro2778

Key Points Oxygen minimum zones (OMZs) are oxygen-starved regions of the ocean that are currently expanding owing to the warming of the water column that is induced by global climate change. Although OMZs are inhospitable to aerobically respiring organisms, these regions support thriving microbial communities, the metabolic activities of which have a profound impact on marine productivity and climate balance. Plurality sequencing combined with process rate measurements and targeted gene surveys in coastal and open-ocean OMZs has identified conserved patterns of microbial community structure and function, and uncovered novel modes of metabolic integration coupling carbon, nitrogen and sulphur cycles. These findings have important implications for our understanding of the ecological and biogeochemical impacts of OMZ expansion. Co-occurrence networks built from taxonomic sequence data can help define putative metabolic interactions among the microorganisms in OMZs and can enable more direct hypothesis testing when combined with data concerning environmental parameters, process rates and functional genes. Determining how these networks form, function and change over time reveals links between microbial community structure and higher-order ecological and biogeochemical processes. This information has the potential to guide human adaptation and response in a time of climate change. Dissolved oxygen concentration is a crucial organizing principle in marine ecosystems. In this Review, Hallam and colleagues describe recent advances in our understanding of the ecological and microbial features of oxygen-starved regions of the ocean, known as oxygen minimum zones. Dissolved oxygen concentration is a crucial organizing principle in marine ecosystems. As oxygen levels decline, energy is increasingly diverted away from higher trophic levels into microbial metabolism, leading to loss of fixed nitrogen and to production of greenhouse gases, including nitrous oxide and methane. In this Review, we describe current efforts to explore the fundamental factors that control the ecological and microbial biodiversity in oxygen-starved regions of the ocean, termed oxygen minimum zones. We also discuss how recent advances in microbial ecology have provided information about the potential interactions in distributed co-occurrence and metabolic networks in oxygen minimum zones, and we provide new insights into coupled biogeochemical processes in the ocean.