Insight
Nature Geoscience Insight - Marine cycles in flux
(Image credited to Photri Images / Alamy)
Microbes regulate the cycling of elements throughout the global ocean, from the icy surface waters that circulate at high latitudes, to the deep vents that dot the continental sea floor. Human activities are starting to modify the way in which microbes mediate these cycles, at least in the relatively well-characterized waters of the upper ocean. The deeper layers of the ocean are probably less affected, at least at present, and are definitely less well explored. However, technological advances are starting to shed light on the cycling of elements at depth, revealing microbial systems that are quite different from those at the surface. In this Nature Geoscience Insight we highlight some of the most intriguing advances in the microbial biogeochemistry of the oceans, a field that is very much in flux.
Editorial
Marine cycles in flux - p687
Anna Armstrong
doi:10.1038/ngeo1946
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Commentary
Where the genes flow - pp688-690
Frank J. Stewart
doi:10.1038/ngeo1939
Particles of organic matter in the ocean host diverse communities of microorganisms. These particles may serve as hotspots of bacterial gene exchange, creating opportunities for microbial evolution.
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Reviews
Impact of Arctic meltdown on the microbial cycling of sulphur - pp691-700
M. Levasseur
doi:10.1038/ngeo1910
The Arctic is warming faster than any other region in the world. The resultant large-scale shift in sea ice cover could increase oceanic emissions of dimethylsulphide, a climate-relevant trace gas generated by ice algae and phytoplankton.
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Processes and patterns of oceanic nutrient limitation - pp701-710
C. M. Moore, M. M. Mills, K. R. Arrigo, I. Berman-Frank, L. Bopp, P. W. Boyd, E. D. Galbraith, R. J. Geider, C. Guieu, S. L. Jaccard, T. D. Jickells, J. La Roche, T. M. Lenton, N. M. Mahowald, E. Marañón, I. Marinov, J. K. Moore, T. Nakatsuka, A. Oschlies, M. A. Saito, T. F. Thingstad, A. Tsuda & O. Ulloa
doi:10.1038/ngeo1765
Photosynthetic microbes, collectively termed phytoplankton, are responsible for the vast majority of primary production in marine waters. A synthesis of the latest research suggests that two broad nutrient limitation regimes dictate phytoplankton abundance and activity in the global ocean.
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Microbial biogeochemistry of coastal upwelling regimes in a changing ocean - pp711-717
Douglas G. Capone & David A. Hutchins
doi:10.1038/ngeo1916
Coastal upwelling regimes associated with eastern boundary currents are the most biologically productive ecosystems in the ocean. A suite of human-induced changes could perturb primary production and nutrient cycling in these highly dynamic systems.
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Microbial control of the dark end of the biological pump - pp718-724
Gerhard J. Herndl & Thomas Reinthaler
doi:10.1038/ngeo1921
The flux of carbon out of the ocean surface is not sufficient to meet the energy demands of microbes in the dark ocean. A review of the literature suggests that non-sinking particles and microbes that convert inorganic carbon into organic matter could help to meet this deep-ocean energy demand.
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Seafloor oxygen consumption fuelled by methane from cold seeps - pp725-731
Antje Boetius & Frank Wenzhöfer
doi:10.1038/ngeo1926
The leakage of cold, methane-rich fluids from subsurface reservoirs to the sea floor sustains some of the richest ecosystems on the sea bed. Microbial consumption of seep methane means that these cold-seep communities consume around two orders of magnitude more oxygen than non-seep seafloor communities.
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