Research charts the ecological impact of microbial respiration in the oxygen-starved ocean

Jul 23, 2014

A sulfur-oxidizing bacterial group called SUP05 will play an increasingly important role in carbon and nutrient cycling in the world's oceans as oxygen minimum zones expand, according to research published this week in the Proceedings of the National Academy of Sciences.

University of British Columbia researchers plumbed the depth of a seasonally anoxic fjord, Canada's Saanich Inlet, to chart how microbial community metabolism changes as oxygen minimum zones form.

"Our study paints a very detailed picture of how SUP05—a bacterial group related to gill symbionts of deep-sea clams and mussels—dominates the microbial ecology of oxygen-starved regions of the water column," says UBC microbiologist and study author Steven Hallam.

"SUP05 breathes in nitrate and exhales nitrous oxide. This respiratory process drives and the removal of toxic hydrogen sulphide and closely couples the metabolic activities of SUP05 with other microorganisms involved in carbon, nitrogen and sulfur cycling."

Saanich Inlet, a fjord on Vancouver Island in British Columbia, undergoes seasonal cycles of stratification and deep-water renewal, creating strong water column gradients that make the Inlet a natural lab in which to study microbial communities that thrive under oxygen starved conditions. Hallam's team dissected the layer by layer using genomic and proteomic methods.

Dissolved oxygen concentration is a critical organizing principle in ocean environments. Over the past 50 years oxygen minimum zones have expanded due to climate change and increased waste run-off from farms and cities. At present eight per cent of the ocean is considered oxygen-starved. In some coastal areas extreme oxygen-starvation produces 'dead zones' that decimate marine fisheries and destroy food web structure.

Changes in microbial community metabolism associated with oxygen minimum zones alter the ocean's nutrient and energy flow patterns, also impacting the production and consumption of greenhouse gases.

Explore further: Viruses hijack deep-sea bacteria at hydrothermal vents

More information: PNAS 2014 ; published ahead of print July 22, 2014. www.pnas.org/content/early/201… 7/22/1322132111.long

add to favorites email to friend print save as pdf

Related Stories

Nitrous oxide from ocean microbes

Dec 10, 2007

A large amount of the greenhouse gas nitrous oxide is produced by bacteria in the oxygen poor parts of the ocean using nitrites, Dr Mark Trimmer told journalists at a Science Media Centre press briefing today.

Recommended for you

Icelandic volcano sits on massive magma hot spot

7 hours ago

Spectacular eruptions at Bárðarbunga volcano in central Iceland have been spewing lava continuously since Aug. 31. Massive amounts of erupting lava are connected to the destruction of supercontinents and ...

NASA sees Tropical Storm Ana still vigorous

9 hours ago

NASA's TRMM satellite saw that Tropical Storm Ana was still generating moderate rainfall is it pulled away from Hawaii. The next day, NASA's Aqua satellite saw that wind shear was having an effect on the ...

User comments : 0