The microbes in expanding dead zones

DOE Joint Genome Institute: Among the many changes in the ocean is the expansion of oxygen-deficient or oxygen minimum zones (OMZs), also known as dead zones, which affect the processes by which carbon is captured and sequestered on the seafloor and alter the microbial activities that impact the rate and magnitude of ocean carbon sequestration. Despite the importance of these effects, very little is known about the metabolism of OMZ microbes and how they respond to environmental changes.

In the Oct. 23 issue of the journal Science, researchers from the University of British Columbia and the U.S. Department of Energy Joint Genome Institute (DOE JGI) describe the metagenome of an abundant but uncultivated microbe, known as SUP05, that is silently helping to shape the ecology of OMZs worldwide. Researchers studied the microbe in Saanich Inlet, a fjord on the coast of Vancouver Island, British Columbia, Canada.

….“To our surprise the most abundant organism in the oxygen-depleted waters was this SUP05 bug,” said the paper’s senior author Steven Hallam, Assistant Professor at the University of British Columbia. …Susannah Tringe, a metagenomics scientist at the DOE JGI, said that the OMZs are sinks for an essential nutrient that marine organisms need to survive—nitrogen—as well as sources for the greenhouse gases methane and nitrous oxide. “By studying the genomes of the uncultivated microbes found in OMZs, we can better understand how they participate in global geochemical cycles such as the carbon and nitrogen cycles,” she said.

…“As habitat range expands due to global warming, blooming SUP05 populations have the potential to help offset rising carbon dioxide levels that ultimately lead to ocean acidification,” Hallam said. He added that SUP05 and its relatives will become increasingly important agents as OMZ expansion and intensification continues to unfold, providing researchers with a biological indicator useful in monitoring the changing state of the global ocean….

View from Malahat Lodge, Vancouver Island, shot by Nopukkatukka in 2005, Wikimedia Commons. Not sure how close this is to the Saanich Inlet, but at least it's not a million miles away