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. The fjord undergoes a seasonal cycle of stratification and deep water renewal, creating strong water column gradients that make it an ideal "living lab" to study microbial communities adapted and specialized to thrive under low oxygen conditions such as those found in OMZs. To chart the SUP05 metagenome, genetic material was recovered directly from environmental samples encompassing the entire microbial community of Saanich Inlet during different stages of water column stratification and deep-water renewal.
"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. "We obtained enough DNA sequence coverage from the community of microbes to actually assemble a continuous stretch representing what we are calling the SUP05 metagenomeit's a composite of the entire SUP05 population spanning the various environmental samples that we sequenced."
Susannah Tringe, a metagenomics scientist at the DOE JGI, said that the OM
|Contact: David Gilbert|
DOE/Joint Genome Institute