Large, naturally occurring low-oxygen zones in the Pacific appear to be expanding, and there is a sharp change in the number of bacteria that produce and consume different forms of toxic sulfur, according to a UC Merced researcher’s latest paper in Nature Communications.
These expanding deoxygenated zones could also contribute to climate change, which, in turn, appears to contribute to their growth.
Professor Michael Beman, a marine microbial biologist with the School of Natural Sciences, spent a month on a research ship sampling water off the coast of Mexico in the large Eastern Tropical Northern Pacific, a deoxygenated zone that extends about halfway to Hawaii.
At the surface, this area of the sea is a productive fishery. But lurking underneath, from a couple of hundred meters down to about 1,000 meters, there is a deoxygenated or “dead” zone. The robust biological activity at the surface offers a lot of food for the bacteria below, and as they consume it they deplete the oxygen.
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Dead zones can be man-made, too, as in areas where a lot of freshwater runoff carries surface pollutants and biological materials into the ocean, providing a feast for bacteria that use up the oxygen other creatures need to live.
Beman’s paper, “Deoxygenation Alters Bacterial Diversity and Community Composition in the Ocean’s Largest Oxygen Minimum Zone,” shows oxygen concentrations have pronounced effects on many microbes living in the Northern Pacific zone, and there have been strong shifts in abundance, indicating the bacteria are sensitive to change.
“It’s important to figure out the long-term effects of this,” Beman said. “These zones appear to be expanding, and we’re not sure what will happen. Their expansion could produce greenhouse gases or change nutrient cycling in these areas.”
Inaugural lecture in climate series scheduled
Author Andrew Hoffman, whose work has been widely cited and mentioned in The New York Times, Scientific American, Wall Street Journal and on National Public Radio, to name a few, is the inaugural speaker for the Center for Climate Communication talk series.
His lecture, “A Great Divide: The Cultural Schism Over Climate Change,” will be at 2 p.m. April 30 in the California Room on the UC Merced campus.
In a summary about the talk, Hoffman said the social debate on climate change is no longer about carbon dioxide and climate models. It is about values, culture, world views and ideology. As physical scientists explore the mechanics and implications of anthropogenic climate change, social scientists explore the cultural reasons why people support or reject their scientific conclusions.
What has been found is that scientists do not hold the definitive final word in the public debate on this issue, he said. Instead, the public develops positions that are consistent with the values held by others within their groups. Efforts to present more data, without addressing the threat to the deeper values they have formed will only yield greater resistance and make a social consensus even more elusive.
Hoffman is the Holcim Professor of Sustainable Enterprise at the University of Michigan, a position that holds joint appointments at the Stephen M. Ross School of Business and the School of Natural Resources & Environment. Hoffman’s research uses a sociological perspective to understand the cultural and institutional aspects of environmental issues for organizations.
For more information about Hoffman visit http://andrewhoffman.net/. For more information about the event, email Professor Teenie Matlock at email@example.com.