CORVALLIS, Ore. - Oregon State University researchers have received a major grant from the Gordon and Betty Moore Foundation to compare microbial abundance, diversity and activity in hypoxic waters off the coasts of Oregon and central Chile.
Both locations experience seasonal low oxygen conditions known as hypoxia that can lead to biological "dead zones."
The three-year, $5 million grant is important because it will help acquire baseline data on the microbial assemblages in coastal waters and how they respond to environmental perturbations. This information will also serve to better define the potential evolution of these ecosystems under a climate change scenario, the researchers say.
"Most people look at life in the ocean and think of whales, or salmon," said Ricardo Letelier, a professor in OSU's College of Oceanic and Atmospheric Sciences and principal investigator on the grant. "But microbes are the most abundant marine life form and yet we have identified less than 1 percent of their diversity in the ocean.
"The more we know about species diversity and processes, the better we'll be able to gauge how the marine environment responds to different stresses," he added. "On the other hand, the earliest life on Earth was developed during anoxic (no oxygen) conditions, so these studies may also give clues to some of the past life on our planet."
The foundation also has awarded Oregon State a second grant, this one for $3.1 million to continue the research of Stephen Giovannoni, an OSU microbiologist whose studies of a group of marine bacteria known as SAR11H have garnered national attention. In papers published in prestigious journals Science and Nature, Giovannoni describes how SAR11 has become the ocean's most ubiquitous life form - largely by having the simplest genome of any cell that lives free in nature.
Giovannoni is part of a group working with Letelier on the new study, which will compare "Oxygen Minimum Zones," or OMZs, off the coasts of central Oregon and north-central Chile. The Chilean hypoxic zone is considered stable because, although it reoxygenates during winter, it forms roughly at the same time (late winter) every year and extends to the continental shelf during summertime. Oregon, on the other hand, has experienced hypoxia in near-shore waters only recently and the processes are much less predictable.
Among issues the scientists will address is how much microbial diversity there is in these two regions, how they compare, and what the different mechanisms are that contribute to important chemical cycles, including the storage of organic carbon in the seafloor or its release into the atmosphere as carbon dioxide. They plan to conduct a series of experiments to study the gene transcription of different microbes and determine whether they are affected by low oxygen conditions.
The project also includes a paleo-oceanography component that will seek to understand the long-term evolution of these low-oxygen regions off Oregon and central Chile.
How many different kinds of microbes are there?
"Thousands, millions, we don't know," Letelier said. "With microbes, it's hard to know because to the naked eye most bacteria and archaea look the same. Also the genetic boundaries can be somewhat tenuous. For example, when a virus takes a piece of bacterium and transfers it to another bacterium, it becomes a new entity. Before we answer that question, we need to define just what a species is when referring to microbes."
OSU scientists will collaborate with colleagues at Universidad de Concepcion in Chile led by Osvaldo Ulloa to compare the physical, biochemical, microbial and paleo-oceanographic characteristics of both coastal systems. In addition, they will send microbial samples for genetic analysis to Stephan Schuster at Penn State University and Edward DeLong at the Massachusetts Institute of Technology. The OSU team includes oceanographers Jack Barth and Alan Mix, zoologist Francis Chan and microbiologist Giovannoni.
Barth, who has been a leader in the study of low-oxygen zones off the Oregon coast, said the researchers hope to see if they can identify an isotopic signature of different microbes' response to low oxygen and compare that with other evidence, including sediment cores and the rings on soft corals. They hope this process could allow the scientists to extend the scientific record of hypoxia back in time.
"This is still an evolving field," Letelier said. "We didn't know so many different organisms existed and it wasn't until the 1980s that we identified Prochlorococcus, which is responsible for about 50 percent of the photosynthesis in the world. And it was only 20 years ago that we discovered archaea, a group of single-celled organisms that may comprise the most abundant groups of species in the world."
The Gordon and Betty Moore Foundation, established in 2000, seeks to advance environmental conservation and cutting-edge scientific research around the world and improve the quality of life in the San Francisco Bay area. The foundation's Marine Microbiology Initiative supports discovery and dissemination of scientific findings and technological developments in the fields of marine microbiology and microbial ecology, which contribute to ocean health and productivity. For more information, visit: http://www.moore.org/.
Letelier is an investigator for a National Science Foundation-funded Science and Technology Center, which is a collaborative effort among the host University of Hawaii, OSU, Monterey Bay Aquarium Research Institute, University of California-Santa Cruz and MIT. The $19 million Center for Microbial Oceanography: Research and Education, or C-MORE, is designed to study the ocean's most abundant biomass and its role in the biological food chain and sequestering atmospheric carbon dioxide.
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