A research team led by the University of Rhode Island’s Graduate School of Oceanography will embark on an expedition to collect sediment samples of the deep seafloor beginning tomorrow for 38 days. The team wants to reconstruct how and why the earth’s temperature has changed over the last 20,000 years.
The research team is going to use a tube 150-feet long to retrieve sediment cores of mud at eight sites along an underwater mountain chain in the Atlantic Ocean, just north of the equator. The scientists will be aboard the R/V Knorr, owned by the Navy and operated by the Woods Hole Oceanographic Institution.
URI Professor Art Spivack, the principal investigator of the research cruise, said mud accumulates in layers with time, just as tree rings do, and reveals details about what’s happened in the ocean in the past.
The research team will reconstruct how carbon dioxide levels have varied between the last glacial period and today by studying the water in the ancient seafloor sediment. Spivack says scientists want to understand how the ocean carbon system might respond in the future by studying how it has behaved to changes in the past.
“We know there’s a very strong correlation between carbon dioxide in the atmosphere and the temperature of the earth, and we don’t really know why,” said Spivack. “And we’re going to go out and test some of the leading hypothesis.”
Spivack said they chose to work in the western north Atlantic Ocean, because it’s an area where scientists can collect cores from a range of water depths, from 1,000 to 6,000 meters, within a relatively small geographic region.
Scientists will also study the microorganisms living in sediments that are tens of millions of years old.
“It’s been recognized as part of this work and the work of others that the microbial life in the ocean sediments is a major component of the biosphere of the earth,” said Spivack. “So this is a continuation of trying to understand what kinds of organisms are in the seafloor, what controls their distribution, and how do they make a living, or how do they behave.”
These microorganisms survive with very little energy and studying their survival strategies will help us better understand life on earth and perhaps on other planets.
“What’s remarkable about those organisms is that they survive at extremely low metabolic rates, thousands of times lower than anything that had ever been observed,” said Spivack.
This expedition, funded by the National Science Foundation, requires the expertise across many different areas. Spivack said the research team is made up of geologists, microbiologists, chemists and other oceanographers from URI, Boston University, California Institute of Technology, Texas A&M University, Indiana University of Pennsylvania, Montana State University and the Japan Agency for Marine-Earth Science and Technology.
The Woods Hole Oceanographic Institution will retire the R/V Knorr after this research expedition.
“So for me it’s a little bit sentimental,” said Spivack. “This ship, the Knorr, is the first research vessel I was ever on. I was fortunate as a graduate student to be on exploration of hydrothermal vents down in the Galapagos back in the early 1980s.”
The R/V Knorr is well known for being part of the research team that discovered the Titanic.
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