URI oceanographer to lead return visit to least inhabited place on Earth
(麻豆淫院Org.com) -- Four University of Rhode Island oceanographers depart next week for an international research expedition to the middle of the South Pacific Gyre - an area that is as far from any continent as is possible to go on Earth鈥檚 surface - to look for evidence of life far beneath the seafloor.
The expedition is a follow-up to a 2006/2007 visit to the same sites where the scientists found so few organisms living in the shallow sediment that this region may be the least inhabited marine sediment ever explored. This year鈥檚 nine-week expedition seeks to look for evidence of life in the older, deeper sediment and 鈥渢he basaltic basement.鈥�
鈥淲e鈥檒l be drilling holes in the South Pacific seafloor through the entire sediment column and into the basaltic basement to look for evidence of life and habitability in one of the most energetically challenging environments on Earth,鈥� said Steven D鈥橦ondt, a URI oceanography professor who will lead the expedition.
鈥淲e found very little evidence of life in the near-surface sediment, so now we鈥檙e going to drill deep to see what communities are like in even older sediment and rock that鈥檚 even lower in food,鈥� he added.
The team will depart from Tahiti on Oct. 9 aboard the 469-foot JOIDES Resolution, a drilling ship owned by the Integrated Ocean Drilling Program. The sediment cores they recover will then be analyzed for their chemistry and microbial communities to detect evidence of life.
鈥淪ince we found very little evidence of life in the surface sediments, there will probably be even less below,鈥� D鈥橦ondt said.
The research team includes 100 scientists, technicians and crew from a dozen countries around the world. In addition to D鈥橦ondt, other scientists participating from the URI Graduate School of Oceanography include David Smith, Arthur Spivack and Dennis Graham.
Gyres are semi-still areas in the middle of the oceans where there is little wind, little current, and very little upwelling of deep water, so the water is clear and contains few nutrients. The South Pacific Gyre is the largest of Earth鈥檚 gyres, encompassing an area twice the size of North America. D鈥橦ondt describes its center as 鈥渢he deadest spot in the ocean.鈥�
Because the region is so far from terrestrial sources of sediment and so few organisms live in its water, its sediment accumulates extraordinarily slowly - as few as 8 centimeters per million years. D鈥橦ondt said that the burial rate of organic matter was so low in the sediment that the principal food source for the microorganisms living there may be hydrogen released by the radioactive splitting of water due to the natural decay of elements in the sediment.
A main objective of the expedition is to test whether microbial communities can be sustained by this process.
鈥淲e don鈥檛 know anything about life there in this deepest, oldest sediment,鈥� said D鈥橦ondt. 鈥淚t could tell us about the possibility of life elsewhere. If organisms can survive there, then perhaps they can be supported by the same processes on Mars or Jupiter.鈥�
It is also possible that some of the microbes they find may have applications that could ultimately benefit humans.
Provided by University of Rhode Island
