NASA-backed sea-level research focuses on Island
A team of scientists believes that Bermuda’s mangroves and coral reefs hide information about the history of the Atlantic’s ever-changing sea levels.A NASA-funded team of researchers, including Bermudian Lisa Rodrigues, an assistant professor at Villanova University, has been collecting samples from the Island for the past two weeks.Their aim is to complete a study into how sea levels have changed over the last 2,000 years.Andrew Kemp, of Yale University, said: “The plan is to try to do it in two ways, by both looking at sediment in the mangroves and by looking at the growth and erosion of coral.“The idea is that mangroves accumulate sediment to keep themselves at a particular sea level. If the ocean goes up, they need to keep in pace with it.”Similarly, he said the Island’s reefs can provide a map of the ocean’s history as the coral species that formed the reefs are affected by the changing environment.“There are only a few places in the world coral and mangroves in such close proximity can both be used to reliably reconstruct sea levels,” Dr Kemp said. “Bermuda is also unusual in that it is in the middle of the Atlantic Ocean, while most of the data we have comes from continental coasts.”Ryan Moyer, from the US Geological Survey, said: “The coral has been around for at least 10,000 years, at least the shallow reef.“We can do dating further back, but in this case we are trying to compare it to the mangroves’ results, so anything we get beyond 2,000 years is a bonus.”He said that while a great deal of research has been done on reefs in the Pacific, there has been relatively little work on recent sea level changes from Atlantic reefs.The differences between the oceans cause unique challenges in both areas, Dr Moyer added.Not only do the oceans feature entirely different species of corals, but while the relative sea level in the Atlantic is rising, it is lowering in the Pacific.“The water in the Pacific is receding, so they can find them on land,” he said. “They can start on the top, but [in the Atlantic] we have to start on the bottom and work our way up.”Geological factors, such as the moving of the tectonic plates, can cause land masses to rise or sink comparative to sea levels over the course of millions of years.Simon Engelhart, from the University of Pennsylvania, explained: “The ocean isn’t like a bath tub which just fills up as you put water in it. It’s a lot more complex than that.”The team, which also included Daria Nikitina from West Chester University and Benjamin Horton, are scheduled to return to the US on Monday.Dr Kemp said he hopes to start getting results from the study in the next six to twelve months.“The radio carbon dating itself will take about three months,” he said.Once the research is complete, the plan is to compare and contrast the findings, not only between the mangroves and the reefs, but between records from other areas of the world to form a more complete picture of the ocean’s history.“The main idea is to compare the sea level with the climate, but we could also take this data to look at things like ice distribution, which aren’t that interesting to the public but really interesting to geologists,” Dr Kemp said.