Phytoplankton seem to enjoy naturally seeping oil on the Gulf floor, which (in small amounts) may actually contribute to the growth of these microscopic organisms, a new study finds.
For the new study – published online Monday (Jan. 25) in the journal Nature Geoscience – Ajit Subramaniam, an oceanographer at Columbia University’s Lamont-Doherty Earth, looked at the effects that natural oil seeps have on phytoplankton in the Gulf of Mexico.
Professor Subramaniam found that in areas where oil was seeping naturally, the microorganisms were twice as concentrated, compared with phytoplankton in cleaner waters. At lower concentrations, oil may help some microbes in the Gulf survive, he said. However, exposure to oil at other concentrations could be bad for the phytoplankton.
The new study was based on data collected by researchers from Florida State University. Researchers were trying to figure out how much of the oil from the Gulf came from the Deep Horizon spill in 2010 and the amount that seeps naturally. The results showed that about 160,000 to 600,000 barrels come from naturally occurring seeps each year, compared with a little over four million barrels that were release from the oil spill.
Ian MacDonald, an oceanography professor at Florida State University, said that the impact from the Deepwater Horizon spill was a lot more concentrated in time and space, than natural oil seeps – which only become significant over time. Based on the study results, the researchers were able to find the exact geographic points where oil from the Deepwater Horizon spill was located.
To study the effects of natural oil seeps on microorganisms, the researchers used synthetic aperture radar (SAR). Several hundred feet under the water surface, researchers found the highest concentration of phytoplankton. Here, the microscopic organisms could get all the rising nutrients and the sunlight they needed.
Michael Behrenfeld, a marine ecology professor at Oregon State University in Corvallis, said that the new research may inspire similar studies in other locations around the world. For instance, it is known that hydrocarbon seeps are quite common along many continental margins. An interesting research would be to see how hydrocarbon seeps in the deep ocean are altering the dynamics of surface phytoplankton, Behrenfeld noted.
Image Source: news. fsu. edu