How phytoplankton survive in ocean gyres with low nutrient supplies
Subtropical gyres are huge, sustained currents spanning thousands of kilometers across the Pacific and Atlantic oceans, where very little grows. With nutrients in short supply, phytoplankton, the microscopic plants that form the basis of the marine food chain, struggle to thrive. However, some phytoplankton do live within the hostile environment of these gyres, and exactly how they obtain their nutrients has long been a mystery. Now research by Edward Doddridge, a postdoc in the Department of Earth, Atmospheric and Planetary Sciences at MIT, has found that phytoplankton growth in subtropical gyres is affected by a layer of water well below the ocean surface, which allows nutrients to be recycled back to the surface. Working with David Marshall at Oxford University, Doddridge has developed a model to investigate the mechanism behind phytoplankton growth within the gyres, which appears in the Journal of Geophysical Research: Oceans. According to the textbooks, winds push surface waters into the center...