Iron-deficient phytoplankton don’t absorb as much CO2, study finds

Phytoplankton’s ability to absorb carbon dioxide is hindered by a lack of iron in their diet, according to a study in Nature. Climate models have estimated that phytoplankton in the world’s oceans have absorbed about 55 billion tons of carbon dioxide, but the new research suggests that anemic Pacific Ocean phytoplankton have sequestered up to 2.2 billion tons less than previously estimated. While the discovery will not completely throw off climate predictions, “In the tropical Pacific that change is a significant amount,” says lead author Michael Behrenfeld. Dust blown in from deserts is a major source of iron in the oceans; as climate change creates new wind patterns, the ocean’s iron content — and coinciding phytoplankton carbon uptake — may change as well.