Ocean acidification may cause dramatic changes to phytoplankton

By Rehana Dada

Ocean acidification will spur significant changes in phytoplankton species around the world, with some populations flourishing, some shifting their ranges polewards, and others dying out. This is according to a team of researchers from the Massachusetts Institute of Technology, University of Alabama and other institutions. Ocean acidity has increased since pre-industrial times as a result of increased uptake of carbon dioxide, with oceans absorbing about 30 percent of human released carbon dioxide. Ocean acidity is projected to drop to a pH of about 7.8 by 2100, which is significantly lower than levels seen in any open ocean marine communities today. Pre-industrial ocean acidity was well over a pH of 8. Although there are other climate drivers in oceans, acidification was shown to have a greater impact on phytoplankton than warming, altered light conditions, or nutrient reduction. Phytoplankton are the base of the marine food chain, and there are likely to be impacts all the way up the chain. The research was published in Nature Climate Change on 20 July 2015.