Decline of autotrophic picoplankton in a warming subtropical ocean

Abstract

Aquatic Sciences Meeting (Aquatic Sciences: Global And Regional Perspectives - North Meets South), 22-27 February 2015, Granada, Spain.The oligotrophic subtropical gyres represent with 70 percent of the ocean surface, the largest biome on Earth, where picoplankton represent the dominant autotrophs. Predicting the response of autotrophic picoplankton to warming in the subtropical ocean is, therefore, of major consequence for biogeochemical and ecological processes in the ocean. The trend for autotrophic picoplankton to increase with temperature in the ocean has lead to predictions that autotrophic picoplankton will increase with warming, in contrast with the documented trend towards a decline in autotroph biomass and production with warming and the associated stratification in the subtropical ocean. Here we show that warming and oligotrophication, with the associated increase in photosynthetic active radiation and UV-B radiation at depth, are expected to result in a decline by 18 to 42 percent in the abundance of autotrophic picoplankton, but an increase as the dominant component of the autotrophic community in the subtropical ocean. Our study is based in the large data set compiled during the Malaspina 2010 expedition, across the Atlantic, Indian and Pacific OceansPeer Reviewe