Photosynthesis in the Open Ocean

摘要

Global primary productivity (the fixation of carbon dioxide, CO_2, into organic matter) fuels food production on land and in the sea. About half of this CO_2 fixation occurs in the sea, mainly by a type of phytoplankton called cyanobac-teria (1). Recent reports (2-4) have shown that a key characteristic of oxygenic photosynthesis-the electron flux through photosynthetic reaction centers coupled to oxygen (O_2) evolution-is variable, thus uncoupling oxygen cycling from CO_2 fixation. This insight has implications for how phytoplankton have adapted to the marinernenvironment and for how we measure the productivity of the oceans.