Temperature controls carbon cycling and biological evolution in the ocean twilight zone

Getting more pumped It is thought that the ocean's biological carbon pump, the process that transfers organic matter from the surface to the deep ocean, should be sensitive to climate change because temperature controls photosynthesis and respiration rates. Boscolo-Galazzo et al. show that the efficiency of the biological carbon pump increased over the past 15 million years as the oceans cooled because of a reduction in the rate of the breakdown of sinking organic matter (see the Perspective by Bopp). The resulting redistribution of nutrients at depth could have affected plankton evolution and expanded the mesopelagic “twilight zone” ecosystem. Science , this issue p. 1148 ; see also p. 1099