"A neural network-driven Earth system model has led University of California, Irvine oceanographers to a surprising conclusion: Phytoplankton populations in low-latitude waters will expand by the end of the 21st century.

The unexpected simulation outcome runs counter to the longstanding belief by many in the environmental science community that global climate change will make tropical oceans inhospitable to phytoplankton, which form the base of the aquatic food web. The UCI researchers provide the evidence for their findings in a paper published today in Nature Geoscience.

Senior author Adam Martiny, UCI professor of Earth system science and ecology & evolutionary biology, explained that the prevalent thinking on phytoplankton biomass stems from the expectation of an increasingly stratified ocean. Warming seas inhibit mixing of the heavier cold layer in the deep with lighter warm water closer to the surface. With less circulation between the levels, fewer nutrients reach the higher strata to be accessed by hungry plankton.

“All the climate models have this mechanism built into them, and it has led to these well-established predictions that phytoplankton productivity, biomass and export into the deep ocean will all decline with climate change,” Martiny said. “Earth system models are largely based upon laboratory studies of phytoplankton, but, of course, laboratory studies of plankton are not the real ocean.” "

https://news.uci.edu/2020/01/27/contradicting-prevalent-view-uci-oceanographers-...