Modeling the Impacts of Phytoplankton Plasticity in Buffering Anthropogenic CO2 Increase

It is increasingly appreciated that the stoichiometry of elements in the phytoplankton can vary depending on the environmental conditions (nutrient, light, and temperature etc.) and on the taxa. Mechanistically driven, variable stoichiometry is not yet incorporated into numerical models of global ocean carbon cycle. Here we explore future carbon cycle using an optimum resource allocation model of phytoplankton coupled to an intermediate complexity Earth system model. We report on the possibility that future anthropogenic CO₂ increase can partly buffered by an increase in export production by phytoplanktons with higher C: P ratios that flourish in subtropical gyre regions under a warming planet. The preliminary study highlights the importance of allowing phytoplankton stoichiometry to vary as a function of changing environment from the traditionally fixed C: N: P ration of 106: 16: 1 (known as the Redfield Ratio).