Impacts of Plankton and Remineralization Temperature Sensitivities on Primary Production and Carbon Fluxes

Abstract

Temperature modulates ocean biogeochemistry by influencing planktonic physiological rates and heterotrophic remineralization. While some temperature dependencies of processes such as phytoplankton photosynthesis, zooplankton metabolism and organic matter remineralization are included in biogeochemical models, regional and group‐specific variability in plankton temperature sensitivities, as well as spatial variations in remineralization responses, are often overlooked. In this study, we derived temperature coefficients for different plankton types and spatially varying remineralization temperature sensitivities from published data, and incorporated these parameters into the Community Earth System Model. We then conducted simulations under both present‐day and future climate scenarios to evaluate their impacts on marine ecosystem dynamics and carbon cycling. Our results suggest that regional and group‐specific temperature sensitivities of plankton, in combination with the temperature‐dependent remineralization, strongly influence the spatial distribution of particulate organic carbon (POC) flux. Under present‐day climate conditions, high‐latitude regions show synchronous reductions in primary production and POC flux when biologically refined temperature coefficients are applied. In contrast, low‐latitude oceans exhibit asynchronous patterns—characterized by increased primary productivity but reduced POC export—driven by both varying temperature dependence of plankton growth and remineralization. Under future warming scenarios, these updated temperature dependencies result in a greater increase in global primary productivity, yet are consistently accompanied by declined POC export and increased deep‐ocean POC flux. Overall, these findings underscore the importance of incorporating region‐ and group‐specific temperature dependencies for accurately capturing the variability of biological and chemical processes under climate change.