Understanding the consequences of changing phytoplankton elemental use efficiencies for global ocean biogeochemistry

A major focus of biological oceanography is to understand and quantify the effects of temperature and resource availability on phytoplankton productivity and ecosystem dynamics in the world ocean.

Classic paradigms like Eppley's temperature curve and the resource response relationships of Liebig and Monod have served the field well, but they fail to capture the full dynamic and interactive nature of resource availability and temperature influences on primary production.

This shortcoming is especially problematic for earth system modelers as they urgently try to estimate future oceanic productivity levels that underpin projected changes in the ocean ecosystem, properties that are needed to inform policy makers such as the assessment reports of the IPCC and IPBES.

This proposal describes a closely coordinated collaborative project between two U.S. marine microbiologists and a biogeochemical modeler from the U.K. that will apply the emergent concept of Elemental Use Efficiencies (EUEs) to integrate flexible thermal and resource limitation responses into a new generation of earth system models.

EUEs are defined as the amount of carbon fixed, per unit of cellular nutrient resource, per unit time.

This simple, yet novel concept provides a unique opportunity to integrate the observed consequences of concurrent warming and altered nutrient availability for primary productivity in ocean models to quantify biogeochemical and biological responses in the rapidly changing ocean environment.