A Coupled Epipelagic Meso-/Bathypelagic Particle Flux Model for the Bermuda Atlantic Time-Series Station/Oceanic Flux Program Site

Woods Hole Oceanographic Institution, Woods Hole MA

Investigators

Abstract

ABSTRACT OCE-0097288 In this project researchers at the Woods Hole Oceanographic Institution will construct a mathematical model relating the fixing of atmospheric carbon dioxide by primary production in the North Atlantic Ocean to the export of that carbon to the deeper ocean. They will combine observations of deep-water sediment traps (in operation for 21+ years) at the Oceanic Flux Program (OFP), euphotic zone measurements (10+ years) at the Bermuda Atlantic Time-series Site (BATS), and historical meso/bathypelagic zooplankton data with an ecosystem-based biogeochemical model of particle flux from the epipelagic to meso/bathypelagic zone. There is a remarkably strong covariance between the upper ocean particle flux at BATS and the deep particle flux measured by the OFP traps, as well as intense modification and strong convergence of the composition of the particle flux with depth to a invariant composition with respect to the magnitude of mass flux. Of fundamental concern is how changes in ocean remineralization will affect the magnitude of material fluxes through the water column, which is one of the major research trajectories of the Synthesis and Modeling Project of the U.S. Joint Global Ocean Flux Study. The central objective of the project is to mechanistically connect euphotic zone processes with meso- and bathypelagic zone processes by means of a prognostic model that can be used to further our understanding of these unparalleled time-series data and to test hypotheses constrained by a battery of in situ data. To do this, the PIs will derive a meso/bathypelagic ecosystem structure and use it to model the flux of biogeochemically active constituents (carbon, nitrogen and silica). The meso/bathypelagic portion of the model would be driven by a well-established epipelagic model coupling a moderately complex, yet robust, ecosystem model with a state-of-the-art physical upper-ocean mixing model. The choice of driver derives from the underlying hypothesis that the meso/bathypelagic activity inferred from the sediment trap data is a response to time-varying responses of the upper ocean ecosystem to events of meteorological scale.