Mesoscale Processes' Effects on Spatial and Temporal Variability in the Ocean's Biological Carbon Pump

Abstract

The ocean is a significant carbon sink through both physical and biological processes. The biological carbon pump (BCP) injects organic carbon into the interior ocean via sinking organic matter, mixing, and subduction. Small scale processes in the ocean like eddies (scales < 100km) affect the BCP by altering the sinking, mixing, and subduction. Eddies introduce strong spatial variability in the export flux, making it difficult to estimate the global export of carbon by the BCP from in-situ sampling. The NASA EXPORTS project aims to better understand the BCP and its variability due to eddies. As part of this project we use an eddy-resolving ocean model to examine how the undersampling of spatial variability will impact the estimates of export and design a sampling strategy for the upcoming cruise part of the EXPORTS project. We confirm previous studies’ results that high-resolution sampling is necessary to capture the spatial variability in export. The EXPORTS cruise will benefit from having a second ship that is able to take high spatial-resolution export measurements throughout the sampling region. Although difficult to measure, subduction and mixing prove to have a significant impact on export and the associated sampling bias.