The Large-Scale Role of Rivers on the Coastal Biogeochemistry in the Northern Gulf of Mexico: A Data-Driven Approach

Abstract

The northern Gulf of Mexico (nGoM) is the destination of over 50 rivers, which are highly influenced by humans and includes the Mississippi River, the largest river in the US. This project identified long-term regional trends in nutrient concentration, fluxes, ratios, and river discharges, which had important implications for future change in the coastal ocean. Key findings included peak nitrogen and phosphorus concentrations in the 1980s-2000s, long-term decreases in silica concentrations, and both regional long-term increases and decreases in discharge in different nGoM regions. Machine learning results identified salinity and riverine silica concentrations as drivers of chlorophyll-a concentrations across the nGoM while riverine silica and total phosphorus concentrations were important in driving shifts in the phytoplankton community from dinoflagellate to diatom dominance. The results of this study underscored the significance of sustained observation of the river-ocean system and demonstrated the usage of open data for conducting large-scale research.