Region: Western Atlantic

The Malvinas Current offshore of Argentina — a branch of the Antarctic Circumpolar Current — carries nutrients and cold water from the south, boosting primary productivity in the Southwest Atlantic Ocean. Underwater canyons along Argentina’s continental slope create irregularities in the seafloor that could change the path of this powerful current, facilitating an exchange of water masses between the shelf and the open Ocean. Scientists hypothesize that, as a consequence of this dynamic, massive phytoplankton blooms and biodiversity hotspots are present near the canyon heads in these waters. 

The Rio de la Plata drains into the Atlantic Ocean, delivering sediment-rich contents from the Paraná and Uruguay Rivers, each fed by myriad streams and tributaries. The mixing of fresh water with the nutrient-rich seawater upwelled along the continental shelf fosters remarkable biodiversity. Vulnerable Marine Ecosystems, or VMEs, are critical yet fragile habitats that support a diverse array of species, and human activities pose a significant threat to these ecosystems. Currently, there is only one reported VME in Uruguay. It is home to cold-water coral reefs formed by Desmophyllum pertusum, a slow-growing coral that grows throughout the Atlantic Ocean; experts suspect this ecologically important animal is threatened and in decline. Scientists believe there are more vulnerable ecosystems, but have not had access to the technology needed to describe deep-water areas in Uruguayan waters.

Two powerful currents converge in the Mar del Plata Submarine Canyon in Argentina’s Exclusive Economic Zone. One is warm and salty; the other is nutrient-rich and cold. Together, they form the Brazil-Malvinas Confluence, one of the most energetic regions in our global Ocean. These currents help to redistribute heat from the tropics to the poles and play a prominent role in the Earth’s climate. While scientists know these currents support submarine canyon ecosystems, their effects have never been visualized. This expedition will explore the diversity and distribution of seafloor communities in one of the country’s largest deep-sea canyons.