Marine heatwaves disrupt ocean circulation and nutrient distribution in the Gulf of Alaska

Spring phytoplankton bloom in the Gulf of Alaska in 2017. Credit: NASA

Marine heatwaves in the Gulf of Alaska have surged since 2013, causing lasting impacts on ocean dynamics, fisheries, and marine food webs. Researchers from Brown University used 30 years of satellite data and climate models to study how marine heatwaves disrupt nutrient-rich circular ocean currents called eddies. These eddies help to concentrate nutrients that support phytoplankton, which is the foundation of the marine food chain. The study, published in Communications Earth & Environment, revealed a chain reaction. Marine heatwaves create high-pressure atmospheric conditions that weaken coastal circulation in the Gulf of Alaska, reducing the formation of the eddies essential for supporting marine life.