Marine Heatwaves Disrupt Ocean Food Webs and Slow Deep Sea Carbon Sequestration

New research reveals that marine heatwaves significantly disrupt ocean food webs and the biological carbon pump, reducing the ocean's ability to sequester carbon and mitigate climate change. Studying over a decade of data from the Gulf of Alaska, including two major heatwaves termed "The Blob" (2013–2015) and another from 2019–2020, scientists observed that these events altered phytoplankton communities, causing carbon to accumulate at shallower depths instead of sinking efficiently to the deep ocean. This disruption hampers the ocean's role as a "conveyor belt" that transports carbon from surface waters to the deep sea, increasing the risk that carbon will return to the atmosphere. The research was a collaborative effort involving institutions such as the Monterey Bay Aquarium Research Institute, University of Miami, and Fisheries and Oceans Canada, utilizing advanced robotic floats from the Global Ocean Biogeochemical Array project. These findings underscore the broader implications of marine heatwaves on oceanic biogeochemical cycles and their potential to weaken the ocean's climate buffering capacity. The study emphasizes the critical need to understand and address the impacts of warming oceans on microscopic marine life and global carbon dynamics.