A new study highlights the detrimental effects of marine heat waves on the ocean's carbon sequestration process, particularly in the northeastern Pacific. During two significant heat waves from 2013 to 2020, changes in phytoplankton and zooplankton populations were observed, which impeded the downward transport of carbon. Warmer surface waters, combined with reduced nutrient availability, favored smaller phytoplankton species, resulting in less effective carbon sinking. This shift in the ecosystem dynamics could lead to increased atmospheric CO2 levels, as carbon-rich waters are less likely to sink and more likely to return to the surface. Researchers emphasize the need for ongoing monitoring of marine heat waves to understand their broader implications for ocean health and climate stability.