Tiny ocean organisms living in oxygen-poor waters turn nutrients into nitrous oxide—a greenhouse gas far more powerful than carbon dioxide—via complex chemical pathways.

Penn’s Xin Sun and collaborators identified the how and why behind these chemical reactions, showing that microbial competition, not just chemistry, determines how much N₂O is produced.

Their findings pave the way for more reliable climate models, making global greenhouse gas estimates more effective, predictable, and easier to understand in response to natural and man-made climate change.

A new study from researchers at MBARI and the University of Miami Rosenstiel School of Marine, Atmospheric, and Earth Science—with an interdisciplinary team of collaborators from the Hakai Institute, Xiamen University, the University of British Columbia, the University of Southern Denmark, and Fisheries and Oceans Canada—has revealed the impacts of marine heatwaves on the foundation of the ocean food web. Pairing data from robotic floats deployed as part of the Global Ocean Biogeochemical Array with eDNA samples from ship-based plankton surveys, the team found that marine heatwaves can reshape ocean food webs, which in turn can slow the transport of carbon to the deep sea and hamper the ocean’s ability to buffer against climate change.