The ISME Journal (2026). DOI: 10.1093/ismejo/wrag057"> Study area, geochemistry and microbial community composition. Credit: The ISME Journal (2026). DOI: 10.1093/ismejo/wrag057 The world's oceans are losing oxygen—and rapidly. The principal cause is the increasing warming of the oceans, which reduces the solubility of oxygen in water and increases respiratory activity. In addition, it strengthens stratification of the water column, making it harder for deep and surface water to mix. "Within just 50 years—from 1960 to 2010—the global oxygen content of the oceans fell by 2% and the volume of anoxic waters increased fourfold," says biogeochemist Dr. Gonzalo Gomez Saez from the Department of Earth and Environmental Sciences at LMU.…