Marine scientists have uncovered a previously unknown source of methane emissions in nutrient-depleted ocean regions, according to a study published in Nature Geoscience. The discovery suggests climate models may be underestimating future methane release as warming waters reduce nutrient mixing.
The international research team found that specialized archaea microbes produce methane when starved of phosphorus and nitrogen. This occurs even in oxygen-rich surface waters previously thought incapable of methane generation. “We’ve solved a 30-year mystery about why we detect methane where conventional wisdom says it shouldn’t exist,” said lead researcher Dr. Helena Markovic.
Climate scientists warn this could create a feedback loop: warmer waters reduce nutrient circulation → more microbes switch to methane production → increased atmospheric methane → amplified warming. Current models don’t account for this mechanism.
The study analyzed water samples from the Pacific Ocean’s “shadow zones” – vast mid-depth regions with minimal currents. Methane concentrations here were 3-5 times higher than expected. Researchers estimate these microbial sources could add 10-15% to current ocean methane emission projections by 2100.
“This isn’t an immediate crisis, but it’s another piece in the climate feedback puzzle we need to understand,” noted Woods Hole Oceanographic Institution’s Dr. Raj Patel, who wasn’t involved in the study. The findings come as NOAA reports 2025 saw record ocean temperatures for the 12th consecutive year.