Temperature‐Regulated Turnover of Chromophoric Dissolved Organic Matter in Global Dark Marginal Basins

Oceanic absorption of heat generated by greenhouse gas emissions has resulted in warming the dark ocean (>200 m) that contains a large refractory DOM (RDOM) pool. However, changes microbially mediated production and degradation dynamics for RDOM components response to marginal basins remain unclear. Herein, we integrated data from South China, Mediterranean Japan Seas (temperature range: 0.09–15.1°C) demonstrate situ efficiency two ubiquitous humic-like fluorophores increased at higher temperature, whereas chromophores wavelength 325 nm (aCDOM(325)) changed temperature. Increased oxygen consumption reduction labile substrates future warmer environments may initiate final some semi-refractory components, thereby increasing recalcitrance RDOM, but decreasing inventory creating positive feedback rising atmospheric CO2.