Xie, Huixiang (Université du Québec à Rimouski)

Purpose

Methane (CH4) is the second most potent greenhouse gas in the atmosphere (after carbon dioxide). Aquatic ecosystems, including rivers, lakes, oceans, wetlands, and saltmarshes, provide an important source of atmospheric CH4. It is commonly accepted that CH4 in natural waters almost exclusively originates from methane production by certain bacteria strictly in the absence of oxygen. This long-established belief, however, contradicts the CH4 distribution in the ocean water column where CH4 concentrations are mostly supersaturated and highest in the oxic surface waters. The presence of this CH4 maximum in the surface ocean is called the “oceanic methane paradox (OMP)”.