Program

Biogenic climate-active gases (BCAGs) are the gases that are produced by biological processes and have certain influences on the change of the climate. Most of the BCAGs, such as methane (CH₄) and nitrous oxide (N₂O), exacerbate the global warming impact, while dimethyl sulfide (DMS) is a biogenic gas that actually can lower the global warming impact. Marine microorganisms actively participate in the production, consumption and transformation of the various BCAGs. For example, CH₄ is a very potent greenhouse gas and it is produced by diverse archaeal methanogens in oxygen-depleted environments. On the other hand, CH₄ is consumed by aerobic methane-oxidizing bacteria under oxic conditions and by anaerobic methane-oxidizing archaea (ANME) under anoxic conditions. N₂O is another potent greenhouse gas that is also produced, consumed and transformed by microorganisms. N₂O is mainly produced by denitrifying microorganisms as an intermediate metabolic product and by nitrifying microorganisms as a metabolic byproduct. Some other microbial metabolic reactions, such as anaerobic ammonia oxidation (anammox), may also generate N₂O. The consumption of N₂O also depends on microbial metabolic reactions, majorly the denitrification process. Many marine phytoplankton synthesize dimethylsulfoniopropionate (DMSP) as an important osmolyte and many bacteria harbor the enzymes that can transform DMSP to DMS. The metabolization of BCAGs is not only important to the global climate but also important to the marine biogeochemical cycles of carbon, nitrogen and sulfur. This talk is going to present an overview of the key microbial functions that are involved in the BCAG metabolic processes in marine environments.