活動備忘 Event Memo：
Cold–seep ecosystems are widely distributed along continental margins, sustained by methane-rich fluid emissions on the seabed. Methane migrates from deep reservoirs of oil or gas, or from gas hydrate layers that act as a stock of energy for these ecosystems. High biological production at cold seeps is based on microbial chimiosynthesis, through aerobic (AeOM) or anaerobic oxidation of methane (AOM) and hydrogen sulfide oxidation coupled to AOM in the upper sediment layers. The microbial primary production is transferred to higher trophic levels either as direct food sources or via symbiosis with invertebrates. These symbiont-bearing species, the most common being siboglinid tubeworms, mytilid and vesicomyid bivalves, represent the major part of the biomass and create dense aggregations. They highly depend for their nutrition on reduced compounds and are therefore good indicators of fluid emissions. Their large size and usually epibenthic life mode make them easily visible on the seabed. They often form patchily distributed dense assemblages that can be mapped by surveys of remote and autonomous underwater vehicles. These dense patches of large-size species create habitat heterogeneity resulting in high biodiversity of associated fauna. High seep productivity also supports opportunistic background species and can be exported to the surroundings by large vagrant predators. Cold seeps are therefore biomass and biodiversity hotspots which contribute to margin heterogeneity and provide ecological key functions, goods and services. Acquiring knowledge on their distribution, temporal dynamics, and connectivity is critical to sustainable management of seabed resources. The giant Regab pockmark in the Gulf of Guinea and long term studied sites of the Gulf of Mexico will be presented as case studies of cold-seep ecosystems in areas of potential oil exploitation in the deep-sea.