TY - JOUR T1 - Respiration of bivalves from three different deep-sea areas: cold seeps, hydrothermal vents and organic carbon-rich sediments A1 - Khripounoff,Alexis A1 - Caprais,Jean-Claude A1 - Decker,Carole A1 - Le Bruchec,J. A1 - Noel,Philippe A1 - Husson,Berengere AD - IFREMER, Ctr Brest, Dept REM EEP LEP, CS 10070, F-29280 Plouzane, France. UR - https://doi.org/10.1016/j.dsr2.2016.05.023 DO - 10.1016/j.dsr2.2016.05.023 KW - Deep-sea KW - Benthic chamber KW - Vesicomyid and Mytilid bivalves KW - Respiration rate KW - Cold seep KW - Hydrothermal vent N2 - We studied bivalves (vesicomyids and mytilids) inhabiting four different areas of high sulfide and methane production: 1) in the Gulf of Guinea, two pockmarks (650 m and 3150 m depth) and one site rich in organic sediments in the deepest zone (4950 m average depth), 2) at the Azores Triple Junction on the Mid-Atlantic Ridge, one hydrothermal site (Lucky Strike vent field, 1700 m depth). Two types of Calmar benthic chambers were deployed, either directly set into the sediment (standard Calmar chamber) or fitted with a tank to isolate organisms from the sediment (modified Calmar chamber), to assess gas and solute exchanges in relation to bivalve bed metabolism. Fluxes of oxygen, total carbon dioxide, ammonium and methane were measured. At the site with organic-rich sediments, oxygen consumption by clams measured in situ with the standard benthic chamber was variable (1.3-6.7 mmol m−2 h−1) as was total carbon dioxide production (1-9.6 mmol m−2 h−1). The observed gas and solute fluxes were attributed primarily to bivalve respiration (vesicomyids or mytilids), but microbial and geochemical processes in the sediment may be also responsible for some of variations in the deepest stations. The respiration rate of isolated vesicomyids (16.1-.25.7 µmol g−1dry weight h−1) was always lower than that of mytilids (33 µmol g−1dry weight h−1). This difference was attributed to the presence of a commensal scaleworm in the mytilids. The respiratory coefficient (QR) ≥1 indicated high levels of anaerobic metabolism. The O:N index ranged from 5 to 25, confirming that vesicomyids and mytilids, living in symbiosis with bacteria, have a protein-based food diet. Y1 - 2017/08 PB - Pergamon-elsevier Science Ltd JF - Deep-sea Research Part Ii-topical Studies In Oceanography SN - 0967-0645 VL - 142 SP - 233 EP - 243 ID - 45204 ER -