Dissolved organic carbon distributions in the Bransfield and Gerlache Straits, Antarctica

• Published in: Deep Sea Research Part II: Topical Studies in Oceanography
• Main Authors: Doval, M. Dolores, Álvarez-Salgado, Xosé Antón, Castro, Carmen G., Pérez, Fiz F.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2002
• Subjects: Bransfield Strait; Gerlache; Gerlache Strait; Antarc*; Antarctica
• Online Access: http://hdl.handle.net/10261/52816; https://doi.org/10.1016/S0967-0645(01)00117-5

12 páginas, 1 tabla, 4 figuras During FRUELA’95 cruise, seawater samples were collected at the Bransfield and Gerlache Straits for the analysis of dissolved organic carbon (DOC) profiles throughout the water column. An excess of DOC probably derived from phytogenic material was observed in the upper mixed layer (UML; average: +22713 mmol Cl 1), compared to the constant concentration of refractory DOC below 400m (4474 mmol Cl 1). The average excess DOC concentration was higher than the particulate organic carbon concentration indicating the major contribution of DOC to carbon export in this area. However, large spatial variability of DOC in the upper mixed layer (52–102 mmol Cl 1) was observed: excess DOC contributed from 15% to 57% to the actual DOC concentration. Maximum average DOC concentrations in the UML were recorded in the Gerlache Strait (71 mmol Cl 1) and in the Gerlache–Bransfield confluence (80 mmol Cl 1), whereas minimum values were recorded in the Bransfield Strait (61 mmol Cl 1). Several shelf and slope stations showed a slight increase of DOC (5–10 mmol Cl 1) in the deep layer which might be related to organic matter release from the underlying sediments. Considering the net DOC release from phytoplankton, the low bacterial biomass and the reduced vertical DOC export, the DOC excess could build up in about 6 days for most of the sampling stations. The probable fate of the DOC excess is the eastwards horizontal transport by the Bransfield Current out of the study area A fellowship from the EC MAST2 project CT93-0065 allowed M.D.D. to carry out this work. X.A.A.-S. was funded by a ‘Contrato de Incorporaci !on’ of the Spanish ‘Ministerio de Educaci!on y Ciencia’. C.G.C. was funded by a contract from the EC MAS3-CT96- 0060 project. This work was financed by CICYT Contract No. ANT94-1010. Peer reviewed