Title Shelf erosion and submarine river canyons; implications for deep-sea oxygenation and ocean productivity during glaciation
Author Tsandev, I.; Rabouille, C.; Slomp, C.P.; van Cappellen, P.
Author Affil Tsandev, I., Utrecht University, Department of Earth Sciences- Geochemistry, Utrecht, Netherlands. Other: CNRS, Laboratoire des Sciences du Climat et de l'Environnement, France; Georgia Institute of Technology
Source Biogeosciences, 7(6), p.1973-1982, . Publisher: Copernicus GmbH on behalf of the European Union, Katlenburg-Lindau, International. ISSN: 1726- 4170
Publication Date 2010
Notes In English. Published in Biogeosciences Discussions: 2 February 2010, http://www.biogeosciences- discuss.net/7/879/2010/bgd-7-879-2010.html; accessed in Apr., 2011; abstract: doi:10.5194/bg-7-1973-2010. 49 refs. GeoRef Acc. No: 310433
Index Terms erosion; geochemical cycles; glaciation; ocean environments; ocean bottom; oxygen; Pleistocene; sedimentation; carbon; Cenozoic; continental shelf; cycles; deep-sea environment; deep-sea sedimentation; depletion; geochemical cycle; glacial environment; interglacial environment; last glacial maximum; marine environment; marine sedimentation; ocean floors; organic carbon; paleogeography; particulate materials; phosphorus; Quaternary; sea-level changes; submarine canyons
Abstract The areal exposure of continental shelves during glacial sea level lowering enhanced the transfer of erodible reactive organic matter to the open ocean. Sea level fall also activated submarine canyons thereby allowing large rivers to deposit their particulate load, via gravity flows, directly in the deep-sea. Here, we analyze the effects of shelf erosion and particulate matter re- routing to the open ocean during interglacial to glacial transitions, using a coupled model of the marine phosphorus, organic carbon and oxygen cycles. The results indicate that shelf erosion and submarine canyon formation may significantly lower deep-sea oxygen levels, by up to 25%, during sea level low stands, mainly due to the supply of new material from the shelves, and to a lesser extent due to particulate organic matter bypassing the coastal zone. Our simulations imply that deep-sea oxygen levels can drop significantly if eroded shelf material is deposited to the seafloor. Thus the glacial ocean's oxygen content could have been significantly lower than during interglacial stages. Primary production, organic carbon burial and dissolved phosphorus inventories are all affected by the erosion and rerouting mechanisms. However, re-routing of the continental and eroded shelf material to the deep-sea has the effect of decoupling deep- sea oxygen demand from primary productivity in the open ocean. P burial is also not affected showing a disconnection between the biogeochemical cycles in the water column and the P burial record.
URL http://www.biogeosciences.net/7/1973/2010/bg-7-1973-2010.pdf
Publication Type journal article
Record ID 65007164