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Resuspension by fish facilitates the transport and redistribution of coastal sediments
Author(s) -
Katz Timor,
Yahel Gitai,
Reidenbach Matt,
Tunnicliffe Verena,
Herut Barak,
Crusius John,
Whitney Frank,
Snelgrove Paul V. R.,
Lazar Boaz
Publication year - 2012
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.2012.57.4.0945
Subject(s) - anoxic waters , water column , groundfish , nepheloid layer , sediment , oceanography , fjord , geology , sediment trap , sediment–water interface , bottom water , hypolimnion , environmental science , inlet , geomorphology , fishery , eutrophication , ecology , fishing , fisheries management , nutrient , biology
Oxygen availability restricts groundfish to the oxygenated, shallow margins of Saanich Inlet, an intermittently anoxic fjord in British Columbia, Canada. New and previously reported 210 Pb measurements in sediment cores compared with flux data from sediment traps indicate major focusing of sediments from the oxygenated margins to the anoxic basin seafloor. We present environmental and experimental evidence that groundfish activity in the margins is the major contributor to this focusing. Fine particles resuspended by groundfish are advected offshore by weak bottom currents, eventually settling in the anoxic basin. Transmittance and sediment trap data from the water column show that this transport process maintains an intermediate nepheloid layer (INL) in the center of the Inlet. This INL is located above the redox interface and is unrelated to water density shifts in the water column. We propose that this INL is shaped by the distribution of groundfish (as resuspension sources) along the slope and hence by oxygen availability to these fish. We support this conclusion with a conceptual model of the resuspension and offshore transport of sediment. This fish‐induced transport mechanism for sediments is likely to enhance organic matter decomposition in oxygenated sediments and its sequestration in anoxic seafloors.