TY - JOUR
T1 - Resuspension by fish facilitates the transport and redistribution of coastal sediments
AU - Katz, Timor
AU - Yahel, Gitai
AU - Reidenbach, Matt
AU - Tunnicliffe, Verena
AU - Herut, Barak
AU - Crusius, John
AU - Whitney, Frank
AU - Snelgrove, Paul V.R.
AU - Lazar, Boaz
N1 - Publisher Copyright:
© 2012, by the Association for the Sciences of Limnology and Oceanography, Inc.
PY - 2012/7
Y1 - 2012/7
N2 - Oxygen availability restricts groundfish to the oxygenated, shallow margins of Saanich Inlet, an intermittently anoxic fjord in British Columbia, Canada. New and previously reported 210Pb 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.
AB - Oxygen availability restricts groundfish to the oxygenated, shallow margins of Saanich Inlet, an intermittently anoxic fjord in British Columbia, Canada. New and previously reported 210Pb 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.
UR - http://www.scopus.com/inward/record.url?scp=84897478961&partnerID=8YFLogxK
U2 - 10.4319/lo.2012.57.4.0945
DO - 10.4319/lo.2012.57.4.0945
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AN - SCOPUS:84897478961
SN - 0024-3590
VL - 57
SP - 945
EP - 958
JO - Limnology and Oceanography
JF - Limnology and Oceanography
IS - 4
ER -