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Volume 55, Issue 5 p. 1881-1892
Article
Free Access

Flow effects on benthic grazing on phytoplankton by a Caribbean reef

Stephen G. Monismith

Corresponding Author

Stephen G. Monismith

Department of Civil and Environmental Engineering, Stanford University, Stanford, California

Corresponding author: [email protected]Search for more papers by this author
Kristen A. Davis

Kristen A. Davis

Department of Civil and Environmental Engineering, Stanford University, Stanford, California

Woods Hole Oceanographic Institute, Woods Hole, Massachusetts

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Gregory G. Shellenbarger

Gregory G. Shellenbarger

Department of Civil and Environmental Engineering, Stanford University, Stanford, California

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James L. Hench

James L. Hench

Department of Civil and Environmental Engineering, Stanford University, Stanford, California

Nicholas School of the Environment Marine Laboratory, Duke University, Beaufort, North Carolina

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Nicholas J. Nidzieko

Nicholas J. Nidzieko

Department of Civil and Environmental Engineering, Stanford University, Stanford, California

Woods Hole Oceanographic Institute, Woods Hole, Massachusetts

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Alyson E. Santoro

Alyson E. Santoro

Department of Civil and Environmental Engineering, Stanford University, Stanford, California

Woods Hole Oceanographic Institute, Woods Hole, Massachusetts

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Matthew A. Reidenbach

Matthew A. Reidenbach

Department of Environmental Sciences, University of Virginia, Charlottesville, Virginia

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Johanna H. Rosman

Johanna H. Rosman

Department of Civil and Environmental Engineering, Stanford University, Stanford, California

Institute of Marine Sciences, University of North Carolina at Chapel Hill, Morehead City, North Carolina

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Roi Holtzman

Roi Holtzman

The Interuniversity Institute of Marine Sciences, H. Steinitz Marine Biology Laboratory, Eilat, Israel

Section of Evolution and Ecology, University of California, Davis, California

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Christopher S. Martens

Christopher S. Martens

Department of Marine Science, University of North Carolina, Chapel Hill, North Carolina

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Niels L. Lindquist

Niels L. Lindquist

Institute of Marine Sciences, University of North Carolina at Chapel Hill, Morehead City, North Carolina

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Melissa W. Southwell

Melissa W. Southwell

Institute of Marine Sciences, University of North Carolina at Chapel Hill, Morehead City, North Carolina

Department of Chemistry, University of North Carolina, Wilmington, North Carolina

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Amatzia Geninf

Amatzia Geninf

The Interuniversity Institute of Marine Sciences, H. Steinitz Marine Biology Laboratory, Eilat, Israel

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First published: 05 August 2010
Citations: 28

Abstract

We present measurements of flows and fluxes of phytoplankton to Conch Reef, Florida, a Caribbean reef dominated by sponges and soft corals, located in 15 m of water offshore of Key Largo. Vertical profiles of chlorophyll a, a proxy for phytoplankton biomass, showed a near-bed depletion, indicating the existence of concentration boundary layers. Along with simultaneous measurements of velocity profiles, near-bed turbulence, and temperature stratification, these profiles were used to compute α, the mass transfer velocity of phytoplankton to the bed (i.e., the flux to the bed normalized by near-bed concentration). The α value ranged from -40 to +130 m d−1, with a significant linear positive relationship with shear velocity. The median value of α = 48 ± 20 m d−1 is larger than would be expected, given the observed population of filter-feeding sponges. Nonetheless, these large values of a are consistent with values found recently for another coral reef as well as for a soft bottom estuarine community. Taken as a whole, these measurements indicate that reefs with large roughness and/or energetic currents should be able to support higher biomasses of benthic organisms than would low relief reefs or reefs in sluggish waters.