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Data from: How are coastal benthos fed?

This paper is available in a repository.
This paper is available in a repository.

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Preprint: policy unknown
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Postprint: policy unknown
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Published version: policy unknown

Abstract

Water movement can influence the distribution of benthic suspension feeders, in part, by increasing food delivery; however, the impact of advective transport and turbulent diffusion on organic matter flux to nearshore benthic communities is not well quantified, and sediment trap-derived estimates of food delivery in these systems are often lower than what is required to support observed benthic respiration. In this study we used two naturally occurring daughter/parent radionuclide pairs (234Th/238U and 90Y/90Sr) to measure particulate organic carbon (POC) and particulate phosphorus flux from the water column to the nearshore bottom of Lake Michigan, where quagga mussel tissue biomass on rock surfaces was assessed at 117 ± 39 g DW m-2. Estimates of carbon respiration and total phosphorus excretion by mussels were derived from coincident benthic chamber measurements of O2 consumption and total dissolved phosphorus excretion. Although mussel carbon respiration and phosphorus excretion fluxes were concordant with water column nutrient fluxes, estimates of POC flux to the lakebed and mussel carbon respiration were up to six times higher than published estimates of local primary production. We found that advective onshore transport and vertical convective mixing increased POC flux to the nearshore benthos by a factor of ~15 over offshore trap-derived estimates of POC flux. From these results, we hypothesize that high benthos population densities are related to an edge effect created when the dominant mechanism of particle delivery transitions from gravitational settling to convection.