MEPS 673:29-41 (2021)  -  DOI: https://doi.org/10.3354/meps13803

ABSTRACT: Filter-feeders play an important role in regulating nutrient availability in coastal systems, with important implications for phytoplankton community composition, primary production, and food web structure. The role of filter-feeding bivalves in the nitrogen and phosphorus cycles is relatively well established, but their impact on coastal silicon (Si) cycling remains poorly understood. To help reduce this uncertainty, we quantified rates of Si recycling and the size of various Si pools at an oyster (Crassostrea virginica) farm. We found that oysters drive rapid recycling of dissolved Si (DSi) to the water column, primarily by altering rates of sediment Si flux. Sediments beneath oyster aquaculture recycled DSi to the water column at more than twice the rate (2476.06 µmol DSi m^-2 h^-1) of nearby bare sediments (998.75 µmol DSi m^-2 h^-1). Oysters consume DSi at a low rate (-0.06 µmol DSi ind.^-1 h^-1), and, while we were unable to determine the fate of that Si, we hypothesize that at least some of it may be stored in the shell and tissue, which are both small Si pools (0.55 and 0.13% Si by mass respectively). Si held in oysters is removed from the system when oysters are harvested, but this removal is small compared to oyster-mediated enhancements in sediment Si recycling. In a broader context, coastal systems with larger oyster populations are likely to have a more rapid Si cycle, with more Si available to primary producers in the water column than those with no oysters.

KEY WORDS: Oyster · Silicon · Aquaculture · Coastal biogeochemistry

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Cite this article as: Ray NE, Al-Haj AN, Maguire TJ, Henning MC, Fulweiler RW (2021) Coastal silicon cycling amplified by oyster aquaculture. Mar Ecol Prog Ser 673:29-41. https://doi.org/10.3354/meps13803 Export citation Share:    Facebook - - linkedIn