Remote sensing of particle depletion by coastal suspension-feeders

Abstract

Marine bivalves have been designated ecosystem engineers owing to their capacity to control estuarine water quality, particle dynamics, and primary production. Globally, bivalves have higher production than any other cultured animal. Large populations of natural, invasive, and cultured bivalves are suggested to cause changes in coastal ecosystem function through suspension-feeding of particles and biodeposition of waste materials. Association of bivalves with particle depletion is a trophic tenet of coastal ecosystems, but there are no previous observations of this process except at small scales. Using airborne hyperspectral remote sensing, we show direct evidence of aquaculture impacts at the ecosystem scale (kilometres), documenting significant depletion of phytoplankton through a blue mussel (Mytilus edulis) farm in eastern Canada, compared with dispersion in circulation model results without mussels. Understanding of factors controlling primary production and ecosystem processes in the coastal zone is critical in light of growing reliance on this region for development and resource extraction worldwide.