AAEC Oyster Assimilative Services

Enhancing Assimilative Services

Nutrient assimilative services are managed systems that enhance the aquatic ecosystem’s ability to process waste (or in the case of the Chesapeake Bay, excess nutrients). Enhancing this ability means that water quality improvements can be the achieved given the same amount of nutrients entering a water body.

While much progress has been made in the past twenty five years in reducing nutrients in the Chesapeake Bay, achieving the water quality objectives remains elusive. Past and current water quality management efforts focus primarily on reducing source (point or nonpoint) runoff. One of the objectives of this project is to explore whether and how nutrient assimilation services from oyster aquaculture can be used to achieve the water quality objectives of the Chesapeake Bay.

The filtering capabilities of oysters in oyster aquaculture is but one way this can be accomplished. Other ways the assimilative capacity of the aquatic environment can be enhanced include:

Wetlands: Forested riparian wetlands, for example, are estimated to remove 80 to 90 percent of nitrogen and phosphorus. Restoring degraded or previously drained wetlands increases the nutrient assimilative services of the aquatic environment.

BioHarvest: Harvest of other types of biomass, for example filamentalgae (at right), is a direct andquantifiable way to remove nutrients from ambient waters. Constructed systems, such as the Algal Turf Scrubber, are currently used to remove phosphorus in Florida. Harvested biomass can also be used for animal feed or to make biofuels.

Flow Augmentation: Increasing river flows during critical times can improve water quality and living resources without necessarily reducing waste inputs.