On September 10-11, 2019, Dr. Suzanne Bricker (NCCOS) and Dr. Julie Rose (NMFS) led part of a workshop that explored ways to promote and implement the use of oyster habitats to remove excess nitrogen from coastal waters.
Specifically, workshop participants discussed the role that oysters play in denitrification, and how to transition the latest research on the topic to policy and management in the Chesapeake Bay and elsewhere. The workshop, organized and conducted by Dr. Robinson Fulweiler (Boston University) and hosted by Boston University's Frederick S. Pardee Center for the Study of the Longer-Range Future, was attended by 35 representatives from government, academia, and industry.
Oysters filter phytoplankton and detritus from the water column and deposit the material in bottom sediments, where microbes then remove the nitrogen in the deposited material through a process known as denitrification. By stimulating denitrification, oyster aquaculture and other oyster habitats can help remove excess nitrogen from the water that left unchecked leads to a variety of environmental problems, including hypoxia, fish kills, and harmful algal blooms.
Coastal and estuarine waters receive nitrogen from a variety of sources, including fertilizer runoff from agricultural fields and suburban lawns, runoff from large animal farms, wastewater treatment plants, stormwater from both urban and suburban areas, and atmospheric deposition directly onto an estuary and onto land within the watershed. Phosphorus is also a concern, but nitrogen remains the primary component of any comprehensive, coastal nutrient-reduction program.
The use of shellfish for coastal nitrogen remediation has been proposed in the past, but formal incorporation into nitrogen management programs is lagging. Over the course of two days, workshop attendees identified the best practices for quantifying denitrification; the practical pathways, barriers, and values (including existing public support or opposition) for incorporating oyster-mediated denitrification into nutrient trading and management programs; and opportunities to improve stakeholder communication.