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Beyond Bioextraction: The Role of Oyster-Mediated Denitrification in Nutrient Management
Citation:
Ayvazian, S., K. Mulvaney, C. Zarnoch, M. Palta, J. Reichert-Nyugen, S. McNally, M. Pilaro, A. Jones, C. Terry, AND R. Fulweiler. Beyond Bioextraction: The Role of Oyster-Mediated Denitrification in Nutrient Management. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 55(21):14457-14465, (2021). https://doi.org/10.1021/acs.est.1c01901
Impact/Purpose:
Removal techniques include improved wastewater treatment infrastructure and applying best management practices for fertilizer application (Riemann et al. 2016). While reductions in nitrogen loading to coastal ecosystems are critical to reducing over-enrichment, they do not effectively eliminate excess nitrogen and associated ecological problems altogether from coastal areas, and other tools are still needed. The challenges associated with successfully implementing source control programs has led to the consideration of less costly and more immediate mechanisms for mitigating N loading. Shellfish can provide N removal through bioextraction (harvest) and via the enhancement of denitrification (the microbial conversion of reactive N to inert di-nitrogen (N2) gas). This paper is intended to provide stakeholders and decision-makers with a basic understanding of oyster mediated denitrification, examples of its use for potential incorporation into future nitrogen management programs, and areas of further study.
Description:
Recently, interest has grown in using oyster-mediated denitrification resulting from aquaculture and restoration as mechanisms for reactive nitrogen (N) removal. To date, short-term N removal through bioextraction has received the most management interest, but there is a growing body of research that has shown oysters can also mediate the long-term removal of N through denitrification (the microbial conversion of reactive N to relatively inert dinitrogen (N2) gas). Oyster suspension feeding and ammonium release via waste and deposition of organic matter to the sediments can stimulate nitrification–denitrification near oyster reefs and aquaculture sites. Oysters also harbor a diverse microbial community in their tissue and shell promoting denitrification and thus enhanced N removal. Additionally, surface areas on oyster reefs provide a habitat for other filter-feeding macrofaunal communities that can further enhance denitrification. Denitrification is a complex biogeochemical process that can be difficult to convey to stakeholders. These complexities have limited consideration and inclusion of oyster-mediated denitrification within nutrient management. Although oyster-mediated denitrification will not be a standalone solution to excess N loading, it may provide an additional management tool that can leverage oyster aquaculture and habitat restoration as a N mitigation strategy. Here, we provide an overview of the biogeochemical processes involved in oyster-mediated denitrification and summarize how it could be incorporated into nutrient management efforts by various stakeholders.
URLs/Downloads:
DOI: Beyond Bioextraction: The Role of Oyster-Mediated Denitrification in Nutrient Management
https://pubs.acs.org/doi/abs/10.1021/acs.est.1c01901