Globally, oceans are becoming increasingly acidic and hypoxic due to anthropogenic carbon emissions increasing atmospheric CO2, much of which is absorbed by the ocean. Recent research demonstrates that wastewater discharges, particularly in densely populated regions with large wastewater treatment plants, exacerbate ocean acidification and hypoxia (OAH). Excess nutrients contained in treated wastewater amplify OAH processes, negatively impacting marine life. In the United States, state and federal agencies have the authority to manage nutrient levels in treated sewage in order to protect marine ecosystems. This study includes a compilation of data on OAH and wastewater inputs across key areas—biological thresholds, wastewater plant data, treatment technology options, and policy recommendations—to provide guidance to regulators in reducing excess nutrients that contribute to OAH. A series of steps provided to coastal managers focuses on wastewater discharge as a concrete example of how to translate an emerging scientific understanding into a concrete policy and regulatory recommendation. Wastewater discharges that cause or contribute to OAH conditions in ocean-receiving waters have infrequently been regulated to reduce or eliminate impacts despite the efficacy of increasingly common treatment technologies. With a focus on the California Current Ecosystem (CCE), this study recommends implementing more stringent wastewater treatment plant regulations by moving to technology-based standards to limit nitrogen concentrations in treated sewage discharged off the coast. If implemented, these limitations would minimize wastewater contributions to OAH and reduce its harmful impacts, safeguarding coastal ecosystems and economies. The nutrient management framework outlined here can be replicated nationally using the Clean Water Act framework, or internationally using a similar regulatory framework. Sewage effluent discharges and overflows to the ocean occur in all coastal states and territories, and mitigating these nutrient contributions is a management issue for all coastal managers. In this study, we present a nutrient management framework that can be integrated into regional and national strategies to help coastal regions mitigate OAH impacts on marine ecosystems.
Van Valkenburgh M., Yettela L., Rockefeller S., Quinn J., Cusenza A., Tubaishat A., Walker E., Sheng I. & Gold M., 2026. A solution mitigating ocean acidification and hypoxia (OAH) in coastal marine ecosystems. Coastal Management, August: 1-15. doi: 10.1080/08920753.2026.2722730. Article.
0 Responses to “A solution mitigating ocean acidification and hypoxia (OAH) in coastal marine ecosystems”