The occurrence of hypoxia, or low dissolved oxygen, is increasing in coastal waters worldwide and represents a significant threat to the health and economy of our Nation’s coasts and Great Lakes. This report discusses the causes and impacts of hypoxia, means of addressing the problem, and federal research on the issue.
Hypoxia is a major contributor to the decline of coastal water quality observed in recent decades, and its extent has been expanding. It is part of the broader issue of nutrient-driven eutrophication. Eutrophication is also linked to increased HABs, loss of seagrasses, and other impacts on coastal ecosystems. For eutrophic ecosystems, concerted and coupled research and management efforts, along with stakeholder support, will be needed to rigorously identify, quantify, and implement nutrient reduction strategies that are effective and achievable. Furthermore, for systems such as the Oregon shelf where hypoxia is driven primarily by natural processes linked to variations in climate, improved scientific understanding will provide insight into future impacts of climate change on similar ecosystems. Moreover, knowledge gained will be important for developing forecasts of the extent and severity of low dissolved oxygen, which will help managers mitigate the impacts of hypoxia.
If properly planned and executed, adaptive management of nutrient inputs will lead to significant reductions in hypoxia. However, if current practices are continued, the expansion of hypoxia in coastal waters will continue and increase in severity, leading to further impacts on marine habitats, living resources, economies, and coastal communities.