The Environmental Protection Agency’s (EPA) mission is to protect human health and the environment, which includes identifying impacts on the Nation’s coastal waters due to ocean acidification. EPA authorities under the Clean Air Act and the Clean Water Act can play an important role in addressing ocean acidification. EPA’s activities under the Clean Air Act to mitigate greenhouse gases have implications for ocean acidification because atmospheric concentrations of CO2 from anthropogenic sources are considered to be the primary driver of acidification in the open ocean and in the waters that ocean circulation brings to coastal environments. EPA and state programs under the Clean Water Act come into play in two ways: 1) acidification may affect the ability of coastal waters to support states’ applicable water quality standards; and 2) these programs help states identify and address land-based sources of pollution (e.g., nutrients) that are considered by the scientific community to be an important driver of coastal acidification.
EPA has recently developed a nationally-oriented ocean and coastal acidification program that includes applied research on ecological responses to acidification, efforts to enhance monitoring in coastal waters, and modeling to assess local drivers and forecast environmental and socioeconomic consequences of acidification. EPA’s Office of Research and Development (ORD) provides scientific support on ocean and coastal acidification to the agency’s air and water programs and regions. Prior to FY 2016, ORD ocean acidification research was primarily incidental, capitalizing on sampling opportunities that were driven by other programmatic priorities. Beginning in FY 2016, ORD is conducting targeted research on the causes and responses to acidification and hypoxia in the coastal environment, with a strong emphasis on the role of nutrients. This includes field experiments and sampling activities, laboratory investigations of the response of aquatic life to acidification in EPA’s marine laboratories, and water quality modeling studies that include carbonate chemistry.
EPA ORD is investigating the effects of nutrient enrichment on carbonate chemistry in coastal areas of the United States Northeast, Northwest, and Gulf coasts. ORD was a participant in studies of coastal acidification in the northern Gulf of Mexico; Narragansett Bay (Rhode Island), Long Island Sound (New York), and Puget Sound (Washington), some of which are continuing. In 2014, ORD began pairing seawater carbon chemistry measurements with ongoing nutrient and isotope transects in Narragansett Bay, spatially intensive nutrient sampling in Delaware Bay, and coastal shelf nutrient transects in the mid-Atlantic Bight, helping to fill a gap that lies inshore of most Federal observing programs. In 2016, ORD initiated field studies in Tillamook Estuary (Oregon) to quantify the local drivers influencing carbonate chemistry, utilizing in situ carbonate chemistry measurements and stable isotope sampling. These efforts, combined with other earlier and planned studies, are supporting EPA’s effort to incorporate carbonate chemistry into ecosystem and water quality models.
In close alignment with these field and modeling studies, the effects of coastally-relevant changes in carbonate chemistry and hypoxia on corals, crustaceans, and other aquatic life are the subject of ongoing and new experiments in EPA’s seawater laboratories in Florida, Oregon, and Rhode Island. This includes evaluation of laboratory studies as predictors of ecological effects of acidification on shellfish populations in the field (in collaboration with NOAA-funded investigators at the State University of New York – Stony Brook). ORD is extending and continuing this work through shellfish field experiments and sampling of carbonate chemistry in Narragansett Bay. In collaboration with the University of Rhode Island, ORD conducts experiments examining the effects of acidification on whole estuarine phytoplankton communities. Experiments examining the combined effects of low oxygen and low pH on aquatic life are also getting underway at ORD’s laboratory in Florida.
EPA’s Office of Water (OW) and National Center for Environmental Economics are collaborating on the development of models for valuing marine ecosystem services and assessing economic impacts from ocean acidification. Initial efforts will focus on impacts in northwestern and northeastern coastal waters of the United States.
EPA’s Region 10 (Pacific Northwest) and OW are collaborating with the Washington State Department of Ecology to develop water quality models for the Salish Sea (Washington and British Columbia, Canada). The models will provide estimates of the effect of watershed and airshed pollution on acidification (e.g., pH and aragonite saturation) throughout the marine waters of the Salish Sea.
EPA’s OW and Region 1 (New England) are collaborating with the Casco Bay Estuary Partnership (Maine) to monitor pH and pCO2 in estuarine waters. This work is being coupled with ongoing studies of nutrient concentrations to better understand how nutrients can exacerbate ocean acidification. Additionally, OW is supporting the development of a stakeholder engagement strategy by the Northeast Coastal Acidification Network.
The National Coastal Condition Assessment, one of the EPA’s National Aquatic Resource Surveys, is a statistical survey of a core suite of coastal water quality parameters conducted once every 5 years. EPA is developing standard operating procedures for collecting ocean acidification-related parameters as an add-on indicator for upcoming surveys in 2020.
Beginning in 2015, EPA’s ORD and Region 10’s Regional Applied Research Effort program paired seawater carbon chemistry measurements with spatially intensive nutrient and isotope sampling in the Snohomish River Delta (Washington) to quantify the role of anthropogenic nutrient inputs on acidification in the nearshore environment.
EPA is increasing capacity to monitor for coastal acidification by providing five National Estuary Programs (Casco Bay (Maine), Santa Monica Bay (California), Coastal Bend Bays and Estuaries (Texas), Long Island Sound Study (Connecticut/New York), and Barnegat Bay (New Jersey)) with funding for the procurement of instrumentation for high-frequency and high-precision measurement of pH and dissolved CO2.
EPA continues to engage with scientist and stakeholder networks to develop improvements in monitoring of coastal acidification. This includes partnerships in the Northeast Coastal Acidification Network, the Southeast Ocean and Coastal Acidification Network, and more locally organized networks, such as the Oregon Acidification Monitoring Network, that have spawned from workshops and educational meetings.
Beginning in 2016, ORD initiated research on nutrient enhanced coastal acidification and hypoxia with a focus on identifying local sources that may be contributing to coastal acidification in estuaries and impacts on estuarine organisms. As part of this broad effort, new experiments and field and modeling studies are planned. These include the addition of new sites to ORD’s field studies of coastal acidification and the addition of carbonate chemistry, including effects of benthic processes on pH and alkalinity, to existing ecosystem and water quality models. Modeling efforts will be supported by experiments beginning in 2016, including additional studies of biological responses to altered carbonate chemistry, as well as laboratory mesocosm and phytoplankton incubation studies in which the response of carbonate chemistry to nutrient enrichment will be evaluated. Laboratory research will also identify sensitive coastal species and establish adverse effects thresholds for acidification and hypoxia. Planned synthesis and modeling activities related to coastal eutrophication continue to provide opportunities to assess the potential for near-term mitigation of acidification through nutrient abatement programs, but formal incorporation into either non-regulatory or regulatory programs is uncertain at this time.
Research planning on the far-future time horizon at EPA is underway. Activities specifically related to ocean and coastal acidification will be identified at a later time.
Federal research activities related to acidification in the coastal environment are limited. It remains unclear whether these efforts will address the information gaps relevant to EPA protection and restoration activities. In general, these gaps exist because coverage by each agency is not well-delineated in terms of either spatial or taxonomic domain.