The primary cause of ocean acidification is an increase in carbon dioxide in the oceans that is caused by increasing levels of carbon dioxide in the atmosphere. Human activities—including the burning of fossil fuels, cement production, deforestation, and agriculture—release carbon dioxide into the atmosphere. Since the 1700s, atmospheric carbon dioxide concentrations have risen from approximately 280 parts per million to approximately 400 parts per million (see fig. 1). As the carbon dioxide concentration in the atmosphere increases, more carbon dioxide is absorbed by the oceans, where it reacts with water to form carbonic acid, most of which separates to form a hydrogen ion and a bicarbonate ion.the pH of the water. The resulting increase in hydrogen ion concentration is what lowers Since the 1700s, the average surface ocean pH has decreased from about 8.2 to 8.1, a change representing an approximately 26 percent increase in ocean acidity. At the current rate of carbon dioxide emissions, scientists project that, by 2100, the average pH of the ocean surface will drop to between 7.9 and 7.7. Such a drop would correspond to a rise in acidity of approximately 100 percent to 200 percent over preindustrial levels. Moreover, the current rate of acidification is believed to be faster than at any point in at least the last 20 million years. In addition to increasing acidity, the higher levels of carbon dioxide in the oceans also cause chemical reactions that reduce what is known as the “saturation state” of calcium carbonate minerals such as aragonite and calcite. As the saturation state of these carbonate minerals decreases, some marine organisms will need to use more energy to acquire the carbonate ions needed to build shells or skeletons. In addition, when the saturation state drops below 1 (i.e., undersaturated), then structures such as animal shells that are made of carbonate minerals may begin to dissolve. As the oceans absorb more carbon dioxide, scientific models predict that the saturation state of many surface waters, including areas supporting rich fisheries, will continue to decline (see fig. 2). The carbonate mineral saturation state is affected by several other factors in addition to carbon dioxide. For example, the temperature, pressure, and salinity of the ocean water at a particular location affects the saturation state. As a result, the latitude of a particular ocean location, the depth of the water there, and the extent to which it receives freshwater input from rivers all play a role in determining the saturation state. In general, saturation state is highest in warm, shallow, saline waters. Therefore, the Arctic Ocean, which has colder water and receives large amounts of fresh water from rivers and melting ice, and deepwater environments generally have naturally lower saturation states. Biological processes also affect the pH and saturation state of the oceans. During the day, marine plants, including phytoplankton and seagrasses, use sunlight and carbon dioxide to create and store energy, a process known as photosynthesis.dioxide levels, thus increasing the pH and carbonate mineral saturation states of the upper reaches of the ocean. Conversely, as organic (i.e., This activity reduces carbon carbon-based) matter decomposes, carbon dioxide is released back into the water, thus decreasing pH. Some of the decomposing organic matter sinks into deeper water, which, over time, has contributed to deeper waters naturally being lower in pH and having lower saturation states with respect to calcium carbonate minerals. The effect of biological processes on ocean chemistry also means that pH and saturation states vary more widely in coastal and estuarine waters than in the open ocean. Coastal and estuarine areas have high concentrations of plant life and receive freshwater inputs from rivers, factors that influence ocean chemistry. The resulting variation may occur both daily, because of the effect of photosynthesis, and seasonally, due to changes in the amount of available solar energy and of river flows. Although the primary cause of ocean acidification is the increase in global atmospheric carbon dioxide emissions, other factors also contribute to acidification, particularly in coastal and estuarine areas. In particular, increased nutrient pollution (e.g., of nitrate, phosphate, and iron) from agricultural fertilizers and from septic systems and sewage treatment plants results in higher than normal levels of biological growth, a condition known as “eutrophication.” In the short run, the faster growth of plants such as phytoplankton may raise the pH of coastal and estuarine waters by consuming carbon dioxide in the water and releasing oxygen. In the long run, however, when plants die, the decomposition process releases carbon dioxide and may lower the pH, sometimes substantially.addition, local sources of air pollution may also contribute to acidification in coastal and estuarine areas. For example, in addition to releasing carbon dioxide into the atmosphere, the burning of fossil fuels releases other gases such as nitrogen oxides and sulfur oxides that can be In deposited on coastal and estuarine waters, or on streams and rivers flowing into coastal waters, lowering the pH. Ocean acidification could have a variety of potentially significant effects on marine species, ecosystems, and coastal communities, according to the six summary reports we reviewed. However, the scientific understanding of these effects is still developing, and there remains uncertainty about their scope and severity. Calcifying species—that is, species that produce shells and skeletons composed of calcium carbonate minerals—are expected to be among the most vulnerable types of species to ocean acidification. Not all calcifying species, however, are expected to respond the same way to reductions in carbonate ion concentrations resulting from ocean acidification, and some are expected to be more at risk than others. For example: Mollusks. Ocean acidification could negatively affect the survival and growth of some mollusks—including bivalve species such as oysters and mussels—by making calcification more difficult, according to the summary reports we reviewed. Among bivalve species that have displayed a negative response to ocean acidification, larval and juvenile bivalves may be more susceptible to harm than adult bivalves. For example, according to a 2013 study of Pacific oyster (Crassostrea gigas) larvae, during the period of initial shell formation in the early days of an oyster’s life, oyster larvae rely primarily on the energy derived from their egg reserves to build their shells because the oysters have not yet developed their primary feeding organ. When exposed to an environment with a lower carbonate ion concentration, however, the larvae have to expend more energy to build their shells. This increased energy expenditure during the period of initial shell formation makes it more difficult for the oysters to develop their feeding organs and reduces the probability that the oysters will survive. Figure 3 compares Pacific oyster larvae raised in acidified conditions (characterized by reduced pH levels and carbonate mineral saturation states) with those raised under more favorable ocean conditions. The figure shows that the Pacific oyster larvae raised under acidified conditions experienced impaired shell development, and their shells had various deformities compared with the larvae raised under more favorable conditions. Even in instances where oysters are able to survive their larval stage under acidified conditions, the greater energy required to produce their shells could contribute to decreased growth in later life stages. For example, a 2012 study examined the effects of ocean acidification on the Olympia oyster (Ostrea lurida) and found that larvae raised in water with a low pH (7.8) exhibited a slower shell growth rate that continued even once the oysters became juveniles. Not all mollusk species have responded negatively to ocean acidification conditions in research experiments, according to the reports we reviewed. One of the reports noted that roughly half of the mollusk species examined have displayed no effects from ocean acidification, and that a few mollusk species have displayed positive effects. For example, one study cited in the report found that mortality rates declined for juveniles of one clam species (Ruditapes decussatus) kept in seawater with artificially lowered pH levels compared with juveniles kept in seawater at higher pH levels. Corals. Corals were also identified in the summary reports we reviewed as being among the calcifying species most at risk for harm from ocean acidification. Ocean acidification may make it more difficult for some corals to grow their skeletons due to the reduced carbonate ion concentration and may affect coral reproduction. In addition, ocean acidification could potentially increase the rate at which coral skeletons dissolve and erode. However, not all coral species are expected to be negatively affected by ocean acidification, according to the reports we reviewed. and Reduced pH: Variable Responses to Ocean Acidification at Local Scales?” Journal of Experimental Marine Biology and Ecology, vol. 396 (2011). could cause behavioral changes in some fish species by interfering with the functioning of sensory systems, such as the ability to smell. Such changes in sensory systems could, in turn, produce behavioral changes that alter predator-prey interactions, among other things. For example, one study cited in two of the summary reports we reviewed found that clownfish larvae raised in an elevated carbon dioxide environment became attracted to the scent of predators rather than avoiding this odor, whereas clownfish larvae raised under carbon dioxide conditions similar to the current environment exhibited a strong avoidance to the odor of predators. Similarly, another study found that juvenile damselfish and cardinalfish living in ocean waters with naturally high carbon dioxide levels—caused by nearby volcanic vents that emit carbon dioxide and lower the pH of surrounding waters—were attracted to predators’ odors and exhibited bolder behavior than fish from ocean waters that were unaffected by the volcanic vents.behavioral changes cause species to be at a higher risk from predators, such changes could potentially lead to increased mortality rates for affected species. However, according to the reports we reviewed, the extent to which other fish species—including commercially important fish such as salmon—are vulnerable to behavioral effects caused by changes in the functioning of sensory systems due to ocean acidification is unclear. To the extent these types of Another way in which ocean acidification could affect marine species is by enhancing photosynthetic processes in ocean waters with elevated carbon dioxide concentrations. In particular, the possibility that some marine plant species, such as certain seagrasses, could experience increased photosynthesis and growth was highlighted by the summary reports we reviewed as a primary example of the potential for ocean acidification to benefit some species. However, this type of beneficial effect appears to be variable among photosynthetic species, and the net effect of ocean acidification on some marine photosynthetic species could be negative. For example, the reports we reviewed noted that marine macroalgae (seaweeds) are expected to display a diverse response to ocean acidification, in part because macroalgae include a mix of calcifying and noncalcifying species. Since ocean acidification may reduce calcification abilities, the growth of calcifying macroalgae may be compromised under future ocean acidification conditions even if these species experience increased photosynthesis, whereas the growth of noncalcifying macroalgae is more likely to be enhanced. For instance, in a study cited in one of the reports we reviewed, researchers examined the abundance of calcifying versus noncalcifying species of macroalgae near volcanic vents in the ocean and found that the abundance of noncalcifying macroalgae increased as the pH declined, whereas the abundance of calcifying macroalgae decreased. The presence of other stressors in the marine environment—such as warming ocean temperatures, hypoxia, and pollution—were highlighted in the summary reports we reviewed as factors that make it difficult to determine how ocean acidification will affect different species. Knowledge about the simultaneous effects of ocean acidification and these other stressors on species is incomplete, but these stressors could potentially exacerbate the effects of ocean acidification. For example, a recent study found that the combined effects of hypoxia and ocean acidification were more severe on early life stage bivalves than would be expected for either stressor on its own. reviewed stated that ocean acidification may compromise the resiliency of corals to the other threats they face, such as increased ocean temperatures, by, for example, causing some coral species to be more susceptible to coral bleaching. Hypoxia is a condition where waters have low dissolved oxygen concentrations. Gobler et al., “Hypoxia and Acidification Have Additive and Synergistic Negative Effects on the Growth, Survival, and Metamorphosis of Early Life Stage Bivalves,” PLoS ONE, vol. 9, issue 1 (January 2014). effects on different species is the potential for species to adapt to changes in ocean chemistry. In this context, adaptation refers to the ability of a species to evolve over successive generations to become better suited to its habitat, which in the case of ocean acidification would mean a reduced carbonate ion, lower pH ocean environment. If species are successful in adapting genetically to these changing conditions, it could be possible for them to avoid some of the negative effects that might otherwise occur from ocean acidification. For example, one of the summary reports we reviewed noted that it might be possible for some coral species to evolve a mechanism that would enable them to calcify at normal rates even in waters with lower carbonate ion concentrations, although this type of adaptation has not been documented in corals. Moreover, since the changes to ocean chemistry currently taking place are occurring rapidly on evolutionary timescales, the reports we reviewed stated that it is unknown whether species will be able to adapt to the expected rate and magnitude of ocean acidification’s changes. The potential for ocean acidification to alter marine food webs was identified in the reports we reviewed as one of the most significant ecosystem-level effects that could result from ocean acidification.difficult to predict exactly how a change to a species in one part of a food web will affect other species, but if ocean acidification were to negatively affect species at lower levels in a food web, it is possible those negative effects could lead to broader ecosystem effects involving species at higher levels. For example, pteropods—a type of small calcifying sea snail—represent an important component of some marine food webs and were highlighted as potentially being vulnerable in several of the summary reports we reviewed. Among other things, pteropods are an important food source for salmon and other animals such as seabirds and whales. Some pteropods’ calcification and growth rates decline as pH levels decrease, and their shells can partially dissolve under acidified conditions (see fig. 4). For example, a recent study found a strong relationship between increased shell dissolution in one pteropod species (Limacina helicina) and reduced carbonate ion concentrations off the It is West Coast of the United States.acidification on pteropod populations is unknown, but if pteropod populations were to decline, there could be cascading effects through the food webs of some marine ecosystems—including those supporting economically important fisheries such as salmon. The effects of ocean acidification on marine species and ecosystems may affect the goods and services they provide, which may cause economic disruptions, according to the summary reports we reviewed.example: Shellfish harvest and aquaculture. Shellfish harvest is the most valuable sector of the commercial fishing industry in the United States, accounting for 53 percent of U.S. commercial fishing landings and valued at approximately $2.7 billion in 2012, according to NOAA. In addition, NOAA reported that the approximate value of shellfish produced by aquaculture in the United States in 2011 was $422.0 million. Potential declines in the health of shellfish populations from ocean acidification could negatively affect both shellfish harvest and aquaculture. Oyster aquaculture has already experienced significant disruption in the Pacific Northwest. The Washington State Blue Ribbon Panel on Ocean Acidification reported that, between 2005 and 2009, acidified conditions killed billions of oyster larvae at two of the three primary hatcheries that provide Pacific oysters to growers in the Northwest, disrupting the industry throughout the region. A representative from one of the affected hatcheries said that the hatcheries—assisted by federal and state agency efforts to improve monitoring of ocean chemistry—have been able to change the systems that bring seawater into their hatcheries to avoid particularly low pH levels. Nonetheless, both the hatchery and agency officials we spoke with expressed concern that future ocean conditions could exceed the hatcheries’ ability to adapt. Similarly, crab harvest constitutes an important component of the fishing industry in Alaska, and recent research suggests that some juvenile crab species are less able to survive in lower pH waters, which could lead to declines in an industry that, in the Bering Sea and Aleutian Islands, harvested crabs valued at approximately $245 million annually, on average, from 2008 through 2012. Finfish harvest. As with shellfish, potential future declines in the health of finfish populations from ocean acidification could negatively affect their harvest, which NOAA reported was valued at approximately $2.4 billion in 2012. Finfish—including those that are important components of commercial marine fisheries such as salmon, pollock, and cod—may be directly affected by ocean acidification. In addition, if ocean acidification changes marine food webs or habitat—such as coral and oyster reefs—that are important to finfish reproduction, growth, and survival, the finfish industry could also be affected. Tourism and recreation. Marine ecosystems also generate important economic and social benefits from tourism and recreation that may be at risk from ocean acidification. Recreational saltwater fishing contributed approximately $17.5 billion to the U.S. gross domestic product in 2011, including money spent on food, lodging, and transportation, according to an estimate by an industry trade association. In addition, NOAA has reported that millions of people visit coral reefs to dive, snorkel, and sightsee, contributing significantly to local economies in Florida, Hawaii, and many U.S. territories. If ocean acidification leads to declines in the health of marine ecosystems, the economic and social benefits from marine tourism and recreation could also decline. Storm protection. Certain marine ecosystems, such as coral and oyster reefs, help protect coastal communities from flooding caused by hurricanes and other storms, thereby reducing the damage and social disruption that can accompany such storms. If ocean acidification harms such ecosystems, the storm protection benefits they provide could decline. The expected effects of ocean acidification may disproportionately affect some regions and communities that are strongly connected economically and/or culturally to the goods and services provided by marine ecosystems. For example: Fisheries are important in both New England and on the West Coast, but one economic study estimated that potential revenue losses due to ocean acidification would be four times higher in New England, due to the significance of the shellfish harvest to the local economy. Moreover, some communities may be disproportionately affected. For example, in recent years, New Bedford, Massachusetts, has been the U.S. port with the highest value of fish landed, largely due to its scallop fishery. The study concluded that a decline in scallop revenue due to ocean acidification would further depress a community that has struggled economically. Similarly, shellfish aquaculture operations are major employers in Pacific and Mason counties in Washington State; consequently, if ocean acidification harms shellfish aquaculture, it could have a significant economic impact on these communities. Harvesting fish and shellfish is an important element in many tribal communities for economic, dietary, and cultural reasons. Many tribal communities in Washington State view ocean acidification both as an economic issue and, because salmon and shellfish are important ceremonial foods, as a threat to their identity and cultural survival, according to one of the summary reports we reviewed.In some coastal communities, harvesting marine resources is not just an economic activity but “a way of life.” For example, commercial fishing not only provides household income but also is intertwined with how families, generations, and the community as a whole interact with each other and with nature, according to one of the summary reports we reviewed. Federal agencies have taken a variety of steps to implement FOARAM and to support the federal response to ocean acidification more broadly.However, the agencies have yet to complete other FOARAM requirements. The Subcommittee on Ocean Science and Technology implemented the FOARAM requirement to establish an interagency working group and subsequently delegated responsibility for developing the required research and monitoring plan to the working group. NOAA, the National Science Foundation, and NASA—the three agencies required by FOARAM to take specific actions related to ocean acidification outside of the working group—have also taken steps to implement those requirements. In addition, the other federal agencies that are part of the interagency working group have taken steps to support the federal response to ocean acidification (see app. I). The agencies participating in the interagency working group have estimated that from fiscal year 2010, the fiscal year after FOARAM was enacted, through fiscal year 2013 they have spent approximately $88 million ($22 million annually, on average) on activities directly related to ocean acidification (see app. II). The interagency working group on ocean acidification is composed of senior representatives from 11 federal agencies involved in responding to ocean acidification. FOARAM specified five agencies—NOAA, the National Science Foundation, NASA, U.S. Fish and Wildlife Service, and U.S. Geological Survey—as well as “other federal agencies as appropriate,” to be part of the working group. In addition to the agencies specified in the act, as of August 2014, six agencies with missions that could be affected by ocean acidification—the Bureau of Ocean Energy Management, Department of Energy, Department of State, Environmental Protection Agency (EPA), U.S. Department of Agriculture, and U.S. Navy—have also joined the working group.interagency working group, which is chaired by NOAA and vice-chaired by NASA and the National Science Foundation, has met approximately quarterly. Since January 2010, the One of the primary tasks of the interagency working group has been to guide the development of a research and monitoring plan, which FOARAM required to be developed by March 2011. was approved by the Office of Science and Technology Policy and released to the public in March 2014, outlines key efforts identified by the interagency working group that need to be taken over the next 10 years to advance the nation’s understanding of, and ability to respond to, ocean acidification. The working group has also issued two reports, required by FOARAM, describing federal actions related to ocean acidification research and monitoring. The first report was required to be issued by March 2010 and the second to be issued two years later. The first report was issued in March 2011 and the second in 2013. Interagency Working Group on Ocean Acidification, Initial Report on Federally Funded Ocean Acidification Research and Monitoring Activities and Progress in Developing a Strategic Plan (Washington, D.C.: March 2011), and Second Report on Federally Funded Ocean Acidification Research and Monitoring Activities and Progress on a Strategic Research Plan (Washington, D.C.: 2013). acidification on species and ecosystems is needed to determine the magnitude and extent of acidification and to advance research. The plan’s goals include evaluating existing ocean monitoring systems that could be expanded to monitor ocean acidification (e.g., by adding new sensors) and identifying regions where new monitoring systems may be warranted. Modeling to predict changes in ocean chemistry and impacts on marine ecosystems and organisms. The plan stated that models are needed to help predict likely changes to ocean chemistry and marine ecosystems resulting from ocean acidification and to provide information that can inform resource management decisions (e.g., decisions related to managing fisheries). The plan’s goals include developing and improving models that can be used to predict direct and indirect effects of ocean acidification on culturally, economically, and ecologically important species. Technology development and standardization of measurements. The plan stated that new technologies and standardization of measurements are required to support research and monitoring. The plan’s goals include (1) developing standardized methodologies for measuring how plants and animals respond to ocean acidification and (2) improving the accuracy and affordability of monitoring equipment. Assessment of socioeconomic impacts and development of adaptation and mitigation strategies. The plan stated that better understanding the social and economic effects of ocean acidification can help inform discussions about how society can adapt to it and mitigate its causes. The plan’s goals include developing models to estimate the economic effects of ocean acidification and assisting national, state, and local governments and businesses to develop adaptation plans. Education, outreach, and engagement. The plan recognized the importance of effective outreach and education to improve awareness of the potential effects of ocean acidification and to engage stakeholders (e.g., nongovernmental organizations, fishing industry representatives, and natural resource managers) and the public in a discussion of policy options for responding to acidification. The plan’s goals include engaging federal and academic partners to develop and implement outreach programs. Data management and integration. The plan stated that the success of the federal response to ocean acidification depends on effective data management and recognized that it is critical that data be shared and integrated across organizational boundaries and blended from diverse information systems. The plan’s goals include establishing a program or office to manage ocean acidification data collection and determining how the data will be archived and accessed. NOAA formally established an ocean acidification program, required by FOARAM, in May 2011. The program is staffed by a director and two to three other staff and is overseen by an executive board consisting of senior officials from the four NOAA offices involved in ocean acidification. Because of the number of NOAA offices involved, a primary responsibility of the ocean acidification program is to coordinate all of NOAA’s actions related to ocean acidification. It also coordinates and collaborates with other agencies, stakeholders, and researchers, both within and outside of the United States. NOAA ocean acidification program officials estimated they spent approximately $6 million annually, on average, between fiscal year 2011 and fiscal year 2013, to support the types of activities envisioned in the interagency working group’s research and monitoring plan. Program officials estimated that the program has directed about 50 percent of its funds towards ocean acidification monitoring and about 20 percent toward research on species’ responses to acidification, with the remainder aimed at improving scientific models of acidification, data management, and other activities. Examples of program actions include: Improving ocean acidification monitoring capabilities. NOAA has taken steps to address FOARAM’s requirement to establish a long- term ocean acidification monitoring program. For example, the agency is working with state agencies and regional stakeholders, including regional associations of the Integrated Ocean Observing System, to identify (1) locations where additional monitoring capabilities would be useful and (2) opportunities for adding ocean acidification monitoring equipment to locations where other monitoring equipment already exists. NOAA’s ocean acidification program, often in conjunction with state agencies and others, has also helped fund deployment of new monitoring assets in some locations, but the director of the program told us that funding levels have hindered the agency’s ability to further expand monitoring networks. NOAA has also taken steps to address FOARAM’s requirement to coordinate its monitoring activities with international partners. For example, NOAA, along with international partners and others, has sponsored workshops to, among other goals, develop consensus within the international scientific community on the chemical, physical, and biological variables that an ocean acidification monitoring network should measure and on data collection protocols to ensure appropriate data quality and comparability.hindering development of a monitoring network, including, for example, limitations in the quality of existing monitoring equipment. crab or scallop populations might have on fishing communities in Alaska or New England, respectively. To respond to FOARAM’s requirements for the agency, the National Science Foundation established ocean acidification research as a specific agency focus for fiscal years 2010 through 2014. During these years, the agency issued four solicitations requesting scientists to submit research proposals related to ocean acidification. Overall, from fiscal year 2010 through fiscal year 2013, the National Science Foundation selected approximately 50 proposals to receive funding and directed an estimated $11 million annually, on average, to ocean acidification research. The projects selected for funding covered diverse aspects of ocean acidification, including (1) changes to ocean chemistry in a variety of locations; (2) effects on the biological, chemical, and physical processes of a variety of marine species; and (3) how the effects on species might affect different ecosystems. Funded projects included examinations of: Changes to ocean chemistry during a previous geological period, research that could provide insights into the short- and long-term impacts of human-caused carbon dioxide emissions on surface ocean pH and carbonate chemistry. The effects of elevated carbon dioxide levels in the ocean on a pteropod species (Limacina retroversa) in the Gulf of Maine that is preyed on by commercially important fish species. The effects of elevated ocean carbon dioxide levels on the growth, calcification, and physiology of corals and other species inhabiting a remote coral reef in the Pacific Ocean. The National Science Foundation has reported that its most recent solicitation, issued in fiscal year 2014, is expected to be the final one requesting research proposals specifically for ocean acidification. A senior agency official told us that the agency would continue to fund ocean acidification research in the context of its overall research program, although likely at a lower level of funding. The official also said that it is common for the agency to focus research on a specific issue for a few years and then reintegrate that issue into its overall program. NASA maintains a system of satellites that collects data on many aspects of the Earth, including on aspects of the global carbon cycle and ocean ecology that are relevant to ocean acidification, and has made its data available to other researchers. It also has provided funding to outside researchers to study ocean acidification. Between 2007 and 2012, the agency issued approximately 10 solicitations for research and provided funding for four research projects, according to an agency official. For example, one project funded by NASA is examining the effects of ocean acidification on ocean chemistry and phytoplankton photosynthesis in the Arctic Ocean. The agencies have yet to implement the following FOARAM requirements: (1) establish each agency’s role in implementing the research and monitoring plan and outline the budget requirements for implementing the plan, (2) establish an ocean acidification information exchange, and (3) develop adaptation and mitigation strategies to conserve marine organisms and ecosystems. The agencies completed the research and monitoring plan required by FOARAM, but that plan does not include all of the required elements. Specifically: FOARAM requires the research and monitoring plan to set forth the role of each agency in implementing it, but the plan does not do so. Interagency working group officials told us they expect that additional information on the roles and responsibilities of the agencies will be provided in an implementation plan, which the working group has begun developing, according to its chair. Our previous work on interagency collaborative efforts has found that clarifying the roles and responsibilities of the participating agencies is an important factor in the success of such efforts. Until the specific roles and responsibilities of the agencies are clarified, it will be difficult for the working group and its member agencies to make progress in implementing important actions called for in the research and monitoring plan. FOARAM also requires that the research and monitoring plan outline the budget requirements for each agency to implement the plan’s research, monitoring, and assessment activities, but the plan does not include them. According to the previous chair of the working group, a high-level estimate of the federal funding needed for each agency to implement the research and monitoring plan was developed during the early drafting of the plan, but this information was excluded from the final plan at the direction of the Office of Management and Budget. Many officials and stakeholders we interviewed said that the level of funding directed to ocean acidification to date has been insufficient given the potential scope and severity of effects expected in the future. Some of the officials expressed concern that excluding budget estimates from the research and monitoring plan has prevented the agencies and Congress from accurately understanding the funding needed to implement the plan and how it compares with current funding levels. Developing and disclosing estimates of the needed funding may be particularly important for efforts involving multiple agencies. In our previous work on interagency collaborative efforts, we reported that effective interagency collaborative efforts require, among other things, the identification of the types and level of resources needed to implement the planned activities. FOARAM requires the Subcommittee on Ocean Science and Technology to establish or designate an ocean acidification information exchange. The subcommittee delegated this responsibility to the interagency working group on ocean acidification, the group they also tasked with development of the research and monitoring plan. stored and made available to government officials, researchers, and the public. The chair of the working group told us the group has not established a single exchange but said that information on ocean acidification, including on federal agencies’ actions and research results, is available on the working group’s and other federal websites. The chair also said she recognized the value of establishing a single exchange but that doing so was a lower priority than other needed actions, such as developing the research and monitoring plan. Nonetheless, it has been more than 5 years since FOARAM was enacted, and some stakeholders we interviewed said that, without establishing a single information exchange, researchers and the public may have difficulty accessing all of the information on ocean acidification that the agencies are developing. In addition, our previous work has found that information technology, such as shared databases and web portals, can be a tool that facilitates interagency collaboration. According to NOAA officials, the National Oceanographic Data Center could serve as a building block for an ocean acidification information exchange. The interagency working group has not developed the adaptation and mitigation strategies to conserve marine organisms and ecosystems exposed to ocean acidification that are required by FOARAM. The research and monitoring plan developed by the interagency working group includes a high-level discussion of adaptation and mitigation, but it does not clearly describe adaptation and mitigation strategies. The chair of the working group said that the research and monitoring plan recognizes the importance of these topics but that more research on the effects of ocean acidification needs to be done before appropriate adaptation and mitigation strategies can be fully developed. For example, the research and monitoring plan states that future research on organisms’ responses to ocean acidification could assist with developing adaptation strategies. Research could, for instance, identify certain genetic strains in shellfish species that may be more tolerant of acidification, which could help aquaculture operations adapt to more- acidic conditions. Similarly, research on the effects of ocean acidification on species and ecosystems could assist government agencies in developing options for fishery management or assist businesses and communities in adapting to changing conditions in the future. In regard to mitigation, many officials and stakeholders we interviewed said that without timely action to mitigate its root causes, ocean acidification is likely to have significant impacts. The research and monitoring plan identified two approaches to mitigate the causes of ocean acidification: (1) reducing carbon dioxide levels in the atmosphere and (2) reducing the impact of other environmental stressors—such as nutrient runoff pollution—that can exacerbate the effects of acidification.however, did not provide a strategy for addressing these issues. Further action could be taken to advance the federal response to ocean acidification. Our previous work on interagency collaboration has found that the federal government has used a variety of mechanisms to implement collaborative efforts involving multiple agencies. These mechanisms include, among others, (1) establishing an interagency working group, (2) creating an independent interagency office with its own authority and resources, and (3) designating one or more agencies as the lead for the effort. In some cases, agencies have used more than one mechanism to implement a collaborative effort. Eleven agencies with widely varying missions are contributing to the federal response to ocean acidification. The research and monitoring plan developed by the interagency working group identified a number of goals and priorities to help guide the federal response to ocean acidification, but in many cases it is unclear which agencies will be responsible for taking action to implement them. The working group has recommended that an independent national ocean acidification program office be established to coordinate the next steps in the federal response. The National Research Council has concurred with this recommendation. Key functions envisioned for the proposed office include: facilitating coordination among federal agencies, academic researchers, and other stakeholders; developing an implementation plan that outlines the specific actions needed to achieve the goals presented in the research and monitoring plan; coordinating U.S. ocean acidification research and monitoring activities with international entities conducting similar work; establishing an ocean acidification information exchange; and developing a comprehensive ocean acidification data management plan. It is uncertain, however, when, or if, a national program office will be established. According to the former chair of the interagency working group, such an office has not been established because the working group has been unable to reach agreement on how it should be funded. Given the uncertainty about the proposed national program office, some officials we interviewed identified other options that could be pursued, such as designating NOAA as the lead agency to implement the next steps in the federal response and fulfill the functions the working group envisioned for a national program office. Regardless of the option chosen, until there is greater clarity on which entity is responsible for coordinating the next steps in the federal response to ocean acidification, completing important actions, such as implementing the research and monitoring plan, will be difficult. In response to FOARAM’s requirements, an interagency working group including 11 federal agencies has been established and has begun taking steps to better understand and respond to ocean acidification. One important action the working group has taken is the development of an ocean acidification research and monitoring plan, which outlines key efforts needed to advance the nation’s understanding of and ability to respond to acidification. However, federal efforts to implement FOARAM are incomplete. Because the research and monitoring plan does not establish each agency’s role or the budget needed for implementation, as required by FOARAM, it is unclear to what extent the actions outlined in the plan will be taken. In addition, research results and other information related to ocean acidification are available on various federal websites, but the information has not been consolidated into a single ocean acidification information exchange as required by FOARAM, which may make public access and scientific research more difficult. Finally, the research and monitoring plan lays out a broad scope of work, but an entity has not been designated to coordinate the plan’s implementation, or to identify and take whatever additional steps may be needed to help the nation address ocean acidification in the future. Without designating such an entity, federal agencies may struggle to advance the federal response to ocean acidification. To improve the federal response to ocean acidification, we recommend that the appropriate entities within the Executive Office of the President, including the Office of Science and Technology Policy and the National Science and Technology Council’s Subcommittee on Ocean Science and Technology, in consultation with the agencies in the interagency working group, take the following four actions: Clearly define the roles and responsibilities of each agency with regard to implementing the Strategic Plan for Federal Research and Monitoring of Ocean Acidification. Estimate the funding that would be needed to implement the Strategic Plan for Federal Research and Monitoring of Ocean Acidification. Establish an ocean acidification information exchange. Designate the entity responsible for coordinating the next steps in the federal response to ocean acidification. We provided a draft of this report for review and comment to the Executive Office of the President; Departments of Agriculture, Commerce, Defense, the Interior, and State; EPA; NASA; and National Science Foundation. None of the agencies commented on our recommendations or findings. NOAA, on behalf of the Department of Commerce, and the Departments of Agriculture and the Interior provided technical comments, which we incorporated, as appropriate. As agreed with your offices, unless you publicly announce the contents of this report earlier, we plan no further distribution until 30 days from the report date. At that time, we will send copies to the appropriate congressional committees; the Executive Office of the President; the Secretaries of Agriculture, Commerce, Defense, the Interior, and State; the Administrators of EPA, NASA, and NOAA; the Directors of the Bureau of Ocean Energy Management, National Science Foundation, U.S. Fish and Wildlife Service, and U.S. Geological Survey; and other interested parties. In addition, the report will be available at no charge on the GAO website at http://www.gao.gov. If you or your staff members have any questions about this report, please contact me at (202) 512-3841 or morriss@gao.gov. Contact points for our Offices of Congressional Relations and Public Affairs may be found on the last page of this report. GAO staff who made key contributions to this report are listed in appendix III. The department’s National Institute of Food and Agriculture chairs the Interagency Working Group on Aquaculture, which works to increase the overall effectiveness and productivity of federal aquaculture research and assistance programs. The working group, previously known as the Joint Subcommittee on Aquaculture, was created by statute and operates under the Office of Science and Technology Policy’s National Science and Technology Council. marine and coastal national wildlife refuges.considering establishing coral reefs located in national wildlife refuges, which are often in remote areas and experience little human disturbance, as “sentinel sites” where the service can monitor the effects of ocean acidification. In addition, it is U.S. Geological Survey. The Geological Survey has researched ocean acidification and its effects by collecting data on ocean chemistry at different locations and studying the effects of acidification on certain species. For example, one of the areas the agency has focused on is the West Florida Shelf in the Gulf of Mexico, where it has studied spatial and temporal variations in carbon chemistry and the effects of ocean acidification on the growth of calcifying organisms. The agency, in conjunction with the U.S. Coast Guard, also monitored ocean chemistry in the Arctic Ocean from 2010 through 2012, documenting that about 20 percent of the area was undersaturated with respect to aragonite, according to an agency official. U.S. Navy. The Navy has monitored research on ocean acidification conducted by others to assess any potential implications for naval operations. One implication for naval operations described in the research and monitoring plan is the potential for ocean acidification to threaten the food supply in areas of the world that are heavily dependent on marine resources for food, which, in turn, could lead to increased political instability in those regions. The Navy has also helped fund research on the effects that ocean acidification might have on how sound travels through water, because of its potential impact on sonar systems, which are important to naval operations. Any disruption to food supply that may be caused by ocean acidification will disproportionately affect countries that are dependent on fish protein as a key element of their diet. The Food and Agriculture Organization of the United Nations reported in 2012 that fish accounted for 50 percent or more of animal protein consumed in some island and developing countries, whereas it accounted for only 16.6 percent of animal protein consumed globally. The agencies that were part of the interagency working group in 2013 estimated that between fiscal years 2010 and 2013 they collectively spent approximately $88 million on activities directly related to ocean acidification (see table 1). The expenditures shown for fiscal years 2010 and 2011 are estimates provided by the working group’s component Expenditures shown for agencies to the interagency working group.fiscal years 2012 and 2013 are preliminary estimates, according to the chair of the interagency working group, and were provided to us by agency officials. For all years, estimates do not include expenditures for actions that may have benefitted the federal response to ocean acidification but that were not made with ocean acidification specifically in mind (e.g., research on the global carbon cycle that provides information useful to ocean acidification researchers but that was funded as part of an agency’s climate change portfolio). In addition to the individual named above, Stephen D. Secrist (Assistant Director), Cheryl Arvidson, Christina Cantor, Jonathan Dent, Karen Howard, Timothy M. Persons, Anne Rhodes-Kline, Jeanette Soares, Sarah Veale, and Joshua Wiener made key contributions to this report.

Summary: Increasing carbon dioxide levels in the atmosphere and oceans are resulting in chemical changes referred to as ocean acidification. These changes may pose risks for some marine species and ecosystems, as well as for the coastal communities that rely on them for food and commerce. FOARAM requires various federal entities to take specific actions related to ocean acidification. GAO was asked to review federal efforts to address ocean acidification. This report discusses (1) the scientific understanding of the effects of ocean acidification; (2) the extent to which federal agencies have implemented FOARAM; and (3) additional actions, if any, that could be taken to advance the federal response to ocean acidification. To address these issues, GAO reviewed six summary reports on ocean acidification, other scientific studies, and agency documents, and interviewed key agency officials. Ocean acidification could have a variety of potentially significant effects on marine species, ecosystems, and coastal communities, according to six summary reports that GAO reviewed. The reports were developed by federal agencies and others and were based on extensive reviews of the scientific literature. The scientific understanding of these effects, however, is still developing, and uncertainty remains about their scope and severity. Potential effects of ocean acidification include: Reducing the ability of some marine species, such as oysters, to form shells or altering their physiology or behavior. These impacts could affect some species' growth and survival. Altering marine ecosystems, for example, by disrupting predator and prey relationships in food webs and altering habitats. Disrupting the economy or culture of some communities, for example, by harming coastal fishing and tourism industries. The National Science and Technology Council's Subcommittee on Ocean Science and Technology, in the Executive Office of the President, and several federal agencies have taken steps to implement the Federal Ocean Acidification Research and Monitoring Act of 2009 (FOARAM) but have yet to complete some of the act's requirements. For example, an interagency working group, which includes representatives from 11 agencies and is chaired by the Department of Commerce's National Oceanic and Atmospheric Administration, has been established. The working group has developed a research and monitoring plan outlining steps to advance the nation's understanding of, and ability to respond to, ocean acidification. However, the agencies involved have yet to implement several FOARAM requirements, including outlining the budget requirements for implementing the research and monitoring plan. Some agency officials told GAO that not providing budget estimates has prevented the agencies and Congress from accurately understanding the funding needed to implement the plan and how it compares with current funding levels. Further action could be taken to advance the federal response to ocean acidification. GAO's previous work on interagency collaboration has found that a variety of mechanisms can be used to implement efforts involving multiple federal agencies by helping to facilitate collaboration. One possible approach, recommended by the interagency working group, is to establish an independent national ocean acidification program office to coordinate the next steps in the federal response. The working group, however, has not established such an office because it has been unable to reach agreement on how it should be funded. Until greater clarity is provided on the entity responsible for coordinating the next steps in the federal response to ocean acidification, completing important actions, such as implementing the research and monitoring plan, will be difficult. GAO recommends the appropriate entities within the Executive Office of the President take steps to improve the federal response to ocean acidification, including estimating the funding that would be needed to implement the research and monitoring plan and designating the entity responsible for coordinating the next steps in the federal response. GAO provided a draft of this report for review and comment to the Executive Office of the President and the departments and agencies reviewed. None of the agencies commented on GAO's recommendations; several provided technical comments that were incorporated, as appropriate.