Biological Response

NOAA's Ocean Acidification Program supports research that focuses on economically and ecologically important marine species. Research of survival, growth, and physiology of marine organisms can be used to explore how aquaculture, wild fisheries, and food webs may change as ocean chemistry changes.


A number of NOAA National Marine Fisheries Service Science Centers have state-of-the-art experimental facilities to study the response of marine organisms to the chemistry conditions expected with ocean acidification.

The Northeast Fisheries Science Center has facilities at its Sandy Hook, NJ and Milford, CT laboratories; the Alaska Fisheries Science Centers at its Newport, OR and Kodiak, AK laboratories; and the Northwest Fisheries Science Center at its Mukilteo and Manchester, WA laboratories. All facilities can tightly control carbon dioxide and temperature. The Northwest Fisheries Science Center can also control oxygen, and can create variable treatment conditions for carbon dioxide, temperature, and oxygen. These facilities include equipment for seawater carbon chemistry analysis, and all use standard operating procedures for analyzing carbonate chemistry to identify the treatment conditions used in experiments.



Both deep sea and shallow reef-building corals have calcium carbonate skeletons.  As our oceans become more acidic, carbonate ions, which are an important part of calcium carbonate structures, such as these coral skeletons, become relatively less abundant. Decreases in seawater carbonate ion concentration can make building and maintaining calcium carbonate structures difficult for calcifying marine organisms such as coral.



Increased levels of carbon dioxide in our ocean can have a wide variety of impacts on fish, including altering behavior, otolith (a fish's ear bone) formation, and young fish's growth. Find out more about what scientists are learning about ocean acidification impacts on fish like rockfish, scup, summer flounder, and walleye pollock.


Shellfish, such as oyster, clams, crabs and scallop, provide food for marine life and for people, too. Shellfish make their shells or carapaces from calcium carbonate, which contains carbonate ion as a building block. The decreases in seawater carbonate ion concentration expected with ocean acidification can make building and maintaining calcium carbonate structures difficult for calcifying marine organisms like shellfish. This may impact their survival, growth, and physiology, and, thus, the food webs and economies that depend on them.


Plankton are tiny plants and animals that many marine organisms, ranging from salmon to whales, rely on for nutrition. Some plankton have calcium carbonate structures, which are built from carbonate ions. Carbonate ions become relatively less abundant as the oceans become more acidic. Decreases in seawater carbonate ions can make building and maintaining shells and other calcium carbonate structures difficult for calcifying marine organisms such as plankton. Changes to the survival, growth, and physiology of plankton can have impacts throughout the food web.


A Strategy for Ocean and Coastal Acidification (OCA) Education and Citizen Science Monitoring in the Northeast

Beth Turner

This project will cross-calibrate citizen science monitoring protocols for ocean acidification among independent organizations in the Northeast by developing a replicable citizen science monitoring training program. This will be accomplished by providing trainings and materials specific for volunteer and citizen science audiences through a series of regional workshops. The project team will (1) develop the first replicable citizen science monitoring program in accordance with recently developed EPA guidance document, Guidelines for Measuring Changes in Seawater pH and Associated Carbonate Chemistry in Coastal Environments of the Eastern United States, (2) provide in-person technical trainings and educational materials through an initial series of three regional workshops in Maine, Massachusetts and Connecticut and (3) support the successful use of citizen science participation in research and management by building on the Northeast Coastal Acidification Network’s extensive capacity and stakeholder network.

Friday, April 28, 2017
Categories: Projects

Tracking Ocean Alkalinity using New Carbon Measurement Technologies (TAACT)

Joe Salisbury

This project will expand the quantity and quality of ocean acidification (OA) monitoring across Northeastern U.S. coastal waters. The new OA data and incorporation of the world’s first commercial total alkalinity (TA) sensor into our regional observing system (NERACOOS) are designed to supply needed baseline information in support of a healthy and sustainable shellfish industry, and to aid in assessments and projections for wild fisheries. In working with partners to develop this proposal, clear concerns were brought forward regarding the potential impacts of increasing ocean acidity that extend from nearshore hatcheries and aquaculture to broader Gulf of Maine finfish and shellfish industries and their management. Stakeholder input and needs shaped the project scope such that both nearshore and offshore users will be served by TA sensor deployments on partner platforms, including time series data collection at an oyster aquaculture site, on the NOAA Ship of Opportunity AX-2 line, and on federal and State of Maine regional fish trawl surveys. In all, five different deployment platforms will be used to enhance ocean acidification monitoring within the Northeast Coastal Acidification Network (NE-CAN) with significant improvement in temporal and spatial coverage.

 Adding the all-new TA measurement capability to the regional observation network will provide more accurate, certain, and reliable OA monitoring, and an important project objective is to demonstrate and relay this information to regional partners. Data products to be developed from the multi-year measurements include nearshore and offshore baseline OA seasonal time series as well as threshold indices tied to acidification impacts on larval production at the Mook Sea Farm oyster hatchery. An outreach and technical supervision component will include the transfer of carbonate system observing technologies to our partners and to the broader fishing industry, resource management, and science communities. NERACOOS will provide data management and communication (DMAC) services and work towards implementing these technological advances into the IOOS network.

Wednesday, January 25, 2017
Categories: Projects

Interactions between ocean acidification and eutrophication in estuaries: Modeling opportunities and limitations for shellfish restoration

Jeremy Testa, University of Maryland Center for Environmental Science (UMCES) Chesapeake Biological Laboratory

The objective of this project is to make significant strides in bridging the gap between scientific knowledge and current management needs by integrating existing biogeochemical model frameworks, field measurements, and experimental work toward the goals of (1) delineating atmospheric and eutrophication drivers of Chesapeake Bay acidification and improve our understanding of estuarine carbonate chemistry, (2) developing a spatially explicit framework to identify shellfish restoration areas most and least prone to acidification impacts, and (3) better understanding feedbacks associated with future environmental conditions and shellfish restoration goals estuary-wide and within a model tributary. This effort includes (1) a field campaign to make the first comprehensive study of the spatial and temporal variability in the carbonate system in Chesapeake Bay, (2) experiments to quantify both carbonate and nutrient exchange between intact oyster reefs and the surrounding water while measuring response of these fluxes to reef structure and acidification, and (3) an advancement in numerical modeling tools to simultaneously simulate the dynamics of eutrophication, hypoxia, carbonate chemistry, and oyster reef growth and interaction with the water-column under present and future conditions.

Wednesday, January 25, 2017
Categories: Projects

Flexing mussels: Does Mytilus edulis have the capacity to overcome effects of Ocean Acidification?

Dianna K Padilla, Stony Brook University

We are likely to see "winners", those species or individuals that are most resilient in the face of climate change, and "losers" those species or individuals that are least capable of robust performance under stressful conditions.  At present, we cannot predict winners and losers, and do not know whether responses to environmental stress are primarily driven by phenotypic plasticity, broad performance under different environmental conditions, or if there are genetic or epigenetic factors that can result in cross-generational directional changes in populations, resulting in more resilience under stressful conditions of OA.   This project has two objectives: 

1)  To test for cross-generational adaptation to the impacts of increasing ocean acidification on blue mussels, either through phenotypic acclimation or through heritable changes. 

2)  To determine if there are tradeoffs in growth and development across life stages in response to stress induced by ocean acidification in blue mussels.\

The results of our experiments can then be used to develop management practices for wild populations and more robust aquaculture practices for blue mussels. From an aquaculture perspective, if animals from certain source populations are more resilient to OA stress, those locations could be targeted for collection of wild seed that will produce resilient mussels in aquaculture leases.  Furthermore, the environmental characteristics of these advantageous site(s) could then be characterized to predict other sites that may also produce resilient mussels.  Overall, the data obtained from this proposed work could be used to enhance mussel culture, an economically important activity of growing importance in our region.

Wednesday, January 25, 2017
Categories: Projects

Sensitivity of larval and juvenile sand lance Ammodytes dubius on Stellwagen Bank to predicted ocean warming, acidification, and deoxygenation

Hannes Baumann, University of Connecticut

This proposal will quantify the sensitivity of a key forage fish in the Northwest Atlantic to the individual and combined effects of the major factors comprising the ocean climate change syndrome: warming, acidification, and deoxygenation. We will rear embryos of Northern sand lance Ammodytes dubius, obtained by strip-spawning wild adults from the Stellwagen Bank National Marine Sanctuary (SBNMS) through larval and early juvenile stages in a purpose- built factorial system at different factorial combinations of temperature, CO2 and oxygen.

Our first objective is to quantify individual and combined effects of temperature × CO2 (year 1) and temperature × CO2 × DO (year 2) on A. dubius growth and survival. We hypothesize that warming in combination with high CO2 (low pH)  will have additive or synergistically negative effects, whereas the addition of low DO as a third stressor will have stark, synergistically negative effects on all traits. Our second objective is to characterize the swimming behavior of A. dubius larvae that have been reared under combinations of elevated temperature × CO2. We hypothesize that combined stressors will have synergistically negative effects on the development of larval sensory systems, which express themselves and can thus be quantified as changes in larval swimming behavior. Our third objective is to take advantage of the rare winter sampling activities for this project to quantify CO2, pH, and DO variability in benthic waters on Stellwagen Bank through bottle collections and short-term sensor deployments. We hypothesize that bottom water pH and DO levels during the sand lance spawning season might be routinely lower than levels in surface waters.

Wednesday, January 25, 2017
Categories: Projects