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.


NOAA and Partners Launch Research Cruise of East Coast to Study Ocean Acidification

By: NOAA Ocean Acidification Program

Author: Anonym/Monday, June 22, 2015/Categories: ocean acidification, OA monitoring

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NOAA and partners launch research cruise of East Coast to study ocean acidification

NOAA and scientists from Princeton, Old Dominion University, and the Universities of New Hampshire, Delaware, and Miami set off on June 19th from Newport, Rhode Island aboard NOAA ship Gordon Gunter on a research cruise to better understand ocean acidification and its drivers along the U.S. East Coast. 

The R/V Gordon Gunter stationed in Newport, RI will be surveying carbonate chemistry on a 34 day research cruise,which began in the Canadian Maritime waters and will end along the Florida coast. Principal investigators of the expedition are Dr. Joe Salisbury from University of New Hampshire and Dr. Janet Reimer from University of Delaware Photo credit: Marc Emond, University of New Hampshire.  

This research cruise is just one part of a larger effort supported by the NOAA Ocean Acidification Program to better understand how ocean chemistry along all the U.S. coasts is changing in response to ocean acidification and where marine organisms may be at greatest risk. Similar cruises have taken place on the U.S. West Coast and the Gulf of Mexico. Understanding why and how fast our ocean chemistry is changing in different areas will allow scientists to better predict future changes and explore ways to adapt to those shifts.

The Gunter will travel north to survey the waters of the Nova Scotia Shelf and will then steam south, surveying waters close to shore to provide more detailed information about water chemistry within the Gulf of Maine, Long Island Sound, the Mid-Atlantic and Southern Bight regions than previous surveys. The ship will also investigate central Florida waters before reaching Miami on July 24.”

“We will be covering a larger area of the East Coast and going much closer to shore than ever before so that we can better understand the many factors contributing to ocean acidification,” said Dwight Gledhill, Deputy Director of the NOAA Ocean Acidification Program.  

This is the first time that scientists will get an in depth view of the waters in the Gulf of Maine. 

“Understanding the chemistry of water on the Scotian Shelf is critical for us to understand how ocean acidification might unfold in Maine,” Gledhill says, “The Labrador Current, which flows over the shelf and into this region is freshening due to climate change and increased Arctic ice melt. These fresher waters are more corrosive, so understanding how that will affect Maine waters is an important part of this survey.”” 

By collecting and analyzing water samples in near shore and deeper waters, scientists will better understand what drives the process of ocean acidification in different areas of the East Coast shelf. Another area new to the survey is Long Island Sound, an urbanized estuary, which is known to become acidic with low oxygen or hypoxia events. This is the first time that both carbon dioxide and oxygen, along with nutrient levels will be measured in these waters. These measurements may give insight into how nutrient run off from land based activities will impact seawater chemistry in this area. 

The CTD/rosette is an instrument that is deployed into the water to measure conductivity, temperature and density.  This rosette has a mascot for good luck at sea; "Betty" the praying mantis. Photo credit: Marc Emond, University of New Hampshire.

The ship and its crew will hug the coast as they proceed South and will be coordinating with the Environmental Protection Agency (EPA) to take measurements in very near shore waters that are too shallow for the Gunter to reach. In both Narragansett and Delaware Bays, scientists from the EPA will continue with measurements landward of the Gunter’s coastal station in coastal waters. This Mid- Atlantic Shelf region is important for sea scallop production, a significant resource and important fishery and component of the economy in this region.  

The ship will come to port in Norfolk, Va., on July 4 before continuing south. Throughout the entire survey, scientists on board will also look at how single-celled marine plants, or phytoplankton, affect ocean chemistry. Tracking ocean acidification which is caused in large part by an increase in atmospheric carbon dioxide from the burning of fossil fuels, demands careful determination of not only the marine carbonate system, but also a suite of measures that give insight into the key organisms which can modify the chemistry. Both photosynthesis and respiration of these small marine plants and other tiny organisms can alter carbon dioxide levels in the water.

Scientists will measure both carbon and oxygen in the water to better understand how they affect the growth of phytoplankton that are at the base of the food chain. Phytoplankton are not only important to the marine food chain, but these marine plants also control carbon chemistry. Scientists from the National Aeronautic and Space Administration (NASA) are working to use satellite capabilities to “see” the kind phytoplankton in the ocean by identifying the color of the ocean. Researchers on board the Gunter will sample phytoplankton in the water as a NASA satellite measures the ocean’s color in the same location.

“There are only a few things you can measure from space such as temperature, salinity and ocean color,” says Gledhill. “If we can confirm what phytoplankton are in the water at the same time the satellite is over head, while also measuring carbon chemistry this could allow scientists to relate changes in carbon chemistry to the types of phytoplankton in the water sometime in the future.”

This cruise will cover new areas and get more in depth information along the U.S. East Coast to understand the factors that influence ocean and coastal acidification. Because the East Coast has a broad shallow shelf, potentially corrosive, freshwater discharge out of rivers into the coastal ocean could be a major contributor to changing ocean chemistry. This survey will allow scientists to understand how fresher waters, coastal influences, and phytoplankton may alter our ocean chemistry. This environmental information on ocean acidification is essential to predicting its effects on important marine resources, so that communities can mitigate and adapt to these changes.


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