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.


Building Robust Reef Carbonate Projections from Synthesized NCRMP Ocean Acidification Datasets

Tom Oliver and Derek Manzello, NOAA Coral Reef Conservation Program

This project will serve to (1) synthesize National Coral Reef Monitoring Program (NCRMP) OA Enterprise observations; (2) compare reef OA observations to oceanic end members to infer reefscale biogeochemical processes, and finally (3) use these synthesis products to better link projection models of oceanic carbonate systems to reef-scale OA impacts. The NCRMP OA enterprise supports: our collection of seawater samples from reef and surface observations; a set of MapCO2 buoys in the Caribbean and Hawaii; diurnal monitoring instruments (e.g. CREP's diurnal suite, AOML's/McGillis' BEAMS); and metrics of ecosystem response to OA (e.g. CAUs, coral coring, etc.). The datasets generated by these activities will be the focus of this wide-ranging synthesis.

Wednesday, November 16, 2016
Categories: Projects

Effects of elevated pCO2 and temperature on reef biodiversity and ecosystem functioning using Autonomous Reef Monitoring Structures and hyperspectral technology

Molly Timmers, NOAA Coral Reef Conservation Program

The goal of this project is to improve our understanding of the effects of ocean acidification and warming on coral reef communities by examining responses of entire suites of reef organisms recruiting to Autonomous Reef Monitoring Structures (ARMS) in benthic mesocosms. We will perform a fully factorial experiment that consists of four treatments of low and high temperature and pCO₂ levels. ARMS are the leading long-term monitoring tool to measure biodiversity on reef systems and are integrated into the National Coral Reef Monitoring Program (NCRMP) Class II and Class III climate stations dedicated to monitor and access the physical, chemical and biological impacts associated with climate change over time. We propose to examine the effects of elevated temperature and pCO₂ on recruitment, biomass, biodiversity, and community structure over a multiannual time frame to increase our understanding of how biodiversity, ecosystem function, and their relationship will be impacted under future climate scenarios. 

Wednesday, November 16, 2016
Categories: Projects

Physiological response of the red tree coral (Primnoa pacifica) to low pH scenarios in the laboratory

Bob Stone, NOAA Alaska Fisheries Science Center

Deep-sea corals are widespread throughout Alaska, including the continental shelf and upper slope of the Gulf of Alaska, the Aleutian Islands, the eastern Bering Sea, and extending as far north as the Beaufort Sea. Decreases in oceanic pH and resulting decreases in calcium carbonate saturation state could have profound effects on corals dependent on the extraction of calcium carbonate from seawater for skeletal building. Corals will be affected differently depending on their skeletal composition (aragonite vs. calcite), geographical location, and depth. The aragonite and calcite saturation horizons are already quite shallow in areas of the North Pacific Ocean and are predicted to become shallower in the near future. The skeletal composition is known for only a few Alaskan coral species and may be composed of aragonite, calcite, high-magnesium calcite, or amorphous carbonate hydroxylapatite. Skeletons composed of high magnesium-calcite are the most soluble and consequently corals with high-magnesium calcite skeletons, particularly those residing at depths deeper than the saturation horizon, are most at risk to decreases in oceanic pH. At the completion of this project we will be able to provide a comprehensive risk assessment for all corals in Alaskan waters.

Wednesday, November 16, 2016
Categories: Projects

Effects of OA on Alaskan gadids: sensitivity to variation in prey quality and behavioural response

Tom Hurst, NOAA Alaska Fisheries Science Center

To date many studies of the effects of ocean acidification on fishes have suggested that fish are somewhat resilient to effects on factors such as growth and survival. However, these experiments have generally not included potential interactive stressors which may increase the sensitivity to acidification stress. Further, experiments on some species have demonstrated the OA stress has significant potential to disrupt sensory and behavioral systems in fishes which could compromise survival in natural settings. In this project we will focus on examining the potential for behavioral disruptions due to OA and the interactive stresses of OA and nutritional state on critical Alaskan groundfishes.

Wednesday, November 16, 2016
Categories: Projects

Forecasting the effects of OA on Alaska crabs and pollock abundance

Mike Dalton, NOAA Alaska Fisheries Science Center

The aim of this project was to forecast effects of ocean acidification on the commercially important Alaska crab stocks including the Bristol Bay red king crab (BBRKC) fishery, which is part of a modern fisheries management program, the Bering Sea and Aleutian Islands (BSAI) crab rationalization program. To investigate the biological and economic impacts of OA, a linked bioeconomic model was developed that a) integrates predictions regarding trends over time in ocean pH, b) separates life-history stages for growth and mortality of juveniles and adults, and c) includes fishery impacts by analyzing catch and effort in both biological and economic terms. By coupling a pre-recruitment component with post-recruitment dynamics, the BBRKC bioeconomic model incorporates effects of OA on vulnerable juvenile crabs in combination with effects of fishing on the BBRKC population as a whole. Many types of projections under management strategies can be made using linked bioeconomic models.

Wednesday, November 16, 2016
Categories: Projects