Understanding the exposure of the nation’s living marine resources such as shellfish and corals to changing ocean chemistry is a primary goal for the NOAA OAP. Repeat hydrographic surveys, ship-based surface observations, and time series stations (mooring and ship-based) in the Atlantic, Pacific, and Indian Oceans have allowed us to begin to understand the long-term changes in carbonate chemistry in response to ocean acidification.
When the ocean absorbs carbon dioxide, chemical reactions create hydrogen ions that act like free agents, able to react with other compounds. Two ways we track ocean acidification are through pH and total alkalinity (TA). pH is a measure of how many free hydrogen ions are in the seawater. The more carbon dioxide in the ocean, the more these free agents are created, causing lower pH (more acidic).
The partial pressure of CO2 (pCO2) tells us how much carbon dioxide is in seawater. This information helps us understand ocean carbonate chemistry and biological productivity in the region. pCO2 increases when the ocean absorbs more CO2 from the atmosphere with elevated emissions.
Alkalinity is the ocean’s buffering system against increasing acidity. Total alkalinity is a measure of the concentration of buffering molecules like carbonate and bicarbonate in the seawater that can neutralize acid.
Dissolved inorganic carbon (DIC) tells us how much non-biological carbon is in seawater. Inorganic carbon comes in three main forms that we measure for DIC: carbon dioxide (CO2), bicarbonate (HCO3-), and carbonate (CO32-). Understanding DIC can help us determine the balance of carbonate forms in the ocean and the likelihood of ocean acidification.
There are currently 19 OAP-supported buoys in coastal, open-ocean and coral reef waters which contribute to NOAA's Ocean Acidification Monitoring Program, with other deployments planned.
Currently, there are two types of floating devices which instruments can be added in order to measure various ocean characteristics - buoys and wave gliders. Buoys are moored, allowing them to remain stationary and for scientists to get measurements from the same place over time. The time series created from these measurements are key to understanding how ocean chemistry is changing over time. There are also buoys moored in the open-ocean and near coral reef ecosystems to monitor the changes in the carbonate chemistry in these ecosystems. The MAP CO2 sensors on these buoys measure pCO2 every three hours.
Access our buoy data
Research cruises are a way to collect information about a certain ecosystem or area of interest.
For decades, scientists have learned about physical, chemical and biological properties of the ocean and coasts by observations made at sea. Measurements taken during research cruises can be used to validate data taken by autonomous instruments. One instrument often used on research cruises is a conductivity, temperature, and depth sensor (CTD), which measures the physical state of the water (temperature, salinity, and depth). The sensor often goes in the water on a rosette, which also carries niskin bottles used to collect water samples from various depths in the water column. Numerous chemical and biological properties can be measured from water collected in niskin bottles.
Ships of Opportunity (SOPs) or Volunteer Observing Ships (VOSs) are vessels at sea for other reasons than ocean acidification studies, such as commercial cargo ships or ferries.
The owners of these vessels allow scientific instrumentation that measures ocean acidification (OA) parameters to be installed and collect data while the ship is underway. This allows data on ocean chemistry to be collected in many remote areas of the world's ocean, such as high latitude waters, long distances from land (e.g. mid-basin waters), and places not easily accessible by research cruises. These partnerships have greatly increased the spatial coverage of OA monitoring world-wide. To learn more, check out the Ships of Opportunity programs established by the NOAA Pacific Marine Environmental Laboratory (PMEL) and the NOAA Atlantic Oceanographic Marine Laboratory (AOML).
Scientists at the NOAA Pacific Marine Environmental Laboratory (PMEL) are working with engineers at Liquid Robotics, Inc. to optimize a Carbon Wave Glider.
This instrument (pictured above) can be driven via satellite from land. Carbon Wave Gliders can be outfitted with pCO2, pH, oxygen, temperature and salinity sensors, and the glider’s equipment takes measurements as it moves through the water. The glider’s motion is driven by wave energy, and its sensors are powered through solar cells and batteries, when needed.
NOAA’s Coral Reef Conservation Program (CRCP) in partnership with OAP is engaged in a coordinated and targeted series of field observations, moorings and ecological monitoring efforts in coral reef ecosystems.
These efforts are designed to document the dynamics of ocean acidification (OA) in coral reef systems and track the status and trends in ecosystem response. This effort serves as a subset of a broader CRCP initiative referred to as the National Coral Reef Monitoring Plan, which was established to support conservation of the Nation’s coral reef ecosystems. The OAP contributes to this plan through overseeing and coordinating carbonate chemistry monitoring. This monitoring includes a broadly distributed spatial water sampling campaign complemented by a more limited set of moored instruments deployed at a small subset of representative sites in both the Atlantic/Caribbean and Pacific regions. Coral reef carbonate chemistry monitoring is implemented by researchers at the NOAA Atlantic Oceanographic & Meteorological Laboratory (AOML) and NOAA's PIFSC Coral Reef Ecosystems Division.
Ocean Acidification on a Crossroad: Enhanced Respiration, Upwelling, Increasing Atmospheric CO2, and their interactions in the northwestern Gulf of Mexico
Why we care
In the coastal ocean, local drivers such as nutrient input and physical oceanographic changes impact the magnitude of short-term variations and long-term trends in ocean acidification. The Gulf of Mexico’s coral reefs and banks are ecologically sensitive to changing ocean chemistry. Decadal acidification has been observed in the Northwestern Gulf of Mexico, linked more strongly to biological production of carbon dioxide than uptake of human-emitted carbon dioxide. Whether the observed acidification in this region represents a short-term phenomenon or a long-term trend is unknown. This project maintains critical ocean acidification monitoring in a region with impacted habitats and species.
What we are doing
This project will test the hypothesis that enhanced atmospheric carbon dioxide, nutrient input, and upwelling will cause the continental shelf-slope region in the Northwestern Gulf of Mexico to acidify faster than other tropical and subtropical seas. The research team will incorporate observations from new large-scale surveys into oceanographic and statistical models that predict variation in ocean acidification over space and time.
Benefits of our work
The outcomes of this project will meet the long-term goal of optimizing ocean acidification monitoring in the Northwestern Gulf of Mexico and will document methodology that can be used in similar efforts in the future. This project will examine an area in the poorly understood Gulf of Mexico Large Marine Ecosystem, produce the first ever high-resolution dataset in surface and subsurface waters, and direct the future deployment of in-situ monitoring devices in this ecologically and economically important region.
Whether you arrive on the Olympic Peninsula by land, sea, or air, you sense its remote, rugged and vast environment immediately. The Olympic Coast is home to productive waters which sustain thriving marine and coastal communities that have long supported the region’s tribal peoples. Ocean waters quickly deepen just offshore, boasting canyons which extend almost a mile below the surface – and have yet to be fully explored.
The University of South Carolina (Columbia, South Carolina, USA) and the Belle W. Baruch Institute for Marine and Coastal Sciences is seeking a postdoctoral fellow, funded by the Nippon Foundation-Nereus Program, to join our interdisciplinary team of researchers to explore the responses of forage fish populations in eastern boundary upwelling ecosystems to physical and biogeochemical variability associated with future climate change. The goal of the project is estimation of fisheries productivity given projected changes in upwelling intensity and seasonality, nutrient stoichiometry, acidification, and plankton production and composition.