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.
Evaluation of OA impacts to plankton and fish distributions in the Gulf of Mexico during GOMECC-4 with a focus on HAB-interactions
Why we care
Ocean change in the Gulf of Mexico, including acidification and eutrophication, can impact biodiversity and the flow of energy through ecosystems from microscopic phytoplankton to higher trophic levels like fish. These processes can impact the health of fisheries and coastal ecosystems. This project collects information to evaluate the links between ocean conditions and important species in the Gulf of Mexico.
What we are doing
During the 4th Gulf of Mexico Ecosystem and Carbon Cruise (GOMECC-4), scientists collect samples of phytoplankton, zooplankton, and ichthyoplankton to characterize fish distribution and abundance, larval fish condition and diet, microplastic abundance, and harmful algal bloom species. These collections coincide with measurements of acidification, oxygen, and eutrophication to make connections between ocean chemistry and biology.
Benefits of our work
This project will help characterize how changes in ocean conditions interact with biological processes like harmful algal bloom formation and ecosystem productivity that are important to local fisheries and stakeholders.
Assessing ecosystem responses of Gulf of Mexico coastal communities to ocean acidification using environmental DNA
Why we care
Recent efforts to monitor ocean acidification in the Gulf of Mexico via the Gulf of Mexico Ecosystems and Carbon Cycle (GOMECC) cruises have revealed spatial differences in ocean acidification. While we know that ocean acidification negatively impacts many species and exacerbates the effects of oxygen limitation and harmful algal blooms, there is little work to monitor or predict the effects of ocean acidification on biodiversity. This project employs cutting-edge technology using environmental DNA to assess biodiversity in different conditions in the Gulf of Mexico region.
What we are doing
Every organism sheds DNA. This project analyzes environmental DNA (eDNA), which is free-floating or microscopic DNA found in seawater, collected during the 4th GOMECC cruise, to identify biodiversity of bacteria, plankton, and fish in the Gulf of Mexico. eDNA will be compared to ocean properties to draw conclusions about drivers of biodiversity.
Benefits of our work
Links between eDNA, ocean acidification, and other ocean properties will provide a deeper understanding of environmental drivers of biodiversity. These relationships can inform predictions of biodiversity patterns and guide the management of key habitats in the Gulf of Mexico, and help us adapt to changing ocean conditions.
Among the NOAA designated Large Marine Ecosystems, the Gulf
of Mexico (GOM) remains poorly understood in terms of its current OA conditions, despite its
ecological and economic significance. In the northwestern GOM (nwGOM), decadal
acidification has been observed in the shelf-slope region, with metabolic production of CO2
contributing to a larger fraction of CO2 accumulation than uptake of anthropogenic CO2, and the
observed rate of acidification is significantly greater than that in other tropical and subtropical
areas. Unfortunately, whether the observed OA in this region represents a short-term
phenomenon or a long-term trend is unknown.
It is hypothesized that increasing atmospheric CO2, increasing terrestrial nutrient export
due to an enhanced hydrological cycle, and enhanced upwelling due to climate change will cause
the continental shelf-slope region in the nwGOM to acidify faster than other tropical and
subtropical seas. In order to test this hypothesis wave gliders, in -stiu sensor along withe underway measurements from research vessels will measure carbonated chemistry in in surface and shallow waters. Modeling will be used tp integrate the chemical signals into the models to hindcast/predict spatia; and temporal variation of the OA signal for the the optimization of monitoring design and implementation.
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.
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.