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.
Accelerating Ocean Acidification Sensor Development
Why we care After nearly a decade, the NOAA Ocean Acidification Observing Network (NOA-ON) has reached the maturity level where a sustained effort to refresh its core technology, the Moored Autonomous pCO2 (MAPCO2), is necessary to maintain the current monitoring level. There is also the pressing need to develop technology to both improve the accuracy and reliability of the measurement of a second carbonate system parameter (dissolved inorganic carbon, DIC) in order to better measure and understand ocean acidification (OA).
What we are doing We will develop a modestly-priced, mass-producible, climate-quality surface ocean system that will measure 2 key parameters (pCO2, DIC) of the oceans carbonate (buffering) system. The system will be deployable on a variety of autonomous platforms and vehicles to meet the needs of both the ocean acidification and surface ocean carbon dioxide international observing networks.
Benefits of our work The NOA-ON network can sustain these important observations while adding the ability to autonomously observe the ocean with a measurement quality sufficient to detect long-term changes in ocean acidification. This is a priority task for NOA-ON, the Global Ocean Acidification Observing Network (GOA-ON) and others that cannot be accomplished with current technology. The pCO2-DIC sensor developed under this project will contribute towards better assessment of the vulnerability of U.S. waters to ocean acidification by providing access to real time information about the variability of OA, meeting the needs of several stakeholders in the marine resource community.
Assessing ocean acidification as a driver for enhanced metals uptake by Blue mussels (Mytilus edulis): implications for aquaculture and seafood safety
Why we care Ocean acidification causes changes in the chemistry of stressors such as metals and may affect both the susceptibility of these animals to the contaminants as well as the toxicity. This is especially important for animals like blue mussels and other economically important shellfish that accumulate toxins in their bodies. Metal accumulation as a co-stressor of ocean acidification is not well documented for northeastern U.S. shellfish aquaculture species and better understanding these relationships supports seafood safety.
What we are doing This work investigates the impacts of metal speciation (forms) on blue mussels under acidified conditions in both field and laboratory experiments. Scientists will first study uptake rates of these metals by blue mussels and then see how changing conditions affects their accumulation and toxicity. Comparing what they learn in the lab to what occurs in the field where these mussels are farmed, helps support decisions for seafood safety and industry best practices.
Benefits of our work Coastal managers and aquaculturists can use these results that provide the societal benefits of better informed siting of aquaculture and safer seafood.
PMEL Sustained Ocean Acidification Biogeochemical and Ecological Survey Observations
Why we care U.S. West coast-wide hydrographic surveys have been conducted intermittently from 2007 to 2017, providing evidence for the geographic extent and severity of ocean acidification in the continental shelf ecosystem. Scientists on the NOAA West Coast Ocean Acidification (WCOA) discovered that the combined effects of anthropogenic and biologically-derived carbon dioxide resulted in significant biological impacts for oyster larvae and pteropods, which are small, ecologically important mollusks for the food web.
What we are doing This project executes a large-scale survey of ocean acidification carbonate chemistry in the California Current System and continues processing data and publishing scientific papers based on 2016 and 2017 surveys findings. This survey determines the spatial distributions of temperature, salinity, pH, dissolved inorganic carbon, total alkalinity, oxygen, nutrients, and biological parameters along the west coast of North America. Survey results will provide the basis for accurate assessments of changing ocean chemistry in the following areas: 1) spatial variability; 2) extent and causes of long-term changes in carbonate system parameters and their impacts on calcifying (shell-building) organisms; and 3) empirical relationships for obtaining high-resolution information on ocean acidification collected on moorings.
Benefits of our work This project links the combined stressors of increased temperature, acidification, and hypoxia (low oxygen) with effects on marine organisms in the region and identifies spatial variability of acidifying conditions during the spring/summer upwelling season. In addition to scientific partners, this project engages a NOAA Teacher At Sea (TAS) fellow on the cruise to help develop outreach and education on West Coast ocean acidification.
PMEL Sustained Investment Coastal Underway Ocean Acidification Observations (PUO)
Why we care Underway ship measurements of ocean acidification (OA) data on ships of opportunity (SOOP) have proven to be a robust and cost-effective way of expanding OA observations. Ship-based observations provide an understanding of the spatial extent of processes that drive OA. Surface underway observations, in conjunction with coastal moorings and dedicated large-scale surveys, make an important contribution to addressing the hypothesis that acidification varies across space and time as a consequence of local and regional processes.
What we are doing The focus of this project is to sustain existing underway OA monitoring systems on NOAA Ships Oscar Dyson and Bell M. Shimada, which operate along the U.S. West Coast. Project objectives also include sustaining underway OA observations in the equatorial Pacific, upgrading sensor systems, and improving oxygen data collection.
Benefits of our work This project increases high-quality surface water OA data taken underway to accompany NOAA Fisheries cruises. Efforts also improve spatial and temporal coverage of OA measurements, improving our understanding of OA variability along the Pacific coast of North America.