The AOAT project is engaged in monitoring/modeling efforts designed to: a) establish methodologies for monitoring, assessing, and modeling the impacts of Ocean Acidification (OA) on coral reef ecosystems, b) identify critical thresholds, impacts, and trends necessary for developing forecasts, c) characterize the variability in carbonate chemistry in coral reef environments, and d) provide data and information needed to inform ecological impact forecasting. Existing projections of OA on coral reef ecosystems (e.g. Silverman et al., 2009) make a core assumption that secular declines in carbonate mineral saturation state (O, a key parameter of OA interest) are equivalent to those experienced in the oceanic surface waters. Sustained observations at the AOAT, however, reveal considerable complexity and diverge from neighboring oceanic waters during most periods. Seasonal ranges in O-values exceed those anticipated as aconsequence of OA over the next several decades. Complexities within near-reef waters are likely the norm and we seek to better model the primary controls on near-reef carbonate chemistry. The AOAT has served as a critical venue to foster research from other agency and academic partners towards the development of techniques which can be applied to monitor OA within reef environments and quantify the local feedbacks that can alter rates and magnitude.

Scientists within the ACCRETE (Acidification, Climate, and Coral Reef Ecosystems Team) Lab of AOML_s Ocean Chemistry and Ecosystems Division (OCED) have constructed a tool to monitor ocean acidification over the wider Caribbean and Gulf of Mexico. This tool utilizes satellite data and a data-assimilative hybrid model to map the components of the carbonate system of surface water. This effort represents an update to the experimental Ocean Acidification Product Suite (OAPS) developed by Coral Reef Watch (http://coralreefwatch.noaa.gov/satellite/oa/index.php). To resolve the seawater carbonic acid system, we use the partial pressure of CO2 (pCO2) and pH. Surface pCO2 is approximated by taking total tropospheric column CO2 from the AIRS mid-tropospheric CO2 and AMSU instruments on board the Aqua satellite (http://disc.sci.gsfc.nasa.gov/AIRS/data-holdings/by-data-product-v5/AIRX3C2M) and adjusting it for the marine boundary layer by replacing the annual cycle of the observed AIRS data with that from the NOAA Marine Boundary Layer (http://www.esrl.noaa.gov/gmd/ccgg/mbl/). Following this adjustment, seawater pCO2 is estimated using an empirical model relating the differential between sea surface and atmospheric CO2 partial pressure to changes in CO2 gas solubility (K0). Total alkalinity (TA) is calculated using the Subtropical/Tropical algorithm from Lee et al. (2006). Sea surface temperature is derived from an optimal interpolated product at 9km resolution (http://www.remss.com/measurements/sea-surface-temperature/oisst-description) and salinity is obtained from a data-assimilative hybrid model (HYCOM https://hycom.org/). These measurements, together with pCO2 and TA, allow calculation the complete carbonate system. Data are updated monthly at a 9km resolution. Initial results indicate good agreement with observed values from cruises and MAPCO2 buoys, but further testing and refinement of algorithms is planned.

This dataset includes lab-based measurements of ocean acidification on Caribbean bioeroders (endolithic algae and reef-excavating sponges) collected on Cheeca Rocks Reef, Florida Keys, Northwest Atlantic Ocean, from 2018-06-11 to 2018-07-12. Caribbean coral reef ecosystems have entered a state of net erosion in response to ocean acidification (OA) due to a combination of reduced carbonate production and enhanced bioerosion. The negative response of coral reef calcifiers to OA has been well-established, whereas OA-enhanced bioerosion is relatively poorly understood. Microboring algae and macroboring sponges are both major contributors to coral reef carbonate budgets (Perry et al., 2012). Microboring algae use exclusively chemical (extracellular ion transport) means (Garcia-Pichel, 2006) to break down carbonate framework, whereas macroboring sponges use a combination of both chemical (enzymatic dissolution) and mechanical (substrate dislodgment) methods (Rutzler and Rieger, 1973) to erode reef framework. Prior studies have found that both microboring algae and macroboring sponges appear to benefit from OA through both enhanced bioerosion and physiological fitness, but have disproportionally focused on the responses of Pacific Ocean species. Here, we independently evaluated the OA-response of two Caribbean bioeroders to quantify the impact of OA on their physiology and bioerosion rates.

The AOAT project is engaged in monitoring/modeling efforts designed to: a) establish methodologies for monitoring, assessing, and modeling the impacts of Ocean Acidification (OA) on coral reef ecosystems, b) identify critical thresholds, impacts, and trends necessary for developing forecasts, c) characterize the variability in carbonate chemistry in coral reef environments, and d) provide data and information needed to inform ecological impact forecasting. Existing projections of OA on coral reef ecosystems (e.g. Silverman et al., 2009) make a core assumption that secular declines in carbonate mineral saturation state (O, a key parameter of OA interest) are equivalent to those experienced in the oceanic surface waters. Sustained observations at the AOAT, however, reveal considerable complexity and diverge from neighboring oceanic waters during most periods. Seasonal ranges in O-values exceed those anticipated as aconsequence of OA over the next several decades. Complexities within near-reef waters are likely the norm and we seek to better model the primary controls on near-reef carbonate chemistry. The AOAT has served as a critical venue to foster research from other agency and academic partners towards the development of techniques which can be applied to monitor OA within reef environments and quantify the local feedbacks that can alter rates and magnitude.

Coral cores collected nearby the Atlantic Ocean Acidification Test-bed (AOAT) at La Parguera, Puerto Rico were used to characterize the relationship between paleo-variations in coral growth and calcification and seawater pH via the boron isotope proxy. This study addressed impacts of ocean acidification in a geological context to quantify baseline variability in growth and pH and assess the historical response of coral ecosystems to increased atmospheric CO2 and enhance on-going AOAT observations.

This data set was collected from a ocean acidification minicosm experiment performed at Davis Station, Antarctica during the 2014/15 summer season. It includes: - description of methods for all data collection and analyses. - environmental data logged throughout the experiment; nutrients, temperature, light climate. - carbonate chemistry data; pH (on Total scale), fugacity of CO2, dissolved inorganic carbon concentration, practical alkalinity, Omega calculations for both araganite and calcite. - product datasheet (including transmission spectra) of Osram 150W HQI-TS/NDL metal halide lamps.

This dataset includes high-frequency (hourly to sub-hourly) coastal acidification time-series data collected during nine deployments in the aforementioned seven estuaries along the US East Coast, US West Coast and Gulf of Mexico from 2015-04-23 to 2020-07-29. These data include water temperature, salinity, partial pressure of carbon dioxide (pCO2) in water, dissolved oxygen (DO) in water, and pH on the total scale. The instruments used to collected these data include Sunburst SAMI-CO2, Pro-Oceanus CO2-Pro CV and a LiCOr LI-820 CO2 gas analyzers for autonomous pCO2 measurements, Sea-Bird SeapHOx and SeaFET instruments for pH measurements, Sea-Bird SeapHOx and Aanderaa Oxygen Optode instruments for DO measurements, and YSI water sensing instrument packages for measurements of conductivity (salinity), temperature and depth. Beginning in 2015, the U.S. Environmental Protection Agency’s (EPA) National Estuary Program (NEP) started a collaboration with partners in seven estuaries along the East Coast (Barnegat Bay; Casco Bay), West Coast (Santa Monica Bay; San Francisco Bay; Tillamook Bay), and the Gulf of Mexico (GOM) Coast (Tampa Bay; Mission-Aransas Estuary) of the United States to expand the use of autonomous monitoring partial pressure of carbon dioxide (pCO2) and pH sensors to evaluate carbonate chemistry in the estuarine environment.

The NOAA Atlantic Oceanographic and Meteorological Laboratory (AOML) through a collaboration with the National Park Service collected ocean acidification discreet samples at select National Parks sites along the East Coast of the United States and in the Gulf of Mexico to increase near-shore data collection on a bi-annual frequency. Whenever possible, sample collection is coordinated with the OAP-funded GOMECC and ECOA cruises.

This data package contains a hybrid surface OA data product that is produced based on three recent observational data products: (a) the Surface Ocean CO2 Atlas (SOCAT, version 2022), (b) the Global Ocean Data Analysis Product version 2 (GLODAPv2, version 2022), and (c) the Coastal Ocean Data Analysis Product in North America (CODAP-NA, version 2021), and 14 Earth System Models from the sixth phase of the Coupled Model Intercomparison Project (CMIP6). The trajectories of ten OA indicators, including fugacity of carbon dioxide, pH on Total Scale, total hydrogen ion content, free hydrogen ion content, carbonate ion content, aragonite saturation state, calcite saturation state, Revelle Factor, total dissolved inorganic carbon content, and total alkalinity content are provided under preindustrial conditions, historical conditions, and future Shared Socioeconomic Pathways: SSP1-19, SSP1-26, SSP2-45, SSP3-70, and SSP5-85 from 1750 to 2100 on a global surface ocean grid. These OA trajectories are improved relative to previous OA data products with respect to data quantity, spatial and temporal coverage, diversity of the underlying data and model simulations, and the provided SSPs over the 21st century.