We evaluated the influence of diurnal carbonate chemistry variability on the bioerosion rates of two Caribbean sponges: the zooxanthellate Cliona varians and azooxanthellate Cliothosa delitrix. Sponge samples were exposed to four precisely-controlled pH treatments: contemporary static (8.05 ± 0.00; mean pH ± diurnal pH oscillation), contemporary variable (8.05 ± 0.10), future OA static (7.80 ± 0.00), and future OA variable (7.80 ± 0.10). Tank pH conditions measured throughout the entirety of the experiment are provided in the "fullExperiment_pHData.xlsx" file. Significantly enhanced bioerosion rates, determined using buoyant weight measurements, were observed under more variable conditions in both the contemporary and OA scenarios for C. varians, whereas the same effect was only apparent under contemporary pH conditions for C. delitrix. Buoyant weight data is provided in the "Buoyant_Weight_Data_Submission.xlsx" file.

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.

Coral reef ecosystems are experiencing increased rates of dissolution due to the impacts of ocean acidification (OA) on coral reef calcifiers and bioeroders. Here, we subjected common zooxanthellate (Cliona varians) and azooxanthellate (Pione lampa) Caribbean sponges to four pH treatments: pre-industrial (8.15), present-day (8.05) and two future OA scenarios (7.85 and 7.75). Total bioerosion (buoyant weight), chemical bioerosion, and mechanical bioerosion rates were measured to evaluate trends related to seawater pH. We identified a parabolic relationship between OA and sponge bioerosion, with the highest rates measured in the moderate OA treatment (7.85 pH) and decreasing under the more extreme OA treatment (7.75 pH). This suggests that sponges may become physiologically impaired under prolonged exposure to extreme OA, resulting in diminished bioerosion potential. These data reveal that carbonate dissolution is likely to increase in the upcoming decades as a result of OA-enhanced sponge bioerosion, but that the long-term persistence of reef habitat may benefit from reduced sponge bioerosion under late century OA scenarios.

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.

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.

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 (omega, 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 omega values exceed those anticipated as a consequence 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 contains potential effects of ocean acidification on Alaskan corals based on calcium carbonate mineralogy composition analysis. Effects of ocean acidification (OA) on deep-sea coral habitats in Alaska could be pronounced given the particularly shallow and rapidly shoaling calcite and aragonite saturation horizons in the region. The magnitude of potential effects could partially depend on the corals' calcium carbonate mineralogy. We used X-ray diffraction and powerful full-pattern Rietveld data refinement to precisely determine the skeletal composition of 62 species of Alaskan corals-the most comprehensive cold-water coral dataset for any region of the world. Alaskan corals have complex mineralogy, including a high percentage of slightly polymorphic taxa. Scleractinians and octocorals were principally aragonite and calcite, respectively. A few octocorals were composed of the most soluble form of calcium carbonate (high-Mg calcite). Hydrocorals have the most complex mineralogy with many polymorphic taxa, and some genera have both aragonite and calcite species. Most coral taxa live at least partially below the current saturation horizons so may be physiologically compensating for the effects of OA via important life-history trade-offs. We found evidence of mineral-switching related to depth distribution or broad-scale biogeography. All Alaskan corals are protected by organic tissue and may have the ability to up-regulate the pH of internal calcifying fluid relative to ambient seawater. No Alaskan corals are at risk for skeletal dissolution based on present-day carbonate chemistry conditions in the North Pacific Ocean although the carbonate mineralogy of a few taxa may approach estimated dissolution points. Alaska's ecologically most important corals (Primnoa pacifica and Stylaster spp.) are most at risk to potential effects of OA given their highly soluble skeletons, depth distribution, and observed propensity for tissue loss from contact with fishing gear and predation. Laboratory experiments are currently underway to determine if Primnoa pacifica can tolerate carbonate chemistry conditions predicted for year 2100 and maintain important life-history functions.

These data are from the article “Seasonal carbonate chemistry dynamics on southeast Florida coral reefs: localized acidification hotspots from navigational inlets” published in Frontiers in Marine Science. The data in this package were collected from inlets and reefs along the coast of Southeast Florida. Water was collected bi-monthly from four reefs (Oakland Ridge, Barracuda, Pillars, and Emerald) and three closely-associated inlets (Port Everglades, Bakers Haulover, and Port of Miami). Water samples were collected at these locations either at the surface (~1m depth) or immediately above the benthos measured using a rosette sampler (ECO 55, Seabird). Temperature was recorded at each depth using a CTD (SBE 19V2, Seabird). Turbidity (NTU) was measured at time of water collection. Once collected, water samples were transferred to borosilicate glass bottles, samples were fixed using 200 µL of HgCl2 and sealed using Apiezon grease and a glass stopper. Salinity was measured using a densitometer (DMA 5000M, Anton Paar), while total alkalinity (TA) and dissolved inorganic carbon (DIC) were determined using Apollo SciTech instruments (AS-ALK2 and AS-C3, respectively). All values were measured in duplicate and corrected using certified reference materials following recommendations in Dickson et al. (2007). Aragonite saturation state (ΩArag.), Calcite saturation state (ΩCa), pH (Total scale), and the partial pressure of CO2 (pCO2) were calculated with CO2SYS (Lewis and Wallace, 1998) using the dissociation constants of Mehrbach et al. (1973) as refit by Dickson and Millero (1987) and Dickson (1990). Water samples were reserved for nutrient analyzed at time of collection to determine Total Kjeldahl Nitrogen, Total Phosphorus, and fluorescence of Chlorophyll-a. This research was supported through NOAA’s Coral Reef Conservation Program.

Combining real-time measurements of acidity and calcification, and long-term records from coral skeletons to provide an understanding of how ocean acidity is affecting the marine envrionment and the role of coral reefs in biffering the oceans capacity to absorb greenhouse gas emissions.