In 2010 and 2011, Alaska Fisheries Science Center (AFSC) scientists at the Kodiak Laboratory in Alaska tested the effects of lower pH due to increased carbon dioxide (CO₂) on the survival, condition, and growth of red king crab (Paralithodes camtschaticus). Commercially important shellfish are a priority for AFSC research related to ocean acidification because of their economic value and because calcifying species are likely to suffer direct effects due to increased acidity (and a decrease in calcium carbonate saturation state) of our oceans.

The multi-year project objectives are to test the effects of CO₂ enrichment (which leads to decreasing pH and lower saturation state) across a range of commercially important crab species and life stages (embryo, larvae, juveniles, and adults). The response variables currently measured include mortality, condition, growth, and calcification of the shell.

The California Current is a dynamic eastern boundary system that spans the Northeast Pacific from Canada to Baja California, Mexico. Upwelling of cold, nutrient rich water drives multi trophic level productivity throughout much of the domain, but also results in naturally acidic on-shelf waters on regional scales. In addition, anthropogenic CO2 on basin to global scales, and local inputs by eutrophication, fresh water inputs, and local respiration or carbon assimilation result in multiscale and context-specific perturbations to the carbonate system. Thus, to understand, manage, or mitigate the effect of ocean acidification on ocean ecosystems, we need to quantify a suite of carbonate system parameters along the Pacific Coast in a mechanistic, spatially explicit, and temporally dynamic fashion.

We propose to embed an improved semi-analytical carbonate-chemistry prediction model within a dynamic classification of pelagic seascapes derived from satellite remotely sensed variables, including, but not limited to, phytoplankton standing stock (chl-a), SST, and wind stress. We will produce synoptic time series and nowcasts of surface TCO2, TALK, pH and Ω that will facilitate regional comparisons of interannual trends in OA parameters. We will include metrics of model and spatiotemporal uncertainty to better inform management decisions. These maps will be validated with the wealth of multi-parameter OA data generated from recent NOAA-supported field-observational efforts, from coastal moorings, West-coast OA cruises, and shore-based Burke-o-Lators. Statistical analyses will quantify spatially explicit trends across OA parameters, and local deviations from seascape-based predictions will disentangle basin-scale oceanic vs. local drivers of the carbonate system. Maps will be served in near real time on IOOS data portals. Time series and maps will inform marine ecosystem management and provide metrics of ocean health for National Marine Sanctuary condition reports.

This project will provide time-series observations of coastal ocean pH and carbon system properties, along with other variables that affect carbon transformations, in the northern Gulf of Mexico in support of goals elucidated in the NOAA Ocean and Great Lakes Acidification Research Implementation Plan. This project most directly addresses Theme 1: Develop the monitoring capacity to quantify and track ocean acidification in open-ocean, coastal, and Great Lake systems, but also addresses the educational objectives of Theme 6. USM will maintain a 3- m discus buoy in the northern Gulf of Mexico with a PMEL MAPCO2 system that includes a CTD, dissolved oxygen, and pH sensors. Meteorological sensors on the buoy will be utilized for computing air-sea fluxes of CO2. Water samples and continuous vertical profiles will be taken at the buoy site during quarterly cruises. Water samples will be analyzed for DIC, TA, pH, dO, S, NUTS and chlorophyll a. Analyzed water samples and profile data will be submitted to NODC through standard NOAA OAP submission spreadsheets containing both data and associated metadata.

While this work is focused on the Gulf of Mexico additional time-series sites in the South Atlantic Bight and Gulf of Maine can provide a comparison over a wide range of coastal and latitudinal regimes. The northern Gulf of Mexico, Florida and South Atlantic Bight regions are all commonly influenced by one contiguous western boundary current system, which originates with the Loop Current in the Gulf of Mexico and then becomes the Gulf Stream along the southeastern U.S. continental shelf. The Gulf of Mexico observations will be compared with the other western boundary current influenced site in the South Atlantic Bight maintained by the University of Georgia (UGA) and the high latitude site in the Gulf of Maine maintained by the University of New Hampshire (UNH). 

Analysis of the data collected during the first (2007) and the second (2012) Gulf of Mexico and East Coast Carbon (GOMECC) cruises showed measurable temporal pH and aragonite saturation state (ΩAr) changes along the eight major transects. However, it is challenging to determine how much of this temporal change between the two cruises is due to ocean acidification and how much is due to variability on seasonal to interannual scales. Indeed, the expected 2% average decrease in ΩAr due to increasing atmospheric CO2 levels over the 5-year period was largely overshadowed by local and regional variability from changes in ocean circulation, remineralization/respiration and riverine inputs (Wanninkhof et al., 2015). Therefore, in order to provide useful products for the ocean acidification (OA) research community and resource managers, it is important to filter out seasonal cycles and other variability from the multi-annual trend. Here, we propose to use a high-resolution regional ocean-biogeochemistry model simulation for the period of 1979 - present day (real-time run) to fill the temporal gap between the 1st and 2nd GOMECC cruise data. In addition we will fine-tune and validate the model by using extensive surface water pCO2 observations from the ships of opportunity in the coastal region (SOOP-OA), and using the carbon observations from the East Coast Ocean Acidification Cruises (ECOA-1) and OAP mooring stations and from remotely sensed data. Then, we will use the real-time model run to estimate the 5-year trends (2012 – 2007) of OA and the carbon and biogeochemical variables along the East and Gulf coasts of the U.S. We will also examine the future OA variability in the East and Gulf coasts of the U.S. by downscaling the future climate projections under different emission scenarios developed for the IPCC-AR5. Based on the results obtained from the proposed model simulations, we will contribute to an observational strategy suitable for elucidating multi-annual trend of carbon and biogeochemical variables along the East and Gulf coasts of the U.S.

NOAA operates the largest ship of opportunity (SOOP) effort for surface CO2 observations in the world. The objective of the ocean acidification (OA) monitoring effort in the coastal ocean on NOAA fisheries ships Gordon Gunter and Henry B. Bigelow is to obtain data for a data-based ocean acidification product suite for the East Coast and Gulf Coast. The ship of opportunity (SOOP) in support of OA monitoring (SOOP-OA) is in direct response to the needs expressed in the NOAA OA strategic plan, national and international program documentation, to understand how the rates and magnitude of acidification will vary across time and space, as a consequence of local and regional geochemical, hydrological, and biological variability and trends. The core of understanding rests upon monitoring the carbon system and related physical and biogeochemical parameters that are used to characterize the state of the coastal ocean in the project area. 

The NOAA fisheries ships Gunter and Bigelow provide regular cruise tracks used in stock assessments such that over time correlations and causality can be obtained between OA and fisheries interests. The repeatability also provides good snapshots of change. As there are robust correlations between surface CO2 levels and remotely sensed parameters, these data are critical for the mapping of OA parameters. The development of algorithms to perform this mapping is done from support measurements on the SOOP-OA, other SOOP data under our purview, and from the dedicated research cruises.