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.
Coastal acidification and its associated co-stressors present a serious and credible threat to the success of both oyster aquaculture and restoration in the Chesapeake Bay. Recent research provides a clearer understanding of the physiological sensitivity of different economically and culturally valuable shellfish species to ocean acidification (OA), but we still lack a basic understanding of how vulnerability differs across the range of shellfish-reliant stakeholders, specifically participants in oyster aquaculture, the growers, watermen and coastal restoration managers. This basic knowledge gap motivates this work, which aims to: (1) assess the vulnerability of the oyster aquaculture industry and oyster restoration to OA and other co-stressors, and (2) produce the information required by regional communities to aid in adaptation to these stressors. In achieving these goals, we will better understand which shellfish stakeholders will be able to successfully adapt, which will seek alternative livelihoods, and what specifically causes the difference between these two disparate outcomes.
Acidification in brackish estuarine environments, such as the Chesapeake Bay, is intensified by coastal inputs such as runoff, atmospheric pollution and freshwater sources. The Chesapeake Bay is home to commercial shellfish hatcheries that supply seed that is sold to and planted in hundreds of shellfish farms within the Chesapeake. A great deal of research has been dedicated to understanding the impact of acidification on shellfish, and has shown even greater impacts to shellfish growth and survival in lower salinity and nutrient-rich environments. The shellfish industry relies on consistent hatchery production to sustain and expand operations that could greatly benefit from regional OA forecasts and metrics. This project will synthesize recent CO2 system observations with long-term water quality parameters and combine observations an existing baywide, high-resolution 3D model. The proposed research will develop forecasts of acidification and develop acidification metrics tailored to support decision-making needs of commercial shellfish hatchery and nursery operators.
NOAA academic partners Salisbury and Cai will organize and lead a 34-days cruise covering 12 transects of the U.S. and Canadian coast oceans from Nova Scotia in the north to the Gulf of Maine, Long Island Sound, Mid-Atlantic and Southern Bight regions, ending with a transect off of mid Florida. This cruise will serve as a synoptic characterization of the marine carbonate parameters of the coastal ocean with increased coverage in nearshore areas that have not surveyed in the previous cruises and subsurface dynamics that are not captured from using buoyed assets or ships of opportunity. The climate quality data from these cruises provide an important link to the Global Ocean Acidification Network (GOAN) effort, and serves as a start of a long-term record of dynamics and processes controlling Ocean Acidification (OA) on the coastal shelves. To this end there is an increasing focus on these cruises to perform rate measurements (e.g. NPP/NEP/NEC) for validation measurements of autonomous assets and buoyed assets, for algorithm development utilizing remotely sensed signals that are used to characterize saturation states, and to project the future state of ocean acidification in the project area.
This project will provide service and maintenance of sensors and ground-truthing of the mooring data at the Gray's Reef OA monitoring site, as well as data quality control and synthesis. Specifically, we will accomplish the follow three tasks: 1. Deployment and maintenance of the sensors (pCO2, pH, and dissolved oxygen); 2. Collection of underway pCO2 data and bulk water samples for analyses using ship-of-opportunity and dedicated cruises about four times a year; and 3. Data quality control and data synthesis.
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.
Dedicated research cruises are used to obtain subsurface measurements and a comprehensive suite of biogeochemical observations to gain a process level understanding of OA. OAP provides funds to carry out the Gulf of Mexico and East Coast Carbon (GOMECC) research cruises every 5 years. These cruises provide a data set of unprecedented quality of physical and chemical coastal ocean parameters that is used both for improved spatial understanding of OA and also to provide a general understanding of changing patterns over time by comparison with previous cruises. The monitoring component is an essential part of the OAP, providing a long-term assessment of changes of biogeochemistry and ecology in response to increasing CO2 atmospheric levels and large-scale changes in coastal dynamics.
The climate quality data from the research cruises provide an important link to the Global Ocean Acidification Network (GOAN) effort, and contribute to a long-term record of dynamics and processes controlling OA on the coastal shelves. The data are used for validation measurements of autonomous assets, applying the data for algorithm development utilizing remotely sensed signals that are used to characterize saturation states, and to project the future state of ocean acidification in the project area.