This project will serve to (1) synthesize National Coral Reef Monitoring Program (NCRMP) OA Enterprise observations; (2) compare reef OA observations to oceanic end members to infer reefscale biogeochemical processes, and finally (3) use these synthesis products to better link projection models of oceanic carbonate systems to reef-scale OA impacts. The NCRMP OA enterprise supports: our collection of seawater samples from reef and surface observations; a set of MapCO2 buoys in the Caribbean and Hawaii; diurnal monitoring instruments (e.g. CREP's diurnal suite, AOML's/McGillis' BEAMS); and metrics of ecosystem response to OA (e.g. CAUs, coral coring, etc.). The datasets generated by these activities will be the focus of this wide-ranging synthesis.

The goal of this project is to improve our understanding of the effects of ocean acidification and warming on coral reef communities by examining responses of entire suites of reef organisms recruiting to Autonomous Reef Monitoring Structures (ARMS) in benthic mesocosms. We will perform a fully factorial experiment that consists of four treatments of low and high temperature and pCO₂ levels. ARMS are the leading long-term monitoring tool to measure biodiversity on reef systems and are integrated into the National Coral Reef Monitoring Program (NCRMP) Class II and Class III climate stations dedicated to monitor and access the physical, chemical and biological impacts associated with climate change over time. We propose to examine the effects of elevated temperature and pCO₂ on recruitment, biomass, biodiversity, and community structure over a multiannual time frame to increase our understanding of how biodiversity, ecosystem function, and their relationship will be impacted under future climate scenarios. 

Deep-sea corals are widespread throughout Alaska, including the continental shelf and upper slope of the Gulf of Alaska, the Aleutian Islands, the eastern Bering Sea, and extending as far north as the Beaufort Sea. Decreases in oceanic pH and resulting decreases in calcium carbonate saturation state could have profound effects on corals dependent on the extraction of calcium carbonate from seawater for skeletal building. Corals will be affected differently depending on their skeletal composition (aragonite vs. calcite), geographical location, and depth. The aragonite and calcite saturation horizons are already quite shallow in areas of the North Pacific Ocean and are predicted to become shallower in the near future. The skeletal composition is known for only a few Alaskan coral species and may be composed of aragonite, calcite, high-magnesium calcite, or amorphous carbonate hydroxylapatite. Skeletons composed of high magnesium-calcite are the most soluble and consequently corals with high-magnesium calcite skeletons, particularly those residing at depths deeper than the saturation horizon, are most at risk to decreases in oceanic pH. At the completion of this project we will be able to provide a comprehensive risk assessment for all corals in Alaskan waters.

To date many studies of the effects of ocean acidification on fishes have suggested that fish are somewhat resilient to effects on factors such as growth and survival. However, these experiments have generally not included potential interactive stressors which may increase the sensitivity to acidification stress. Further, experiments on some species have demonstrated the OA stress has significant potential to disrupt sensory and behavioral systems in fishes which could compromise survival in natural settings. In this project we will focus on examining the potential for behavioral disruptions due to OA and the interactive stresses of OA and nutritional state on critical Alaskan groundfishes.

The aim of this project was to forecast effects of ocean acidification on the commercially important Alaska crab stocks including the Bristol Bay red king crab (BBRKC) fishery, which is part of a modern fisheries management program, the Bering Sea and Aleutian Islands (BSAI) crab rationalization program. To investigate the biological and economic impacts of OA, a linked bioeconomic model was developed that a) integrates predictions regarding trends over time in ocean pH, b) separates life-history stages for growth and mortality of juveniles and adults, and c) includes fishery impacts by analyzing catch and effort in both biological and economic terms. By coupling a pre-recruitment component with post-recruitment dynamics, the BBRKC bioeconomic model incorporates effects of OA on vulnerable juvenile crabs in combination with effects of fishing on the BBRKC population as a whole. Many types of projections under management strategies can be made using linked bioeconomic models.

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.

We will examine the effects of OA conditions (elevated pCO2) on the adaptive response of a potentially vulnerable native marine mollusc species with ecological, economic and social importance in the Pacific Northwest: geoduck clams (Panopea generosa).  Geoduck clam larvae will be exposed to normal and elevated pCO2 and surviving larvae will be assessed using genomic sequencing to determine changes in allele frequencies at single nucleotide polymorphisms throughout the genome, and changes in the frequency of methylation states (epialleles) throughout the epigenome.  Existing ecosystem models of OA consider a species' response to increased pCO2 as a fixed attribute; however, interpretations of the effects of OA at the population level may shift substantially if species adapt to the new environment. Furthermore, we will gain a better understanding of how specific genetic and epigenetic variations influence phenotype and the ability of an organism to respond, giving us new insights into fundamental aspects of species adaptation to environmental change.

Assessing a species’ risk to ocean acidification (OA) will depend on their duration of exposure to low pH/low saturation state conditions and their sensitivity to low pH conditions. Lab species exposure experiments attempt to measure species sensitivity to low pH. This modeling project estimates species exposure. In FY13, we started using an existing circulation/water quality of model of the Salish Sea and Washington/B.C. Coasts developed by the Pacific Northwest National Laboratory to understand carbonate chemistry exposure of zooplankton species. We are using empirical relationships between carbonate chemistry, oxygen, temperature and salinity to add carbonate chemistry to the circulation model. We then use an individually-based model to simulate the movement of various zooplankton species in this environment. In FY15-FY17, we will continue development and publication of results from this model, including exploration of current and future CO2 scenarios. Results from the model will inform the Dungeness crab exposure experiments planned for FY16, as well as general zooplankton vulnerability to OA.

Ecosystem models are used to estimate the potential direct and indirect effects of ocean acidification (OA) on marine resources.  The population abundance and distribution of species that are sensitive to seawater carbonate chemistry can experience the direct effects of OA. Even species not sensitive to carbonate chemistry can have indirectly changes in abundance and distribution as a result of changes in their prey, predators, competitors or critical habitat forming organisms that are sensitive. Ecosystem models use information on food webs and other relationships to estimate these ripple effects of OA on important ecosystem services like fisheries.

Species exposure experiments that measure the response of organisms reared in seawater with manipulated carbonate chemistry are an important way to learn about the potential effects of ocean acidification (OA). Experimental systems that closely mimic the natural environment (e.g. with multiple stressors) can lead to studies with greater ecological relevance. Using a combination of NWFSC and OAP funds, the NWFSC built a facility for conducting species exposure experiments at the Montlake Lab, and has started a new facility at the Mukilteo Field station. The facilities include both rearing aquaria and a lab for carbon chemistry analysis (DIC, alkalinity, spectrophotometric pH). The NWFSC experimental systems are considered “shared-use” facilities, in that the systems are available for NWFSC research teams and outside collaborators as capacity allows. In the past, we have worked on collaborative projects with PMEL, University of Washington, Oregon State University, Suquamish Tribe, Evergreen State University, Cal Poly and Western Washington University. These collaborators often provide external funding for experiments, greatly increasing the research that can be conducted.