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.
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.