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.