This project is a renewal of an existing ocean acidification (OA) grant supporting an interdisciplinary research team (called OMEGAS) with expertise in oceanography, ecology, biogeochemistry, molecular physiology, and molecular genetics. Research to date has documented a dynamic oceanographic mosaic in the inner shelf of the California Current System (CCS) that spans 1,200+ km and varies at tidal, diurnal, event, and seasonal temporal scales at local to ocean basin spatial scales. In OMEGAS II, the project seeks to better understand the drivers of this striking time-space variability, and to link the OA seascape to the physiological and ecological performance of a key member of this ecosystem, the mussel Mytilus californianus. In addition, the investigators will explore the influence of this oceanographic mosaic on species interactions and community organization. As a dominant habitat-forming species, strong interactor, and major space occupant, M. californianus is arguably the core component of the rocky intertidal ecosystem along the upwelling-dominated CCS. Using an interdisciplinary, spatially extensive approach integrating inner shelf oceanography with ecology, physiology, and eco-mechanics, the interdisciplinary team will study the response of juvenile mussels M. californianus to OA. The studies span levels of biological organization, thereby allowing assessment of how the cost of forming a shell under field conditions might influence physiological performance and resistance to predation. This investigation will include modeling to link to larger-scale ecosystem and oceanographic dynamics in the CCS and beyond.
Results from OMEGAS I show that the growth, survival, and shell strength of mussel larvae are strongly negatively affected by elevated pCO2, and that growth of adult mussels varied among sites within regions and between regions. Emerging data on natural variability in seawater conditions will allow a deeper exploration of the organismal response of M. californianus, and the ecological consequences of traits, such as reduced shell thickness and strength. The present project will expand and strengthen the existing oceanographic network to increase our understanding of the coastal OA regime, and provide the environmental context for ecological and physiological research. Specifically, this project will (1) conduct field and laboratory experiments on the influence of OA on the growth, shell accretion, and resistance to predation of juvenile mussels collected from 10 sites spanning 1,400 km of coastline, (2) link the OA-sensor oceanographic "backbone" to an existing database of community structure via ecological modeling to assess the influence of OA on coastal variation in community organization, (3) determine the physiological responses of juvenile mussels following field deployments and culture under common garden conditions to evaluate mechanistic underpinnings to the responses observed in mussels from different sites, (4) explore the physiological and transcriptomic response of mussels in lab mesocosms to field-documented variability in pCO2, and (5) using modified ROMS models, evaluate the linkage between basin-scale oceanography and local-scale variation in inner-shelf oceanography to evaluate the relative influences of large-to-local scale factors on OA variability. This research aims to understand how coastal ecosystems will respond to OA, and thus to develop our capacity to predict the future impact of OA on coastal ecosystems.
Broader Impacts. This project will leverage complementary funding for research, training and outreach, and engage undergraduates, graduate students, and postdoctoral researchers, as well as PIs. Part of an overall goal is to increase the visibility and familiarity of OA science for policy makers and the general public. Outreach will be facilitated through extensive ties to COMPASS (Communication Partnership for Science and the Sea), public lectures, websites, and multimedia outlets, such as films and television. Each campus is engaged in local-to-national displays on OA.
