| Summary: | Samuel J. Gurr 1 *, Shelly A. Trigg 3 , Brent Vadopalas 2 , Steven B. Roberts 3 , Hollie M. Putnam 1 1 University of Rhode Island, College of the Environment and Life Sciences, 120 Flagg Rd, Kingston, RI 02881 USA 2 University of Washington, Washington Sea Grant, 3716 Brooklyn Ave NE, Seattle, WA 98105 USA 3 University of Washington, School of Aquatic and Fishery Sciences, 1122 NE Boat St, Seattle, WA 98105 USA Moderate oxidative stress is a hypothesized driver of enhanced adaptive capacity and lifespan. Whereas thermal stress, irradiance, and dietary restriction show evidence of dose-dependent benefits for terrestrial vertebrates, the importance of stress acclimation remains understudied for establishment of enhanced stress response in marine ectotherms. Marine invertebrates of commercial and ecological importance are threatened by elevated p CO 2 and aragonite undersaturation. Stress acclimation may drive phenotypic variation advantageous for sustainable aquaculture of long-lived mollusc species such as the Pacific geoduck Panopea generosa . To test for lifestage and stress-intensity dependence in eliciting enhanced tolerance under subsequent stress encounters, we acclimated ~30 day old pediveliger geoduck larvae for 110 days to 1) an initial exposure of ambient and moderately elevated p CO 2 (920 µatm >1 Ω and 2800 µatm 0.4 Ω, respectively). We then exposed them to 2) an acute 7-day secondary exposure to ambient, moderate, and severely elevated p CO 2 conditions (750 µatm >1 Ω, 2800 µatm 0.4 Ω, and 4900 µatm 0.2 Ω, respectively). Clams were returned to ambient p CO 2 for 7 days and then subject to 3) a 7-day tertiary exposure to ambient and moderately elevated p CO 2 conditions (970 µatm >1 Ω and 3000 µatm 0.4 Ω, respectively) in a modified-reciprocal design. Throughout each exposure, we measured metrics of physiological performance (respiration rate, shell growth, total protein and organic biomass) and cellular stress response (total antioxidant capacity). Initial exposure to moderate pCO2 stress ...
|
|---|