Adult snow crab, Chionoecetes opilio, display body-wide exoskeletal resistance to the effects of long-term ocean acidification

• Published in: Marine biology 2023-05, Vol.170 (5), p.63, Article 63
• Main Authors: Algayer, Tait, Mahmoud, Ahmed, Saksena, Sanjana, Long, W. Christopher, Swiney, Katherine M., Foy, Robert J., Steffel, Brittan V., Smith, Kathryn E., Aronson, Richard B., Dickinson, Gary H.
• Format: Article
• Language: English
• Subjects: Abiotic factors; Acidification; Aquatic crustaceans; Biomedical and Life Sciences; Body regions; Calcification; Calcium; Carapace; Chemical composition; Chionoecetes opilio; Claws; Crabs; Crustaceans; Environmental aspects; Exoskeleton; Exoskeletons; Freshwater & Marine Ecology; Latitude; Life Sciences; Locomotion; Magnesium; Marine & Freshwater Sciences; Marine biology; Marine crustaceans; Mechanical properties; Microbiology; Microhardness; Molting; Ocean acidification; Oceanography; Oceans; Original Paper; pH effects; Physiological aspects; Seawater; Shellfish; Thickness; Vulnerability; Zoology
• ISSN: 0025-3162; 1432-1793
• DOI: 10.1007/s00227-023-04209-0

Structural and mechanical properties of the decapod exoskeleton affect foraging, defense, and locomotion. Ocean acidification (OA) poses a threat to marine biomes and their inhabitants, particularly calcifying organisms. Vulnerability of the snow crab, Chionecetes opilio , a commercially important, high-latitude species, to OA has not been explored. Although all oceans are experiencing acidification, abiotic factors in high-latitude areas increase the rate of acidification. We examined the effect of long-term (2 year) exposure to decreased seawater pH (7.8 and 7.5, P CO2  ~ 760 and 1550 µatm, respectively) on exoskeletal properties in post-terminal-molt female C. opilio . Since the effects of OA vary among body regions in decapods, exoskeletal properties (microhardness, thickness, and elemental composition) were measured in five body regions: the carapace, both claws, and both third walking legs. Overall, adult C. opilio exoskeletons were robust to OA in all body regions. Decreased pH had no effect on microhardness or thickness of the exoskeleton, despite a slight (~ 6%) reduction in calcium content in crabs held at pH 7.5. In contrast, exoskeletal properties varied dramatically among body regions regardless of pH. The exoskeleton of the claws was harder, thicker, and contained more calcium but less magnesium than that of other body regions. Exoskeleton of the legs was thinner than that of other body regions and contained significantly greater magnesium concentrations (~ 2.5 times higher than the claws). Maintenance of exoskeletal properties after long-term OA exposure, at least down to pH 7.5, in adult C. opilio suggests that wild populations may tolerate future ocean pH conditions.