Session 5, Abstract 24

INVESTIGATING THE EFFECTS OF DECREASED PH ON AN INTERTIDAL SHORE CRAB, ​HEMIGRAPSUS NUDUS

Avni Gandhi*, Rick Justin Francisco, Madisen Cook, Adrienne Davis and Briana Chavez Vanessa Mendoza (Diara Spain), Dept. of Natural Sciences and Mathematics, Dominican University of California, 50 Acacia Ave, San Rafael, CA 94901

Ocean acidification has emerged as an issue for marine organisms, specifically invertebrates with calcified exoskeletons may be positively or negatively affected by the changes in pH. Our research investigates the potential effect of decreased pH on the weight of Hemigrapsus nudus, an intertidal shore crab in Northern California. The crabs were maintained in individual containers with recirculating chilled seawater at 12.7°C. The control aquarium was at a pH of 8.1, while the experimental aquarium averaged a pH of 7.5 (± 0.1). Crabs were weighed at 2 week intervals over a 6 week period. Initially, most of the crabs decreased in weight. However, in the last 4 weeks the experimental crabs either maintained or had a slight increase in weight, while the control crabs had a larger increase in weight. This difference in weight might indicate that the crabs kept at a lower pH have a lighter exoskeleton with less calcification than those crabs kept at a higher pH.

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