Meeting Abstract

P2.129  Sunday, Jan. 5 15:30  Effects of lowered pH on the exoskeleton mineralogy of porcelain crabs PAGE, T. M.*; WORTHINGTON, S.; CALOSI, P.; STILLMAN, J.H.; San Francisco State Univ. ; Univ. of Plymouth, MBERC; Univ. of Plymouth, MBERC; San Francisco State Univ. tpage@sfsu.edu

Ocean acidification (OA) alters biomineralization of calcium carbonate structures across many marine taxa. For example, in mussels and oysters, OA decreases the relative concentration of ions important in calcification, such as calcium and magnesium. OA alters the composition of exoskeletons in crustaceans, such as in prawns, in which Ca:Sr ratio decreased with decreasing pH. However, the effects of reduced pH on biomineralization in arthropod, in particular crab, exoskeletons remains poorly understood. Here, we aimed to test the hypotheses that lowered pH will cause a decrease in minerals found in crab exoskeletons, and lower intertidal species will be more highly affected by pH than higher intertidal species. To accomplish this, we examined exoskeletal composition following 24d of acclimation to pH 8.0, 7.4 and 7.0 in four species of porcelain crab from different intertidal zones and geographic locations. We examined ionic composition ([Ca²⁺], [Mg²⁺], [Mn²⁺], and [Sr²⁺]) of the exoskeleton using Inductively Coupled Plasma Mass Spectrometry. We observed a significant effect of pH on most ion concentrations, [Ca²⁺] had an 18.5% decrease from pH 8.0 to 7.4 in the two higher intertidal species, and a 22% decrease in one of the lower intertidal species. [Mg²⁺] decreased by 16% in two species from pH 8.0 to 7.4, and decreased by 32% from pH 8.0 to 7.0 in another species. [Mn²⁺] increased by 42.86% with decreasing pH in one of the higher intertidal species, however, there was no change in other species. [Sr²⁺] decreased by 43.18% from pH 8.0 to 7.4 in one species. Affect of pH on species origin was found to largely coincide to intertidal zone location. Decreases in ion concentration might negatively affect calcification and/or biomineralization in porcelain crabs.