Publication Date:
2024-03-15
Description:
Ocean acidification can affect the ability of calcifying organisms to build and maintain mineralized tissue. In decapod crustaceans, the exoskeleton is a multilayered structure composed of chitin, protein, and mineral, predominately magnesian calcite or amorphous calcium carbonate (ACC). We investigated the effects of acidification on the exoskeleton of mature (post-terminal-molt) female southern Tanner crabs, Chionoecetes bairdi. Crabs were exposed to one of three pH levels—8.1, 7.8, or 7.5—for two years. Reduced pH led to a suite of body-region-specific effects on the exoskeleton. Microhardness of the claw was 38% lower in crabs at pH 7.5 compared with those at pH 8.1, but carapace microhardness was unaffected by pH. In contrast, reduced pH altered elemental content in the carapace (reduced calcium, increased magnesium), but not the claw. Diminished structural integrity and thinning of the exoskeleton was observed at reduced pH in both body regions; internal erosion of the carapace was present in most crabs at pH 7.5, and the claws of these crabs showed substantial external erosion, with tooth-like denticles nearly or completely worn away. Using infrared spectroscopy, we observed a shift in the phase of calcium carbonate present in the carapace of pH-7.5 crabs: a mix of ACC and calcite was found in the carapace of crabs at pH 8.1, whereas the bulk of calcium carbonate had transformed to calcite in pH-7.5 crabs. With limited capacity for repair, the exoskeleton of long-lived crabs that undergo a terminal molt, such as C. bairdi, may be especially susceptible to ocean acidification.
Keywords:
Alkalinity, total; Alkalinity, total, standard deviation; Animalia; Aragonite saturation state; Arthropoda; Benthic animals; Benthos; Bicarbonate ion; Bicarbonate ion, standard deviation; Biomass/Abundance/Elemental composition; Calcification/Dissolution; Calcite saturation state; Calcite saturation state, standard deviation; Calcium; Calculated using seacarb; Calculated using seacarb after Nisumaa et al. (2010); Carbon, inorganic, dissolved; Carbon, inorganic, dissolved, standard deviation; Carbonate ion; Carbonate ion, standard deviation; Carbonate system computation flag; Carbon dioxide; Category; Chiniak_Bay; Chionoecetes bairdi; Coast and continental shelf; Containers and aquaria (20-1000 L or 〈 1 m**2); EXP; Experiment; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Growth/Morphology; Laboratory experiment; Magnesium; North Pacific; OA-ICC; Ocean Acidification International Coordination Centre; Other studied parameter or process; Partial pressure of carbon dioxide, standard deviation; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); pH; pH, standard deviation; Pollex damage score; Salinity; Salinity, standard deviation; Sample ID; Single species; Species, unique identification; Species, unique identification (Semantic URI); Species, unique identification (URI); Strontium; Temperate; Temperature, water; Temperature, water, standard deviation; Thickness; Treatment: pH; Type of study; v2 peak position, Calcium carbonate; Vickers Hardness
Type:
Dataset
Format:
text/tab-separated-values, 1244 data points
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