Publication Date:
2024-03-15
Description:
The Sr/Ca of aragonitic coral skeletons is a commonly used palaeothermometer. However skeletal Sr/Ca is typically dominated by weekly-monthly oscillations which do not reflect temperature or seawater composition and the origins of which are currently unknown. To test the impact of transcellular Ca2+ transport processes on skeletal Sr/Ca, colonies of the branching coral, Pocillopora damicornis, were cultured in the presence of inhibitors of Ca-ATPase (ruthenium red) and Ca channels (verapamil hydrochloride). The photosynthesis, respiration and calcification rates of the colonies were monitored throughout the experiment. The skeleton deposited in the presence of the inhibitors was identified (by 42Ca spike) and analysed for Sr/Ca and Mg/Ca by secondary ion mass spectrometry. The Sr/Ca of the aragonite deposited in the presence of either of the inhibitors was not significantly different from that of the solvent (dimethyl sulfoxide) control, although the coral calcification rate was reduced by up to 66% and 73% in the ruthenium red and verapamil treatments, respectively. The typical precision (95% confidence limits) of mean Sr/Ca determinations within any treatment was 〈±1% and differences in skeletal Sr/Ca between treatments were correspondingly small. Either Ca-ATPase and Ca channels transport Sr2+ and Ca2+ in virtually the same ratio in which they are present in seawater or transcellular processes contribute little Ca2+ to the skeleton and most Ca is derived from seawater transported directly to the calcification site. Variations in the activities of Ca-ATPase and Ca-channels are not responsible for the weekly-monthly Sr/Ca oscillations observed in skeletal chronologies, assuming that the specificities of Ca transcellular transport processes are similar between coral genera.
Keywords:
Alkalinity, Gran titration (Gran, 1950); Alkalinity, total; Alkalinity, total, standard deviation; Animalia; Aragonite saturation state; Benthic animals; Benthos; Bicarbonate ion; Biomass/Abundance/Elemental composition; Bottles or small containers/Aquaria (〈20 L); Calcification/Dissolution; Calcite saturation state; Calculated, see reference(s); Calculated using seacarb after Nisumaa et al. (2010); Carbon, inorganic, dissolved; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Cnidaria; Coast and continental shelf; EPOCA; EUR-OCEANS; European network of excellence for Ocean Ecosystems Analysis; European Project on Ocean Acidification; Experimental treatment; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); ICP-MS, Thermo Scientific, XSeries 2; Identification; Laboratory experiment; Magnesium/Calcium ratio; Magnesium/Calcium ratio, standard deviation; Measured; Net calcification rate of calcium carbonate; OA-ICC; Ocean Acidification International Coordination Centre; Oxygen; Oxygen, standard deviation; Oxygen production rate; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); pH; pH, standard deviation; Pocillopora damicornis; Primary production/Photosynthesis; Red Sea; Replicates; Salinity; Sample ID; Single species; Strontium/Calcium ratio; Strontium/Calcium ratio, standard deviation; Temperate; Temperature, water; Titration, Winkler
Type:
Dataset
Format:
text/tab-separated-values, 1204 data points
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