Publication Date:
2024-02-02
Description:
We investigated the influences of temperature, salinity and pH on the calcium isotope as well as trace and minor element (uranium, strontium, magnesium) to Ca ratios on calcium carbonate cysts of the calcareous dinoflagellate species Thoracosphaera heimii grown in laboratory cultures. The natural habitat of this species is the photic zone (preferentially at the chlorophyll maximum depth) of temperate to tropical oceans, and it is abundant in deep-sea sediments over the entire Cenozoic. In our experiments, temperatures ranged from 12 to 30 °C, salinity from 36.5 to 38.8 and pH from 7.9 to 8.4. The delta44/40Ca of T. heimii cysts resembles that of other marine calcifiers, including coccolithophores, foraminifers and corals. However, its temperature sensitivity is considerably smaller and statistically insignificant, and T. heimii might serve as a recorder of changes in seawater delta44/40Ca over geologic time. The Sr/Ca ratios of T. heimii cysts show a pronounced temperature sensitivity (0.016 mmol/mol °C**-1) and have the potential to serve as a palaeo-sea surface temperature proxy. No clear temperature- and pH-dependences were observed for Mg/Ca. U/Ca seems to be influenced by temperature and pH, but the correlations change sign at 23 °C and pH 8.2, respectively.
Keywords:
-; BIO; Biology; Center for Marine Environmental Sciences; DEPTH, water; Eastern Mediterranean Sea; Elevation of event; Equatorial Atlantic; Event label; Exchange coefficient; GeoB_strain_116; GeoB_strain_92; Isotope fractionation between growth medium and carbonate; Latitude of event; Longitude of event; M38/2; M40/4; Magnesium/Calcium ratio; MARUM; Meteor (1986); Number; pH; Salinity; Sample code/label; Sample mass; Standard error; Strontium/Calcium ratio; Temperature, technical; Uranium/Calcium ratio; δ44/40 Ca; δ mu Calcium
Type:
Dataset
Format:
text/tab-separated-values, 629 data points
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