Benthic Foraminiferal Mg/Ca and Sr/Ca Presented Under Varying Population Densities on the Southeastern United States Continental Shelf
Abstract
Unraveling the inherent variabilities in benthic foraminiferal Mg/Ca and other trace elements will help produce a more refined temperature proxy for benthic foraminiferal calcification temperature. To date, proxy signature variability in field samples has been attributed to microhabitat and poorly understood vital effects. Vital effects such as food supply, calcification rate, metabolic rate, may influence microhabitat chemistry or foraminiferal shell chemistry, but are difficult to measure. However, easily measurable benthic population densities and abundances are likely to be driven by food supply, and may also be controlled by foraminiferal calcification or metabolic rates. Mg/Ca and Sr/Ca from live core-top benthic foraminfera were investigated to test whether vital effect factors, as reflected by faunal abundance and diversity, influence foraminiferal element/calcium ratios. Foraminiferal element/calcium ratios are presented along with corresponding abundances and species diversities of cores collected in 2001, 2005, and 2006 from the shallow-slope environ of the Charleston Bump (31° 55'N, 79° 11'W; ~220m water depth; temp range: 9.4-11.2° C; calcite saturation state: 2.29- 2.73). Overall total foraminiferal population densities increased by 6 fold in the more recent years (2001, n=350, 6.1 individuals/cm3; 2005, n>2300, 40 individuals/cm3; 2006, n>1900, 33.6 individuals/cm3). If a correlation exists between benthic foraminiferal population densities and element/calcium ratios, then this may suggest that biological processes can affect foraminiferal element/calcium shell chemistry. Funded by NSF OCE9911654, OCE0351029, and OCE 0437366.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2006
- Bibcode:
- 2006AGUFMPP21C1699B
- Keywords:
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- 3030 Micropaleontology (0459;
- 4944);
- 4804 Benthic processes;
- benthos (0408);
- 4875 Trace elements (0489);
- 4924 Geochemical tracers;
- 4928 Global climate models (1626;
- 3337)