Calcium isotopic composition of high-latitude proxy carrier Neogloboquadrina pachyderma (sin.)

Hippler, Dorothee; Kozdon, Reinhard; Darling, Kate F.; Eisenhauer, Anton; Nägler, Thomas F. (2009). Calcium isotopic composition of high-latitude proxy carrier Neogloboquadrina pachyderma (sin.). Biogeosciences, 6(1), pp. 1-14. Göttingen: Copernicus Publications 10.5194/bg-6-1-2009

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The accurate reconstruction of sea surface temperature (SST) history in climate-sensitive regions (e.g. tropical and polar oceans) became a challenging task in palaeoceanographic research. Biogenic shell carbonate SST proxies successfully developed for tropical regions often fail in cool water environments. Their major regional shortcomings and the cryptic diversity now found within the major high latitude proxy carrier Neogloboquadrina pachyderma (sin.) highlight an urgent need to explore complementary SST proxies for these cool-water regions. Here we incorporate the genetic component into a calibration study of a new SST proxy for the high latitudes. We found that the calcium isotopic composition (δ44/40Ca) of calcite from genotyped net catches and core-top samples of the planktonic foraminifera Neogloboquadrina pachyderma (sin.) is related to temperature and unaffected by genetic variations. The temperature sensitivity has been found to be 0.17 (±0.02)‰ per 1°C, highlighting its potential for downcore applications in open marine cool-water environments. Our results further indicate that in extreme polar environments, below a critical threshold temperature of 2.0 (±0.5)°C associated with salinities below 33.0 (±0.5)‰, a prominent shift in biomineralization affects the δ44/40Ca of genotyped and core-top N. pachyderma (sin.), becoming insensitive to temperature. These findings highlight the need of more systematic calibration studies on single planktonic foraminiferal species in order to unravel species-specific factors influencing the temperature sensitivity of Ca isotope fractionation and to validate the proxies' applicability.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Institute of Geological Sciences

UniBE Contributor:

Nägler, Thomas

ISSN:

1726-4170

Publisher:

Copernicus Publications

Language:

English

Submitter:

Thomas Nägler

Date Deposited:

04 Oct 2013 15:25

Last Modified:

08 Dec 2014 19:17

Publisher DOI:

10.5194/bg-6-1-2009

Web of Science ID:

000262902700001

BORIS DOI:

10.7892/boris.38566

URI:

https://boris.unibe.ch/id/eprint/38566 (FactScience: 222422)

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