Stable oxygen isotope record of epibenthic foraminifera and water samples of the Arctic Ocean


Autoria(s): Mackensen, Andreas; Nam, Seung-Il
Cobertura

MEDIAN LATITUDE: 77.916956 * MEDIAN LONGITUDE: 159.689137 * SOUTH-BOUND LATITUDE: 65.845000 * WEST-BOUND LONGITUDE: 1.108170 * NORTH-BOUND LATITUDE: 88.512000 * EAST-BOUND LONGITUDE: -4.066667 * DATE/TIME START: 1988-06-02T00:00:00 * DATE/TIME END: 2012-08-01T00:00:00

Data(s)

22/10/2014

Resumo

We determined d18OCib values of live (Rose Bengal stained) and dead epibenthic foraminifera Cibicidoides wuellerstorfi, Cibicides lobatulus, and Cibicides refulgens in surface sediment samples from the Arctic Ocean and the Greenland, Iceland, and Norwegian seas (Nordic Sea). This is the first time that a comprehensive d18OCib data set is generated and compiled from the Arctic Ocean. For comparison, we defined Atlantic Water (AW), upper Arctic Bottom Water (uABW), and Arctic Bottom Water (ABW) by their temperature/salinity characteristics and calculated mean equilibrium calcite d18Oequ from summer sea-water d18Ow and in situ temperatures. As a result, in the Arctic environment we compensate for Cibicidoides- and Cibicides-specific offsets from equilibrium calcite of -0.35 and -0.55 per mil, respectively. After this taxon-specific adjustment, mean d18OCib values plausibly reflect the density stratification of principle water masses in the Nordic Sea and Arctic Ocean. In addition, mean d18OCib from AW not only significantly differs from mean d18OCib from ABW, but also d18OCib from within AW differentiates in function of provenience and water mass age. Furthermore, in shallow waters brine-derived low d18Ow can significantly lower the d18OCib of Cibicides spp. and thus d18OCib may serve as a paleobrine indicator. There is no statistically significant difference, however, between deeper water masses mean d18OCib of the Nordic Sea, and of the Eurasian and Amerasian basins, and no influence of low-d18Ow brines is recorded in Recent uABW and ABW d18OCib of C. wuellerstorfi. This may be due to dilution of a low-d18Ow brine signal in the deep sea, and/or to preferential incorporation of relatively high-d18Ow brines from high-salinity shelves. Although our data encompass environments with seasonal sea-ice and brine formation supposed to ultimately ventilate the deep Arctic Ocean, d18OCib from uABW and ABW do not indicate negative excursions. This may challenge hypotheses that call for enhanced Arctic brine release to explain negative benthic d18O spikes in deep-sea sediments from the late Pleistocene North Atlantic Ocean.

Formato

application/zip, 2 datasets

Identificador

https://doi.pangaea.de/10.1594/PANGAEA.837010

doi:10.1594/PANGAEA.837010

Idioma(s)

en

Publicador

PANGAEA

Direitos

CC-BY: Creative Commons Attribution 3.0 Unported

Access constraints: unrestricted

Fonte

Supplement to: Mackensen, Andreas; Nam, Seung-Il (2014): Taxon-specific epibenthic foraminiferal d18O in the Arctic Ocean: Relationship to water masses, deep circulation, and brine release. Marine Micropaleontology, 113, 34-43, doi:10.1016/j.marmicro.2014.09.002

Palavras-Chave #0 = live, 4 = dead, 1 = undetermined; AWI_Paleo; Calculated; Cibicidoides spp., d18O; Cibicidoides spp. d18O; d18O; d18Oequ vs. VPDB; d18O H2O; delta 18O; delta 18O, water; Depth; DEPTH, sediment/rock; DEPTH, water; Depth water; Event; Flag; Mass spectrometer Finnigan Delta-S/equilibration device; Mass spectrometer Finnigan MAT 251 and Finnigan MAT 253; Paleoenvironmental Reconstructions from Marine Sediments @ AWI; Quality flag; Sal; Salinity; Temp; Temperature, water; vs. VPDB; Cibicidoides wuellerstorfi, if C. wuellerstorfi specimens were not available Cibicides lobatulus and Cibicides refulgens were analyzed; size fraction >125 µm
Tipo

Dataset