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Taxon-specific epibenthic foraminiferal δ18O in the Arctic Ocean: realtionship to water mass, deep circulation, and brine formation

Cited 8 time in wos
Cited 8 time in scopus

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dc.contributor.authorAndreas, Mackensen-
dc.contributor.authorNam, Seung-Il-
dc.coverage.spatialNordic Sea-
dc.date.accessioned2017-08-03T12:51:47Z-
dc.date.available2017-08-03T12:51:47Z-
dc.date.issued2014-
dc.description.abstractWe determined δ<sup>18</sup>O<sub>Cib</sub> values of live (Rose Bengal stained) and dead epibenthic foraminifera<em> Cibicidoides wuellerstorfi, Cibicides lobatulus</em>, and <em>Cibicides refulgens </em>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 δ<sup>18</sup>O<sub>Cib</sub> data set is generated and compiled from the Arctic Ocean. For comparison, we defined Atlantic Water (AW), upper Arctic Bottom Water (uABW), and ABW by their temperature/salinity characteristics and calculated mean equilibrium calcite δ<sup>18</sup>O<sub>equ</sub> from summer sea-water δ<sup>18</sup>O<sub>w</sub> and <em>in situ</em> temperatures accordingly. As a result, in the Arctic environment we compensate for <em>Cibicidoides</em>- and <em>Cibicides</em>-specific offsets from equilibrium calcite of -0.35 and -0.55 ‰, respectively. After this taxon-specific adjustment, mean δ<sup>18</sup>O<sub>Cib</sub> values plausibly reflect the density stratification of principle water masses in the Nordic Sea and Arctic Ocean. In addition, mean δ<sup>18</sup>O<sub>Cib</sub> from AW not only significantly differs from mean δ<sup>18</sup>O<sub>Cib</sub> from ABW, but also δ<sup>18</sup>O<sub>Cib</sub> from within AW differentiates between provenience and water mass age. Furthermore, in shallow waters brine-derived low δ<sup>18</sup>O<sub>w</sub> can significantly lower the δ<sup>18</sup>O<sub>Cib</sub> of <em>Cibicides</em> spp. and thus δ<sup>18</sup>O<sub>Cib</sub> may serve as a paleobrine indicator. There is no statistically significant difference, however, between deeper water masses mean δ<sup>18</sup>O<sub>Cib</sub> of the Nordic Sea, and the Eurasian and Amerasian basins, and no influence of low-δ<sup>18</sup>O<sub>w</sub> brines is recorded in Recent uABW and ABW δ<sup>18</sup>O<sub>Cib</sub> of <em>C. wuellerstorfi.</em> This may be due to dilution of a low-δ<sup>18</sup>O<sub>w</sub> brine signal in the deep sea, and/or to preferential incorporation of high-δ<sup>18</sup>O<sub>w</sub> 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, δ<sup>18</sup>O<sub>Cib</sub> from uABW and ABW do not indicate negative excursions. This may challenge hypotheses that call for enhanced Arctic brine release to explain negative benthic δ<sup>18</sup>O spikes in deep-sea sediments from the late Pleistocene North Atlantic Ocean.-
dc.languageEnglish-
dc.subjectPaleontology-
dc.subject.classificationAraon-
dc.titleTaxon-specific epibenthic foraminiferal δ18O in the Arctic Ocean: realtionship to water mass, deep circulation, and brine formation-
dc.typeArticle-
dc.identifier.bibliographicCitationAndreas, Mackensen, Nam, Seung-Il. 2014. "Taxon-specific epibenthic foraminiferal δ18O in the Arctic Ocean: realtionship to water mass, deep circulation, and brine formation". <em>Marine Micropaleontology</em>, 113(1): 34-43.-
dc.citation.titleMarine Micropaleontology-
dc.citation.volume113-
dc.citation.number1-
dc.citation.page34-43-
dc.identifier.doi10.1016/j.marmicro.2014.09.002-
dc.subject.keywordOxygen isotope-
dc.subject.keywordBrine-
dc.subject.keywordNordic Sea-
dc.subject.keywordProxy-
dc.subject.keywordPleistocene-
dc.subject.keywordAraon-
dc.subject.keywordR/V Polarstern-
dc.identifier.scopusid2-s2.0-84907812581-
dc.identifier.wosid000345879400004-
Appears in Collections  
2014-2016, Characteristics of gas hydrate and reconstruction of paleo-environment changes in the western Arctic (14-16) / Nam, Seung-Il (PE14062; PE15062; PE16062)
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