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  • 2010-2014  (6)
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  • 1
    Publication Date: 2022-05-25
    Description: Author Posting. © American Geophysical Union, 2012. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Paleoceanography 27 (2012): PA2207, doi:10.1029/2011PA002244.
    Description: At the peak of the previous interglacial period, North Atlantic and subpolar climate shared many features in common with projections of our future climate, including warmer-than-present conditions and a diminished Greenland Ice Sheet (GIS). Here we portray changes in North Atlantic hydrography linked with Greenland climate during Marine Isotope Stage (MIS) 5e using (sub)centennially sampled records of planktonic foraminiferal isotopes and assemblage counts and ice-rafted debris counts, as well as modern analog technique and Mg/Ca-based paleothermometry. We use the core MD03-2664 recovered from a high accumulation rate site (∼34 cm/kyr) on the Eirik sediment drift (57°26.34′N, 48°36.35′W). The results indicate that surface waters off southern Greenland were ∼3–5°C warmer than today during early MIS 5e. These anomalously warm sea surface temperatures (SSTs) prevailed until the isotopic peak of MIS 5e when they were interrupted by a cooling event beginning at ∼126 kyr BP. This interglacial cooling event is followed by a gradual warming with SSTs subsequently plateauing just below early MIS 5e values. A planktonic δ18O minimum during the cooling event indicates that marked freshening of the surface waters accompanied the cooling. We suggest that switches in the subpolar gyre hydrography occurred during a warmer climate, involving regional changes in freshwater fluxes/balance and East Greenland Current influence in the study area. The nature of these hydrographic transitions suggests that they are most likely related to large-scale circulation dynamics, potentially amplified by GIS meltwater influences.
    Description: This work is a contribution of the European Science Foundation EuroMARC program, through the AMOCINT project, funded through grants from the Research Council of Norway (RCN) and contributes to EU-FP7 IP Past4Future. N. Irvalı was additionally funded by an ESF EUROCORES Short-term Visit grant and a RCN Leiv Eiriksson mobility grant to support research stays at the University of Edinburgh, UK, and Woods Hole Oceanographic Institution, USA, respectively, during which parts of the data for this paper were acquired. U. Ninnemann was funded by a University of Bergen Meltzer research grant.
    Description: 2012-11-12
    Keywords: Eirik Drift ; MIS 5e ; North Atlantic ; Last interglacial ; Multiproxy
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
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  • 2
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    PANGAEA
    In:  Supplement to: Bauch, Dorothea; Darling, Kate F; Simstich, Johannes; Bauch, Henning A; Erlenkeuser, Helmut; Kroon, Dick (2003): Palaeoceanographic implications of genetic variation in living North Atlantic Neogloboquadrina pachyderma. Nature, 424(6946), 299-303, https://doi.org/10.1038/nature01778
    Publication Date: 2024-07-01
    Description: The shells of the planktonic foraminifer Neogloboquadrina pachyderma have become a classical tool for reconstructing glacial-interglacial climate conditions in the North Atlantic Ocean. Palaeoceanographers utilize its left- and right-coiling variants, which exhibit a distinctive reciprocal temperature and water mass related shift in faunal abundance both at present and in late Quaternary sediments. Recently discovered cryptic genetic diversity in planktonic foraminifers now poses significant questions for these studies. Here we report genetic evidence demonstrating that the apparent 'single species' shell-based records of right-coiling N. pachyderma used in palaeoceanographic reconstructions contain an alternation in species as environmental factors change. This is reflected in a species-dependent incremental shift in right-coiling N. pachyderma shell calcite d18O between the Last Glacial Maximum and full Holocene conditions. Guided by the percentage dextral coiling ratio, our findings enhance the use of d18O records of right-coiling N. pachyderma for future study. They also highlight the need to genetically investigate other important morphospecies to refine their accuracy and reliability as palaeoceanographic proxies.
    Keywords: 104-1; 111-2; 114-1; 117-1; 120-1; 271; 61-1; Aegir Ridge, Norwegian-Greenland Sea; Arctic Ocean; ARK-I/3; ARK-II/4; ARK-II/5; ARK-III/3; ARK-IX/3; ARK-X/1; ARK-X/2; Atlantic Ocean; BS88/6_10B; BS88/6_4; BS88/6_8; CTD/Rosette; CTD-RO; Denmark Strait; East Greenland Sea; Fram Strait; Giant box corer; GIK16301-1; GIK16302-1; GIK16304-1; GIK16305-1; GIK16306-3; GIK21291-3 PS07/581; GIK23000-2; GIK23008-1; GIK23016-1; GIK23019-1; GIK23022-1; GIK23027-1; GIK23037-1; GIK23038-1; GIK23039-1; GIK23041-1; GIK23042-1; GIK23043-1; GIK23055-1; GIK23058-1; GIK23059-1; GIK23060-2; GIK23062-2; GIK23063-1; GIK23065-1; GIK23066-1; GIK23068-1; GIK23071-1; GIK23074-3; GIK23126-1 PS03/126; GIK23138-1 PS03/138; GIK23142-1 PS03/142; GIK23144-1 PS03/144; GIK23227-1 PS05/412; GIK23228-1 PS05/413; GIK23229-1 PS05/414; GIK23230-1 PS05/416; GIK23231-1 PS05/417; GIK23232-1 PS05/418; GIK23233-1 PS05/420; GIK23235-1 PS05/422; GIK23237-1 PS05/425; GIK23238-1 PS05/426; GIK23239-1 PS05/427; GIK23240-1 PS05/428; GIK23241-2 PS05/429; GIK23242-1 PS05/430; GIK23243-1 PS05/431; GIK23243-2 PS05/431; GIK23244-1 PS05/449; GIK23246-2 PS05/451; GIK23247-2 PS05/452; GIK23249-1 PS05/454; GIK23254-3; GIK23258-3; GIK23259-3; GIK23260-2; GIK23261-2; GIK23262-2; GIK23270-2; GIK23277-1; GIK23294-3; GIK23312-2; GIK23323-1; GIK23343-4; GIK23347-4; GIK23348-2; GIK23349-4; GIK23350-3; GIK23351-4; GIK23352-2; GIK23353-2; GIK23354-4; GIK23400-3; GIK23411-5; GIK23414-6; GIK23415-8; GIK23416-5; GIK23418-5; GIK23424-3; GIK23506-1; GIK23507-1; GIK23508-1; GIK23509-1; GIK23512-2; GIK23514-3; GIK23515-4; GIK23516-3; GIK23517-3; GIK23518-2; GIK23519-4; GIK23522-2; GIK23523-3; GIK23524-2; GIK23525-3; GIK23526-3; GIK23527-3; GIK23528-3; GIK23536-1; GIK23537-1; GIK23538-1; GIK23539-1; GIK23540-2; GIK23541-1; GIK23542-1; GIK23543-1; GIK23545-1; GIK23547-4; GIK23549-9; GIK23550-10; GIK23552-8; GIK23554-9; GKG; Global Environmental Change: The Northern North Atlantic; Gravity corer (Kiel type); Greenland Sea; Iceland Sea; KOL; Kong-Oskar-Fjord, East Greenland; M107-1; M17/1; M17/2; M2/1; M2/2; M21/4; M23414; M26/3; M36/3; M7/2; M7/3; M7/4; M7/5; Meteor (1986); MSN; MUC; MULT; MultiCorer; Multiple investigations; Multiple opening/closing net; Northeast Water Polynya; Norway Slope; Norwegian-Greenland Sea; Norwegian Sea; P284-2; P309-1; P317; Piston corer (Kiel type); Polarstern; POS100b; POS119; POS210/2; Poseidon; PS03; PS05; PS07; PS1050-1; PS1060-1; PS1064-1; PS1065-1; PS1227-1; PS1228-1; PS1229-1; PS1230-1; PS1231-1; PS1232-1; PS1233-1; PS1235-1; PS1237-1; PS1238-1; PS1239-1; PS1240-1; PS1241-2; PS1242-1; PS1243-1; PS1243-2; PS1244-1; PS1246-2; PS1247-2; PS1249-1; PS1291-3; PS26/217-1; PS26/258-1; PS26/264-1; PS26/271; PS2613-1; PS2616-7; PS2627-5; PS2638-6; PS2641-5; PS2644-2; PS2645-5; PS2646-2; PS2647-5; PS2656-2; PS26 NEW; PS31; PS31/002; PS31/054; PS31/113; PS31/116; PS31/135; PS31/150; PS31/154; PS31/160; PS31/161; PS31/162; PS31/163; PS31/182; SFB313; SL; van Veen Grab; VGRAB; Voring Plateau
    Type: Dataset
    Format: application/zip, 5 datasets
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  • 3
    Publication Date: 2011-08-03
    Print ISSN: 2572-4517
    Electronic ISSN: 2572-4525
    Topics: Geosciences
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  • 4
  • 5
  • 6
    Publication Date: 2012-04-16
    Description: Background Ecological processes are increasingly being viewed as an important mode of diversification in the marine environment, where the high dispersal potential of pelagic organisms, and a lack of absolute barriers to gene flow may limit the occurrence of allopatric speciation through vicariance. Here we focus on the potential role of ecological partitioning in the diversification of a widely distributed group of marine protists, the planktonic foraminifera. Sampling was conducted in the tropical Arabian Sea, during the southwest (summer) monsoon, when pronounced environmental conditions result in a strong disparity in temperature, salinity and productivity between distinct northern and southern water masses. Results We uncovered extensive genetic diversity within the Arabian Sea planktonic foraminifera, identifying 13 morphospecies, represented by 20 distinct SSU rRNA genetic types. Several morphospecies/genetic types displayed non-random biogeographical distributions, partitioning between the northern and southern water masses, giving a strong indication of independent ecological adaptations. Conclusions We propose sea-surface primary productivity as the main factor driving the geographical segregation of Arabian Sea planktonic foraminifera, during the SW monsoon, with variations in symbiotic associations possibly playing a role in the specific ecological adaptations observed. Our findings suggest that ecological partitioning could be contributing to the high levels of 'cryptic' genetic diversity observed within the planktonic foraminifera, and support the view that ecological processes may play a key role in the diversification of marine pelagic organisms.
    Electronic ISSN: 1471-2148
    Topics: Biology
    Published by BioMed Central
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