Postglacial paleoceanography of the western Barents Sea : Implications for alkenone-based sea surface temperatures and primary productivity
Łącka, Magdalena (Polish Academy of Sciences. Institute of Oceanology (Poland))
Cao, Min (Universitat Autònoma de Barcelona. Institut de Ciència i Tecnologia Ambientals)
Rosell Melé, Antoni (Universitat Autònoma de Barcelona. Institut de Ciència i Tecnologia Ambientals)
Pawłowska, Joanna (Polish Academy of Sciences. Institute of Oceanology (Poland))
Kucharska, Małgorzata (Polish Academy of Sciences. Institute of Oceanology (Poland))
Forwick, Matthias (UiT The Arctic University of Norway in Tromsø. Department of Geosciences (Norway))
Zajączkowski, Marek (Polish Academy of Sciences. Institute of Oceanology (Poland))

Date:	2019
Abstract:	The increasing influence of Atlantic Water (AW) in the Barents Sea, a process known as "Atlantification", is gradually decreasing sea ice cover in the region. Ongoing global climate warming is likely to be one of its drivers, but to further understand the role of natural variability and the biogeochemical impacts of the inflow of AW into the western Barents Sea, we reconstructed sea surface temperatures (SSTs) and primary productivity in Storfjordrenna, a climatically sensitive area south of Spitsbergen, between approximately 13,950 cal yr BP and 1300 cal yr BP. The alkenone U proxy has been applied to reconstruct SSTs, and the alkenone accumulation rate in marine sediments has been used to infer changes in primary productivity. Our data show that the SST increase was concomitant with the progressive loss of sea ice cover and an increase in primary productivity in the western Barents Sea. We interpret these changes as reflecting the increasing influence of AW in the area as the ice sheets retreated in Svalbard. The transition from the Arctic to the Atlantic domain first occurred after 11,500 cal yr BP, as the Arctic Front moved eastward of the study site but with considerable variability in surface ocean conditions. High SSTs at approximately 6400 cal yr BP may have led to limited winter surface cooling, likely inhibiting convective mixing and the return of nutrients to the euphotic zone and/or enhanced organic matter consumption by zooplankton due to an earlier light signal in the ice-free Storfjordrenna. During the late Holocene (3600-1300 cal yr BP), low insolation facilitated sea ice formation and thus brine production. The former may have launched convective water mixing and increased nutrient resupply to the sea surface, consequently enhancing primary productivity in Storfjordrenna. We propose that, on the basis of the paleoceanographic evidence, the modern increasing inflow of warm AW and the disappearance of pack ice on the Eurasian continental shelf are likely to weaken convective water mixing and decrease primary production in the region.
Grants:	Ministerio de Economía y Competitividad MDM2015-0552
Note:	Unidad de excelencia María de Maeztu MdM-2015-0552
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, i la comunicació pública de l'obra, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original. No es permet la creació d'obres derivades.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Alkenones ; Stratification ; Holocene ; Sea ice decrease ; Global warming ; North Atlantic Current ; Arctic
Published in:	Quaternary Science Reviews, Vol. 224 (November 2019) , art. 105973, ISSN 0277-3791

DOI: 10.1016/j.quascirev.2019.105973

14 p, 2.5 MB

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Research literature > UAB research groups literature > Research Centres and Groups (research output) > Experimental sciences > Institut de Ciència i Tecnologia Ambientals (ICTA)
Articles > Research articles
Articles > Published articles