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Pelagic-benthic coupling within an upwelling system of the subtropical northeast Atlantic over the last 35 ka BP

McKay, Claire LU ; Filipsson, Helena LU ; Romero, O. E.; Stuut, J. -B. W. and Donner, B. (2014) In Quaternary Science Reviews 106. p.299-315
Abstract
We present a high resolution, multiproxy study of the relationship between pelagic and benthic environments of a coastal upwelling system in the subtropical NE Atlantic Ocean. Marine sediments corresponding to late MIS3 to the Holocene in the radiocarbon dated core GeoB7926, retrieved off Mauritania (21 degrees N) were analysed to reconstruct productivity in surface waters and its linkage to deep waters during the last 35 ka BP. High latitude cold events and changes in atmospheric and oceanographic dynamics influenced upwelling intensity over this time period. Subsequently, this caused changes in primary productivity off this low-latitude coastal upwelling locality. The benthic foraminiferal fauna displays four main community shifts... (More)
We present a high resolution, multiproxy study of the relationship between pelagic and benthic environments of a coastal upwelling system in the subtropical NE Atlantic Ocean. Marine sediments corresponding to late MIS3 to the Holocene in the radiocarbon dated core GeoB7926, retrieved off Mauritania (21 degrees N) were analysed to reconstruct productivity in surface waters and its linkage to deep waters during the last 35 ka BP. High latitude cold events and changes in atmospheric and oceanographic dynamics influenced upwelling intensity over this time period. Subsequently, this caused changes in primary productivity off this low-latitude coastal upwelling locality. The benthic foraminiferal fauna displays four main community shifts corresponding to fundamental climatic events, first of all during late MIS3 (35 28 ka BP), secondly from 28 to 19 ka BP (including Heinrich event 2 and the LGM), thirdly within Heinrich event 1, the Bolling Allerod and the Younger Diyas (18-11.5 ka BP) and finally during the Holocene (11.5-0 ka BP). In particular, strong pelagic benthic coupling is apparent in MIS 3, as demonstrated by increased primary productivity, indicated by moderate DAR and the dominance of benthic foraminiferal species which prefer fresh phytodetritus. A decline in upwelling intensity and nutrient availability follows, which resulted in a proportionately larger amount of older, degraded matter, provoking a shift in the benthic foraminifera fauna composition. This rapid response of the benthic environment continues with a progressive increase in upwelling intensity due to sea level and oceanographic changes and according high surface production during the LGM. During Heinrich event 1 and the Younger Dryas, extreme levels of primary production actually hindered benthic environment through the development of low oxygen conditions. After this period, a final change in benthic foraminiferal community composition occurs which indicates a return to more oxygenated conditions during the Holocene. (C) 2014 Elsevier Ltd. All rights reserved. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Pelagic-benthic, Upwelling, Palaeoproductivity, Benthic foraminifera, Subtropical NE Atlantic
in
Quaternary Science Reviews
volume
106
pages
299 - 315
publisher
Elsevier
external identifiers
  • wos:000348010900019
  • scopus:84900685455
ISSN
0277-3791
DOI
10.1016/j.quascirev.2014.04.027
language
English
LU publication?
yes
id
825e9362-199b-4d9e-b5b8-b09c48f79641 (old id 5070079)
date added to LUP
2015-02-25 16:06:07
date last changed
2017-01-01 03:42:35
@article{825e9362-199b-4d9e-b5b8-b09c48f79641,
  abstract     = {We present a high resolution, multiproxy study of the relationship between pelagic and benthic environments of a coastal upwelling system in the subtropical NE Atlantic Ocean. Marine sediments corresponding to late MIS3 to the Holocene in the radiocarbon dated core GeoB7926, retrieved off Mauritania (21 degrees N) were analysed to reconstruct productivity in surface waters and its linkage to deep waters during the last 35 ka BP. High latitude cold events and changes in atmospheric and oceanographic dynamics influenced upwelling intensity over this time period. Subsequently, this caused changes in primary productivity off this low-latitude coastal upwelling locality. The benthic foraminiferal fauna displays four main community shifts corresponding to fundamental climatic events, first of all during late MIS3 (35 28 ka BP), secondly from 28 to 19 ka BP (including Heinrich event 2 and the LGM), thirdly within Heinrich event 1, the Bolling Allerod and the Younger Diyas (18-11.5 ka BP) and finally during the Holocene (11.5-0 ka BP). In particular, strong pelagic benthic coupling is apparent in MIS 3, as demonstrated by increased primary productivity, indicated by moderate DAR and the dominance of benthic foraminiferal species which prefer fresh phytodetritus. A decline in upwelling intensity and nutrient availability follows, which resulted in a proportionately larger amount of older, degraded matter, provoking a shift in the benthic foraminifera fauna composition. This rapid response of the benthic environment continues with a progressive increase in upwelling intensity due to sea level and oceanographic changes and according high surface production during the LGM. During Heinrich event 1 and the Younger Dryas, extreme levels of primary production actually hindered benthic environment through the development of low oxygen conditions. After this period, a final change in benthic foraminiferal community composition occurs which indicates a return to more oxygenated conditions during the Holocene. (C) 2014 Elsevier Ltd. All rights reserved.},
  author       = {McKay, Claire and Filipsson, Helena and Romero, O. E. and Stuut, J. -B. W. and Donner, B.},
  issn         = {0277-3791},
  keyword      = {Pelagic-benthic,Upwelling,Palaeoproductivity,Benthic foraminifera,Subtropical NE Atlantic},
  language     = {eng},
  pages        = {299--315},
  publisher    = {Elsevier},
  series       = {Quaternary Science Reviews},
  title        = {Pelagic-benthic coupling within an upwelling system of the subtropical northeast Atlantic over the last 35 ka BP},
  url          = {http://dx.doi.org/10.1016/j.quascirev.2014.04.027},
  volume       = {106},
  year         = {2014},
}