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The interplay between the surface and bottom water environment within the Benguela Upwelling System over the last 70 ka

Mckay, Claire LU ; Filipsson, Helena LU ; Romero, O. E.; Stuut, J. B W and Björck, Svante LU (2016) In Paleoceanography 31(2). p.266-285
Abstract

The Benguela Upwelling System (BUS), located between 30 and 20°S, is one of the fundamental high-productivity systems of the world ocean. The BUS has previously been studied in terms of primary productivity and ecology over glacial-interglacial timescales; however, the response and coupling with the benthic environment have received little attention. Here, for the first time, we present a high-resolution reconstruction of the BUS highlighting the link between surface and benthic productivity and their response to climatic and oceanographic changes over the last 70 ka. The study is based on benthic foraminiferal faunal analysis together with analyses of diatom assemblages, grain size of the terrigenous fraction, and stable O and C... (More)

The Benguela Upwelling System (BUS), located between 30 and 20°S, is one of the fundamental high-productivity systems of the world ocean. The BUS has previously been studied in terms of primary productivity and ecology over glacial-interglacial timescales; however, the response and coupling with the benthic environment have received little attention. Here, for the first time, we present a high-resolution reconstruction of the BUS highlighting the link between surface and benthic productivity and their response to climatic and oceanographic changes over the last 70 ka. The study is based on benthic foraminiferal faunal analysis together with analyses of diatom assemblages, grain size of the terrigenous fraction, and stable O and C isotopic and bulk biogenic components of core GeoB3606-1. We reveal significant shifts in benthic foraminiferal assemblage composition. Tight coupling existed between the surface and bottom water environment especially throughout marine isotope stages 4 and 3 (MIS4 and MIS3). Due to the high export production, the site has essentially experienced continuous low oxygen conditions; however, there are time periods where the hypoxic conditions were even more notable. Two of these severe hypoxic periods were during parts of MIS4 and MIS3 where we find an inverse relationship between diatom and benthic foraminifera accumulation, meaning that during times of extremely high phytodetritus export we note strongly suppressed benthic productivity. We also stress the importance of food source for the benthos throughout the record. Shifts in export productivity are attributed not only to upwelling intensity and filament front position, but also, regional-global climatic and oceanographic changes had significant impact on the BUS dynamics.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Benguela, benthic response, productivity, Quaternary, upwelling
in
Paleoceanography
volume
31
issue
2
pages
20 pages
publisher
American Geophysical Union
external identifiers
  • scopus:84975758199
  • wos:000372727100004
ISSN
0883-8305
DOI
10.1002/2015PA002792
language
English
LU publication?
yes
id
aa96f928-547d-4d02-a91b-345d64fabbc7
date added to LUP
2016-10-05 15:34:26
date last changed
2017-02-13 15:16:56
@article{aa96f928-547d-4d02-a91b-345d64fabbc7,
  abstract     = {<p>The Benguela Upwelling System (BUS), located between 30 and 20°S, is one of the fundamental high-productivity systems of the world ocean. The BUS has previously been studied in terms of primary productivity and ecology over glacial-interglacial timescales; however, the response and coupling with the benthic environment have received little attention. Here, for the first time, we present a high-resolution reconstruction of the BUS highlighting the link between surface and benthic productivity and their response to climatic and oceanographic changes over the last 70 ka. The study is based on benthic foraminiferal faunal analysis together with analyses of diatom assemblages, grain size of the terrigenous fraction, and stable O and C isotopic and bulk biogenic components of core GeoB3606-1. We reveal significant shifts in benthic foraminiferal assemblage composition. Tight coupling existed between the surface and bottom water environment especially throughout marine isotope stages 4 and 3 (MIS4 and MIS3). Due to the high export production, the site has essentially experienced continuous low oxygen conditions; however, there are time periods where the hypoxic conditions were even more notable. Two of these severe hypoxic periods were during parts of MIS4 and MIS3 where we find an inverse relationship between diatom and benthic foraminifera accumulation, meaning that during times of extremely high phytodetritus export we note strongly suppressed benthic productivity. We also stress the importance of food source for the benthos throughout the record. Shifts in export productivity are attributed not only to upwelling intensity and filament front position, but also, regional-global climatic and oceanographic changes had significant impact on the BUS dynamics.</p>},
  author       = {Mckay, Claire and Filipsson, Helena and Romero, O. E. and Stuut, J. B W and Björck, Svante},
  issn         = {0883-8305},
  keyword      = {Benguela,benthic response,productivity,Quaternary,upwelling},
  language     = {eng},
  month        = {02},
  number       = {2},
  pages        = {266--285},
  publisher    = {American Geophysical Union},
  series       = {Paleoceanography},
  title        = {The interplay between the surface and bottom water environment within the Benguela Upwelling System over the last 70 ka},
  url          = {http://dx.doi.org/10.1002/2015PA002792},
  volume       = {31},
  year         = {2016},
}