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Coccolithophora and geochemistry of sapropel S1 in ODP Hole 160-964B

Authors
Publisher
PANGAEA
Publication Date
Identifiers
DOI: 10.1594/pangaea.811363
Keywords
  • <4 µM
  • >4 µM
  • 160-964B
  • B
  • Bigelowii
  • Ba/Al
  • Barium/Aluminium Ratio
  • Braarudosphaera Bigelowii
  • C
  • Leptoporus
  • C
  • Pelagicus Ssp
  • Brarudii
  • C
  • Pelagicus Ssp
  • Pelagicus
  • Calcidiscus Leptoporus
  • Calciosolenia Spp
  • Ceratolithus Spp
  • Chromium/Aluminium Ratio
  • Co/Al
  • Cobalt/Aluminium Ratio
  • Coccolithus Pelagicus Ssp
  • Brarudii
  • Coccolithus Pelagicus Ssp
  • Pelagicus
  • Copper/Aluminium Ratio
  • Cr/Al
  • Cu/Al
  • D
  • Tubifera
  • Discosphaera Tubifera
  • Drilling
  • E
  • Huxleyi
  • Eastern Basin
  • Emiliania Huxleyi
  • F
  • Profunda
  • Fields
  • Florisphaera Profunda
  • G
  • Caribbeanica
  • G
  • Muellerae
  • G
  • Oceanica
  • Gephyrocapsa Caribbeanica
  • Gephyrocapsa Muellerae
  • Gephyrocapsa Oceanica
  • Gephyrocapsa Spp
  • Small
  • Gephyrocapsa Spp
  • Small
  • Gladiolithus Spp
  • H
  • Carteri
  • H
  • Pavimentum
  • H
  • Wallichii
  • Helicosphaera Carteri
  • Helicosphaera Pavimentum
  • Helicosphaera Spp
  • Helicosphaera Wallichii
  • Holococcolithus Spp
  • Icp-Aes
  • Inductively Coupled Plasma - Atomic Emission Spectroscopy
  • Joides Resolution
  • Label
  • Leg160
  • Lpz
  • Manganese/Aluminium Ratio
  • Mediterranean Sea Acidification In A Changing Climate
  • Medsea
  • Misc
  • Miscellaneous
  • Mn/Al
  • Mo/Al
  • Molybdenum/Aluminium Ratio
  • Nannofossil Counts
  • Filtering Preparation
  • Nannofossils
  • Nannofossils
  • Lower Photic Zone Group
  • Nannofossils
  • Upper Photic Zone Group
  • Nannofossils Indeterminata
  • Nannos
  • Nannos Indet
  • Ni/Al
  • Nickel/Aluminium Ratio
  • Ocean Drilling Program
  • Odp
  • Odp Sample Designation
  • Oolithotus Spp
  • Others
  • Placoliths
  • Placoliths
  • Small
  • Placoliths Small
  • Pleurochrysis Spp
  • Pontosphaera Spp
  • Rhabdosphaera Spp
  • S
  • Histrica
  • S
  • Pulchra
  • Sample Code/Label
  • Sample Mass
  • Samp M
  • Smear Slide Analysis
  • Syracopshaera Histrica
  • Syracosphaera Pulchra
  • T
  • Heimii
  • Thoracosphaera Heimii
  • Total
  • Total 1
  • Total 2
  • Umbellosphaera Spp
  • Umbilicosphaera Spp
  • Upz
  • V/Al
  • Vanadium/Aluminium Ratio
  • Zinc/Aluminium Ratio
  • Zn/Al
Disciplines
  • Biology
  • Chemistry
  • Earth Science
  • Geography

Abstract

The cyclic development of anoxic conditions in the eastern Mediterranean deep sea waters is one of the most fascinating research topics in paleoceanographic studies. In combination with bottom water stagnation, enhanced primary production is a common explanation for the deposition of organic-rich layers (sapropels). This is supported by extensive evidence from both geochemical and micropaleontological studies. The correspondence of recent sapropel layers with peaks of the lower photic zone coccolithophore species Florisphaera profunda has been interpreted as a proxy for the development of a deep chlorophyll maximum (DCM), due to the pycnocline/nutricline shallowing into the lower part of the photic zone. We present millennial-scale data for coccolithophore assemblages from sediments across the most recent sapropel (S1), in the ODP Hole 964B drilled in the Ionian Sea. Relative and absolute abundances of taxa are compared with selected elemental composition of the bulk sediments. The Mn/Al and Ba/Al profiles are used to determine the original thickness of the S1 interval, and show that the upper part of S1 was affected by post-depositional oxidation of organic matter. The Nannofossil Accumulation Rate, defined by the number of coccoliths/cm**2/kyr, suggests that there is no evidence of increased productivity within most of the sapropel layer. In fact, coccolithophore production was at its minimum in the lower part. Minimum coccolith concentrations are reached despite the increase in F. profunda in both relative and absolute abundance. We suggest that the DCM deduced from the increased productivity of this species did not significantly contribute to the putative overall increased primary productivity during the deposition of most of the sapropel layer. Within the upper oxidized part of S1, coccolith accumulation was at least five times higher than in the lower part. This period of high coccolith productivity finds a counterpart in the increase of the Ba/Al ratio. The total concentration of coccoliths is again controlled by the amount of E. huxleyi, but it is also supported by concomitant increases in all the other groups, suggesting that coccolithophore productivity increased throughout the year and through the total vertical extent of the photic zone. At site 964, this is apparently the only moment when coccolithophores contributed substantially to the increased primary productivity generally assumed for the S1 layer.

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