Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
The POC/Th-234 ratio of settling particles isolated using split flow-thin cell fractionation (SPLITT)
Responsible organisation
2006 (English)In: Marine Chemistry, ISSN 0304-4203, E-ISSN 1872-7581, Vol. 100, no 3-4, 314-322 p.Article in journal (Refereed) Published
Abstract [en]

The common assumption that the ratio between particulate organic carbon (POC) and particulate Th-234 obtained from shallow sediment traps and filterable particles are representative of the ratio in the total particle settling flux should be treated with caution in view of well-known biases associated with tethered shallow sediment traps and the decoupling between size and settling velocity of many natural particle regimes. To make progress toward reliably constraining the POC/Th-234 ratio on truly settling particles, we have tested here a settling collection technique designed to remove any hydrodynamic bias; split flow-thin cell fractionation (SPLITT). These first results from a North Sea fjord and an open Baltic Sea time-series station indicates that the POC/Th-234 ratio on the more complete particle-settling spectrum, isolated with SPLITT, was higher than the POC/Th-234 ratio obtained simultaneously from tethered shallow sediment traps in seven out of seven parallel deployments with an average factor of 210%. The POC/Th-234 ratio from the SPLITT was either in the same range or higher than that obtained on filtered “bull’ particles. To explain this novel data we hypothesize that the slowest settling fraction is organic-matter rich and does not strongly complex Th-234 (i.e., high POC/Th-234). We suggest that this ultra-slow sinking fraction is better collected by SPLITT than with tethered sediment traps because of minimized hydrodynamic bias. This was tested using the ratio of POC/Al as a tracer of detrital mineral-ballast influenced settling velocity. The higher POC/Al ratios in SPLITT samples relative to in traps is consistent with the hypothesis that SPLITT is better suited for collecting also the slow-settling component of sinking particles. This important slow-settling component appears to here consist primarily of non-APS/TEP components of plankton exudates or other less-strongly Th-234-complexing organic matter. Further applications of the SPLITT technique are likely to return increasingly new insights on the composition (including “truly settling” POC/Th-234) of the total spectrum of particles settling out of the upper ocean. (c) 2005 Elsevier B.V. All rights reserved.

Place, publisher, year, edition, pages
2006. Vol. 100, no 3-4, 314-322 p.
Keyword [en]
ocean export; organic carbon; methods; thorium-234
National Category
Natural Sciences
Research subject
SWEDARCTIC 2001, Arctic Ocean 2001
Identifiers
URN: urn:nbn:se:polar:diva-3194DOI: 10.1016/j.marchem.2005.10.018OAI: oai:DiVA.org:polar-3194DiVA: diva2:1050203
Note

Workshop on the Future Applications of 234 Th in Aquatic Ecosystems (FATE), Woods Hole, MA, AUG, 2004

Available from: 2016-11-28 Created: 2016-11-21 Last updated: 2016-11-28

Open Access in DiVA

No full text

Other links

Publisher's full text
In the same journal
Marine Chemistry
Natural Sciences

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 11 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf