Instantaneous benthic response to different organic matter quality: in situ experiments in the Benguela Upwelling System

Fanni Aspetsberger*, Matthias Zabel, Timothy Ferdelman, Ulrich Struck, Andreas Mackensen, Astrid Ahke, Ursula Witte

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)


The benthic community in continental slope and deep-sea sediments of the Benguela Upwelling System was supplied with 13 C-labelled organic matter (OM) of two different qualities using a benthic chamber lander. Freeze-dried cultures of Skeletonema costatum served as 'fresh' OM. 'Altered' OM of the same material had been additionally dialysed to remove low-molecular weight compounds. In order to investigate the benthic response pattern, mineralization of labelled OM, uptake by macrofauna and incorporation into bacteria were followed over 18-36 h. Total oxygen uptake was not affected beyond natural variation by the OM addition. Mineralization dominated the (13)C-labelled phytodetritus processing, constituting 71-95% of the total processed OM. Bacterial incorporation of phytodetrital carbon exceeded macrofaunal uptake at all stations. Stations situated in a major centre of OM deposition showed phytodetritus processing rates on average twice as high as outside the depocentre. Phytodetritus processing was 1.5, 2.5 and 4.3 times higher for fresh than for altered OM at 605, 1019 and 1335 m water depth, respectively. Our observations clearly indicate the importance of OM quality on mineralization rates.

Original languageEnglish
Pages (from-to)342-356
Number of pages15
JournalMarine Biology Research
Issue number5
Publication statusPublished - 20 Nov 2007


  • Benguela Upwelling System
  • benthic chamber lander
  • (13)C labelling
  • deep-sea sediments
  • mineralization
  • OM quality
  • porcupine abyssal-plain
  • Seasonal deposition
  • Continental-margin
  • Atlantic-Ocean
  • sulfate reduction
  • marine-sediments
  • particle fluxes
  • rapid response
  • East Atlantic


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