Biogeochemical conditions in sediments enriched by organic matter from net-pen fish farms in the Bolinao area, Philippines

Marianne Holmer*, Carlos Duarte, Anna Heilskov, Birgit Olesen, Jorge Terrados

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

83 Scopus citations


Sedimentation and sediment metabolism was measured at eight active milkfish fish pens and at one abandoned site in the Bolinao area, Philippines in order to examine the interactions between sediment and water in this shallow coastal zone. The rates of sedimentation were high in the area due to siltation, but the activities in the fish pens also contributed to enhanced sedimentation as indicated by the difference between the abandoned and active sites. The sediment metabolism appeared to decrease with increasing rates of sedimentation indicating that the microbial activity reached a saturation level in the fish pen sediments. Anaerobic processes dominated the organic matter decomposition, and sulfate reduction rates are among the highest measured in fish farm sediments. The rates decreased with increasing organic loading despite high concentrations of sulfate (>10 mM) at all sites. Presence of methane bubbles in the sediments suggests that sulfate reduction and methanogenesis were coexisting. The sediment metabolism was significantly reduced at the abandoned site indicating that the stimulation of microbial activities is due to active fish production. The anaerobic activity remained high at the abandoned site indicating that the sediment biogeochemical conditions remain affected long time after fish production has ceased.

Original languageEnglish (US)
Pages (from-to)1470-1479
Number of pages10
JournalMarine Pollution Bulletin
Issue number11
StatePublished - Jan 1 2003


  • Fish pen
  • Organic enrichment
  • Sediment metabolism
  • Sulfate reduction rates

ASJC Scopus subject areas

  • Oceanography
  • Aquatic Science
  • Pollution


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