Increase in sedimentary organic carbon with a change from hypoxic to oxic conditions

Mukseet Mahmood, Shunsuke Taki, Satoshi Nakai, Takehiko Gotoh, Wataru Nishijima, Akira Umehara, Tomo Aoyagi, Yuya Sato, Tomoyuki Hori, Yoko Katayama, Reka Hajdu-Rahkama, Jaakko A. Puhakka

Research output: Contribution to journalArticleScientificpeer-review

Abstract

In the Seto Inland Sea, Japan, chemical oxygen demand has increased over recent decades, while average dissolved oxygen concentrations in the bottom water have increased. In this study, we investigated responses of organic carbon (OC) in hypoxic sediment to changes of redox conditions using experimental columns containing sediment and overlying water. Surface sediment showed an increase in OC along with the change to an aerobic condition. Microbial community analysis showed a predominance of sulfur-oxidizing bacteria (SOB) such as Sulfurovum sp. in the sediment. This dominance could account for the increased OC. Additionally, the dissolved organic carbon (DOC) concentration in the overlying water increased. Further experiments using sandy sediment showed that biodegradation of Sulfurimonas denitrificans was associated with DOC release. These results show that a change in the sedimentary environment (increase in dissolved oxygen) increased the sedimentary OC and DOC of overlying water by stimulating certain autotrophic bacteria, especially the SOB.

Original languageEnglish
Article number112397
Number of pages10
JournalMARINE POLLUTION BULLETIN
Volume168
DOIs
Publication statusPublished - Jul 2021
Publication typeA1 Journal article-refereed

Keywords

  • Microorganisms
  • Organic carbon
  • Redox condition
  • Sediment
  • Sulfur-oxidizing bacteria

Publication forum classification

  • Publication forum level 1

ASJC Scopus subject areas

  • Oceanography
  • Aquatic Science
  • Pollution

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