Controlling organic carbon increase in oxygenated marine sediment by using decarburization slag.

Autor: Mahmood M; Department of Oceanography and Coastal Sciences, Louisiana State University, Louisiana, USA., Kato N; Graduate School of Advanced Science and Engineering, Hiroshima University, Hiroshima, Japan., Nakai S; Graduate School of Advanced Science and Engineering, Hiroshima University, Hiroshima, Japan. Electronic address: sn4247621@hiroshima-u.ac.jp., Gotoh T; Graduate School of Advanced Science and Engineering, Hiroshima University, Hiroshima, Japan., Nishijima W; Environmental Research and Management Center, Hiroshima University, Hiroshima, Japan., Umehara A; Environmental Research and Management Center, Hiroshima University, Hiroshima, Japan.
Jazyk: angličtina
Zdroj: Journal of environmental management [J Environ Manage] 2024 May; Vol. 358, pp. 120820. Date of Electronic Publication: 2024 Apr 10.
DOI: 10.1016/j.jenvman.2024.120820
Abstrakt: The chemical oxygen demand (COD) in the Seto Inland Sea, Japan has increased in the recent decades due to the increase of bottom dissolved oxygen (DO) concentration which stimulated several autotrophic microorganisms, specially sulfur oxidizing bacteria (SOB). This increased SOB activity due to the oxygenation of the bottom sediment synthesized new organic matter (OM) which contributed dissolved organic carbon to the overlying seawater. This phenomenon further led to hypoxia in some subareas in the Seto Inland Sea. Higher pH or alkaline environment has been found to be an unfavorable condition for SOB. In this research, we used decarburization slag to elevate the pH of sediment to control the SOB activity and consequently reduce OM production in the sediment. Ignition loss of the surface sediment increased from 5.14% 6.38% after 21 days of incubation with aeration; whereas the sediment showed the less ignition loss of 5.71% after 21 days when the slag was incubated in the same experimental setup. Microbial community analysis showed less SOB activity in the slag added aerated sediment which accounts for the controlled increase of OM in the sediment. An additional experiment was conducted with magnesium oxide to confirm whether elevated pH can control the OM increase in sediment due to rising DO. All these results showed that decarburization slag can elevate the pH of the sediment to a certain level which can control the SOB activity followed by controlled increase of OM in the sediment. The findings may be beneficial to control accumulation of sedimentary OM which can act as a source of organic carbon in the overlying seawater.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2024 Elsevier Ltd. All rights reserved.)
Databáze: MEDLINE
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