2024-03-28T23:31:58Zhttps://eprints.lib.hokudai.ac.jp/dspace-oai/requestoai:eprints.lib.hokudai.ac.jp:2115/670462022-11-17T02:08:08Zhdl_2115_20045hdl_2115_139High spatial resolution analysis of the distribution of sulfate reduction and sulfide oxidation in hypoxic sediment in a eutrophic estuaryRathnayake, Rathnayake M. L. DSugahara, ShogoMaki, HideakiKanaya, GenSeike, Yasushi1000080326636Satoh, Hisashiopen access©IWA Publishing 2017. The definitive peer-reviewed and edited version of this article is published in Water Science and Technology 75 2 418-427 2017 10.2166/wst.2016.516 and is available at www.iwapublishing.com.Concentration profilesMicrosensorsParticle compositionPhysicochemical propertiesSediment core sectioningWhite filamentous bacteria500Bottom hypoxia and consequential hydrogen sulfide (H2S) release from sediment in eutrophic estuaries is a major global environmental issue. We investigated dissolved oxygen, pH and H2S concentration profiles with microsensors and by sectioning sediment 2 cores followed by colorimetric analysis. The results of these analyses were then compared with the physicochemical properties of the bottom water and sediment samples to determine their relationships with H2S production in sediment. High organic matter and fine particle composition of the sediment reduced the oxidation-reduction potential, stimulating H2S production. Use of a microsensor enabled measurement of H2S concentration profiles with submillimeter resolution, whereas the conventional sediment-sectioning method gave H2S measurements with a spatial resolution of 10 mm. Furthermore, microsensor measurements revealed H2S consumption occurring at the sediment surface in both the microbial mat and the sediment anoxic layer that were not observed with sectioning. This H2S consumption prevented H2S release into the overlying water. However, the microsensor measurements had the potential to underestimate H2S concentrations. We propose that a combination of several techniques to measure microbial activity and determine its relationships with physicochemical properties of the sediment is essential to understanding the sulfur cycle under hypoxic conditions in eutrophic sediments.IWA Publishing2017-01engjournal articleAMhttp://hdl.handle.net/2115/67046https://doi.org/10.2166/wst.2016.516281126690273-1223Water Science and Technology752418426https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/67046/1/Rathnayake%20No1%202017%20WST.pdfapplication/pdf632.34 KB2017-01