Vertical distribution of dissimilatory iron reducing communities in the sediments of Taihu Lake

Yumei Li; Huan Liu; Danjun Ye; Qiaoyun Jiang; Xiangjie Cui; Juan Li; Juli Jiang; Leyong Wang; Xiancai Lu

doi:10.1016/j.scitotenv.2023.164332

Vertical distribution of dissimilatory iron reducing communities in the sediments of Taihu Lake

Sci Total Environ. 2023 Sep 1:889:164332. doi: 10.1016/j.scitotenv.2023.164332. Epub 2023 May 18.

Authors

Yumei Li¹, Huan Liu², Danjun Ye², Qiaoyun Jiang³, Xiangjie Cui², Juan Li², Juli Jiang⁴, Leyong Wang⁴, Xiancai Lu⁵

Affiliations

¹ State Key Laboratory of Analytical Chemistry for Life Science, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, Jiangsu, China; Key Lab of Surficial Geochem, MOE, School of Earth Science and Engineering, Nanjing University, Nanjing 210023, Jiangsu, China.
² Key Lab of Surficial Geochem, MOE, School of Earth Science and Engineering, Nanjing University, Nanjing 210023, Jiangsu, China.
³ School of Life Science, Nanjing University, Nanjing 210023, Jiangsu, China.
⁴ State Key Laboratory of Analytical Chemistry for Life Science, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, Jiangsu, China.
⁵ Key Lab of Surficial Geochem, MOE, School of Earth Science and Engineering, Nanjing University, Nanjing 210023, Jiangsu, China. Electronic address: xcljun@nju.edu.cn.

PMID: 37209744
DOI: 10.1016/j.scitotenv.2023.164332

Abstract

The reduction of Fe(III) coupled with the oxidation of organic matter, primarily stimulated by dissimilatory iron-reducing bacteria (DIRB) under anoxic conditions, is a critical biogeochemical process in lacustrine sediments. Many single strains have been recovered and investigated, however, the changes in the diversity of culturable DIRB communities with sedimentary depth have not been fully revealed. In this study, 41 DIRB strains affiliated to ten genera of phylum Firmicutes, Actinobacteria, and Proteobacteria were isolated from the sediments of Taihu Lake at three depths (0-2 cm, 9-12 cm, and 40-42 cm), referring to distinct nutrient conditions. Fermentative metabolisms were identified in nine genera (except genus Stenotrophomonas). The DIRB community diversity and the microbial iron reduction (MIR) patterns vary in vertical profiles. The community abundance varied with the TOC contents in vertical profiles. The DIRB communities, containing 17 strains of 8 genera, were most diverse in the surface sediments (0-2 cm), where organic matter was most abundant among the three depths. 11 DIRB strains of five genera were identified in the 9-12 cm sediments with the lowest content of organic matter, while 13 strains of seven genera were identified in deep sediments (40-42 cm). Among the isolated strains, phylum Firmicutes dominated the DIRB communities at three depths, while its relative abundance increased with depth. Fe²⁺ ion was recognized as the dominant microbial ferrihydrite-reducing product of DIRB from 0 to 12 cm sediments. Instead, lepidocrocite and magnetite were the main MIR products of DIRB retrieved from 40 to 42 cm. The results indicate that the MIR driven by fermentative DIRB is crucial in lacustrine sediments and that the distribution of nutrients and iron (minerals) likely influences the diversity of DIRB communities in the lacustrine sediments.

Keywords: Culture-dependent method; Dissimilatory iron reducing bacteria; Ferrihydrite; Sediments; Taihu Lake.

MeSH terms

Bacteria / metabolism
Ferric Compounds* / metabolism
Geologic Sediments / chemistry
Iron / analysis
Lakes* / microbiology
Oxidation-Reduction
RNA, Ribosomal, 16S

Substances

Ferric Compounds
Iron
RNA, Ribosomal, 16S