研究生学术报告预告登记(开题、中期、答辩)

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报告人: 李建洋
学号: 1017214040
学院: 环境科学与工程学院
报告类型: 其他学术报告
日期: 24 November 2022
时间: 2:55 PM
地点: 厦门亚洲海湾大酒店
导师: 汪光义
题目: 深海微生物介导的天然沉降有机物原位矿化研究
内容提要:

Transfer of animal and plant detritus of both terrestrial and marine origins to the deep sea occurs on a global scale. Microorganisms play an important role in mineralizing them therein, but these are yet to be identified in situ. To observe key bacteria involved, we conducted long-term in situ incubation and found that members of the family Marinifilaceae (MF) occurred as some of the most predominant bacteria thriving on the new inputs of plant and animal biomasses in the deep sea in both marginal and oceanic areas, as well as in whale falls and wood falls. At least 9 subgroups were revealed based on 16S rRNA gene phylogenetic tree, and they were widely distributed in oceans globally but predominant in organic-matter-rich environments, with an average relative abundance of 8.3%. A total of 11 MAGs belonging to MF were retrieved from metagenomic data and diverged into four subgroups (MF-1, MF-2, MF-3, and MF-4) in the phylogenomic tree. Based on metagenomic and metatranscriptomic analyses, we described the metabolic features and in situ metabolizing activities of different subgroups. The MF-2 subgroup, which dominates plant detritus-enriched cultures, specializes in polysaccharide degradation and lignin oxidation and has high transcriptional activities of related genes in situ. Intriguingly, members of this subgroup encode a nitrogen fixation pathway to compensate for the shortage of nitrogen sources inside the plant detritus. In contrast, other subgroups dominating the animal tissue-supported microbiomes are distinguished from MF-2 with regard to carbon and nitrogen metabolism and exhibit high transcriptional activity for proteolysis in situ. Despite these metabolic divergences of MF lineages, they show high in situ transcriptional activities for organic fermentation and anaerobic respiration (reductions of metal and/or dimethyl sulfoxide). These results highlight the role of previously unrecognized Marinifilaceae bacteria in organic matter mineralization in marine environments by coupling carbon and nitrogen cycling with metal and sulfur.

Keywords: Deep sea, Marinifilaceae, biodiversity, organic matter mineralization, lignin oxidation, nitrogen fixation

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登记人: 李建洋
登记时间: Wednesday, 26 April 2023, 1:59 PM