Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Argo-Waste in Cold Region, College of Life Science and Biotechnology, Heilongjiang Bayi Agricultural University, Daqing 163319, PR China.
Institute of Volcano and Spring, Heilongjiang Academy of Science, Wudalianchi 164155, PR China.
Sci Total Environ. 2020 May 20;718:137348. doi: 10.1016/j.scitotenv.2020.137348. Epub 2020 Feb 15.
Magnetotactic bacteria (MTB), the members of sediment microorganisms, play an important role in geochemical iron-cycling and sediment magnetism. This study aimed to investigate the diversity and magnetism contribution of MTB in three volcanic barrier lakes with different waterbody types (open waterbody, YC; semi-enclosed waterbody, WB; and enclosed waterbody, YYP). High-throughput sequencing results showed that MTB affiliated to Alphaproteobacteria, Betaproteobacteria and Nitrospira distributed widely in these lakes. The genera of Magnetococcus (98.10%) and Candidatus Magnetoovum (1.47%) were endemic to YC and WB, respectively. The changes in frequency-dependent susceptibility (χ) values before and after magnetic collection in YC, WB and YYP samples were - 0.28%, 0.05% and - 0.22%, respectively. The magnetic susceptibility was significantly associated with Chao1 (R = 0.637 to 0.763, p < .01) and Shannon index (R = 0.803 to 0.998, p < .01). The room- and low-temperature magnetic characteristics of sediment samples were analyzed by vibrating sample magnetometer (VSM) and radio-frequency superconducting quantum interference device (SQUID). Results indicated that the presence or absence of MTB could lead to the changes in the room- and low-temperature magnetism of volcanic lake sediments, which would extend our knowledge of MTB magnetism contribution to volcanic ecosystems.
趋磁细菌（MTB）作为沉积物微生物的成员，在地球化学铁循环和沉积物磁性中发挥着重要作用。本研究旨在调查三种不同水体类型（开阔水体、YC；半封闭水体、WB；封闭水体、YYP）火山堰塞湖中 MTB 的多样性及其对磁性的贡献。高通量测序结果表明，MTB 隶属于α变形菌门、β变形菌门和硝化螺旋菌门，广泛分布于这些湖泊中。Magnetococcus（98.10%）和 Candidatus Magnetoovum（1.47%）的属分别是 YC 和 WB 的特有属。YC、WB 和 YYP 样品在磁选前后频率相关磁化率（χ）值的变化分别为-0.28%、0.05%和-0.22%。磁化率与 Chao1（R 为 0.637 至 0.763，p<.01）和 Shannon 指数（R 为 0.803 至 0.998，p<.01）显著相关。通过振动样品磁强计（VSM）和射频超导量子干涉装置（SQUID）分析了沉积物样品的室温及低温磁性特征。结果表明，MTB 的存在与否可能导致火山湖沉积物室温及低温磁性的变化，这将扩展我们对 MTB 对火山生态系统磁性贡献的认识。
