Seasonal Diversity Of Magnetotactic Bacteria In Sediments Of Three Lakes With Different Water Body Types In Wudalianchi

Magnetotactic bacteria(MTB)are a kind of bacteria that can execute directional movement under the action of external magnetic field,and can produce magnetosome.It is mainly distributed in soil,lakes,oceans and other habitats.Morphological diversity and phylogenetic diversity of MTB have always been the focus of research in this field,but MTB research is mainly concentrated in freshwater lakes and oceans,and there are few studies on MTB existing in special environments.In this paper,MTB in the sediments of YC(open),YQH(semi-closed)and YYP(closed)from the volcanic barrier lake in wudalianchi lake on spring,summer,autumn and winter were studied,and the relationship between MTB diversity and environmental factors and MTB function in the metabolic pathway of lakes were studied.The morphological diversity of MTB and magnetosome with arrangement of magnetosome in different seasonal samples were analyzed by transmission electron microscopy(TEM).MTB in the sediment samples of four seasons lakes in three different water bodies were mostly ellipsoidal and spherical in shape,among which fusiform MTB appeared in the summer samples of YYP,and the number of MTB in the summer and autumn samples in three lakes significantly increased and their shapes were plump.In the open water samples,the magnetosomes in MTB presented a dispersed arrangement.In the semi closed water samples,the magnetosomes in MTB were distributed at both ends and arranged in a single chain.In the closed water sample,the magnetosomes in MTB were distributed and arranged in multiple chains.In the three kinds of lakes,the magnetosomes in MTB are mainly free spherical particles.The Proteobacteria and Bacteroidetes species abundance of more than 1% in the YC sediments were found in the spring,summer and winter samples,while,Proteobacteria and Methylophilus were dominant in the autumn.Among them,the species abundance of Proteobacteria was first decreased,then increased and then decreased from spring to winter,and the species abundance of Bacteroidetes was first increased,then decreased and then increased.The species abundance of YQH and YYP in spring,summer and winter samples greater than 1% were also Proteobacteria and Bacteroidetes.There was no significant difference in the abundance of these two dominant species in three seasons of spring,summer and winter.With the change of seasons,the species abundance of these two dominant bacteria generally increased first and then decreased.The autumn sample of YYP,Bacteroidetes and Methylophilus were dominant.In winter,the species abundance of Proteobacteria reached the maximum value,and the difference in species abundance between spring and summer was not significant in YYP.In addition,the physical and chemical factors of the lake sediment samples in different seasons were determined.The environmental factors such as ferrous ions,soluble total iron,sulfide and sulfate ions were greatly affected by seasonal changes.KEGG function projections for MTB in the sample analysis display Amino acid metabolism,Carbohydrate metabolism,Global and the overview maps are the major metabolic pathways,MTB play an important role in the carbon and nitrogen cycle.The morphological and phylogenetic diversities of MTB in the sediments of the three types of volcanic barrier lakes changed with the change of seasons were similar.The type has a small impact on the change of MTB diversity,while the seasonal change has a significantly impact on the change of MTB diversity.Autumn is the most suitable season for MTB growth,with the highest synthesis of magnetosomes and rich species diversity.The phylogenetic diversity of MTB was similar in spring,summer,and winter.Summer is most suitable to study the morphological diversity of MTB,and autumn is most suitable to study the phylogenetic diversity of MTB.This research investigated the diversity of MTB in sediments of volcanic barrier lakes of different water types in four seasons.The morphological diversity and phylogenetic diversity of MTB in the sediment samples of YC,YQH,YYP in wudalianchi lake were revealed in four seasons.The relationship between MTB diversity in the sediments of the three lakes in different seasons and environmental factors was clarified.Understand the main metabolic pathways involved of MTB in lakes and predict its functional role.