scholarly journals Biogeographical distribution of microbial communities along the Rajang River–South China Sea continuum

2019 ◽  
Vol 16 (21) ◽  
pp. 4243-4260
Author(s):  
Edwin Sien Aun Sia ◽  
Zhuoyi Zhu ◽  
Jing Zhang ◽  
Wee Cheah ◽  
Shan Jiang ◽  
...  

Abstract. The Rajang River is the main drainage system for central Sarawak in Malaysian Borneo and passes through peat domes through which peat-rich material is being fed into the system and eventually into the southern South China Sea. Microbial communities found within peat-rich systems are important biogeochemical cyclers in terms of methane and carbon dioxide sequestration. To address the critical lack of knowledge about microbial communities in tropical (peat-draining) rivers, this study represents the first seasonal assessment targeted at establishing a foundational understanding of the microbial communities of the Rajang River–South China Sea continuum. This was carried out utilising 16S rRNA gene amplicon sequencing via Illumina MiSeq in size-fractionated samples (0.2 and 3.0 µm GF/C filter membranes) covering different biogeographical features and sources from headwaters to coastal waters. The microbial communities found along the Rajang River exhibited taxa common to rivers (i.e. predominance of β-Proteobacteria) while estuarine and marine regions exhibited taxa that were common to the aforementioned regions as well (i.e. predominance of α− and γ-Proteobacteria). This is in agreement with studies from other rivers which observed similar changes along salinity gradients. In terms of particulate versus free-living bacteria, nonmetric multi-dimensional scaling (NMDS) results showed similarly distributed microbial communities with varying separation between seasons. Distinct patterns were observed based on linear models as a result of the changes in salinity along with variation of other biogeochemical parameters. Alpha diversity indices indicated that microbial communities were higher in diversity upstream compared to the marine and estuarine regions, whereas anthropogenic perturbations led to increased richness but less diversity. Despite the observed changes in bacterial community composition and diversity that occur along the continuum of the Rajang River to the sea, the PICRUSt predictions showed minor variations. The results provide essential context for future studies such as further analyses on the ecosystem response to anthropogenic land-use practices and probable development of biomarkers to improve the monitoring of water quality in this region.

2019 ◽  
Author(s):  
Edwin Sien Aun Sia ◽  
Zhuoyi Zhu ◽  
Jing Zhang ◽  
Wee Cheah ◽  
Jiang Shan ◽  
...  

Abstract. Microbial community composition and diversity in freshwater habitats, especially in lotic environments, are much less studied compared to marine and soil communities. The Rajang River is the main drainage system for central Sarawak in Malaysian Borneo and passes through peat domes whereby peat-rich material is being fed into the system and eventually into the southern South China Sea. Microbial communities found within peat-rich systems are important biogeochemical cyclers in terms of methane and carbon dioxide sequestration. To address the critical lack of knowledge about microbial communities in tropical (peat-draining) rivers, this study represents the first seasonal assessment targeted at establishing a foundational understanding of the microbial communities of the Rajang River-South China Sea continuum. This was carried out utilizing 16S rRNA gene amplicon sequencing via Illumina MiSeq in size-fractionated samples (0.2 and 3.0 μm GF/C filter membranes) covering different biogeographical features/sources from headwaters to coastal waters. The microbial communities found along the Rajang river exhibited taxa common to rivers (i.e. the predominance of β-Proteobacteria) while estuarine and marine regions exhibited taxa that were common to the aforementioned regions as well (i.e. predominance of α- and γ-Proteobacteria). This is in agreement with studies from other rivers which observed similar changes along the salinity gradients. In terms of particulate versus free-living bacteria, nonmetric multi-dimensional scaling (NMDS) results showed similarly distributed microbial communities with varying separation between seasons. Distinct patterns were observed based on linear models as a result of the changes in salinity along with variation of other biogeochemical parameters. Alpha diversity indices indicated that microbial communities were higher in diversity upstream compared to the marine and estuarine regions whereas anthropogenic perturbations led to increased richness but less diversity. Despite the observed changes in bacterial community composition and diversity that occur along the Rajang River to sea continuum, the PICRUST predictions showed minor variations. The results provide essential context for future studies such as further analyses on the ecosystem health in response to anthropogenic land-use practices and probable development of biomarkers to improve the monitoring of water quality in this region.


2007 ◽  
Vol 57 (2) ◽  
pp. 219-222 ◽  
Author(s):  
Jiao-Yan Ying ◽  
Zhi-Pei Liu ◽  
Bao-Jun Wang ◽  
Xin Dai ◽  
Su-Sheng Yang ◽  
...  

A novel marine bacterial strain, HY1T, was isolated from sediment of the South China Sea. The strain was aerobic and heterotrophic and formed saffron yellow-pigmented colonies on marine agar 2216. Cells were non-motile, Gram-negative rods, frequently occurring in chains. blastn searches revealed that the 16S rRNA gene sequence of strain HY1T showed high similarity with those of members of the genera Gillisia (91.7–93.8 %) and Salegentibacter (92.6–93.5 %). Phylogenetic analysis based on 16S rRNA gene sequences showed that the strain clustered with members of both Salegentibacter and Gillisia and phylogenetic trees constructed using three different methods (neighbour-joining, maximum-parsimony and minimum-evolution) indicated that strain HY1T clustered more frequently with members of the genus Salegentibacter. The DNA G+C content of strain HY1T was 44.4 mol% and its major cellular fatty acids (⩾5 % of the total fatty acids) were iso-15 : 1 (5.0 %), iso-15 : 0 (6.8 %), anteiso-15 : 0 (6.4 %), 15 : 0 (10.4 %), iso-16 : 0 (13.5 %), summed feature 3 (comprising iso-15 : 0 2-OH and/or 16 : 1ω7c; 6.3 %), iso-17 : 0 3-OH (5.2 %) and 17 : 0 2-OH (5.0 %). Cells contained menaquinone 6. Based on the phylogenetic and phenotypic analyses, strain HY1T should be classified as representing a novel species within the genus Salegentibacter, for which the name Salegentibacter catena sp. nov. is proposed. The type strain is HY1T (=CGMCC 1.6101T=JCM 14015T). Based on this study and on previously described Salegentibacter species, an emended description of the genus Salegentibacter is given.


2016 ◽  
Vol 12 (10) ◽  
pp. 1101-1108
Author(s):  
Zhuhong Liu ◽  
Chang Chen ◽  
Lei Gao ◽  
Yuyang Zhang ◽  
Jingjing Pei ◽  
...  

2015 ◽  
Vol 65 (Pt_2) ◽  
pp. 452-456 ◽  
Author(s):  
Yongle Xu ◽  
Rui Zhang ◽  
Qipei Li ◽  
Keshao Liu ◽  
Nianzhi Jiao

A novel, aerobic, heterotrophic, orange-pigmented, Gram-staining-negative, rod-shaped, gliding bacterial strain, designated JLT2000T, was isolated from surface water of the South China Sea. The strain was oxidase- and catalase-positive. The major cellular fatty acids of strain JLT2000 T were C12 : 0, iso-C15 : 1 G, iso-C15 : 0, iso-C17 : 0 3-OH, summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c), C16 : 0 and C18 : 0. MK-7 was the major respiratory quinone and the major polar lipids were phosphatidylcholine and phosphatidylethanolamine. The genomic DNA G+C content of strain JLT2000T was 37.9 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain JLT2000T formed a branch within the genus Marivirga , but was clearly separated from the two established species of this genus, Marivirga tractuosa and Marivirga sericea . The 16S rRNA gene sequence similarity of strain JLT2000T with the type strains of these two species was 95.8 % and 96.1 %, respectively. Strain JLT2000T had a shorter cell length and wider growth range in different temperatures and salinities than those of Marivirga tractuosa NBRC 15989T and Marivirga sericea NBRC 15983T. In addition, strain JLT2000T could utilize more carbon sources and hydrolyse more polymers than Marivirga tractuosa NBRC 15989T and Marivirga sericea NBRC 15983T. Based on this polyphasic analysis, strain JLT2000T represents a novel species of the genus Marivirga , for which the name Marivirga lumbricoides sp. nov. is proposed. The type strain is JLT2000T ( = JCM 18012T = CGMCC 1.10832T).


2010 ◽  
Vol 60 (9) ◽  
pp. 2215-2220 ◽  
Author(s):  
Mingshuang Xu ◽  
Yuhua Xin ◽  
Yong Yu ◽  
Jianli Zhang ◽  
Yuguang Zhou ◽  
...  

A novel Gram-negative, orange-pigmented, slightly halophilic, rod-shaped bacterium, strain T30T, was isolated from sediment from the South China Sea. Phylogenetic analysis showed that strain T30T was a member of the genus Erythrobacter, sharing highest 16S rRNA gene sequence similarities with Erythrobacter aquimaris JCM 12189T (99.5 %) and Erythrobacter vulgaris DSM 17792T (99.0 %). Levels of DNA–DNA relatedness between strain T30T and closely related strains of Erythrobacter species ranged from 14.5 to 56.9 %.The isolate lacked bacteriochlorophyll a and contained ubiquinone-10 as the predominant respiratory lipoquinone. The major fatty acids of this strain were C18 : 1 ω7c (38.2 %) and C16 : 1 ω7c /C16 : 1 ω6c (17.4 %). The major polar lipids were phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylcholine and phosphatidylglycerol. The DNA G+C content of strain T30T was 59.5 mol%. On the basis of phenotypic and phylogenetic data, a novel species, Erythrobacter nanhaisediminis sp. nov., is proposed; the type strain is T30T (=CGMCC 1.7715T=JCM 16125T).


Author(s):  
Fengqin Sun ◽  
Baojiang Wang ◽  
Yaping Du ◽  
Xiupian Liu ◽  
Qiliang Lai ◽  
...  

An aerobic, Gram-stain-negative, rod-shaped bacterial isolate, strain NH36AT, was isolated from a sandy sediment sample from the South China Sea. Colonies of the isolate were dark orange on M2 agar. Optimal growth was observed at pH 7.0–8.5, 30 °C and in the presence of 0.5–4.0 % (w/v) NaCl. The major fatty acids were C15 : 0, iso-C15 : 0, anteiso-C15 : 0, iso-C15 : 1, iso-C15 : 0 3-OH, iso-C17 : 0 3-OH and summed feature 3 (comprising iso-C15 : 0 2-OH and/or C16 : 1 ω7c). The DNA G+C content was 38.9 mol%. 16S rRNA gene sequence analysis revealed that strain NH36AT was most closely related to members of the genus Arenibacter, exhibiting 94.3–96.2 % sequence similarity to the type strains of Arenibacter species. On the basis of phenotypic, chemotaxonomic and phylogenetic data, this organism should be classified as a representative of a novel species in the genus Arenibacter. The name Arenibacter nanhaiticus sp. nov. is proposed and the type strain is NH36AT (=LMG 24842T=CCTCC AB 208315T=MCCC 1A04137T).


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