scholarly journals The Diversity, Composition, and Putative Functions of Gill-Associated Bacteria of Bathymodiolin Mussel and Vesicomyid Clam from Haima Cold Seep, South China Sea

2020 ◽  
Vol 8 (11) ◽  
pp. 1699
Author(s):  
Juan Ling ◽  
Hongxiang Guan ◽  
Lihua Liu ◽  
Jun Tao ◽  
Jie Li ◽  
...  
Keyword(s):  
South China Sea ◽  
South China ◽  
Phylogenetic Diversity ◽  
High Throughput Sequencing ◽  
Cold Seep ◽  
Rrna Gene ◽  
Cold Seeps ◽  
Element Cycling ◽  
China Sea ◽  
Vesicomyid Clam

The Haima cold seep, which is one of the two active cold seeps in the South China Sea, is known for its great ecological importance. The seep bivalves are assumed to depend mainly on their bacterial symbiosis for survival and growth. However, information on the bacterial diversity, composition, and putative function of gill-associated of dominant dwelling animals in Haima cold seep remain elusive. Herein, we adopted a high-throughput sequencing of 16S rRNA gene amplicons, and function prediction methods (Functional Annotation of Prokaryotic Taxa (FAPROTAX) and Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICURUSTs)) to purposely illustrate the taxonomic and phylogenetic diversity, composition, and putative functions of the symbionts in bathymodiolin mussel Gigantidas haimaensis (Bivalvia: Mytilidae: Gigantidas) and vesicomyid clam Archivesica marissinica (Bivalvia: Glossoidea: Vesicomyidae). The predominant microbes of both species were Proteobacteria and Gammaproteobacteria on the phylum and class level, respectively. The taxonomic and phylogenetic diversity of gill microbial communities in G. haimaensis were significantly different from those in A. marissinica (p < 0.05). Nine functional groups, including seven carbon-related biogeochemical groups, were identified through the FAPROTAX analysis. However, the most dominant groups for G. haimaensis and A. marissinica were both chemoheterotrophic. G. haimaensis and A. marissinica shared many pathways, however, 16 obtained Kyoto Encyclopedia of Genes and Genomes (KEGG) orthologous groups (42.11%) significantly differed between the two species (p < 0.05). These findings would provide insight into the functions of microbes in the element cycling and energy flow as well as the host-symbiont relationship of bivalves in the Haima cold seep environment.

scholarly journals Gas Hydrate Accumulation and Occurrence Associated with Cold Seep Systems in the Northern South China Sea: An Overview

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-24
Author(s):  
Wei Zhang ◽  
Jinqiang Liang ◽  
Qianyong Liang ◽  
Jiangong Wei ◽  
Zhifeng Wan ◽  
...  
Keyword(s):  
South China Sea ◽  
South China ◽  
Gas Hydrates ◽  
Gas Hydrate ◽  
Northern South China Sea ◽  
Cold Seep ◽  
Cold Seeps ◽  
Associated Gas ◽  
China Sea ◽  
Gas Bearing

Studying deep-water cold seep systems is of great significance to gas hydrate exploration due to their close relationship. Various cold seep systems and related gas hydrate accumulations have been discovered in the northern South China Sea in the past three decades. Based on high-resolution seismic data, subbottom profiles, in situ submergence observations, deep drilling and coring, and hydrate gas geochemical analyses, the geological and geophysical characteristics of these cold seep systems and their associated gas hydrate accumulations in the Qiongdongnan Basin, the Shenhu area, the Dongsha area, and the Taixinan Basin have been investigated. Cold seep systems are present in diverse stages of evolution and exhibit various seabed microgeomorphic, geological, and geochemical features. Active cold seep systems with a large amount of gas leakage, gas plumes, and microbial communities and inactive cold seep systems with authigenic carbonate pavements are related to the variable intensity of the gas-bearing fluid, which is usually derived from the deep strata through mud diapirs, mud volcanoes, gas chimneys, and faults. Gas hydrates are usually precipitated in cold seep vents and deeper vertical fluid migration pathways, indicating that deep gas-bearing fluid activities control the formation and accumulation of gas hydrates. The hydrocarbons collected from cold seep systems and their associated gas hydrate reservoirs are generally mixtures of biogenic gas and thermogenic gas, the origin of which is generally consistent with that of deep conventional gas. We also discuss the paragenetic relationship between the gas-bearing fluid and the seafloor morphology of cold seeps and the deep-shallow coupling of gas hydrates, cold seeps, and deep petroleum reservoirs. It is reasonable to conclude that the deep petroleum systems and gas-bearing fluid activity jointly control the development of cold seep systems and the accumulation of gas hydrates in the northern South China Sea. Therefore, the favorable areas for conventional oil and gas enrichment are also prospective areas for exploring active cold seeps and gas hydrates.

scholarly journals Environmental DNA Sequencing Reveals a Highly Complex Eukaryote Community in Sansha Yongle Blue Hole, Xisha, South China Sea

2019 ◽  
Vol 7 (12) ◽  
pp. 624
Author(s):  
Yueteng Liu ◽  
Hui He ◽  
Liang Fu ◽  
Qian Liu ◽  
Zuosheng Yang ◽  
...  
Keyword(s):  
South China Sea ◽  
South China ◽  
High Throughput Sequencing ◽  
Water Layer ◽  
Small Subunit ◽  
Reef Slope ◽  
Rrna Gene ◽  
Outer Reef ◽  
China Sea ◽  
Blue Hole

We report an Illumina high-throughput sequencing protocol of eukaryotic microbes in the world’s deepest marine blue hole, Sansha Yongle Blue Hole, Xisha, South China Sea. The variable V9 region of small subunit (SSU) rDNA, was sequenced using this approach from the waters of blue hole and outer reef slope. 917,771 unique eukaryotic 18S rRNA gene sequences and 6093 operational taxonomic units (OTUs) were identified. Significant differences in the eukaryotic composition were observed between the blue hole and outer reef slope, and the richness in the blue hole was much higher than that in the outer reef slope. The richness and diversity of eukaryotes in the blue hole were both lowest at 60 m and highest at 100 m depth. Eukaryotic microalgae assemblages dominated by Dinophyceae were the most abundant in the 10–20 m water column in the hole. Fauna was the main group at and below a depth of 60 m, where Araneae and Cyclopoida were dominant in the 60 m and 80 m water layer, respectively. There was a large number of Entoprocta at a depth of 180 m in the hole, where little oxygen was detected. Turbidity and nitrite concentration had a significant effect on the eukaryote community structure (p < 0.01).

scholarly journals A Quantitative Assessment of Methane-Derived Carbon Cycling at the Cold Seeps in the Northwestern South China Sea

Minerals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 256 ◽  
Author(s):  
Junxi Feng ◽  
Niu Li ◽  
Min Luo ◽  
Jinqiang Liang ◽  
Shengxiong Yang ◽  
...  
Keyword(s):  
South China Sea ◽  
South China ◽  
Bottom Water ◽  
Cold Seep ◽  
Anaerobic Oxidation Of Methane ◽  
Cold Seeps ◽  
Dissolved Carbon ◽  
China Sea ◽  
Seafloor Observation ◽  
Gas Hydrate Formation

Widespread cold seeps along continental margins are significant sources of dissolved carbon to the ocean water. However, little is known about the methane turnovers and possible impact of seepage on the bottom seawater at the cold seeps in the South China Sea (SCS). We present seafloor observation and porewater data of six push cores, one piston core and three boreholes as well as fifteen bottom-water samples collected from four cold seep areas in the northwestern SCS. The depths of the sulfate–methane transition zone (SMTZ) are generally shallow, ranging from ~7 to <0.5 mbsf (meters below seafloor). Reaction-transport modelling results show that methane dynamics were highly variable due to the transport and dissolution of ascending gas. Dissolved methane is predominantly consumed by anaerobic oxidation of methane (AOM) at the SMTZ and trapped by gas hydrate formation below it, with depth-integrated AOM rates ranging from 59.0 and 591 mmol m−2 yr−1. The δ13C and Δ14C values of bottom-water dissolved inorganic carbon (DIC) suggest discharge of 13C- and 14C-depleted fossil carbon to the bottom water at the cold seep areas. Based on a two-endmember estimate, cold seeps fluids likely contribute 16–26% of the bottom seawater DIC and may have an impact on the long-term deep-sea carbon cycle. Our results reveal the methane-related carbon inventories are highly heterogeneous in the cold seep systems, which are probably dependent on the distances of the sampling sites to the seepage center. To our knowledge, this is the first quantitative study on the contribution of cold seep fluids to the bottom-water carbon reservoir of the SCS, and might help to understand the dynamics and the environmental impact of hydrocarbon seep in the SCS.

scholarly journals Using Time-Series Videos to Quantify Methane Bubbles Flux from Natural Cold Seeps in the South China Sea

Minerals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 216
Author(s):  
Pengfei Di ◽  
Dong Feng ◽  
Jun Tao ◽  
Duofu Chen
Keyword(s):  
South China Sea ◽  
South China ◽  
Release Rate ◽  
The South China Sea ◽  
Cold Seep ◽  
Time Interval ◽  
Cold Seeps ◽  
The South ◽  
China Sea ◽  
Migration Pathways

Natural cold seeps are an important source of methane and other greenhouse gases to the ocean and atmosphere in the marine environment. Accurate quantification of methane bubble fluxes from cold seeps is vital for evaluating their influence on the global methane budget and climate change. We quantified the flux of gas bubbles released from two natural cold seep sites in the South China Sea: one seep vent in the Haima cold seeps (1400 m depth) and three seep vents at Site F (1200 m depth). We determined bubble diameter, size distribution, and bubble release rate using image processing techniques and a semiautomatic bubble-counting algorithm. The bubble size distributions fit well to log-normal distribution, with median bubble diameters between 2.54 mm and 6.17 mm. The average bubble diameters and release rates (4.8–26.1 bubbles s−1) in Site F was lower than that in Haima cold seeps (22.6 bubbles s−1), which may be attributed to a variety of factors such as the nature of the gas reservoir, hydrostatic pressure, migration pathways in the sediments, and pore size. The methane fluxes emitted at Haima cold seeps (12.6 L h−1) and at Site F (4.9 L h−1) indicate that the Haima and Site F cold seeps in the South China Sea may be a source of methane to the ocean. However, temporal variations in the bubble release rate and the geochemical characteristics of the seeps were not constrained in this study due to the short observational time interval.

scholarly journals Salegentibacter catena sp. nov., isolated from sediment of the South China Sea, and emended description of the genus Salegentibacter

2007 ◽  
Vol 57 (2) ◽  
pp. 219-222 ◽  
Author(s):  
Jiao-Yan Ying ◽  
Zhi-Pei Liu ◽  
Bao-Jun Wang ◽  
Xin Dai ◽  
Su-Sheng Yang ◽  
...  
Keyword(s):  
Fatty Acids ◽  
South China Sea ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
South China ◽  
The South China Sea ◽  
Rrna Gene ◽  
The South ◽  
China Sea ◽  
Emended Description

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.

6. Ecosystems of cold seeps in the South China Sea

2017 ◽  
Author(s):  
Mingyang Niu ◽  
Qianyong Liang ◽  
Dong Feng ◽  
Fengping Wang
Keyword(s):  
South China Sea ◽  
South China ◽  
The South China Sea ◽  
Cold Seeps ◽  
The South ◽  
China Sea

Multi-beam and seismic investigations of the active Haima cold seeps, northwestern South China Sea

2021 ◽  
Vol 40 (7) ◽  
pp. 183-197
Author(s):  
Bin Liu ◽  
Jiangxin Chen ◽  
Li Yang ◽  
Minliang Duan ◽  
Shengxuan Liu ◽  
...  
Keyword(s):  
South China Sea ◽  
South China ◽  
Cold Seeps ◽  
China Sea

A new species of Stygiopontius (Copepoda, Siphonostomatoida, Dirivultidae) from a deep-sea cold seep in the South China Sea

Crustaceana ◽  
2020 ◽  
Vol 93 (11-12) ◽  
pp. 1535-1546
Author(s):  
L. Ma ◽  
M.-X. Wang ◽  
X.-Z. Li
Keyword(s):  
New Species ◽  
South China Sea ◽  
South China ◽  
First Record ◽  
Plumose Seta ◽  
Endopodal Segment ◽  
Cold Seep ◽  
China Sea ◽  
Stout Spine ◽  
A New Species

Abstract A new species of the copepod genus Stygiopontius is described based on samples from a cold seep in northeastern South China Sea southwest to Taiwan, which were collected by the ROV Faxian with its mother vessel R/V Kexue in September 2017. The copepods were obtained by washing Shinkaia crosnieri Baba & Williams, 1998 (Decapoda: Munidopsidae) caught at a depth of 1124 m. The new species can be distinguished from its congeners by the combination of the following characteristics: caudal rami about 3.5 times as long as wide; basis of maxilliped with plumose seta, endopodal claw of maxilliped stout, with a row of fine spinules on inner margin; coxa of leg 1 with one inner seta; basis of leg 1 with stout spine exceeding to end of first endopodal segment; second endopodal segment of female leg 4 with pointed process; third exopodal segment of leg 4 with three outer spines. This is the first record of a Stygiopontius species from a cold seep.

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