Molecular evidence for microorganisms participating in Fe, Mn, and S biogeochemical cycling in two low-temperature hydrothermal fields at the Southwest Indian Ridge

2013 ◽  
Vol 118 (2) ◽  
pp. 665-679 ◽  
Author(s):  
Jiwei Li ◽  
Xiaotong Peng ◽  
Huaiyang Zhou ◽  
Jiangtao Li ◽  
Zhilei Sun
Keyword(s):  
Low Temperature ◽  
Biogeochemical Cycling ◽  
Southwest Indian Ridge ◽  
Molecular Evidence ◽  
Indian Ridge ◽  
Hydrothermal Fields

Newly discovered hydrothermal fields along the ultraslow-spreading Southwest Indian Ridge around 63°E

2018 ◽  
Vol 37 (11) ◽  
pp. 61-67 ◽  
Author(s):  
Jie Chen ◽  
Chunhui Tao ◽  
Jin Liang ◽  
Shili Liao ◽  
Chuanwan Dong ◽  
...  
Keyword(s):  
Southwest Indian Ridge ◽  
Indian Ridge ◽  
Hydrothermal Fields

scholarly journals Microbial Sulfur Cycle in Two Hydrothermal Chimneys on the Southwest Indian Ridge

mBio ◽  
2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Huiluo Cao ◽  
Yong Wang ◽  
On On Lee ◽  
Xiang Zeng ◽  
Zongze Shao ◽  
...  
Keyword(s):  
Microbial Community ◽  
Sulfur Oxidation ◽  
Sulfur Cycle ◽  
Southwest Indian Ridge ◽  
Sulfate Reducing ◽  
Sulfur Oxidizing ◽  
Indian Ridge ◽  
Midocean Ridge ◽  
Reducing Bacteria ◽  
Hydrothermal Fields

ABSTRACT Sulfur is an important element in sustaining microbial communities present in hydrothermal vents. Sulfur oxidation has been extensively studied due to its importance in chemosynthetic pathways in hydrothermal fields; however, less is known about sulfate reduction. Here, the metagenomes of hydrothermal chimneys located on the ultraslow-spreading Southwest Indian Ridge (SWIR) were pyrosequenced to elucidate the associated microbial sulfur cycle. A taxonomic summary of known genes revealed a few dominant bacteria that participated in the microbial sulfur cycle, particularly sulfate-reducing Deltaproteobacteria. The metagenomes studied contained highly abundant genes related to sulfur oxidation and reduction. Several carbon metabolic pathways, in particular the Calvin-Benson-Bassham pathway and the reductive tricarboxylic acid cycles for CO2 fixation, were identified in sulfur-oxidizing autotrophic bacteria. In contrast, highly abundant genes related to the oxidation of short-chain alkanes were grouped with sulfate-reducing bacteria, suggesting an important role for short-chain alkanes in the sulfur cycle. Furthermore, sulfur-oxidizing bacteria were associated with enrichment for genes involved in the denitrification pathway, while sulfate-reducing bacteria displayed enrichment for genes responsible for hydrogen utilization. In conclusion, this study provides insights regarding major microbial metabolic activities that are driven by the sulfur cycle in low-temperature hydrothermal chimneys present on an ultraslow midocean ridge. IMPORTANCE There have been limited studies on chimney sulfides located at ultraslow-spreading ridges. The analysis of metagenomes of hydrothermal chimneys on the ultraslow-spreading Southwest Indian Ridge suggests the presence of a microbial sulfur cycle. The sulfur cycle should be centralized within a microbial community that displays enrichment for sulfur metabolism-related genes. The present study elucidated a significant role of the microbial sulfur cycle in sustaining an entire microbial community in low-temperature hydrothermal chimneys on an ultraslow spreading midocean ridge, which has characteristics distinct from those of other types of hydrothermal fields.

scholarly journals Formation and origin of Fe-Si oxyhydroxide deposits at the ultra-slow spreading Southwest Indian Ridge

2019 ◽  
Author(s):  
Kaiwen Ta ◽  
Zijun Wu ◽  
Xiaotong Peng ◽  
Zhaofu Luan
Keyword(s):  
Low Temperature ◽  
Secondary Ion Mass Spectrometry ◽  
Southwest Indian Ridge ◽  
Origin And Evolution ◽  
Biogenic Structures ◽  
Evolution Of Life ◽  
Electron Microscopy Analysis ◽  
Slow Spreading ◽  
Indian Ridge ◽  
Geologic Record

Abstract. Low-temperature hydrothermal system is dominated by Fe-Si oxyhydroxide deposits. However, the formation process and mechanism on modern hydrothermal Fe-Si oxyhydroxides at ultra-slow spreading centers remain poorly understood. The investigation presented in this paper focuses on six Fe-Si deposits collected from different sites at the Southwest Indian Ridge (SWIR). The mineralogical and geochemical evidence showed significant characteristics of a low-temperature hydrothermal origin. The Mössbauer spectra and iron speciation data further provided an insight into iron-bearing phases in all deposits. Two different types of biomineralized forms were discovered in these deposits by Scanning Electron Microscopy analysis. Energy-dispersive X-ray spectrometry and nano secondary ion mass spectrometry revealed that distinct biogenic structures were mainly composed of Fe, Si, and O, together with some trace elements. The Sr and Nd isotope compositions of Fe-Si deposits at the SWIR were closely related to interaction between hydrothermal fluids and seawater. The remarkably homogeneous Pb isotope compositions can be attributed to hydrothermal circulation. Based on these findings, we suggest that microbial activity plays a significant role in the formation of Fe-Si oxyhydroxides at the at ultra-slow spreading SWIR. Biogenic Fe-Si oxyhydroxides potentially provide insights into the origin and evolution of life in the geologic record.

scholarly journals He–Ar–S Isotopic Compositions of Polymetallic Sulphides from Hydrothermal Vent Fields along the Ultraslow-Spreading Southwest Indian Ridge and Their Geological Implications

Minerals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 512 ◽  
Author(s):  
Yan Wang ◽  
Zhongwei Wu ◽  
Xiaoming Sun ◽  
Xiguang Deng ◽  
Yao Guan ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Low Temperature ◽  
Sea Water ◽  
Hydrothermal Systems ◽  
Southwest Indian Ridge ◽  
Sulphide Minerals ◽  
Fast Spreading ◽  
The Indian Ocean ◽  
Indian Ridge ◽  
Sulphide Deposits

Noble gases have become a powerful tool to constrain the origin and evolution of ore-forming fluids in seafloor hydrothermal systems. The aim of this study was to apply these tracers to understand the genesis of newly discovered polymetallic sulphide deposits along the ultraslow-spreading Southwest Indian Ridge (SWIR). The helium, argon, and sulphur isotope compositions of metal sulphide minerals were measured for a number of active/inactive vent fields in the Indian Ocean. The helium concentrations and isotopic ratios in these ore samples are variable (4He: 0.09–2.42 × 10−8 cm3STP∙g−1; 3He: 0.06–3.28 × 10−13 cm3STP∙g−1; 3He/4He: 1.12–9.67 Ra) and generally greater than the modern atmosphere, but significantly lower than those in massive sulphides from the fast-spreading East Pacific Rise (EPR), especially for three Cu–Fe-rich samples from the ultramafic-hosted Tianzuo and Kairei vent fields. On the contrary, most of the SWIR sulphide deposits have somewhat higher 40Ar/36Ar ratios of trapped fluids (ranging from 290.6 to 303.4) when compared to the EPR ore samples. Moreover, the majority of sulphide minerals from the Indian Ocean have much higher δ34S values (3.0‰–9.8‰, ~5.9 on average, n = 49) than other basaltic-hosted active hydrothermal systems on the EPR. Overall, these He–Ar–S results are well within the range of seafloor massive sulphide deposits at global sediment-starved mid-ocean ridges (MORs), lying between those of air-saturated water (ASW) and mid-ocean ridge basalt (MORB) end members. Therefore, our study suggests that the helium was derived mainly from the MORB mantle by degassing during the high-temperature stage of hydrothermal activity, as well as from a mixture of vent fluids with variable amounts of ambient seawater during either earlier or late-stage low-temperature hydrothermal episodes, whereas the argon in ore-forming fluids trapped within sulphide minerals was predominantly derived from deep-sea water. Additionally, relatively high δ34S values exhibit a great estimated proportion (up to nearly 40%) of seawater-derived components. In summary, sub-seafloor extensive fluid circulation, pervasive low-temperature alteration, shallow seawater entrainment, and mixing processes, may make a larger contribution to the SWIR hydrothermal ore-forming systems, compared to fast-spreading centres.

Mineralogy and Chemistry of Sulfides from the Longqi and Duanqiao Hydrothermal Fields in the Southwest Indian Ridge

2018 ◽  
Vol 92 (5) ◽  
pp. 1798-1822 ◽  
Author(s):  
Baisong ZHANG ◽  
Zhenqing LI ◽  
Zengqian HOU ◽  
Weiyan ZHANG ◽  
Bo XU
Keyword(s):  
Southwest Indian Ridge ◽  
Indian Ridge ◽  
Hydrothermal Fields

scholarly journals A new peltospirid snail (Gastropoda: Neomphalida) adds to the unique biodiversity of Longqi vent field, Southwest Indian Ridge

2021 ◽  
Vol 55 (13-14) ◽  
pp. 851-866
Author(s):  
Chong Chen ◽  
Yuru Han ◽  
Jonathan T. Copley ◽  
Yadong Zhou
Keyword(s):  
Southwest Indian Ridge ◽  
Indian Ridge
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