EXPRESS: A Piecewise Model for In Situ Raman Measurement of the Chlorinity of Deep-Sea High-Temperature Hydrothermal Fluids

2021 ◽  
pp. 000370282199911
Author(s):  
meng ge ◽  
Lianfu Li ◽  
Xin Zhang ◽  
Zhendong Luan ◽  
Zengfeng Du ◽  
...  

The chlorinity of deep-sea hydrothermal fluids, representing one of the crucial deep-sea hydrothermal indicators, indicates the degree of deep phase separation of hydrothermal fluids and water/rock reactions. However, accurately measuring the chlorinity of high-temperature hydrothermal fluids is still a significant challenge. In this paper, a piecewise chlorinity model to measure the chlorinity of high-temperature hydrothermal fluids was developed based on the OH stretching band of water, exhibiting an accuracy of 96.20%. The peak position, peak area ratio and F value were selected to establish the chlorinity piecewise calibration model within the temperature ranges of 0-50°C, 50-200°C and 200-300°C. Compared with that of the chlorinity calibration model built based on a single parameter, the accuracy of this piecewise model increased by approximately 4.83-12.33%. This chlorinity calibration model was applied to determine the concentrations of Cl for high-temperature hydrothermal fluids in the Okinawa Trough hydrothermal field.

2020 ◽  
Vol 40 (5) ◽  
pp. 556-562
Author(s):  
Hiromi K Watanabe ◽  
Chong Chen ◽  
Shigeaki Kojima ◽  
Shogo Kato ◽  
Hiroyuki Yamamoto

Abstract Genetic connectivity provides a basis for evaluating the resilience of animal communities by elucidating gene flow and serves as a proxy for realized dispersal through planktonic larval dispersal, settlement, and reproductive success. Gandalfus yunohana (Takeda, Hashimoto & Ohta, 2000) is a brachyuran crab endemic to deep-sea hydrothermal vents in the northwestern Pacific. Although an iconic and often dominant species, the connectivity among its populations is yet to be examined. We obtained barcoding sequences of the mitochondrial COI gene of G. yunohana from four vent fields including two on the Izu Arc, one on the northern Mariana Arc, and one in the Okinawa Trough. Genetic diversity of populations on the Izu and northern Mariana arcs were similar and shared the dominant haplotypes, showing no genetic subdivision regardless of the habitat depth. The Okinawa Trough population, for which only one specimen was available, was not genetically different from specimens from the Izu/Mariana arc populations. Estimation of the number of immigrants among populations suggests that the migration from north to south is higher than in the reverse direction. Our results resonate with previous laboratory-culture experiments, suggesting a high dispersal capability for G. yunohana. Visual observations and sampling, however, suggest that G. yunohana is exceedingly rare in the Okinawa Trough. This perhaps results from a lack of sufficient larval supply from the Izu-Bonin-Mariana Arc vents, and there may not be a reproductive population in the Okinawa Trough.


Author(s):  
Tomokazu Saruhashi ◽  
Masanori Kyo ◽  
Ikuo Sawada ◽  
Takahiro Yokoyama ◽  
Noriaki Sakurai ◽  
...  

2017 ◽  
Vol 5 (17) ◽  
Author(s):  
Chen Chen ◽  
Li Sun

ABSTRACT We report here the draft genome sequence of Exiguobacterium sp. HVEsp1, a thermophilic bacterium isolated from a deep-sea hydrothermal vent. The estimated genome size of this strain is 2,838,499 bp with a G+C content of 48.2%. The genome sequence data provide valuable information that will facilitate studies on the adaptation mechanisms of bacteria living in deep-sea hydrothermal vents.


2021 ◽  
Vol 8 ◽  
Author(s):  
Jun Liu ◽  
Haibin Zhang

Environmental DNA (eDNA) metabarcoding is an emerging tool to estimate diversity by combining DNA from the environmental samples and the high-throughput sequencing. Despite its wide use in estimating eukaryotic diversity, many factors may bias the results. Maker choice and reference databases are among the key issues in metabarcoding analyses. In the present study, we compared the performance of a novel 28S rRNA gene marker designed in this study and two commonly used 18S rRNA gene markers (V1-2 and V9) in estimating the eukaryotic diversity in the deep-sea sediments. The metabarcoding analyses based on the sediment surveys of the Okinawa Trough found that more eukaryotic taxa were discovered by 18S V9 than 28S and 18S V1-2, and that 18S V9 also performed better in metazoan recovery than the other two markers. Although a broad range of taxa were detected by the three metabarcoding markers, only a small proportion of taxa were shared between them even at the phylum level. The non-metric multidimensional scaling (NMDS) analysis also supported that communities detected by the three markers were distinct from each other. In addition, different communities were resolved by different reference databases (NCBI nt vs. SILVA) for the two 18S markers. Combining the three markers, annelids were found to be the most abundant (44.9%) and diverse [179 operational taxonomic units (OTUs)] metazoan group in the sediments of the Okinawa Trough. Therefore, multiple independent markers are recommended to be used in metabarcoding analyses during marine diversity surveys, especially for the poorly understood deep-sea sediments.


2018 ◽  
Vol 6 (15) ◽  
pp. e00254-18 ◽  
Author(s):  
Elena García-Valdés ◽  
Margarita Gomila ◽  
Magdalena Mulet ◽  
Jorge Lalucat

ABSTRACT Pseudomonas oceani DSM 100277T was isolated from deep seawater in the Okinawa Trough at 1390 m. P. oceani belongs to the Pseudomonas pertucinogena group. Here, we report the draft genome sequence of P. oceani, which has an estimated size of 4.1 Mb and exhibits 3,790 coding sequences, with a G+C content of 59.94 mol%.


2019 ◽  
Vol 14 (3) ◽  
pp. 150-160 ◽  
Author(s):  
Seiji Takeuchi ◽  
Ryota Nakajima ◽  
Takehisa Yamakita ◽  
Roxana Hoque ◽  
Tetsuya Miwa ◽  
...  

2018 ◽  
Vol 72 (11) ◽  
pp. 1621-1631 ◽  
Author(s):  
Lianfu Li ◽  
Xin Zhang ◽  
Zhendong Luan ◽  
Zengfeng Du ◽  
Shichuan Xi ◽  
...  

The OH stretching band of water is very sensitive to temperature and salinity for the existence of hydrogen bonds between H2O molecules. In this study, the OH stretching band was deconvoluted into two Gaussian peaks, with peak 1 at approximately 3450 cm−1 and peak 2 at approximately 3200 cm−1. The positions of peaks 1 and 2 both shifted to higher wavenumbers with increasing temperature from 50 ℃ to 300 ℃. The effects of salinity in the range of 0–2 mol/kg NaCl on the OH stretching band were also studied. Linearity for the relationship between Raman shift of peak 1 and temperature increased as the salt concentration increased from 0 to 2 mol/kg, while peak 2 displayed an opposing trend. Two temperature calibration models were developed based on the temperature-dependent changes in the Raman frequency shifts of peaks 1 and 2 (precision of 0.9 ℃ and 1.0 ℃, respectively). The calibration models for temperature were successfully applied to determining the temperatures of deep-sea hydrothermal fluids in the Okinawa Trough hydrothermal field. The degree of mixing of hydrothermal fluids and ambient seawater during in situ Raman measurements was estimated by the difference in temperatures determined through these calibration models and those measured through thermocouple sensors.


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