Quantitative in situ Raman analysis of formate salt solutions at 25-350 °C and 0.1-40 MPa: implications for formate distribution on earth.

Formate (HCOO) is widely detected in diverse high-temperature geological environments, including hydrothermal vents and the deep lithosphere, where it plays a crucial role in supporting microbial communities. However, the thermal stability of formate remains poorly constrained, and a robust in situ Raman quantitative model for determining HCOO concentrations across a range of temperatures and pressures is lacking. In this study, we developed a Raman quantitative model for formate applicable at 25-350 °C and 0.

A large intraplate hydrogen-rich hydrothermal system driven by serpentinization in the western Pacific: Kunlun.

The Kunlun hydrothermal system near the Mussau Trench in the western Pacific consists of 20 large round/oval craters of hundreds of meters in diameter. The total area is 11.1 square kilometers, i.

Advancing anaerobic microbial studies with in situ Raman spectroscopy: Methanogenic archaea as a model.

Methanogenic archaea play a critical role in methane (CH) production and the global carbon cycle, yet accurately monitoring their gas metabolism under anaerobic conditions remains a technical challenge. In this study, we developed a Raman spectroscopy-based gas quantification model, achieving high-precision monitoring of CO-N-CH ternary gas mixtures over a temperature range of 12-52 °C. The model exhibited strong linear correlations between the Raman peak area ratios and gas molar ratios, which were further validated against gas chromatography, revealing no significant differences (p > 0.

In situ real-time pathway to study the polyethylene long-term degradation process by a marine fungus through confocal Raman quantitative imaging.

Since plastic waste has become a worldwide pollution problem, studying the ability of marine microorganisms to degrade plastic waste is important. However, conventional methods are unable to in situ real-time study the ability of microorganisms to biodegrade plastics. In recent years, Raman spectroscopy has been widely used in the characterization of plastics as well as in the study of biological metabolism due to its low cost, rapidity, label-free, non-destructive, and water-independent features, which provides us with new ideas to address the above limitations.

Novel SERS Probe Based on Ag Nanobean/Cu Foam for Deep-Sea Extreme Environment Biomolecule Detection.

Here, we report on progress made in coupling advances in surface-enhanced Raman scattering (SERS) techniques with a deep-ocean deployable Raman spectrometer. Our SERS capability is provided by development of a Cu foam-loaded silver-nanobean (Ag/Cu foam) which we have successfully coupled to the tip of a Raman probe head capable of insertion into deep-sea sediments and associated fluids. Our purpose is to expand the range of molecular species which can be detected in deep-sea biogeochemical environments, and our initial targets are a series of amino acids reportedly found in pore waters of seep locations.

Comparison of Raman spectral characteristics and quantitative methods between CH and CH from 25 to 400 °C and 50 to 400 bar.

In recent years, increasing attention has been given to quantifying the isotopic compositions of gases by Raman spectroscopy. However, related research on the carbon isotopes of CH is still lacking. In this study, the Raman spectral characteristics of CH and CH in the pure CH system and in the CH-HO system are comprehensively studied at temperatures ranging from 25 to 400 °C and pressures ranging from 50 to 400 bar.

Raman quantitative monitoring of methanogenesis: Culture experiments of a deep-sea cold seep methanogenic archaeon.

Gas production from several metabolic pathways is a necessary process that accompanies the growth and central metabolism of some microorganisms. However, accurate and rapid nondestructive detection of gas production is still challenging. To this end, gas chromatography (GC) is primarily used, which requires sampling and sample preparation.

Raman spectral characteristics of CO/CO and quantitative measurements of carbon isotopic compositions from 50 to 450 °C and 50 to 400 bar.

The carbon isotopic composition of CO is traced to its different origins and widely used in the fields of geology, biology, and chemistry. Raman spectroscopy can be performed in situ, is nondestructive, and requires no sample preparation; these characteristics enable Raman spectroscopy to be considered a new alternative method to measure the carbon isotopic composition of CO. In this work, Raman spectra of high-purity CO, CO, and six CO-CO binary mixtures with known mixing ratios were collected using a High Pressure Optical Cell (HPOC) at 50-450 °C and 50-400 bar.

Study of Microbial Sulfur Metabolism in a Near Real-Time Pathway through Confocal Raman Quantitative 3D Imaging.

As microbial sulfur metabolism significantly contributes to the formation and cycling of deep-sea sulfur, studying their sulfur metabolism is important for understanding the deep-sea sulfur cycle. However, conventional methods are limited in near real-time studies of bacterial metabolism. Recently, Raman spectroscopy has been widely used in studies on biological metabolism due to its low-cost, rapid, label-free, and nondestructive features, providing us with new approaches to solve the above limitation.

A deep-sea sulfate-reducing bacterium generates zero-valent sulfur via metabolizing thiosulfate.

Zero-valent sulfur (ZVS) is a crucial intermediate in the sulfur geobiochemical circulation and is widespread in deep-sea cold seeps. Sulfur-oxidizing bacteria are thought to be the major contributors to the formation of ZVS. However, ZVS production mediated by sulfate-reducing bacteria (SRB) has rarely been reported.

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

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.

Discovery of supercritical carbon dioxide in a hydrothermal system.

Supercritical CO appearing as bubbles in hydrothermal vents was identified in the south part of the Okinawa Trough using in situ Raman spectroscopy. Significantly, the N peak in supercritical CO is much larger than those in seawater and vent fluids, indicating that supercritical CO enriches N from the surrounding environment. Considering that the partial pressures of CO and N in the Earth's proto-atmosphere were ~10-20 MPa, supercritical CO with high N was likely the dominant CO phase near the water-air interface in the early history of the Earth, which promoted the synthesis, pre-enrichment and preservation of amino acids and other organic matters that are essential to the origin of life.

A novel bacterial thiosulfate oxidation pathway provides a new clue about the formation of zero-valent sulfur in deep sea.

Zero-valent sulfur (ZVS) has been shown to be a major sulfur intermediate in the deep-sea cold seep of the South China Sea based on our previous work, however, the microbial contribution to the formation of ZVS in cold seep has remained unclear. Here, we describe a novel thiosulfate oxidation pathway discovered in the deep-sea cold seep bacterium Erythrobacter flavus 21-3, which provides a new clue about the formation of ZVS. Electronic microscopy, energy-dispersive, and Raman spectra were used to confirm that E.

A New Approach to Measuring the Temperature of Fluids Reaching 300 ℃ and 2 mol/kg NaCl Based on the Raman Shift of Water.

The OH stretching band of water is very sensitive to temperature and salinity for the existence of hydrogen bonds between HO molecules. In this study, the OH stretching band was deconvoluted into two Gaussian peaks, with peak 1 at approximately 3450 cm and peak 2 at approximately 3200 cm. The positions of peaks 1 and 2 both shifted to higher wavenumbers with increasing temperature from 50 ℃ to 300 ℃.

A Direct Quantitative Raman Method for the Measurement of Dissolved Bisulfate in Acid-Sulfate Fluids.

Raman spectroscopy has been applied to the quantitative analysis of the concentration of bisulfate in acid-sulfate fluids at different temperatures. The quantitative analysis method is based on the peak area ratios of [Formula: see text](ν) and HO (ν), where PA([Formula: see text]/HO) = [[Formula: see text]] × (0.0066 × T + 1.

In Situ Raman Spectral Characteristics of Carbon Dioxide in a Deep-Sea Simulator of Extreme Environments Reaching 300 ℃ and 30 MPa.

Deep-sea carbon dioxide (CO) plays a significant role in the global carbon cycle and directly affects the living environment of marine organisms. In situ Raman detection technology is an effective approach to study the behavior of deep-sea CO. However, the Raman spectral characteristics of CO can be affected by the environment, thus restricting the phase identification and quantitative analysis of CO.