A novel high-pressure low-temperature interface shear apparatus: Mechanical behavior of interface between hydrate-bearing sediment and foundation structure.

Metastable hydrates are widely distributed in shallow deep-sea sediments, posing significant risks to the long-term stability of offshore foundation structures. Unveiling the weakening mechanisms at the hydrate-bearing sediment-structure interface is crucial for establishing a theoretical framework for the safe design of deep-sea structures. A high-pressure (up to 12.

A new species of a rarely encountered genus Hartman, 1965 (Annelida, Scalibregmatidae) from the deep South China Sea.

In the present study, a new species of a rarely encountered genus Hartman, 1965, , is described based on specimens collected from slope depths of the northern South China Sea. It is characterized by the presence of branched branchiae and heavy acicular spines in the anterior chaetigers, and is morphologically distinct from the other species of the genus in the shape of the anterior margin of the prostomium, the number of neuropodia with nipple-like projections distally, and the segment annulation. Four gene fragments of the new species were sequenced, comprising 16S rRNA, 18S rRNA, 28S rRNA, and histone H3.

Impact of land use changes on selenium distribution and bioavailability in Mollisol of Sanjiang Plain.

Recent changes in land use in the Mollisol region of the Sanjiang Plain have significantly impacted speciation and bioavailability of selenium (Se) in soils. This study examines Se species and distribution across various land use types, focusing on the interactions between iron oxides and organic matter in Se migration and transformation. The total Se content in woodland, dryland, and paddy soils is 0.

Black Carbon Formation at Cold Seeps and Its Potential Contribution to the Marine Black Carbon Budget.

The long-term carbon sequestration capacity of black carbon (BC) is among the factors controlling climate change dynamics. Culture experiments have revealed that anaerobic methanotrophic archaea (ANME) can produce BC, but their impact on the marine BC cycle has not been thoroughly investigated. This study examined the geochemical properties of BC preserved in seep carbonates from the South China Sea and the Gulf of Mexico.

Geogenic fluorine-contaminated groundwater increases fluorosis risk in communities of northern cold regions: Genesis mechanism and exposure pathways.

Geogenic fluorine-contaminated groundwater (F >1 mg/L) prevails in cold Mollisol regions of the world. Seasonal variation of F concentration in groundwater likely renders multiple pathways of toxic-level F exposure, posing unrecognized health risk to many economically challenged communities. Herein, different types of samples within the groundwater-soil-crop-human hair network were collected from the Mollisol regions of northeastern China and assessed by joint approach of medical geochemical assay, hydrogeochemical modeling, and health risk indexation.

Characterizing organophosphate esters and chlorinated paraffins in surface soils affected by diverse e-waste disassembling process in South China: Occurrence, distinct emission, and risk assessment.

E-waste recycling activities are a crucial emission source of organic pollutants, posing potential risks to the surrounding environment and human health. To understand the potential impact related to diverse e-waste dismantling activities, we investigated two categories of popular flame retardants (i.e.

Mollisol Erosion-Driven Efflux of Energetic Organic Carbon and Microflora Increases Greenhouse Gas Emissions from Cold-Region Rivers.

Massive soil erosion occurs in the world's Mollisol regions due to land use change and climate warming. The migration of Mollisol organic matter to river systems and subsequent changes in carbon biogeochemical flow and greenhouse gas fluxes are of global importance but little understood. By employing comparative mesocosm experiments simulating varying erosion intensity in Mollisol regions of northeastern China, this research highlights that erosion-driven export and biomineralization of terrestrial organic matter facilitates CO and CH emission from receiving rivers.

Lipidomic diversity and proxy implications of archaea from cold seep sediments of the South China Sea.

Cold seeps on the continental margins are characterized by intense microbial activities that consume a large portion of methane by anaerobic methanotrophic archaea (ANME) through anaerobic oxidation of methane (AOM). Although ANMEs are known to contain unique ether lipids that may have an important function in marine carbon cycling, their full lipidomic profiles and functional distribution in particular cold-seep settings are still poorly characterized. Here, we combined the 16S rRNA gene sequencing and lipidomic approaches to analyze archaeal communities and their lipids in cold seep sediments with distinct methane supplies from the South China Sea.

Metal-Driven Anaerobic Oxidation of Methane as an Important Methane Sink in Methanic Cold Seep Sediments.

Anaerobic oxidation of methane (AOM) coupled with reduction of metal oxides is supposed to be a globally important bioprocess in marine sediments. However, the responsible microorganisms and their contributions to methane budget are not clear in deep sea cold seep sediments. Here, we combined geochemistry, muti-omics, and numerical modeling to study metal-dependent AOM in methanic cold seep sediments in the northern continental slope of the South China Sea.

A new eyeless species of (Annelida, Nereididae) from deep-sea sediments of the northern South China Sea.

A variety of nereidid species have been reported from the South China Sea, although little is known about the deep-sea species in this area. Recently, two specimens belonging to a novel nereidid polychaete were collected from a sedimentary habitat during an environmental survey to a deep-sea basin where cold seeps occur. This new species, , is described herein, based on morphological and molecular analyses.

Corrigendum: Active Anaerobic Archaeal Methanotrophs in Recently Emerged Cold Seeps of Northern South China Sea.

[This corrects the article DOI: 10.3389/fmicb.2020.

Active Anaerobic Archaeal Methanotrophs in Recently Emerged Cold Seeps of Northern South China Sea.

Cold seep ecosystems are developed from methane-rich fluids in organic rich continental slopes, which are the source of various dense microbial and faunal populations. Extensive studies have been conducted on microbial populations in this unique environment; most of them were based on DNA, which could not resolve the activity of extant organisms. In this study, RNA and DNA analyses were performed to evaluate the active archaeal and bacterial communities and their network correlations, particularly those participating in the methane cycle at three sites of newly developed cold seeps in the northern South China Sea (nSCS).

Methyl-compounds driven benthic carbon cycling in the sulfate-reducing sediments of South China Sea.

Methane is a potent greenhouse gas; methane production and consumption within seafloor sediments has generated intense interest. Anaerobic oxidation of methane (AOM) and methanogenesis (MOG) primarily occur at the depth of the sulfate-methane transition zone or underlying sediment respectively. Methanogenesis can also occur in the sulfate-reducing sediments through the utilization of non-competitive methylated compounds; however, the occurrence and importance of this process are not fully understood.

Characteristics of phytoplankton communities and their biomass variation in a gas hydrate drilling area in the northern South China Sea.

We analyzed the data obtained from field observations on a gas hydrate drilling area in Dongsha of northern South China Sea (SCS) in middle May (before drilling) and early October (after drilling) in 2013. The variation in the phytoplankton communities and biomass as well as the impacts of environmental factors including dissolved methane was studied. Results indicated that the gas hydrate drilling area in Dongsha, SCS exhibited a typical low-nutrients low-chlorophyll a (LNLC) environment accompanied with low phytoplankton abundance.

The mitochondrial genome of the deep-sea tubeworm (Siboglinidae, Annelida) and its phylogenetic implications.

is a conspicuous annelid living in the cold seeps and hydrothermal vents of the Western Pacific region and relying on their endosymbiont bacteria as a source of energy and organic carbon. We report the complete mitochondrial genome of , which is 15,280 bp in length, containing 13 protein-coding genes, two ribosomal RNA genes, 22 tRNA genes and a putative control region. The overall base composition is AT-biased.

Methane-metabolizing microbial communities in sediments of the Haima cold seep area, northwest slope of the South China Sea.

Cold seeps are widespread chemosynthetic ecosystems in the deep-sea environment, and cold seep microbial communities of the South China Sea are poorly constrained. Here we report on the archaeal communities, particularly those involved in methane metabolization, in sediments of a newly discovered cold seep (named 'Haima') on the northwest slope of the South China Sea. Archaeal diversity, abundance and distribution were investigated in two piston cores collected from a seep area (QDN-14B) and a non-seep control site (QDN-31B).

High occurrence of Bathyarchaeota (MCG) in the deep-sea sediments of South China Sea quantified using newly designed PCR primers.

The archaeal phylum Bathyarchaeota, which is composed of a large number of diverse lineages, is widespread and abundant in marine sediments. Environmental factors that control the distribution, abundance and evolution of this largely diversified archaeal phylum are currently unclear. In this study, a new pair of specific primers that target the major marine subgroups of bathyarchaeotal 16S rRNA genes was designed and evaluated to investigate the distribution and abundance of Bathyarchaeota in marine sediments.

A new species of Hemichela Stock, 1954 from the South China Sea (Arthropoda, Pycnogonida, Ammotheidae).

A new species of pycnogonid collected by the Chinese research vessel, R/V HY IV, during deep sea cruises to the South China Sea in 2013, is described. The new species, Hemichela nanhaiensis, obtained from more than 1300 m depth, is distinguished from the other two species in the genus by the characters of the chela dactylus with 12 denticulations on the inner margin and by the presence of taller tubercles on the lateral processes.

Application of headspace single-drop microextraction coupled with gas chromatography for the determination of short-chain fatty acids in RuO4 oxidation products of asphaltenes.

In this study, headspace single-drop microextraction (HS-SDME) coupled with gas chromatography-flame ionization detection (GC-FID), was employed to determine short-chain fatty acids (SCFAs) in ruthenium tetroxide (RuO(4)) oxidation products of asphaltenes. Several significant parameters, such as drop solvent type, drop volume, sample solution ionic strength, agitation speed, extraction time, and ratio of headspace volume to sample volume were optimized. Under optimum extraction conditions (i.

Application of hollow fiber liquid-phase microextraction in identification of oil spill sources.

In this study, hollow fiber based liquid-phase microextraction (HF-LPME), coupled with GC, GC-MS and GC-IRMS detections, was employed to determine petroleum hydrocarbons in spilled oils. According to the results, the HF-LPME method collected more low-molecular weight components, such as C(7)-C(11)n-alkanes, naphthalene, and phenanthrene, than those collected in conventional liquid-liquid extraction (LLE). The results also showed that this method had no remarkable effect on the distributions of high-molecular weight compounds such as >C(18)n-alkanes, C(1)-C(3) phenanthrene, and hopanes.