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Acoustic echosounding systems are increasingly used to image water-column backscatter in addition to mapping the seafloor. We have imaged an acoustic flare generated by methane bubbles emanating from a vent sourced at 1840 m water depth offshore northern California using a shipboard Kongsberg EM122. Data include five transits over the flare and approximately 11 h of continuous observation when the ship held station. Shipboard observations showed a strong flare splitting into multiple smaller, intermittent flares at a water depth of 800–1200 m and pronounced temporal variability. We introduce a new approach to processing the data in which we correct the backscatter data for ship motion and bin the data into voxels with dimensions of 20 m in X and Y and 40 m in Z for a transit over the flare and into vertical slices with dimensions of 15 m in X and Z and 4 min in time when the ship was stationary. The processed data indicate that the signal is dominated by bubbles emanating from a source region with a diameter of approximately 40 m located on the southern edge of what is likely a ring of sources with a diameter of approximately 600 m. When the ship was stationary, we were able to track an individual pulse rising at a rate of 8–10 m/min. Our results illustrate the limitations of monitoring temporal variation in gas flux using multibeam echosounders because of the trade-off between imaging the entire flare by averaging over tens of minutes to hours and observing a slice through the flare to capture short-lived pulses of gas expulsion. Nevertheless, because echosounders are widely available, they can continue to provide valuable data on the spatial and temporal distribution of gas emissions on continental margins that can be used to frame hypotheses and plan more comprehensive follow-up experiments.

From 2015 to 2018, TGS conducted a comprehensive multiclient oil and gas seep mapping survey in the Gulf of Mexico (GOM). The basis for identifying seeps on the sea bottom was a high-resolution multibeam echosounder survey, mapping approximately 880,000 km2 of the sea bottom deeper than 750 m water depth, at a bathymetric resolution of 15 m, and a backscatter resolution of 5 m. We identified more than 5000 potential oil and/or gas seeps, and of those, we cored approximately 1500 for hydrocarbon geochemical analysis. The sea bottom features best related to hydrocarbon seepage in the GOM are high backscatter features, mud volcanoes, pock marks, brine pools, “popcorn” texture, fault traces, and anticlinal crests. We also tracked gas plumes in the water column back to the sea bottom to provide an additional criterion for hydrocarbon seepage. Cores from sea bottom targets recovered liquid oil, tar, and gas hydrates. Oil extract and gas analyses of samples from most target types produced values substantially higher than background in both oil and gas.

This study investigates the effects of long-term exposure to OA on skeletal parameters of four tropical zooxanthellate corals naturally living at CO2 seeps and adjacent control sites from two locations (Dobu and Upa Upasina) in the Papua New Guinea underwater volcanic vent system. The seeps are characterized by seawater pH values ranging from 8.0 to about 7.7. The skeletal porosity of Galaxea fascicularis, Acropora millepora, massive Porites, and Pocillopora damicornis was higher (up to ~ 40%, depending on the species) at the seep sites compared to the control sites. Pocillopora damicornis also showed a decrease of micro-density (up to ~ 7%). Thus, further investigations conducted on this species showed an increase of the volume fraction of the larger pores (up to ~ 7%), a decrease of the intraskeletal organic matrix content (up to ~ 15%), and an increase of the intraskeletal water content (up to ~ 59%) at the seep sites. The organic matrix related strain and crystallite size did not vary between seep and control sites. This multi-species study showed a common phenotypic response among different zooxanthellate corals subjected to the same environmental pressures, leading to the development of a more porous skeletal phenotype under OA.

Global pollution can only handle with education in early childhood. Especially, the pre-school period is an important time for environmental education. It is seen that current pre-school education programs generally include environmental education but it has missing parts. The aim of the study is to add the built environment elements to the environmental education programs that include only natural elements such as trees, animals, etc. The environment is basically divided into two parts as natural and built (man-made structures). There is no environmental education program in the literature that includes these two basic subjects. The built environment includes architectural elements such as buildings, bridges, and infrastructure systems. All people use these systems and should have knowledge about them. The complete Sustainable Environmental Education Model has been created which is including both natural and built environmental elements for preschool pupils in the study. The LEED criteria were taken as a reference while planning the model. The model was applied to 134 (5 years old) pupils who studying pre-school education for eight months. As a result of the model application, the level of awareness of pupils who have never study any environmental education before, according to the beginning of the program, is from 23.37% to 79.81% in sustainable areas, from 23.87% to 85.32% in "efficient water use", from 13.80% to 91.79% in efficient energy use and from 13.78% to 82.98% in the usage of waste materials It was determined that it increased. The designed model can be the solution for global pollution.

Recently discovered fields of seeps in western Siberia are an important, previously unknown source of methane. Seeps are located in the floodplains of small rivers and vary in shape, size and localization. Methane fluxes from seeps may be high, making them the sources of high regional importance. However, the data on the seep bacterial community composition are scarce, concentrating mainly on methanotrophic bacteria. In the present work, the overall bacterial diversity in the sediments of shallow-water seeps at the floodplain of the Bolshaya Rechka River was studied using high-throughput 16S rRNA gene sequencing. Molecular analysis revealed that Gammaproteobacteria and Actinobacteria were the most abundant bacterial groups (28.5–33.8 and 11–13.2% of total 16S rRNA genes, respectively). A significant part of the sequences belonged to Chloroflexi, Desulfobacterota, and Bacteroidota. Acidobacteriota and Verrucomicrobiota were responsible for 1.5–2.7 and 1.0–1.9%, respectively. The methanotrophic community was dominated by bacteria of the genus Methylobacter. The most numerous species-level OTU (8% of all 16S rRNA gene sequences) belonged to Methylobacter tundripaludum (97% identity). Methanotrophic Alphaproteobacteria were not detected in the seeps. Our results confirm the presence of an active bacterial community in the sediments of shallow-water seeps, with predominance of methanotrophic Gammaproteobacteria.

In order to reconstruct the ecosystem structure of chemosynthetic environments in the fossil record, geochemical proxies must be developed. Here, we present a suite of novel compound-specific isotope parameters for tracing chemosynthetic production with a focus on understanding nitrogen dynamics in deep-sea cold seep environments. We examined the chemosymbiotic bivalve Bathymodiolus childressi from three geographically distinct seep sites on the NE Atlantic Margin and compared isotope data to non-chemosynthetic littoral mussels to test whether water depth, seep activity, and/or mussel bed size are linked to differences in chemosynthetic production. The bulk isotope analysis of carbon (δ13 C) and nitrogen (δ15 N), and δ15 N values of individual amino acids (δ15 NAA ) in both gill and muscle tissues, as well as δ15 NAA- derived parameters including trophic level (TL), baseline δ15 N value (δ15 NPhe ), and a microbial resynthesis index (ΣV), were used to investigate specific geochemical signatures of chemosynthesis. Our results show that δ15 NAA values provide a number of new proxies for relative reliance on chemosynthesis, including TL, ∑V, and both δ15 N values and molar percentages (Gly/Glu mol% index) of specific AA. Together, these parameters suggested that relative chemoautotrophy is linked to both degree of venting from seeps and mussel bed size. Finally, we tested a Bayesian mixing model using diagnostic AA δ15 N values, showing that percent contribution of chemoautotrophic versus heterotrophic production to seep mussel nutrition can be directly estimated from δ15 NAA values. Our results demonstrate that δ15 NAA analysis can provide a new set of geochemical tools to better understand mixotrophic ecosystem function and energetics, and suggest extension to the study of ancient chemosynthetic environments in the fossil record.

The first results of a study into the microbiomes of benthic invertebrates found in sites with seeps (containing methane, oil, or a combination of methane and mud) and an underwater low-temperature vent of Lake Baikal are presented. Microorganisms were detected in the intestine of an oligochaete from the cold methane seep using microscopy. Analysis of 16S rRNA gene libraries revealed that the highest diversity of microorganisms was found in the nematode microbiomes where the members of 11 phyla were identified. Some of the detected prokaryotes are methanogens, nitrifiers, and nitrogen fixators, while some are involved in the sulfur cycle. Methanotrophs were detected in the microbiomes of oligochaetes and chironomids. The microbiomes of nematodes, chironomids, and bathynellids are composed of members of the Bacteroidetes and Firmicutes phyla, which are related to the symbiotic bacteria found in insects and animals from other ecotopes. Microorganisms typically found in the water and sediments of Lake Baikal were also detected in the invertebrates microbiomes.

The genus Trischizostoma Boeck, 1861 is a cosmopolitan group of parasitic and symbiotic aristoidean amphipods whose distribution is poorly known, with scarce specimens reported principally from pelagic environments until 3655 m depth. In this note, Trischizostoma crosnieri Lowry & Stoddart,1993, a species described for the southwest Pacific, is recorded for the first time in the southeast Pacific. The species was known previously only from a female specimen, described from the Philippines, with two additional unpublished records from the east coast of Australia and Tasmania. The specimens studied herein were obtained at 874 m depth, 36 nm to the northwest of Concepción, Biobío Region, in a methane seep site. However, the relationship between this species with this particular habitat is still uncertain. The genus Trischizostoma has been cited for the Nazca and Salas y Gómez ridges; nevertheless, our finding constitutes the first record of a species at the continental margin off Chile, raising to four the known species of the genus for Chilean waters.

Aquifers are dug very deep in many areas. When they are near the sea or an island the sea water tends to seep to the aquifers. This ultimately leads the aquifers to be salty and hence they don’t achieve the objective of providing fresh water to the community. This study was conducted in 2020 with a name of coming up with preventive measures of the sea water seepage to the aquifers. This paper is only a review paper of how far the impact can be felt as the data is being analyzed.

Despite the obvious link between hydrocarbon seepage at the surface and the activity of petroleum systems at depth, the majority of studies on seep carbonates concentrate on shallow aspects, whereas they are rarely oriented toward a source-to-sink perspective. Here, seep carbonates are conceptualized as a key element for analyzing petroleum systems at basin scale. Mapping of a 150-m-thick, 200-m-wide outcrop of the Lower Cretaceous slope wedge of the southeastern France Basin reveals two distribution patterns of seep carbonate concretions: (1) aligned in a continuous bed secant to the stratigraphy and (2) clustered in patches vertically stacked over 35 m. The δ13C signatures of the seep carbonates as light as −40‰ Peedee belemnite point toward a biogenic methane–dominated seepage. A set of turbidite channels pinching out right below the seep carbonates is seen as a potential gas trap, whereas biostratigraphic analysis indicates that the channels are coeval with a prominent black shale in the center of the basin. Any biogenic methane generated by the black shale could have used the channels as drains up to their pinch-out. The switch from a continuous seep carbonate level to stacked patches suggests initial widespread capillary leakage, followed by the opening of a preferential migration pathway. The distribution of seep carbonates thus appears dominated by breaching mechanisms of reservoir–cap-rock seals. This case study illustrates how seep carbonate mapping, in combination with the tectono-sedimentary context of each basin, may be a valuable tool for petroleum geologists.

Methane oxidation rates and diversity of methane-oxidizing microorganisms were studied in the upper sediment layers of the Laptev Sea (methane seep area, Lena fore-delta, shelf, and upper slope not affected by seeps and river flow). The highest methane concentrations and methane oxidation rates (up to 1.16 µmol СН4 dm−3 day−1) were revealed at the seep stations. Carbon dioxide was the main product of methane oxidation at all stations. Sequencing of the 16S rRNA gene fragments revealed microorganisms of the class Gammaproteobacteria, order Methylococcales. Since the share of methanotrophs was high at the sites of constant gas seepage (up to 1.93% of the total read number), they could be detected by sequencing of the native samples. Phylogenetic diversity of methane-oxidizing bacteria was not high, and all detected microorganisms belonged to the Deep-Sea 1 cluster. On the phylogenetic tree, the sequences formed a cluster together with the genus Methyloprofundus. Members of the genera Methylomonas and Methylobacter related to methanotrophs inhabiting freshwater ecosystems were revealed in enrichments from the coastal stations sediment samples.

The origin, migration pathways, as well as the influence of secondary processes of oil and natural gas accumulated in lower Cretaceous to lower Miocene strata of the western part of the Polish Outer Carpathians (between Kraków and Pilzno towns) based on results of organic geochemical analyses are investigated in this paper. Oil and thermogenic hydrocarbon gases were generated mainly from type II kerogen, and type II and III kerogen mixed in various proportions. These kerogens mainly occur in the Oligocene Menilite beds of the Silesian and Dukla nappes. Oils were generated from early to late “oil window”. Secondary cracking was recorded in oils from Dukla nappe, other secondary processes including biodegradation, water washing and evaporative fractionation were also developed to a various extent in many oils. The most biodegraded oils occur in seep S-Li, and the most extensive water washing is observed in the oil from seep S-Sa/1. The evaporative fractionation processes most significantly occur in the selected deepest parts of the multi-horizontal Biecz field. Hydrocarbon gases originated during both microbial and thermogenic processes of organic matter transformation. Natural gas has not been subjected to biodegradation processes. Carbon dioxide is derived from both microbial and thermogenic decomposition processes of organic matter and was generated together with hydrocarbon gases.

The regularities of the distribution of aliphatic and cyclic petroleum hydrocarbon biomarkers in different individual prokaryotes and their communities are considered. Individual bacteria (Arthrobacter sp. RV, Pseudomonas aeruginosa RM, Spirulina (Arthrospira) platensis, individual bacteria isolated from the oil of the Daqing field in the People’s Republic of China (Geobacillus jurassicus and Shewanella putrefaciens), individual archaea (Thermoplasma sp.) and microbial communities isolated from the oil seep of the Oil Site of the Uzon volcano caldera (Kamchatka, Russia), and relics of cyanobacterial mats (CBM) isolated from the Lower Cambrian reservoir rocks of the Ichyodinskoye oil field (Eastern Siberia) have been studied. It is shown that the studied bacteria and archaea make different contributions to the formation of hydrocarbons–biomarkers of oil. In particular, it is proposed that the oil seep at the Oil Site of the Uzon volcano caldera (Kamchatka) and the Precambrian oil of the Ichyodinskoye oil field (Eastern Siberia) were formed from prokaryotes.

In marine ecosystems, viruses exert control on the composition and metabolism of microbial communities, thus influencing overall biogeochemical cycling. Deep sea sediments associated with cold seeps are known to host taxonomically diverse microbial communities, but little is known about viruses infecting these microorganisms. Here, we probed metagenomes from seven geographically diverse cold seeps across global oceans, to assess viral diversity, virus-host interaction, and virus-encoded auxiliary metabolic genes (AMGs). Gene-sharing network comparisons with viruses inhabiting other ecosystems reveal that cold seep sediments harbour considerable unexplored viral diversity. Most cold seep viruses display high degrees of endemism with seep fluid flux being one of the main drivers of viral community composition. In silico predictions linked 14.2% of the viruses to microbial host populations, with many belonging to poorly understood candidate bacterial and archaeal phyla. Lysis was predicted to be a predominant viral lifestyle based on lineage-specific virus/host abundance ratios. Metabolic predictions of prokaryotic host genomes and viral AMGs suggest that viruses influence microbial hydrocarbon biodegradation at cold seeps, as well as other carbon, sulfur and nitrogen cycling via virus-induced mortality and/or metabolic augmentation. Overall, these findings reveal the global diversity and biogeography of cold seep viruses and indicate how viruses may manipulate seep microbial ecology and biogeochemistry.

Soil bacteria rank among the most diverse groups of organisms on Earth and actively impact global processes of carbon cycling, especially in the emission of greenhouse gases like methane, CO2 and higher gaseous hydrocarbons. An abundant group of soil bacteria are the mycobacteria, which colonize various terrestrial, marine and anthropogenic environments due to their impermeable cell envelope that contains remarkable lipids. These bacteria have been found to be highly abundant at petroleum and gas seep areas, where they might utilize the released hydrocarbons. However, the function and the lipid biomarker inventory of these soil mycobacteria are poorly studied. Here, soils from the Fuoco di Censo seep, an everlasting fire (gas seep) in Sicily, Italy, were investigated for the presence of mycobacteria via 16S rRNA gene sequencing and fatty acid profiling. The soils contained high relative abundances (up to 34 % of reads assigned) of mycobacteria, phylogenetically close to the Mycobacterium simiae complex and more distant from the well-studied M. tuberculosis and hydrocarbon-utilizing M. paraffinicum. The soils showed decreasing abundances of mycocerosic acids (MAs), fatty acids unique for mycobacteria, with increasing distance from the seep. The major MAs at this seep were tentatively identified as 2,4,6,8-tetramethyl tetracosanoic acid and 2,4,6,8,10-pentamethyl hexacosanoic acid. Unusual MAs with mid-chain methyl branches at positions C-12 and C-16 (i.e., 2,12-dimethyl eicosanoic acid and 2,4,6,8,16-pentamethyl tetracosanoic acid) were also present. The molecular structures of the Fuoco di Censo MAs are different from those of the well-studied mycobacteria like M. tuberculosis or M. bovis and have relatively δ13C-depleted values (−38 ‰ to −48 ‰), suggesting a direct or indirect utilization of the released seep gases like methane or ethane. The structurally unique MAs in combination with their depleted δ13C values identified at the Fuoco di Censo seep offer a new tool to study the role of soil mycobacteria as hydrocarbon gas consumers in the carbon cycle.

A new pardaliscid amphipod, Princaxelia marianaensissp. nov., is described from a single female captured at the Shinkai Seep Field, Mariana Trench, from a depth of 5,689–5,683 m. A key to species of Princaxelia is provided. This is the first species of Princaxelia to be described from the Mariana Trench, and the second report of this genus from this region.

Methane seepage along continental margins has been linked to climatic warming, yet it is uncertain whether such seepage took place during the Permian, a period that witnessed a transition from an icehouse to a greenhouse world. To address this issue, we investigated calcareous concretions and layers within mudstones/shales of the Kungurian Angie Formation in the Xainza area, central Tibet. A combination of petrographic, mineralogical, elemental, and carbon‑sulfur isotopic analyses provide strong evidence for a hydrocarbon-seep origin of these carbonates, with thermogenic methane and crude oil being the most likely carbon sources. Our dataset also indicates that, although fueled by a common deep-buried hydrocarbon reservoir, these layers and concretions experienced different biogeochemical processes due to variable rates of cold-seep fluid flux combined with persistently low sulfate concentrations in bottom waters of the Bangong-Nujiang Tethyan Ocean. A biogeochemical switch from sulfate-dependent to iron oxide-coupled anaerobic oxidation of methane in the sulfate-methane transition zone, likely triggered by sulfate exhaustion, was inferred to affect carbonate layer formation near the sediment-water interface. If true, this switch, together with common vent structures, would have resulted in escape of large amounts of methane directly to the ocean-atmosphere system. The hydrocarbon seeps in the central Lhasa Block was approximately coeval with rapid climate warming in the peri-Gondwanan region during the early Kungurian. Although further investigations are required in the future, this study demonstrates a possible causal relationship between regional tectonic evolution, hydrocarbon seepage, and global climate change.

A single terebratulide brachiopod valve found in a middle Eocene limestone deposit in the Humptulips Formation in western Washington State is the first record of a megathyridid brachiopod in a hydrocarbon seep deposit, the first fossil record of the genus Argyrotheca in western North America, and the northernmost record for Argyrotheca from the north-eastern Pacific Ocean.

The aim of the study. To assess the echocardiographic signs of structural and left heart functional changes in the working age individuals with obstructive sleep apnea syndrome. Materials and methods. Cross-sectional prospective observational study of 67 working age individuals was performed. The main group included 45 patients diagnosed with obstructive sleep apnea syndrome. The control group consisted of 22 subjects without any pathology revealed by means of polysomnography. There were no significant differences in gender, age, body mass index, presence of diabetes mellitus, arterial hypertension in patients of both groups. To assess the structural and functional changes in the left heart all subjects underwent echocardiographic heart examination in M and B modes, pulse-wave and tissue Doppler study. Results. According to echocardiographic studies of working age patients with OSAS, the anteroposterior size of the left atrium (LA) and the LA volume index are statistically significantly higher than those in the control group: 38.0 (36.0 - 40.0) mm versus 35.0 (30, 3 - 38.0) mm (p

Measurements of the methane fluid discharge from bottom sediments and daily monitoring of the main hydrophysical parameters near the site of the bubble gas discharge (seeps) in Laspi Bay have been carried out. Fluid flow values varied by an order of magnitude (1.4–74.3 mmol/(m $${}^{2}$$ day)) at points separated by a distance of no more than 10 m. It is assumed that denser carbonate deposits at the seepage site can localize gas flows, thus reducing the volume of fluid discharge. It is shown that the specific fluid discharge in Laspi Bay is comparable with the flow from point seeps; the maximum fluid flow is only 3.5 times lower compared to the minimum recorded seep flow. Changes in hydrological parameters above the gas release point are significantly influenced by waves. The maximum change in salinity during measurements was 0.08%o, which indicates that there is no high-rate freshwater submarine discharge, which often accompanies seeps. Episodes of an abrupt decrease in oxygen content with an amplitude of 0.5 mg/L at night, which are not related to changes in water temperature and meteorological conditions, may be caused by the seepage of hydrogen sulfide in the bubble and fluid gases.

Significance A major uncertainty in the sources of atmospheric methane is the role of geologic seepage from petroleum-bearing sedimentary basins. Hydrocarbon seeps located onshore, shallow offshore, and coastal areas can play a major role. Methane released by deep ocean seeps typically does not reach the atmosphere. Here, we provide evidence for a single, large, and sudden expulsion of methane from a deep‐water reservoir during the Pliocene. We use geophysical evidence and fluid-flow modeling to estimate that this single event would have amounted to ∼10% of present‐day annual natural methane emissions. Although no ultraseepage events, such as this one, have been documented in modern times, the relatively common geologic circumstances of this type of event suggest that they are not exceptional., Geologic hydrocarbon seepage is considered to be the dominant natural source of atmospheric methane in terrestrial and shallow‐water areas; in deep‐water areas, in contrast, hydrocarbon seepage is expected to have no atmospheric impact because the gas is typically consumed throughout the water column. Here, we present evidence for a sudden expulsion of a reservoir‐size quantity of methane from a deep‐water seep during the Pliocene, resulting from natural reservoir overpressure. Combining three-dimensional seismic data, borehole data and fluid‐flow modeling, we estimate that 18–27 of the 23–31 Tg of methane released at the seafloor could have reached the atmosphere over 39–241 days. This emission is ∼10% and ∼28% of present‐day, annual natural and petroleum‐industry methane emissions, respectively. While no such ultraseepage events have been documented in modern times and their frequency is unknown, seismic data suggest they were not rare in the past and may potentially occur at present in critically pressurized reservoirs. This neglected phenomenon can influence decadal changes in atmospheric methane.

This 20-month study of a prairie hillslope seep system builds upon and extends the soil moisture record from a previous study conducted during the most extreme drought ever recorded in Texas. We se...

Two video time-lapse cameras (VTLCs) were deployed by a remotely operated underwater vehicle (ROV) to observe the temporal and spatial variability of a natural hydrocarbon seep at 1180 m depth in the Green Canyon 600 lease block, Gulf of Mexico. The VTLCs were positioned approximately 60 and 90 cm away from the vent, each recording 15 s video bursts at 30 frames per second, illuminated by a 2000 lumen (lm) LED lamp. One camera functioned for 2 weeks; the second camera recorded 568 video bursts at 6 h intervals from 3 September 2017 to 2 February 2018 (153 days). Over the campaign period, seepage from three vents along a 10 cm cluster shifted toward a new fault line with up to nine intermittent individual vents shifting along 20 cm. We developed a semisupervised algorithm using Mathematica and ImageJ routines to resolve the rise velocity and size of individual bubbles. The algorithm was applied to the last 30 frames of each video burst. Bubble characteristics were also analyzed in the videos recorded by the ROV camera. Processing VTLC records yielded a bubble size distribution comparable (5% deviation) to the ROV camera, while the rise velocities were found to be 12% smaller than the ROV data. Hydrocarbon flux estimated from VTLC data was also compared favorably (2% difference) with synoptic physical collections of hydrocarbons into an ROV-held funnel. The long-term measurements indicate that bubble rise velocity was weakly correlated to the discharge rate as well as to the cross-flow velocity.

Remote sensing techniques are widely used during petroleum exploration. However, limitations in spectral and spatial resolution mean that these techniques are used mainly to detect hydrocarbons eit...

Intrusive granite dykes and their weathered layers can have great effects on seepage into slopes and on their stability. However, few studies of this topic have been reported. Using the Zhonglincun landslide as an example, we investigate the impact of a dyke and its weathered layer on the formation mechanism of a rainfall-induced residual soil slope failure. The sliding mass of Zhonglincun landslide is mainly composed of residual soils of both tuff and an intrusive granite dyke. We used laboratory soil column tests to obtain rainfall infiltration characteristics of the two residual soils. The SEEP/W mode of Geo-studio software was then used to replicate the above soil column tests to back-analyze unsaturated hydraulic parameters of the two soils, which were later used to simulate seepage fields and stress-strain fields of the slope under Typhoon Tailim. The results indicate that the movement of rainwater in the residual soil of the granite dyke is much faster than that of the residual soil of the tuff. Rainwater infiltrates rapidly into the granite soil, and then flows laterally into the tuff residual soil, raising the groundwater table in the slope, especially near the contact between the two residual soils. This leads to a rapid increase in pore-water pressure and initiates the serious deformation of the landslide. The granite dyke and its residual soil have played a key role in the formation of Zhonglincun landslide.

Natural hydrocarbon seeps are ubiquitous along continental margins. Despite their significance, we lack a basic understanding of the long-term temporal variability of seep dynamics, including bubble size, rise velocity, composition, and upwelling and entrainment processes. The shortcoming makes it difficult to constrain the global estimates of oil and gas entering the marine environment. Here we report on a multi-method approach based on optical, acoustic, satellite remote sensing, and simulations, to connect the characteristics of a hydrocarbon seep in the Gulf of Mexico to its footprint on the sea surface. Using an in-situ camera, bubble dynamics at the source were measured every 6 h over 153 days and the integrated total hydrocarbon release volume was estimated as 53 m3. The vertical velocity was acoustically measured at 20 m above bed (mab) and found to be approximately 40% less than the dispersed-phase at the source, indicating that the measured values are reflecting the plume continuous-phase flow. Numerical simulations predict that the oily bubbles with diameters larger than 8 mm reach the surface with a small footprint, i.e. forming an oil slick origin, deflection of which with wind and surface current leads to the formation of an oil slick on the surface. Nineteen SAR images are used to estimate the oil seepage rate from GC600 for 2017 giving an average discharge of 14.4 cm3/s.

The Digboi oilfield located in the State of Assam, in the northeastern region of India, is one of the world’s oldest producing oilfields. Commercial oil production from this oilfield started with the drilling of Discovery Well No 1, in 1889. Natural seepages of hydrocarbons (crude oil) in the field are common and were responsible for its initial discovery. In the present investigation, the cultured hydrocarbon-utilizing bacterial diversity of a natural oil seep in Digboi oilfield was studied to gain a deeper insight into the microbial communities present in the crude oil seeps. The present study utilized relatively simple and traditionally used culture technique of vapor-phase transfer coupled with online open access bacterial identification software to study the microbial diversity of the surface macro-seepage of crude oil in the study area. The cultured hydrocarbon-utilizing bacterial diversity was revealed to be comprising of five dominant species, which belonged to five different genera of bacteria namely Clostridium, Providencia, Chromobacterium, Burkholderia and Pantoea. These results are important as the novel metabolic diversity of these culturable hydrocarbon-utilizing bacteria are being utilized for developing a wide array of biotechnological solutions such as bioremediation and biochemically enhanced oil recovery for the upstream Oil and Gas industry.

Understanding long-term trends in atmospheric concentrations of carbon dioxide (pCO2) has become increasingly relevant as modern concentrations surpass recent historic trends. One method for estimating past pCO2, the stable carbon isotopic fractionation associated with photosynthesis (Ɛp) has shown promise over the past several decades, in particular using species-specific biomarker lipids such as alkenones. Recently, the Ɛp of more general biomarker lipids, organic compounds derived from a multitude of species, have been applied to generate longer-spanning, more ubiquitous records than those of alkenones but the sensitivity of this proxy to changes in pCO2 has not been constrained in modern settings. Here, we test Ɛp using a variety of general biomarkers along a transect taken from a naturally occurring marine CO2 seep in Levante Bay of the Aeolian island of Vulcano in Italy. The studied general biomarkers, loliolide, cholesterol, and phytol, all show increasing depletion in 13C over the transect from the control site towards the seep, suggesting that CO2 exerts a strong control on isotopic fractionation in natural phytoplankton communities. The strongest shift in fractionation was seen in phytol, and pCO2 estimates derived from phytol confirm the utility of this biomarker as a proxy for pCO2 reconstruction.

The generation and migration processes, as well as the influence of secondary processes, on oil and natural gas accumulated in Lower Cretaceous–lower Miocene strata of the central part of the Ukrainian outer Carpathians are discussed. Type II and II/III kerogens from the Oligocene–lower Menilite beds of the Boryslav-Pokuttya nappe generated oil and natural gas mainly during the middle stage of the oil window. These hydrocarbons accumulated in the fields of the Boryslav-Pokuttya and Skiba nappes. Water washing is the dominant secondary process occurring in many accumulations, regardless of reservoir rock, whereas biodegradation is insignificant and is clearly evident only in natural gas from one seep in the abandoned Starunia ozocerite mine. All hydrocarbon gases are thermogenic and were generated from mixed organic matter containing various proportions of type II and III kerogens. Only one natural gas accumulation in the Pivnichna Dolyna field contains some microbial hydrocarbon contribution. Carbon dioxide mainly originated from thermogenic kerogen decarboxylation and sporadically from microbial processes. Molecular nitrogen was mainly generated during low-temperature thermal transformation of organic matter and could also partly originate from NH4-rich illites of the clayey facies of the Oligocene–lower Miocene Menilite beds. The integration of the geochemical data with geological setting and maturation history of source rocks enabled us to reconstruct hydrocarbon migration paths, revealing the complicated trap-filling process.

Two areas with cold methane seeps on the outer shelf of the Laptev Sea were studied by two interdisciplinary expeditions onboard the RV Akademik Mstislav Keldysh in August–September of 2017 and 2018. These fields lie in water between depths of 63 and 73 m, and in a region of growing interest to the international community. Characteristic features of the methane seeps were obtained, which include their distribution and appearance on the seabed based on acoustic anomalies and seafloor observations. The cold seeps are part of a domain striking in a SW–NE direction along the Laptev Sea Rift System, Khatanga–Lomonosov Fracture Zone, and the Gakkel Ridge junction, and its structure was determined by shallow faults on the outer shelf. These faults are related to subsidence of the outer shelf cutting the caprock formed by permafrost and gas hydrates. Faults serve as conduits for an intense bubble methane discharge at the seabed. Shallow-water methane seep fauna were described for the first time in the Siberian Arctic. The frenulate siboglinid tubeworm Oligobrachia haakonmosbiensis was among the dominant species of the methane seep communities. A newly discovered gastropod species Frigidalvania sp. was also found in abundance at the seeps as well as an ophiuroid Ophiocten sericeum. Significant differences were observed between benthic communities of the two seep fields and background fauna including integral community parameters and the presence/absence of certain species. Development of shallow methane seep communities in the Laptev Sea apparently is related to extremely oligotrophic conditions in this area.

Thirteen fossiliferous limestone deposits from Cenozoic strata in the Talara Basin in northern Peru are identified as ancient methane-seep deposits. Planktonic foraminifera and the existing stratig ...

Cold methane seeps were common in the Late Cretaceous Western Interior Seaway of North America. They provided a habitat for a diverse array of fauna including ammonites. Recent research has demonstrated that ammonites lived at these sites. However, it is still unknown if they hatched at the seeps or only arrived there later in ontogeny. To answer this question, we documented the abundance and size distribution of small specimens of Baculites and Hoploscaphites at eight seep sites in the Pierre Shale of South Dakota. The specimens of Hoploscaphites range from 0.8 to 8.1 mm in shell diameter, with most of them falling between 1 and 1.5 mm. The specimens of Baculites range from 0.7 to 19.2 mm in length, with most specimens falling between 6 and 8 mm. The small size and morphology of these specimens indicate that they are neanoconchs, that is, newly hatched individuals that lived for a short time after hatching. We also analyzed the isotope composition (δ13C and δ18O) of 12 small specimens of Baculites and one specimen of Hoploscaphites with excellent shell preservation from one seep deposit. The values of δ13C and δ18O range from -16.3 to -2.5‰ and -3.0 to -0.9‰, respectively. The values of δ18O translate into temperatures of 19–28°C, which are comparable to previous estimates of the temperatures of the Western Interior Seaway. The low values of δ13C suggest that the tiny animals incorporated carbon derived from anaerobic oxidation of 12C-enriched methane into their shells. Evidently, they must have lived in close proximity to seep fluids emerging at the sediment-water interface and the associated microbial food web. However, this may have contributed to their demise if they were exposed to elevated concentrations of H2S derived from the anaerobic oxidation of methane.

Surveys to locate and monitor bubble gas seeps in Lake Baikal have been conducted mainly using the active echolocation methods since the 2000s. This paper compares the active acoustic method with a newly developed optical and passive acoustic methods using the example of the shallow-water gas seep Istok in the Selenga shoal. The optical method is based on processing of underwater video records of ascending bubbles while the passive acoustic uses spectral analysis of gas jet noise recorded using a hydrophone. Optical and passive acoustic methods enables estimation of the bubble size distribution function, which is necessary for the calculation of the bubble gas flux. The latter can be evaluated from active echolocation or optical data. By applying these methods, their possibilities and limitations are revealed as well as benefits of their combined use and ways to improve their accuracy in future.

Sediments of the deep water Krasny Yar methane seep area of Lake Baikal contain channels of 1 cm in diameter and up to a depth of 150 cm that have a high water content and are characterized by higher oxidized and reduced conditions than the surrounding sediment. New data of lithological and geochemical studies, including the full anionic and cationic composition of pore waters, indicate that chemical flow at the sediment surface of the seep is heterogeneous in space with both areas of inflow of fluids and areas with outflow of fluids. We suggest that much of this flow is modulated by more complex hydrological processes that may include aqueous pumping driven by gas expulsion- and changes in the permeability of the conduits due to gas hydrate formation and dissociation. We discuss the seep output fluid chemistry and heat flow in relation to the above hydrological processes and propose a seep model where fluid and gas migrations act at different spatial scales partly favored by hydrate accumulation and the fresh water conditions of Lake Baikal.

The ground fissure of Shuanghuaishu in Shaanxi Province, China, is a tectonic ground fissure developed in the northern Loess Plateau of the Weihe Basin. Remarkably, it exhibits multiple activities under heavy rainfall conditions. To explore how heavy rainfall infiltration can induce ground fissures to reactivate, we conducted an in situ large-scale water immersion test on the ground fissure zone. Through measurement of soil moisture content and observation of subsidence and deformation of surface and soil layers at different depths before and after water immersion, we determined the variation law of soil moisture content and the humidification deformation of the ground fissure zone after rain infiltration. Results show that ground fissures destroy the structure of soil layers and form a certain width of influence zone, which allows surface water to seep through the fissure zone into the deep soil below the relative aquifuge. After water immersion, the deformation of the soil in the ground fissure zone is obviously larger than that in the non-fracture zone, the influence zone width of hanging wall of the ground fissure is larger than that of the footwall, and the influence range on the upper soil layer is larger than that on the lower soil layer.

Water purity was assessed at the site of a deep oil seepage near Cape Gorevoy Utes (Central Baikal). Polycyclic aromatic hydrocarbons (PAHs) and n-alkanes were determined in different types of oil-containing samples collected at this section of Lake Baikal. The set of studied samples included: (i) samples of water from the surface water layer; (ii) samples of water from different depths; (iii) oil on the water surface; (iv) oil from a sediment core. In the surface water layer and the water column, the total concentration of n-alkanes ranged from 0.2 to 5.3 µg/L and did not exceed the 0.1 maximum permissible concentration (MPCfish = 50 µg/L) established for hydrocarbons in water bodies of fishery importance. PAHs with carcinogenic properties were less than 0.1 ng/L. The total concentration of PAHs found in the water column did not exceed 110 ng/L; toxic equivalent (TEQ) values ranged from 0.001 to 0.110 ng/L. The distribution of petroleum hydrocarbons from the seepage site was limited, and water pollution was localised. The low level of water pollution is associated with natural mechanisms in the Baikal ecosystem. Microbiological community and phytoplankton make a decisive contribution to the purity of Baikal water, and oil fractionation during deep discharge contributes to the bioavailability of petroleum hydrocarbons.

Hill slope seep wetlands are ecologically and economically important ecosystems as they supply a variety of ecosystem services to society. In South Africa, livestock grazing is recognized as one of the most important disturbance factors changing the structure and function of hill slope seep wetlands. This study sought to investigate the potential effect of livestock grazing on the resilience and vulnerability of hillslope seep wetland vegetation cover using a trait‐based approach (TBA). Changes in vegetation cover were used as a surrogate for indicating grazing intensity. The degree of human disturbances was assessed using the Anthropogenic Activity Index. A TBA was developed using seven plant traits, resolved into 27 trait attributes. Based on the developed approach, plant species were grouped into vulnerable and resilient groups in relation to grazing pressure. It was then predicted that species belonging to the vulnerable group would be less dominant at the highly disturbed sites, as well as in the winter season when grazing pressure is at its peak. The approach developed enabled accurate predictions of the responses of hillslope plant species to grazing pressure seasonally, but spatially, only for the summer season. The predicted responses during the winter season across sites did not match the observed results, which could be attributed to the difficulty in species identification and accurate estimation of vegetation cover during winter. Overall, the approach developed here provides a general framework for applying the TBA and can thus be tested and applied elsewhere., The trait‐based approach used in this study enables the prediction of the effects of disturbance on vegetation patterns to guide conservation and management efforts. There is an urgent need to develop these approaches as the studied wetlands are disappearing at an increasing rate.

New quantitative and semiautomated methods for analyzing oil slick evolution using a time series of $L$ -band synthetic aperture radar (SAR) images with short repeat time are developed and explored. In this study, two methods that are complementary in terms of identifying temporal changes within an oil slick are presented. The two methods reflect two ways of evaluating the oil slicks. The first method identifies regions within the slick that show persistently high damping ratio (the contrast between clean sea and oil intensity), using higher damping values as a proxy for increasing oil thickness. This method also weights the age of the scenes as the algorithm incorporates new images. The second method outputs the short-term drift pattern and the changes in the damping ratios and copolarization ratios between two scenes, proxies for thickness, and emulsification. Both methods can aid in identifying regions of high priority for oil recovery. Due to the simplicity of the methods, they can be adapted to time-series data from different types of sensors, e.g., optical and SAR imagery. The methods are demonstrated on three $L$ -band uninhabited aerial vehicle SAR UAVSAR time series acquired in November 2016 over a persistent seep in the Mississippi Canyon Block 20 of the Gulf of Mexico. The results of the two methods clearly show the movement and the weathering of the oil as a function of both time and location.

This chapter explores how evidence of hydrocarbon seepage from charged petroleum reservoirs can be used in exploration. The discussion will cover microseepage onshore and macroseepage both onshore and offshore. Microseepage will focus on the direct hydrocarbon detection methods for soil gas and adsorber technologies. The macroseepage sections will concentrate on finding, sampling, analyzing, and interpreting data from seafloor seeps as part of a comprehensive offshore exploration program. It will also show how sea surface slicks can be used as more than just indicators of seep floor seeps in confirming the presence of petroleum systems.

The microbial key players at methane seeps are methanotrophic archaea and sulfate-reducing bacteria. They form spherical aggregates and jointly mediate the sulfate-dependent anaerobic oxidation of methane (SD–AOM: CH4 + SO42− → HCO3− + HS− + H2O), thereby inducing the precipitation of authigenic seep carbonates. While seep carbonates constitute valuable archives for molecular fossils of SD–AOM-mediating microbes, no microfossils have been identified as AOM aggregates to date. We report clustered spherical microstructures engulfed in 13C-depleted aragonite cement (δ13C values as low as −33‰) of Pleistocene seep carbonates. The clusters comprise Mg-calcite spheres between ∼5 µm (single spheres) and ∼30 µm (clusters) in diameter. Scanning and transmission electron microscopy revealed a porous nanocrystalline fabric in the core area of the spheres surrounded by one or two concentric layers of Mg-calcite crystals. In situ measured sphere δ13C values as low as −42‰ indicate that methane-derived carbon is the dominant carbon source. The size and concentric layering of the spheres resembles mineralized aggregates of natural anaerobic methanotrophic archaea (ANME) of the ANME-2 group surrounded by one or two layers of sulfate-reducing bacteria. Abundant carbonate-bound 13C-depleted lipid biomarkers of archaea and bacteria indicative of the ANME-2-Desulfosarcina/Desulfococcus consortium agree with SD–AOM-mediating microbes as critical agents of carbonate precipitation. Given the morphological resemblance, in concert with negative in situ δ13C values and abundant SD–AOM-diagnostic biomarkers, the clustered spheres likely represent fossils of SD–AOM-mediating microbes.

By remote sensing methods natural oil seeps and their sources in the southern part of the Caspian Sea off the coast of Iran and in the Barents Sea are studied. It is shown that with the help of a geoinformational approach and additional geological-geophysical information and bathymetric data, it is possible not only to determine their actual position at the bottom, but also to obtain information on their activity, e.g., frequency, volumes of emitted oil, and oil and gas deposits. In addition, this approach allows discovering new seep sources in various seas. It is concluded that the SAR data of the European Sentinel-1 satellites is an excellent material for monitoring and studying natural oil seeping through the observation of oil slicks floating on the sea surface.

Gas hydrates represent a huge reservoir of methane in marine sediments, prone to dissociation in response to environmental changes. There is consensus that past events of gas hydrate dissociation in the marine environment mainly occurred during periods of low sea‐level. Here, we report geochemical data for two meter‐thick layers of seep carbonate collected from a hydrate‐bearing drill core from ~800 m water depth in the northern South China Sea. The aragonite‐rich carbonates reveal positive δ18O values, confirming a genetic link with gas hydrate dissociation. Uranium‐thorium dating of seep carbonates indicates that gas hydrates at the study site dissociated between 133,300 and 112,700 yr BP, hence coinciding with the Last Interglacial (MIS 5e) sea level highstand. We put forward the concept that a climate‐driven increase in temperature was responsible for a period of pronounced gas hydrate dissociation. Plain Language Summary The gas hydrate reservoir is a dynamically changing system extremely susceptible to variations of seafloor temperature and pressure. Therefore, gas hydrate dissociation and subsequent methane seepage frequently occur during times of global climate change, especially during sea level lowstands with reduced seabed pressure. However, this conclusion was mainly based on dating of seep carbonates sampled from the seabed. As a consequence, one cannot exclude that previous results have been compromised by a sampling bias since seafloor samples are easier to collect. Authigenic seep carbonates from drill cores represent a continuous record of gas hydrate dynamics. Our uranium‐thorium dating of seep carbonate from drill cores provides a unique example of the effects of temperature and pressure on the stability of the hydrate system in the Dongsha area, northern South China Sea (SCS), during the last interglacial stage (MIS 5e, about 130,000 years BP). Representing the most similar and most contemporary analogue to the current interglacial, the study of a methane release event in the SCS during MIS 5e will shed light on the expected trend of methane release events in the future, while providing insight into the response of low latitude oceans to climate change.

In this study, we present a novel approach for assessing nearshore seepage atmospheric emissions through modeling of air quality station data, specifically a Gaussian plume inversion model. A total of 3 decades of air quality station meteorology and total hydrocarbon concentration, THC, data were analyzed to study emissions from the Coal Oil Point marine seep field offshore California. THC in the seep field directions was significantly elevated and Gaussian with respect to wind direction, θ. An inversion model of the seep field, θ-resolved anomaly, THC′(θ)-derived atmospheric emissions is given. The model inversion is for the far field, which was satisfied by gridding the sonar seepage and treating each grid cell as a separate Gaussian plume. This assumption was validated by offshore in situ data that showed major seep area plumes were Gaussian. Plume total carbon, TC (TC = THC + carbon dioxide, CO2, + carbon monoxide), 18 % was CO2 and 82 % was THC; 85 % of THC was CH4. These compositions were similar to the seabed composition, demonstrating efficient vertical plume transport of dissolved seep gases. Air samples also measured atmospheric alkane plume composition. The inversion model used observed winds and derived the 3-decade-average (1990–2021) field-wide atmospheric emissions of 83 400 ± 12 000 m3 THC d−1 (27 Gg THC yr−1 based on 19.6 g mol−1 for THC). Based on a 50 : 50 air-to-seawater partitioning, this implies seabed emissions of 167 000 m3 THC d−1. Based on atmospheric plume composition, C1–C6 alkane emissions were 19, 1.3, 2.5, 2.2, 1.1, and 0.15 Gg yr−1, respectively. The spatially averaged CH4 emissions over the ∼ 6.3 km2 of 25 × 25 m2 bins with sonar values above noise were 5.7 µM m−2 s−1. The approach can be extended to derive emissions from other dispersed sources such as landfills, industrial sites, or terrestrial seepage if source locations are constrained spatially.

Complex measurements of hydrological parameters and gas fluxes at the new methane seep recently discovered at Cape Fiolent (Crimean coast) were carried out. A lower values of water temperature T and concentration of dissolved oxygen O2 outer of the seepage area in comparison with the values above the gas point were registered. Episodes of an abrupt T and O2 increase with a subsequent decrease were noted. The estimation of the bubble gas fluxes was made by two different methods: video registration and trap method. The estimated flux was about 60 and 22.5 L/day out of entire seepage area respectively. High CH4 concentrations in sea-surface water above seep points were measured.

Oil spill is the term used to describe the leak of crude petroleum into the environment. Though, the natural seeped of crude oil into the environment is inevitable, the rate of anthropogenic leaching of oil into the ecosystem is alarming. It is released intentionally into the environment through bunkery, pipeline vandalism, pipeline sabotage, corrosion of crude oil pipeline, poor maintenance culture of oil facilities, leak from faulty equipment and sometime, from accidental discharge from tankers, vessels, and other logistic process. While the presence of crude oil on surface water, underground water and the terrestrial contaminates and pollutes them, the open combustion with the atmosphere has no economic, health and socio – economic value. The products of this now deadly mixture of chemical compound are feeds to climate change, acid rain and its associated effects on the ecosystem and many health defects in man. Because the impacts of oil spill remain many years after cleanup, the synergy of green innovations and the implementation of the millennium development goal alone will not do the trick, stakeholders should sit and review the fundamental cause of oil seep into the environment and close the gaps identified in this study in other to nip the cause of oil spill in the bud.