Search

The article in the journal "Frontiers in Earth Science" explores contemporary studies on cold seeps, hydrothermal vents, mud volcanoes, and related seafloor features. These features provide insights into deep processes that are typically inaccessible to scientists. The research emphasizes multidisciplinary approaches to studying seafloor fluid emissions, highlighting the importance of geologic, physical, chemical, and biological processes in these environments. The studies cover a wide range of topics, including microbial processes, fluid dynamics, mineralization, and the role of seafloor emissions in global biogeochemical cycles. [Extracted from the article]

Evidence suggests that sleep is a vital component of physical and health well-being. However, while sleep problems are present in individuals with mental health problems such as depression, it has not been clear whether these conditions are independent or whether they might be causally related. Indeed, if sleep or sleep disorders predispose or modify onset and outcomes of mental health issues, treatment of these factors could be explored as new mental health prevention or treatment options. The aim of this review was to examine in detail the bidirectional relationship between sleep, sleep disorders, and mental and physical health and well-being. It has considered the evidence that sleep architecture disruption, occurring through both quantity, quality, and timing of sleep as well as through the presence of sleep disorders may both influence mental health and well-being as well as be disrupted by both physical and mental health conditions. Also, the review has explored the effects of sleep disruption on mental health and performance through fatigue, mood, and vigilance. The review has considered the bidirectionality between sleep, sleep disorders, and mental health to examine how these may lead to or exacerbate mental health disorders such as affective, anxiety, autism, depressive and schizophrenia disorders but also considers how these conditions can affect sleep. The review highlights that poor sleep or the presence of a sleep disorder can increase the risks from mental health conditions such as suicidality. Furthermore, mental health conditions such as anxiety and worry can cause racing or repetitive thoughts that can keep an individual awake, leading to shortened sleep. It is important that sleep and sleep disorders are considered potential modifiable factors that could improve mental health outcomes. The important interconnect between both physical and mental health and sleep, in patient evaluations, also needs to be considered as these may affect treatment pathways and patient outcomes. Further, more robust and perspective research is required to establish the triad relationship of physical, mental health, and sleep.

Remote sensing of seeps, the release of gas (mainly methane) from the seabed, is an urgent problem. The importance of detecting seeps in the Arctic shelf zone is constantly increasing due to degradation of underwater permafrost and the release of gas hydrates. Gas bubbles scatter underwater sound and their corresponding resonance frequencies are in the kilohertz range for seeps observed in nature. A promising method for detecting and studying seeps is probing with underwater sound near the denoted resonance frequency. This corresponds to a decrease in the operating frequency with respect to the traditional method of studying high-frequency sonars, so the proposed method will be classified as low-frequency in this study. This method expands the study area due to the low sound attenuation in water and the high scattering level near bubble resonances. The scattering strength was estimated taking into account collective interaction (group effects) of bubbles. The possibility of using low-frequency hydroacoustic systems to detect seeps is demonstrated using the results of a full-scale experiment using a simulated bubble jet as an example. A data processing method for detecting nonstationary scatterers is proposed. [ABSTRACT FROM AUTHOR]

Deep‐sea chemosynthetic ecosystems are 'oases' of life powered by reducing geofluids, of which serpentinite‐hosted seeps are among the least studied. South Chamorro Seamount, a serpentine mud volcano on the Mariana Arc, has been known to host chemosynthesis‐based assemblages since 1996, but no detailed information on the fauna was published. Here, we revisited South Chamorro to characterise its biodiversity. We located two regions of chemosynthetic communities dominated by bathymodioline mussels, vesicomyid clams, and chaetopterid parchment worms: one on the northwestern flank ('Fryer Site') and one on the southern summit ('Summit Site'). We sampled a total of 20 species including 13 molluscs, five annelids, and two crustaceans – all present on the more active Summit Site but only a subset being found at Fryer Site. A mussel bed surrounding the Fryer Site was drilled by the Ocean Drilling Program in 2001 resulting in six holes, the deepest being 266 m (Hole 1200C). Cuttings ~50 cm deep still cover an approximately 60 m radius around Hole 1200C even 22 years later, and there is no sign of recovery. Low geofluid supply in serpentinite‐hosted seamounts may not allow decadal recovery of animal colonies, unlike a previous drilling site in an Okinawa Trough vent. [ABSTRACT FROM AUTHOR]

Evidence suggests that sleep is a vital component of physical and health well-being. However, while sleep problems are present in individuals with mental health problems such as depression, it has not been clear whether these conditions are independent or whether they might be causally related. Indeed, if sleep or sleep disorders predispose or modify onset and outcomes of mental health issues, treatment of these factors could be explored as new mental health prevention or treatment options. The aim of this review was to examine in detail the bidirectional relationship between sleep, sleep disorders, and mental and physical health and well-being. It has considered the evidence that sleep architecture disruption, occurring through both quantity, quality, and timing of sleep as well as through the presence of sleep disorders may both influence mental health and well-being as well as be disrupted by both physical and mental health conditions. Also, the review has explored the effects of sleep disruption on mental health and performance through fatigue, mood, and vigilance. The review has considered the bidirectionality between sleep, sleep disorders, and mental health to examine how these may lead to or exacerbate mental health disorders such as affective, anxiety, autism, depressive and schizophrenia disorders but also considers how these conditions can affect sleep. The review highlights that poor sleep or the presence of a sleep disorder can increase the risks from mental health conditions such as suicidality. Furthermore, mental health conditions such as anxiety and worry can cause racing or repetitive thoughts that can keep an individual awake, leading to shortened sleep. It is important that sleep and sleep disorders are considered potential modifiable factors that could improve mental health outcomes. The important interconnect between both physical and mental health and sleep, in patient evaluations, also needs to be considered as these may affect treatment pathways and patient outcomes. Further, more robust and perspective research is required to establish the triad relationship of physical, mental health, and sleep. [ABSTRACT FROM AUTHOR]

This study investigates the temporal variations in methane concentration and flare activity in the Hola trough (offshore Norway) during May 2018 and June 2022. Between these time periods, methane seep activity exhibits 3.5 times increase, as evidenced by hydroacoustic measurements. As the seep area in the Hola trough is constantly within the hydrate stability zone, the observed increase cannot be attributed to migration of its shallow boundary due to temperature increase. However, a combination of low tide conditions resulting in a lower sediment pore pressure and a bottom water temperature increase resulting in a lower methane solubility is likely to explain the increase in the number of seeps observed in June 2022. The hypothesis of tide influence is supported by data collected from a piezometer deployed and recovered during the cruise showing that the tidal effect was observed 3 m below the seafloor. Despite the numerous methane seeps detected, methane concentration and gas flow rates near the seafloor were low (<19 nM and <70 mL min−1, respectively) compared to other areas with methane seep activity. This is likely due to strong currents rapidly dispersing methane in the water column. Sub‐seafloor investigations identified pathways for gas migration in methane seep areas, influenced by topography. This study provides valuable insights into the temporal dynamics of methane concentrations, flare activity, and gas distribution in the Hola trough, contributing to our understanding of offshore methane dynamics in the region. Plain Language Summary: The Hola Trough, offshore Norway's Lofoten‐Vesterålen (LoVe) area, has been of interest for many years due to its rich marine life and potential oil and gas resources. There, coral mounds thrive around methane seepage. The LoVe observatory network monitors this unique environment. Using this observatory platform, associated data set and research expeditions at sea, the project EMAN7 (Environmental impact of Methane seepage and sub‐seabed characterization at LoVe‐Node 7) aims to understand the environmental impact of methane seepage as well as its spatio‐temporal variability. The comparison of methane seep activity during two summers with different environmental conditions revealed 3.5 times more seeps when a combination of warmer bottom water and low tide changes the sediment pore properties. A sensor recording subseafloor pore pressure and bottom temperature supports these findings. Sub‐seafloor investigations identified routes for gas migration in methane seep areas, influenced by topography. Key Points: A combination of warmer bottom water and low tide increases methane seeps 3.5 times by altering sediment gas solubility and pore pressureIntermittent seeps and strong oceanic currents explain the limited microbial mats and the low methane concentration in the water columnWe found sub‐seafloor pathways for gas migration in methane seep areas, influenced by topography [ABSTRACT FROM AUTHOR]

Chemosynthetic ecosystems powered by microbial primary production are rare 'hot spots' of biological activity in the deep‐sea characterized by dense aggregations of specially adapted animal species. Among settings where such systems have been found, serpentinite‐hosted seep systems supported by alkaline geofluid are particularly understudied with just a few known sites worldwide. Mariana Forearc hosts the world's only series of active serpentinite mud volcanoes, but seep communities have only been reported from South Chamorro Seamount where large bathymodioline mussels dominate. Here, we report the discovery of a serpentinite‐hosted seep on the conical summit of Asùt Tesoru Seamount, Mariana Forearc. Named the 'Big Blue Seep', this field features white, likely carbonate crusts inhabited by animals, under which fluid seepage could be seen. We confirm 16 animal species, including typical seep‐associated fauna such as Desbruyeresia gastropods and Acharax awning‐clams. This is surprising as previous research expeditions did not notice any sign of chemosynthesis‐based ecosystems on this seamount, although the community is indeed difficult to spot due to the lack of large‐bodied epifauna such as mussels. The Big Blue Seep is adjacent to three drill holes made by the International Ocean Discovery Program expedition 366 (Holes U1496A‐C), which may have impact on seepage. Our findings represent the second chemosynthesis‐based ecosystem associated with serpentinite mud volcanism, suggestive of further such communities on other Mariana Forearc mud volcanoes. [ABSTRACT FROM AUTHOR]

Identification of methane origins remains a challenging work as current diagnostic signals are often not sufficient to resolve individual formation and post‐formation processes. To address such a knowledge gap in a tectonically active and fragmented terrain, samples from mud volcanoes, gas seeps, and springs distributed along structural features onshore and offshore of Taiwan were analyzed for their isotopic compositions of methane, nitrogen, helium, dissolved inorganic carbon, CO2, and water. Our analyses yielded Δ13CH3D and Δ12CH2D2 values ranging between +1.9‰ and +7.8‰ and between +3.0‰ and +19.9‰, respectively. A portion of the samples were characterized by values that represent the thermodynamic equilibrium at temperatures of 99°–260°C. These temperature estimates, together with the bulk isotopic compositions and local geothermal gradients (25°–30°C/km), suggest that methane was formed by thermal maturation of organic matter at depths of 2–9 km below the land surface and channeled upward along faults. Other samples were found to deviate from equilibrium by varying degrees. Considering the geological background, helium isotopic ratios, and nitrogen isotopologue compositions, and methanogens detected at some sites, these gases are either abiotic in origin or a mixture of microbial and thermogenic sources. Regardless of whether the equilibrium of methane isotopologues was reached, few sites hosted by sedimentary formations were characterized by mantle‐like helium signatures, indicating decoupled origins and potential degassing of helium from the relic igneous source. Overall, these results suggest the extraction of methane and other gases from multiple depths from strata fragmented by fault displacement in an active orogenic belt. Plain Language Summary: Mud volcanoes and gas seeps are distributed primarily in active tectonic regimes and represent the surface expression of subsurface fracture networks. They provide rapid access to probing subsurface characteristics for the generations of methane, other gases, and water. Identifying the exact mechanisms of methane formation remains a challenging work due to the lack of diagnostic signals with sufficient resolving power. This study employed a wide range of isotopic tools to constrain the origins of gases and water from mud volcanoes and seeps in Taiwan, where dual subductions and associated arc‐continent collision between the Philippine Sea and Eurasian plates have enabled the plumbing of gases and water in accordance with structure development and stratum deformation. Our results reveal a spectrum of geochemical characteristics that point to diverse formation mechanisms and conditions. In particular, deeply sourced thermogenic methane (from depths of 2–9 km) appears to constitute a major gas component at most sites, and is mixed by various degrees with abiotic methane pertinent to igneous bodies emplaced during subduction/collision, or microbial methane generated at shallow depths. Overall, the results address the temporal and spatial variations in gas origins prone to terrain fragmentation and dynamic structural control associated with mountain building. Key Points: Mud volcanoes and gas seeps provide rapid access to probing subsurface fluid characteristics in tectonically active regionsThermogenic methane constitutes a major component of hydrocarbons and forms at temperatures of 99°–260°CA wide spectrum of geochemical characteristics indicates diverse formation mechanisms and conditions that constrain gas and water origins [ABSTRACT FROM AUTHOR]

Abstract Identification of methane origins remains a challenging work as current diagnostic signals are often not sufficient to resolve individual formation and post‐formation processes. To address such a knowledge gap in a tectonically active and fragmented terrain, samples from mud volcanoes, gas seeps, and springs distributed along structural features onshore and offshore of Taiwan were analyzed for their isotopic compositions of methane, nitrogen, helium, dissolved inorganic carbon, CO2, and water. Our analyses yielded Δ13CH3D and Δ12CH2D2 values ranging between +1.9‰ and +7.8‰ and between +3.0‰ and +19.9‰, respectively. A portion of the samples were characterized by values that represent the thermodynamic equilibrium at temperatures of 99°–260°C. These temperature estimates, together with the bulk isotopic compositions and local geothermal gradients (25°–30°C/km), suggest that methane was formed by thermal maturation of organic matter at depths of 2–9 km below the land surface and channeled upward along faults. Other samples were found to deviate from equilibrium by varying degrees. Considering the geological background, helium isotopic ratios, and nitrogen isotopologue compositions, and methanogens detected at some sites, these gases are either abiotic in origin or a mixture of microbial and thermogenic sources. Regardless of whether the equilibrium of methane isotopologues was reached, few sites hosted by sedimentary formations were characterized by mantle‐like helium signatures, indicating decoupled origins and potential degassing of helium from the relic igneous source. Overall, these results suggest the extraction of methane and other gases from multiple depths from strata fragmented by fault displacement in an active orogenic belt.

Copyright of Arxiu d'Etnografia de Catalunya is the property of Universitat Rovira I Virgili and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Groundwater discharge along channels can affect stream discharge, chemistry, and ecological communities. Although the spatial distribution of groundwater springs along wide rivers can be investigated by areal thermal infrared (TIR) remote sensing, this technique is difficult to apply to mapping at a high spatial resolution and under riparian tree canopies. We present a real‐time monitoring and postprocessing method of ground‐based TIR video for determining groundwater discharge sampling points and mapping the surface water temperature. We applied this method to mapping two headwater streams in Hokkaido, Japan, in the summer. The first site was a 1.3‐km‐long reach underlain by Pleistocene andesite lava. Almost all of the springs were colder and had a different chemistry compared to that of the stream water, which supports the usefulness of TIR monitoring for determining groundwater discharge zones. Video postprocessing showed that cold groundwater springs were spaced every ∼100 m, and their distribution did not follow the topography. At the second site, cold and warm springs were underlain by Holocene volcanic ash. The cold springs mainly seeped from hyporheic and riparian zones downstream, while warm springs were at the footslope. Some cold springs had much higher solute concentrations than the stream and warm springs, which suggests that the water temperature is useful for inferring sources of groundwater discharge. At this site, the video postprocessing could map not only the locations of the cold springs but also the spatial heterogeneity of the stream temperature associated with groundwater inputs. Key Points: Real‐time thermal imaging helps find suitable sampling points of groundwater discharge differing in chemistry from stream waterPostprocessing of thermal video can easily map springs with thermal anomalies and the spatial distribution of the stream temperatureThe water temperature of springs is useful for inferring their sources when multiple groundwater sources contribute to a stream [ABSTRACT FROM AUTHOR]

A new oil show, Zelenseep, was discovered on the eastern shore of Middle Baikal. It is characterized by natural gas discharge (seep) from the lake floor and by accumulation of oil (high- molecular-weight bitumen fraction) and gas hydrates in the top layer of the sediments. The gas in the sediments and gas hydrates is composed of 99% thermogenic methane. The carbon isotope composition (δ13(С–С1)) ranges from –48.1 to –48.8‰ for methane in the sediment and from –49.4 to –50.2‰ for that in the hydrates. Oil is not discharged into the water column. N-alkanes and isoprenoids are not found in the oil; polycyclic aromatic hydrocarbons are detected at the 1800– 2200 ppm level, including 50–90 ppm of rethene and 120–140 ppm of perylene. The perylene concentration evidences major transformation undergone by the oil on its migration path from the source. The presence of rethene in the oil is indicative of its continental origin, and that of biomarkers, hopanes, of its identity with the Baikal naphthenic-aromatic oils. The sediments of earlier Cenozoic age in Baikal Basin, occurring in its central deep-water part, were assigned to organic matter source. [ABSTRACT FROM AUTHOR]

Seabed methane gas emissions occur worldwide at cold seeps located along most continental margins. Fluxes of methane gas released from the seabed in the form of bubbles can be extremely variable even over short time intervals. Some factors controlling the variability are still poorly understood. Here, we report on the results of continuous long-term sonar monitoring of bubble emissions at a depth of 1,260 m on the Clayoquot Slope, northern Cascadia margin. With a total monitoring duration of 4 years and a sampling period of 1 h, this is by far the longest high temporal resolution monitoring of seabed methane gas release ever conducted. Our results provide evidence that the diurnal and semi-diurnal tides influence the timing of the onset and cessation of bubble emissions. However, gas emissions within the monitoring area are active more than 84% of the time, indicating that tides alone are not sufficient to make venting pause. We hypothesize that the gas fluxes are transient but generally sufficiently high to maintain ebullition independently of the tidally-induced bottom pressure variations. Results also show that the tides do not seem to modulate the vigor of active gas emissions.

A cell-averaged constant false alarm rate (CFAR) detector is described and applied to data collected with a multibeam echo sounder (MBES). The CFAR detector is designed specifically for transient targets observed with MBES, and operates under the assumption that background noise, including volume and seafloor reverberation, is locally stationary in time. This assumption, and the CFAR detector performance in general, was examined for data collected by a 30-kHz MBES operating in the Gulf of Mexico where the targets of interest were methane gas bubble plumes rising up from the seabed. Results with example data suggest that the CFAR detector was able to remove 99.1% of the MBES raw data while preserving the targets of interest. False detections appear randomly distributed throughout a single MBES ping, unlike the targets, and a within-ping target clustering algorithm was able to remove many of the false detections. In a single ping, an example is shown where the combined CFAR detector and a target cluster-size rule was able to reduce the number of false detections to 99.8% of the original data. The detector and cluster-size rules were applied to a sequence of approximately 400 pings, and two additional morphological rules based on the size and aspect ratio of the resulting target clusters were then applied to the detections to isolate the MBES backscatter intensity associated with gas bubbles. This combination of CFAR detector and simple morphological classification rules provides a useful way to detect gas bubble seeps or other transient targets. [ABSTRACT FROM AUTHOR]

The role of methane as a green-house gas is widely recognized and has sparked considerable efforts to quantify the contribution from natural methane sources including submarine seeps. A variety of techniques and approaches have been directed at quantifying methane fluxes from seeps from just below the sediment water interface all the way to the ocean atmosphere interface. However, there have been no systematic efforts to characterize the amount and distribution of dissolved methane around seeps. This is critical to understanding the fate of methane released from seeps and its role in the submarine environment. Here we summarize the findings of two field studies of the Bush Hill mud volcano (540 m water depth) located in the Gulf of Mexico. The studies were carried out using buoyancy driven gliders equipped with methane sensors for near real time in situ detection. One glider was equipped with an Acoustic Doppler Current Profiler (ADCP) for simultaneous measurement of currents and methane concentrations. Elevated methane concentrations in the water column were measured as far away as 2 km from the seep source and to a height of about 100 m above the seep. Maximum observed concentrations were ∼400 nM near the seep source and decreased away steadily in all directions from the source. Weak and variable currents result in nearly radially symmetric dispersal of methane from the source. The persistent presence of significant methane concentrations in the water column points to a persistent methane seepage at the seafloor, that has implications for helping stabilize exposed methane hydrates. Elevated methane concentrations in the water column, at considerable distances away from seeps potentially support a much larger methane-promoted biological system than is widely appreciated.

The occurrence and magnitude of natural fossil methane (CH4) emissions in the Arctic are poorly known. Emission of geologic CH4, a potent greenhouse gas, originating beneath permafrost is of particular interest due to the potential for positive feedback to climate warming, whereby accelerated permafrost thaw releases permafrost‐trapped CH4 in a future warmer climate. The development of through‐going taliks in Arctic lakes overlying hydrocarbon reservoirs is one mechanism of releasing geologically sourced, subpermafrost CH4. Here we use novel gas flux measurements, geophysical observations of the subsurface, shallow sediment coring, high‐resolution bathymetry measurements, and lake water chemistry measurements to produce a synoptic survey of the gas vent system in Esieh Lake, a northwest Alaska lake with exceedingly large geologic CH4 seep emissions. We find that microbially produced fossil CH4 is being vented though a narrow thaw conduit below Esieh Lake through pockmarks on the lake bottom. This is one of the highest flux geologic CH4 seep fields known in the terrestrial environment and potentially the highest flux single methane seep. The poleward retreat of continuous permafrost may have implications for more subcap CH4 release with increased permafrost thaw. [ABSTRACT FROM AUTHOR]

Natural seeps occur at the seafloor as loci of fluid flow where the flux of chemical compounds into the ocean supports unique biologic communities and provides access to proxy samples of deep subsurface processes. Cold seeps accomplish this with minimal heat flux. While individual expertize is applied to locate seeps, such knowledge is nowhere consolidated in the literature, nor are there explicit approaches for identifying specific seep types to address discrete scientific questions. Moreover, autonomous exploration for seeps lacks any clear framework for efficient seep identification and classification. To address these shortcomings, we developed a Ladder of Seeps applied within new decision-assistance algorithms (Spock) to assist in seep exploration on the Costa Rica margin during the R/V Falkor 181210 cruise in December, 2018. This Ladder of Seeps [derived from analogous astrobiology criteria proposed by Neveu et al. (2018)] was used to help guide human and computer decision processes for ROV mission planning. The Ladder of Seeps provides a methodical query structure to identify what information is required to confirm a seep either: 1) supports seafloor life under extreme conditions, 2) supports that community with active seepage (possible fluid sample), or 3) taps fluids that reflect deep, subsurface geologic processes, but the top rung may be modified to address other scientific questions. Moreover, this framework allows us to identify higher likelihood seep targets based on existing incomplete or easily acquired data, including MBES (Multi-beam echo sounder) water column data. The Ladder of Seeps framework is based on information about the instruments used to collect seep information (e.g., are seeps detectable by the instrument with little chance of false positives?) and contextual criteria about the environment in which the data are collected (e.g., temporal variability of seep flux). Finally, the assembled data are considered in light of a Last-Resort interpretation, which is only satisfied once all other plausible data interpretations are excluded by observation. When coupled with decision-making algorithms that incorporate expert opinion with data acquired during the Costa Rica experiment, the Ladder of Seeps proved useful for identifying seeps with deep-sourced fluids, as evidenced by results of geochemistry analyses performed following the expedition.

Diagenetically formed magnetic minerals at marine methane seep sites are potential archive of past fluid flow and could provide important constraints on the evolution of past methane seepage dynamics and gas hydrate formation over geologic time. In this study, we carried out integrated rock magnetic, and mineralogical analyses, supported by electron microscope observations, on a seep impacted sediment core to unravel the linkage between greigite magnetism, methane seepage dynamics, and evolution of shallow gas hydrate system in the K-G basin. Three sediment magnetic zones (MZ-1, MZ-2, and MZ-3) have been identified based on the down-core variations in rock magnetic properties. Two events of intense methane seepage are identified. Repeated occurences of authigenic carbonates throughout the core indicate the episodic intensification of anaerobic oxidation of methane (AOM) at the studied site. Marked depletion in magnetic susceptibility manifested by the presence of chemosynthetic shells (Calyptogena Sp.), methane-derived authigenic carbonates, and abundant pyrite grains provide evidences on intense methane seepage events at this site. Fracture-controlled fluid transport supported the formation of gas hydrates (distributed and massive) at this site. Three greigite bearing sediment intervals (G1, G2, G3) within the magnetically depleted zone (MZ-2) are probably the paleo-gas hydrate (distributed-type vein filling) intervals. A strong linkage among clay content, formation of veined hydrate deposits, precipitation of authigenic carbonates and greigite preservation is evident. Hydrate crystallizes within faults/fractures formed as the methane gas migrates through the gas hydrate stability zone (GHSZ). Formation of authigenic carbonate layers coupled with clay deposits restricted the upward migrating methane, which led to the formation of distributed-type vein filling hydrate deposits. A closed system created by veined hydrates trapped the sulfide and limited its availability thereby, causing arrestation of pyritization and favored the formation and preservation of greigite in G1, G2, G3.

Sleep problems in children with autism spectrum disorder are prevalent and persistent but also treatable. Little is known about how and why parents of such children seek help for sleep disturbance. Via an online survey (n = 244 respondents), we gathered information about parents' attributions about children's sleep problems and beliefs about causes and on sources of information about, and their decisions regarding, help-seeking. Eighty-two percent of parents reported seeking some kind of help for their child's sleep disturbance, and the average parent had tried six different treatment strategies, most commonly medical. Alignment of parents' treatment choices with empirical evidence about treatment efficacy was poor, but belief in effectiveness was closely related to frequency of use of a treatment. In a Principal Components Analysis, parental attributions loaded on two factors: one which suggests the sleep problems are viewed as intrinsic to autism and stable (factor one) and the other as located within the child, stable, and treatment resistant (factor two). These findings have important implications for parental education and clinical practice in the treatment of sleep problems in children with autism spectrum disorder. Sleep problems are commonly reported among parents of children with autism spectrum disorder (ASD). Without effective treatment, such problems are unlikely to resolve. To date, we know very little about how and why parents of children with ASD seek help for sleep disturbance. Via an online survey, we gathered information about how parents make sense of their children's sleep problems, beliefs about their causes, sources of information, and help-seeking behavior. The analysis of responses from 244 parents revealed that parents commonly view sleep problems (a) as a consequence of their child's ASD, and unlikely to change over time (stable), and (b) as located within the child (intrinsic), stable over time, and difficult to treat. Despite this, parents also rated sleep problems as being important to treat. Eighty-two percent of parents surveyed reported seeking some kind of help for their child's sleep disturbance, and the average parent had tried six different treatment strategies, most commonly medical approaches (e.g. melatonin). The alignment between parents' treatment choices and those strategies that are supported by research was poor, but belief in the effectiveness of treatments was closely related to how often the treatment was used. These findings have important implications for parental education and clinical practice in the treatment of sleep problems in children with ASD. [ABSTRACT FROM AUTHOR]

Garland Seep is a Southern Appalachian fen that supports a population of federally endangered green pitcher plants (Sarracenia oreophila). The wetland is underlain by clayey stream deposits above fractured bedrock, is located at the base of a mountain slope, and is fed by groundwater that originates as recharge on the adjacent hillslope. Groundwater wells were installed following a hydrologic restoration in the mid-1990s and have been monitored at varying frequencies since that time. The 20+ year record provides evidence that Garland Seep can be classified as a "hypocrene fen," in which spring flow rarely reaches the ground surface because of low discharge rates and high evapotranspiration (ET). In general, water-level fluctuations followed seasonal ET patterns, with higher water levels in the winter and early spring (when ET is low) and lower levels in the summer and fall. During wetter years, the water table remained near the ground surface for much of the year, with the clay layer underlying the site retaining moisture even after water levels had dropped. The "clay wetting" period was shorter during dryer years and corresponded with a reduction in the number of pitcher plant clumps observed at the site. In addition to the geologic and climatic controls on hydrology, previous landowners used fire to maintain open space for grazing, and The Nature Conservancy has continued the practice to combat woody vegetation and to open the canopy. Prescribed burns reduce ET (at least initially), cause a rise in water levels, and have helped maintain a thriving Sarracenia population. [ABSTRACT FROM AUTHOR]

Introduction: Neck circumference (NC) is one of the parameters to be associated with obstructive sleep apnea (OSA). However, there is lack of research data reflecting our local population with regard to the size of NC in relation to the severity of OSA. Aim: The primary goal of this study was to investigate the association of NC with OSA and to compare NC with other parameters as a predictor of the severity of OSA, among local population. This future reliable parameter can be used in front line clinics as to guide the referral to the tertiary center. Material and methods: This was a prospective study conducted upon 120 OSA patients, aged within 18-55 years, who underwent overnight polysomnography with apnea/hypopnea index more than 5 and met all the inclusion criteria. All patients completed the Epworth sleepiness scale questionnaire while all the parameter measurement including height, weight, body mass index and NC were documented. Results and discussion: A Pearson correlation analysis showed NC was significantly associated with OSA (r = 0.495, P < 0.001) while multiple linear regression model displayed an association between NC and lowest SpO2 desaturation during sleep (LSAT) as predictors of OSA severity (P < 0.001). Mean value of NC also significantly higher among severe OSA compared to mild OSA (42.7 ± 0.9 cm vs. 39.0 ± 1.3 cm; P < 0.001). Conclusions: NC was significantly associated with OSA and both NC and LSAT were significantly correlated as predictors of OSA severity. [ABSTRACT FROM AUTHOR]

[Display omitted] • Phylogenomic data from six species representing three deep-water patellogastropod families was obtained. • Mitogenome recovers monophyly of eight families in most trees and consistency in the genus-level relationships; phylogenomics recovers a robust family-level topology. • Deep-water families are monophyletic, indicating a single colonisation around the Jurassic. • A lack of significant correlation between genome size and habitat depth. Patellogastropoda, the true limpets, is a major group of gastropods widely distributed in marine habitats from the intertidal to deep sea. Though important for understanding their evolutionary radiation, the phylogenetic relationships among the patellogastropod families have always been challenging to reconstruct, with contradictory results likely due to insufficient sampling. Here, we obtained mitogenomic and phylogenomic data (transcriptomic or genomic) from six species representing the three predominantly deep-water patellogastropod families: Lepetidae, Neolepetopsidae, and Pectinodontidae. By using various phylogenetic methods, we show that mitogenome phylogeny recovers monophyly of eight families in most of the trees, though the relationships among families remain contentious. Meanwhile, a more robust family-level topology consistent with morphology was achieved by phylogenomics. This also reveals that these mainly deep-water families are monophyletic, suggesting a single colonisation of the deep water around the Jurassic. We also found a lack of significant correlation between genome size and habitat depth, despite some deep-water species exhibiting larger genome sizes. Our phylogenomic tree provides a stable phylogenetic backbone for Patellogastropoda that includes seven of the nine recognized families and paves the way for future evolutionary analyses in this major group of molluscs. [ABSTRACT FROM AUTHOR]

The relevance of the research is caused by the need to develop a scientifically based approach to quantitative estimation of bubble transfer of methane and other gases based on acoustic techniques, which allow reliable estimate of methane flow from the bubble unloading areas by sound locators and submarine sonars. The main aim of the research is to investigate the possible application of an acoustical technique based on acoustic scattering in bubble plumes vs the acoustical technique based on calibration which was applied to quantify in situ sonar observations; to show that both techniques can be used for a quantification of methane ebullition in the bottom-water column system. Objects: gas flares or seeps – the emanations of gas in the form of rising bubbles from the seabottom, which form stable regions of their increased concentration in the water column. Methods: modification of acoustical techniques based on acoustic scattering in bubble plumes and on ist calibration which was applied by authors to quantify in situ single sonar observations. Results. We demonstrate a first attempt to use acoustical techniques based on (1) acoustic scattering in bubble plumes vs acoustical technique based on (2) calibration which was applied to quantify in situ sonar observations. It has been shown that both techniques can be used for a quatitative express-evaluation of methane ebullition in the bottom-water system in any aquatic ecosystem including seas, lakes, and rivers, while the first acoustical technique gives the bubble efflux values ~20 % lower then the second acoustical technique.

Dolomite rarely occurs in modern marine environments, while it is ubiquitous in the geological record. This apparent contradiction made the formation mechanism of dolomite a long-standing problem haunting sedimentologists. However, dolomite is a constituent of many modern seep carbonates, providing an opportunity to investigate the conditions favoring dolomite formation at low temperatures in the shallow subseafloor. This study reports the petrology, mineralogy, carbon and oxygen stable isotopic compositions, as well as sulfur isotopic compositions of both carbonate-associated sulfate (CAS) and chromium reducible sulfur (CRS) of a set of dolomite-bearing carbonates from two seep sites (GC140 and GB382) on the northern slope of the Gulf of Mexico. The δ13C values of carbonates vary from −50.0‰ to 3.2‰ (V-PDB), confirming that carbonate minerals mostly resulted from methane oxidation. The corresponding δ18O values range from 2.6‰ to 5.9‰ (V-PDB), reflecting formation close to equilibrium with seawater composition. All carbonate samples with dolomite show similar petrologies and lack skeletal remains of seep-dwelling metazoans. The homogenous texture of microcrystalline dolomite agrees with its formation in the shallow subseafloor. Dolomite-bearing samples reveal δ18O CAS /δ34S CAS slopes of 0.425 and 0.435 for the two study sites, respectively. Such high slopes are significantly different from the smaller slopes of seep carbonates consisting of calcite from Gulf of Mexico seeps, suggesting low overall sulfate reduction rates during dolomite formation. This explanation is also supported by relatively high δ34S CRS values ranging from −29.4‰ to 19.0‰ (V-CDT) and the positive correlation of these values with dolomite contents. Interestingly, an approximately stoichiometric dolomite sample yielded the most positive δ34S CRS value, indicating a formation environment typified by low replenishment of seawater sulfate at a supposedly relatively deep sulfate methane transition zone (SMTZ). Overall, these results confirm that dolomite formation is facilitated where the SMTZ is situated at relatively great depth, where sulfate reduction rates are slowed down due to the buildup of high contents of dissolved sulfide and low seawater sulfate replenishment. • CAS and CRS geochemistry were applied to dolomite-bearing seep carbonates. • Low CAS contents confirm dolomite formed at greater depth during sulfate reduction. • High δ18O CAS /δ34S CAS slope suggests low sulfate reduction rate during dolomite formation. • Elevated δ34S CRS values indicate low replenishment of seawater sulfate. • Understanding dolomite formation at seeps helps in to disentangle the "dolomite problem". [ABSTRACT FROM AUTHOR]

As bottom water warms, destabilisation of gas hydrates may increase the extent of methane-rich sediments. The authors present an assessment of organic carbon processing by the benthic community in methane-rich sediments, including one of the first investigations of inorganic C fixation in a non-hydrothermal vent setting. This topic was previously poorly studied, and there is much need to fill the gaps in knowledge of such ecosystems. The authors hypothesized that benthic C fixation would occur, and that a high biomass macrofaunal community would play a substantial role in organic C cycling. Experiments were conducted at a 257 m deep site off South Georgia. Sediment cores were amended with 13C and 15N labelled algal detritus, or 13C labelled bicarbonate solution. In the bicarbonate experiment, labelling of bacteria-specific phospholipid fatty acids provided direct evidence of benthic C fixation, with transfer of fixed C to macrofauna and dissolved organic carbon (DOC). In the algae experiment, macrofauna played an active role in organic carbon cycling. Compared to similar experiments, low temperature supressed the rates of community respiration and macrofaunal C uptake. While benthic C fixation occurred, the biological processing of organic carbon was dominantly controlled by low temperature and high photic zone productivity. [ABSTRACT FROM AUTHOR]

This investigation concerns to find a new equation for computing the quantity of seepage through homogenous earth dam with horizontal toe drain. For this purpose the computer program SEEP/W (which is a sub-program of Geo-Studio) was used. The SEEP/W runs were carried out with three different downstream slopes of the dam, three different upstream slopes, three variable horizontal toe drain lengths, three different free boards, three different top widths and three different heights of the dam. For each run the quantity of seepage was determined. The results show that the seepage discharge increased with increasing upstream slope, downstream slope, upstream reservoir water depth and length of horizontal toe drain. Also, the results show that the seepage discharges decreased with increasing the top width of the dam and the height of the free board. Using SEEP/W results with helping a dimensional analysis theory, a new easy and reliable empirical equation for computing seepage discharge through homogenous earth dams with horizontal toe drain was developed. The analysis of the results by Artificial Neural Network (ANN) shows that the length of horizontal toe drain (L) is the more geometrical variable effect on the seepage discharge, while the upstream slope (tanθ) of the earth dam has a little effect.

This research concerns to study the quantity of seepage running downward from triangular open channel with lining and unlining using computer program SEEP/W (which is a sub-program of Geo-Studio). Using SEEP/W experiments two groups were carried out with three different downstream slopes of triangular open channel, three different upstream slopes, three variable free board, three different height of triangular open channel, for first group using three different permeability for soil around the triangular open channel and for second group using three different permeability for lining layer and for soil around triangular open channel. For each run the quantity of seepage were determined. Dimensional analysis was used with helping of the theoretical results to develop empirical equations in order to determine the quantity of seepage running downward the triangular open channel for lining and unlining. Also, Verify the SEEP/W results with analytical method ofVedernikov’s equation. Results show good agreement for triangular open channel unlining layer.

Highlights • Seep carbonates are hotsted in Miocene marine mudstone of the Kuohsing area, Taiwan. • Carbon isotope signals were strongly altered, but REE compositions remain unaffected. • Negative δ13C of −47.6‰ was recognized as a near-primary isotopic signature. • Carbonates show MREE enrichment, no La and Ce anomalies, and supra-chondritic Y/Ho. • Carbonates were formed in reducing seep fluids with limited admixture of seawater. Abstract Hydrocarbon-seep carbonates were discovered to be hosted within Miocene marine mudstone in the central Western Foothills near the Kuohsing area, Central Taiwan. Here, we present field observations, petrography, mineralogy, stable carbon isotope data, as well as rare earth element compositions. We evaluate the role of diagenetic alteration on the Kuohsing seep carbonates and constrain their fluid sources and formation conditions. Four main morphologies in the field were observed, including cylindrical columns, massive forms, lenticular nodules, and stratiform bodies. Petrographically, the carbonates are predominantly composed of partially recrystallized calcite and dolomite, with abundant amounts of biogenic detritus, pyrite aggregations and unidentified filaments. Isotopic analyses show that carbon isotope values inversely vary with oxygen isotope values, indicating substantial modification of the carbon isotope compositions of the carbonates by diagenetic processes. Extremely negative δ13C values as low as −47.6‰ recognized as a near-primary isotopic signature recorded in the carbonates, an end member of the trend, reveals that methane was incorporated during the carbonate precipitation. On the other hand, the carbonates have well preserved primary REE compositions, exhibiting MREE enrichment, no La and Ce anomalies, and supra-chondritic Y/Ho ratios. These REE patterns suggest that the Kuohsing authigenic carbonates were precipitated from reducing seep fluids with limited admixture of seawater. [ABSTRACT FROM AUTHOR]

Though geochemically and microbially well-defined, the phylogeographic data of microbial symbionts in these highly productive vent and seep systems require a closer examination and synthesis. QIIME analysis of 16S rDNA of bacterial associates of major fauna from 1995 to 2015 was thus undertaken to examine phylogeography of their microbial symbionts along with host specificity. While phylotypes were generally unrelated, bivalve Calyptogena exhibited vertical transmission sharing similar symbionts in geographically separated geosystems. Different species of tubeworms possessed identical symbionts through horizontal acquisition at geographically distinct Guaymas basin vent and the Arctic seep. Vents were more versatile with both mobile and sessile fauna hosting ecto- and endo-symbionts. Comparatively, seeps were more specialized with sessile animal hosts with endosymbionts. C-fixation rate measurements are still scanty for sediments, bedrocks and serpentine systems; vent, seep, anoxic and oxic basins were shown to fix up to 22, 325, 96, and 37,400 g C m−3 y−1, respectively. Estimation of chemosynthetic primary production rates in chemoautotrophic ecosystems could endeavor to improve existing biogeographic models by coupling volcanism and plate-tectonics to global climate and phylogeography. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the spatial distribution and signal intensity changes following spinal cord activation in patients with spinal cord injury.Methods: This study used spinal functional magnetic resonance imaging (fMRI) based on signal enhancement by extra-vascular water protons (SEEP) to assess elicited responses during subcutaneous electrical stimulation at the right elbow and right thumb in the cervical spinal cord.Results: Seven healthy volunteers and seven patients with cervical spinal cord injury (SCI) were included in this study. Significant functional activation was observed mainly in the right side of the spinal cord at the level of the C5-C6 cervical vertebra in both the axial and sagittal planes. A higher percentage of signal changes (4.66 ± 2.08 % in injured subjects vs. 2.78 ± 1.66 % in normal) and more average activation voxels (4.69 ± 2.59 in injured subjects vs. 2.56 ± 1.13 in normal subject) in axial plane at the C5-C6 cervical vertebra with a statistically significant difference. The same trends were observed in the sagittal plane with higher percentage of signal changes and more average activation voxels, though no statistically significant difference compared with the control group.Conclusions: Spinal SEEP fMRI is a powerful noninvasive method for the study of local neuronal activation in the human spinal cord, which may be of clinical value for evaluating the effectiveness of interventions aimed at promoting recovery of function using electrical stimulation. [ABSTRACT FROM AUTHOR]

Studies of deep-sea benthic communities have largely focused on particular (macro) habitats in isolation, with few studies considering multiple habitats simultaneously in a comparable manner. Compared to mega-epifauna and macrofauna, much less is known about habitat-related variation in meiofaunal community attributes (abundance, diversity and community structure). Here, we investigated meiofaunal community attributes in slope, canyon, seamount, and seep habitats in two regions on the continental slope of New Zealand (Hikurangi Margin and Bay of Plenty) at four water depths (700, 1,000, 1,200 and 1,500 m). We found that patterns were not the same for each community attribute. Significant differences in abundance were consistent across regions, habitats, water and sediment depths, while diversity and community structure only differed between sediment depths. Abundance was higher in canyon and seep habitats compared with other habitats, while between sediment layer, abundance and diversity were higher at the sediment surface. Our findings suggest that meiofaunal community attributes are affected by environmental factors that operate on micro- (cm) to meso- (0.1–10 km), and regional scales (> 100 km). We also found a weak, but significant, correlation between trawling intensity and surface sediment diversity. Overall, our results indicate that variability in meiofaunal communities was greater at small scale than at habitat or regional scale. These findings provide new insights into the factors controlling meiofauna in these deep-sea habitats and their potential vulnerability to anthropogenic activities.

• Low-boiling metals are prone to SEEP (physical factor) when mixed with decomposable inertants. • The mixed dust of high-boiling metals with strong stable inertants is less likely to lead SEEP. • Exothermic reaction of metals with inertants is a chemical factor that leads to SEEP. • Combustion of gases from decomposition of inertants is another chemical factor. Adding solid inertants to metal dust is an effective means of reducing the risk of dust fires and explosions. However, inertants that can effectively suppress the metal dust deflagration could somehow violently enhance the fire hazard of the same metal dust layer. This severe risk has not been well recognized and discussed in depth. To investigate the physical and chemical factors that cause the SEEP phenomenon, flame propagation experiments on mixed dust layers were performed using three common metal dusts (Mg, micro Ti, nano Ti) and five commonly used inertants (NH 4 H 2 PO 4 , NaHCO 3 , CaCO 3 , SiO 2 , CaO). The results indicate that the physical factors were the vaporization of metal dust and the destruction of the oxide layer by the gas from the decomposition of inertants. The chemical factors behind SEEP were the exothermic chemical reaction of metal dust with inertants, and the combustion of the gases released by the decomposition of inertants. Both factors significantly increased the severity of a fire in the dust layers, and in some cases, the chemical factors increased the likelihood of an explosion. Regardless of physical or chemical factors, the mass percentage of inertants in the mixed dust layers that lead to SEEP has a relatively wide range. Therefore, research on the use of solid inertant technology to prevent or mitigate dust explosions should fully consider the physicochemical properties of metal dust. The results are supposed to be used as a comprehensive guide for selecting suitable inertants for metal dust to prevent fire and explosion incidents. [ABSTRACT FROM AUTHOR]

The objective of this study was to compare to each other the methods currently recommended by the American Academy of Sleep Medicine ( AASM) to measure snoring: an acoustic sensor, a piezoelectric sensor and a nasal pressure transducer (cannula). Ten subjects reporting habitual snoring were included in the study, performed at Landspitali-University Hospital, Iceland. Snoring was assessed by listening to the air medium microphone located on a patient's chest, compared to listening to two overhead air medium microphones (stereo) and manual scoring of a piezoelectric sensor and nasal cannula vibrations. The chest audio picked up the highest number of snore events of the different snore sensors. The sensitivity and positive predictive value of scoring snore events from the different sensors was compared to the chest audio: overhead audio (0.78, 0.98), cannula (0.55, 0.67) and piezoelectric sensor (0.78, 0.92), respectively. The chest audio was capable of detecting snore events with lower volume and higher fundamental frequency than the other sensors. The 200 Hz sampling rate of the cannula and piezoelectric sensor was one of their limitations for detecting snore events. The different snore sensors do not measure snore events in the same manner. This lack of consistency will affect future research on the clinical significance of snoring. Standardization of objective snore measurements is therefore needed. Based on this paper, snore measurements should be audio-based and the use of the cannula as a snore sensor be discontinued, but the piezoelectric sensor could possibly be modified for improvement. [ABSTRACT FROM AUTHOR]

Groundwater seeps are characteristic hydrological and ecological features of many landscapes, yet their hydrology remains poorly understood. Here, we provide the first detailed measurements of near-surface soil moisture dynamics in a Muhly grass ( Muhlenbergia riverchonii) seep system developed in soils over interbedded limestone and marl. These features are characteristic of, and prevalent within, the North Central Texas Grand Prairie Ecoregion. The data were collected during the most severe drought in Texas history. We quantify the spatial-temporal variability of volumetric soil moisture (θv) and matric potential (ψm) along a slope containing a seep upslope, with a view to assessing whether the seep qualifies as an isolated wetland under the Environmental Protection Agency's proposed changes to Section 404 legislation for wetland determination. We found the Muhly seep to consistently be the wettest portion of the hillslope, with a statistically distinguishable drying trend downslope into a barrens environment with the thinnest soils. ψm within the seep remained at or above field capacity (θfc) 37% of the time during pre-drought conditions and was at all times wetter than lower sections of the slope between the seep and barrens. The seep responded rapidly to rainfall and remained at or close to saturation for 5 to 7 days following storm events. Saturation is controlled by fractured limestone sitting on top of a subsurface marl layer, resulting in water easily percolating through the limestone, ponding, and then moving laterally as interflow above the marl. Although the wetland characteristics of Muhly seeps could not be conclusively assessed because of extreme drought conditions, our data suggest that under normal rainfall conditions, these systems might likely qualify as isolated wetlands. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Coastal upwelling systems are important marine sources of methane (CH 4 ) and nitrous-oxide (N 2 O). Current understanding of the controls on CH 4 and N 2 O distributions in these coastal waters is restricted by limited data availability. We present the first multi-year measurements of CH 4 and N 2 O distributions from the seasonally upwelling shelf waters of British Columbia, Canada, a coastal end-member of the north Pacific oxygen minimum zone (OMZ). Our data show significant seasonal differences in CH 4 and N 2 O distributions and fluxes driven predominantly by upwelling. Methane is supplied to the water column primarily from sediments (especially near methane seeps), and is transported to the surface mixed layer by upwelling. A positive correlation between CH 4 concentrations and salinity indicates limited inputs from Fraser River estuary waters to the study site. Shelf waters receive N 2 O from a deep, off-shelf N 2 O maximum in the OMZ core, and from nitrification in the water column and possibly sediments. Both the physical transport of N 2 O and its apparent in situ production are enhanced under upwelling conditions. N 2 O yields from nitrification, estimated from changes in N 2 O and nitrate + nitrite (NO 3 − + NO 2 − ) along isopycnals, ranged from 0.04–0.49%, with the highest values observed under low ambient O 2 concentrations. Sea–air fluxes ranged from − 4.5–21.9 μmol m − 2 day − 1 for N 2 O and 2.5–34.1 μmol m − 2 day − 1 for CH 4 , with the highest surface fluxes observed following summer upwelling over the broad continental shelf of southern Vancouver Island. Our results provide new insight into the factors driving spatial and inter-annual variability in marine CH 4 and N 2 O in high productivity coastal upwelling regions. Continued time-series measurements will be invaluable in understanding the longer-term impacts of climate-driven variability on marine biogeochemical cycles in these dynamic near-shore waters. [ABSTRACT FROM AUTHOR]

The taxonomy of living species in the chemosymbiotic bivalve family Solemyidae from New Zealand is reviewed on the basis of external anatomy and shell morphology. Five species are recognised of which three,Solemya calypson. sp.,S. marshallin. sp. andS. puatan. sp., are newly described, the former from a hydrothermal vent system, the latter two from the ambient environment. A lectotype is selected forSolemya parkinsonii. Live-collected specimens ofAcharax clarificatafrom methane seeps are described and illustrated. [ABSTRACT FROM PUBLISHER]

Hydrothermal vents in the deep sea have a global distribution on mid-ocean ridges and comprise at least six biogeographic provinces. A geographically isolated vent system was recently discovered on the Mid-Cayman Spreading Center (MCSC). Here, we describe the faunal assemblages associated with this system and their relationship to known biogeographic provinces. Taxa from MCSC vents were sorted based on morphology and barcoded using the cytochrome oxidase I (COI) and 16S ribosomal RNA (16S) genes for identification. Distinct faunal assemblages were recognized around vent chimneys at two hydrothermal vent fields (Von Damm and Beebe) separated by a distance of ~13 km and >2.5-km depth along the Mid-Cayman Spreading Center. These results suggest that depth and/or local conditions structure faunal assemblages in this region. COI and microsatellite markers were then used to explore the genetic structure of the shrimp Rimicaris hybisae , the only abundant species shared between the shallow Von Damm and the deep Beebe vent fields. R. hybisae was not genetically differentiated between the Von Damm Spire and Beebe chimneys, suggesting this species is better adapted for bathymetric dispersal and the differences in local conditions than other MCSC species. In addition, a third faunal assemblage dominated by two species of tubeworms was identified at Von Damm in association with weakly diffuse flow sites (including the site known as “Marker X18”). The Marker X18 assemblage shares species with seeps in the region. Fauna shared with both vents and seeps at the MCSC reinforces the need for a global biogeographic study of deep-sea chemosynthetic fauna that is not focused on specific habitats. [ABSTRACT FROM AUTHOR]

The Gulf of Mexico is one of the world's largest petroleum regions. Cantarell is an important oil field located in the Akal Pillar province. This region is characterized by several oil seeps. However, there is no consensus on the Cantarell oil seep subsurface provenance. Surface oil samples (seepage) and subsurface oil samples (reservoirs) from the Akal Pillar province were analyzed using gas chromatography with a flame ionization detector (GC-FID) and gas chromatography with a mass spectrometry detector (GC-MS). The data obtained were used to identify and characterize biomarker and diamondoid distributions. Multivariate statistical analyses of geochemical results were made to identify the Cantarell oil seep origin. Geochemical analysis showed small differences between the results which could help the correlation studies between the samples. Cluster analysis indicated a good correlation of the seepage samples with a unique subsurface oil sample, CAN8, from the reservoir in the Paleocene/Cretaceous breccia. [ABSTRACT FROM AUTHOR]