In situ benthic fluxes from an intermittently active mud volcano at the Costa Rica convergent margin

Along the erosive convergent margin off Costa Rica a large number of mound-shaped structures exist built by mud diapirism or mud volcanism. One of these, Mound 12, an intermittently active mud volcano, currently emits large amounts of aqueous dissolved species and water. Chemosynthetic vent communities, authigenic carbonates, and methane plumes in the water column are manifestations of that activity. Benthic flux measurements were obtained by a video-guided Benthic Chamber Lander (BCL) deployed at a vent site located in the most active part of Mound 12. The lander was equipped with 4 independent chambers covering adjacent areas of the seafloor. Benthic fluxes were recorded by repeated sampling of the enclosed bottom waters while the underlying surface sediments were recovered with the lander after a deployment time of one day. One of the chambers was placed directly in the centre of an active vent marked by the occurrence of a bacterial mat while the other chambers were located at the fringe of the same vent system at a lateral distance of only 40 cm. A transport-reaction model was developed and applied to describe the concentration profiles in the pore water of the recovered surface sediments and the temporal evolution of the enclosed bottom water. Repeated model runs revealed that the best fit to the pore water and benthic chamber data is obtained with a flow velocity of 10 cm yr− 1 at the centre of the vent. The flux rates to the bottom water are strongly modified by the benthic turnover (benthic filter). The methane flux from below at the bacterial mat site is as high as 1032 μmol cm− 2 yr− 1, out of which 588 μmol cm− 2 yr− 1 is oxidised in the surface sediments by microbial consortia using sulphate as terminal electron acceptor and 440 μmol cm− 2 yr− 1 are seeping into the overlaying bottom water. Sulphide is transported to the surface by ascending fluids (238 μmol cm− 2 yr− 1) and is formed within the surface sediment by the anaerobic oxidation of methane (AOM, 588 μmol cm− 2 yr− 1). However, sulphide is not released into the bottom water but completely oxidized by oxygen and nitrate at the sediment/water interface. The oxygen and nitrate fluxes into the sediment are high (781 and 700 μmol cm− 2 yr− 1, respectively) and are mainly driven by the microbial oxidation of sulphide. Benthic fluxes were much lower in the other chambers placed in the fringe of the vent system. Thus, methane and oxygen fluxes of only 28 and 89 μmol cm− 2 yr− 1, respectively were recorded in one of these chambers. Our study shows that the aerobic oxidation of methane is much less efficient than the anaerobic oxidation of methane so that methane which is not oxidized within the sediment by AOM is almost completely released into the bottom water. Hence, anaerobic rather than aerobic methane oxidation plays the major role in the regulation of benthic methane fluxes. Moreover, we demonstrate that methane and oxygen fluxes at cold vent sites may vary up to 3 orders of magnitude over a lateral distance of only 40 cm indicating an extreme focussing of fluid flow and methane release at the seafloor

Enhanced lifetime of methane bubble streams within the deep ocean

We have made direct comparisons of the dissolution and rise rates of methane and argon bubbles experimentally released in the ocean at depths from 440 to 830 m. The bubbles were injected from the ROV Ventana into a box open at the top and the bottom, and imaged by HDTV while in free motion. The vehicle was piloted upwards at the rise rate of the bubbles. Methane and argon show closely similar behavior at depths above the methane hydrate stability field. Below that boundary (∼520 m) markedly enhanced methane bubble lifetimes are observed, and are attributed to the formation of a hydrate skin. This effect greatly increases the ease with which methane gas released at depth, either by natural or industrial events, can penetrate the shallow ocean layers

The Baltic Sea Tracer Release Experiment. Part I: Mixing rates

In this study, results from the Baltic Sea Tracer Release Experiment (BATRE) are described, in which deep water mixing rates and mixing processes in the central Baltic Sea were investigated. In September 2007, an inert tracer gas (CF3SF5) was injected at approximately 200 m depth in the Gotland Basin, and the subsequent spreading of the tracer was observed during six surveys until February 2009. These data describe the diapycnal and lateral mixing during a stagnation period without any significant deep water renewal due to inflow events. As one of the main results, vertical mixing rates were found to dramatically increase after the tracer had reached the lateral boundaries of the basin, suggesting boundary mixing as the key process for basin-scale vertical mixing. Basin-scale vertical diffusivities were of the order of 10−5 m2 s−1 (about 1 order of magnitude larger than interior diffusivities) with evidence for a seasonal and vertical variability. In contrast to tracer experiments in the open ocean, the basin geometry (hypsography) was found to have a crucial impact on the vertical tracer spreading. The e-folding time scale for deep water renewal due to mixing was slightly less than 2 years, the time scale for the lateral homogenization of the tracer patch was of the order of a few months. Key Points: Mixing rates in the Gotland Basin are dominated by boundary mixing processes; The time scale for Gotland Basin deep water renewal is approximately 2 years; Mixing rates determined from the tracer CF3SF

Continuous inline mapping of a dissolved methane plume at a blowout site in the Central North Sea UK using a membrane inlet mass spectrometer – water column stratification impedes immediate methane release into the atmosphere

Highlights: • MIMS used to quantify the dissolved CH4 inventory around a bubble emission site. • Conservative estimate of well 22/4b seabed CH4 emission was 1.8 ktons yr−1. • Stratification impedes immediate CH4 release into the atmosphere. The dissolved methane (CH4) plume rising from the crater of the blowout well 22/4b in the Central North Sea was mapped during stratified water column conditions. Geochemical surveys were conducted close to the seafloor at 80.3 m water depth, below the thermocline (61.1 m), and in the mixed surface layer (13.2 m) using membrane inlet mass spectrometry (MIMS) in combination with a towed CTD. Seawater was continuously transferred from the respective depth levels of the CTD to the MIMS by using an inline submersible pump. Close to the seafloor a well-defined CH4 plume extended from the bubble release site ∼460 m towards the southwest. Along this distance CH4 concentrations decreased from a maximum of 7872 nmol l−1 to less than 250 nmol l−1. Below the thermocline the well-defined CH4 plume shape encountered at the seafloor was distorted and filaments were observed that extended towards the west and southwest in relation to current direction. Where the core of the bubble plume intersected this depth layer, footprints of high CH4 concentrations of up to 17,900 nmol l−1 were observed. In the mixed surface layer the CH4 distribution with a maximum of up to 3654 nmol l−1 was confined to a small patch of ∼60 m in diameter. The determination of the water column CH4 inventories revealed that CH4 transfer across the thermocline was strongly impeded as only ∼3% of the total water column inventory was located in the mixed surface layer. Best estimate of the CH4 seabed release from the blowout was 1751 tons yr−1. The fate of the trapped CH4 (∼97%) that does not immediately reach the atmosphere remains speculative. In wintertime, when the water column becomes well mixed as well as during storm events newly released CH4 and the trapped CH4 pool can be transported rapidly to the sea surface and emitted into the atmosphere

Superoxide release and cellular gluthatione peroxidase activity in leukocytes from children with persistent asthma

Asthma is an inflammatory condition characterized by the involvement of several mediators, including reactive oxygen species. The aim of the present study was to investigate the superoxide release and cellular glutathione peroxidase (cGPx) activity in peripheral blood granulocytes and monocytes from children and adolescents with atopic asthma. Forty-four patients were selected and classified as having intermittent or persistent asthma (mild, moderate or severe). The spontaneous or phorbol myristate acetate (PMA, 30 nM)-induced superoxide release by granulocytes and monocytes was determined at 0, 5, 15, and 25 min. cGPx activity was assayed spectrophotometrically. The spontaneous superoxide release by granulocytes from patients with mild (N = 15), moderate (N = 12) or severe (N = 6) asthma was higher at 25 min compared to healthy individuals (N = 28, P andlt; 0.05, Duncan test). The PMA-induced superoxide release by granulocytes from patients with moderate (N = 12) or severe (N = 6) asthma was higher at 15 and 25 min compared to healthy individuals (N = 28, P andlt; 0.05 in both times of incubation, Duncan test). The spontaneous or PMA-induced superoxide release by monocytes from asthmatic patients was similar to healthy individuals (P \u3e 0.05 in all times of incubation, Duncan test). cGPx activity of granulocytes and monocytes from patients with persistent asthma (N = 20) was also similar to healthy individuals (N = 10, P \u3e 0.05, Kruskal-Wallis test). We conclude that, under specific circumstances, granulocytes from children with persistent asthma present a higher respiratory burst activity compared to healthy individuals. These findings indicate a risk of oxidative stress, phagocyte auto-oxidation, and the subsequent release of intracellular toxic oxidants and enzymes, leading to additional inflammation and lung damage in asthmatic children

Person-centered approaches to examining links between self-regulation and conduct problems, attention-deficit/hyperactivity disorder, and callous-unemotional behaviors in childhood

Over the past two decades, the study of self-regulation and its associations with emerging psychopathology has become a major pursuit in developmental science. Early-childhood emotion regulation (ER) and executive function (EF), in particular, are interrelated aspects of self-regulation that have garnered extensive research and are theorized to promote social competence school readiness and achievement, and adjustment. However, the development of self-regulation is a complex process that occurs through coaction at multiple levels of analysis. Three studies were conducted to examine biobehavioral emotion responding in infancy, early childhood EF, and their prospective influences on trajectories of conduct problems (CPs), attention-deficit/hyperactivity disorder (ADHD), and callous-unemotional (CU) behaviors using multiple person-centered approaches. Study 1 used latent profile analysis (LPA) to prospectively examine the synchrony and asynchrony of infant behavioral reactivity, cortisol reactivity, and ER behaviors at 6, 15, and 24 months of age to determine whether groups of infants evidenced different patterns of arousal and regulation; and whether such patterns were bidirectionally related to parenting behavior over the same span of time. Study 2 used longitudinal latent class analysis (LLCA) to examine joint trajectories of CPs, ADHD symptoms, and CU behaviors from 3 years old to 5th grade in order to assess examine heterogeneity in CPs based on the presence of ADHD and CU behaviors. Study 3 built upon the prior two studies by in by investigating associations of infants’ emotional arousal and regulation with their later CP/ADUD/CU trajectories, as well as the role of early childhood EF in mediating these prospective associations. Results from Study 1 indicated that there is observable variation in infants’ patterns of behavioral reactivity, cortisol reactivity, and ER behaviors across infancy, and that infant emotion responding and parent sensitivity and harsh-intrusion were bidirectionally predictive of one another. Results from Study 2 showed that children did follow differing trajectories of CPs, but that these varied based on who reported their behavior (parents, teachers, or both), rather than on trajectories of ADHD symptoms and CU behaviors. In addition, these joint trajectories differentiated children’s likelihood of meeting diagnostic criteria for oppositional defiant disorder, conduct disorder, and ADHD, as well as clinically significant levels of CU behaviors, during preadolescence. Finally, results from Study 3 indicated that infants’ patterns of emotion responding were not prospectively related to their CP/ADHD/CU trajectories or their early childhood EF. However, better EF did significantly predict a decreased likelihood of following trajectories characterized by high problem behavior as rated by both parents and teachers, parents only, and teachers only. The implications for understanding the early development of self-regulation, CPs, ADHD, and CU behaviors are discussed, as is the utility of innovative person-centered approaches for understanding these phenomena

Surgical Reconstruction of the Urinary Sphincter after Traumatic Longitudinal Disruption

The question is whether the urethral sphincter may be reconstructed after longitudinal injury similar to anal sphincter injuries. Analogue to obstetric, anal sphincter repair, an approximation repair of the sphincter may be feasible. An overlap repair is possible in anal sphincter repair, but because of the little tissue available in the urethral sphincter this is not an option. We describe three cases of urethral sphincter injury of different aetiologies. All resulted in a total longitudinal disruption of the muscular components of the urethral sphincter complex. After making the diagnosis of urethral sphincter injury, a primary approximation repair was done. Follow-up of at least two and up to three years is promising with one male patient being completely continent and the two female patients needing one safety pad per day. Longitudinal disruption of the muscular elements of the sphincteric urethra may be primarily reconstructed with good success using an approximation technique with simple interrupted sutures

Emotion recognition deficits among children with conduct problems and callous-unemotional behaviors: differences by child race

Deficits in emotion recognition have been associated with psychopathic and callous-unemotional (CU) behaviors among adults, adolescents, and children. However, few previous studies have examined such associations exclusively during early and middle childhood. The current study used a large, population-stratified, randomly-selected sample of 2nd grade children living in areas of high rural poverty to examine group differences in emotion recognition among children showing no conduct problems or CU behaviors (typical), conduct problems without CU behaviors (CP-only), and both CP and CU behaviors (CP+CU). Primary caregivers reported on children’s conduct problems and callous-unemotional behaviors at 1st grade and children completed a computerized facial emotion recognition task at 2nd grade. Results indicated that group differences in emotion recognition accuracy were moderated by child race, with children in the typical group showing better overall accuracy and better recognition of fearful and happy faces among European American children, whereas no group differences were found among African American children. Implications for emotion socialization, etiology of CP and CU behaviors, and future directions for research and treatment are discussed