Cold-seep benthic communities in the Japan subduction zones: Geological control of community development

A large number of Calyptogena-dominated benthic communities, apparently chemosynthetically-based, were discovered at methane-rich pore-water seeps in the Japan subduction zones (3850–6000 m depth). Photographic and video surveys from four submersible dives were analyzed to study the influence of faulting, topography and substratum on exploitation of cold seeps by megafauna. Pore-water seepage occurred in a variety of geological settings, including subduction-erosion and accretionary prism formation, always in association with major faults which likely facilitated upward migration of fluids from a deep high-pressure zone. Sediment cover and manganese crusts on the seafloor appeared to block pore-water discharge, except where interrupted by erosion, slumping or outcropping. Sediment or mudstone substrata may increase lateral diffusion of rising fluids, permitting more extensive biological exploitation than where fluids discharge directly from exposed rock. Cold seeps are ephemeral. Large long-lived “fields” of cold seeps may be important in the maintenance of regional populations of seep organisms and the transfer of cold-seep productivity to the surrounding deep-sea ecosystem

Temporal and Vertical Oxygen Gradients Modulate Nitrous Oxide Production in a Seasonally Anoxic Fjord: Saanich Inlet, British Columbia

Nitrous oxide (N2O) is a strong greenhouse gas and an ozone depleting agent. In marine environments, N2O is produced biologically via ammonium oxidation, nitrite, and nitrate reduction. The relative importance of these principle production pathways is strongly influenced by oxygen availability. We conducted 15N tracer experiments of N2O production in parallel with measurements of N2O concentration and natural abundance isotopes/isotopomers in Saanich Inlet, a seasonally anoxic fjord, to investigate how temporal and vertical oxygen gradients regulate N2O production pathways and rates. In April, June, and August 2018, the depth of the oxic‐anoxic interface (dissolved oxygen = 2.5 μmol L−1 isoline) progressively deepened from 110 to 160 m. Within the oxygenated and suboxic water column, N2O supersaturation coincided with peak ammonium oxidation activity. Conditions in the anoxic deep water were potentially favorable to N2O production from nitrate and nitrite reduction, but N2O undersaturation was observed indicating that N2O consumption exceeded rates of production. In October, tidal mixing introduced oxygenated water from outside the inlet, displacing the suboxic and anoxic deep water. This oxygenation event stimulated N2O production from ammonium oxidation and increased water column N2O supersaturation while inhibiting nitrate and nitrite reduction to N2O. Results from 15N tracer incubation experiments and natural abundance isotopomer measurements both implicated ammonium oxidation as the dominant N2O production pathway in Saanich Inlet, fueled by high ammonium fluxes (0.6–3.5 nmol m−2 s−1) from the anoxic depths. Partial denitrification contributed little to water column N2O production because of low availability of nitrate and nitrite

Management and Conservation of Hydrothermal Vent Ecosystems Report from the InterRidge Workshop: Management and Conservation of Hydrothermal Vent Ecosystems

This report presents the first formal consideration by the international scientific community of the threat to the isolated hydrothermal vent "oasis" ecosystems from human activities. The aim of the report is to increase awareness among all potential users about the importance, fragility and potential value to society, through sustainable exploitation, of hydrothermal vent ecosystems. It is recognised that human impact on these ecosystems will only increase in the future and that gaining knowledge about them is crucial to sensible management or conservation policies. Because of the current poor understanding of these unique ecosystems, a conservative and precautionary approach is suggested to proposals for future use. The major findings of the report [with page numbers] are listed below. A section proposing measures for conservation and sustainable use begins near the end of the report on page 25

Temporal and spatial variation in temperature experienced by macrofauna at main endeavour Hydrothermal vent field

A significant focus of hydrothermal vent ecological studies has been to understand how species cope with various stressors through physiological tolerance and biochemical resistance. Yet, the environmental conditions experienced by vent species have not been well characterized. This objective requires continuous observations over time intervals that can capture environmental variability at scales that are relevant to animals. We used autonomous temperature logger arrays (four roughly parallel linear arrays of 12 loggers spaced every 10–12 cm) to study spatial and temporal variations in the thermal regime experienced by hydrothermal vent macrofauna at a diffuse flow vent. Hourly temperatures were recorded over eight months from 2010 to 2011 at Grotto vent in the Main Endeavour vent field on the Juan de Fuca Ridge, a focus area of the Ocean Networks Canada cabled observatory. The conspicuous animal assemblages in video footage contained Ridgeia piscesae tubeworms, gastropods (primarily Lepetodrilus fucensis), and polychaetes (polynoid scaleworms and the palm worm Paralvinella palmiformis). Two dimensional spatial gradients in temperature were generally stable over the deployment period. The average temperature recorded by all arrays, and in some individual loggers, revealed distinctive fluctuations in temperature that often corresponded with the tidal cycle. We postulate that this may be related to changes in bottom currents or fluctuations in vent discharge. A marked transient temperature increase lasting over a period of days was observed in April 2011. While the distributions and behavior of Juan de Fuca Ridge vent invertebrates may be partially constrained by environmental temperature and temperature tolerance, except for the one transient high-temperature event, observed fluid temperatures were generally similar to the thermal preferences for some species, and typically well below lethal temperatures for all species. Average temperatures of the four arrays ranged from 4.1 to 11.0 °C during the deployment, indicating that on an hourly timescale the temperature conditions in this tubeworm community were fairly moderate and stable. The generality of these findings and behavioural responses of vent organisms to predictable rhythmicity and non-periodic temperature shifts are areas for further investigation

Shining light on a deep-sea bacterial symbiont population structure with CRISPR

Many foundation species in chemosynthesis-based ecosystems rely on environmentally acquired symbiotic bacteria for their survival. Hence, understanding the biogeographic distributions of these symbionts at regional scales is key to understanding patterns of connectivity and predicting resilience of their host populations (and thus whole communities). However, such assessments are challenging because they necessitate measuring bacterial genetic diversity at fine resolutions. For this purpose, the recently discovered clustered regularly interspaced short palindromic repeats (CRISPR) constitutes a promising new genetic marker. These DNA sequences harboured by about half of bacteria hold their viral immune memory, and as such, might allow discrimination of different lineages or strains of otherwise indistinguishable bacteria. In this study, we assessed the potential of CRISPR as a hypervariable phylogenetic marker in the context of a population genetic study of an uncultured bacterial species. We used high-throughput CRISPR-based typing along with multi-locus sequence analysis (MLSA) to characterize the regional population structure of the obligate but environmentally acquired symbiont species Candidatus Endoriftia persephone on the Juan de Fuca Ridge. Mixed symbiont populations of Ca. Endoriftia persephone were sampled across individual Ridgeia piscesae hosts from contrasting habitats in order to determine if environmental conditions rather than barriers to connectivity are more important drivers of symbiont diversity. We showed that CRISPR revealed a much higher symbiont genetic diversity than the other housekeeping genes. Several lines of evidence imply this diversity is indicative of environmental strains. Finally, we found with both CRISPR and gene markers that local symbiont populations are strongly differentiated across sites known to be isolated by deep-sea circulation patterns. This research showed the high power of CRISPR to resolve the genetic structure of uncultured bacterial populations and represents a step towards making keystone microbial species an integral part of conservation policies for upcoming mining operations on the seafloor

Acupuncture for persistent allergic rhinitis: a multi-centre, randomised, controlled trial protocol

<p>Abstract</p> <p>Background</p> <p>Allergic rhinitis is one of the most common health complaints worldwide. Complementary and alternative medical approaches have been employed to relieve allergic rhinitis symptoms and to avoid the side effects of conventional medication. Acupuncture has been widely used to treat patients with allergic rhinitis, but the available evidence of its effectiveness is insufficient. Our objective is to evaluate the effectiveness of acupuncture in patients in Korea and China with persistent allergic rhinitis compared to sham acupuncture treatment or waitlist control.</p> <p>Methods</p> <p>This study consists of a multi-centre (two centres in Korea and two centres in China), randomised, controlled trial with three parallel arms (active acupuncture, sham acupuncture, and waitlist group). The active acupuncture and sham acupuncture groups will receive real or sham acupuncture treatment, respectively, three times per week for a total of 12 sessions over four weeks. Post-treatment follow-up will be performed a month later to complement these 12 acupuncture sessions. Participants in the waitlist group will not receive real or sham acupuncture treatments during this period but will only be required to keep recording their symptoms in a daily diary. After four weeks, the same treatment given to the active acupuncture group will be provided to the waitlist group.</p> <p>Discussion</p> <p>This trial will provide evidence for the effectiveness of acupuncture as a treatment for persistent allergic rhinitis. The primary outcome between groups is a change in the self-reported total nasal symptom score (i.e., nasal obstruction, rhinorrhea, sneezing, and itching) from baseline at the fourth week. Secondary outcome measures include the Rhinitis Quality of Life Questionnaire score and total non-nasal symptom score (i.e., headache, itching, pain, eye-dropping). The quantity of conventional relief medication used during the follow-up period is another secondary outcome measure.</p> <p>Trial registration</p> <p>Current Controlled Trials ISRCTN90807007</p

Automated Image Analysis for the Detection of Benthic Crustaceans and Bacterial Mat Coverage Using the VENUS Undersea Cabled Network

The development and deployment of sensors for undersea cabled observatories is presently biased toward the measurement of habitat variables, while sensor technologies for biological community characterization through species identification and individual counting are less common. The VENUS cabled multisensory network (Vancouver Island, Canada) deploys seafloor camera systems at several sites. Our objective in this study was to implement new automated image analysis protocols for the recognition and counting of benthic decapods (i.e., the galatheid squat lobster, Munida quadrispina), as well as for the evaluation of changes in bacterial mat coverage (i.e., Beggiatoa spp.), using a camera deployed in Saanich Inlet (103 m depth). For the counting of Munida we remotely acquired 100 digital photos at hourly intervals from 2 to 6 December 2009. In the case of bacterial mat coverage estimation, images were taken from 2 to 8 December 2009 at the same time frequency. The automated image analysis protocols for both study cases were created in MatLab 7.1. Automation for Munida counting incorporated the combination of both filtering and background correction (Median- and Top-Hat Filters) with Euclidean Distances (ED) on Red-Green-Blue (RGB) channels. The Scale-Invariant Feature Transform (SIFT) features and Fourier Descriptors (FD) of tracked objects were then extracted. Animal classifications were carried out with the tools of morphometric multivariate statistic (i.e., Partial Least Square Discriminant Analysis; PLSDA) on Mean RGB (RGBv) value for each object and Fourier Descriptors (RGBv+FD) matrices plus SIFT and ED. The SIFT approach returned the better results. Higher percentages of images were correctly classified and lower misclassification errors (an animal is present but not detected) occurred. In contrast, RGBv+FD and ED resulted in a high incidence of records being generated for non-present animals. Bacterial mat coverage was estimated in terms of Percent Coverage and Fractal Dimension. A constant Region of Interest (ROI) was defined and background extraction by a Gaussian Blurring Filter was performed. Image subtraction within ROI was followed by the sum of the RGB channels matrices. Percent Coverage was calculated on the resulting image. Fractal Dimension was estimated using the box-counting method. The images were then resized to a dimension in pixels equal to a power of 2, allowing subdivision into sub-multiple quadrants. In comparisons of manual and automated Percent Coverage and Fractal Dimension estimates, the former showed an overestimation tendency for both parameters. The primary limitations on the automatic analysis of benthic images were habitat variations in sediment texture and water column turbidity. The application of filters for background corrections is a required preliminary step for the efficient recognition of animals and bacterial mat patches

Perspectives on in situ Sensors for Ocean Acidification Research

As ocean acidification (OA) sensor technology develops and improves, in situ deployment of such sensors is becoming more widespread. However, the scientific value of these data depends on the development and application of best practices for calibration, validation, and quality assurance as well as on further development and optimization of the measurement technologies themselves. Here, we summarize the results of a 2-day workshop on OA sensor best practices held in February 2018, in Victoria, British Columbia, Canada, drawing on the collective experience and perspectives of the participants. The workshop on in situ Sensors for OA Research was organized around three basic questions: 1) What are the factors limiting the precision, accuracy and reliability of sensor data? 2) What can we do to facilitate the quality assurance/quality control (QA/QC) process and optimize the utility of these data? and 3) What sort of data or metadata are needed for these data to be most useful to future users? A synthesis of the discussion of these questions among workshop participants and conclusions drawn is presented in this paper