Dissolved methane pluming mapping using Membrane Inlet Mass-Spectrometry (MIMS) at a blowout site in the North Sea

A blow out site in the North Sea (well 22/4-b, UK EEZ) in a water depth of 83 m, served as a test area to demonstrate MIMS as a powerful tool for the continuous measurement of dissolved methane simultaneously to the partial pressure of carbon dioxide, nitrogen and oxygen as well as other gases. A pump-CTD arrangement was used to generate a continuous water stream through a 2.5 cm thick tube to the ship laboratory and was analyzed using a membrane inlet quadrupole mass spectrometer (GAM 200, InProcessInstruments). The pump-CTD was further equipped with calibrated HydroC CH4/CO2 sensors. The MIMS measurements were conducted under fully controlled temperature conditions and were calibrated for CH4, N2, O2, and pCO2. The pump-CTD arrangement was towed along transects across the blow out and dissolved gas concentrations as well as physical water column data were synchronized and geo-referenced. The transects were repeated in three different depth layers, including a bottom layer of � 2 m above the sea floor, 60 m above the sea floor just below the thermocline and a third plane in 10 m water depth. During the tows water samples were taken for later onboard methane analysis and cross-calibration with the MIMS and HydroC data. After data selection under consideration of the tidal regime lateral and vertical plume dimensions of dissolved methane were constructed. Dissolved methane concentrations ranged between background and up to about 18�M. Below the thermocline, which represents an effective barrier for the vertical distribution of dissolved methane, methane distinctively spreads laterally. Only at locations were the gas bubble stream and concurrently advected water from below the thermocline reaches the sea surface enhanced methane emission into the atmosphere took place

Erfassung gasförmiger Emissionen vom Auslauf eines Jungviehstalles mittels aktiver Probenahmehaube

Open stable systems with outdoor yards are used in organic cattle farming. Until now there are no emission factors in Germany for outdoor yards of dairy barns or of cattle barns generally. The measuring of the emission potential of gaseous substances (NH3, CO2, N2O and CH4) is difficult because of the size of the outdoor yards and the direct access by climate. One possibility to measure those emissions is the use of an active sampling hood. The sampling hood provides defined laminar exhaust airflow. The product of flow rate and concentration results in the emission mass flow. In a preliminary study six cattle in calf with a total of 7.19 GV had access to an outdoor yard. This was divided virtually in a 9 x 11 à 1 m² grid. To each m² a dirt level (clean, slightly, medium and heavily soiled) has been assigned. The grid area was sampled randomly. The influence of a scraper was investigated, too. The levels of dirtiness were allocated to the NH3 emission mass flows. Based on the rating the results of the random samples were transferred on the partial area of the entire outdoor yard. The outcome of this is an emission factor for NH3 of 3.02 kg/GV*a for the outdoor yard before the scraper was used and 2.79 kg/GV*a afterwards. The preliminary results show that measuring NH3 emissions by an active sampling hood is practicable for the use at outdoor yards of cattle barns

Untersuchungen zur erhöhten Toleranz von biofilmassoziierten Mikroorganismen und die Ausbildung von vbnc-Zuständen bei <em>Pseudomonas aeruginosa</em> gegenüber chlorabspaltenden Verbindungen

Im Mittelpunkt dieser Arbeit standen trinkwasserassoziierte Biofilme und der Einfluss den Desinfektionsmittel auf ihre bakteriellen Biofilmpopulationen haben können, wenn diese wiederholt oder dauerhaft in zu geringer Konzentration dosiert werden. Dazu wurde untersucht, wie sich Biofilme durch eine solche Behandlung entwickeln. Hierzu wurden die im Biofilm befindlichen Bakterien vor und nach der Behandlung charakterisiert. In weiterführenden Untersuchungen wurde die Reaktion von biofilmassoziiertem Pseudomonas aeruginosa auf die Behandlungen mit subletal dosierten Desinfektionsmitteln untersucht. In einem dritten Schritt sollte ermittelt werden, ob es möglich ist, P. aeruginosa durch Desinfektionsmittel in einen „viable but non-culturable“ Zustand (vbnc) zu überführen. Zu diesem Zweck wurde ein Verfahren etabliert, mit dem es möglich ist, Bakterienstämme auf ihre Suszeptibilität gegenüber Desinfektionsmitteln zu testen und gleichzeitig überprüft werden kann, ob Desinfektionsmittel in der Lage sind, den Zielorganismus in einen vbnc-Zustand zu überführen. Die Untersuchungen zum Einfluss von Desinfektionsmitteln auf die Biozönose der getesteten Biofilme zeigten auf der einen Seite die Wirksamkeit aller getesteten Desinfektionsmittel bzgl. der Reduktion von koloniebildenden Einheiten und in Bezug auf die Breite in der Diversität selbst. Auf der anderen Seite, zeigten die nach den Desinfektionen im Biofilm verbleibenden Spezies, unabhängig vom eingesetzten Desinfektionsmittel, hohe Übereinstimmung untereinander, so dass damit zu rechnen ist, dass diese persistierenden Stämme mitverantwortlich sind für die stete Neubesiedlung von Trinkwasserinstallationen. Die Versuche der mit Pseudomonas aeruginosa angeimpften Trinkwasserbiofilme zeigten, dass der Zielorganismus im Biofilm mittels quantitativer real-time PCR oder auch mittels PNA-FISH nachweisbar ist bzw. weiterhin Stoffwechselaktivität belegt werden kann und somit ein hygienisches Risiko darstellt. Mittels des eigens entwickelten Verfahrens, ist es zudem möglich geworden den Übergang von Mikroorganismen (hier: Pseudomonas aeruginosa) in den vbcn-Zustand gezielt herbeizuführen. Die in dieser Arbeit präsentierten Ergebnisse legen nahe, dass der falsche Einsatz von Desinfektionsmitteln widerstandfähige Biofilme heranzüchten kann. Sollte P. aeruginosa in der Lage sein bei nicht letaler Dosierung von Desinfektionsmitteln in einen lebensfähigen, aber nicht kultivierbaren Zustand überzugehen, könnten Desinfektionsmaßnahmen fälschlicherweise als erfolgreich gewertet werden, wenn Standardnachweise negativ bleiben

First-order reversal curve analysis of magnetoactive elastomers

The first magnetization loop and the first stress–strain cycle of magnetoactive elastomers (MAEs) in a magnetic field differ considerably from the following loops and cycles, possibly due to the internal restructuring of the magnetic filler particles and the matrix polymer chains. In the present study, the irreversible magnetization processes during the first magnetization of MAEs with different filler compositions and tensile moduli of the matrix are studied by first-order reversal curve (FORC) measurements. For MAEs with mixed magnetic NdFeB/Fe fillers the FORC distributions and magnetization distributions of the first major loop reveal a complex irreversible magnetization behavior at interaction fields Hu 600 kA m−1

Thermocline mixing and vertical oxygen fluxes in the stratified central North Sea

In recent decades, the central North Sea has been experiencing a general trend of decreasing dissolved oxygen (O2) levels during summer. To understand potential causes driving lower O2, we investigated a 3-day period of summertime turbulence and O2 dynamics in the thermocline and bottom boundary layer (BBL). The study focuses on coupling biogeochemical with physical transport processes to identify key drivers of the O2 and organic carbon turnover within the BBL. Combining our flux observations with an analytical process-oriented approach, we resolve drivers that ultimately contribute to determining the BBL O2 levels. We report substantial turbulent O2 fluxes from the thermocline into the otherwise isolated bottom water attributed to the presence of a baroclinic near-inertial wave. This contribution to the local bottom water O2 and carbon budgets has been largely overlooked and is shown to play a role in promoting high carbon turnover in the bottom water while simultaneously maintaining high O2 concentrations. This process may become suppressed with warming climate and stronger stratification, conditions which could promote migrating algal species that potentially shift the O2 production zone higher up within the thermocline

Der Auslauf in der ökologischen Schweinemast: Verschmutzungsverteilung und Ammoniakemissionen

Ammonia emissions are an important problem in agricultural systems. Organic pig production raises a claim to offer high animal welfare. However, gaseous emissions can exhaust out of outdoor runs. Many measurement technics to determine the ammonia volatilization in animal facilities exist. In outdoor runs it is necessary to define the air volume flow. In addition, the contaminated surface of the pig-yard is heterogeneous. Therefore, it is interesting if the ammonia concentration correlate with the amount of manure. The outdoor run has been divided in a matrix. The ammonia concentrations are determined with a multi-gas monitor (INNOVA 1312) in combination with a dynamic chamber. The study showed a difference in ammonia volatilization between roofed and unroofed outdoor runs. Furthermore there is a high variability of the Ammonia concentrations in the different patches of the matrix

Efficiency and adaptability of the benthic methane filter at Quepos Slide cold seeps, offshore Costa Rica

Large amounts of methane are delivered by fluids through the erosive forearc of the convergent margin offshore Costa Rica and lead to the formation of cold seeps at the sediment surface. Besides mud extrusion, numerous cold seeps are created by landslides induced by seamount subduction or fluid migration along major faults. Most of the dissolved methane reaching the seafloor at cold seeps is oxidized within the benthic microbial methane filter by anaerobic oxidation of methane (AOM). Measurements of AOM and sulfate reduction as well as numerical modeling of porewater profiles revealed a highly active and efficient benthic methane filter at Quepos Slide site; a landslide on the continental slope between the Nicoya and Osa Peninsula. Integrated areal rates of AOM ranged from 12.9 ± 6.0 to 45.2 ± 11.5 mmol m-2 d-1, with only 1 to 2.5% of the upward methane flux being released into the water column. Additionally, two parallel sediment cores from Quepos Slide were used for in vitro experiments in a recently developed Sediment-F low-Through (SLOT) system to simulate an increased fluid and methane flux from the bottom of the sediment core. The benthic methane filter revealed a high adaptability whereby the methane oxidation efficiency responded to the increased fluid flow within 150–170 days. To our knowledge, this study provides the first estimation of the natural biogeochemical response of seep sediments to changes in fluid flow

Differenzierte Bioaerosolmessungen: Größenfraktionierte und kontinuierliche Messung von Bioaerosolen in der Emission von Geflügelhaltungen

Es wurden erstmals die Größenverteilungen von Bioaerosolen, sowie deren tageszeitlicher Konzentrationsverlauf in der Emission von Anlagen zur Geflügelhaltung mittels standardisierter Verfahren bestimmt. Die Ergebnisse richten sich im Rahmen von Genehmigungsverfahren an Anlagenbetreiber, Gutachter und Behörden. Sie legen nahe, dass zukünftig sowohl die Partikelgrößenverteilung, als auch die tageszeitlichen Emissionsschwankungen bei der Ausbreitungsrechnung von Bioaerosolen berücksichtigt werden sollten. Bezüglich der verwendeten Emissionsfaktoren wird eine Halbierung des Konventionswertes für Legehennen und Putenmast aufgezeigt, bezüglich des Größenklassenspektrums für Anlagen der Geflügelhaltung eine Aufteilung von 15 % PM 2,5; 25 % PM 10; und 60 % TSP. Redaktionsschluss: 31.01.201

Ammonia emissions from livestock: range and mitigation options

Die Tierhaltung in Deutschland muss angesichts der erheblichen Überschreitung der nationalen Emissionsobergrenze für Ammoniak und als deren Hauptverursacher weitreichende Maßnahmen zur Emissionsminderung ergreifen und prüfbar umsetzen. Hierfür steht eine Fülle von Optionen in der gesamten Verfahrenskette, angefangen von der Fütterung bis hin zur Ausbringung von Wirtschaftsdüngern, zur Verfügung. Die Abluftreinigung ist eine wirksame und prüfbare Maßnahme zur Minderung von Emissionen aus zwangsbelüfteten Tierhaltungsanlagen. Zur Reduzierung der Kosten für die Abluftreinigung und zur Verbesserung des Tierwohls könnte auch eine innovative Stallluftführung beitragen, bei der nur hochbelastete Teilströme unterflur abgesaugt und gereinigt werden.In view of considerable exceeding the national emission limit for ammonia the livestock in Germany as its major source has to take extensive action for reduction and testable implementation. A package of measures is available for the whole production process, beginning with feeding up to application of manure. Exhaust air treatment is one effective and testable option for emission reduction from forced ventilated livestock housings. Innovative and intelligent stable air guidance with treatment of highly loaded, underfloor sucked branch current may contribute to both, a reduction of exhaust air treatment costs and for improving animal welfare

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