Martin Ackermann, Professor für Molekulare Mikrobielle Ökologie an der ETH Zürich und Abteilungsleiter der Abteilung Umik an der Eawag, hat am ETH Tag 2015 die Goldene Eule des Verbandes der Studierenden der ETH (VSETH) entgegen nehmen dürfen. Weiterlesen
Hydrocarbon sources of cold seeps off the Vesterålen coast, northern Norway
We investigated active methane seeps in a water depth of 200 m in the Hola area off the coast of Vesterålen, northern Norway, to assess (1) hydrocarbon sources, (2) migration pathways and (3) the influence of hydrocarbon seepage on sediment pore water and water column chemistry. The seepage area is characterised by the presence of gas flares in the water column as revealed by hydro acoustic surveys and elevated methane concentrations of up to 42 nM ca. 5 m above the seafloor. Pore water analyses of three gravity cores from the seepage area show varying depths of the sulphate–methane-transition zone (SMTZ) between 80 cm and > 250 cm indicating spatially heterogeneous methane ascent. The isotopic composition of methane (δ13C from − 40‰ to − 63‰ and δ2H from − 191‰ to − 225‰) and δ13C depth profiles of methane and dissolved inorganic carbon show that the hydrocarbons are predominantly of thermogenic origin, consistent with δ13C values of C2 to C4 hydrocarbons. Isotope data also indicate considerable biodegradation of propane. Seismic profiles from the study area reveal major faults and steeply dipping unconformities between the basement and overlying Mesozoic sedimentary rocks. We propose that these act as migration pathways for the hydrocarbons from late Jurassic to early Cretaceous source rocks.
Hydrologic linkages drive spatial structuring of bacterial assemblages and functioning in alpine floodplains
Microbial community assembly and microbial functions are affected by a number of different but coupled drivers such as local habitat characteristics, dispersal rates, and species interactions. In groundwater systems, hydrological flow can introduce spatial structure and directional dependencies among these drivers. We examined the importance of hydrology in structuring bacterial communities and their function within two alpine floodplains during different hydrological states. Piezometers were installed in stream sediments and surrounding riparian zones to assess hydrological flows and also were used as incubation chambers to examine bacterial community structures and enzymatic functions along hydrological flow paths. Spatial eigenvector models in conjunction with models based on physico-chemical groundwater characteristics were used to evaluate the importance of hydrologically-driven processes influencing bacterial assemblages and their enzymatic activities. Our results suggest a strong influence (up to 40% explained variation) of hydrological connectivity on enzymatic activities. The effect of hydrology on bacterial community structure was considerably less strong, suggesting that assemblages demonstrate large functional plasticity/redundancy. Effect size varied between hydrological periods but flow-related mechanisms always had the most power in explaining both bacterial structure and functioning. Changes in hydrology should be considered in models predicting ecosystem functioning and integrated into ecosystem management strategies for floodplains.
Der faszinierende Kivusee und das gelöste Methan in seinem Tiefenwasser könnten eine ganze Forschungsanstalt auf Trab halten. Mit unseren Forschungsprojekten versuchen wir, Grundlagen für eine nachhaltige und sichere Nutzung des Methans zu schaffen.
Abwasser ist mit antibiotikaresistenten Bakterien belastet.
Wir untersuchen ihre Ausbreitung in die Umwelt und Gegenmassnahmen.
Anwendung eines feldtauglichen Kapillarelektrophorese-Geräts zur Analyse von Anionen und Kationen in kleinsten Probemengen