Das BayCEER-Kolloquium ist eine interdisziplinäre Plattform für Studierende, Wissenschaftler*innen und Interessierte: I.d.R. wöchentlich (in der Vorlesungszeit) werden Vorträge im Themenfeld Ökologie und Umweltwissenschaften gehalten, die anschließend im Plenum und in lockerer Atmosphäre während des Postkolloquiums diskutiert werden können. Gerne kann das Mittagessen mitgebracht werden (Brown Bag Lunch).

Programm Kolloquium Sommer 2024
(PDF) **** Kolloquiums-Newsletter für Interessierte **** Hinweise für Vortragende **** Hinweise für Einladende (PDF)

 

Terminplanung kommende Semester und Vortragsarchiv BayCEER Kolloquium

Vortragsreihe Ökologie und Umweltforschung WS 2010/11

Alle Termine
Dr. Jen-How Huang
Inst. f. Biogeochemie u. Schadstoffdynamik, ETH Zürich
Donnerstag, 18.11.2010 16:15-17:45 H6

Impact of microbial activity on arsenic reduction, mobilization and sequestration at the mineral-solution interface

eingeladen durch Prof Matzner.

The interaction of arsenic with mineral surfaces strongly influences its mobility in soil-water systems. Mircobial reduction of arsenate (As(V)) to arsenite (As(III)) may not only increase the mobility but also the toxicity of arsenic in the environment. While previous studies indicated that an uptake by mineral surfaces may slow down microbial As(V) reduction [2], detailed data on this effect is still lacking. Therefore, we investigated the influence of As(V) adsorption to ferrihydrite, goethite and boehmite on the kinetics of As(V) reduction by Shewanella putrefaciens CN-32 and Shewanella ANA-3 in incubation experiments. The As(V) adsorption was changed by varying concentrations of mineral suspension, adding competitive anions (phosphate, sulphate and exopolysaccahride) and the presence of microbial Fe reduction. The presence of minerals apparently decreased the microbial As(V) reduction kinetics. Increasing amounts of ferrihydrite, goethite or boehmite in suspension substantially decreased As(V) reduction rates. This effect increased from goethite to boehmite to ferrihydrite, in parallel with the specific surface area (600, 250, and 18 m2 g−1, respectively) and the As(V) adsorption affinity of the minerals. Both sorption competition with phosphate and bacterial exopolysaccharides isolated from S. putrefaciens enhanced As(V) reduction in the presence of mineral surfaces at low microbe-to-mineral ratios. Both Mössbauer and X-ray absroption spectroscopy indicated the formation of amorphous Fe (hydr)oxides, e.g. ferrihydrite and magnetite, during reductive dissolution of ferrihydrite, leading to sequestration of aqueous As species. In incubations with addition of electron shuttle compounds such as anthraquinone-2,6-disulfonate (AQDS), Fe(III) reduction may at the same time inhibit microbial As(V) reduction. The data presented highlighs the important role of microorganisms in the speciation and mobility of As at the mineral-soultion interface.



Weitere Informationen:Export as iCal: Export iCal
Aktuelle Termine



Antrittsvorlesung:
Mi. 22.05.2024 aktuell
Funktionelle Pilzökologie: Diversität und Prozesse auf unterschiedlichen Skalen
BayCEER-Kolloquium:
Do. 06.06.2024
Tracking plant diversity dynamics on islands over thousands of years
Mo. 10.06.2024
Arsenic biogeochemistry from paddy soil to rice grain
Dialog:
Do. 13.06.2024
ANL-Dialog Forschung & Praxis: Fließgewässerschutz im Klimawandel
Ökologisch-Botanischer Garten:
Mi. 29.05.2024
Führung | "Grüne Apotheke: Heilpflanzen"
Wetter Versuchsflächen
Luftdruck (356m): 967.4 hPa
Lufttemperatur: 15.2 °C
Niederschlag: 17.7 mm/24h
Sonnenschein: 1 h/d

...mehr
Diese Webseite verwendet Cookies. weitere Informationen