Location
Univeresity of Nevada Las Vegas, Student Union Ball Room
Start Date
6-8-2009 9:30 AM
End Date
6-8-2009 12:00 PM
Description
15N-nitrate (NO3 -) pool dilution experiments show that ammonia (NH3) is oxidized to nitrate in geothermal springs up to at least 85C; however, nitrite (NO2 -)- oxidizing microorganisms are only known to grow up to 66°C. We hypothesize that thermophilic microorganisms oxidize nitrite to nitrate at high temperatures. Alternatively, it is possible that nitrite is oxidized abiotically. We propose to test these hypotheses by setting up microbial enrichments designed to grow thermophilic nitrite oxidizing bacteria by varying incubation temperature (50, 65, 80°C), oxygen concentration (20% and 5%), and cultivation media. A negative control consisting of filtered spring water (0.1 μm) will be used to determine whether nitrite is oxidized abiotically. Enrichments will be monitored for nitrite oxidation activity by using colorimetric assays for nitrite and nitrate. Enrichments showing activity will be used as a source to try to isolate and/or identify responsible microorganisms and to study the kinetics of nitrite oxidation at high temperature.
Keywords
Hot springs; Nitrate; Nitrite; Oxidation; Thermophiles; Extremophiles
Disciplines
Biogeochemistry | Fresh Water Studies | Geochemistry
Language
English
Researching nitrite oxidation at high temperatures
Univeresity of Nevada Las Vegas, Student Union Ball Room
15N-nitrate (NO3 -) pool dilution experiments show that ammonia (NH3) is oxidized to nitrate in geothermal springs up to at least 85C; however, nitrite (NO2 -)- oxidizing microorganisms are only known to grow up to 66°C. We hypothesize that thermophilic microorganisms oxidize nitrite to nitrate at high temperatures. Alternatively, it is possible that nitrite is oxidized abiotically. We propose to test these hypotheses by setting up microbial enrichments designed to grow thermophilic nitrite oxidizing bacteria by varying incubation temperature (50, 65, 80°C), oxygen concentration (20% and 5%), and cultivation media. A negative control consisting of filtered spring water (0.1 μm) will be used to determine whether nitrite is oxidized abiotically. Enrichments will be monitored for nitrite oxidation activity by using colorimetric assays for nitrite and nitrate. Enrichments showing activity will be used as a source to try to isolate and/or identify responsible microorganisms and to study the kinetics of nitrite oxidation at high temperature.
Comments
Abstract & poster