Aquatic Microbial Ecology

Micro but mighty!
Although microbes are only visible under a microscope, they are a key component in the uptake of organic carbon. Microbes either respire the organic carbon and produce carbon dioxide (CO2) or incorporate it into their biomass. Determining the mechanisms of carbon turnover by microbes is thus central for our understanding of the terrestrial carbon cycle and global climate change. The group Carbocrobe is working towards a better understanding of the function of the microbes and the metabolism of organic carbon in all types of inland waters.

Carbon Cycling from Source to Sea

Active or passive pipe?
Inland waters receive, process, emit, and store carbon in globally significant quantities. However, large hydrological events such as heavy rains introduce large amounts of organic carbon into inland waters. A large proportion of the pulsed organic carbon is shunted downstream turning streams into passive pipes. The timing and quantity of carbon processing and their mechanisms are not well understood. The  group Carbocrobe is working towards unraveling the mechanisms of carbon processing during transport from source to sea.

Environmental Change Research

Role of "Anthropocene"?
Humans are threatening inland waters by building dams and changing the water flow. We release polluted waters and use streams, rivers, and lakes for recreation. These anthropogenic stressors and their influence on the global carbon cycle are not yet well described. Climate change further impacts processes that occur during the transport of organic matter through our inland waters. The group Carbocrobe is working towards a better understanding of the impacts of anthropogenic and climate stressors on  carbon cycling in inland waters.

Outdoor flumes

• 6 x 40 m long
• flow and slope adjustable
• water from Oberer Seebach, an oligotrophic second order stream

Hyporheic flow-through microcosms

• 50 cm long, 4 cm diameter
• operated with a multi-channel pump
• can run as flow-through (continous) or closed loop (batch)

Monitoring

• S::can Spectrolyzer at inlet and outlet of Lake Lunz
• weekly analyses of dissolved organic carbon and absorbance/fluorescence
• ~since 2010

Lake monitoring

Measures profiles at the deepest point of the lake 3 times a day equipped with

1. Multiprobe HL7 (Ott Hydromet) with sensors for temperature, turbidity, oxygen, electrical conductivity, pH, and chlorophyll a
2. S:can Spectrolyzer for TOC, DOC, and NO3

Stream monitoring

Measures continously in Oberer Seebach at the inlet of the lake equipped with

1. Multiprobe EXO3s (ecoTech GmbH) with temperature, turbidity, oxygen, electrical conductivity, and pH
2. S:can Spectrolyzer for TOC, DOC, and NO3
3. Mini CO2 sensor (Pro-Oceanus)
4. Weather station with PAR, wind, and temperature sensor

Groundwater monitoring

Measures continously at two places in the catchment of Lake Lunz equipped with

1. Multiprobe EXO3s (ecoTech GmbH) with temperature, turbidity, oxygen, electrical conductivity, and pH
2. S:can Spectrolyzer for TOC, DOC, and NO3
3. Water level logger

The "WasserCluster" building on the western side of the lake. Three working groups, among them also Carbocrobe, are mostly working here.

The boat house or sea lab is located at the eastern side of the lake. At this place, one can either enjoy the silence or teach. The sea lab is used for courses given by teachers from WasserCluster , BOKU or the University of Vienna. The house is also the home of Elodea, one of two boats belonging to WasserCluster.

The  "Biological Station" on the eastern side of the lake and most often, even during winter, the sun is touching this building. Two working groups are mostly active here.