Investigations on the fate, persistence and potential adverse effects resulting from the introduction of contaminants and microorganisms (genetically modified, biological pest control agents and pathogens) into the environment is a central research theme within our department.

Examples of our research are presented below.

We are developing and applying new partitioning based exposure methods to study the exposure and effects of chemical contaminants in various environmental media. Specifically, this involves methods for quantifying the availability of chemicals based on "equilibrium sampling devices (ESD)" that sense thermodynamic parameters, such as chemical activity. This approach is being used to for example determine the freely dissolved sediment pore water concentrations of contaminants in order to apply these in bioaccumulation models. For further information, please contact Philipp Mayer, phm@dmu.dk.

Passive dosing techniques are being developed and applied to provide well-defined and constant exposure of chemicals in a variety of toxicity tests. We also perform environmental risk analyses of chemical contaminants in the environment. Most notable in this regard are studies on the bioaccumulation of new contaminant classes in food chains. For example, we have studied the relationship between the concentration of brominated flame retardants (BFRs) and other persistent compounds in peregrine falcons and the thickness of their eggshells. This is one of the first studies to examine the potential risks of BFRs in birds of prey. Furthermore, we are working on the development of new methods within chemical fingerprinting, which uses patterns of persistent organic pollutants in fish to separate different populations on the basis of their feeding areas. For further information, please contact Philipp Mayer, phm@dmu.dk and Katrin Vorkamp, kvo@dmu.dk

Our approach for assessing the risk of introducing microorganisms into the environment is based on studies on the long-term persistence and the adverse effects on selected microbial processes and microbial community diversity, including studies on the exchange of genes. Studies on the fate, persistence and effects of microorganisms are performed using a variety of approaches, including specific tracking methodologies (e.g. genetic markers, physiological traits, fluorescence reporter strains), and measurements of densities over time in laboratory systems that model specific environmental compartments (e.g., the rhizosphere). Our studies deal with different scales of complexity, often starting with relatively simple experimental designs to answer specific questions, and then scaling up to more complex systems involving material sampled directly from the environment (soil, plant roots, etc.) and field scale studies. For further information, please contact  Niels Bohse Hendriksen, nbh@dmu.dk, Anne Winding, aw@dmu.dk or Niels Kroer, nk@dmu.dk.

By insertion of reporter genes, such as the green fluorescent protein gne, bacteria can be visualized under the microscope.

Studies of non-target effects of biological control agents (BCAs) on the diversity and function of indigenous communities of bacteria and protozoa are assessed using laboratory, mesocosm and greenhouse experiments. Through this research, techniques for detecting non-target effects are being developed, including PCR-based methods and time saving test systems. For further information, please contact Anne Winding, aw@dmu.dk

Organic grown tomatoes in green house. The growth medium has been treated with micobial pest control agents to inhibit plant pathogenic fungi.

The sustainability and fate of nanomaterials in the soil environment and any ecotoxicological effects of the nanomaterials on the soil microbiota are being assessed. Specific emphasis is given to the influence of naturally occurring degradation processes on the physical and chemical properties of nanomaterials, and the ecotoxicity of nanomaterials to bacteria, fungi and protozoa. For further information, please contact Anders Johansen, ajo@dmu.dk or Anne Winding, aw@dmu.dk.

The importance of horizontal gene transfer for the adaptation of bacteria to various stressors (e.g. antibiotics and metals) is well known. Often, phenotypes associated with pathogenicity, resistance to the immune system, and antibiotics treatments are associated with mobile genetic elements, such as plasmids. Conjugal transfer of plasmids is considered one of the most important mechanisms for the spreading of genetic material between bacteria. Research at the departments is aimed at identifying environmental ‘hot-spots’ for plamid transfer, and environmental factors that may influence the frequency of the transfer process. For further information, please contact Niels Kroer, nk@dmu.dk.

Transfer of a conjugal plasmid in a bacterial microcolony on the rhizoplane af barley. Green cells are donors carrying the plasmid, red cells (R) are potential recipients of the plasmid, while orange cells (T) are transconjugant cells having received the plasmid from the donor.

It is only very recently that clouds have attracted attention as a potential environment, where microbes can be concentrated or even proliferate. In addition, a completely new research discipline, bio-meteorology, has discovered the important role of bacteria in cloud formation, serving as ice nuclei. These new insights have led to the exciting scientific hypothesis that certain airborne bacteria may create their own environment by causing cloud formation, and that airborne bacteria may even undergo selection for their ability to participate in cloud formation. Using samples of cloud droplets, we are investigating the microbial diversity and functioning of microbes in the cloud environment. The sampled material is used for both direct cultivation of microbes and enumeration of living and dead cells. In addition, molecular techniques applied for analyzing the diversity of the microbial community and presence of ice-nucleation genes and virulence factors. For further information, please contact Ulrich B. Gosewinkel, uka@dmu.dk.

Air sampling device mounted on a Piper 28

Short abstracts of all ongoing projects can be seen here.