Environmental DNA analysis makes it possible to detect water organisms without having to capture them first. For the first time, a team at the Technical University of Munich (TUM) systematically investigated the effect of various environmental factors on environmental DNA analyses. By doing so, the researchers have made an important step towards the standardized application of this method for the monitoring of water bodies.
DNA that animals release into aquatic environment can be detected using molecular analysis. This detection method is called environmental DNA (eDNA) A simple water sample is sufficient for this technique.
However, this method does not work equally well in all water bodies and is therefore very likely to be influenced by the respective conditions in each body of water. This may include organic and inorganic components in the water or the flow conditions. So far, there is almost no research on how strongly the individual factors affect the analysis procedure.
Dr. Bernhard Stoeckle and Dr. Sebastian Beggel, researchers at the Chair of Aquatic Systems Biology and the Unit of Molecular Zoology (Chair of Zoology) at TUM investigated the influence of a wide range of environmental factors on eDNA analysis in an experiment. The idea for the experiment was based on a previous eDNA study on a native mussel species.
Systematic experimental structure
In a systematic laboratory setup, fish belonging to an invasive species — the round goby (Neogobius melanostomus) — were kept in aquaria in varying densities, under various flow conditions, with and without sediment, and were removed from the water after a defined period of time.
Subsequently, the researchers took water samples at regular intervals over a period of six days in order to be able to evaluate the efficiency of the eDNA analysis over time as well. In addition, the researchers added several substances, which could potentially hinder molecular analysis such as algae, humic substances, and inorganic suspended particles to the water, which are also found in natural ecosystems.
“That’s particularly important, otherwise we wouldn’t be able to apply the findings to eDNA studies in the field,” Bernhard Stoeckle explained. In order to find out which factors have the greatest influence, the researchers then compared the eDNA results of all water samples with each other.
Extent of influence of factors changes over time
On the one hand, the evaluation of the experiment showed that, over its entire duration, the flow conditions, the existence or absence of sediment, and the fish density only had an effect on the analyses in combination with each other. On the other hand, it turned out that the extent of the influence of the factors changed greatly over time.
Of the inhibitors added, organic substances (humic substances) interfered with the analyses the most. They often entirely precluded the successful application of the method. DNA could only be detected in 41 percent of the samples examined. Algae also had a comparable effect, albeit less pronounced. “Our findings clearly demonstrate how important it is that environmental conditions are also taken into account when performing eDNA analyses in order to be able to correctly interpret the findings,” said Bernhard Stoeckle.
Based on the results of the experiment, it can be concluded that specific environmental conditions interfere greatly with environmental DNA experiments, in some cases making it difficult or even impossible to detect species.
Pictures for editorial coverage
Stoeckle, BC., Beggel, S., Cerwenka, AF., Motivans, E., Kuehn, R., Geist, J.: A systematic approach to evaluate the influence of environmental conditions on eDNA detection success in aquatic ecosystems, PLoS One 12/2017.
Prof. Dr. Jürgen Geist
Technical University of Munich
Chair of Aquatic Systems Biology
Dr. Ulrich Marsch | Technische Universität München
Colorectal cancer risk factors decrypted
13.07.2018 | Max-Planck-Institut für Stoffwechselforschung
Algae Have Land Genes
13.07.2018 | Julius-Maximilians-Universität Würzburg
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
13.07.2018 | Event News
13.07.2018 | Materials Sciences
13.07.2018 | Life Sciences