Within the GeneStream project, we investigate the biodiversity of freshwater ecosystems on different levels. Combining traditional and novel methodological approaches we aim at 1) characterizing the gene flow and genetic diversity within species across habitats and anthropogenic barriers using population genomic approaches. 2) Using traditional taxonomic and DNA Barcoding approaches we will characterize the macrozoobenthic species diversity of the Breitenbach (Hesse, Germany) and other freshwater systems. 3) We will develop high-throughput sequencing protocols that build upon the Barcode databases with the aim to facilitate and improve freshwater ecosystem assessments using such metabarcoding approaches. 4) Using an innovative stream mesocosm system developed in recent years by our partners at the University of Otago (Dr. Jay Piggott and Dr. Christoph Matthaei*), we will investigate effects of single and multiple anthropogenic stressors on freshwater communities. This outdoor experimental setup is statistically powerful and tightly controlled, yet highly realistic (because it allows natural immigration and emigration of stream organisms). Pictures and videos of the setup at the central European low mountain stream “Breitenbach” can be viewed here.
Photo 1: With the ExStream System, developed by Jay Piggott, Christoph Matthaei and colleagues in New Zealand (University of Otago), we will study for responses of individual stream species, populations, and communities to singleand multiple stressor conditions. Water is directly taken from the stream and transferred into replicated mesocosms (circular stream channels; diameter 25 cm). In the first year, we will investigate for effects of climatic and agricultural stressors in a field experiment at the Breitenbach, one on the world’s best studied freshwater ecosystem.
*For more information on the experimental setup please have a look at the following publications of the Otago Stream Team:
- Liess A, Lange K, Piggott, JJ, Matthaei DC and Townsend RC (2009). Light, nutrients and grazing interact to determine diatom species richness via changes to productivity, nutrient state and grazer activity. Journal of Ecology, 97, 326-336. doi: 10.1111/j.1365-2745.2008.01463.x
- Lange K, Liess A, Piggott JJ, Townsend CR, and Matthaei CD (2011). Light, nutrients and grazing interact to determine stream diatom community composition and functional group structure. Freshwater Biology, 56(2), 264-278. doi: 10.1111/j.1365-2427.2010.02492.x
- Wagenhoff A, Townsend CR, and Matthaei CD (2012). Macroinvertebrate responses along broad stressor gradients of deposited fine sediment and dissolved nutrients: a stream mesocosm experiment. Journal of Applied Ecology, 49(4), 892-902. doi: 10.1111/j.1365-2664.2012.02162.x
More information in English to come in the next weeks.