The impact of abiotic factors on hybrid Daphnia populations across the Alps: are pollution effects irreversible?

The understanding of how chemical pollution affects ecosystems and their properties is still very limited. This poses severe constraints on our ability to define scientifically sound criteria for good ecological status with regard to the broad diversity of chemicals that may affect water bodies. Today, many freshwater bodies have recovered from antropogenically induced eutrophication 30 - 50 years ago. Nevertheless, toxic compounds are still present, together with climate change they are future threats that natural populations of planktonic organisms encounter. The group of Piet Spaak frequently observed interspecific hybridization of Daphnia (water flea) in a wide range of lakes North and South of the Alps. It is best explained by the eutrophication history of these. We want to study whether other influences than eutrophication like toxic compounds facilitated the dispersal of both species across their original borders, and how it affects the succession of taxa within a lake. We will analyse sediments for a broad range of contaminants from which some key components will be chosen for further studies on the bioaccumulation and effect in different mitochondrial haplotypes of Daphnia. Daphnia clones can be “resurrected” from sediment layers of up to 40 years old and we can study experimentally how they have adapted to changing pollutant concentrations in the lake.

Funding:

Swiss National Science Foundation

Publications:

Chiaia Hernandez, A., M. Krauss, J. Hollender. 2013. Screening of Lake Sediments for Emerging Contaminants by Liquid Chromatography Atmospheric Pressure Photoionization and Electrospray Ionization Coupled to High Resolution Mass Spectrometry. Environm. Sci. Technol. 47: 976-986.