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Fish sampling at river Wigger (photo: EPFL)
October 27, 2017

In Switzerland – not to mention the rest of Europe and the United States – freshwater fish are falling victim to a deadly disease that is rampant in the summer and dormant in the winter. It is caused by a parasite that thrives in rivers and attacks salmonid fish in particular. Researchers from EPFL, Eawag and University of Bern have come up with a mathematical model for predicting outbreaks as part of a three-year joint research program. Read more

Pond snails are affected by temperature stress and exposure to micropollutants. (Photo: Marko Koenig, Imagebroker, Okapia)
October 16, 2017

In a laboratory experiment, Eawag ecologists studied how the pond snail Lymnaea stagnalis is affected by heatwaves, which are expected to become more frequent as a result of climate change. Snails exposed to temperature stress showed a greater investment in reproduction, egg production increasing by 60 per cent on average.  Read more

Collection of water samples from Lake Cadagno (canton of Ticino, 1920 m asl). (Photo: Eawag, Helmut Bürgmann)
October 5, 2017

Single-celled bacteria are capable of mixing water layers in lakes – not directly, by movement of their flagella, but by accumulating locally and thus increasing water density. The heavier water then sinks, creating circular currents. Researchers have now observed this process for the first time not just in the laboratory, but in a natural water body – Lake Cadagno (canton of Ticino). Read more

Fig.1: Scientists use electro-fishing to catch trout for their experiments. Photo: Petra Nobs, Eawag
October 3, 2017

Trout that live in stable ecosystems divide the prey spectrum among themselves and develop into specialists. In streams with instable food supply, however, the trout become generalists. Sticklebacks from different evolutionary lineages alter their environment by their feeding habits. This is deleterious to their descendants except they are hybrids. Understanding the interaction between species and environment is important for the effective protection of biodiversity.  Read more

Coenonympha hero, Vladimir Sazonov/Shutterstock.com
September 8, 2017

Imported plants, which proliferate widely along bodies of water, for example, are a threat to biodiversity. Based on data from biodiversity monitoring, the WSL, Eawag and the Helmholz Centre for Environmental Research in Halle investigated what influence 31 invasive neophytes have on butterflies in Switzerland.  Read more

The list of adverse effects caused by agriculture to waterbodies is a long one. Photo: Markus Zeh
September 5, 2017

Dried-up ponds, culverted streams, contamination with fertilisers and pesticides – the list of adverse effects caused by agriculture to water and waterbodies is a long one. Shortening this list is a major challenge, not only for agriculture but also for society as a whole. Supplying humanity with food is, after all, equally important. At the Eawag Info Day, experts demonstrated that the conflicts between use and protection can be addressed through objective dialogue, transparently stated goals and a broad raft of measures. Read more

July 19, 2017

Central Switzerland is shaped by Lake Lucerne, which offers not only rich landscape diversity but also habitats for numerous animal species. As part of the Swiss-wide “Projet Lac” study, the lake’s fish fauna was surveyed for the first time using standardized quantitative methods – producing some surprising findings. Read more

In the juvenile stage, the European eel (Anguilla anguilla) still has a transparent skin – hence the name “glass eel”. Photo: European Eel Foundation
June 21, 2017

European eels (Anguilla anguilla)  take three years to migrate from the spawning grounds in the Sargasso Sea (east of Florida) to the coasts of Europe, where they grow to maturity. En route, they are guided by subtle local differences in the Earth’s magnetic field. Read more

Rotsee, © Eawag
June 7, 2017

In freshwater lakes, large amounts of the greenhouse gas methane are oxidized by bacteria before it can be emitted into the atmosphere. A study in Lakes Rotsee and Zug has now shown that the bulk of this work is done, not by “classical” methane consumers, but by filamentous bacteria previously known only as contaminants of water supplies. Read more

Fieldwork on Lake Victoria
May 2, 2017

A conflict is developing in Africa’s Lake Victoria between fish farming in cages and the “normal” fishing industry. Added to that are other factors such as invasive species, wastewater pollution, pesticides and dam construction are putting the unique ecosystem under increasing pressure.  Read more

Fig. 1: Juvenile whitefish prior to their release from a hatchery into Lake Thun. (Photo: Emanuel Ammon, Ex-Press)
April 21, 2016

In the last century, the natural reproduction of whitefish and Arctic char in several Swiss lakes was adversely affected by high levels of nutrient inputs. So far, stocking measures have been implemented in efforts to support fish populations and maintain yields. The effectiveness of these measures varies according to the particular species and lake. Read more