The Odyssée des Lacs (ODL) is an eco-sports project led by Noam Yaron, a young Morgian, who has set himself the challenge of a triathlon across Switzerland in the summer of 2023. His ambition was to cross the country from east to west, combining running, cycling and swimming across 10 high-altitude lakes. Through the ODL, Noam has raised public awareness of water conservation and lake biodiversity by using the media impact of his feat. To support this initiative, Summit Foundation has joined forces as an environmental partner of the ODL, helping to set up a scientific and communication project around this challenge.

In Switzerland, the state of biodiversity is considered worrying, with half of the natural environments and a third of the species under threat. It is therefore vital to keep a close eye on the high-altitude lakes, which are fragile ecosystems, and this is why the ODL's scientific arm has been collecting data on the biodiversity of the 10 lakes. To do this, the Summit Foundation worked with the ODL on an environmental DNA sequencing (eDNA) project, a biotechnology that can identify species in an environment.

To this end, a member of the foundation accompanied Noam Yaron and his team throughout the challenge to carry out a sampling campaign. Depending on the size of the lakes, one or more water samples were collected from the surface and sent to a laboratory for eDNA sequencing. The results were then analysed and translated into understandable messages for the general public, but also made available to the communes and cantons to encourage them to carry out new inventories at a later date.

Summit Foundation has also used these eDNA analyses to assess the presence of the quagga mussel. (Dreissena bugensis)an invasive alien species originating from the Black Sea that is having a significant impact on aquatic ecosystems. In recent years, this mussel has proliferated in Swiss lakes, replacing local species and causing a significant loss of biodiversity. However, its presence in lakes at higher altitudes remains uncertain, and the ODL's scientific project has concluded that the quagga mussel has not yet colonised these 10 high-altitude lakes in Switzerland.

To find out more, the full report on this scientific project is available free of charge at this link : https://www.simplexdna.com/odyssee-des-lacs.

At the same time as the research project, the foundation also compiled a description of good behaviour to adopt in the vicinity of high-altitude lakes. This list, which was intended to raise public awareness and serve as a guide to reducing the impact of the ODL project on mountain lakes, is available below.

1) Cleaning of nautical equipment 

Before sailing or swimming in a mountain lake, it's important to thoroughly clean any equipment (boards, wetsuits) that has already been used on other bodies of water. This is to limit contamination of the environment by invasive species, viruses or fungi, which humans are major vectors for spreading. These organisms, which are barely visible to the naked eye, attach themselves to equipment and take advantage of our movements between different bodies of water to colonise new habitats. To stop them spreading, it is essential to clean, dry and inspect your equipment.

The best known example is the quagga mussel, which has colonised a large number of lakes in Switzerland, whereas just a few years ago it was completely absent from aquatic ecosystems. This invasive species reproduces everywhere, all year round, and has a colossal impact on the ecosystems in which it settles. By drawing heavily on resources (oxygen, nutrients), it endangers native flora and fauna and takes up all the space. It is therefore essential to avoid seeding it in mountain lakes, where its impact would be all the more devastating.

Although they are essential for preventing sunburn and skin damage, sunscreens have a harmful impact on the environment. These creams contain sunscreens or preservatives that act as endocrine disruptors, which can have significant effects on aquatic species. There is therefore a link between UV filters and the damage caused to flora and fauna, making aquatic areas and their biodiversity vulnerable. This is all the more true in mountain lakes, which are aquatic ecosystems that renew themselves slowly.

Controversial ingredients to avoid are :
- Benzophenone-3
- Octocrylene
- Homosalate
- Octinoxate

You should therefore opt for creams that do not contain these ingredients, and if necessary, buy products with recognised environmental labels that exclude UV filters:
- Ecolabel
- Ecocert
- Cosmos Organic

In all cases, it is important not to apply sun cream before swimming.

3) Use of trails

A mountain lake is unique and fragile, but it is more than just its visible pocket of water. It is part of a much more complex ecosystem that includes vegetation, soils, flora and fauna, where everything is interconnected and in constant interaction. In short, the good health of mountain lakes depends on the good health of the elements that surround them. It is important to be aware of this ecosystemic reality in order to put in place good usage practices. Protecting the entire ecosystem surrounding the lake means protecting the mountain lake.

With this in mind, a good practice to adopt is to respect the access guides to the lake, and to use only the signposted paths. The aim is to avoid creating new trampling zones, in order to protect the dynamics of the soil and plant species, which are often fragile in alpine environments. This rule is very important to respect, as the areas around mountain lakes also contain wetlands, which are often protected and provide refuge for species such as amphibians and dragonflies. The slightest trampling can harm them.

One way of respecting mountain lakes and the ecosystems on which they depend is to follow the path and avoid taking shortcuts.