Picture: Jeremy Chane-tu

Picture: Noam Yaron Production x Nightcall Studio

Picture: Summit Foundation – Timothée Steiner

L’Odyssée des Lacs (ODL) is an eco-sports project led by Noam Yaron, a young Swiss, 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 by a combination of running, cycling and swimming, crossing 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 achievement. 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 to be 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 team has collected data on the biodiversity of the 10 lakes. To this end, Summit Foundation has collaborated with the ODL on an environmental DNA sequencing (eDNA) project, a biotechnology that makes it possible to identify species in an environment.

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 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 and 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 led to the conclusion that the quagga mussel has not yet colonised these 10 high-altitude lakes in Switzerland.


For more information, the full report on this scientific project is freely available at https://www.simplexdna.com/odyssee-des-lacs.

At the same time as the research project, the foundation has also compiled a description of the correct behaviour to adopt in the vicinity of high-altitude lakes. This list, which was designed 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. The aim is to limit contamination of the environment by invasive species, viruses or fungi, of which humans are major vectors of propagation. These organisms, which are barely visible to the naked eye, cling to equipment and take advantage of our movements between different water points 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. It is an invasive species that 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.

2) Don’t apply sunscreen before swimming

Although they are essential for preventing sunburn and skin damage, sun creams have a negative impact on the environment. These creams contain sunscreens or preservatives that act as endocrine disruptors, with potentially significant effects on aquatic species. There is therefore a link between UV filters and damage 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 water pocket. It is part of a much more complex ecosystem that includes vegetation, soil, 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, the best thing to do is to follow the guides to the lake, and only use the marked paths. The aim is to avoid creating new trampling zones, in order to protect soil dynamics and plant species, which are often fragile in Alpine environments. This rule is very important to observe, 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 damage them.

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

4) Small actions

In environments as fragile as mountain lakes, every little gesture is important in reducing our footprint. As these are sensitive environments, you don’t necessarily need a lot of disturbance to start changing the way they function. With this in mind, even the smallest gesture is important (see the Summit recommendations on the ODL website).

5) Social networks moderation

Social networks, even when used to raise environmental awareness, showcase places and make people want to go there. Paradoxically, this contributes indirectly to the degradation of an environment, because the more it is frequented, the greater the risk of irresponsible behaviour and the greater the degradation of the environment. The same applies to mountain lakes.

It is therefore important to share photos with moderation, as social networks are a powerful vector for the frequentation of the environment.. From this point of view, not indicating its location would prevent visitors from concentrating around the same lakes and would ensure a minimum of tranquillity for the environment.

Picture: Summit Foundation – Timothée Steiner