The wonders of Lake Cadagno tour the world in a TED-Ed video

• 15 May 2024
• 4 minutes

The unique features of the Piora Valley lake are told in just over five minutes through striking digitally animated illustrations. The collaboration with TED's initiative, aimed at young people and schools, is a first for a Ticino theme that becomes, thus, the protagonist of a TED video. The intention to make the video was born on the sidelines of the Agora project "Cadagno meromittico" by the Microbiology Institute and the Design Institute of SUPSI, in collaboration with the Alpine Biology Center Foundation in Piora, funded by the Swiss National Science Foundation (SNF).

Lake Cadagno and Val Piora are important scientific destinations because of their geological distinctiveness. For 40 years, in fact, the lake has become a unique model of study worldwide by combining an ecosystem of special scientific interest, the crenogenic meromixis, with the uniqueness of the presence of the scientific station managed by the Alpine Biology Center Foundation (CBA). The establishment of the laboratories and reception infrastructure at 2,000 m altitude managed by the CBA, founded in 1994 in collaboration with Canton Ticino (Department of Health and Social Affairs) and the universities of Geneva and Zurich, later joined by USI and SUPSI, was a key event in the enhancement of this alpine district, confirming its great scientific relevance.

While scientific research has advanced steadily, the sharing of this cultural richness has often remained confined almost exclusively to insiders. Thanks to the collaboration between the Microbiology Institute and the Design Institute of SUPSI (Department of Environment Construction and Design), the popularization gap is gradually being made up with a project supported by SNF Agora dedicated to disseminating the results of scientific research to the general public.

As part of the project, during a residential co-design workshop in Piora, scientists, science communicators, architects, designers and citizens were confronted with the idea of laying the groundwork for the creation of a dissemination exhibition in the CBA buildings. The workshop allowed them to get in touch with Bruno Giussani (journalist and European curator of TED conferences) and Daniele Zanzi (biologist and director of the autonomous body Faido Fit & Fun for the municipality of Faido), but also with the editors of TED-Ed, who were immediately enthusiastic about the idea of making the video on Lake Cadagno.

TED-Ed is the educational project of the nonprofit organization TED, known worldwide for its conferences dedicated to innovative ideas. Launched in 2012, TED-Ed targets young people and educational institutions and provides animated videos as tools to support teachers.

The video dedicated to Lake Cadagno was proposed by Daniele Zanzi and edited for the scientific part by Nicola Storelli, lecturer-researcher at the Microbiology Institute of SUPSI. It is the first content dedicated to Ticino to appear on the TED-Ed platform. In a little more than five minutes, the film made with digitally animated illustrations explains in terms suitable for everyone the scientific wonders of the meromictic lake of Cadagno and presents to a global audience the peculiarities of Val Piora.

A unique lake
Lake Cadagno is said to be meromictic, that is, permanently stratified with two layers of water overlapping each other, which never mix. The upper layer, called myxolimnion (from the surface to a depth of about 11 m), is similar to any other lake in the region, with oxygen-rich crystal-clear water that is conducive to the development of a good community of fish and other life typical of alpine lakes. The lower layer, called monimolimnion (13 m to sediment to about 21 m depth), is totally devoid of oxygen and rich in salts and other potentially toxic substances, such as hydrogen sulfide (H2S). The salts accumulate in the water flowing in the dolomite vein making it denser, flowing, then, to the bottom and entering the lake from sublacustrine springs.

Between the two permanently separated layers lies a small oxidoreductive transition zone (chemocline 11-13 meters deep) where oxygen disappears and a characteristic pink bacterial band develops, visible even to the naked eye, composed of special photosynthetic anaerobic bacteria (PSB: purple sulfur bacteria and GSB: green sulfur bacteria) that act as a "biological filter" using the toxic hydrogen sulfide and transforming it into sulfate (SO42-) in the process of anoxygenic photosynthesis. In this pink bacterial belt, a particular species of PSB called Chromatium okenii is able to mix considerable volumes of water due to its active flagellar motion, clustering in search of light in a narrow zone near the oxygen diffusion front. This accumulation of microorganisms increases the density of the water, which subsequently precipitates, dragging the Chromatium okenii along with it before swimming back to the light again, creating a bio-convention; a very rare phenomenon observed only sporadically in the oceans or in the laboratory. These microorganisms are believed to be likely similar to the earliest life forms present on Earth more than two billion years ago. The opportunity to study microorganisms that are almost completely extinct makes this lake a world-leading scientific resource.

The Agora project "Cadagno Meromittico"
The project "Cadagno Meromittico - A Journey into the History of Life through the Sublacustrine Ecosystem" aims to promote a scientific outreach campaign on the evolution of life through the strata of this peculiar lake basin, through a permanent exhibition in the CBA's buildings and a traveling preview of it that will stop in Ticino's middle and high schools.

Understanding the phenomenon of the stratification of the waters of Lake Cadagno and the peculiar characteristics of primitive microorganisms will provide the public with the elements to understand the starting point of the whole evolutionary process that led both to different evolutionary strategies and, at a later stage, to a massive biodiversity of life on our planet. At the same time, the "Cadagno Meromittico" project will accompany the public to discover a new perspective on one of the most beautiful alpine lakes in Canton Ticino and pay tribute to more than 100 years of scientific research in Val Piora, highlighting the most relevant studies and discoveries. The exhibition is scheduled to open in summer 2025.