Streams in the mountains or the Arctic are especially harsh habitats. They are very cold, there are hardly any nutrients there, and they are frozen for half the year. And yet, there is a species of algae that not only survives in those streams but thrives there. Within a few days, Hydrurus foetidus covers almost every surface in those streams during its bloom season from late autumn to early spring. These blooms consist of thousands of filaments attached to the stones. Each of these filaments again houses thousands of individual Hydrurus foetidus organisms embedded in a shared structure. It is not understood at all how Hydrurus foetidus is able to thrive in this harsh environment and which strategies it uses to grow there.
In one part of this project, we investigate questions of nutrient utilisation and limitation in Hydrurus foetidus. Focusing on which nutrient sources are available to it and how it has optimised their use. For example, it has very high levels of enzymatic activity used to assimilate phosphorus from the surrounding waters. It also appears to be able to adapt its pigment content to light and nutrient availability. We are currently studying the exact mechanisms of these adaptations.
In the other part of this project, we study interactions between Hydrurus foetidus and bacteria as a potential adaptation. Across different streams, always the same microbes are found embedded in the Hydrurus foetidus filaments, suggesting they are selected by the algae to provide something. At the moment, we are identifying such potential interactions.
Both parts of this project include different levels of study and experimentations. We sample Hydrurus foetidus from many different streams across all of Valais, Switzerland, but we also closely monitor the growth in a single stream, the Borgne d’Arolla. In addition, we are maintaining an experiment with artificial flumes in Satarma, Evolène VS, to study the growth of Hydrurus foetidus in a more controlled setting. These experiments are supplemented by laboratory experiments studying the growth, nutrient content, and microbiome composition of the algae.
Project leaders: Stefan Eckensperger, PhD student and Aleksei Dukat, PhD student
Scientific and technical support: Matteo Tolosano, Nicola Deluigi, Florian Baier, Gregoire Michoud and Hannes Peter Markus
Principial Investigator: Prof Tom I. Battin
This project is funded by a SNSF grant
