If you are fascinated by the bubbling sound of streams, this thesis project (both Bachelor and Master) may be of interest for you:

Bubbles in streams function as gateways for gases such as carbon dioxide, methane or oxygen. Many streams emit carbon dioxide and methane to the atmosphere, which affects the global climate, and take up oxygen, which is crucially needed for any higher organism to breathe. Yet, how exactly these gases are exchanged remains unclear. Bubble size plays a critical role in how efficiently gases are exchanged between streams and the atmosphere, but to date, we are lacking data on bubble size distribution in streams (Fig. 1).

This thesis project seeks to scout for bubbles in streams, with particular focus on microscopically small and invisible bubbles (microbubbles) that could be particularly efficient gateways for gas exchange. The project will involve fieldwork in boreal and/or sub-arctic streams around Svartberget and/or Abisko, respectively. Fieldwork will take place during summer 2025 and is linked to an ongoing research project, hence we will be a team of at least three people in the field. You will use acoustic techniques to measure bubble concentrations and sizes in various types of streams. No prior knowledge on these techniques is needed, but a general interest and background knowledge in aquatic ecology, biogeochemistry, hydrology or hydrodynamics is required. The exact focus of the project is subject for discussion and depends on the student's interest, background and level (bachelor/master).

Don't hesitate to approach me to discuss opportunities! marcus.klaus@slu.se

The project will have fundamental implications for stream ecological and biogeochemical processes that involve gases.

Fig. 1. Waterfalls as primary sources of bubbles in streams.