Microbubbles – hidden gateways for greenhouse gas emissions from inland waters?

Many inland waters emit the greenhouse gases carbon dioxide and methane at globally significant rates.

Recently, the surprising and impactful observation has been made in many lakes and rivers that methane is exchanged much faster than carbon dioxide. This effect could not be explained by established mechanisms and is currently unaccounted in global carbon models.

A recent hypothesis relates this effect to microscopically small bubbles (microbubbles) that may provide ‘hidden’ gateways for gas exchange.

This microbubble hypothesis has caused large controversies, but it remains unknown if microbubbles exist, how they are formed and how they affect gas exchange. Here, I aim to test the microbubble hypothesis for the first time.

Specifically, I will use lab and field experiments and mechanistic modelling to evaluate the existence and origin of microbubbles and their effect on the exchange of carbon dioxide and methane across various inland water types.

As microbubbles are invisible and therefore difficult to detect, I will apply novel acoustic techniques to sense microbubbles.

Biogeochemical effects of microbubbles is a rapidly expanding field of research and innovation in oceanography, engineering and medicine but has been largely neglected by inland water scientists.

This project will hence not only push the boundary in gas exchange research, but potentially also catalyze the micro-scale understanding of many other biogeochemical processes in inland waters.