Sophie Ruehr


Ecosystem reliance on groundwater

Groundwater is a critical freshwater resource for both people and ecosystems. Plants in arid and semi-arid systems often rely on groundwater throughout the year and during droughts. Access to water enables plants to continue fixing carbon from the atmosphere even under dry conditions. I use remote sensing and eddy covariance data to untangle the effects of groundwater depletion on ecosystems that are dependent on groundwater, with the goal of predicting carbon cycling and ecosystem function under future climate change.

A groundwater-dependent ecosystem in the Sierra Nevada

Solar-induced fluorescence

Solar-induced fluorescence (SIF) is a phenomenon of plants ‘glowing’ as they perform photosynthesis and capture carbon from the atmosphere. Rates of photosynthesis can change instantaneously depending on environmental conditions. Using SIF from satellite and ground-based sensors allows us to understand ecosystem responses to the environment and climate change over time and space.

SIF at a grassland in Point Reyes, CA

SIF at an experimental vineyard in Hopland, CA

Field work

Along with a team of other scientists and students, I am deploying a hyperpsectral imager at several sites in California. The imager takes ‘pictures’ of photosynthesis across a landscape, capturing differences in carbon fixation rates between individual plants and even leaves. We’re currently working with the imager to answer questions about drought, soil warming, and plant disease on carbon fixation rates. This work will help us understand terrestrial ecosystem functionality and predict carbon cycling under climate change.

The team at an AmeriFlux site deploying a hyperspectral imager