Photosynthesis and carbon fixation

Photosynthesis, the process by which energy from the sum is used to fix CO₂ into organic forms, is the main route through which carbon enters the biosphere, and thus has a major control over carbon dynamics. 

In our lab, we work on:

Measuring photosynthesis at the global scale

We leverage new observational tools that measure photosynthesis at the global scale. We rely on observations of Solar Induced Fluorescence (SIF), a phenomenon in which light absorbed by chlorophyll molecules is released as fluorescence. SIF is tightly linked to photosynthesis as it originates from the 

We develop new frameworks to connect local measurements of photosynthesis to global observations of SIF at the global scale through incorporation of explicit radiative transfer models at the leaf and canopy scale.

Understanding the limits of photosynthesis

We study the link between photosynthesis at the molecular scale and the global scale. Our past work has characterised the total abundance of the key enzyme responsible for photosynthetic carbon fixation - ribulose 2,5-bisphosphate oxygenase oxidase - rubisco (Bar-On & Milo, 2019). We found that whereas in the ocean rubisco is working close to its maximal capacity, on land rubisco is way less efficient - working at ≈1% capacity. Using a combination of field data, theory and modeling, we work to quantify the different factors limiting rubisco at the global scale, which will help to understand future dynamics of photosynthesis and their sensitivity to global change.

Estimating the sensitivity of photosynthesis to natural and human perturbation

We develop ways to robustly track long term changes in productivity at the global scale and at a high spatial resolution, which allows us to look at the response of photosynthesis and primary productivity to environmental and anthropogenic perturbations. Quantifying these responses can serve to parameterize existing and new components in terrestrial biosphere models, which are used to predict the future dynamics of the biosphere.