The Max Planck Institute for Biogeochemistry (MPI-BGC) in Jena is dedicated to interdisciplinary fundamental research in the field of Earth system sciences with a focus on climate and ecosystems. The internationally renowned institute, which currently employs around 250 people, celebrated its 25th anniversary in 2022. Jena is known for high-tech industry, internationally renowned research institutions and a modern university, but it also has a beautiful natural setting in the green Saale valley with steep limestone slopes. The city of Jena has an active student scene and a diverse cultural life. We are looking to fill a PhD position (m/f/d) - has the Amazon’s southeastern vegetation lost its carbon uptake capacity? for 3 years, starting in September 2025 at the earliest.

Background and position description

The Amazon Tall Tower Observatory (ATTO) project is a German-Brazilian research collaboration dedicated to improving our understanding of processes in intact Amazonian forests and their interactions with the atmosphere in the changing Earth system. Recent research has suggested that the vegetation of southeastern Amazonia has lost its carbon uptake capacity, raising concern over the potential for climate change and increasing disturbance to amplify this phenomenon. However, those findings are not equivocal. Contrasting recent research, that used multiple atmospheric [CO₂] records from the Amazon, indicates that the region’s southeast is still a carbon sink, attributing the excess of atmospheric carbon observed to emissions from the neighbouring Cerrado and Caatinga biomes. Unlike the Amazon, the Caatinga and Cerrado biomes are dryland ecosystems characterised by large fluctuations between a wet season and a very strong dry season. These tropical semi-arid ecosystems have historically been little-researched, yet they significantly contribute to inter-annual variability in the global carbon cycle.

Building on key insights gained from previous research, this PhD project will disentangle the contributions of different biomes to the atmospheric [CO₂] signals measured at multiple monitoring stations in the Amazon. That is, the contributions of the Amazon itself will be separated from those of the Caatinga and Cerrado and, to do so, special attention will be given to the larger-scale signals measured at ATTO. By integrating bottom-up Net Biome Production (NBP) estimates from Terrestrial Biosphere Models (TBMs) with atmospheric transport models, the PhD candidate will also estimate how much the Cerrado and Caatinga biomes influence the carbon budget of the Amazon. Finally, the candidate will assess the role of disturbance in shaping inter-annual variability in the net carbon exchange and budgets of all the aforementioned biomes, thus clarifying whether the Amazon’s southeastern vegetation has truly lost its carbon uptake capacity.

This project is part of the BMBF-funded ATTO-Synthesis project, an international and highly collaborative project. We seek a highly motivated candidate to work on this project. The candidate will be jointly advised by Manon Sabot (msabot@bgc-jena.mpg.de) and Santiago Botía (sbotia@bgc-jena.mpg.de), respectively of the groups Climate and Plant Ecophysiology (CAPE) and Atmosphere-biosphere Signal Attribution in the Tropics (BSAT) at the Max-Planck-Institute for Biogeochemistry in Jena. For questions about the project, please do not hesitate to contact the advisors.

Your tasks

• Gather a comprehensive dataset of disturbances (fire, land use change, etc.) and in-situ tower data
• Run/Use bottom-up models together with disturbance data
• Run atmospheric transport models and compare outputs to local measurements
• Quantify the carbon budget of tropical South America with a focus on the Amazon and its neighbouring semi-arid biomes
• Interact with other groups of the ATTO project in Brazil and Germany

Your profile

• Diploma or Master´s degree in geosciences, environmental sciences, physics, atmospheric sciences, or related disciplines
• Comfortable with statistics, mathematics, and complex systems (e.g., understanding feedback loops)
• Knowledge of or curious about the carbon cycle in South America and willing to expand your knowledge in related disciplines
• Experience with programming (Python, Julia or other languages) and modelling
• Very good written and spoken English

Our offer

The full-time position as a PhD researcher (m/f/d) is to be filled with a start in September 2025 or later. Part-time work is generally possible. The position will be evaluated and graded following the collective agreement according to TVöD Bund. The Max Planck Society (MPS) strives for gender equality and diversity. The MPS aims to increase the proportion of women in areas where they are underrepresented. Women are therefore explicitly encouraged to apply. We welcome applications from all fields. The Max Planck Society has set itself the goal of employing more severely disabled people. Applications from severely disabled persons are expressly encouraged.

Your application

Are you interested? Please send us your application with cover letter, curriculum vitae as well as names and contact information of two references summarised in a PDF file (max. 10 MB) by June 15, 2025, quoting the reference number 12/2025 by e-mail to bewerbung@bgc-jena.mpg.de or to the

Max-Planck-Institut für Biogeochemie
Personalbüro: Kennwort „PhD position 3”
Hans-Knöll-Straße 10
07745 Jena
Germany

We ask that you do not use application folders, but only submit copies, as your documents will be destroyed in accordance with data protection regulations after the application process has been completed. We look forward to receiving your application!