Our Research
Our research aims to understand how the whole Earth functions as one complex system that is strongly shaped by interactions, what the role of life is within this system, and how humans alter it.
It is based around two central themes:
- The first theme is to use and apply the physical theory of non-equilibrium thermodynamics to Earth system processes and interactions, specifically regarding the generation, dissipation and conversions of free energy, the part of energy that is able to perform work. If it were not for continuous work being performed by Earth system processes, motion, chemical reactions, and dynamics would come to a halt. In our research we aim to understand how this free energy is generated within the Earth system, from heat to motion to geochemical cycling, and how life contributes to, interacts with, and alters these transformations. Recent examples for this research are:
- How does life affect the Earth’s interior dynamics?
- What are the limits to wind power as a renewable energy resource?
- How was the chemical free energy generated to drive the emergence of life?
- The second theme is biodiversity as a central concept to describe life and its effect of biogeochemical cycling. One of the fundamental aspects of life is that it is inherently diverse. It has many ways to “do things”, and it is able to adapt and evolve to environmental change. In our research, we aim to account for this complexity by using optimality approaches and approaches that are able to represent aspects of diversity. Examples of our recent research are:
- How is vegetation biodiversity related to climate?
- Which role do geologic processes, climate and vegetation play in cycling phosphorus?
Our Approach
We work mostly with theory, simple models and more complex, numerical simulation models, focussing mostly at the large- to planetary scale. We do not do field or laboratory work. Theoretical work focuses mostly on how thermodynamics is applied to Earth system processes, while numerical simulation models, such as models of the climate system or terrestrial vegetation, provide our testing grounds for our research. In our group, we develop the JEna DIversity (JEDI) model, a global vegetation model that explicitly represents diversity of vegetation functioning.
Our Group
We are a so-called Max Planck Research Group (MPRG) and as such an independent unit hosted within the Max Planck Institute for Biogeochemistry. Besides the group leader, Dr. Axel Kleidon, the group currently consists of 3 postdocs, 7 doctoral students, one master student, and support staff (partially shared).
Our Funding
Most of the group’s activity is funded by the Max Planck Society, a non-profit organization funded primarily by German federal research funds and which is devoted to conduct basic research. This source of funding with ʻno strings attachedʼ allows us to perform research without prejudices, preconceptions, or personal, financial, or political conflicts of interest. Because our research is often high risk and goes against the established wisdoms and preconceptions in the field, the base funding that we receive from the Max Planck Society provides an ideal work environment to perform our research.
>> more on our funding sources
>> more on the Max Planck Society
>> more on the Max Planck Institute for Biogeochemistry
Recent Publications
Submitted/In discussion:
A Kleidon, M Renner, Thermodynamic limits of hydrologic cycling within the Earth system: concepts, estimates and implications, Hydrol. Earth Syst. Sci. Discuss., 10, 3187-3236, 2013.
E Simoncini, N Virgo, A Kleidon, Quantifying drivers of chemical disequilibrium in the Earth's atmosphere, Earth Syst. Dynam. Discuss., 3, 1287-1320, 2012
E Zehe, T Blume, A Kleidon, U Ehret, U Scherer, M Westhoff, Connected flow paths as first order control on critical zone water flows: coincidence or self-organized optimality? Hydrology and Earth System Sciences Discussion, 9, 10595-10655, 2012.
R Pavlick, D T Drewry, K Bohn, B Reu, A Kleidon, The Jena Diversity-Dynamic Global Vegetation Model (JeDi-DGVM): a diverse approach to representing terrestrial biogeography and biogeochemistry based on plant functional trade-offs. Biogeosciences Discussion, 9, 4627-4726.
2013:
A Kleidon, E Zehe, U Ehret, U Scherer, Earth system dynamics as the consequence of the second law: Maximum power limits, dissipative structures, and planetary interactions. in: R C Dewar, C Lineweaver, R Niven, K Regenauer-Lieb (eds) Beyond the second law: entropy production and non-equilibrium systems, Springer, accepted.
A Kleidon, E Zehe, U Ehret, U Scherer, Thermodynamics, maximum power, and the dynamics of preferential river flow structures on continents. Hydrology and Earth System Sciences, 17, 225-251, 2013.
2012:
A Kleidon, E Zehe, H Lin, Thermodynamics of the Critical Zone and its relevance to hydropedology. in: H Lin (ed) Hydropedology: Synergistic Integration of Soil Science and Hydrology, Academic Press, Elsevier, 243-281.
F Gans, L M Miller, A Kleidon, The problem of the second wind turbine – a note on a common but flawed wind power estimation method, Earth Syst. Dynam., 3, 79-86, 2012
A Kleidon (2012) Was leistet die Erde? Thermodynamische Grenzen des Erdsystems und deren Bedeutung für eine nachhaltige Zukunft, Physik in unserer Zeit, 3/2012, 136-144.
A. Kleidon (2012) How does the earth system generate and maintain thermodynamic disequilibrium and what does it imply for the future of the planet?, Phil Trans A, 370: 1012-1040.
2011:
E. Simoncini, M.J. Russell, A. Kleidon , (2011) Modeling free energy availability from Hadean Hydrothermal Systems to the first metabolism Orig. Life and Evol. Biosph.
L Miller, F Gans, A Kleidon, (2011) Jet stream wind power as a renewable energy resource: little power, big impacts in Earth System Dynamics, 2, pp. 201-212.
A Kleidon, F Gans, L Miller, R Pavlick, (2011) Sonne, Wind und Wellen -- Natürliche Grenzen erneuerbarer Energien im Erdsystem Δ, in: Beckmann, Hurtado (eds.), Kraftwerkstechnik, Band 3, TK Verlag, Neuruppin, pp. 463-470.
Porada, P., Kleidon, A., Schymanski, S. J., (2011) Entropy production of soil hydrological processes and its maximisation, Earth Syst. Dynam., 2, 179-190, doi:10.5194/esd-2-179-2011
B. Reu, S. Zaehle, R. Proulx, K. Bohn, A. Kleidon, R. Pavlick, S. Schmidtlein (2011) The role of plant functional trade-offs for biodiversity changes and biome shifts under scenarios of global climatic change, Biogeosciences., 8, 1255-1266.
Brunsell, N. A., Schymanski, S. J., Kleidon, A. (2011) Quantifying the thermodynamic entropy budget of the land surface: is this useful?, Earth Syst. Dynam., 2, 87-103, doi:10.5194/esd-2-87-2011
J.G. Dyke, F. Gans, A. Kleidon (2011) Towards understanding how surface life can affect interior geological processes: a non-equilibrium thermodynamics approach, Earth Syst. Dynam., 2, 139-160. doi:10.5194/esd-2-139-2011
K. Bohn, J. G. Dyke, R. Pavlick, B. Reineking, B. Reu, A. Kleidon (2011) The relative importance of seed competition, resource competition and perturbations on community structure, Biogeosciences, 8, 1107-1120. doi:10.5194/bg-8-1107-2011
S. Arens, A. Kleidon (2011) Eco-hydrological versus supply-limited weathering regimes and the potential for biotic enhancement of weathering at the global scale, Applied Geochemistry, 26, S274-S278. doi:10.1016/j.apgeochem.2011.03.079
L.M. Miller, F. Gans, A. Kleidon (2011) Estimating maximum global land surface wind power extractability and associated climatic consequences, Earth Syst. Dynam. 2. 1-12, doi:10.5194/esd-2-1-2011.
2010:
C Buendía, A Kleidon, and A Porporato, 2010. The role of tectonic uplift, climate, and vegetation in the long-term terrestrial phosphorous cycle, Biogeosciences, 7, 2025-2038.
DT Drewry, P Kumar, S Long, C Bernacchi, X-Z Liang, M Sivapalan, 2010. Ecohydrological responses of dense canopies to environmental variability. 1. Interplay between vertical structure and photosynthetic pathway. Journal of Geophysical Research, Vol. 115, G04022, doi:10.1029/2010JG001340.
DT Drewry, P Kumar, S Long, C Bernacchi, X-Z Liang, M Sivapalan, 2010. Ecohydrological responses of dense canopies to environmental variability. 2. Role of acclimation under elevated CO2. Journal of Geophysical Research, Vol. 115, G04023, doi:10.1029/2010JG001341.
J Dyke, A Kleidon, 2010. The Maximum Entropy Production Principle: Its Theoretical Foundations and Applications to the Earth System, Entropy, 12(3), 613--630.
A Kleidon, 2010. Life as the major driver of planetary geochemical disequilibrium. Reply to comments on "Life, hierarchy, and the thermodynamic machinery of planet Earth", Physics of Life Reviews, 7, 473-476.
A Kleidon, 2010. Life, hierarchy, and the thermodynamic machinery of planet Earth, Physics of Life Reviews, 7, 424-460.
A Kleidon, 2010. Non-equilibrium thermodynamics, maximum entropy production and Earth-system evolution, Philosophical Transactions of the Royal Society A, 368: 181-196.
A Kleidon, Y Malhi, and PM Cox, 2010. Maximum entropy production in environmental and ecological systems, Philosophical Transactions of the Royal Society B, 365, 1297-1302.
A Kleidon, 2010. A basic introduction to the thermodynamics of the Earth system far from equilibrium and maximum entropy production, Philosophical Transactions of the Royal Society B, 365, 1303-1315.
P Porada, 2010. Thesis: Entropy Budget of the Soil Hydrological Cycle. Supervisors: Prof. Dr. W Lucht, Humboldt University Berlin, Dr. A Kleidon, MPI Biogeochemistry Jena.
B. Reu, R. Proulx, K. Bohn, J. Dyke, A. Kleidon, R. Pavlick, S. Schmidtlein (2010) The role of climate and plant functional trade-offs in shaping global biome and biodiversity patterns. Global Ecology and Biogeography, 20: 570–581. doi: 10.1111/j.1466-8238.2010.00621.x
B. Schaefli, C. J. Harman, M. Sivapalan, and S. J. Schymanski, 2010. Hydrologic predictions in a changing environment: behavioral modeling, Hydrol. Earth Syst. Sci. Discuss., 7, 7779-7808, 2010. doi:10.5194/hessd-7-7779-2010
E. Simoncini, A. Kleidon, E. Gallori, 2010. The Emergence of Life: Thermodynamics of Chemical Free Energy Generation in Off - Axis Hydrothermal Vent Systems and its Consequences for Compartmentalization and Life's Origins, J. of Cosmology, 10, 3325 - 3344.
SJ Schymanski, A Kleidon, M Stieglitz, and J Narula, 2010. Maximum entropy production allows a simple representation of heterogeneity in semiarid ecosystems, Philosophical Transactions of the Royal Society B, 365, 1449-1455.
X Xu, A Kleidon, L Miller, S Wang, L Wang, and G Dong, 2010. Late Quaternary glaciation in the Tianshan and implications for palaeoclimatic change: a review, Boreas, 39(2): 215-232.
Contact Us:
- Want to visit us? Let us know. Here is some information of how to get around Jena and how to find us (long version with public transport information).
- Interested in internships, graduate research, or postdoc opportunities? Contact us.
- Contact: Dr. Axel Kleidon, Max-Planck-Institute for Biogeochemistry, Hans-Knoell-Str. 10, 07745 Jena, Germany. Ph: +49-3641-576217. E-mail: axel.kleidon AT bgc-jena DOT mpg DOT de.
