Overview | Energy and the Earth System | Land Surface Dynamics | The Diverse Biosphere
Overview of our Research
Stuff mixes, water flows downhill and wood burns into ashes. In the absence of other processes, sooner or later all matter would be uniformly mixed. Water would collect in the world's oceans, mountains would be eroded down to the seafloor, and wood would be burnt to ashes. These processes would transform the distribution of geochemical elements into a "dead" Earth state, with no gradients present to drive fluxes that result in global cycles of geochemical elements and no free energy would be available to “run” life.
These seemingly trivial observations highlight an underlying general direction into which any process in the Earth system evolves in time. The examples are processes that cannot be undone, or, technically speaking, they are irreversible. They happen spontaneously. This direction is understood and quantified in general terms using the fundamental theory of thermodynamics. Specifically, this is what the second law of thermodynamics tells us. The common form of this law formulates this direction in quantifiable terms, using entropy as a measure for the lack of gradients and free energy. By depleting gradients and sources of free energy, these processes are directed towards the state of thermodynamic equilibrium at which the entropy of the system is maximized. In this state, matter is well mixed and no free energy is available to perform physical work, or run chemical or metabolic reactions.
This fundamental view also applies to the geochemical processes and global cycles of Earth as well as life itself. The Earth’s state far away from a "dead" state with highly active geochemical cycling and the abundance of life appear to contradict this general direction and thus seem to violate the second law of thermodynamics. What is it about the planet Earth which allows it to be maintained so far away from the final, "dead" state of thermodynamic equilibrium? Which processes perform the physical and chemical work that separates stuff, moves water uphill, forms mountains, and produces wood out of ashes? In general terms, what creates the gradients that are required for the maintenance of global geochemical cycling?
Life has found various ways -- as reflected in its inherent diversity -- to generate and utilize sources of free energy and this has profoundly altered the environmental conditions on Earth. Many biotic effects directly affect the rates of geochemical processes, with consequences for the global cycles of carbon, water, and oxygen. How do these biotic effects alter the resulting thermodynamic state of the Earth system? To what extent is the unique thermodynamic state of Earth the result of the abundant and highly active biosphere? Which role does diversity play in the functioning of the biosphere and its ability to evolve and adapt?
In the recent part of Earth’s history, humans started to profoundly alter the Earth system. The burning of fossil fuels alters the chemical composition of the atmosphere, clearing large areas of natural vegetation for agriculture affects the exchange fluxes on land and extracting wind power from the atmosphere for electric power generation has effects on the boundary layer of the atmosphere. Do human activities bring the Earth system closer to or further away from the "dead" state of thermodynamic equilibrium?
Group Structure
The research of the “Biospheric Theory and Modelling” is organized around three focus areas:
Focus 1: Energy and the Earth System
deals with topics related to organizing principles and the role of life within the context of how energy is transformed at the planetary scale [more]
Focus 2: Dynamics of the Land Surface
includes topics related to the structure and functioning of the land surface and its exchange with the atmosphere, biosphere, and lithosphere [more]
Focus 3: The Diverse Biosphere
addresses topics that describe, model and predict the shape, diversity and functioning of the terrestrial biosphere in the context of the Earth system and human activity [more]
Funded Projects
Most of our research is curiosity driven and some elements are controversial to some extent, hence not funded by projects, but rather by the base funding provided by the Max Planck Society. We contribute and participate in these projects and initiatives:
Planetary evolution and life:
to study the potential for the origin and development of life of a planetary body. Headed by the Institute of Planetary Science of the German Aerospace Center (DLR). [more]Catchments as Organized Systems:
to provide a new framework for building hydrological models that allow a much more realistic representation of the surface and especially subsurface architecture of catchments at the lower mesoscale [more]