Max Planck Institutes and Experts

The terrestrial biosphere is an integral component of the Earth system. Are there general principles which might explain and predict the functioning of the biosphere and its interaction with the Earth system? This question is central to the work of the biospheric theory and modeling group at the Max-Planck-Institute for Biogeochemistry, and is addressed by using concepts from thermodynamics, statistical mechanics and optimality. After a brief description of the biosphere as a dissipative system, three examples are given to demonstrate the strength of these approaches.

Aerosols are of central importance for atmospheric chemistry and physics, the biosphere, climate, and public health. The airborne particles influence the Earth’s energy balance, the cycling of water and trace gases, as well as the reproduction and diseases of biological organisms. Current investigations elucidate the relevant properties and mechanisms, especially for biogenic components.

Amazonian floodplain forests are endangered due to their easy accessibility, nutrient-rich soils and richness in natural resources. Information on diversity, dynamics and tree growth in relation to environmental factors is the basis for the development of sustainable management concepts to guarantee their multiple ecological functions and at the same time the supply of natural resources for the local populations.

The evolution and stability of the meridional overturning circulation in the Atlantic under global warming conditions, its observational characteristics, and the detectability of such anthropogenic changes have been investigated with the MPI-M climate model. For realistic projections of the climate evolution in the 21st century, the model indicates a reduction of 30-42%, but no total breakdown of the overturning circulation. Natural variability on time scales of days to decades requires long-term observations in the Atlantic to detect a potential decrease.

The Nutrient Group was established in May 2005 as an independent junior research group funded by the Max Planck Society. Research focuses on processes that control nutrient nitrogen availability in past and present marine environments. Specifically, environmental regulation of these processes and their effects on global biogeochemical cycles are investigated. As these cycling processes are typcially mediated by microorganisms, combinations of newly developed geochemical, microbiological and molecular-ecological techniques are applied in these studies. One of the current projects of the Nutrient Group is an elucidation on the role of the recently described anaerobic ammonium oxidation (anammox) within the oceanic nitrogen cycle.