Biosphere dynamics
In our research group we are interested in the interaction of the marine and terrestrial carbon cycle with global climate. We investigate changes in the marine carbon cycle by applying the output of several Miocene ocean circulation sensitivity experiments to a marine carbon cycle model (HAMOCC2s, Heinze and Maier-Reimer 1999). This model considers geochemical tracers and biogenic particulate matter in the water column as well as in the bioturbated sediment. Using 13C among others as model output variable, the geochemical simulations provide a new framework to interpret Neogene paleoenvironmental data.
The terrestrial biosphere is not only determined by climate but it has always been impacted by humans, by means of land use or deforestation. At the same time, the biosphere itself affects the local and even global climate. To allow for predictions of future changes in the ecosphere and its interaction with climate, it is necessary to better understand the behaviour of the biosphere as part of the global climate system in the past. Biogeophysical feedback from the land biosphere has been investigated in a number of paleoclimate modeling studies. During interglacials, for example, warmer and wetter than present summers in the northern hemisphere resulted in a northward expansion of boreal forests and a retreat of subtropical deserts. These land cover changes altered the surface albedo and thus amplified the climatic change. However, to find the reasons for past changes of e.g. atmospheric trace gases as depicted in the ice-core record, a more detailed understanding of biogeochemical processes, on land as well as in the ocean, and their proper description in Earth-system models is inevitable. This comprises all different time scales from minutes (e.g. stomatal response) to hundreds of years (e.g. forest dynamics) and even millions of years when the evolution of the biosphere together with the climate is considered. The high northern latitudes are one of the key area with respect to ecological changes.
Examples:
- Simulation of the global bio-geophysical interactions during the Last Glacial Maximum: pdf (672 KB)
- Carbon cycle, vegetation, and climate dynamics:Experiments with the CLIMBER-2 model: pdf (1,2 MB)
- Simulation of an abrupt change in Saharan vegetation: pdf (136 KB)
- Climate Change in Northern Africa: The Past is Not the Future: description pdf (244 KB)
- The Influence of Vegetation–Atmosphere–Ocean Interaction on Climate During the Mid-Holocene: pdf (400 KB)
- Deep ocean circulation and climate during the MioceneDeep ocean circulation and climate during the Miocene: GCM experiments applied to a marine carbon cycle model. Poster (684 KB)
Further information, for example: