Michael Böttcher - Projects
BONUS-AMBER (Assessment and Modelling Baltic Ecosystem Response)
TP Groundwater impact on coastal biogeochemistry
The general aim of AMBER is the implementation and application of the Ecosystem Approach to Management (EAM) to the Baltic Sea in the face of two closely intertwined environmental threats, eutrophication and climate change. Focus is on the coastal ecosystem (CE) because it supports most of the 85 mi inhabitants of nine nations around the Baltic Sea catchment. The CE receives most human derived nutrient loads from rivers, submarine ground water discharge (SGD), atmospheric deposition, and point sources and links the land with the open Baltic Sea. The CE controls the biogeochemical transformations of P-, N- compounds (phosphate, nitrate, DON, etc.) through the close coupling between water and sediments. Furthermore, it is crucial for fish as reproduction area, nursery and grazing ground and tightly connected to the open Baltic Sea. For an optimal integrated management, the implementation and application of EAM concepts on the CE it is necessary to study in a holistic approach the link between the catchment (including groundwater) and the open Baltic Sea and how climate change will affect the river water constituents and the biogeochemistry of the coastal waters and sediments. Unfortunately it is difficult to separate the signals of climate change from the direct impact of human activity. To understand and manage the future development of CE, the separation of these signals is necessary. Hence, one of the first steps of AMBER is the separation of climate from anthropogenic signals by means of a combinatorial variation in model's boundary conditions using the output of existing regional climate change scenarios and the output of a watershed model simulating changes in land use.
WATT-III: BioGeoChemistry of Tidal Sediments
Zur Klärung des Stoffumsatzes im Wattenmeer soll die Hypothese geprüft werden, dass Ereignisse wie Planktonblüten und die damit zusammenhängende mikrobielle Aktivität die Transformation von organischem Material, Mangan (Mn) und Molybdän (Mo) in der Wassersäule und im Oberflächensediment ganz entscheidend beeinflussen. Wir postulieren, dass es beim Zusammenbruch von Phytoplanktonblüten zur Aggregatbildung durch Mikroorganismen kommt und dass die Zahl der Bakterien auf den Aggregaten während der strömungsberuhigten Phasen bei Flut und Ebbe stark zunimmt. Durch den intensiven mikrobiellen Abbau der organischen Substanz sollten anoxische Mikrozonen gebildet werden, und als Folge davon sollte es zu einer teilweisen Mn(IV)-Reduktion und einer Freisetzung von Mn(II) kommen. Gleichzeitig wird Mo in den Aggregaten fixiert und der gelösten Phase entzogen. Ein Teil der gebildeten Aggregate sedimentiert und wird auf den Wattflächen abgelagert. Die anschließende Mineralisierung der Aggregate im Sediment führt zu einer langsamen Freisetzung von Mn und Mo und einer verzögerten Abgabe in die Wassersäule. Durch mehrwöchige Intensivstudien im Freiland, mit Rolltankexperimenten, an Sedimentkernen unter definierten Bedingungen im Labor und durch Modellierung soll die Hypothese geprüft werden.
CLIMSPA - Paleogeochemical studies of marine environments during high productive and/or anoxic episodes: Inferences for processes related to global change
The collaborative effort of the project will develop a research strategy to understand processes that play a fundamental role in global climate change such as productivity fluctuations, eutrophication and the development of anoxia. Due to the complex nature of these processes, a multi-proxy approach is sought to understand the interactions among the climate subsystems, Biosphere-Geosphere-Hydrosphere. The proposed research will provide high quality geochemical data from marine archives that, in turn, will help to better understand global change, climate variability and environmental responses to climate change. Within the framework of this collaborative proposal different oceanographic and hydrographic settings (Baltic Sea, Black Sea, Mediterranean, Black shales) have been selected that cover a variety of paleoenvironments including a range of conditions as regards to productivity, biogeochemical processes and oxygenation conditions.