With the setup of the Terrestrial Observatories and the development of new sensing methods, unprecedented information about the status of and fluxes within terrestrial systems will become available, e.g. groundwater recharge, discharge of water by rivers, leaching of chemicals from the soil surface to the groundwater, turn-over of soil organic matter, emission of green house gases from the soil into the atmosphere. These processes are subject to change due to land-use, land management and climate change. Terrestrial system models are useful tools to make prognoses of the reaction of these systems to changing boundary conditions. The nested hierarchy approach combined with real-time measurements and spatially continuous non-invasive measurement techniques of TERENO represents an excellent basis for the development and the validation of integrated modelling approaches at the regional scale as well as scaling approaches and data assimilation techniques.

The CT Integrated Modelling will focus on the following tasks:

• Integrated Modelling
• Scaling issues
• Data assimilation
• Uncertainty issues

Members

• Sabine Attinger (UFZ)
• Olaf Kolditz (UFZ)
• Harald Kunstmann (KIT)
• Harrie-Jan Hendricks-Franssen (FZJ)
• Luis Samaniego-Eguiguren (UFZ)
• Jan Vanderborght (FZJ)

The CT Biosphere will focus on the investigation of the interactions between biodiversity and processes related to hydrology, atmosphere and climate which are part of and altered by global change. Biodiversity and its function will be assessed in the regional, landscape and local context along broad environmental gradients as a basis for understanding impacts on and sustainable management of biodiversity under global change. Moreover, we will include external factors affecting biodiversity and the consequences of biodiversity change.

We propose to use the DPSIR (Driver - Pressure - State - Impact - Response; see Wieringa 1999, Tapio & Willamo 2008) scheme developed by the EEA as a basic framework to develop activities in research and monitoring. Within this framework potential targets of CT Biosphere are Pressure, State and Impact. Climate change and land use change will be the central pressures under investigation, causing a certain state of biotic and abiotic environmental conditions which have an impact on communities (change or loss of biodiversity) and the availability and sustainability of ecosystem services (e.g. pollination, nutrient cycling). The CT Biosphere will focus on the same set of pressures investigated in different systems (forest, grasslands, agro-ecosystems) and scales (from site to landscape). The used indicators within TERENO should be the same or closely related aiming at ecosystem services.

In order to increase synergistic effects and to be compatible to related programs and projects, it is advisable to tune parameters, indicators and the corresponding methods dealing with state and impact. This should be done explicitly with (a) the set of recommended parameters and methods developed by LTER-Europe (network of Long Term Ecosystem Research sites across Europe) and the methodological approach performed by the (b) biodiversity exploratories of the DFG. Moreover, we will consider (c) SEBI 2010 recommendations.

Due to the different foci of the participating Helmholtz centres and the manpower-demanding tasks related to CT Biosphere, we will take a simple and feasible approach adjusted to the resources of the centres. Basic tasks will be performed by all centres while some advanced tasks will only be carried by single centres. The common ground will be the aspects of land use change (forests, agro-forest, and energy plants) affecting nutrient cycling within agricultures and the stored soil carbon. Climate change can only be tackled using long-term data and long-term experiments which are the basis for modelling. This issue is covered by different approaches:

• Helmholtz Centre Munich: simulation of global warming by experimental soil heating
• UFZ: modelling of prospective species distributions; measurements of ring width and of isotope signals of carbon, oxygen and hydrogen in tree rings (recent state and temporal dynamics)

The selected parameters and indicators for state and impacts need to fulfil the following requirements:

• Sensitive to the selected pressures
• Interactions between indicators, getting most out of it by combining indicators
• Suitable for species pool analysis etc.

To spread the base for common data without a specific need for expert knowledge and to minimize the manpower passive sampling methods will be applied for selected issues.

Members

• Stefan Klotz (UFZ)
• Mark Frenzel (UFZ)
• Angela Lausch (UFZ)

The CT Hydrosphere concentrates on the investigation of regional hydrological effects of Climate Change and landuse change on the regional hydrology. Change of climatic conditions (precipitation, temperature) as well as change in land use and their impact on water and matter fluxes are the key factors for the quantitative and qualitative status of freshwater resources.

A better knowledge of the regional differentiation of the described hydrological impacts is a crucial basis for future water resources management. The four selected TERENO catchments offer the opportunity to cover nearly the complete span of variation in projected climate change in Germany. Detailed observation of the hydrological cycle in these regions is the basis for a high quality multi-temporal multi-scale database for hydrological and terrestrial modelling in order to assess long-term changes in German ecosystems (natural, agricultural, and forested).

The following tasks are planned:

• Establishment of intensive soil moisture monitoring sites collocated to climate towers for coordinated observation. Measurements will be made at several depths in the soil profile, where feasible down to the water table. In addition to the multi-depth soil moisture monitoring sites, wireless sensor networks will be established at the sub-catchment scale. The wireless sensor network technology has the potential to reveal fine-grained, dynamic changes in soil moisture. Additionally remote sensing to measure soil water content variations over large regions will be applied. The proposed network of soil moisture monitoring should have a sufficient density and appropriate placement in order to capture the regional gradients (climate, urban-rural) and the inherent spatial-temporal variability (soil and topographic heterogeneity).
• River discharge monitoring. In order to get spatially distributed information about river discharge rates, the full Observatory needs to be partitioned into a nested set of sub-catchments that will span distinct assemblages of hydrologic features and several orders of magnitude in drainage area. Detailed measurements and characterization of smaller, focal catchments will be embedded within progressively larger catchments, allowing critical evaluation and development of hydrologic scaling strategies.
• Investigation of the spatiotemporal variability of groundwater recharge, study of the groundwater flow systems and the related transport of solutes.
• Water quality measurements. These will be intimately connected with the monitoring of river discharge and groundwater recharge to estimate matter fluxes. Monitoring stations will be established at main branches of the river network that enable a continuous and event controlled sampling of water samples.
• Environmental tracer studies will be used for process studies of the hydrogeologic systems and are thus complementary to the physical measurements. Additionally, general features of water quality will be automatically measured with high temporal resolution (see Tab. 10.2). Additionally, in urban areas specific pollutants will be monitored, e.g. Xenobiotika, bacterial toxins, pharmaceuticals etc.

Members

• Steffen Zacharias (UFZ)
• Heye Bogena (FZJ)
• Michael Rode (UFZ)
• Luis Samaniego-Eguiguren (UFZ)
• Harald Kunstmann (UFZ)
• Theresa Blume (GFZ)
• Harald Kunstmann (KIT)

SOILCan

Meetings

The CT Pedosphere concentrates on the interactions of the pedosphere with biosphere, lithosphere, hydrosphere and atmosphere with a special focus on process and structure based functionality. In close collaboration with CT Atmosphere the interactions between of atmosphere and pedosphere will be investigated in relation of water, C and N trace gases, and other matter fluxes, storage changes as well as sink/source dynamics. Data collected by intensive monitoring will be extremely valuable to be used in modelling approaches allowing extrapolating and/ or up-scale (soil) ecosystem processes and related characteristics from the plot scale of intensive test sites to landscape or regional scale.

Soil functions and processes are characterised by experimental approaches and accompanying mathematical modelling on various spatial (micro-scale, macro-scale, lysimeter, field-plot) and time scales with the aim of being able to control and assess matter fluxes and concentrations in biogeosystems. The knowledge of spatial heterogeneity and interaction of processes on local scale is an important challenge to predict the functioning of biogeosystems at larger scales such as the field, farm and catchment scale.

The CT Pedosphere focuses on the scale transition between point/pedon and regional scale. The ultimate goal is to develop an 'effective' one-dimensional approach including the inherent non-linear behaviour of different flux components, especially the onset of vertical preferential flow and lateral interflow and surface runoff. The required parameterization of the unsaturated zone will be based on direct structural soil properties (in contrast to the concept of multi-domain models based on fitted parameters). It will provide residence and travel time distribution within the unsaturated zone in response to external forcing by precipitation. A quantitative understanding of water and matter fluxes through terrestrial systems requires a hierarchical approach because of its hierarchical organization across many spatial scales. The CT Pedology will contribute to the following topics:

• Soil organic carbon pool sizes, fluxes, stabilities and reactivities
• Use of radiolabelled crop residues offers a unique possibility to characterise shifts of carbon stocks and fluxes against the large pool of carbon present in the soil.
• Use of stable isotope labelled crop residues or even plant root exsudates will resolve the chemical structure in various pools. Further, sophisticated respirometric methods will be used to assess the mineralization of organic carbon associated with different soils fractions (Corg - pools).
• In the frame of the climate feedback concept a lysimeter network will be establish (SOILCan) to anticipate a climate change. Lysimeters filled along a temperature and rainfall gradient will be transferred to intensive measurement fields with warmer and dryer conditions than the origin sites. The dryer and warmer conditions will affect the water household, C and N cycles of the lysimeter soil monoliths as well as biodiversity.
• Establishment of intensive monitoring of total soil GHG exchange at sites collocated to climate and EC towers for coordinated observation.
• Dry and wet deposition monitoring of selected test sites.
• Monitoring of soil physical properties (density, texture, etc.).
• Archiving of soil samples of the different intensive test sites
• At the Leipzig-Halle Observatory a specific concept for the in-situ monitoring 'Vadose Zone Monitoring Systems' (VZMS) for agricultural sites
• After geophysical exploration and pedological survey the dynamics of water, carbon, nitrogen and other elements as well as exchange processes with the atmosphere and hydrosphere will be investigated at representative sites in the observatories (catchments).
• Screening of soil chemical parameters, especially nutrients, pesticides and xenobiotika
• Characterisation of SOM in dependence of land use changes and source /sink dynamics of environmentally important C and N trace gases.
• Compilation of soil and area conditions resulting from former land use.
• Integrated modelling of SOM turnover in combination with water and energy fluxes in the soil
• Inversion and validation of models using point measurements of SOM characteristics and CO2 fluxes

Members

• Thomas Pütz (FZJ)
• Heye Bogena (FZJ)
• Steffen Zacharias (UFZ)
• Hans-Jörg Vogel (UFZ)
• Ralf Kiese (KIT)
• Theresa Blume (GFZ)
• Erik Borg (DLR)