Werner Aeschbach

Universität Heidelberg · Institute of Environmental Physics

Noble gases were used as proxies in Arctic Ocean samples to constrain the physical processes (such as bubble injection and solute rejection from sea ice) leading to the formation of different waters in the Arctic. The constraints allow for the "correction" of input functions of other tracers, such as CFC-12 and SF6, which have previously been assum...

Understanding the hydrodynamics of meromictic gas-rich lakes is crucial for predicting and preventing hazards posed by limnic eruptions. In this work, the quantum technological argon trap trace analysis (ArTTA) method was applied for the first time in lake water. ArTTA can resolve very low isotopic abundances of about 10-16, requiring only a few li...

Understanding the age distribution of groundwater can provide information on both the recharge history as well as the geochemical evolution of groundwater flow systems. Of the few candidates available that can be used to date old groundwater, ⁸¹Kr shows the most promise because its input function is constant through time and there are less sources...

Hydrogen ($\delta$2H) and oxygen ($\delta$18O) isotopes of water extracted from speleothem fluid inclusions are important proxies used for paleoclimate reconstruction. In our study we use a cavity ring-down laser spectroscopy system for analysis and modified the approach of Affolter et al. (2014) for sample extraction. The method is based on crushi...

In the scope of assessing aquifer systems in areas where freshwater is scarce, estimation of transit times is a vital step to quantify the effect of groundwater abstraction. Transit time distributions of different shapes, mean residence times, and contributions are used to represent the hydrogeological conditions in aquifer systems and are typicall...

In the scope of assessing aquifer systems in areas where freshwater is scarce, estimation of transit times is a vital step to quantify the effect of groundwater abstraction. Transit time distributions of different shapes, mean residence times, and contributions are used to represent the hydrogeological conditions in aquifer systems and are typicall...

Due to their biological and chemical inertness, noble gases in natural waters are widely used to trace natural waters and to determine ambient temperature conditions during the last intensive contact with the atmosphere (equilibration). Noble gas solubilities are strong functions of temperature, with higher temperatures resulting in lower concentra...

Energie ist eine Erhaltungsgröße und kann weder erzeugt noch zerstört werden, allerdings kann Energie mehr- oder weniger „wertvolle“ Formen annehmen, etwa elektrische Energie (wertvoll) oder Wärmeenergie (weniger wertvoll). Die Verfügbarkeit von Energie prägt unser modernes Leben, ihre Bereitstellung durch Verbrennung fossiler Brenn-stoffe erzeugt...

Die Physik (von lat. physica) bedeutet „Naturlehre“, sie beschäftigt sich dementsprechend mit der wissenschaftlichen Erforschung und quantitativen Beschreibung von Naturerscheinungen. Die heutige Physik ist eine hochdifferenzierte Wissenschaft, sie hat sich in vielen ihrer Sparten Erscheinungen zugewandt, die mit unseren Sinnen nicht direkt wahrneh...

The Ledo-Paniselian aquifer in Belgium has been proposed to offer unique opportunities to study groundwater recharge and flow in periglacial conditions during the Last Glacial Maximum (LGM), due to its location in the permanent permafrost area, south of the ice sheet at that time. A palaeoclimatic record had been set up previously for this aquifer,...

Knowing the age distribution of water abstracted from public water supply wells helps to ensure customer trust in drinking water sources and underpin predictions of water quality evolution. We sampled the mixed water of 39 large public supply well fields for major ion chemistry, ³H, ³He, ¹⁸O, ²H, ¹⁴CDIC, ¹³CDIC and noble gases and determined the No...

We review our current understanding of groundwater flow history in the northern part of the Baltic Artesian Basin (BAB) from the end of the Late Pleistocene to current conditions based on the hydrogeological studies carried out in 2012–2020 by the Department of Geology, Tallinn University of Technology and its partners. Hydrogeochemical data and...

The magnitude of global cooling during the Last Glacial Maximum (LGM, the coldest multimillennial interval of the last glacial period) is an important constraint for evaluating estimates of Earth’s climate sensitivity. Reliable LGM temperatures come from high-latitude ice cores, but substantial disagreement exists between proxy records in the low l...

Lake Kivu, located on the border of Rwanda and the Democratic Republic of Congo, is a very peculiar lake in several aspects. The meromictic lake shows a vertical stratification dominated by high salt concentrations of up to 6 ‰ resulting in a very thick monimolimnion of 420 m (max depth ~492 m). This extremely large non mixing part of the lake func...

Cities are particularly sensitive to the effects of climate change, causing an increasing incidence of heat waves. Extreme temperatures can impair the use of public spaces in cities, as heat stress endangers human well-being and health. Identifying suitable adaptation measures to maintain the full functionality of public spaces requires a multidime...

The time that water takes to travel through the terrestrial hydrological cycle and the critical zone is of great interest in Earth system sciences with broad implications for water quality and quantity. Most water age studies to date have focused on individual compartments (or sub-disciplines) of the hydrological cycle such as the unsaturated or sa...

Understanding the mechanisms of groundwater recharge and flow in periglacial environments remains enigmatic. Methane releases from melting permafrost in a warming world are a hot topic in contemporary climate research. Noble gas analyses have been proposed to study methane-driven degassing in lakes as well as in permafrost terrains. The Ledo-Panise...

Significance Alpine summit glaciers have a characteristic age range between 100 and 1,000 years. Reliable dating is the key to access this valuable environmental archive, including the Little Ice Age. Glacier ice contains past air and thus also the rare radioisotope ³⁹ Ar, uniquely suitable as an age tracer for this time span. Only argon trap trace...

The Heidelberg Argon Trap Trace Analysis (ArTTA) apparatus applies quantum optical methods to establish an ultra-sensitive detection method for the radioisotope 39Ar, which, with a half-life of 269 years, serves as a unique tracer for dating of environmental samples. The ratio of 39Ar to Ar in fresh air is 10−16. To distinguish the isotope of inter...

The Ordovician-Cambrian aquifer system in the northern Baltic Artesian Basin contains glacial palaeogroundwater that originates from the Scandinavian Ice Sheet that covered the study area in the Pleistocene. Previously, no absolute dating of this palaeogroundwater has been attempted. In this multi-tracer study, we use ³H, ¹⁴C, ⁴He and stable isotop...

Groundwater in the Cambrian-Vendian aquifer system in Estonia is characterised by the most depleted isotopic composition known in Europe (δ18O down to -23‰). The water most likely originates from glacial meltwater recharge from the Fennoscandian Ice Sheet in the Pleistocene. The aquifer system is characterised by relative high methane concentration...

The Viimsi peninsula is located north-east of Tallinn, capital of Estonia. The Cambrian-Vendian (Cm-V) aquifer system is a sole source of drinking water in the area. Historically, the groundwater exploitation has led to freshening of groundwater in the peninsula, but in recent years an increase in chloride concentrations and enrichment in δ18O valu...

Ocean ventilation is the integrated effect of various processes that exchange surface properties with the ocean interior and is essential for oxygen supply, storage of anthropogenic carbon and the heat budget of the ocean, for instance. Current observational methods utilise transient tracers, e.g. tritium, SF6, CFCs and 14C. However, their dating r...

Radiometric dating with 39Ar covers a unique timespan and offers key advances in interpreting environmental archives of the last millennium. Although this tracer has been acknowledged for decades, studies so far have been limited by the low abundance and radioactivity, thus requiring huge sample sizes. Atom Trap Trace Analysis, an application of te...

Ocean ventilation is the integrated effect of various processes that propagate surface properties to the ocean interior. Its precise understanding is the prerequisite for addressing essential questions such as oxygen supply, the storage of anthropogenic carbon and the heat budget of the ocean. Currently employed observational methods to infer venti...

In Germany electricity and heat production from hydrogeothermal energy use is restricted to the northern German Basin, the Upper Rhine Graben (URG) and the Molasse Basin. Cost-effective methods are desirable in hydrogeothermal exploration in optimizing locations for utilizing renewable geothermal energy. The present study investigate if the Sr meth...

In this article we present the software PANGA which is a new open-source tool for the evaluation of noble gas data from (ground)water samples. In addition to most of the features of traditionally used software like NOBLE, it includes among others easy-to-use methods for Monte Carlo simulations and analyses, as well as support for newer excess air m...

Noble gas radioisotopes are ideal environmental tracers because of their chemical inertness. In particular, 39Ar is of great importance as it is the only tracer covering the age range of 50 to 1000 years. However, measuring the 39Ar/40Ar ratio is challenging due to an extremely low isotopic abundance in the order of 10-16 and a long half-life of 26...

Analyses for 81Kr and noble gases on groundwater from the deepest aquifer system of the Baltic Artesian Basin (BAB) were performed to determine groundwater ages and uncover the flow dynamics of the system on a timescale of several hundred thousand years. We find that the system is controlled by mixing of three distinct water masses: Interglacial or...

⁸⁷Sr/⁸⁶Sr ratios were used as a tracer of fault-controlled fluid ascent into shallow aquifers at the Western Boundary Fault (WBF) of the northern upper Rhine Graben in Germany, a major rift system of the European continent. An excellent panoramic image of the eastern and western rift shoulders of the northern Upper Rhine Graben was taken by Jörg Ni...

Strontium isotopic ratios are important tracers of hydrological processes such as water-rock interaction and the detection of the ascent of deep fluids at hydraulically active faults. The ⁸⁷Sr/⁸⁶Sr ratios were measured in shallow and deep aquifers (n=19) and thermal water at the Eastern Boundary Fault (EBF) of the intracontinental rift system, the...

The present study of thermal water from Bad Bellingen, Steinenstadt, Bad Krozingen, Mooswald, and Weinheim located in the Upper Rhine Graben, the largest rift zone in Europe (Cenozoic Rift System active until the present - most recently, a magnitude 4.7 earthquake occurred at a depth of 11 km in the border region of Switzerland, France, and Germany...

The Pliocene and Quaternary sediments of the Upper Rhine Graben of the three riparian states Switzerland, France and Germany contain the most important groundwater resources of Central Europe. The Cenozoic rift system remains active today. Most recently, a magnitude 4.7 earthquake occurred at a depth of 11 km in the border region of Switzerland,...

87Sr/86Sr ratios in shallow and deep aquifers from the southern Upper Rhine Graben, Germany.

Fault zones are hydraulic conduits connecting shallow and deep geological environments. 87Sr/86Sr ratios and Sr contents as tracers of fault-controlled fluid ascent into shallow aquifers at the Eastern Boundary Fault (Heidelberg Basin, northern Upper Rhine Graben, Germany). Highly variable Sr ratios and low Sr contents in shallow and deep aquife...

From compositional relationships between major chemical components of thermal water it is suggested that Jurassic seawater is preserved as marine paleo porewater in the sediment (He et al. 1999). However, Sr isotopic composition and Sr contents of thermal water from Bad Bellingen are indistinguishable from modern seawater (see figure). Jurassic se...

87Sr/86Sr ratios have been used as a tracer of fault-controlled fluid ascent into shallow aquifers at the Western Boundary Fault of the northern upper Rhine Graben in Germany, a major rift system of the European continent. The Strontium isotope ratios are important tracers of hydrological processes such as water-rock interaction and groundwater mix...

The TRACE project, funded by the Federal Ministry for Economic Affairs and Energy (funding code FKZ: 0325390), presents a low-cost strategy for characterizing deep hydrogeothermal reservoirs using a combination of methods from hydrogeochemistry and isotope geochemistry on fluid samples mainly taken from shallow groundwater wells. The main goal is t...

Multiple age tracers were measured to estimate groundwater residence times in the regional aquifer system underlying southwestern Oman. This area, known as the Najd, is one of the most arid areas in the world and is planned to be the main agricultural center of the Sultanate of Oman in the near future. The three isotopic age tracers ⁴He, ¹⁴C and ³⁶...

Conditions prevailing in regions of deep water formation imprint their signature in the concentrations of dissolved noble gases, which are conserved in the deep ocean. Such “recharge conditions” including temperature, salinity, and interactions with sea ice are important in view of ocean-atmosphere CO2 partitioning. Noble gases, especially the temp...

In the scope of the investigations of TRACE, groundwaters as well as thermal waters of three sites in the Upper Rhine Graben were characterized in detail and modelled with respect to their formation. The shallow groundwater is characterized by low mineralization (< 1 g/l), calcite dissolution and pyrite oxidation in the quaternary aquifer. Using th...

Dissolved helium concentrations and 3He/4He ratios were measured for 18 groundwater samples collected from the Quaternary confined aquifers in the North China Plain (NCP). The dissolved helium concentrations ranged from 1 × 10-7 to 1 × 10-6 cm3STP·g-1 in the 14 samples from the central plain, but was approximately two orders of magnitude higher, be...

Azraq Oasis in the eastern Jordanian desert is an important freshwater resource of the country. Shallow groundwater reserves are heavily exploited since the 1980s and in consequence the groundwater table dropped significantly. Furthermore, some wells of the major well field drilled into the shallow aquifer show an increasing mineralization over the...

Combined strontium isotope ratios, Sr and Li concentrations of the dissolved load of near surface groundwater and springs are important tracers of hydrological processes such as groundwater mixing in the vicinity of active faults. Our results demonstrate that the western main fault of the upper Rhine Graben is hydraulically active and a preferenti...

Helium isotopes were applied to identify possible imprints of mantle derived fluids in shallow groundwater of the Upper Rhine Graben (Germany). Samples from the shallow aquifer at Groß-Gerau (western main fault) show an impact of mantle derived fluids revealed by 3He/4He isotope analyses, correlating with Sr isotope data as well as an increase in s...

87Sr/86Sr Systematics and Li of Shallow Groundwaters and Springs at the Western Main Fault of the Northern Upper Rhine Graben

Large-scale geothermal energy production relies on extensive characterization of the target fault system: its spatial location as well as its hydraulic permeability. Current geophysical methods (e.g. 3D reflection seismics) offer only a limited insight in hydraulic permeability, which the TRACE project aims to expand by applying a multi tracer anal...

We report on the realization of Atom Trap Trace Analysis for 39Ar and its first application to dating of groundwater samples. The presented system achieves an atmospheric 39Ar count rate as high as 3.58 ± 0.10 atoms/h allowing for the determination of the 39Ar concentration in less than a day. We demonstrate that the measured count rates are propor...

(1) Identifikation von tiefgreifend permeablen Aufstiegsbereichen unabhängig von seismischen Daten (2) Risikominimierung bei der Fündigkeit in der Explorationsbohrungsphase (3) Sinnvolle Ergänzung der Exploration zur Eingrenzung einer 3D-Seismik (4) Potentielle Kostenreduktion durch fokussierte Eingrenzung kostenintensiver seismischer Kampagnen

In Germany electricity and heat production from hydrogeothermal energy use is restricted to the northern German Basin, the Upper Rhine Graben (URG) and the Molasse Basin. Cost-effective methods are desirable in hydrogeothermal exploration in optimizing locations for utilizing renewable geothermal energy. Active segments of faults introduce hydrauli...

A strontium isotope study combined with analyses of elemental strontium, chlorine and other trace elements is used to characterize near surface groundwater in a region east to the NNE striking western marginal fault of the northern Upper Rhine Graben between the River Rhine and Groß-Gerau. Groundwater samples (1 l) were filtered on site (0.45 µm) a...

Sr-Isotopie in Grundwässern des Oberrheingrabens (Raum Freiburg und Groß Gerau)

Noble gas isotope composition in thermal groundwater provides information about crust-mantle interactions, in form of geotectonic activity, volcanism and advective heat transfer. The knowledge of the geothermal state of the crust is useful for the indication of thermal energy resources, which are of significant environmental and economic importance...

Methods of age determination belong to the fundamental toolkit of modern Earth and environmental sciences, as well as archeology. Radiometric dating, based on the well-known radioactive decay of certain isotopes, is the gold standard among the dating methods, with radiocarbon (14C) as the most famous example. However, many more radioisotopes are ne...

This work presents a low cost strategy characterizing deep hydrogeochemical reservoirs using a combination of methods from hydrogeochemistry and isotope hydrology in hot springs and near surface groundwater. Data from the first sampling campaign in the northern Upper Rhine Graben, close to Groß-Gerau, Germany, shows promising results, indicating...

The chemically inert behaviour of noble gases, their well-known solubility in water and the long-term constancy of atmospheric noble gas mixing ratios make them a unique tool for paleoclimate studies of groundwater. This concept has recently been extended to fluid inclusions in speleothems. Here we use noble gas concentrations of fluid inclusions c...

In order to derive meaningful noble gas temperatures (NGTs) from speleothem fluid inclusions, precise and accurate measurements of noble gas concentrations on very small water samples are necessary. To optimise these measurements and their reliability, an investigation of the reproducibility and accuracy of the analytical procedure is essential. Wa...

The assessment of geothermal potential for deep geothermal energy production currently relies on expensive 3D reflexion seismic methods to identify adequate fault zones and geometry of the geothermal aquifer. However, this analysis does not allow the estimation of hydraulic permeability of active faults nor provides a characterisation of the chemic...

The mountainous Odenwald region in the federal state of Hesse/Germany is one of the main recharge areas for groundwater of the surrounding depressions, where substantial extraction for public water supply takes place. We investigated the groundwater to study residence times and mixing ratios of groundwater of different ages, define regions of groun...