In the preceding publication (1) mention has been made of the syntrophism existing between the mutant strains llA16 and 2OA19 of Escherichia COG. These mutants, requiring isoleucine and isoleucine plus valine respectively, were able to grow together on a minimal agar plate, free of amino acids, which would not support the growth of either mutant alone. The nature of this syntrophism forms the s...

[1] We explore the mechanisms whereby groundwater influences terrestrial water storage (TWS) in the Amazon using GRACE observations and two contrasting versions of the LEAF-Hydro-Flood hydrological model: one with and the other without an interactive groundwater. We find that, first, where the water table is shallow as in northwestern Amazonia and floodplains elsewhere, subsurface stores (vados...

Numerical simulations of water ̄ow and solute transport were used to investigate the e€ect of the recharge (rain/irrigation) at the soil surface on solute spreading and breakthrough in a realistic, three-dimensional, heterogeneous, vadose zone±groundwater ̄ow system. Results of the analyses suggest that smaller recharge at the soil surface increases the relative variability in the response of t...

This work extends the overlay and index methods for intrinsic groundwater vulnerability, that typically involve soil surface vadose zone, to (saturated) transport. The method is “hybrid” as it combines standard with a simplified process-based approach component. For latter, we make use of concept methodologies based on geomorphological analysis, employing tools are generally implemented in Geog...

Anaerobic ammonium oxidation (anammox) is recognized as an important process for nitrogen cycling, yet little is known about its role in the subsurface biosphere. In this study, we investigated the presence, abundance, and role of anammox bacteria in upland soil cores from Tianjin, China (20 m depth) and Basel, Switzerland (10 m depth), using isotope-tracing techniques, (q)PCR assays, and 16 S ...

Abstract. In water-stressed regions of the world, managed aquifer recharge (MAR), process intentionally recharging depleted aquifers, is an essential tool for combating groundwater depletion. Many groundwater-dependent regions, including Central Valley in California, USA, are underlain by thick unsaturated zones (ca. 10 to 40 m thick), nested within complex valley-fill deposits that can hinder ...

A lysimeter trench was established at the Gardermoen delta (50 km north of Oslo, Norway) to study the flow of water and transport and degradation of aromatic jet fuel components (toluene and o-xylene) in the undisturbed unsaturated zone. Site investigations with ground-penetrating radar revealed the presence of dipping sedimentary layers within the foreset unit. This study has shown that the fo...

When implementing remediation programs to mitigate diffuse-source contamination of aquifers, tools are required to anticipate if the measures are sufficient to meet groundwater quality objectives and, if so, in what time frame. Transfer function methods are an attractive approach, as they are easier to implement than numerical groundwater models. However, transfer function approaches as commonl...