The lack of a complete understanding of the complex reciprocal interactions between hydrological processes and the structure and function of microbial communities limits our ability to improve the predictions of microbial metabolism in streams. We report here on how overlying water velocity and losing and gaining flux interact with bacterial community structure and its activity to control oxygen consumption in a sandy streambed under high nutrient levels. We used an experimental flume packed with natural sediment and measured the bacterial biomass distribution and oxygen profiles in the streambed and across bed forms. Local oxygen consumption rates were calculated with a 1‐D numerical model (GRADIENT). Bacterial abundance and production rates varied across the bed form within 1 order of magnitude, while their taxonomic classes were similar across bed forms despite variations in flow conditions and sediment disturbance events. However, bacterial production rates were not directly correlated with bacterial abundance. On the other hand, oxygen consumption rates ranged over 4 orders of magnitude across the bed forms and were highly correlated with the vertical exchange flux between the water and the streambed. The results strongly suggest that under high nutrient levels, the system is, in general, transport limited and that predicting oxygen consumption rates depends on local vertical exchange fluxes.

Geological repositories for radioactive waste disposal require evaluation of host rock suitability across multiple, often incommensurable, criteria under conditions of deep uncertainty. This paper develops a non-aggregative multi-criteria decision analysis (MCDA) framework that preserves criterion-level visibility, accommodates irreducible uncertainty through 'Variable' ratings, and defers value-laden weighting to decision-makers. Applied to carbonate formations—chalk, marl, limestone, and dolostone—the framework reveals that carbonates are not generically unsuitable for disposal. Soft carbonates offer favorable matrix-dominated hydrogeology but are thermally and mechanically constrained; hard carbonates offer excellent thermal and mechanical properties but face critical uncertainty on fracture and karst controls. Both subtypes suffer from knowledge gaps that compound uncertainty across all criteria. The framework supports concept-sensitive evaluation: soft carbonate with deep borehole disposal merits investigation for long-lived intermediate-level waste, while hard carbonate with mined repository concepts requires intensive site characterization. For nations lacking conventional host rock options, this work provides a structured, transparent basis for evaluating carbonate formations and identifies priority research needs.

Objective: Due to limited freshwater supplies, Israel increasingly depends on desalination to fulfill its drinking water requirements. However, this process reduces mineral levels such as magnesium (Mg²⁺), calcium (Ca²⁺), and fluoride (F⁻), which could pose health concerns. In this study, we analyze the mineral concentrations across various water sources nationwide. Materials and Methods: We analyzed a national database on drinking water quality for levels of Ca²⁺, Mg²⁺, and F⁻ from 2014 to 2024. District-level concentrations were calculated and compared with national means and across primary water sources. Water sources were classified as primarily DSW (DSW) or primarily groundwater-based according to their dominant composition. Results: Nationwide median concentrations were 52 mg/L for Ca²⁺, 12 mg/L for Mg²⁺, and 0.15 mg/L for F⁻. Ca²⁺ and Mg²⁺ showed marked regional variation, with significantly higher mean levels in the Northern District (Ca²⁺: 72 mg/L, p < 0.006; Mg²⁺: 34 mg/L, p < 0.001) and lowest levels in southern regions, particularly the Southern District (Ca²⁺: 39 mg/L, p < 0.001; Mg²⁺: 7 mg/L, p < 0.001) compared to the national average. Fluoride concentrations were generally low, with higher levels in northern regions (0.23 mg/L, p < 0.001) and lower levels in Tel Aviv (0.07 mg/L, p < 0.001) and Jerusalem (0.11 mg/L, p < 0.001). By predominant water source, Ca²⁺ and Mg²⁺ concentrations were lowest in DSW (Ca²⁺: 42 mg/L; Mg²⁺: 9 mg/L) and highest in groundwater supplies (Ca²⁺: 83 mg/L; Mg²⁺: 34 mg/L). Concentrations of F⁻ ranged from 0.12 mg/L in predominantly DSW to 0.23 mg/L in areas supplied primarily by groundwater. Conclusions: Ca²⁺ levels aligned with international reports, while Mg²⁺ levels, especially in desalination-reliant areas, remained consistently low. F⁻ concentrations stayed below both the recommended maximums and the optimal levels advised by the U.S. Public Health Service. As desalination efforts grow, concerns have been raised about the potential public health risks associated with low-mineral drinking water, particularly cardiovascular disease and bone disorders.