This study employed geo-electrostratigraphic and hydrogeological information to model and assess subsurface structure and hydrogeological properties within a major coastal environment in Nigeria's Niger Delta region, offering a high-resolution approach to groundwater resource management. The selection of the study area was predicated on its critical residential, agricultural, and economic significance, as well as its susceptibility to hydrogeological challenges arising from rapid urbanization and industrial activities. Unlike previous studies that utilized these methods independently, this research combined different geoelectrical technologies to enhance the accuracy of subsurface characterization. The results delineated four distinct geo-layers characterized by specific resistivity values, thicknesses, and depths, providing crucial insights into groundwater infiltration, storage potential, and contamination risks. The first geo-layer (motley topsoil) had resistivity values ranging from 95.2 to 1463.7 Qm. The second layer (sandy clay) exhibited resistivity values ranging from 8.8 to 2485.1 Qm. The third layer, identified as fine sand, exhibited resistivity values ranging from 72.5 to 1332.7 Qm. The fourth layer comprised coarse sands and it exhibited a mean resistivity of 525.98 Qm, indicating a well-drained permeable formation that could serve as an additional aquifer unit. A key innovation of this study was the quantitative assessment of hydrogeological parameters, including anisotropic coefficient, transverse resistance, longitudinal conductance, and groundwater yield potential index. The anisotropic coefficient ranged from 1.0 to 1.78 (mean: 1.17), revealing minimal sediment invasion and confirming the dominance of arenaceous sediments in the Benin Formation. The groundwater yield potential index varied from 3.14 x 102 to 8.1465 x 104 Qm2, highlighting areas of significant aquifer potential. The longitudinal conductance analysis revealed that 69 % of the study area has low aquifer protectivity, underscoring the region's vulnerability to contamination. Another novel contribution was the evaluation of soil corrosivity, which has direct implications for infrastructure longevity. Results indicate that 86 % of the study area is non-corrosive, making it suitable for long-term pipeline installation, a factor rarely integrated into groundwater assessments. The study alsoadvances understanding of the Benin Formation by linking resistivity variations to arenaceous-argillitic intercalations, and this significantly influences groundwater movement and contaminant transport. By synthesizing resistivity models, hydrogeological parameters, and contamination risk assessments, this research provides a more holistic framework for sustainable groundwater management. Furthermore, this research offers a robust framework for similar hydrogeophysical assessments in other regions with comparable geological and hydrological settings. (c) 2025 Guangzhou Institute of Geochemistry, CAS. Published by Elsevier BV. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

In geosciences, soil-water interactions are defined by soil water potential, which provides a quantitative estimate of the soil water thermodynamic state. Due to the interactions between water and soil particles, soil water has different physical properties than free water; hence, analyzing soil water may require different methods and approaches. Typically, soil water potential is defined as the sum of three independent functions: gravitational, osmotic, and matric. However, there is a problem with this definition because the osmotic and matric potentials exhibit coupling effects. Moreover, due to its high values, the matric potential dominates the total potential, whereas the gravitational potential may appear negligible. However, gravity may lead to different flow mechanisms altering the soil's mechanical behavior. As a result, it may not be valid to calculate the total water potential as the algebraic sum of the different potentials. There are also mathematical challenges in the common use of water potential; as soil saturation decreases, water potential can reach thousands of kPa, which requires mathematical balancing in the equations by multiplying it by a variable with a value near zero. However, multiples of numbers of different magnitudes are problematic from a mathematical perspective, especially when applied to numerical analysis. This paper discusses the strengths and limitations of the definitions and mathematical formulations of this variable.

A pot-controlled watering approach was employed to reveal the effect of soil water stress on photosynthetic physiology of Paspalum notatum Flugge under special climatic conditions in arid-hot valley region. Four treatments were set up: control (CK), low stress (LS), moderate stress (MS), and high stress (HS). Physiological measurements were taken to assess indices such as absolute plant height, canopy area, leaf area, leaf water content, and leaf water potential. Additionally, photosynthetic parameters were measured, including net photosynthetic rate, intercellular CO2 concentration, stomatal conductance and chlorophyll fluorescence. The results indicate that under water stress, as the duration of stress increases, the growth of Paspalum notatum Flugge was inhibited, the water available in the body of Paspalum notatum Flugge gradually decreased. Photosynthesis was inhibited and PS II reaction center was disrupted to some extent. To improve water retention, Paspalum notatum Flugge initiated self-protective mechanisms, diminishing leaf water potential and enhancing ability to absorb water from the soil. In the meantime, Paspalum notatum Flugge adjusted to adversity by reducing the stomatal aperture to inhibit water loss, lowering Tr, and increasing WUE. The experiment showed that after rehydration, damaged photosynthetic apparatus of Paspalum notatum Flugge retained a certain self-recovery capability. This phenomenon suggests the reversible deactivation of the photosynthetic apparatus in response to water stress.

In an increasingly dry environment, it is crucial to understand how tree species use soil water and cope with drought. However, there is still a knowledge gap regarding the relationships between species-specific stomatal behaviour, spatial root distribution, and root water uptake (RWU) dynamics. Our study aimed to investigate above- and below-ground aspects of water use during soil drying periods in four temperate tree species that differ in stomatal behaviour: two isohydric tracheid-bearing conifers, Scots pine and Norway spruce, and two more anisohydric deciduous species, the diffuse-porous European beech, and the ring-porous Downy oak. From 2015 to 2020, soil-tree-atmosphere-continuum parameters were measured for each species in monospecific forests where trees had no access to groundwater. The hourly time series included data on air temperature, vapor pressure deficit, soil water potential, soil hydraulic conductivity, and RWU to a depth of 2 m. Analysis of drought responses included data on stem radius, leaf water potential, estimated osmotically active compounds, and drought damage. Our study reveals an inherent coordination between stomatal regulation, fine root distribution and water uptake. Compared to conifers, the more anisohydric water use of oak and beech was associated with less strict stomatal closure, greater investment in deep roots, four times higher maximum RWU, a shift of RWU to deeper soil layers as the topsoil dried, and a more pronounced soil drying below 1 m depth. Soil hydraulic conductivity started to limit RWU when values fell below 10-3 to 10-5 cm/d, depending on the soil. As drought progressed,oak and beech may also have benefited from their leaf osmoregulatory capacity, but at the cost of xylem embolism with around 50 % loss of hydraulic conductivity when soil water potential dropped below -1.25 MPa. Consideration of species -specific water use is crucial for forest management and vegetation modelling to improve forest resilience to drought.

Over the past decades, anthropogenic disturbance of geological structures has been significantly documented in Slovakia, mainly driven by the national economy's demand for mining resources. Among these resources, brown coal, primarily mined in the Upper Nitra coal basin in the Prievidza district (Slovakia), has been essential. Mining activities around town of Handlov & aacute;, and villages of Ko & scaron;, C & iacute;ge & lcaron; and Sebedra & zcaron;ie, particularly at the C & iacute;ge & lcaron; coal mine, have induced several geological defects. These defects, characterised by large cracks and local landslides, disrupt the hydrogeological conditions, significantly impacting the soil water regime stability of the forest ecosystems in these damaged areas. This study investigates the variability and dynamics of the soil water potential in a mining-affected site (Ra & ccaron;kov laz) compared to an intact reference area (& Ccaron;ertove chodn & iacute;ky) between 2020 and 2022. Our findings suggest that mining activities could have substantial implications for the soil water regime and, consequently, the ecological stability of forest ecosystems.

Heatwaves and soil droughts are increasing in frequency and intensity, leading many tree species to exceed their thermal thresholds, and driving wide-scale forest mortality. Therefore, investigating heat tolerance and canopy temperature regulation mechanisms is essential to understanding and predicting tree vulnerability to hot droughts. We measured the diurnal and seasonal variation in leaf water potential (Psi), gas exchange (photosynthesis A(net) and stomatal conductance g(s)), canopy temperature (T-can), and heat tolerance (leaf critical temperature T-crit and thermal safety margins TSM, i.e., the difference between maximum T-can and T-crit) in three oak species in forests along a latitudinal gradient (Quercus petraea in Switzerland, Quercus ilex in France, and Quercus coccifera in Spain) throughout the growing season. Gas exchange and Psi of all species were strongly reduced by increased air temperature (T-air) and soil drying, resulting in stomatal closure and inhibition of photosynthesis in Q. ilex and Q. coccifera when T-air surpassed 30 degrees C and soil moisture dropped below 14%. Across all seasons, T-can was mainly above T-air but increased strongly (up to 10 degrees C > T-air) when A(net) was null or negative. Although trees endured extreme T-air (up to 42 degrees C), positive TSM were maintained during the growing season due to high T-crit in all species (average T-crit of 54.7 degrees C) and possibly stomatal decoupling (i.e., A(net) 0). Indeed, Q. ilex and Q. coccifera trees maintained low but positive g(s) (despite null A(net)), decreasing Psi passed embolism thresholds. This may have prevented T-can from rising above T-crit during extreme heat. Overall, our work highlighted that the mechanisms behind heat tolerance and leaf temperature regulation in oak trees include a combination of high evaporative cooling, large heat tolerance limits, and stomatal decoupling. These processes must be considered to accurately predict plant damages, survival, and mortality during extreme heatwaves.

Key messageThe high-wood-density species displays greater water limitation tolerance, as it maintains leaf transpiration under drought conditions.AbstractThe relationship between environmental conditions and plant hydraulic safety is essential to understand species' strategies to minimize damage to their hydraulic structure yet maintain function. In the Brazilian semi-arid, the relationships between rainfall seasonality, hydraulic conductivity, wood density, stomatal conductance, and phenology in different species still needs to be clarified. To better understand these relationships, we selected two deciduous trees species with contrasting wood density: (1) Commiphora leptophloeos (Mart.) J.B. Gillett (low wood density) and (2) Cenostigma pyramidale (Tul.) E. Gagnon & G. P. Lewis (high wood density) from the Caatinga dry forest of northeast Brazil. We tracked monthly measurements of whole-tree hydraulic conductivity, leaf stomatal conductance, leaf transpiration rate, xylem water potential, and phenology. We found that the low-wood-density species had a higher whole-tree hydraulic conductivity and an early leaf flush and fall. In addition, lower leaf transpiration rate and higher water storage capacity maintained high xylem water potential and stomatal conductance values, especially in the rainy season. On the other hand, the high-wood-density species had a lower whole-tree hydraulic conductivity and higher leaf transpiration rate, even during the dry season. These results point to the divergent hydraulic strategies employed by each species, further suggesting opposing hydraulic safety pathways during drought.

center dot Stomatal closure under high VPDL (leaf to air vapour pressure deficit) is a primary means by which plants prevent large excursions in transpiration rate and leaf water potential (Psi(leaf)) that could lead to tissue damage. Yet, the drivers of this response remain controversial. Changes in Psi(leaf) appear to drive stomatal VPDL response, but many argue that dynamic changes in soil-to-leaf hydraulic conductance (Ks-l) make an important contribution to this response pathway, even in well-hydrated soils. center dot Here, we examined whether the regulation of whole plant stomatal conductance (g(c)) in response to typical changes in daytime VPDL is influenced by dynamic changes in Ks-l. We use well-watered plants of two species with contrasting ecological and physiological features: the herbaceous Arabidopsis thaliana (ecotype Columbia-0) and the dry forest conifer Callitris rhomboidea. center dot The dynamics of Ks-l and g(c) were continuously monitored by combining concurrent in situ measurements of Psi(leaf) using an open optical dendrometer and whole plant transpiration using a balance. Large changes in VPDL were imposed to induce stomatal closure and observe the impact on Ks-l. center dot In both species, g(c) was observed to decline substantially as VPDL increased, while Ks-l remained stable. Our finding suggests that stomatal regulation of transpiration is not contingent on a decrease in Ks-l. Static Ks-l provides a much simpler explanation for transpiration control in hydrated plants and enables simplified modelling and new methods for monitoring plant water use in the field.

The ecosystem and economy's reliance on clean water is influenced by various factors such as geology, topography, soil types, activities, and the presence of plants and animals. The Ghana Water Company is encountering difficulties in delivering water to consumers in the Ashanti Region due to the shortage of surface water resources, leading to water rationing in the area. Furthermore, poor waste disposal practices, illegal mining, use of fertilizers, and industrial activities have resulted in surface and groundwater source damage. Therefore, there is a need to implement a reliable, simple, and timely method to assess groundwater quality. This study aims to employ GIS and RS techniques to evaluate groundwater quality and potential in the Ashanti Region, Ghana. The Water Quality Index (WQI) was estimated using pH, Total Dissolve Solid (TDS), Chloride, Total Hardness (TH), Nitrate, Temperature, Turbidity, Iron, and Electrical Conductivity (EC). The study then used the WQI distribution to conduct a groundwater potential analysis to identify suitable areas for borehole placement. Digital thematic layers and maps were developed to expose the spatial distribution of water quality parameters, enabling the identification of groundwater pollution control and remedial measures. The study estimated the region's groundwater potential using an integrated GIS and Analytical Hierarchical Process (AHP) technique, grouping under excellent, good, fair, and poor potential. The WQI in the Ashanti Region ranged from 5.208 to 134.232, with 32.252% of the study area having an excellent WQI and 60.168% of the study area having a good WQI. Poor water quality covered 7.550% of the study area. The results showed that the GIS-based AHP approach accurately mapped the spatial distribution of WQI and Groundwater Potential Zones (GWPZ). This information is helpful to planners in water resource management in groundwater exploration and future planning. Policymakers and stakeholders must ensure that groundwater sources are protected from pollution.

Groundwater constitutes a vital resource for public water supply, and thus, it is imperative to recognize the areas of highest potential for increasing availability. The present study employs the MaxEnt model to discern the most favorable areas for locating high -yield wells in Caxias do Sul, Rio Grande do Sul, southern Brazil, where the Serra Geral Aquifer System, a fractured volcanic aquifer, emerges. This aquifer system is characterized by its heterogeneous, discontinuous, and highly anisotropic nature. A dataset comprising 83 wells with high flow rates (>= 10 m3/h) was selected from the municipal registry of deep tubular wells, along with 14 factors that influence groundwater occurrence (specific capacity, transmissivity, altitude, slope, horizontal curvature, vertical curvature, relief dis index, drainage density, distance to drainage, topographic wetness index, distance to lineament, lineament density, precipitation, and soil hydrological group). The model output was a Groundwater Potential Map, which stochastically expresses the probability of obtaining flow rates >= 10 m3/h. The map was validated through cross -validation, resulting in an average accuracy of 65.14%, and by the Receiver Operating Characteristic analysis, resulting in an Area Under the Curve value of 0.911, indicating satisfactory validation. While the MaxEnt model is widely used in ecology to model species distribution, its application in groundwater prediction remains limited, particularly in fractured aquifers associated with volcanic rocks. Apart from optimizing the use of groundwater resources, this study also enhances the understanding of natural phenomena in this type of aquifer.