Search

Introduction: As precipitation patterns are predicted to become increasingly erratic, the functional maintenance of warm-temperate forests constitutes a key challenge for forest managers. In this study, 2-year-old Quercus acutissima seedlings were selected to elucidate the mechanisms whereby they respond to soil water fluctuations and the drought hardening effects on plant carbohydrate dynamics. Methods: Seedlings were trained under different soil water conditions for 2 months: drought (D), well-watered (W), 1-month drought and then 1-month well-watered (D-W), and 1-month well-watered and then 1-month drought (WD). The functional traits involved in water- and carbon-use strategies were explored at the end of the hardening period. Compared with seedlings in group W, seedlings in groups D, D-W, and W-D had increased potential for carbon uptake (i.e., light saturated point, maximum ribulose-1,5-bisphosphate (RuBP) saturated rate, and electron transport rate) and water uptake (i.e., fine root–to–coarse root ratio) and downregulated growth and mitochondrial respiration to decrease carbon consumption. After water fluctuation hardening, we performed a successional dry-down experiment for 1 month to detect carbohydrate dynamics and explore the acclimation caused by prior hardening. Results and discussion: Our results revealed that there were more soluble sugars allocated in the leaves and more starch allocated in the stems and roots of seedlings hardened in the D, W-D, and D-W treatments than that of seedlings hardened in the W treatment. No significant changes in total non-structural carbohydrates were found. In addition, we found near-zero (seedlings trained by D and D-W treatments) or negative (seedlings trained by W-D treatment) growth of structural biomass at the end of the dry-down experiment, which was significantly lower than that of W-hardened seedlings. This suggests that there was a shift in allocation patterns between carbon storage and growth under recurrent soil drought, which can be strengthened by drought memory. We conclude that Q. acutissima seedlings adjusted water- and carbon-use strategies in response to water fluctuations, whereas stress memory can enhance their overall performance in reoccurring drought. Therefore, taking advantage of stress memory is a promising management strategy in forest nurseries, and drought-trained seedlings might be more suitable for afforestation practices in sites characterized by fluctuating soil water content, considering the ongoing global climatic changes. [ABSTRACT FROM AUTHOR]

We observed the water level and temperature in the lower stretch of the Hsin-an river in China for different times to show the characteristics of the water table and temperature in the riparian zone under the influence of discharged low-temperature water. The water table in the riparian zone showed a typical daily cycle change with a fluctuation range of 239.42-275.99 cm, according to the findings. With increasing distance from the river, the amplitudes of the water table fluctuation were reduced, and the phases were lagged. In the high-temperature period, riparian temperatures range from 20.4°C to 26.0°C, whereas in the low-temperature phase, temperatures range from 12.9°C to 19.2°C. The temperature distribution in the riparian zone was described in the vertical direction as "warmer on the surface and cooler at the bottom" during high-temperature periods and "cooler on the surface and warmer at the bottom" during low-temperature periods, with the temperature gradient gradually decreasing with depth. There was clear temperature zonation in the horizontal direction during the hightemperature phase but none during the low-temperature period. The study will serve as a benchmark for future hyporheic zone ecological impact assessments. [ABSTRACT FROM AUTHOR]

With recent advances in calculation methods, the external factors that affect slope stability, such as water content fluctuations and self-configuration, can be more easily assessed. In this study, a three-dimensional finite element strength reduction method was used to analyze the stability of three-dimensional slopes under fluctuating water conditions. Based on soil parameter variations in engineering practice, the calculation models were established using heterogeneous layers, including a cover layer with inferior properties. An analysis of seepage, deformation and slope stability was carried out with 27 different models, including three different slope gradients and nine different corner angles under five different hydraulic conditions. The failure mechanism has been shown to be closely related to the change in matric suction of unsaturated soils and the geometric slope configuration. Finally, the effect of geometry (surface shape, turning corner and slope gradient) and water (fluctuations) on slope stability are discussed in detail. Emphasis is given to comparing safety factors obtained considering or ignoring matric suction.

The presence of freshwater decapods may be considered dependent on the habitat and vegetation characteristics in floodplain rivers. Water level can influence the availability of macrophytes and the associated species composition of freshwater decapods. Changes in the sex ratios, abundances and body sizes of Macrobrachium borellii, Palaemon argentinus and Trichodactylus borellianus were investigated focusing on the type (floating, emergent) and the presence/absence of macrophytes in the Middle Paraná River floodplains. Organisms were sampled and analysed from river sites with floating, emergent vegetation and vegetation-free waters during different hydrological periods. The presence of macrophytes and some environmental variables during different hydrological and seasonal periods affected the variations in the species composition of decapods. M. borellii and T. borellianus tended to increase with the increase in floating vegetation in high waters, while P. argentinus was abundant in emergent vegetation and vegetation-free waters in low waters. Macrophytes provide food and shelter for freshwater decapods, influencing the species abundance according to the ecological response of each species. Variations in macrophytes composition due to water-level fluctuations modify the abundance of freshwater decapods, altering the species composition of decapod assemblages. Floodplain rivers are complex systems that act as macrofactors that regulate other factors that impact species composition. [ABSTRACT FROM AUTHOR]

Introduction: As precipitation patterns are predicted to become increasingly erratic, the functional maintenance of warm-temperate forests constitutes a key challenge for forest managers. In this study, 2-year-old Quercus acutissima seedlings were selected to elucidate the mechanisms whereby they respond to soil water fluctuations and the drought hardening effects on plant carbohydrate dynamics., Methods: Seedlings were trained under different soil water conditions for 2 months: drought (D), well-watered (W), 1-month drought and then 1-month well-watered (D-W), and 1-month well-watered and then 1-month drought (W-D). The functional traits involved in water- and carbon-use strategies were explored at the end of the hardening period. Compared with seedlings in group W, seedlings in groups D, D-W, and W-D had increased potential for carbon uptake (i.e., light saturated point, maximum ribulose-1,5-bisphosphate (RuBP) saturated rate, and electron transport rate) and water uptake (i.e., fine root-to-coarse root ratio) and downregulated growth and mitochondrial respiration to decrease carbon consumption. After water fluctuation hardening, we performed a successional dry-down experiment for 1 month to detect carbohydrate dynamics and explore the acclimation caused by prior hardening., Results and Discussion: Our results revealed that there were more soluble sugars allocated in the leaves and more starch allocated in the stems and roots of seedlings hardened in the D, W-D, and D-W treatments than that of seedlings hardened in the W treatment. No significant changes in total non-structural carbohydrates were found. In addition, we found near-zero (seedlings trained by D and D-W treatments) or negative (seedlings trained by W-D treatment) growth of structural biomass at the end of the dry-down experiment, which was significantly lower than that of W-hardened seedlings. This suggests that there was a shift in allocation patterns between carbon storage and growth under recurrent soil drought, which can be strengthened by drought memory. We conclude that Q. acutissima seedlings adjusted water- and carbon-use strategies in response to water fluctuations, whereas stress memory can enhance their overall performance in reoccurring drought. Therefore, taking advantage of stress memory is a promising management strategy in forest nurseries, and drought-trained seedlings might be more suitable for afforestation practices in sites characterized by fluctuating soil water content, considering the ongoing global climatic changes., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Li, Liu, Sun, Zhao, Liu, Wang, Gao, Fan, Du, Wang and Wang.)

Groundwater fluctuation is directly linked with the consumption and wastage of water sources during the pandemic interval. That is why water resource planners directly target water resource and sanitation systems in line with the sustainable development goals (SDGs) concept. In this study, District Multan is designated as a study area with 85 distinct station points data sets from four zones taken to pursue this massive investigation. The data sets are studied analytically and graphically to explore the relationships among critical variables like population, average water consumption, groundwater elevation, water table depth, total consumption, wastage of water during the pandemic days, etc. For in-depth analysis, the statistical approaches are employed on these massive data sets to reveal the trend among each dataset point to generate predictive models. The results revealed that groundwater reservoirs and levels are continuously declining on an annual basis in the meantime, the water consumption and extraction are increasing simultaneously. The consumption during pandemic days has been increased so much at the same time the wastage and total consumption of water is rising a lot in contrast to previous daily consumption and water demand. The coefficient of determination (R-square) values vary from 0.41 to 0.93 in this investigation. It will help the utilization of developed models and water-providing organizations to forecast groundwater instabilities for the future. Moreover, the situation in the study area is very alarming in terms of water stress conditions. This study will help the decision-making agencies to produce a policy following the SDGs concept to control water consumption and higher extraction. [Display omitted] • Water fluctuations is directly linked with the consumption and wastage of water resource. • Groundwater has emerged as a critical resource for both human well-being and the country's economic prosperity. • Groundwater must be considered when planning and implementing SDGs. • During the epidemic disease pandemic appearance is taken as a burden on water reservoirs because during this disease the demand, consumption & wastage of water rises enough. • Groundwater must be considered when planning and implementing SDGs by making such linkages more apparent and describing their strength and direction. [ABSTRACT FROM AUTHOR]

The article describes the responses of waterbirds to the changes in water levels and salinity in the Mar Chiquita in Argentina. Detailed are the lake conditions and the observed population numbers of various bird species as shown in tables for the periods 1973 to 1977 and 1990 to 2002. It is concluded that the 1974-1977 lake environment was the most favorable with its very high salinity but further studies are needed to determine why this condition attracts the waterbirds.

With recent advances in calculation methods, the external factors that affect slope stability, such as water content fluctuations and self-configuration, can be more easily assessed. In this study, a three-dimensional finite element strength reduction method was used to analyze the stability of three-dimensional slopes under fluctuating water conditions. Based on soil parameter variations in engineering practice, the calculation models were established using heterogeneous layers, including a cover layer with inferior properties. An analysis of seepage, deformation and slope stability was carried out with 27 different models, including three different slope gradients and nine different corner angles under five different hydraulic conditions. The failure mechanism has been shown to be closely related to the change in matric suction of unsaturated soils and the geometric slope configuration. Finally, the effect of geometry (surface shape, turning corner and slope gradient) and water (fluctuations) on slope stability are discussed in detail. Emphasis is given to comparing safety factors obtained considering or ignoring matric suction. [ABSTRACT FROM AUTHOR]