Increased Water Loss Research Articles

Enhanced oxidative stability and quality of chilled mirror carp fillet using an antioxidant film of chitosan/clove essential oil nanoemulsion

This study evaluates the effects of chitosan/clove essential oil nanoemulsion antioxidant films (CH-CEON) on the oxidative stability and quality of chilled mirror carp fillets. During storage, increased lipid and protein oxidation of all samples was observed, which resulted in a darker color, a softer texture, and increased water loss. Compared to the control, the oxidation and quality deterioration were inhibited in other samples, with the best effect was observed in those treated with CH-CEON. The peroxide value, thiobarbituric acid reactive substances (TBARS), total viable count, pH, total volatile basic nitrogen (TVB-N), b*, centrifugal, and cooking loss of samples treated with CH-CEON were 20.8%, 37.4%, 20.6%, 4.5%, 58.8%, 13.5%, 23.4%, and 11.1% lower than the control at 12 days, respectively. Conversely, the active and total sulfhydryl content, L*, a*, and whiteness (W) increased by 64.4%, 31.9%, 13.4%, 186%, and 15.3%, respectively. The texture of the treated samples was improved, and the shelf life was extended by 5 days. These changes were attributed to the slow release of phenolics in the films, which inhibited oxidation and quality deterioration of fish by scavenging free radicals. Moreover, the nanoemulsion increased the contact between clove essential oil (CEO) and samples, adsorbing free radicals more efficiently. This highlights the significant potential of CH-CEON for application in fish preservation.

Physicochemical and Color Changes During Fruit Ripening in Pepper Species (C. annuum L., C. baccatum L., and C. chinense Jacq.) Exposed to Salt Stress

This study examines the impact of salt stress on the physicochemical and color characteristics of three pepper species (Capsicum annuum L., Capsicum baccatum L., and Capsicum chinense Jacq.) at different ripening periods. Peppers were exposed to 0 mM, 50 mM, and 100 mM NaCl during the green, breaking, and red ripening periods. The results showed that salt stress significantly influenced moisture content, total ash, pH, titratable acidity, water activity, and color parameters. C. chinense had the highest moisture content and water activity, while C. annuum demonstrated a higher total ash content and pigment density (ASTA value). As fruits ripened, moisture content decreased, and total ash content increased. Salt stress caused reductions in water activity, pH, and titratable acidity, with high salt concentrations leading to increased water loss and a decline in fruit quality. Furthermore, salt stress reduced color parameters and ASTA values, indicating suppressed carotenoid pigment synthesis. The study highlights the importance of developing salt-tolerant pepper varieties, as salt stress negatively impacts the physiological and biochemical quality of peppers. These findings suggest that appropriate agronomic strategies and careful environmental monitoring are essential for sustainable pepper production, particularly in areas with saline soils. The results provide valuable insights into the mechanisms through which salt stress affects pepper fruit quality and suggest avenues for improving crop resilience.

Dehydrated Brewery Residue (DBR) can reduce the cost of rabbit production in Brazil, but affects performance, blood nutrients, and carcass characteristics

The study aimed to determine the chemical composition, apparent digestibility of dry matter, energy, and nutrients of Dehydrated Brewery Residue (DBR) for New Zealand White rabbits, as well as evaluate performance, biochemical and immunological blood parameters, carcass characteristics, and meat quality. Two experiments were carried out: digestibility and performance, both in a completely randomized design. In the digestibility experiment, 20 animals of mixed sexes were used, from 45 to 60 days of age, which consumed reference feed (RF) or test feed (TF - 70% RF + 30% DBR). In the performance experiment, 50 mixed-sex animals were used from 31 to 70 days of age. For digestibility, bromatological analyses were made of total dry matter (DM), crude protein (CP), crude fiber (CF), neutral detergent fiber (NDF), acid detergent fiber (ADF), ether extract (EE), mineral matter (MM), organic matter (OM), calcium (Ca), phosphorus (P), gross energy (GE), hemicellulose, cellulose and lignin from samples of feces, feed (RF and TF) and experimental feed (DBR). In terms of performance, the treatments were the basal feed (BF) + four TF, made up of increasing levels of DBR inclusion (10, 20, 30, and 40%). Overall, the apparent digestibility coefficient (ADC) of DM was 64.68 ±7.91%, while the ADC of GE and CP were 67.39 ±7.79% and 80.64 ±8.99%, respectively, resulting in digestible energy and digestible protein contents of 3,081 ±356 kcal/kg and 17.97 ±2.00%. There was a linear reduction (P<0.05) in the final weight, daily weight gain, and daily feed intake, but there was a linear reduction in production costs (P<0.05) for both the 31- to 50-day phase and the 31- to 70-day phase. Circulating levels of calcium (P=0.013) and phosphorus (P=0.019) responded in a linear decreasing pattern to the experimental feeds. The same response was observed for slaughter weight, hot and cold carcass weight, yield of skin, head, commercial cuts, and relative weight of edible organs, as well as meat quality, in which the loss of water on thawing (P=0.004) and shear force (P=0.005) indicated less juiciness and less tenderness in the meat. Levels of 10 to 40% DBR in feed for rabbits from 31 to 70 days of age mitigate production costs, but result in a worsening of performance and reduce circulating levels of calcium and phosphorus, reduce carcass weight, commercial cuts, and edible organs, as well as increasing water loss on thawing, and reducing meat tenderness.

Soil, water and p losses by water erosion in soil treated with pig slurry

Pig slurry (PS) can modify the soil fertility and influence the water erosion. The aim of this research was to evaluate the effect of PS doses on the content phosphorus (P) in the soil and on water (WL) and P losses due to water erosion, in a Alfisol in southern Brazil. The treatments, totaling 0, 250, 500, and 1000 m3 ha-1 of PS applied in oats (Avena strigosa), corn (Zea mays), turnip (Raphanus sativus L.) and soybean (Glycine max), and in oat residues. Simulated rainfall (65 mm h-1 and 75 minutes) was applied three times (test -T) on corn and four T on turnip, soybean, and residues, with a simulator rotating-boom. T1 occurred one day after the application of the PS and the interval between the other T ranged from 14 to 70 days. The P in the soil was determined before and after the survey. During runoff, runoff samples were collected to determine WL and P in the water. The PS did not influence the P in the soil. The P in runoff water was 78% higher in the D1000 treatment than in D0, while the difference in total P loss was 90%. Soil P at the end of the research increased at the beginning of the research, and the content in the soil at the end of the research decreased with increasing layer depth. P loss increased with increasing water loss, while P in water increased with increasing P in the soil.

Response of submerged macrophytes of different growth forms to multiple sediment remediation measures for hardened sediment.

Climate change and intensified human activities have disrupted the natural hydrological regime and rhythm of river-connected lakes, extending the dry season, increasing water loss, and exposing previously submerged lake floors. This exposure has led to significant sediment hardening, which directly impacts submerged macrophytes. However, strategies to mitigate the negative effects of hardened sediments and promote the growth and development of submerged macrophytes remain largely unexplored. In this study, we selected typical hardened sediment from Dongting Lake to investigate the response of different growth forms of submerged macrophytes to multiple sediment remediation measures (loosening and litter addition) using a mesocosm experiment. The results indicated that loosening alone uniformly benefited all submerged macrophytes by increasing total biomass, relative growth rate (RGR), and the root/shoot ratio. Additionally, loosening altered the root traits of submerged macrophytes, promoting maximum root length (MRL) while reducing average root diameter (ARD). Moreover, different submerged macrophytes exhibited species-specific responses to the combination of loosening and litter addition. Notably, the combination of loosening and adding Miscanthus lutarioriparius litter had an antagonistic effect on the growth of Potamogeton wrightii and Myriophyllum spicatum. The response of functional traits of submerged macrophytes with similar growth forms to the same treatment was consistent. Our findings suggest that future sediment remediation efforts should consider matching specific treatments with the growth forms of submerged macrophytes to achieve optimal outcomes.

Freezing Promotes Postmortem Proteolysis in Beef by Accelerating the Activation of Endogenous Proteolytic Systems

This study investigated the effect of freezing and subsequent aging on beef quality, particularly focusing on the extent of postmortem proteolysis and tenderization. The longissimus lumborum muscle was collected from 8 steers 24 h postmortem, sliced into 8 2.5-cm-thick steaks, and randomly allocated into 4 groups. Treatment groups consisted of 1) aging at 4°C for 24 h; 2) aging for 168 h; 3) freezing at −20°C for 24 h followed by thawing/aging for 24 h; and 4) freezing for 24 h followed by thawing/aging for 168 h. In general, freezing decreased the color intensity of the steaks, whereas aging increased it (P < 0.05). Freezing also increased water loss, evidenced by greater drip loss and purge loss (P < 0.05). On the other hand, both freezing and aging improved beef proteolysis and tenderness (P < 0.05). This was associated with enhanced protease activity, indicated by greater calpain-1 autolysis and cathepsin B activity (P < 0.05). Additionally, freezing may have accelerated the activation of caspase-3, but our sampling timing did not permit verifying this possibility. This increase in the activity of proteases is likely caused by ice crystals disrupting cellular organelles, releasing factors that trigger their activation. In support of this, frozen steaks displayed an elevated level of free calcium and mitochondrial dysfunction (P < 0.05). Collectively, these findings suggest that freezing enhances postmortem proteolysis and tenderness in beef, likely by compromising key cellular organelles and subsequently accentuating the activity of several endogenous protease systems during aging.

Redox homeostasis and pH monitoring: a step forward to personalized medicine and dermatology

Skin is continually subjected to various environmental stressors, such as pollution, UV rays, and other oxidative damage factors. It is obligatory to ascertain the exact importance of redox status and ROS indicators, which may be assessed in diverse physiological fluids and tissues. Reactive oxygen species (ROS) can cause lipid peroxidation, which can compromise the integrity and functionality of skin cells by degrading membrane lipids. This may compromise the skin barrier, making the skin more prone to infections and environmental irritants, increasing water loss and dryness. Collagen in the dermis can covalently link to malondialdehyde (MDA), a byproduct of lipid peroxidation generated by oxidatively damaged skin lipids, to form MDA-collagen adducts. Several types of skin cancer are associated with a heightened vulnerability of DNA purine and pyrimidine bases to oxidative damage and altered DNA repair capacity (DRC). Damage from ROS may cause hyaluronate to become less viscous, which increases its susceptibility to degradation. Elastin hydrodynamic radius decreased the rate of self-assembly in response to ROS. Alterations in redox homeostasis can lead to various diseases and conditions, including vitiligo, actinic keratosis, psoriasis, contact dermatitis, systemic sclerosis, the onset of wrinkles, and skin aging. The most recent formulations' capacity to improve pH and Redox simultaneously can be attained by carefully selecting proposed antioxidant formulations. The combination of modern preparations is currently available and should be used in accordance with the suggested guidelines.

Functional analysis of multi-scale fractures within a single fracture cluster in multi-horizontal wells

Defining the fracture function at each scale in the reservoir helps to analyze and optimize the thermal recovery properties of the reservoir. This study aims to reveal the functionalities of fractures at different scales by simulating one single fracture cluster coupled in multi-scale fractures. The geometric layout and parameter characteristics of the main fractures, branch fractures, and micro-fracture domain are investigated to speculate on their functions and influence on heat extraction performance. The results display that the main fractures and micro-fracture domain serve as the predominant channel for fluid flow. The branch fractures exert control over the flow transition from the main fractures to the micro-fracture domain, thereby influencing the generation of preferential flow. Micro-fracture domain is the primary way of fluid filtration loss. When the thickness of micro-fracture domain increased from 0 m to 20 m, the production flow rate increased from 2 kg/s to 4.2 kg/s, and the water loss ratio increased from 1 % to 4.9 %. However, expanding the micro-fracture domain can significantly enhance production flow rate and heat recovery rate at the expense of increased water loss ratio. Notably, preferential-flow-induced thermal breakthrough will not occur prematurely in this process. The permeability of branch fractures exerts the most substantial influence on the overall heat extraction, owing to its greatest impact on reservoir lifespan. These findings would provide valuable insights for optimizing fracturing morphology in multi-horizontal wells.

Effects of preparticipating hypohydration oncardiac burden in recreational athletes.

The global temperature rise will have extensive consequences on our organ systems, but hypohydration caused by reduced water intake or increased water loss through sweating plays the most relevant role. Many studies have already demonstrated the association between hypohydration and impaired exercise performance, but data related to the cardiac burden of hypohydration are scarce. This study is a sub-investigation of our large, prospective, self-controlled trial on the effects of hypohydration on cardiopulmonary exercise capacity with previously published results. In the current sub-study, we analyzed the impact of hypohydration on cardiac burden in this cohort of fifty healthy, recreational athletes during cardiopulmonary exercise test.Therefore, each participant underwent cardiopulmonary exercise test with a standardized ramp protocol twice, once in hypohydrated state and once in euhydrated state as control, and the cardiac markers Troponin T, NT-pro-BNP and Chromogranin A were measured before and after the exercise test at each state. Mean age was 29.7 years and 34% of probands were female. Hypohydration led to a reduced body water, a significant decrease in oxygen uptake and lower levels of power output. Yet, Troponin T, NT-proBNP, Chromogranin A and lactate levels did not significantly differ between the two conditions.In this study cohort, decreased exercise capacity during hypohydration was more likely due to impaired cardiac output with diminished plasma volume rather than measurable cardiac stress from fluid deprivation. However, whether these data are generalizable to a diseased cohort is left unanswered and should be addressed in future randomized controlled trials.

Temperature influences desiccation resistance of bumble bees

Ongoing climate change has increased temperatures and the frequency of droughts in many parts of the world, potentially intensifying the desiccation risk for insects. Because resisting desiccation becomes more difficult at higher temperatures and lower humidity, avoiding water loss is a key challenge facing terrestrial insects. However, few studies have examined the interactive effects of temperature and environmental humidity on desiccation resistance in insects. Such studies on bees (Hymenoptera: Apoidea: Anthophila) are especially rare, despite their ecological and economic importance. Here, we crossed temperature (20, 25, and 30 °C) with humidity (<5, 50, >95 % RH) manipulations and measured time to mortality, water loss rates, and the water content at mortality of bumble bees (Bombus impatiens). We found that both higher temperature and lower humidity increased water loss rates, while warmer temperatures reduced survival time and lower humidity decreased water content at mortality. Additionally, we observed large intraspecific variation in water balance traits between colonies, and larger individuals survived longer and could tolerate more water loss before mortality. This study raises important questions about the mechanisms underpinning water loss in bumble bees and suggests that frequent access to nectar may be especially important for bumble bees’ water balance and survival in a warming and drying climate.

The Effect of Moisture Content on the Electrical Properties of Graphene Oxide/Cementitious Composites

Due to its ability to improve mechanical properties when incorporated into cement, graphene oxide (GO) has received extensive attention from scholars. Graphene oxide is also a filler that improves the self-sensing properties of cement composites (CCs). However, existing studies have not focused sufficient attention on the electric conductivity of cement composites filled with graphene oxide (GO/CCs) and their mechanisms, especially polarization. This study examines the effects of water content and temperature on the electrical conductivity of GO/CCs. GO/CC polarization phenomena are analyzed to reveal the conductive mechanism. The results show that water has a significant influence on the electrical conductivity of GO/CCs. With increasing water loss, the electrical resistivity of GO/CCs increases by four orders of magnitude. For the same water content, a 0.1% GO concentration significantly decreases the resistivity of GO/CCs. Temperature can significantly enhance the current intensity of GO/CCs; furthermore, there is a quadratic relationship between current intensity and temperature. The conductive mechanism of GO/CCs is attributed to the interaction between ionic conductivity and electronic conductivity.

SHOOT GRAVITROPISM 5 mediates the stomatal response to darkness in Arabidopsis.

Stomatal regulation, a multifaceted mechanism enabling plants to adapt to diverse environmental conditions and optimize photosynthesis for survival and growth, is considered crucial in drought stress tolerance research. To further enhance our understanding of stomatal regulation, we investigated the novel transcription factors involved in this process. Our findings reveal that SHOOT GRAVITROPISM 5 (SGR5) is involved in the stomatal response to darkness in Arabidopsis. Water loss measurements showed that SGR5-overexpressing plants retained more water, whereas SGR5-knockout lines exhibited increased water loss compared with the control. Unexpectedly, our analyses indicated that SGR5 was not associated with the abscisic acid signaling pathway, in contrast to its homologous transcription factor, INDETERMINATE DOMAIN 14. Instead, SGR5-knockout lines exhibited weakened stomatal closure responses upon transition to darkness. Collectively, our results highlight the regulatory role of SGR5 in mediating stomatal movement in response to darkness.

GhAGL16 (AGAMOUS-LIKE16) Negatively Regulates Tolerance to Water Deficit in Transgenic Arabidopsis and Cotton.

Cotton is one of the most economically important crops in the world, and drought is a key abiotic factor that can significantly reduce cotton yield. MADS-box transcription factors play essential roles in various aspects of plant growth and development as well as responses to biotic and abiotic stress. However, the use of MADS-box transcription factors to regulate water stress responses has not been fully explored in cotton. Here, we showed that GhAGL16 acts as a negative regulator of water deficit in cotton, at least in part by regulating ABA signaling. GhAGL16-overexpressing (GhAGL16-OE) transgenic Arabidopsis had lower survival rates and relative water contents (RWCs) under water stress. Isolated leaves of GhAGL16-OE Arabidopsis had increased water loss rates, likely attributable to their increased stomatal density. GhAGL16-OE Arabidopsis also showed reduced primary root lengths in response to mannitol treatment and decreased sensitivity of seed germination to ABA treatment. By contrast, silencing GhAGL16 in cotton enhanced tolerance to water deficit by increasing proline (Pro) content, increasing superoxide dismutase (SOD) and peroxidase (POD) activities, and reducing malondialdehyde (MDA) and hydrogen peroxide (H2O2) contents under water stress. Subcellular localization and transcriptional activation assays confirmed that GhAGL16 is a nuclear protein that lacks transcriptional self-activation activity. The expression of ABA biosynthesis-related genes (GhNCED3/7/14), a catabolism-related gene (GhCYP707A), and a gene related to the ABA signaling pathway (GhABF4) was altered in GhAGL16-silenced plants. Taken together, our data demonstrate that GhAGL16 plays an important role in cotton resistance to water stress.

A genome-wide association study identifies genes associated with cuticular wax metabolism in maize.

The plant cuticle is essential in plant defense against biotic and abiotic stresses. To systematically elucidate the genetic architecture of maize (Zea mays L.) cuticular wax metabolism, 2 cuticular wax-related traits, the chlorophyll extraction rate (CER) and water loss rate (WLR) of 389 maize inbred lines, were investigated and a genome-wide association study (GWAS) was performed using 1.25 million single nucleotide polymorphisms (SNPs). In total, 57 nonredundant quantitative trait loci (QTL) explaining 5.57% to 15.07% of the phenotypic variation for each QTL were identified. These QTLs contained 183 genes, among which 21 strong candidates were identified based on functional annotations and previous publications. Remarkably, 3 candidate genes that express differentially during cuticle development encode β-ketoacyl-CoA synthase (KCS). While ZmKCS19 was known to be involved in cuticle wax metabolism, ZmKCS12 and ZmKCS3 functions were not reported. The association between ZmKCS12 and WLR was confirmed by resequencing 106 inbred lines, and the variation of WLR was significant between different haplotypes of ZmKCS12. In this study, the loss-of-function mutant of ZmKCS12 exhibited wrinkled leaf morphology, altered wax crystal morphology, and decreased C32 wax monomer levels, causing an increased WLR and sensitivity to drought. These results confirm that ZmKCS12 plays a vital role in maize C32 wax monomer synthesis and is critical for drought tolerance. In sum, through GWAS of 2 cuticular wax-associated traits, this study reveals comprehensively the genetic architecture in maize cuticular wax metabolism and provides a valuable reference for the genetic improvement of stress tolerance in maize.

Vacuum-steam pulsed blanching: An emerging method to enhance texture softening, drying behavior and physicochemical properties of Cornus officinalis.

Vacuum steam pulsed blanching (VSPB) was employed as a novel blanching technology on Cornus officinalis to soften the tissue for subsequent coring and dehydration. The current work aims to explore its effect on mass transfer behavior, PPO inactivation, drying characteristics, physicochemical properties, antioxidant capacity, and microstructure of C. officinalis. Results showed that VSPB increased water loss, decreased solid gain, and increased weight reduction with increased blanching cycles. Besides, VSPB significantly changed physical properties and extensively reduced drying time which was attributed to the cell wall components dissolving and cell turgor pressure decreasing, also verified by observing microstructure alteration. PPO was completely denatured after blanching in 6 cycles, but phenolic compounds were still diffused or degraded. Notably, the content of flavonoids and antioxidant capacity significantly increased compared to fresh samples probably due to increased extractability caused by the disrupting cell structure. Besides, the carotenoids and ascorbic acid could be well preserved.

Small Papillae Regulated by SPD25 are Critical for Balancing Photosynthetic CO2 Assimilation and Water Loss in Rice

BackgroundThe leaf epidermis plays an important role in the transmission of light and the regulation of water and gas exchange, which influences the photosynthesis of mesophyll cells. Small papillae (SP) are one of the important structural elements of the leaf epidermis. The mechanism of the effect that small papillae have on rice leaf photosynthetic performance remains unclear.ResultsIn this study, a small papilla deficient 25 (spd25) mutant was isolated from japonica rice Longjin1. Small papillae were absent on the adaxial and abaxial leaf surfaces of the spd25 mutant and the silicon and cuticular wax content in the spd25 mutant leaves decreased. Map-based cloning and functional analysis revealed that SPD25, encoding a guanine nucleotide exchange factor for Rop, is a novel allele of OsRopGEF10. The spd25 mutant showed an increased water loss rate and reduced relative water content. The lower stomatal conductance in the spd25 mutant prevented water loss but decreased the intercellular CO2 concentration and net assimilation rate. The fluorescence parameters showed that the inhibited CO2 assimilation reaction feedback regulated the photochemical electron-transfer reaction, but the performance of Photosystem II was stable. Further analysis indicated that the excess light energy absorbed by the spd25 mutant was dissipated in the form of non-photochemical quenching to avoid photodamage through the optical properties of small papillae.ConclusionsSPD25 regulates the development of small papillae on the surface of rice leaves, which play an important role in balancing photosynthetic gas exchange and water loss. This study deepens our understanding of the physiological mechanisms by which small papillae affect photosynthetic performance.

SlCNR regulates postharvest water loss and wax accumulation in tomato fruit and directly represses the transcription of very-long-chain (VLC) alkane biosynthesis-related genes SlCER1-2 and SlCER6

Cuticular waxes play a crucial role in the control of quality and storability of fruit and many transcription factors (TFs) contribute to fruit wax accumulation and affect the postharvest water loss. The tomato SBP-box protein Colorless Non-Ripening (SlCNR) is commonly investigated as a TF regulating fruit ripening, and its regulation role in mediating postharvest water loss remains to be unknown. Here, we found that fruit of SlCNR knockout (KO) mutants (KO-SlCNR#16 and KO-SlCNR#23) generated by CRISPR/Cas9 editing system exhibited decreased postharvest water loss, while fruit of the SlCNR-overexpressing (OE-SlCNR#21 and OE-SlCNR#24) displayed increased water loss compared to the wild type (WT). The overall wax accumulation increased by 17–30% in fruit of SlCNR KO mutants and decreased by 26–42% in OE-SlCNR#21 and OE-SlCNR#24, accompanied by the change of major components of waxes, such as n-alkanes, triterpenoids, and primary alcohol. RNA-seq analysis showed that the expression of numerous genes involved in wax biosynthesis were up-regulated in fruit of KO-SlCNR#23, including SlCER1–2, which encodes one part of the VLC alkane formation complex, and SlCER6, which encodes a β-ketoacyl-coenzyme A synthase. Furthermore, we proved that SlCNR directly represses the transcription of wax biosynthetic genes SlCER1–2 and SlCER6 in vivo and in vitro, thereby negatively regulating wax accumulation. These findings expand our understanding in the genetic regulatory mechanisms governing ripe tomato fruit wax accumulation and present SlCNR as a novel target of wax accumulation and postharvest water loss.

Numerical and experimental study on intermittent spray cooling for plate-fin heat exchanger

This study develops numerical models to analyze evaporative cooling and air cooling in an intermittent spray cooling system. The impact of heat load and film thickness on evaporation time and heat transfer enhancement is investigated. Results indicate that a thinner initial liquid film improves cooling performance due to quicker heat transfer and evaporation. The average cooling performance ratio between evaporative cooling and air cooling is evaluated for different spray intervals. Experimental findings demonstrate a 20 % to 40 % enhancement in cooling performance across varying intervals, with a spraying surface ratio of 0.45. Comparison between numerical and experimental results shows that with a fixed spray period of 5 s and intervals ranging from 25 s to 45 s, the numerical inaccuracy remains within 15%. The calculation of heat transfer performance considers the effective water utilization percentage. Shorter intervals lead to increased water loss as subsequent spray droplets wash out the liquid water on the fins. For instance, with a spraying interval of 5 s, water loss reaches 32.2%, whereas it is 20% with a 25 s interval. These findings underscore the reliability of the numerical model in capturing system behavior and validating heat transfer enhancements under different operational conditions.

Patterns of Wetland Hydrologic Connectivity Across Coastal‐Plain Wetlandscapes

AbstractDepressional wetlands influence the functions of wetlandscapes by storing and releasing water, providing critical habitat, amplifying carbon and nutrient cycling, and influencing microclimate. Despite persistent subsurface connectivity, depressional wetlands are surrounded by uplands so only sporadically connect via surface pathways. However, the frequency, duration, and relative importance of surface connectivity in depressional wetlands remains poorly understood, limiting quantification of their landscape functions. Using multiple years of stage variation in 67 depressional wetlands across four contrasting wetlandscapes, we observed wetland spill elevation is exceeded 10%–40% of the time, with substantial variation within and between wetlandscapes. Moreover, surface connectivity increased water loss rates by 200%–350% on a depth basis and 350%–850% on a volumetric basis compared with subsurface water loss rates. This temporally disproportionate water export suggests that short‐lived surface connectivity is crucial for aggregate landscape export of water‐borne materials and numerous hydrologic and habitat services. Contrasting water loss rates above and below spill thresholds create homeostatic feedback that stabilizes water levels near the thresholds. We explored geomorphic, climatic, and vegetative influences on hydrologic connectivity, quantified as nighttime recession rates below the spill threshold for groundwater connectivity and percent time above thresholds for surface connectivity. Groundwater connectivity was consistently greater in deeper wetlands and wetlandscape identity was the primary factor explaining variation in surface and subsurface connectivity. Our results highlight the critical role of surface connectivity in coastal plain wetlands, illustrate the heterogeneity of those wetland functions within and across wetlandscapes, and provide hydrologic benchmarks for evaluating restoration of aggregate landscape functions.

Bridging structural and functional hydrological connectivity in dryland ecosystems

On dryland hillslopes, vegetation water availability is often subsidized by the redistribution of rainfall runoff from bare soil (sources) to vegetation patches (sinks). In regions where rainfall volumes are too low to support spatially continuous plant growth, such functional connectivity between bare soil and vegetated areas enables the establishment and persistence of dryland ecosystems. Increasing the connectivity within bare soil areas can intensify runoff and increase water losses from hillslopes, disrupting this redistribution and reducing the water available to sustain ecosystem function. Inferring functional connectivity (from bare to vegetated, or within bare areas) from structural landscape features is an attractive approach to enable rapid, scalable characterization of dryland ecosystem function from remote observations. Such inference, however, would rely on metrics of structural connectivity, which describe the contiguity of bare soil areas. Several studies have observed non-stationarity in the relations between functional and structural connectivity metrics as rainfall conditions vary. Consequently, the suitability of using structural connectivity to provide a reliable proxy for functional connectivity remains uncertain and motivates the work here.Relations between structural and functional connectivity metrics are established based on model simulations of rainfall-runoff on hillslopes with varying soil properties and vegetation patterns. These relations vary between two hydrologic limits – a ‘local’ (patch-scale) limit, in which functional connectivity is related to structural connectivity, and a ‘global’ (hillslope-scale) limit, in which functional connectivity is most related to the hillslope vegetation fraction regardless of the structural connectivity of bare soil areas. The transition between these limits within the simulations depends on rainfall intensity and duration, and soil permeability. While the local limit may strengthen positive feedbacks between vegetation and water availability, the implications of these limits for dryland functioning need further exploration, particularly considering the timescale separation between storm runoff production and vegetation growth.