Range Of Water Temperatures Research Articles

Fish Health Altered by Contaminants and Low Water Temperatures Compounded by Prolonged Regional Drought in the Lower Colorado River Basin, USA.

The goal of this study was to assess health of male Common Carp (carp, Cyprinus carpio) at four sites with a wide range in environmental organic contaminant (EOC) concentrations and water temperatures in Lake Mead National Recreation Area NV/AZ, US, and the potential influence of regional drought. Histological and reproductive biomarkers were measured in 17-30 carp at four sites and 130 EOCs in water per site were analyzed using passive samplers in 2010. Wide ranges among sites were noted in total EOC concentrations (>10Xs) and water temperature/degree days (10Xs). In 2007/08, total polychlorinated biphenyls (tPCBs) in fish whole bodies from Willow Beach (WB) in the free-flowing Colorado River below Hoover Dam were clearly higher than at the other sites. This was most likely due to longer exposures in colder water (12-14 °C) and fish there having the longest lifespan (up to 54 years) for carp reported in the Colorado River Basin. Calculated estrogenicity in water exceeded long-term, environmentally safe criteria of 0.1-0.4 ng/L by one to three orders of magnitude at all sites except the reference site. Low ecological screening values for four contaminants of emerging concern (CEC) in water were exceeded for one CEC in the reference site, two in WB and Las Vegas Bay and three in the most contaminated site LVW. Fish health biomarkers in WB carp had 25% lower liver glycogen, 10Xs higher testicular pigmented cell aggregates and higher sperm abnormalities than the reference site. Sperm from LVW fish also had significantly higher fragmentation of DNA, lower motility and testis had lower percent of spermatozoa, all of which can impair reproduction. Projections from a 3D water quality model performed for WB showed that EOC concentrations due to prolonged regional drought and reduced water levels could increase as high as 135%. Water temperatures by late 21st century are predicted to rise between 0.7 and 2.1 °C that could increase eutrophication, algal blooms, spread disease and decrease dissolved oxygen over 5%.

Body size- and temperature-related metabolic traits of juvenile chum salmon during northward migration

Due to rapid ocean warming at higher latitudes, northward habitat shifts of the dominant anadromous fish in the Northern Hemisphere, chum salmon ( Oncorhynchus keta), have recently been reported. Physiological development is considered to be a trigger for habitat shifts during early life. However, the possibility of physiological adaptations to future ocean warming is not fully understood, because data on the physiological traits of juveniles, such as metabolic rate and swimming performance, are limited. Using swim tunnel respirometers, we identified the metabolic traits of different-sized chum salmon juveniles originating from the Sanriku coastal river, Japan, which is far from the northern feeding grounds. The weight gain of >2 g steeply increased the prolonged swimming performance, and the metabolic cost of swimming against the southward current in the Sanriku coast decreased with weight gain under the sea water temperature range of 8–12 °C. These findings indicate weight gain and inhabiting areas with temperatures < 13 °C might provide potential benefits for northward migration. These results will be valuable when assessing the increased costs associated with changing ocean conditions.

The influence of water and air temperature on elite wheelchair triathlon performance

ABSTRACT Impaired thermoregulatory function is a clinical feature of many health conditions that affect triathletes using wheelchairs and consequently, individual athlete performances may fluctuate according to environmental temperature. We aimed to determine the effect of 1) water temperature on wheelchair triathlon swim time, and 2) air temperature on handcycle and wheelchair run (push) time. Published race records from 2017 to 2023 (n = 49events) were extracted from the World Triathlon website. Bayesian negative binomial regression was used to separately model the nonlinear relationships between water temperature and swim time, and air temperature and handcycle and push time. Age, sex, sport class, whether wetsuits were worn (swim model) and swim time (handcycle and push model) were included as fixed effects. Over the observed water temperature range of 15.7–30.5°C, male swim time (mm:ss) improved from 14:13 min (95% credible interval [CrI] = 12:27, 16:09) to 12:35 min (95% CrI = 11:00, 14:19). Female swim time improved from 15:33 min (95% CrI = 13:24, 17:55) to 12:46 min (95% CrI = 11:03, 14:38). It was unclear whether handcycle and push time slowed over the observed air temperature range of 14–33°C. Warmer water temperatures, up to 30.5°C, were associated with faster swim times. It was unclear whether combined handcycle and push time slowed with increases in air temperature, up to 33°C. The integration of information on athlete impairment type and severity with performance data is needed to better understand the extent to which individual athlete performances fluctuate across environmental conditions.

Development and experimental testing of an innovative nondestructive thermal sensor utilizing the thermal interrogation method for detecting leakage in water plastic pipes

Leak detection in water pipelines is still an important issue in real-world industrial systems. Thus, a new nondestructive thermal sensor design based on the thermal interrogation method has been developed to detect and estimate the real-time leaks in water plastic pipes without environmental interference. The proposed thermal interrogation method utilizes a combination of heat flux and temperature measurements on the upstream and downstream outside plastic pipe surfaces. These measurements are obtained by using heat flux sensors and thermocouples that are covered by thin-film polyimide electric heaters. The interrogation method approach delivers that at constant input heat flux, the difference in sensor temperature values is dependent on the leakage volume flow rates. The sensor was tested over a range of water leakage volume flow rate from 0.1 m3/h to 1.3 m3/h and a range of water temperature from 21 °C to 25 °C. The water leakage volume flow rates were correlated to the difference in temperature values between the upstream and downstream sensors. The measurement results reveal that this sensor can be used to detect and estimate the real-time water leakage volume flow rate with high accuracy and repeatability for plastic pipes.

Physicochemical and microbiological assessment of multi‐village drinking water source in diarrheal hotspot areas of north Shoa zone, Amhara region, Ethiopia

AbstractQuality water is essential to people's health and social and economic well‐being. Evaluation of the quality of the water sources provides benchmark data on quality status and insights into the development of further protective measures. A laboratory‐based cross‐sectional study design was conducted in the diarrheal hotspot area of the North Shewa zone. The contamination risks of water sources were assessed using the World Health Organization (WHO) sanitary inspection checklist. A grab water sample was collected from 138 multi‐village drinking water sources according to WHO guidelines. The collected sample was processed for physicochemical and microbiological analysis. Data were recorded and analyzed using SPSS version 25 software. The inspection survey indicated there was no proper handling of the water sources. The water temperature range was between 7 and 32°C, while the turbidity values ranged from 1.8 to 6 NTU. Electrical conductivity, pH, and total dissolved solutes were 100% within the acceptable limits of WHO and the Ethiopian Ministry of Health (EMoH) water quality guidelines. However, only (77/138, 55.79%) and (101/138, 73.29%) drinking water sources were within the acceptable range of temperature and turbidity, respectively. The mean bacteriological counts in multi‐village drinking water sources were a mean value of 72.14, 29.78, 21.09, and 15.64 for TMC, TCC, FC, and FSC, respectively. A total of (19/138, 13.8%) drinking water samples were positive for total coliform (Tc) and/or fecal coliforms (Fc). The remaining (119/138, 86.2%) water samples were bacteriologically potable. The physicochemical quality of the drinking water sources was consistent with WHO and national water quality standards, except that turbidity exceeded the acceptable range. The results also showed that some water sources were contaminated with fecal and total coliform, which was supported by an inspection survey in which most water sources were poorly protected. These research findings can serve as a valuable evidence base for informing policy decisions and guiding practical interventions aimed at ensuring access to safe drinking water in diarrheal hotspot areas.

Accelerometer-based swimming metabolism of smallmouth bass (Micropterus dolomieu).

Bioenergetics is informative for a range of fundamental and applied resource management questions, but findings are often constrained by a lack of ecological realism due to the challenges of remotely estimating key parameters such as metabolic rate. To enable field applications, we conducted a calibration study with smallmouth bass (Micropterus dolomieu, 0.7-2 kg) surgically implanted with accelerometer transmitters and exposed to a ramp-Ucrit swimming protocol in a swim tunnel respirometer across a range of water temperatures (6, 12, 18, and 24°C). There was an exponential increase in fish acceleration with swimming speed, and acceleration per speed was higher in smaller fish and female fish, and at colder temperatures. Mass-specific fish metabolic rate (MO2; mg O2 kg-1 h-1) increased with swimming speed, acceleration, and temperature, and decreased with fish mass, which when combined were strong predictors of MO2. Maximum metabolic rate (MMR) was estimated to peak at 22°C, but maximum sustained swimming speed (Ucrit) remained high at c. 90-100 m s-1 above 20°C, based on second-order polynomial functions. Aerobic scope (AS) estimates peaked at 20°C (>90% AS at 17-24°C; >50% AS at 11-28°C). Males exhibited marginally higher MMR, AS, and Ucrit than females at higher temperatures. Larger fish generally exhibited higher Ucrit, but smaller fish had a marginally broader performance range (AS, Ucrit) among temperatures, benefiting from higher MMR despite a steeper increase in resting metabolic rate with temperature. These findings enable field studies to estimate metabolic metrics of smallmouth bass in situ to characterize their ecological energetics and inform bioenergetics models.

Inter-individual variability in developmental traits in tadpoles of the Baja California chorus frog (Pseudacris hypochondriaca) in response to temperature

Phenotypic plasticity is the intraspecific expression of different phenotypes in response to environmental conditions. Inter-individual variability refers to the range of phenotypes produced between conspecifics within a population, and such variability is ubiquitously observed among animals. Investigating inter-individual variability can help develop a more comprehensive understanding of how phenotypes respond to environmental change. The Baja California chorus frog ( Pseudacris hypochondriaca) is found in a variety of ecosystems that differ in temperature and elevation throughout its latitudinal range (∼1400 km) from Santa Barbara County, California to Baja California, Mexico. The chorus frog experiences a variable thermal environment across its life history and males initiate mating calls at a wide range of water temperatures, between 4 and 20°C. Embryos develop successfully between 8 and 29°C, and tadpoles between 0 and 33°C. We have previously observed inter-individual variability in developmental traits, such as development rate and metabolic rate, and therefore aimed to investigate this variability within and between temperatures more closely. Chorus frog eggs were collected from a wetland on the CSUSM campus the day after being laid, and incubated at 15°C or 22°C. Once tadpoles reached the target stage (Gosner Stage 33; hind limb toe differentiation), oxygen consumption rate (Vȯ2) was measured using intermittent respirometry, and body length, wet mass and dry gut-free masses were measured. We also investigated the effect of temperature on swimming speed and time to exhaustion. Average time to stage, wet mass, dry gut-free mass and body length all decreased at 22°C, while mass-specific Vȯ2 increased. We observed decreased variability at 22°C compared to 15°C in time to reach stage (days from first to last tadpole to reach stage: 30.2 ± 2.7 days at 15°C, 15.4 ± 1.1 at 22°C), wet mass (wet mass range: 148.8 ± 14.2 mg at 15°C, 105.1 ± 11.3 mg at 22°C), and dry gut-free mass (dry gut-free mass range: 14.2 ± 1.2 mg at 15°C, 7.3 ± 0.7 mg at 22°C). Variability in body length did not differ between temperatures (total length range: 7.7 ± 0.4 mm at 15°C, 6.4 ± 0.5 mm at 22°C). In contrast to other traits, variability in mass-specific Vȯ2 increased at 22°C compared to 15°C (mass-specific Vȯ2 range: 0.61 ± 0.07 μl h−1 mg−1 at 15°C, 1.63 ± 0.21 μl h−1 mg−1 at 22°C). Overall, there is a correlation between the average effect of temperature and the inter-individual variability of phenotypic traits, with higher temperature resulting in less inter-individual variability in development rate and morphological characteristics, which are faster and smaller at higher temperature, while variability in mass-specific Vȯ2 increased with temperature, reflecting the increase in average Vȯ2 that occurs at higher temperature. CS supported by a Beckman Scholarship. CAM supported by a CSUSM Research, Scholarship and Creative Activities Grant. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Effect of thermomechanical aging on force system of orthodontic aligners made of different thermoformed materials : An in vitro study.

The aim was to investigate the effect of aging by thermocycling and mechanical loading on forces and moments generated by orthodontic clear aligners made from different thermoplastic materials. Atotal of 25thermoformed aligners made from 5different materials, i.e., Essix ACE® and Essix® PLUS™ (Dentsply Sirona, Bensheim, Germany), Invisalign® (Align Technology, San Jose, CA, USA), Duran®+ (Iserlohn, Germany), Zendura™ (Fremont, CA, USA), underwent a14-day aging protocol involving mechanical loading (a0.2 mm vestibular malalignment of the upper left second premolar [tooth25]) and thermocycling in deionized water (temperature range 5-55 °C). The 3D forces/moments exerted on tooth25 of aresin model were measured at three time points: before aging (day0), after 2days and after 14days of aging. Before aging, extrusion-intrusion forces were 0.6-3.0 N, orovestibular forces were 1.7-2.3 N, and moments as mesiodistal rotation were 0.3-42.1 Nmm. In all directions, multilayer Invisalign® exhibited the lowest force/moment magnitudes. After aging, all materials showed asignificant force/moment decay within the first 2days, except Invisalign® for orovestibular and vertical translation. However, following thermomechanical aging, Duran®+ and Zendura™ aligners had equivalent or even higher vestibular forces (direction of mechanical load). Thermomechanical aging significantly reduced forces and moments during the first 48 h. Multilayer aligner materials exhibit lower initial forces and moments than single-layer ones, and were less influenced by aging. Material hardening was observed after subjecting some of the aligner materials to mechanical loading. Thus, orthodontists should be aware of possible deterioration of orthodontic aligners over time. This work also sheds light on how material selection impacts the mechanical behavior of aligners and may provide valuable guidance regarding optimal timing for the aligner changing protocol.

Performance investigation on dual bed adsorption chiller integrated with a partially covered N-PVT collector

The theoretical performance investigation of the adsorption chiller system integrated with a partially covered N-PVT Collector is mathematically modeled and presented in the paper. The study employs a MATLAB-Simulink integrated interface, and the silica gel-water combination serves as the working pair. The average weather conditions of Shiv Nadar Institute of Eminence for the month of May are taken into account the study. The investigation shows that solar energy integrated with an adsorption cooling system could efficiently provide a cooling effect. The results suggested that, due to the direct integration of the PVT with the chiller system, the influence of cycle operation is significant at the minimum and maximum solar radiation times. An optimization research for the optimal number of collectors for silica gel regeneration revealed that using N = 5 collectors results in an outlet hot water temperature range of 110 0C. During operation, the maximum adsorption capacity of 0.21 kg of water/Kg desiccant is obtained, for providing an adequate cooling effect. The system achieved a specific cooling power of between 50 and 200 W/kg during the process, and a coefficient of performance between 0.15 and 0.23.

Mitigation of Mycotoxins in Food-Is It Possible?

Among microorganisms found in food, fungi stand out because they are adaptable and competitive in a large range of water activities, temperatures, pHs, humidities and substrate types. Besides sporulating, some species are toxigenic and produce toxic metabolites, mycotoxins, under adverse biotic and abiotic variables. Microorganisms are inactivated along the food chain, but mycotoxins have stable structures and remain in ready-to-eat food. The most prevalent mycotoxins in food, which are aflatoxins, fumonisins, ochratoxin A, patulin, tenuazonic acid, trichothecenes and zearalenone, have maximum tolerable limits (MTLs) defined as ppb and ppt by official organizations. The chronic and acute toxicities of mycotoxins and their stability are different in a chemical family. This critical review aims to discuss promising scientific research that successfully mitigated levels of mycotoxins and focus the results of our research group on this issue. It highlights the application of natural antifungal compounds, combinations of management, processing parameters and emergent technologies, and their role in reducing the levels and bioaccessibility. Despite good crop management and processing practices, total decontamination is almost impossible. Experimental evidence has shown that exposure to mycotoxins may be mitigated. However, multidisciplinary efforts need to be made to improve the applicability of successful techniques in the food supply chain to avoid mycotoxins' impact on global food insecurity.

Response Surface Optimization of Refractance Window Drying of Bitter Gourd Slices

This study was conducted to investigate the drying behavior of bitter gourd (Momordica charantia L.) slices in a refractance window dryer. Various drying parameters such as water temperature (70, 80 and 90 °C), sample thickness (1, 2 and 3 mm) and blanching time (2, 3 and 4 min) were investigated for their effects on drying time, dehydration ratio and color change. Out of the 18 experimental runs determined by the Box Behnken design, six central experiments, often referred to as center points, were specifically chosen to assess the reliability of results. Four different empirical models viz. Exponential, Henderson and Pabis, Page's, and Power law model were selected based on their established applicability in similar studies, and fitted to the kinetics data of refractance window drying of bitter gourd. Adequacy of fit was assessed using the coefficient of determination (R2 ) and standard error of estimate (SEE). Page’s model demonstrated an excellent fit to the experimental drying data with a higher R2 value of 0.996 and correspondingly lower SEE of 0.0217 compared to the other three models. Furthermore, the drying process parameters were optimized for the responses using the Response Surface Methodology (RSM). The best values (within the chosen range) of water temperature, sample thickness and blanching time were found to be 90 °C, 1 mm and 4 min, respectively at desirability value of 0.889. At above condition of water temperature (90 °C), sample thickness (1 mm) and blanching time (4 min), the predicted values for the drying time, dehydration ratio and color change were found to be 52.2 min, 9.7 and 55.25, respectively. The findings of this study will be useful for refractance window drying of bitter gourd in particular and for high moisture foods in general.

Thinning and dynamics of the glacier terminus at the Pasterze Glacier (Austria), 2016–2021

As a result of global warming, glaciers worldwide recede and lose mass. Glacier ablation is influenced by surface characteristics, in particular the existence of debris cover. The evolution of glaciers may also be influenced by the existence of proglacial lakes, which are worldwide increasing in number and size. We examine the recent changes of the terminus of Pasterze Glacier by discussing the thinning and dynamics of the glacier terminus along with the changes of the glacial-proglacial transition zone between September 2016 and September 2021. By considering land cover in the interpretation, we find that glacier surface characteristics show different rates of elevation changes and surface movement. We mainly use orthophotos and digital elevation models (DEMs) resulting from airborne surveys of 12 different acquisition dates, but also draw on ablation stake measurements, lake water level data, water temperature data, as well as thermal infrared (TIR) imagery. While debris-covered ice lowered typically −5.0 m a−1 ± 4.6 m a−1 (mean ± standard deviation), debris-free ice was affected by ablation in the range of −7.0 m a−1 ± 2.7 m a−1, thus demonstrating that melt rates in similar elevations are related to surface characteristics. The elevation change rates were, in most cases, in a similar range throughout the observed periods of time. The horizontal displacement close to glacier-marginal crevasses amounted to up to ∼8 m a−1, but was mostly in the range of ∼1–4 m a−1. Considering both horizontal displacement and elevation changes, we find that clean and dirty ice surfaces show larger thickness losses and are moving faster compared to debris-covered glacier surfaces. Diurnal and seasonal fluctuations of lake water levels in the range of decimeters and lake water temperatures mostly clearly exceeding 0 °C are indicative of the potential influence of the proglacial lake on the glacier terminus. Given the decelerating and decaying behavior of the Pasterze Glacier in recent decades, we interpret the change rates of surface lowering and horizontal displacement 2016–2021 to be influenced by other factors such as the recently formed proglacial lake. This is also supported by direct ablation measurements that mostly show lesser ice melt differences compared to DEM-based surface elevation changes, suggesting that other factors such as thermally-induced melting contributed to an increased elevation difference.

Evaluation of the Suitability of Using Artificial Neural Networks in Assessing the Effectiveness of Greywater Heat Exchangers

The use of greywater heat exchangers (GHEs) is an effective way to reduce energy consumption for heating domestic water. However, the available characteristics of this type of device are often insufficient and consider only a few selected parameters of water and greywater, which results in the need to look for tools enabling the determination of the effectiveness of GHEs in various operating conditions with incomplete input data. The aim of this paper was to determine the usefulness of artificial neural networks (ANNs). For this purpose, comprehensive experimental tests were carried out on the effectiveness of the horizontal heat exchanger, taking into account a wide range of water and greywater flow rates and temperatures of these media, as well as the linear bottom slope of the unit, which allowed for the creation of a database of 32,175 results. Then, the feasibility of implementing the full research plan was assessed using ANNs. The analysis showed that the impact of the media temperatures on the heat exchanger effectiveness values obtained using ANNs is limited, which makes it possible to significantly reduce the number of necessary experiments. Adopting only three temperature values of at least one medium allowed the generation of ANN models with coefficient values R2 = 0.748–0.999 and RMSE = 0.077–1.872. In the case of the tested GHE, the slope and the flow rate of the mixed water are of key importance. However, even in the case of parameters of significant importance, it is possible to reduce the research plan without compromising the final results. Assuming five different values for each of the four input parameters (a total of 625 combinations) made it possible to generate an ANN model (R2 = 0.993 and RMSE = 0.311) with high generalization ability on the full research plan covering 32,175 cases. Therefore, the conducted analysis confirmed the usefulness of ANNs in assessing the effectiveness of GHEs in various operating conditions. The approach described in this paper is important for both environmental and economic reasons, as it allows for reducing the consumption of water and energy, which are necessary to carry out such scientific research.

Experiment for the performance of a thin membrane inclined automatic wicking dew-point evaporative cooling device based on simulation results

The traditional indirect evaporative coolers necessitate a continuous operation of water pumps to ensure the wetting of wet channel walls. However, excessive water spraying can lead to a thickened water film, negatively impacting heat transfer efficiency and generating an additional pressure drop. Identifying suitable water supply strategies and exploring materials for the wet channel that possess good moisture retention and evaporation characteristics has drawn research attention over the years.In this study, an automatic wicking dew-point evaporative cooling device, whose structure was determined by corresponding optimal performance simulation research, was designed and manufactured. The thin film exhibits a certain inclination angle between the dry and wet channels to form a triangular channel to enhance support and increase heat transfer area. Utilizing the automatic water absorption characteristics of the membrane for water supply instead of spraying, makes the water more uniform and heat exchange more efficient. A comprehensive study was conducted on the effects of different operating parameters (working-to-intake air ratio, intake air velocity, water temperature, intake air temperature, and intake air humidity) on the performance of the device. The results indicate that the cooler performs best in high-temperature, low-humidity environments. When the inlet temperature, humidity, and velocity are within the range of 25–45 °C, 20–80 %, and 0.5–2.5 m/s, respectively, with a water temperature of 22 °C and an air-to-water flow rate ratio of 0.5, the maximum temperature drop can reach 14.8 °C, and the cooling capacity per unit area ranges from 13 to 150 W/m2. The wet-bulb efficiency and dew-point efficiency increased from 52.4 % and 33.6 % to 110.6 % and 88.5 %, respectively. When the air velocity increases from 0.5 m/s to 2.5 m/s, the product air temperature increases by 3.1 °C, and the wet-bulb efficiency and dew-point efficiency decrease by 25.1 % and 17.5 %, respectively. However, the variation trends of unit area cooling capacity and energy efficiency ratio (EER) are opposite. The optimal operating conditions are proposed with an air volume ratio of 0.5 and a water temperature range of 22–26 °C. Finally, the temperatures of the product air and water were observed during long-term operation testing to evaluate the stability of the device.

Is the Pyrenean newt (<em>Calotriton asper</em>) a thermoconformer? Cloacal and water temperature in two different thermal periods in a Pre-Pyrenean stream population

In ectothermic animals, heat seems to be a determining factor because it influences many vital activities such as locomotion, the ability to escape, feeding, and reproduction, among others. In aquatic environments, physical characteristics of water prevent small ectotherms from thermoregulating and therefore it is expected that their body temperature remains similar to water temperature. Throughout its distribution and annual cycle, the Pyrenean newt (Calotriton asper) is exposed to a wide range of water temperatures that affect its biological and ecological traits like the standard metabolic rate, oxygen consumption, activity period and growth pattern. This study analyses the relationship between the cloacal and water temperatures in a Pre-Pyrenean population of C. asper in two periods with well differentiated water temperatures (July and September). The aims are to establish if there are differences between sexes in cloacal temperature, whether reproductive activity modifies cloacal temperature, and to analyse the degree of thermoconformity of the species. The results indicate that cloacal temperature depends on the water temperature, corroborating the idea that C. asper is mainly a thermoconformer, as it corresponds to an aquatic ectotherm. However, the cloacal temperature of newts was slightly higher than water temperature. In individuals in amplexus, cloacal temperature was significantly higher than in specimens that are not in this mating position, and in July, females showed much greater dispersion in cloacal temperature than males, which is probably related to spawning behaviour.

Expanded, compressed, or equal? Interactions between spawning window and stream thermal regime generate three responses in modeled juvenile emergence for Pacific salmon

Climate warming poses challenges to native fish, particularly at high latitudes. We used incubation models to explore how interactions between spawning timing and daily varying water temperature affected emergence timing for five species of Pacific salmon in 33 thermally diverse streams in south-central Alaska. Interactions between spawning timing and stream thermal regime led to three different emergence timing responses: (1) “expanded” by typically 2–3 times the duration of the spawning window for summer spawning salmon at streams with a large annual water temperature range; (2) “equal” in duration to the spawning window, regardless of spawning timing, at streams with upwelling groundwater; and (3) “compressed” for late-spawning salmon where water temperature was cooler at spawning than at emergence. Across all sites, a ±15-day range in spawning timing had influence similar to anomalously warm winters (+2 °C to +3 °C) on the emergence timing window. Differences among species, spawning timing, and thermal regimes suggest that a range of adaptations in spawning behavior will likely enable Pacific salmon populations to accommodate shifting thermal regimes during their early life history.

Early spring testing of environments quality in the Novik Bay (Russky Island, Peter the Great Bay, Japan Sea) in April, 2023

Oceanographic and ecological properties were measured in the Novik Bay of Russky Island (Japan Sea) in early spring (April) of 2023, the indicating groups of microorganisms were examined. Good ecological state of the bay waters was detected. Stable density stratification was already formed, with the water temperature range from 2.3oС at the bottom to 10.0oС on the sea surface and salinity from 33.6 to 31.1, respectively. Dissolved oxygen content was high in the bottom layer (9.6–10.8 mg/L). In the surface layer, the oxygen content was lower, as well as chlorophyll a concentration. Abundance of the colony-forming heterotrophic microorganisms was rather low, so the waters of the bay were characterized as oligosaprobic and pure that indicated accumulation of easily accessible organic matter (accumulation predominated over destruction), apparently due to development of production processes. Some exceptions with zero balance between the production and destruction were found in the Trud Inlet, in the inlet of Sports Club, and at Podnozhye village. Bacteria of the sanitary-indicative group were recorded in small quantities at two stations where they indicated biological and fecal pollution of the water. Microorganisms growing on media with crude oil were observed everywhere, although their number was not high, so the waters of the Novik Bay were identified as low-polluted, in general. However, high abundance of phenol-resistant microorganisms at most of the stations was a signal of significant pollution by phenols, that could have both natural and anthropogenic sources. Metal-resistant microorganisms were not abundant in the surface layer that showed the minimal level of technogenic pressure. Their dominant group was Ni-resistant heterotrophs associated with combustion of hydrocarbon fuel.

Integration of booster heat pumps in ultra-low temperature district heating network: Prototype demonstration and refrigerant charge investigation

Decentral booster heat pumps (BHPs) integrated in ultra-low temperature district heating (ULTDH) systems are deemed a sustainable solution for low-carbon building systems. The performance of BHPs is critical for the implementation of ULTDH systems. In this study, we experimentally investigate the effect of refrigerant charge on temperature, pressure, system coefficient of performance (COP), and heating capacity to evaluate the operability and sensitivity of ULTDH. A performance-guaranteed range of refrigerant charge is proposed to ensure the feasibility of the system. We also analyse the component-level exergy destruction and the system-level exergetic efficiency of a BHP prototype. The exergetic efficiencies range from 24.9 % to 33.4 % under operational conditions for ULTDH. The condenser and evaporator's exergy destruction is influenced by the temperature profiles on both sides, suggesting the potential to improve BHP performance by tailoring operating parameters. Additionally, the return water temperature significantly affects the system COP when the domestic hot water supply temperature is fixed. Within the allowable range of return water temperature, BHP operation with high evaporator outlet water temperature can improve the overall efficiency of the ULTDH system.

Evaluating Muskellunge catch‐and‐release mortality at elevated summer water temperature

AbstractObjectiveFisheries managers and anglers have expressed concerns regarding warmwater angling mortality, representing a need to evaluate mortality rates at various water temperatures and multiple latitudes. Up to 97% of Muskellunge Esox masquinongy caught by anglers are released, and previous research on catch and release (C&R) for Muskellunge has suggested relatively low mortality rates (0–5%). However, those studies were all conducted within the range of water temperatures that are thermally optimal for Muskellunge and generally at water temperatures less than 25°C. As many Muskellunge populations routinely experience temperatures greater than 25°C during the summer months our objective was to quantify warmwater (>25°C) C&R mortality rates in Muskellunge.MethodsWe collected 102 adult Muskellunge (>760 mm) and stocked them into and identify factors influencing mortality by using experimental ponds. Adult Muskellunge (n = 102) were stocked into eight earthen or plastic‐lined flow‐through ponds (0.06–0.71 ha) at densities less than 16 fish/ha. Muskellunge (n = 50) were angled by utilizing specialized Muskellunge fishing gear at water temperatures of 19.6–32.6°C, with 32 fish being caught at temperatures exceeding 25°C. After being angled, fish were closely monitored for 2 weeks to assess mortality; fish that remained uncaught during the experiment were used as controls (n = 53).ResultMortality was greater for angled fish (30.0%) than for control fish (11.3%). Differences in C&R mortality were compared across a range of temperature regimes using Firth logistic regression. Five‐day cumulative temperature and net time were positively related to the probability of mortality, but size and sex were unrelated to mortality. Increasing C&R mortality with temperature was mitigated somewhat by lower catch rates at higher temperatures. Mortalities per 100 angler‐hours were 0 at <25°C, 4.98 at 25.00–27.49°C, 2.48 at 27.5–30.0°C, and 1.17 at >30°C.ConclusionRecent field studies have identified the importance of thermal refuge in mitigating summer C&R mortality of Muskellunge. This study identified specific temperature conditions responsible for elevated mortality in the absence of refugia. Although increasing temperatures above 25°C led to increasing C&R mortality in our ponds, lower catchability seemingly provided some mitigation. The interactive effects of thermal refugia and catch rates with temperature warrant further investigations into population‐level effects at varying levels of exploitation.

Thermal effectiveness and NTU of horizontal plate drain water heat recovery unit - experimental study

The operating characteristics of plate heat exchanger in horizontal drain water heat recovery unit for domestic shower system were investigated in an experimental study. Based on test data the thermal effectiveness (ε) and number of heat transfer units (NTU) were calculated. The tests were carried out in simulated real-world conditions in three shower water flow rates (water consumption levels) for 4, 8 and 12 l/min, and two primary and secondary flows configurations (balanced and unbalanced), as a reflection of the three shower intensity standards and water temperature range of 30–50 °C covering the usual user-specific shower conditions. The least favorable test results (ε = 18.6% and NTU = 0.24) were obtained for the drain water temperature of 26.6 °C and cold water / drain flow rate at 12/12 l/min. The most beneficial results (ε = 50.0% and NTU = 0.99) were obtained for the sewage temperature of 50.8 °C and 4/12 l/min. It has been shown that the higher the flow on the drain water side and lower on the cold water side, the better the effectiveness. For a system with equal and low flows on both sides, the drain temperature change has a negligible effect on the effectiveness (4% growth with a drain temperature increase of 25.4 °C for 4/4 l/min). The paper presents developed easy-to-use charts of the variability of the effectiveness and NTU with the drain water temperature relates to a different set of primary and secondary flows in horizontal, plate, compact drain water heat recovery exchanger. The results of effectiveness obtained in the research were compared to the values presented in the literature for other drain water heat recovery units, both in vertical and horizontal applications.