Elevated Summer Research Articles

PlFabG improves high-temperature resistance in herbaceous peony by increasing saturated fatty acids

The herbaceous peony (Paeonia lactiflora Pall.) is renowned for its striking flowers, which are highly valued in the cut flower industry. However, in the middle and lower reaches of the Yangtze River, the elevated summer temperatures negatively affect the plant's flowering capacity in the subsequent year. 3-oxoacyl-ACP reductase (FabG) is a component of the type II fatty acid synthesis (FAS II) system, where it plays a role in facilitating the production of saturated fatty acids. However, its role in conferring resistance to high-temperature stress remains unclear. In order to investigate the function of PlFabG in dealing with high-temperature stress, we isolated PlFabG from P. lactiflora. The gene contains an open reading frame (ORF) of 780 bp, which encodes 259 amino acids. Quantitative real-time PCR (qRT-PCR) analysis showed that the expression levels of PlFabG increased with prolonged exposure to high temperature. Additionally, plants overexpressing PlFabG maintained a relatively healthy phenotype under high-temperature stress, whereas plants with silencing PlFabG exhibited more severe leaf scorching and wilting under the same conditions. Various physiological indices indicated that PlFabG reduced reactive oxygen species (ROS) accumulation and enhanced the saturation of photosystem II. Most importantly, PlFabG helped P. lactiflora withstand high-temperature stress by increasing the proportion of saturated fatty acids, thereby maintaining cell membrane integrity. These findings elucidate the beneficial role of PlFabG in enhancing plant tolerance to high temperature and provide a strong theoretical support for the development of high-temperature tolerance in transgenic P. lactiflora.

Field evaluation of biostimulants on growth, flowering, yield, and quality of snap beans in subtropical environment

The cultivation of snap beans (Phaseolus vulgaris L.) in subtropical regions faces environmental challenges leading to potential declines in yield. This study explores the efficacy of biostimulants as a solution, specifically investigating spraying treatments with 6-benzylaminopurine (6-BA), chitosan (Ch), triacontanol (TRIA), and potassium silicate (KSi) on the snap bean cv. Paulista. Over two growing seasons with late sowing and elevated summer temperatures, the research assesses growth, flowering, yield, and quality. Notably, 5 ppm TRIA demonstrates the most significant impact on plant growth and leaf nutrient content. Treatments with 40 ppm 6-BA, 5 ppm TRIA, or 200 ppm KSi exhibit notable effects on inflorescence flower count and flowers per plant. These treatments prove most effective for crucial green pod yield measures, including the number and weight of marketable pods. Moreover, 40 ppm 6-BA or 5 ppm TRIA significantly enhances pod characteristics, such as length, diameter, and weight, consistently improving over both seasons. Particularly, 5 ppm TRIA outperforms in enhancing the chemical quality of pods throughout the study. Overall, the findings suggest that the application of 5 ppm TRIA offers the most favorable enhancements for the growth, flowering, productivity, and quality of snap bean plants in subtropical field conditions.

Metabolic rate of two invasive Ponto‐Caspian goby species and their native competitors in the context of global warming

Abstract In connection with the expansion of alien gobies in European waters, a question arises whether this process can be enhanced or inhibited by global warming. The gobies are of Ponto‐Caspian origin, where the climate is warmer than in invaded European areas. Therefore, they are likely to cope physiologically with climate warming better than native species. Our aim was to identify differences in metabolic traits under elevated summer temperature between the invasive gobies and their native counterparts. Using a laboratory respirometer, we compared the effect of elevated summer temperature (25 vs. 17°C) on the metabolic responses of fish in two species pairs consisting of an invasive goby versus its native counterpart from the same ecological guild: the invasive racer goby Babka gymnotrachelus versus native European bullhead Cottus gobio, and the invasive monkey goby Neogobius fluviatilis versus native gudgeon Gobio gobio. The paired species share functional traits, including morphological characteristics, despite belonging to different fish families. After 4 weeks of acclimation, standard metabolic rate (SMR), maximum metabolic rate (MMR) and aerobic scope (AS = MMR–SMR) of the fish were determined. We found that SMR increased under elevated temperature irrespective of species, yet it was always lower in the gobies than in natives. The MMR of the racer goby was lower than that of the bullhead across all temperatures, whereas no differences in MMR were found between the gudgeon and monkey goby. On the one hand, the elevated temperature did not affect the AS of the racer goby and bullhead. However, the AS of the racer goby was consistently lower than that of the bullhead across all temperatures. On the other, elevated temperature caused a decrease in AS in both the monkey goby and gudgeon. However, this temperature‐induced change in AS was higher in the gudgeon than in the monkey goby. In terms of AS, the invaders did not always outperform the natives at higher temperatures. However, the invaders had lower living costs by maintaining a lower SMR. These results suggest that invasion by gobies may be facilitated by global warming, which is likely to increase their occurrence and effect on local fish communities in freshwater temperate systems.

Variability in the summer movements, habitat use and thermal biology of two fish species in a temperate river

The ability of fish to cope with warm water temperatures in summer depends on factors including their thermal traits and the ability of individuals to access cool-water refugia. Knowledge is highly limited on the in situ responses of many fishes to elevated summer temperatures, including whether they express behavioural thermoregulation. The responses of two riverine species to summer water temperatures were tested here using the movement metrics, spatial habitat use and body temperatures of individual European barbel Barbus barbus (‘barbel’) and common bream Abramis brama (‘bream’) versus river temperatures. Acoustic biotelemetry was applied in the lower River Severn basin, western Britain, in summer 2021 (barbel) and 2022 (bream), where individuals could move across > 150 km of river, including a tributary of cooler water. Across all individuals, bream occupied 37 km of river length (mainstem only), with low inter-individual variability in their spatial habitat use, movements and body temperatures. In contrast, barbel occupied 62 km of river (main river/tributary), with relatively high inter-individual variability in spatial habitat use, movements and body temperatures, with higher variation in body temperatures as river temperatures increased (maximum mean daily temperature difference between individuals on the same day: 4.2 °C). Although warmer individuals generally moved more, their activity was greatest at relatively low temperatures and higher flows, and neither species revealed any evidence of behavioural thermoregulation during elevated temperatures. Enabling phenotypically diverse fish populations to express their natural behaviours and thermal preferences in summer water temperatures thus requires maintaining their free-ranging in thermally heterogenous habitats.

Seasonal impact of constructed wetlands on nitrogen and phosphorus in sediments of flood control lakes with pollution assessment.

The primary drivers of eutrophication in lakes following the reduction of external nutrient inputs are the release of N and P from sediments. Constructed wetlands play a pivotal role in ameliorating N, P, and other biogenic element levels. However, the presence of large vegetation in these wetlands also substantially contributes to nutrient accumulation in sediments, a phenomenon influenced by seasonal variations. In this study, a typical constructed wetland was selected as the research site. The research aimed to analyze the forms of N and P in sediments during both summer and winter. Simultaneously, a comprehensive pollution assessment and analysis were conducted within the study area. The findings indicate that elevated summer temperatures, together with the presence of wetland vegetation, promote the release of N through the nitrification process. Additionally, seasonal variations exert a significant impact on the distribution of P storage. Furthermore, the role of constructed wetlands in the absorption and release of N and P is primarily controlled by the influence of organic matter on nitrate-nitrogen, nitrite-nitrogen, and available phosphorus, and is also subject to seasonal fluctuations. In summary, under the comprehensive influence of constructed wetlands, vegetation types, and seasons, sediments within the lake generally exhibit a state of mild or moderate pollution. Therefore, targeted measures should be adopted to optimally adjust vegetation types, and human intervention is necessary, involving timely sediment harvesting during the summer to reduce N and P loads, and enhancing sediment adsorption and retention capacity for N and P during the winter.

Persistence of Holocene ice cap in northeast Svalbard aided by glacio-isostatic rebound

The deglaciation of the Svalbard-Barents Sea Ice Sheet was driven by relative sea-level rise, the incursion of North Atlantic waters around Spitsbergen, and increasing summer insolation. However, ice retreat was interrupted by asynchronous re-advances that occurred into high relative seas, during a period associated with warm regional waters and elevated summer temperatures. Better understanding of this complex style of deglaciation and the dynamic response to a warming climate can serve as an important analogue for modern warming and today's ice sheets. We present evidence from northern Svalbard of glacier re-advances during the Late Glacial-Early Holocene in hand with relative sea-level history and the occurrence of thermophilous molluscs. We argue that glacio-isostatic adjustment during the transition into the Holocene influenced ice marginal dynamics and as a result, the southern region of the Åsgardfonna ice cap persisted through the Holocene Thermal Maximum.

Fish gill surface area can keep pace with metabolic oxygen requirements across body mass and temperature

Abstract Climate warming is driving the maximum attainable size of many fish species to decrease, yet the mechanisms underlying this ‘shrinking’ phenomenon are not well understood. The gill oxygen limitation (GOL) hypothesis is perhaps the most prominent mechanistic proposition, asserting that, as fish grow, the two‐dimensional gill surface area (GSA) progressively fails to supply enough oxygen to support the continued growth of the three‐dimensional body—a process exacerbated by increased metabolism associated with warming. However, these ideas have been hotly debated owing to limited empirical understanding of how GSA develops with respect to a fish's body mass and oxygen requirements. For the first time, we addressed this knowledge gap by rearing Galaxias maculatus for 5 months at normal (15°C) and elevated (20°C) summer temperatures, with (hyperoxia) or without (normoxia) supplementary oxygen. Quantifying individual metabolic rate and GSA traits across body sizes encompassing most of the species' ontogeny, we found little evidence for a change in the proportion of GSA available per unit of metabolic rate (termed the S metric) and no improvements under hyperoxia. Importantly, at the elevated temperature where gill oxygen limitation should be most pronounced, the S metric did not change across body mass in either oxygen treatment (allometric exponents were no different from 0). These results indicate that the gills can grow in ways that support an individual's oxygen requirements, contrasting with the suggestion that size reductions of fish in response to climate warming are driven by an insurmountable geometric constraint at the gills. Read the free Plain Language Summary for this article on the Journal blog.

Landscaping of settlements in the Aral Sea disaster zone (Kazakhstan)

The role of landscaping in ameliorating the environmental conditions within settlements surrounding the Aral Sea is paramount. The primary natural constraints affecting the proliferation of plant species in the green spaces of Aralsk include low winter temperatures, elevated summer temperatures, meager precipitation, and susceptibility to windstorms. An evaluation of the species composition of tree and shrub vegetation was conducted in landscaped areas belonging to social and cultural facilities, as well on private residential property, within the municipal boundaries of Aralsk. Plantings surveyed encompassed an area of approximately 34,000 m2. 89.5% of the flora is comprised of five predominant taxa: Ulmus pumila, Populus x canadensis, Haloxylon ammodendron, Platycladus orientalis, and Acer negundo. These species demonstrate resilience to both high and low temperatures throughout the growing season, and their availability as planting material in the region further enhances their suitability. Presently, the city incorporates 31 taxa of tree and shrub species in its green spaces. Notably, Ulmus glabra, Catalpa ovata, Platanus orientalis, Hibiscus syriacus, and Prunus padus have been introduced and were not previously observed in the city. Analysis of the age distribution reveals 68.7% of young trees, underscoring ongoing landscaping efforts within the city even amid a shortage of irrigation water.

Analysis of the grouting fullness and road performance of hot-recycled semi-flexible pavement materials

In order to enhance the utilization efficiency of reclaimed asphalt pavement (RAP) and contribute to sustainable waste management, the implementation of hot recycling technique is employed to produce semi-flexible pavement materials. This research endeavor aims to scrutinize the performance characteristics of semi-flexible pavement materials manufactured through hot recycling. To attain this objective, the grout construction issue is simulated with the aid of ABAQUS software, enabling a comprehensive investigation into the impact of various load positions, surface areas, and grout heights on the horizontal and bending features of the pavement. The findings of the study indicate that the judicious incorporation of reclaimed asphalt pavement (RAP) into the hot recycled asphalt mixture as a semi-flexible pavement material exhibits an acceptable grouting rate, outstanding resistance to high temperatures, water stability, and fatigue resistance. Such exceptional properties render these materials qualified for usage in road surfaces under heavy traffic conditions, elevated summer temperatures, and other challenging utilization scenarios [1]. Moreover, it is demonstrated that higher grouting fullness contributes to superior road performance characteristics in the context of semi-flexible pavement.

Postprandial metabolism of Australian hybrid abalone (Haliotis laevigata × H. rubra) in relation to temperature and dietary protein manipulation

Understanding the physiological responses of abalone to culture conditions and nutritional inputs is paramount to maintain optimal performance under densely stocked farming conditions. High water temperature (>24 °C) is widely accepted as a key contributor to elevated summer mortality. High crude protein levels in modern abalone diets may interact with elevated water temperature to produce detrimental effects on abalone physiological processes but have received scant attention. This study measured the energy used in the digestion, absorption, and assimilation (i.e., specific dynamic action (SDA)) of hybrid abalone (Haliotis laevigata x H. rubra) after four months of acclimation to three protein levels (32, 38 and 44%) at three culture temperatures (12, 17 and 22 °C). Hybrid abalone exhibited significant stepwise increases in meal size as temperature increased from 12 through to 22 °C, contributing to significantly different SDA between the temperature treatments. Resting (standard) aerobic metabolic rate and peak metabolism (peak ṀO2) during SDA both increased with temperature, while SDA duration was lowest at 17 °C. No effect of dietary protein was observed within the temperature treatments for the SDA metrics. Abalone held at 12 °C exhibited significantly higher rates of gonad maturation, particularly among females. When 22 °C-acclimated abalone were exposed to a simulated summer heatwave up to 26 °C, they exhibited similar mortality and metabolic responses across protein treatment groups and there was a trend of steadily decreasing ṀO2 with sustained 26 °C water temperature, probably due to fasting. These results help to inform best farming practices to ensure optimal diet, growth, metabolic performance, and survival of hybrid abalone in the dynamic farm environment.

Aquatic plant wax hydrogen and carbon isotopes in Greenland lakes record shifts in methane cycling during past Holocene warming.

Predicting changes to methane cycling in Arctic lakes is of global concern in a warming world but records constraining lake methane dynamics with past warming are rare. Here, we demonstrate that the hydrogen isotopic composition (δ2H) of mid-chain waxes derived from aquatic moss clearly decouples from precipitation during past Holocene warmth and instead records incorporation of methane in plant biomass. Trends in δ2Hmoss and δ13Cmoss values point to widespread Middle Holocene (11,700 to 4200 years ago) shifts in lake methane cycling across Greenland during millennia of elevated summer temperatures, heightened productivity, and lowered hypolimnetic oxygen. These data reveal ongoing warming may lead to increases in methane-derived C in many Arctic lakes, including lakes where methane is not a major component of the C cycle today. This work highlights a previously unrecognized mechanism influencing δ2H values of mid-chain wax and draws attention to the unquantified role of common aquatic mosses as a potentially important sink of lake methane across the Arctic.

A national survey of managed honey bee colony losses in the USA: Results from the Bee Informed Partnership for 2020–21 and 2021–22

In recent years, high losses of Western honey bee (Apis mellifera) colonies have been reported in the United States. Because honey bees are important to agricultural systems, it is critical to document when high losses occur and to explore patterns of loss among beekeeper subgroups. We used a voluntary, retrospective questionnaire to ask U.S. beekeepers (backyard, sideline, and commercial) about their colony loss during the 2020–21 and 2021–22 beekeeping seasons. We found that U.S. beekeepers lost 50.8% (38.0–63.1; 95% b.CI) of their colonies in 2020–21, the highest annual (year-long) loss reported to date. During the following year, 2021–22, beekeepers lost 39.0% (31.5–47.9; 95% b.CI) of their colonies, which is close to the average of previously published annual loss rates (40.9%). In contrast to previous years, backyard beekeepers (managing 50 or fewer colonies) had an elevated summer loss across both years and commercial beekeepers (managing >500 colonies) reported “weather” as an important cause of colony loss in the summer of 2021. Our results show that severe colony losses still occur periodically. From these data on colony loss rates, it does not appear that the health of honey bee colonies in the U.S. has improved since this survey began in 2008. We suggest that research should continue to focus on stressors that beekeepers most often perceive to be leading causes of loss—Varroa destructor mites, queen issues, and weather.

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.

A long-term, dispersion normalized PMF source apportionment of PM2.5 in Atlanta from 2005 to 2019

This study assessed the effects of policy implementations and economic drivers on the identified sources of particulate pollution and their contributions to the ambient PM2.5 concentrations in Atlanta, Georgia during 2005–2019. Dispersion-normalized positive matrix factorization (DN-PMF) was applied to account for meteorological impacts on the ambient concentrations. Secondary sulfate, gasoline vehicle, diesel vehicle, biomass burning, secondary nitrate, dust/road dust, aged sea salt, copper and pyrolyzed carbon were resolved for the study period. Among them, secondary sulfate was the largest contributor to the PM2.5 mass concentrations. A substantial decrease in its concentrations was observed both after 2008 and after 2017 due to the implementation of the Georgia Multipollutant Control for Electric Utility Steam Generating Units rule in 2007 and the new Tier 3 Motor Vehicle Emission Standards in 2017. Emissions from gasoline and diesel vehicles as well as secondary nitrate also decreased after 2008. However, the reductions in gasoline and diesel emissions can be attributed to the two years of economic recession, implementation of the Georgia Gasoline Marketing Rule and regulations under the Heavy-Duty Diesel Rule. The decrease in emissions of secondary nitrate was observed after introduction of entire year control on NOx emissions promulgated by the regulations under the Clean Air Interstate rule and the Georgia NOx Emission from Electric Utility Stream Generating Units rule. Alternatively, elevated summer values were characteristic of the biomass burning, pyrolyzed carbon and dust/road dust factors. The elevated summer biomass burning emissions in 2019 were likely due to two wildfires southwest of Atlanta, while the elevated summer dust/road dust factor values were due to transported Saharan dust episodes. Identification of the copper factor at this Atlanta site was linked to the poor venting of a high-volume sampler with a copper brush motor.

Analysis of carotenoids and fatty acid compositions in Atlantic salmon exposed to elevated temperatures and displaying flesh color loss.

Tasmanian-farmed Atlantic salmon populations exhibit starvation followed by a reduced growth rate alongside reduced flesh pigmentation in response to elevated summer temperatures, which at times can exceed their optimum threshold. Here we investigated fatty acids and carotenoids of Atlantic salmon displaying three different flesh color phenotypes, using metabolomic and chemical analyses of lipids and pigments in six key tissues. Astaxanthin is mainly responsible for flesh pigmentation, while canthaxanthin is associated with carotenoid catabolism in the liver, as our findings indicate. Reduced flesh pigmentation correlated with lower levels of carotenoids across all tested tissues and clear evidence of a correlation between carotenoid and fatty acid levels in all detected fatty acid classes was observed. The reduced growth performance and flesh pigmentation are most likely due to the impact of varying levels of starvation on fatty acids and carotenoid profiles supporting the link between carotenoids and fatty acid metabolic processes.

Effects of temperature and nutrients on microscopic stages of the bull kelp (Nereocystis luetkeana, Phaeophyceae).

Warming ocean temperatures have been linked to kelp forest declines worldwide, and elevated temperatures can act synergistically with other local stressors to exacerbate kelp loss. The bull kelp Nereocystis luetkeana is the primary canopy-forming kelp species in the Salish Sea, where it is declining in areas with elevated summer water temperatures and low nutrient concentrations. To determine the interactive effects of these two stressors on microscopic stages of N. luetkeana, we cultured gametophytes and microscopic sporophytes from seven different Salish Sea populations across seven different temperatures (10-22°C) and two nitrogen concentrations. The thermal tolerance of microscopic gametophytes and sporophytes was similar across populations, and high temperatures were more stressful than low nitrogen levels. Additional nitrogen did not improve gametophyte or sporophyte survival at high temperatures. Gametophyte densities were highest between 10 and 16°C and declined sharply at 18°C, and temperatures of 20 and 22°C were lethal. The window for successful sporophyte production was narrower, peaking at 10-14°C. Across all populations, the warmest temperature at which sporophytes were produced was 16 or 18°C, but sporophyte densities were 78% lower at 16°C and 95% lower at 18°C compared to cooler temperatures. In the field, bottom temperatures revealed that the thermal limits of gametophyte growth (18°C) and sporophyte production (16-18°C) were reached during the summer at multiple sites. Prolonged exposure of bull kelp gametophytes to temperatures of 16°C and above could limit reproduction, and therefore recruitment, of adult kelp sporophytes.

Ontogenetic differences in the response of the cold-water coral Caryophyllia huinayensis to ocean acidification, warming and food availability

Cold-water corals (CWCs) are considered vulnerable to environmental changes. However, previous studies have focused on adult CWCs and mainly investigated the short-term effects of single stressors. So far, the effects of environmental changes on different CWC life stages are unknown, both for single and multiple stressors and over long time periods. Therefore, we conducted a six-month aquarium experiment with three life stages of Caryophyllia huinayensis to study their physiological response (survival, somatic growth, calcification and respiration) to the interactive effects of aragonite saturation (0.8 and 2.5), temperature (11 and 15 °C) and food availability (8 and 87 μg C L−1). The response clearly differed between life stages and measured traits. Elevated temperature and reduced feeding had the greatest effects, pushing the corals to their physiological limits. Highest mortality was observed in adult corals, while calcification rates decreased the most in juveniles. We observed a three-month delay in response, presumably because energy reserves declined, suggesting that short-term experiments overestimate coral resilience. Elevated summer temperatures and reduced food supply are likely to have the greatest impact on live CWCs in the future, leading to reduced coral growth and population shifts due to delayed juvenile maturation and high adult mortality.

539 Contact Burns Associated with Concomitant use of Methamphetamines and Heat Stroke, Resulting in Neurological Sequela

Abstract Introduction On a summer day in the desert southwest, ground surfaces can soar to 180 degrees Fahrenheit, posing significant risk to individuals who sustain contact with such surfaces, particularly if unable to get up. These individuals are also at risk for heat stroke. This summer, an increased number of patients admitted with contact burns were positive for methamphetamine and concomitant heat stroke. The purpose of this case series is to describe the hospital course and outcomes of this subset of patients. Methods A retrospective chart review of patients admitted between June and September 2022 was completed. Criteria for inclusion included contact burn, initial core body temperature > 38.8°C, and a methamphetamine positive drug screen. Outcome measures included length of stay, discharge disposition, number of operations, admission Glasgow Coma Score, neurology work-up and sequela. Results A total of 23 patients were admitted who suffered contact burns and tested positive for methamphetamine. Ten of those patients had core body temperatures greater than 38.8°C upon initial evaluation. The mean age was 36.6 years (24-62), with an average temperature of 42.3°C (40.5-43.1°. All 10 were found down in the community with altered mental status, the average Glasgow Coma Scale was 5.9 (3- 12). CT scans were done on 9, all were negative for acute intracranial abnormalities. Neurology was consulted for 3 patients with 2 having EEGs performed, both displayed slowing and attenuation secondary to hyperthermia. Ten of these patients were concurrently positive for fentanyl. The mean total burn surface area burned was 9.6% (4-17.5%), The average number of operations was 4.1/patient (1-11). Of the 8 patients discharged the average LOS was 30 days (10-61), 2 patients remain hospitalized in the ICU with a current LOS of 61-71 days. Of the 8 patients discharged, all required post-acute care with only 1 meeting rehabilitation criteria. Conclusions Elevated temperatures in the Southwestern United States have been known to cause an increase in surface-related contact burns during the summer months. Historically, the at-risk patient population has been elderly individuals prone to falls with limited physical ability to get up. This summer highlighted a new phenomenon of younger individuals suffering both contact burns and heat stroke secondary to the combination of methamphetamine use and elevated summer temperatures. This patient population suffered significant morbidity, and none were able to be discharged home. This case series highlights the dangers posed by ambiently heated surfaces during the summer months, particularly in combination with illicit drug use. Applicability of Research to Practice This case series, demonstrates the increased risk of sequela associated with burn patients who have comorbid substance abuse disorder.

Histological and transcriptomic analysis of muscular atrophy associated with depleted flesh pigmentation in Atlantic salmon (Salmo salar) exposed to elevated seawater temperatures

Tasmania is experiencing increasing seawater temperatures during the summer period which often leads to thermal stress-induced starvation events in farmed Atlantic salmon, with consequent flesh pigment depletion. Our previous transcriptomic studies found a link between flesh pigmentation and the expression of genes regulating lipid metabolism accompanied by feeding behavior in the hindgut. However, the impact of prolonged exposure to elevated water temperature on muscle structural integrity and molecular mechanisms in muscle underlying pigment variation has not been elucidated to date. In this study, we investigated the effect of prolonged exposure to elevated water temperature on the farmed salmon flesh pigmentation and structural integrity, using muscle histological and transcriptomic analysis. On April 2019, after the end of the summer, two muscle regions of the fish fillet, front dorsal and back central (usually the most and least affected by depletion, respectively), were sampled from fifteen fish (weighing approximately 2 kg and belonging to the same commercial population split in two cages). The fish represented three flesh color intensity groups (n = 5 fish per group) categorized according to general level of pigmentation and presence of banding (i.e. difference in color between the two regions of interest) as follows: high red color-no banding (HN), high red color-banded (HB) and Pale fish. Histological analysis showed a distinction between the flesh color intensity phenotypes in both muscle regions. Muscle fibers in the HB fish were partly degraded, while they were atrophied and smaller in size in Pale fish compared to HN fish. In the Pale fish, interstitial spaces between muscle fibers were also enlarged. Transcriptomic analysis showed that in the front dorsal region of the HN fish, genes encoding collagens, calcium ion binding and metabolic processes were upregulated while genes related to lipid and fatty acid metabolism were downregulated when compared to HB fish. When comparing the back central region of the three phenotypes, actin alpha skeletal muscle and myosin genes were upregulated in the HN and HB fish, while tropomyosin genes were upregulated in the Pale fish. Also, genes encoding heat shock proteins were upregulated in the HN fish, while genes involving lipid metabolism and proteolysis were upregulated in the Pale fish. Starvation, likely caused by thermal stress during prolonged periods of elevated summer water temperatures, negatively affects energy metabolism to different extents, leading to localized or almost complete flesh color depletion in farmed Atlantic salmon. Based on our results, we conclude that thermal stress is responsible not only for flesh discoloration but also for loss of muscle integrity, which likely plays a key role in pigment depletion.

Effects of elevated water temperature on cutthroat trout angler catch rates and catch‐and‐release mortality in Idaho streams

AbstractThe concern is growing that angling may need to cease at elevated summer water temperatures to protect salmonid populations. Cutthroat Trout Oncorhynchus clarkii in streams were caught, marked and released using artificial dry flies at temperatures from 13.5 to 25.7°C to evaluate whether subsequent recapture with backpack electrofishing (an index of relative survival) was reduced when the water temperature was elevated at the time of landing, and to evaluate the effect of water temperature on angler catch rates. The electrofishing recapture rate of marked fish (i.e. relative survival) declined as water temperature increased, from 0.58 for fish landed at <21°C to 0.35 at 21–23°C and 0.17 at >23°C. However, angler catch declined similarly as water temperature increased, from 5.2 fish/h at <21°C to 4.1 fish/h at 21–23°C and 1.2 fish/h at >23°C. After accounting for both declines, fish mortality/angler might be higher at cooler water temperatures than at warmer temperatures. Therefore, inhibiting fishing at elevated water temperatures may not benefit trout populations any more than at cooler temperatures.