Reduction In Water Temperature Research Articles

Cortisol and glucose responses in juvenile striped catfish subjected to a cold shock

Cold-shock stress happens when a fish had been adjusted to a specific water temperature or range of temperatures and is consequently exposed to a rapid drop in temperature, resulting in a cascade of physiological and behavioral responses and, in some cases, death. In the current study, the stress response of striped Catfish (Pangasianodon hypophthalmus) was studied by evaluating serum cortisol and glucose level following an abrupt reduction in water temperature (from 28°C to 15°C) at different time points (prior to, and after 1h, 12h and 24h cold treatment, respectively). Regardless of some mortality occurred in cold challenged fish, none of the physiological parameters changed during evaluation period. The results, suggesting that despite of necessity of cortisol and glucose evaluation in any of stress assessment, yet, due to their high variability in different fish species, additional complementary tests such as measurement of other stress hormones e.g. heat shock proteins as well as blood-cell counts (preferably in chronic experiments) should also be included.

Modified tide gate management for enhancing instream habitat for native fish upstream of the saline limit

Tide and flood gates are used widely throughout the world to facilitate drainage of lowland areas and provide flood protection to valuable agricultural land and human infrastructure. However, these structures can impact on aquatic communities by disrupting connectivity and altering physical habitat conditions. Complete removal is rarely feasible in the short-term because of the competing flood mitigation and land use interests. However, in many cases it is likely that the structure and/or its operation can be modified to enhance connectivity for migratory species and reduce the severity of impacts on instream habitats.This study describes the results of a short-term trial investigating the effects of modified tide gate management on instream habitat and fish communities in a small tidal stream in the North Island of New Zealand. The study site was located upstream of the saline limit and thus does not directly address this potential limitation on managing the effects of some tide gates. The main objective of the study was to understand whether improvements in tidal flushing could mitigate the negative effects of tide gates on upstream habitats, thus improving their suitability for native fish communities.The trial demonstrated that in impacted lowland river reaches, the reintroduction of limited tidal exchange upstream of tide gates reduced negative impacts on instream habitat by restoring hydrological variability, increasing minimum dissolved oxygen concentrations and potentially also reducing water temperatures. However, it was also shown that the recovery may not be uniform and can be dependent on interactions with other stressors. The trial illustrated the potential for using modified tide gate management to mitigate the environmental effects associated with their operation, and to restore habitat conditions so that they are more favourable for the persistence of native fish species.

Field testing hot water temperature reduction as an energy-saving measure – does the Legionella presence change in a clinic's plumbing system?

Legionella spp. represent a significant health risk for humans. To ensure hygienically safe drinking water, technical guidelines recommend a central potable water hot (PWH) supply temperature of at least 60°C at the calorifier. In a clinic building we monitored whether slightly lowered temperatures in the PWH system led to a systemic change in the growth of these pathogens. In four separate phases we tested different scenarios concerning PWH supply temperatures and disinfection with chlorine dioxide (ClO2). In each phase, we took 5 sets of samples at 17 representative sampling points in the building's drinking water plumbing system. In total we collected 476 samples from the PWH system. All samples were tested (culture-based) for Legionella spp. and serogroups. Additionally, quantitative parameters at each sampling point were collected, which could possibly be associated with the presence of Legionella spp. (Pseudomonas aeruginsoa, heterotrophic plate count at 20°C and 36°C, temperatures, time until constant temperatures were reached, and chlorine dioxide concentration). The presence of Legionella spp. showed no significant reactions after reducing the PWH supply temperature from 63°C to 60°C and 57°C, as long as disinfection with ClO2 was maintained. After omitting the disinfectant, the PWH system showed statistically significant growth rates at 57°C. PWH temperatures which are permanently lowered to less than recommended values should be carefully accompanied by frequent testing, a thorough evaluation of the building's drinking water plumbing system, and hygiene expertise.

Planting grass filter strips: Does it influence the structure and function of riparian habitats of agricultural headwater streams?

AbstractGrass filter strips are strips of cool or warm season grasses planted adjacent to agricultural streams to reduce nutrient, pesticide, and sediment input. This conservation practice is the most frequently planted riparian buffer type in the United States. Previous studies have not evaluated how grass filter strips alter the structure and function of riparian habitats of agricultural streams. Our objective was to examine the research hypothesis that planting grass filter strips will influence the structure and function of riparian habitats of channelized agricultural headwater streams. We sampled riparian vegetation, quantified coarse particulate organic matter input and nutrient input, and measured water temperature within two unplanted riparian habitat sites, two riparian habitat with grass filter strips sites, and two forested riparian habitat sites of agricultural headwater streams in central Ohio. Forested riparian habitats exhibited greater percent maximum frequency of woody vegetation and reduced water temperatures than unplanted riparian habitats and grass filter strips. Forested riparian habitats also exhibited greater canopy cover, woody vegetation taxa richness, and coarse particulate organic matter input than grass filter strips and greater riparian widths and woody vegetation abundance than unplanted riparian habitats. Grass filter strips did not differ in structure and function from unplanted riparian habitats. We conclude that planting grass filter strips does not influence the structure and function of riparian habitats of channelized agricultural headwater streams.

Riparian forest as a management tool for moderating future thermal conditions of lowland temperate streams

Predictions of future climate suggest that stream water temperature will increase in temperate lowland areas. Streams without riparian forest will be particularly prone to elevated temperature. Planting riparian forest is a potential mitigation measure to reduce water temperature for the benefit of stream organisms; however, no studies have yet determined the combination of shading (% canopy cover) and stream length required to obtain a timely temperature decrease. We measured the temperature in 5 small Danish lowland streams from June 2010 to July 2011, all showing a sharp transition between an upstream open reach and a downstream forested reach. At each site we also measured canopy cover and a range of physical variables characterising the stream reach to analyse differences in mean daily temperature and amplitude per month among forested and open reaches, annual temperature regimes, and the influence of physical conditions on temperature changes. In July, water temperature increased over the entire length of the open reach in 3 of the 5 streams, reaching temperatures higher than the incipient lethal limit for brown trout (Salmo trutta). In 4 of the streams, July temperature decreased within 100 m of the stream entering the forested area, and in 3 of our study streams the temperature continued to decrease within the forested reach, without reaching a plateau. Daily temperature variation was greater in the open reaches than the forest reaches. Regression analysis indicated that temperature changes along the forested reach in July were significantly related to canopy cover, width:depth ratio, and temperature of the water entering the forested reach. We conclude that even relatively short stretches (100-500 m) of forest alongside streams may reduce water temperature and so combat the negative effects of temperature increases on stream ecology. Although forestation can be a useful mitigation measure, many lowland streams are historically rich in macrophytes, which are important hotspots for fish and macroinvertebrates. If managers leave open reaches interspersed in the riparian canopy, loss of diversity provided by these macrophyte beds could be diminished while still leaving cooler water refugia.

Change structure of cooling towers with deletion cellulose pads (packing) and air blower and use vacuum mechanism

Abstract. Topics studied in this project are to change the structure of wet cooling towers that are used in refrigerating industry. Base of working in all existing wet cooling is on upgrading heat exchange between air and cooling liquid and increasing surface evaporation and more contact between water and air. Generally, in cooling towers heated water by pipes is moved to the top of the tower. In this route water has heat exchange ventilator with outgoing air, is cooled and collected in bottom of the tower. In order to increase the contact area between water and air in the course of water falling, special packing that cellulose pad is the most common type of it is used. Cooling towers available have disadvantages such as: precipitation, corrosion of internal components, the growth of algae and biological bacteria, occupy too much space, too much noise, do not use in damp, dust in the system, not using towers together, reducing cooling efficiency over time and etc. Now if circumstances arise that tower can work in a closed cycle, in a small space, away from light, with more efficiency, longer life and different structure is ideal. Now the present project attempt is by reducing the pressure on the water surface in a closed container, increase water evaporation rate. And by using an evaporation tower, Shower, electrical controllers, alternative mechanisms and exhaust valves saturated steam, to achieve substantial cold in absence of cellulose pads and blower pump and greatly reduce water temperature Also flaws in the cooling towers such as reduction in cooling efficiency due to precipitation and decrease in performance of cellulose pads, failure to use several cooling towers next to each other, the entry of dust into the system, a lot of space, algae and biological bacteria , a lot of noise, water falling from the towers and on the ground in the surrounding space, high maintenance costs to be eliminated or minimized. The empirical research shows that due to structure designed with the placement of 0.04 atmospheric pressure on the surface of the water. In terms of sustainability, water outlet temperature is in range of 24 ° C and this means an increase in efficiency of about 30 percent compared to existing models.

Factors affecting spatiotemporal benthic macroinvertebrate diversity and secondary production in a semi-arid watershed

Spatial and temporal changes of the benthic macroinvertebrate (BMI) community composition and secondary production provide valuable information about the current ‘health’ of aquatic systems. We analyzed seasonal and inter-annual changes in BMI communities at five sites along an elevation and land use gradient in the Walker River, NV, USA. In addition, bimonthly collections of Baetis mayflies were made at two sites to assess the effect of nutrient enrichment on Baetis secondary production. BMI community composition changed spatially and temporally in response to the physicochemical environment. BMI diversity was positively correlated to substrate size and stream width but negatively correlated with stream temperature and organic pollutants. Cluster analysis based on BMI community composition revealed a similar community structure along the river, except at one site which was located below the outflow of a eutrophic reservoir. The BMI community in the river was dominated by collector–gatherers while shredders were absent through most of the downstream and impaired sites. Secondary production of Baetis was almost twice as high at the nutrient-enriched site (1.3 g dry mass m−2 yr−1) than at the undisturbed site (0.7 g m−2 yr−1), most likely the consequence of warmer water temperatures and superior food quality. Results from this study imply that a variety of anthropogenic activities have altered disparate reaches of the Walker River and that BMI community composition would change towards natural conditions with an increase in discharge and reduced water temperature and nutrients. This work also underscores the importance of considering biotic indices and secondary production to effectively assess stream ecosystem health and to design successful restoration strategies.

Dietary plant oils delay early sexual maturation compared with marine fish oil in male European seabass (Dicentrarchus labrax) — Effects on testis histology and key reproductive hormones

Sexual precocity in farmed European seabass is correlated to reduced growth and flesh quality, and is one of the major challenges for the industry. We evaluated the effects of one marine (M) and one plant (P) oil mix, supplemented at 2 dietary inclusion levels, low (LF) and high (HF), on sexual maturation of European sea bass males. The feeding experiment was conducted on maturing unsexed fish kept in indoor tanks at 10:14 LD photoperiod and reducing water temperatures from October to December. Fish performance of all the fish population, males and females, testis histology, blood hormone levels and gene expression of selected sexual maturation related hormones in the brain and testis of male fish were studied. European seabass males fed the marine oil diets had higher mRNA expressions levels of Cyp 11b, Cyp 19a and Kiss2 in both brain and testis tissues compared with male fish fed plant oil diets. Moreover, high expression of brain Kiss receptor gene (Kissr4) was found in males fed a plant oil diet suggesting a late recrudescence phase of maturation (stages III & IV) in these groups. Histological analyses of testis were in agreement with the hormone gene expression observations where male fish fed with plant oil diets were in early to mid-maturing phase (stages III–IV), while marine oil fed males were at mid to late maturing phase (stages IV–V). No significant effects were observed between the low or high dietary fat treatments. The present results suggest that supplementing diets with plant oils delays maturation in male European seabass.

Facilitating upstream passage of small-bodied fishes: linking the thermal dependence of swimming ability to culvert design

Fish passage through road culverts is poorly understood, particularly for small-bodied fishes, despite this information being integral to the restoration of waterway connectivity. We assessed the prolonged swimming performance of a small-bodied fish, empire gudgeon (Hypseleotris compressa; 3.2–7.7 cm total length, TL), and juvenile Australian bass (Percalates novemaculeata; 3.5–7.8 cm TL). Swimming trials were conducted in a hydraulic flume across a range of fixed and increasing velocities in response to acute and long-term thermal treatments. A new statistical approach (Tobit analysis) was used to relate the thermal dependence of swimming endurance to hydraulic characteristics of culverts, providing estimates of maximum water velocity allowing upstream fish passage. Reductions in water temperature of 10°C, similar to those caused by cold-water releases from dams, significantly impaired critical swimming speeds of both species. Traversable water-velocity models identified H. compressa as a weak swimmer, requiring very low water velocities (≤0.10 m s–1 or 2.86 body lengths (BL) s–1) for unrestricted passage, whereas P. novemaculeata was predicted to traverse water velocities of ≤0.39 m s–1 or 12.12 BL s–1. Culvert designs can be improved by limiting water velocities to accommodate weak-swimming fishes and by accounting for the thermal sensitivity of swimming performance.

Fish recruitment in rivers with modified discharge depends on the interacting effects of flow and thermal regimes

Summary Alteration of flow and thermal regimes is a key consequence of human use of river and floodplain ecosystems, and these impacts result from a range of interacting ecological mechanisms. Environmental flow regimes are a management strategy to restore or maintain ecologically important aspects of river hydrology. However, inadequate understanding of the processes that determine the effects of flow on population dynamics of biota hinders the maximum benefits of environmental flows. Spawning and recruitment of riverine fish is mediated by temperature, access to nursery habitat and the timing and availability of resources. Differences in population sizes between regulated and unregulated rivers are often attributed to the effect of flow and thermal regime change on population dynamics. Dams and extraction of water have altered the flow and thermal regimes of rivers in the northern Murray–Darling Basin, Australia. Combining three studies, we (i) examined differences in the recruitment of fish and patterns of potential prey availability between a regulated and unregulated river, (ii) studied the relationships between patterns of flow and temperature on spawning of fish in two rivers with contrasting regulated flow regimes and (iii) experimentally tested the effects of environmental flow releases in a regulated river on fish spawning and recruitment by comparing patterns over time against two unregulated rivers. Comparisons between regulated and unregulated rivers indicated that the significantly lower recruitment of Macquaria ambigua in the regulated river was linked with large differences in available prey. Species‐specific differences in the abundance of fish larvae between two regulated rivers indicated that different reproductive strategies determine population‐level responses to flow regulation. Finally, the experimental flow releases in a regulated reach during late spring did not result in a change in spawning and recruitment of fish, although influences of antecedent flow and temperature on larval and juvenile assemblage composition were significant. These findings indicate that the responses of fish spawning and recruitment to flow regime change and restoration are dependent on the conditions that determine the success of these critical life‐history processes. Specifically, key effects of flow regulation are reduced summer water temperatures due to hypolimnetic discharge from dams, and the reduced frequency and duration of low flows. Reduced water temperatures limit opportunities for fish to spawn, and sustained base flows were associated with lower densities of potential prey sources in conjunction with potential flushing of larvae and juveniles, thereby influencing recruitment. The benefits of environmental flow programmes can be enhanced if flow regimes are modified to ensure that abiotic and biotic conditions that support persistence of biota are provided. In conjunction with flow pulses and floods, low flows are a natural and ecologically important component of flow regimes, particularly in dryland rivers. Understanding the interactive and mechanistic effects of flow and thermal regimes on population viability and patterns of biodiversity is critical to maximising the value of environmental flows.

Mainstreaming Carbon Management in Healthcare Systems: A Bottom-Up Modeling Approach

Increasing greenhouse gas emissions threaten human health and the environment. In response, healthcare managers face significant challenges in balancing operational decisions about patient care with carbon mitigation targets. We explore a bottom-up modeling framework to aid in the decision-making for both carbon and cost in healthcare, using data from a case study in Cornwall, UK. A model was built and run for secondary healthcare, specifically outpatient clinics, theater lists, beds, and diagnostic facilities. Five scenarios were tested: business-as-usual; service expansion; site closure; water temperature reduction; and theater optimization. The estimated emissions from secondary healthcare in Cornwall ran to 5787 T CO(2)eq with patient travel adding 2215 T CO(2)eq. Closing selected sites would have reduced this by 4% (261 T CO(2)eq), a reduction less than the resulting increases in patient transport emissions. Reducing hot water temperatures by 5 °C and improving theater usage would lower the footprint by 0.7% (44 T CO(2)eq) and 0.08% (5 T CO(2)eq), respectively. We consider bottom-up models important tools in the process of estimating and modeling the carbon footprint of healthcare. For the carbon reduction targets of the healthcare sector to be met, the use of these bottom-up models in decision making and forward planning is pivotal.

Reduction of Water Temperature in Paddy Field and Leaf Temperature by Continuous Irrigation with Running Water during Nighttime

Reduction of Water Temperature in Paddy Field and Leaf Temperature by Continuous Irrigation with Running Water during Nighttime

Managing uncertainty in thermal water quality trading programs

Abstract Thermal water quality trading is an emerging policy tool that allows thermal polluters to comply with effluent restrictions by paying nearby landowners to plant shade trees. We created a system dynamics model of a hypothetical thermal trading program and conducted scenario analysis to study how weather, climate, and trading behavior might influence program effectiveness. It is likely that neither thermal trading nor conventional regulation can reduce water temperatures to desired levels, but the model indicates that trading ratios, used to account for uncertainty, lead programs to decrease water temperatures below those produced through conventional regulation.

Effects of simulated cold fronts on the survival and behaviour of yellow perchPerca flavescensyolk-sac fry

Acute reductions in water temperature (i.e. cold fronts) may influence larval fish survival directly via limits on physiological tolerance or indirectly by acting as a sublethal stressor. The primary objective was to quantify survivorship of yellow perch yolk-sac fry exposed to two different temperature declines (4 and 8°C) and compare survivorship to that of perch fry under ambient temperatures representative of natural conditions. Behaviour of yolk-sac fry following temperature declines was also qualitatively assessed. Mean survival in the control, −4, and −8 treatment tanks was 90, 91 and 97%, respectively, and no significant differences in percent survival were observed between the control and the −4 treatment (ts = −0.10; df = 7; P = 0.93), the control and −8 treatment (ts = −1.85; df = 7; P = 0.11) or the −4 and −8 treatments (ts = −1.33; df = 7; P = 0.22). Observations of yellow perch eggs and fry behaviour following temperature declines differed among treatments. Any remaining eggs in the control treatment and −4 treatments continued to hatch during the experiment, and fry were documented swimming throughout the water column in all tanks. However, in the −8 treatment, any eggs that had not hatched remained inactive and all fry within all −8 treatment tanks ceased swimming activity and settled to the bottom of the tanks once the temperature reached 3.9°C. Fry remained at the bottom of the tanks for the entire 48 h simulated cold-front. Fry resumed swimming activity once water temperatures began to increase (by approximately 6°C). Results indicated that drops in temperature (i.e. cold fronts) similar to or greater than those found in small impoundments did not cause direct mortality of yellow perch during the yolk-sac fry (post-hatch larvae) stage. Although an acute drop in temperature may not induce sudden high mortality, it may be a sub-lethal stressor, leading to increased starvation or predation risk.

Note: Compact helical pulse forming line for the generation of longer duration rectangular pulse

The helical pulsed forming line (PFL) can generate longer duration rectangular pulse in a smaller length. A compact PFL using helical water line is designed and experimentally investigated. The impedance of the helical PFL is 22 [ohm sign]. The compactness is achieved in terms of reduction in length of the PFL by a factor of 5.5 using helical water PFL as compared to coaxial water PFL of same length. The helical PFL was pulsed charged to 200 kV using a high voltage pulse transformer in 4.5 μs and discharged into the matched 22 Ω resistive load through a self-breakdown pressurized spark gap switch. The rectangular voltage pulse of 100 kV, 260 ns (FWHM) is measured across the load. The effect of reduction in water temperature on the pulse width is also studied experimentally. The increase in pulse width up to 7% more is observed by reducing the temperature of the deionized water to 5 °C. It will further reduce the length of the PFL and make the system small for compact pulsed power drivers.

Amino acids downregulate the expression of several autophagy-related genes in rainbow trout myoblasts

Many fish species experience long periods of fasting often associated with seasonal reductions in water temperature and prey availability or spawning migrations. During periods of nutrient restriction, changes in metabolism occur to provide cellular energy via catabolic processes. Muscle is particularly affected by prolonged fasting as proteins of this tissue act as a major energy source. However, the molecular components involved in muscle protein degradation as well as the regulatory networks that control their function are still incompletely defined in fish. The present work aimed to characterize the response of the autophagy-lysosomal degradative pathway to nutrient and serum availability in primary culture of rainbow trout myoblasts. In this aim, 4-day-old cells were incubated in a serum and amino acid-rich medium (complete medium), a serum and amino acid-deprived medium (minimal medium) or a minimal medium plus amino acids, and both the transcription-independent short-term response and the transcription-dependent long-term response of the autophagy-lysosomal degradative pathway were analyzed. We report that serum and amino acids withdrawal is accompanied by a rapid increase of autophagosome formation but also by a slower induction of the expression of several autophagy-related genes (LC3B, gabarapl1, atg4b). We also showed that this latter response is controlled by amino acid (AA) availability and that both TOR-dependent and TOR-independent pathways are involved in this effect. Together these results suggest an important role for AA released by muscle proteolysis during the fasting period in regulating the subtle balance between using proteins as disposable furniture to provide energy, and conserving muscle through protein sparing.

Movement patterns of smallmouth and largemouth bass in and around a Lake Michigan harbor: The importance of water temperature

Smallmouth bass Micropterus dolomieu and largemouth bass M. salmoides in southwestern Lake Michigan use shallow, warm harbors for spawning during spring. After the reproductive period ends in early summer, catch rates from standardized sampling of smallmouth bass in harbors decrease. Fishes are presumed to use the main lake during summer but little is known about how black basses use main-lake habitat in Lake Michigan or mechanisms driving this transition. We tracked smallmouth bass (N=26) and largemouth bass (N=8) using radio and acoustic telemetry during 2005–2006 near North Point Marina, IL. A temperature difference persisted between inside and outside the harbor for much of May–October where harbor temperatures were generally warmer than those outside the harbor. Smallmouth bass responded to water temperature changes, inhabiting the harbor until temperatures outside the harbor approached 18.5°C, at which time they left the harbor. Frequent temperature fluctuations of >3°C occurred outside the harbor within 24-hour periods. Sudden reductions in water temperature were associated with smallmouth bass temporarily returning to the harbor until the temperature outside the harbor again approached 18.5°C. As water cooled during fall, smallmouth bass again returned to the harbor. Largemouth bass exhibited comparatively restricted movements during this time and rarely ranged outside the harbor. Thus, home range estimates for smallmouth bass (142.6ha) were an order of magnitude greater than those of largemouth bass (12.9ha). Both water temperature and species played a role in determining the degree of movement outside the harbor but both black basses used the harbor as a thermal refuge.

Perceptions of tap water temperatures, scald risk and prevention among parents and older people in social housing: A qualitative study

BackgroundYoung children and older people are particularly vulnerable to tap water scalding. For children, there are also socio-economic inequalities in risk. Evidence suggests that reducing tap water temperatures in social (public) housing through ‘passive’ means is effective in reducing risk. However, little is known about parents’ or older people's perceptions of scald risk and prevention. ObjectivesThis study aimed to document the views of parents and older residents in social housing in an inner-London borough about their tap water temperature, perceived scalding risk and scald prevention strategies. MethodsAnalysis of twenty in-depth interviews with 11 parents and 10 people aged 65 years or older. ResultsTap water was described as very hot, but participants did not consider themselves at risk, viewing scald prevention as a personal responsibility achieved with a range of everyday, routine strategies. Very hot water was preferred for health- and convenience-related reasons. However, it was felt that others, particularly children, could be scalded, and some concern was expressed about the environmental and financial impacts of excessively hot water. ConclusionsThose seeking to introduce engineering-based scald prevention interventions in social housing should emphasise the potential environmental and financial impacts of water temperature reduction, in addition to promoting safety benefits for vulnerable others.

Cutaneous vascular and core temperature responses to sustained cold exposure in hypoxia

We tested the effect of hypoxia on cutaneous vascular regulation and defense of core temperature during cold exposure. Twelve subjects had two microdialysis fibres placed in the ventral forearm and were immersed to the sternum in a bathtub on parallel study days (normoxia and poikilocapnic hypoxia with an arterial O(2) saturation of 80%). One fibre served as the control (1 mM propranolol) and the other received 5 mM yohimbine (plus 1 mM propranolol) to block adrenergic receptors. Skin blood flow was assessed at each site (laser Doppler flowmetry), divided by mean arterial pressure to calculate cutaneous vascular conductance (CVC), and scaled to baseline. Cold exposure was first induced by a progressive reduction in water temperature from 36 to 23°C over 30 min to assess cutaneous vascular regulation, then by clamping the water temperature at 10°C for 45 min to test defense of core temperature. During normoxia, cold stress reduced CVC in control (-44 ± 4%) and yohimbine sites (-13 ± 7%; both P < 0.05 versus precooling). Hypoxia caused vasodilatation prior to cooling but resulted in greater reductions in CVC in control (-67 ± 7%) and yohimbine sites (-35 ± 11%) during cooling (both P < 0.05 versus precooling; both P < 0.05 versus normoxia). Core cooling rate during the second phase of cold exposure was unaffected by hypoxia (-1.81 ± 0.23°C h(-1) in normoxia versus -1.97 ± 0.33°C h(-1) in hypoxia; P > 0.05). We conclude that hypoxia increases cutaneous (non-noradrenergic) vasoconstriction during prolonged cold exposure, while core cooling rate is not consistently affected.

Engineering a future for amphibians under climate change

Summary 1. Altered global climates in the 21st century pose serious threats for biological systems and practical actions are needed to mount a response for species at risk. 2. We identify management actions from across the world and from diverse disciplines that are applicable to minimizing loss of amphibian biodiversity under climate change. Actions were grouped under three thematic areas of intervention: (i) installation of microclimate and microhabitat refuges; (ii) enhancement and restoration of breeding sites; and (iii) manipulation of hydroperiod or water levels at breeding sites. 3. Synthesis and applications. There are currently few meaningful management actions that will tangibly impact the pervasive threat of climate change on amphibians. A host of potentially useful but poorly tested actions could be incorporated into local or regional management plans, programmes and activities for amphibians. Examples include: installation of irrigation sprayers to manipulate water potentials at breeding sites; retention or supplementation of natural and artificial shelters (e.g. logs, cover boards) to reduce desiccation and thermal stress; manipulation of canopy cover over ponds to reduce water temperature; and, creation of hydrologoically diverse wetland habitats capable of supporting larval development under variable rainfall regimes. We encourage researchers and managers to design, test and scale up new initiatives to respond to this emerging crisis.