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The impact of climate change on global biodiversity is firmly established, but the differential effect of climate change on populations within the same species is rarely considered. In ectotherms, melanism (i.e. darker integument due to heavier deposition of melanin) can significantly influence thermoregulation, as dark individuals generally heat more and faster than bright ones. Therefore, darker ectotherms might be more susceptible to climate change. Using the colour-polyphenic lizard Karusasaurus polyzonus (Squamata: Cordylidae), we hypothesized that, under future climatic projections, darker populations will decrease their activity time more than brighter ones due to their greater potential for overheating. To test this, we mechanistically modelled the body temperatures of 56 individuals from five differently coloured populations under present and future climate conditions. We first measured morphological traits and integumentary reflectance from live animals, and then collected physiological data from the literature. We used a biophysical model to compute activity time of individual lizards as proxy for their viability, and thereby predict how different populations will cope with future climate conditions. Contrary to our expectations, we found that all populations will increase activity time and, specifically, that darker populations will become relatively more active than bright ones. This suggests that darker populations of K. polyzonus may benefit from global warming. Our study emphasizes the importance of accounting for variation between populations when studying responses to climate change, as we must consider these variations to develop efficient and specific conservation strategies. A free Plain Language Summary can be found within the Supporting Information of this article.

Transpiration is a key component of the watershed water budget. Therefore, determining the transpiration of forest stands with different characteristics have been of interest for watershed hydrology and forest management practices in a wide range of environments. The objectives of this study were to compare transpiration of Anatolian black pine (Pinus nigra Arn. subsp. pallasiana (Lamb.) Holmboe) and sessile oak (Quercus petraea (Matt.) Liebl.) tree stands and to model transpiration based on the measured climatic factors. Stand transpirations were calculated from sap flow measurements made by the trunk heat balance method. We conducted an exploratory factor analysis (PCR) to detect affecting meteorological factors of stand transpiration, and we developed linear regression equations to predict transpiration of pine and oak stands. Mean daily and yearly canopy transpiration (Ec) were 1.05 mm day(-1) and 378.3 mm year(-1) for the pine stand and 3.52 mm day(-1) and 801.7 mm year(-1) for the oak stand. There was a highly positive correlation between daily stand transpiration and wind speed, global radiation, air vapour pressure deficit and air temperature, but a negative correlation with relative humidity for both stands. Soil water potential had little effect on stand transpiration. The model equations accounted for 81% of the variations in transpiration for the pine stand and 85% for the oak stand. Therefore, the transpiration of forest stands should be considered for effective vegetation management practices, as model equations to estimate the transpiration of pine and oak stands in the region. Istanbul University Scientific Research Projects UnitIstanbul University [52494] The study was financed by the Istanbul University Scientific Research Projects Unit with project number 52494. The authors are grateful to Mr Jiri Kucera from Environmental Measuring Systems (Brno, Czech Republic) and Prof. Jan Cermak from Mendel University (Brno, Czech Republic) for their help and contribution in the design of the study, obtaining the necessary sensors and field measurements. The authors thank Mr Sebahattin Serhat Turgut for his help in PCR analyses; they also thank Prof. Ferhat Gokbulak from Istanbul University for his helpful comments on the manuscript.

Shallow Antarctic surface lakes belong to the most extreme aquatic environments on the Earth. In Vestfjella, proglacial surface lakes and ponds are characterized by a 2–5 month long period with liquid water and depths < 2 m. We give a detailed description of nine seasonal lakes and ponds situating at three nunataqs (Basen, Plogen and Fossilryggen) in western Dronning Maud Land. Their physical and geochemical properties are provided based on observations in four summers. Three main ‘lake categories‘ were found: 1) supraglacial lakes, 2) epiglacial ponds and 3) nunataq ponds. Category 3 lakes can be divided into two subgroups with regards to whether the meltwater source is glacial or just seasonal snow patches. Supraglacial lakes are ultra-oligotrophic (electrical conductivity < 10 μS cm−1, pH < 7), while in epiglacial ponds the concentrations of dissolved and suspended matter and trophic status vary over a wide range (electrical conductivity 20–110 μS cm−1, pH 6–9). In nunataq ponds, the maxima were an electrical conductivity of 1042 μS cm−1 and a pH of 10.1, and water temperature may have wide diurnal and day-to-day fluctuations (maximum 9.3°C) because snowfall, snow drift and sublimation influence the net solar irradiance.

Modern internal combustion engines fired with natural gas offer comparatively low installation costs, long life, good efficiency characteristics, and show reliable performance in power applications. Additional positive features such as short delivery times, quick start-up, and retained high efficiency at part-loads have made gas engines the preferred choice for many small- to medium-scale power plants. Wärtsilä’s gas engine portfolio offers several well-proven engine models optimised for stationary power applications in the size range from 4 to 8.7 MWe, and two dual-fuel gas-diesel engine modifications of 6 MWe and 16.6 MWe. There is a rising interest in combined cycle mode engines with possibly higher electrical efficiencies, at locations where heat energy is not needed or where electricity prices inspire investments in maximum power production. Various types of bottoming cycles can be applied to utilise the waste energy streams from the main engine and deliver additional power output. The basic hurdle though is the low electrical efficiency of the bottoming cycle due to low temperature levels of the engine waste energy streams, and the consequent low economic performance of the bottoming cycle hardware, which in itself can often require investment costs close to those for the main engine. Therefore, more efficient bottoming cycle alternatives should be examined, as well as a better optimisation and thermodynamic/economic evaluation of those should be performed in order to find an applicable solution. The work presented herein concentrates on heat-balance simulations and thermodynamic evaluation of conventional cold-condensing steam bottoming cycles optimised for high electrical efficiency utilizing the waste energy streams from the W20V34SG gas engine of 8730 kWe net power output. Highest possible electrical efficiency for the combined cycle is sought, i.e. the bottoming cycle is configured and designed to match the given topping engine and to utilize the exergy content of the engine’s exhaust streams in the best possible way, while using only conventional steam technology with standard components, and applying a slightly optimistic approach with regards to isentropic efficiencies, generator efficiencies, steam condenser conditions, and heat-exchanger effectiveness. Steam bottoming cycles of varying complexity have been simulated and evaluated with the help of computer simulations based on the heat-balance software product ProSim. The simulation results show that the net electrical power output of the steam bottoming cycle alone can reach from around 847 kWe (i.e. 9.7% of the main engine power output) for the simplest single-pressure cold-condensing configuration, up to 1270 kWe for a very complex yet practical configuration, which is 14.5% of the main engine output. The electrical efficiency of the combined cycle can reach up to 50.8 % LHV and even more, which is a 6 %-point increase above that of the main engine in single-cycle operation. QC 20120217

A number of authors have suggested that hyperthermia, the elevation of body temperature (T-b) 2 degrees-4 degrees C above normal, contributes to a reduction in total evaporative water loss (TEWL) in birds. Information about the role of hyperthermia in the water economy of birds is scattered throughout the literature. We purposed to collate the available information on this subject, to reevaluate the benefits and costs of this process, and to assess its net effect on the water economy of birds, especially species living in deserts. In this review, we first consider the current model of heat balance in birds at high ambient temperatures (T-a), and show that, in most studies performed at a high T-a, birds were increasing their T-b, a violation of the assumption of steady state conditions. Next, we incorporate the rate of heat gain into calculations of the dry heat transfer coefficient (h), below and above temperature equality (T-a = T-b). We develop a method to calculate h at T-a = T-b, using l'Hopital's rule. The combined result of our approach suggests that birds increase their dry heat transfer even when T-a is above T-a = T-b, contrary to our prediction. Finally, we explore aspects of hyperthermia that reduce water loss, such as an improved thermal gradient and heat storage, and aspects that may augment water loss, the latter a result of increased respiratory water loss when T-b is elevated. Our analysis of the combination of these three factors suggests that, during acute exposure to high T-a (1 h), birds over a size range of 10-1,000 g save about 50% of their TEWL by becoming hyperthermic. For chronic episodes of high T-a (5 h), small birds save water by hyperthermia but large birds do not.