Seasonal Temperature Variations Research Articles

New tree-ring data from Canadian boreal and hemi-boreal forests provide insight for improving the climate sensitivity of terrestrial biosphere models

Understanding boreal/hemi-boreal forest growth sensitivity to seasonal variations in temperature and water availability provides important basis for projecting the potential impacts of climate change on the productivity of these ecosystems. Our best available information currently comes from a limited number of field experiments and terrestrial biosphere model (TBM) simulations of varying predictive accuracy. Here, we assessed the sensitivity of annual boreal/hemi-boreal forest growth in Canada to yearly fluctuations in seasonal climate variables using a large tree-ring dataset and compared this to the climate sensitivity of annual net primary productivity (NPP) estimates obtained from fourteen TBMs. We found that boreal/hemi-boreal forest growth sensitivity to fluctuations in seasonal temperature and precipitation variables changed along a southwestern to northeastern gradient, with growth limited almost entirely by temperature in the northeast and west and by water availability in the southwest. We also found a lag in growth climate sensitivity, with growth largely determined by the climate during the summer prior to ring formation. Analyses of NPP sensitivity to the same climate variables produced a similar southwest to northeast gradient in growth climate sensitivity for NPP estimates from all but three TBMs. However, analyses of growth from tree-ring data and analyses of NPP from TBMs produced contrasting evidence concerning the key climate variables limiting growth. While analyses of NPP primarily indicated a positive relationship between growth and seasonal temperature, tree-ring analyses indicated negative growth relationships to temperature. Also, the positive effect of precipitation on NPP derived from most TBMs was weaker than the positive effect of precipitation on tree-ring based growth: temperature had a more important limiting effect on NPP than tree-ring data indicated. These mismatches regarding the key climate variables limiting growth suggested that characterization of tree growth in TBMs might need revision, particularly regarding the effects of stomatal conductance and carbohydrate reserve dynamics.

Seasonality shapes community structure and functional group dynamics of zooplankton in Changjiang River estuary and its adjacent waters

AbstractAimFunctional trait‐based approach links the zooplankton community to the marine ecosystem functioning. It provides a comprehensive insight into the diversity of zooplankton ecological strategies but has rarely been used to characterize the zooplankton community in estuarine ecosystem. Here, we investigated the seasonality of mesozooplankton functional structure with respect to environmental changes in Changjiang River estuary (CRE) and its adjacent waters.LocationChangjiang River estuary and its adjacent waters.MethodsSamples were collected in three seasons of 2019. Morphologically identified species were assigned functional traits including body length, feeding strategy, trophic group, reproduction mode and habitat type, and clustered into functional groups. Taxonomic and functional diversity indices were calculated. The relative importance of the environmental variables in explaining the seasonality of functional structures was assessed.ResultsTen functional groups were identified, and functional structure showed strong seasonal dynamics. Current‐ and mixed‐feeding omnivore–herbivores were the predominant group over seasons. The contribution of carnivorous, detritivorous and omnivorous groups increased from winter–spring to autumn. The seasonality of zooplankton functional structure was mainly explained by the effect of temperature, fluvial discharge and warm current. Low temperature and riverine input of nutrient in winter–spring favoured the small‐sized herbivores. Subsequently, the rising temperature and run‐off in summer shifted the zooplankton community to larger herbivores and carnivores. Moderate temperature and relatively enhanced effect of warm current promoted the proliferation of carnivores and detritivores in autumn. Functional diversity also varied over seasons.Main conclusionsThe functional dynamics of mesozooplankton in CRE across estuarine gradient and seasonality is shaped by the seasonal variation of temperature, fluvial pulse and warm current intrusion. Our findings pave the way for further understanding estuarine biodiversity and have implications in conservation strategies.

Multiscale Analysis of Naturally Weathered High-Voltage XLPE Cable Insulation in Two Extreme Environments

Crosslinked polyethylene (XLPE) insulation is widely used in power cables because of its excellent properties. Due to the remoteness of end users, the energy is generally transported over long distances. These cables cross various areas being sometimes exposed to different environmental stresses that affect their performance and increase their degradation. While most published literatures are limited to laboratory scales, this article uniquely deals with a multiscale analysis of a 30 months naturally weathered XLPE samples in two harsh environments. The first site is a marine environment with high humidity level, sea salt content in the air, seasonal variation of temperature, and concomitant radiation doses. The second one is a desert environment characterized by extremely high temperatures, which reached 50 °C during summer, coupled with thermal cycling and large solar radiation doses with UV rays of high energy wavelengths. Modifications in the XLPE insulation characteristics due to weathering were studied using different experimental techniques. The testing matrices included dielectric and mechanical characterization, scanning electron microscopy (SEM), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, and differential scanning calorimetry (DSC) measurements on fresh and weathered XLPE insulation samples. It is found that the degradation rate was faster in the arid desert climate compared with the coastal one. Furthermore, correlation mechanisms between the obtained results are discussed in order to better understand the weathering degradations.

UK battery electric bus operation: Examining battery degradation, carbon emissions and cost

This paper examines the impact of geographical location on the energy consumption of double deck battery electric buses operating in four UK cities. By considering seasonal variation in ambient temperature and an assumed battery degradation process, the implications on operational cost and carbon emissions were investigated. Using a MATLAB/Simulink model the total energy demand of a vehicle operating on the UKBC was simulated. Energy consumption was combined with hourly seasonal averages of carbon intensity (gCO2/kWh) and wholesale electricity costs (£) to assess charging at different times of the day and year. At the beginning of life, the range could decrease by up to 17.3% due to heating load requirements. From beginning of life to end of life, range was predicted to decrease by up to 26%. Whilst the average operational costs are relatively consistent across the four regions, the average carbon emissions can be five times higher depending on location.

The Geologic Impact of 16 Psyche’s Surface Temperatures

NASA’s Discovery mission Psyche will soon be launched to visit the asteroid 16 Psyche. In this work, we model the surface temperatures of 16 Psyche. Our modeling is focused on capturing the diurnal and seasonal surface temperature variations caused by 16 Psyche’s large obliquity (95°) and moderately high eccentricity (0.134). Using a semianalytic framework, we predict that large thermal variations (including at the poles) can cause cracking of boulders leading to a porous surface regolith. This prediction is consistent with a high-porosity surface regolith inferred from thermal inertia measurements. We also find that water ice is not likely to be stable at any latitude.

TEMPERATURE AND SALINITY CHARACTERISTICS IN THE SOUTHERN SOUTH CHINA SEA AND STRAIT OF MALACCA

Temperature and salinity characteristics in the southern South China Sea and Strait of Malacca are investigated using CTD data and the global ocean model HYCOM. CTD data were obtained from cruises taken in March 2015, March 2019, and July-August 2019. The results showed that the average reading of temperature and salinity in the Strait of Malacca during March 2015 was 28.60±0.708 °C and 32.61±1.01 psu, respectively. The average readings during March 2019 were 29.31±1.593 °C and 32.38±0.884 psu, respectively. The average temperature and salinity in the Strait of Malacca during the August 2019 cruise were 29.63±0.701 °C and 32.52±0.553 psu, respectively. Meanwhile, in the southern South China Sea, the average readings in July 2019 were 28.98±0.310 °C and 33.07±0.126 psu and in August 2019 were 27.94±1.01 °C and 33.36±0.363 psu. Seasonal variations presented by the 15-years (1997-2012) HYCOM climatological model show that the sea surface temperature is warmer by approximately 1 - 2 °C during the southwest monsoon months (June-July-August) than during the northeast monsoon (December-January-February) in the southern South China Sea. The seasonal temperature variations in the Strait of Malacca are not significant except for the southern part. The sea surface salinity exhibits no clear seasonal cycle except for the coastal areas.

The seafloor heat flux driven by bottom water temperature variation in the Yellow and Bohai Seas

The Yellow and Bohai Seas (YBS) are shallow marginal seas located at the temperate latitudes of the western North Pacific. The seasonal bottom water temperature variation in the YBS can be greater than 20 °C and therefore generates significant seafloor heat flux, which significantly changes both the sediment temperature profile and heat content of the overlying water column. In this study, we investigated the seafloor heat flux driven by bottom water temperature variation in the YBS using a high-resolution numerical ocean model and a one-dimensional sediment temperature model. The results showed that seafloor heat flux in the area shallower than 50 m was on the order of 10 W/m2. The seafloor heat flux was larger than the lateral heat flux driven by circulation and ranked second only to surface net heat flux accounting for the most important forcing mechanism of ocean heat content variation in the coastal YBS. The accumulated seafloor heat flux during the sediment cooling/warming season could warm/cool the overlying water column by about 1 °C in the coastal YBS where the depth is shallower than 30 m. The depth of sediment affected by seafloor heat flux (seasonal sediment temperature variation >0.1 °C) could be as deep as 10 m. The complex spatial–temporal distribution of seafloor heat flux generated a complex distribution of sediment temperature and sound speed, which may have an important effect on acoustic wave propagation in the YBS.

Year-Round Thermal Error Modeling and Compensation for the Spindle of Machine Tools Based on Ambient Temperature Intervals.

The modeling and compensation method is a common method for reducing the influence of thermal error on the accuracy of machine tools. The prediction accuracy and robustness of the thermal error model are two key performance measures for evaluating the compensation effect. However, it is difficult to maintain the prediction accuracy and robustness at the desired level when the ambient temperature exhibits strong seasonal variations. Therefore, a year-round thermal error modeling and compensation method for the spindle of machine tools based on ambient temperature intervals (ATIs) is proposed in this paper. First, the ATIs applicable to the thermal error prediction models (TEPMs) under different ambient temperatures are investigated, where the C-Means clustering algorithm is utilized to determine ATIs. Furthermore, the prediction effect of different numbers of ATIs is analyzed to obtain the optimal number of ATIs. Then, the TEPMs corresponding to different ATIs in the annual ambient temperature range are established. Finally, the established TEPMs of ATIs are used to predict the experimental data of the entire year, and the prediction accuracy and robustness of the proposed ATI model are analyzed and compared with those of the low and high ambient temperature models. The prediction accuracies of the ATI model are 20.6% and 41.7% higher than those of the low and high ambient temperature models, respectively, and the robustness is improved by 48.8% and 62.0%, respectively. This indicates that the proposed ATI method can achieve high prediction accuracy and robustness regardless of the seasonal temperature variations throughout the year.

Utilization of Community Science Data to Explore Habitat Suitability of Basal Termite Genera

AbstractThe advent of community-science databases in conjunction with museum specimen locality information has exponentially increased the power and accuracy of ecological niche modeling (ENM). Increased occurrence data has provided colossal potential to understand the distributions of lesser known or endangered species, including arthropods. Although niche modeling of termites has been conducted in the context of invasive and pest species, few studies have been performed to understand the distribution of basal termite genera. Using specimen records from the American Museum of Natural History (AMNH) as well as locality databases, we generated ecological niche models for 12 basal termite species belonging to six genera and three families. We extracted environmental data from the Worldclim 19 bioclimatic dataset v2, along with SoilGrids datasets and generated models using MaxEnt. We chose Optimal models based on partial Receiving Operating characteristic (pROC) and omission rate criterion and determined variable importance using permutation analysis. We also calculated response curves to understand changes in suitability with changes in environmental variables. Optimal models for our 12 termite species ranged in complexity, but no discernible pattern was noted among genera, families, or geographic range. Permutation analysis revealed that habitat suitability is affected predominantly by seasonal or monthly temperature and precipitation variation. Our findings not only highlight the efficacy of largely community-science and museum-based datasets, but our models provide a baseline for predictions of future abundance of lesser-known arthropod species in the face of habitat destruction and climate change.

Physiological responses and adjustments of corals to strong seasonal temperature variations (20-28°C).

Temperature is a key driver of metabolic rates. So far, we know little about potential physiological adjustments of subtropical corals to seasonal temperature changes (>8°C) that substantially exceed temperature fluctuation experienced by their counterparts in the tropics. This study investigated the effect of temperature reductions on Montastraea cavernosa and Porites astreoides in Bermuda (32°N; sea surface temperature ∼19-29°C) over 5 weeks, applying the following treatments: (i) constant control temperature at 28°C, and (ii) temperature reduction (0.5°Cday-1) followed by constant temperature (20 days; acclimatization period) at 24°C and (iii) at 20°C. Both species decreased photosynthesis and respiration during temperature reduction as expected, which continued to decrease during the acclimatization period, indicating adjustment to a low energy turnover rather than thermal compensation. Trajectories of physiological adjustments and level of thermal compensation, however, differed between species. Montastraea cavernosa zooxanthellae metrics showed a strong initial response to temperature reduction, followed by a return to close to control values during the acclimatization period, reflecting a high physiological flexibility and low thermal compensation. Porites astreoides zooxanthellae, in contrast, showed no initial response, but an increase in pigment concentration per zooxanthellae and similar photosynthesis rates at 24°C and 20°C at the end of the experiment, indicating low acute thermal sensitivity and the ability for thermal compensation at the lowest temperature. Respiration decreased more strongly than photosynthesis, leading to significant build-up of biomass in both species (energy reserves). Results are important in the light of potential poleward migration of corals and of potential latitudinal and species-specific differences in coral thermal tolerance.

Acclimation of Ecophysiological and Agronomic Traits to Increasing Growth Temperature in Three Cowpea Genotypes Grown in Anuradhapura, Sri Lanka

The future of food crop production is uncertain due to the negative effects of global warming. Cowpea is grown in warm environments including in Sri Lanka, where less is known about the potential acclimation of ecophysiological and agronomic traits to increasing temperatures. We evaluated the acclimation potential of yield components and ecophysiological traits of three recommended cowpea genotypes to the seasonal variation in growth temperature in Anuradhapura, Sri Lanka. This study was conducted at the Faculty of Agriculture, Rajarata University of Sri Lanka, in two consecutive seasons with average daytime temperatures of 30.4°C and 33.2°C. Three genotypes, Dhawala, Waruni, and MI-35, were tested in this study, and their rates of leaf photosynthesis and respiration at the 50% flowering stage and final yield parameters were measured at their respective average growth temperatures in both seasons. The total yield per hectare showed an average decrease of 16%, 17%, and 22% in the Dhawala, Waruni, and MI-35 genotypes at high average growth temperature, respectively. These reductions were associated with the reduction in the number of seeds per pod, hundred seed weight, and number of pods per plant, suggesting that there could be an among-genotype variation in flower abscission, fertilization, and biomass partitioning during the season in which the average growth temperature was high. In the season with high average growth temperature, genotype Dhawala showed an increased carbon gain per unit carbon loss and increased water use efficiency compared to MI-35 and Waruni genotypes. Therefore, genotype Dhawala is a better candidate than MI-35 and Waruni genotypes in the face of global warming, which may be considered in further breeding programs and market preferences. More work is proposed to examine the patterns of biomass partitioning and radiation use efficiency in three cowpea genotypes at elevated temperatures.

Information entropy‐based projection of temperature variability under the warming trend in China

AbstractQuantifying the predictability of temperature in the future is a priority to inform policy and adaptation planning. Based on information entropy theory, this study uses global climate models within the Coupled Model Intercomparison Project Phase 6 (CMIP6) to project spatiotemporal changes and variability of temperature in China in the 21st century under different shared socio‐economic pathway scenarios (SSP2‐4.5 and SSP5‐8.5). Results show that the multimodel ensembled values can accurately capture the spatiotemporal pattern of temperature in China. The warming rates of annual mean temperature in China under SSP2‐4.5, SSP5‐8.5 scenarios are 0.42 and 0.61°C·decade−1 in the near‐term (2021–2050), 0.20 and 0.87°C·decade−1 in the long‐term (2071–2100), respectively. Warming is found to be the greatest in winter. Northeast, northwest, and the first region of southwest are anticipated to increase particularly rapidly, with larger increases than the rest of China. The intrayear variability of temperature (the variability of monthly mean temperature within the year or different seasons) in China shows obvious latitudinal differences. The variability of monthly mean temperature exhibits a decreasing trend in parts of northeast and the first region of southwest, and an increasing trend in northwest and parts of north. This is mainly resultant from the variability of monthly mean temperatures within spring and autumn. And this trend is more significant under the SSP5‐8.5 scenario than that under the SSP2‐4.5 scenario. The interannual variability of temperature (the variability of annual or seasonal mean temperature) in China shows significant regional difference, and two obvious regions with extreme variability (northeast and the first region of southwest). The trend of variability increases and then decreases under the SSP2‐4.5 scenario, whereas it keeps increasing under the SSP5‐8.5 scenario. This study helps to understand the spatiotemporal characteristics of temperature variability in China in the 21st century.

Influence of the advection of water masses in the Ballenas Channel on the CO[formula omitted] system in Bahía de los Angeles (Mexico)

The surface waters of the Ballenas Channel (BC) are characterized by thermohaline and biogeochemical conditions that depend on the water masses present. Since these surface waters are transported into Bahía de los Ángeles (BLA), it is relevant to assess their timing, intensity and biogeochemical implications on a seasonal scale. For this purpose, the seasonal and spatial variability of temperature, salinity, dissolved inorganic carbon (DIC) and total alkalinity (TA), were quantified over 19 discrete monthly monitoring campaigns that covered 12 stations in BLA from June 2017 to October 2019. In addition, vertical CTD profiles of thermohaline, apparent oxygen utilization (AOU), and nitrate were obtained for the purposes of identifying the water masses present and determining how they change by season. It was found that the dynamics of DIC, AOU, nitrate, and temperature in BLA respond to the presence of Subtropical Subsurface Water (SSW), evident by the enrichment of the bay with high DIC and nitrate concentrations during winter, but during summer occurs the opposite, with the presence of the Gulf of California Water (GCW). In addition, zonation analysis within BLA indicated three regions consistently found along the year, attributed to different physical and biogeochemical processes. Finally, we also interpreted the data in the context of the interannual variability due to ENSO events by using a relationship between observed temperature–DIC data. A 20-year calculated DIC (DICcalc) time series for an area near BLA indicated that during summer periods under the influence of La Niña events, the DICcal in front to BLA could be 10-12μmol kg −1 higher than El Niño events. These high DIC values, likely promoted by an increased volume of SSW in the BC, is accompanied by a higher nutrients concentration, suggesting that the interannual variability must interact with biological processes within BLA and other adjacent embayment’s in this region.

Importance of the seasonal temperature and precipitation variation on glacial evolutions during the LGM at monsoonal Himalaya based on Cogarbu valley

Glacier models have played a more and more important role in reconstructing the paleoglacier and paleoclimate, but the detailed analysis based on high spatial and temporal resolution simulations is rare. In this study, we deeply analyzed the paleoglacial evolution on seasonal scale and its relationship with the large-scale circulation shifts during the Last Glacial Maximum (LGM) in Cogarbu valley, a typical monsoon influence region, using the Open Global Glacier Model driven by 12 Global Circulation Models and their average. The paleoglacier reconstructed under the mean climate is closer to the observations, with the glacier length, area, and volume of 19.8 km, 35.7 km2, and 6.6 km3, respectively. The reconstructed equilibrium-line altitude is ~5253 m, about 662 m lower than modern. The temperature has a 4.6 °C decreasing with a 16.3% reduction of precipitation. The seasonal temperature decreases about −4.0, −4.6, −4.2, and − 5.5 °C in spring, summer, autumn, and winter, respectively. Detailed analysis on atmospheric circulation shifts indicates that the high correlation of temperature change between TP and North Atlantic Ocean might be caused by their similar response to the global climate change results from the reduction of insolation rather than baroclinic waves. In summer, southward-shifted and narrowed the Intertropical Convergence Zone weakened the Indian Summer Monsoon, decreasing the summer precipitation of −22.4% compared to modern. In winter, the enhancement of the South Branch of Westerlies increased the winter precipitation of 10.0%. Despite more winter precipitation refueled the glacial accumulation, the decreasing of the summer temperature has dominant influence on the annual net surface mass balance via reducing the summer ablation during the LGM.

A STUDY ON USE OF WASTE POLYTHYLENE IN BITUMINOUS PAVEMENT MIXES

Bituminous mixes are most ordinarily used everywhere the planet in versatile pavement construction. It consists of asphalt or hydrocarbon (used as a binder) and mineral combination that are mixed along, ordered down in layers so compacted. below traditional circumstances, conventional hydrocarbon pavements if designed and dead properly perform quite satisfactorily however the performance of hydrocarbon mixes is incredibly poor below varied things. Today’s mineral concrete pavements are expected to perform higher as they're experiencing increased volume of traffic, inflated hundreds and inflated variations in daily or seasonal temperature over what has been intimate within the past. additionally, the performance of bituminous pavements is found to be terribly poor in wetness iatrogenic things. Considering this a great deal of labor has been done on use of additives in hydrocarbon mixtures and still as on modification of hydrocarbon. analysis has indicated that the addition of polymers to asphalt binders helps to extend the surface cohesiveness of the bond between the combination and the binder which may enhance several properties of the asphalt pavements to assist meet these increased demands. However, the additive that's to be used for modification of combine or binder should satisfy each the strength needs still as economical aspects. Plastics are all over in today’s mode and are growing quickly throughout significantly in a developing country like Bharat. As these are non-biodegradable there's a significant drawback posed to the society with reference to the management of those solid wastes. rarity polyethylene (LDPE) has been found to be a decent modifier of hydrocarbon. Even, the saved polyethylene originally fabricated from LDPE has been determined to switch hydrocarbon. within the gift study, a shot has been created to use saved polythene that has been obtained from plastic packets utilized in packaging of a really common whole of milk named OMFED, in dry form with the aggregates sort of a fibre in an exceedingly hydrocarbon combine. careful study on the results of these regionally waste polythene on engineering properties of hydrocarbon concrete (BC), iii Dense hydrocarbon macadam (DBM) and Stone mastic asphalt (SMA) mixes, has been created in this study. The present regionally on the market OMFED polythene used as stabilizer in SMA, BC and DBM mixes to fulfil this need of paving mixes. Optimum binder content (OBC) and optimum polythene content (OPC) are derived by victimization Marshall Procedure. The OBCs are found to be four-dimensional for SMA and four.5% for each BC and DBM by victimization stone dust as filler. By replacement some gradation of fine combination by coarse furnacescum and ash as filler the OBCs are found to be five-hitter of hydrocarbon for SMA and fourdimensional of bitumen for each BC and DBM mixes. Similarly, OPC has been found to be a pair of by weight of mixes for SMA and DBM and one.5% for BC mixes wherever stone dirt has been used as filler. After replacement of some gradation of fine combination by scum and considering ash as filler the OPCs are found to be one.5% of polythene for every type of mixes. Then considering OBC and OPC, the SMA, BC, and DBM mixes are ready and totally different performance take a look as like Drain down test, Static indirect durability take a look at and Static Creep take a look at have been distributed to judge the results of polythene as Associate in Nursing stabilizer on combine properties. It is complete from gift investigation that addition of OMFED polythene to mixes improve the mix properties like Marshall Stability, Drain down characteristics and indirect tensile strength.

Long‐term trends and seasonal variation in host density, temperature, and nutrients differentially affect chytrid fungi parasitising lake phytoplankton

Abstract Parasites are generally considered the most commonly occurring type of consumers, yet their biomass and population dynamics are rarely quantified at community level. Here, we used 12 years of weekly or fortnightly monitoring data (518 time points) to determine the occurrence of chytrids, fungal parasites of phytoplankton, to assess their seasonality and long‐term (seasonally‐detrended) dynamics in the pelagic plankton community of a temperate, eutrophic, and polymictic lake. Chytrid infections were observed in c. 75% of all samples with recurrent infections in multiple host taxa. Infection prevalence was highest in spring, but infections occurred throughout the entire year with an average of 2.3 host taxa infected per time point (ranging from 0 to 10 host taxa) and an average infection prevalence of 2.78% (ranging from 0% to 47.35%). Infected host biomass equalled that of the carnivorous zooplankton and decreased over time, while infection prevalence remained unchanged. Seasonal infection prevalence increased with phytoplankton biomass, but decreased with increasing temperature and phosphorus concentrations, reflecting that peak prevalence occurred in spring when temperature and phosphorus concentrations were relatively low. In contrast, seasonally‐detrended prevalence increased with temperature, but decreased with increasing phosphorus concentrations. Chytrids are a common component of the pelagic plankton community with sizeable biomass and removing an—at times—substantial proportion of the primary production, challenging the long‐standing underrepresentation of parasites in ecological studies. Chytrids responded differentially to seasonal variation and long‐term trends in host density, water temperature and nutrient availability, highlighting the need to disentangle seasonal signals from long‐term changes.

Bioclimatic Envelopes for Two Bat Species from a Tropical Island: Insights on Current and Future Distribution from Ecological Niche Modeling

Bats perform critical ecosystem functions, including the pollination, seed dispersal, and regulation of invertebrate populations. Yet, bat populations are declining worldwide primarily due to habitat loss and other anthropogenic stressors. Thus, studies on bat ecology, particularly on environmental determinants of bat occupancy, are paramount to their conservation. High mobility, nocturnal behavior, and roosting site selection of bats make conventional surveys challenging. Moreover, little is known about geographic distribution, habitat suitability, and responses to climate change among tropical bat species. To bridge these research gaps, we applied ecological niche modeling to two Ceylonese bat species, Kerivoula malpasi and Kerivoula picta, to map their geographic distribution. Seasonal variations in temperature and precipitation were critical environmental predictors of bat distribution in general. Southwestern lowland forests contained the most optimal habitats for the relatively wide-ranging Kerivoula picta, while the central highlands provided the most suitable habitats for the narrow-ranging Kerivoula malpasi. No tangible changes in the highly suitable habitats were evident in response to projected climate change for either species. Yet, the optimal ranges of K. malpasi can become fragmented in the future, whereas the most optimal habitats for K. picta are likely to become spatially contiguous in the future. Habitat availability or fundamental niche alone is insufficient to reliably forecast species persistence, thus we caution against considering these two bat species as resilient to climate change. Our findings will enable the conservation authorities to initiate preemptive conservation strategies, such as the establishment of landscape-scale habitat connectivity and management of buffer zones around conservation lands. We also encourage conservation authorities to employ ecological niche models to map potential species distributions and to forecast range shifts due to climate change.

Influence of physical environmental parameters on the abundance of Chrysichthys nigrodigitatus of the Cross River, Nigeria.

In this study, the influence of physical environmental factors (rainfall, temperature, water depth, turbidity, transparency and conductivity) on the temporal distribution, abundance and catch of C. nigrodigitatus from the Cross River was investigated. Fish catch and abundance were monitored fortnightly for 12 months. Surface water samples were collected twice monthly and analyzed using standard methods. Seasonal variations in rainfall, water depth, temperature, turbidity, transparency and conductivity were observed across the study period. Correlation analysis showed a positive and significant relationship between rainfall and fish catch (P<0.05), while temperature and conductivity were negatively correlated with fish catch (P<0.05 and 0.01 respectively). Transparency was negatively correlated with fish catch but this relationship was, however, not statistically significant (P>0.05). On the other hand, water depth and turbidity were positively correlated with fish catch but again both relationships were not statistically significant (P>0.05). These findings suggest that rainfall, temperature, conductivity and other environmental variables play important role(s) in the distribution and abundance of Chrysichthys nigrodigitatus in the Cross River, with implication of climate change impact on the species reproductive ecology and population dynamics.

Consistent heat tolerance under starvation across seasonal morphs in Mycalesis mineus (Lepidoptera: Nymphalidae)

Heat tolerance is a key trait for understanding insect responses to extreme heat events, but tolerance may be modulated by changes in food availability and seasonal variability in temperature. Differences in sensitivity and resistance across life stages are also important determinants of species responses. Using a full-factorial experimental design, we here investigated the effects of larval starvation, adult starvation, and seasonal morph (developmental temperature) on heat tolerance of a seasonally polyphenic butterfly, Mycalesis mineus, in both larval and adult stages. While starvation and rearing temperature profoundly influenced various life history traits in the insect, none of the treatments affected adult heat tolerance. There was also no evidence of reduced heat tolerance in larvae under starvation stress, though larval thermal tolerance was higher by ~1 °C at the higher developmental temperature. The lack of a starvation effect was unexpected given the general physiological cost of heat tolerance mechanisms. This might be attributed to the ability to tolerate heat being preserved under resource-based trade-offs due to its critical role in ensuring insect survival. Invariant heat tolerance in M. mineus shows that some insects may have thermal capacity to cope with extreme heat under short-term starvation and seasonality disruptions, though more prolonged changes may have greater consequences. The capacity to maintain key physiological function under multiple stressors will be crucial for species resilience in future novel environments.

Temperature mediated the balance between stochastic and deterministic processes and reoccurrence of microbial community during treating aniline wastewater

Seasonal temperature changes significantly affect microbial community diversity, composition, and performance in wastewater treatment plants. However, the community assembly mechanisms under seasonal temperature variations remain unclear. Here, we carried out temperature cycling experiments (30 °C, 35 °C, 37 °C, 40 °C, 42 °C, 45 °C, 40 °C, and 30 °C) to investigate how temperature impacts microbial performance and co-occurrence network and how assembly processes determine the structure and function of microbial communities during treating aniline wastewater. During the 195-day operation, the system achieved an efficient and stable aniline removal of 99%. Interestingly, α-diversity and network complexity were negatively correlated with temperature but could be recovered when the temperature was returned to 30 °C. The results showed that functional redundancy was probably responsible for the excellent microbial performance during the whole process. Null model analyses presented that deterministic process dominated the community when the temperature was 30 °C, and stochasticity dominated the assembly process when the temperature was over 30 °C. Overall, the balance between stochastic and deterministic processes in the treatment of aniline wastewater mediated the reoccurrence of microbial community and co-occurrence network at different temperatures. This study provides new insights into microbial community reoccurrence under seasonal temperature changes and a theoretical basis for regulating microbial communities in wastewater treatment plants.