Tropical Climate Zones Research Articles

Ciliates in different types of pools in temperate, tropical, and polar climate zones – implications for climate change

Small water bodies are typically characterized by high diversity of various groups of microorganisms. Moreover, these ecosystems react very quickly to even the slightest climate changes (e.g. a temperature increase or water level fluctuations). Thus far, studies of planktonic ciliates in small water bodies having different origins and located in various climate zones have been scarce. Our study aimed to verify the following hypotheses: planktonic ciliate assemblages exhibit higher diversity in pools with higher concentrations of biogenic compounds; pools in warmer climates have higher biodiversity of planktonic ciliates than those in the polar climate zone; individual functional groups of ciliates demonstrate considerable diversity, both between individual pool types and between climate zones. The study was conducted in 21 small pools in temperate, tropical, and polar climate zones. While the type of pool clearly influenced the makeup of microbial communities, the influence of climate was stronger. The factors with the greatest influence on the occurrence of these microorganisms were temperature, total organic carbon, and nutrients. Our results show that in warmer climates the abundance of bacterivorous ciliates is higher, while that of mixotrophs is lower. This has consequences for modelling of climate change and assessment of its influence on the carbon cycle in small water body ecosystems.

Seasonal variation in mortality and the role of temperature: a multi-country multi-city study.

Although seasonal variations in mortality have been recognized for millennia, the role of temperature remains unclear. We aimed to assess seasonal variation in mortality and to examine the contribution of temperature. We compiled daily data on all-cause, cardiovascular and respiratory mortality, temperature and indicators on location-specific characteristics from 719 locations in tropical, dry, temperate and continental climate zones. We fitted time-series regression models to estimate the amplitude of seasonal variation in mortality on a daily basis, defined as the peak-to-trough ratio (PTR) of maximum mortality estimates to minimum mortality estimates at day of year. Meta-analysis was used to summarize location-specific estimates for each climate zone. We estimated the PTR with and without temperature adjustment, with the differences representing the seasonal effect attributable to temperature. We also evaluated the effect of location-specific characteristics on the PTR across locations by using meta-regression models. Seasonality estimates and responses to temperature adjustment varied across locations. The unadjusted PTR for all-cause mortality was 1.05 [95% confidence interval (CI): 1.00-1.11] in the tropical zone and 1.23 (95% CI: 1.20-1.25) in the temperate zone; adjusting for temperature reduced the estimates to 1.02 (95% CI: 0.95-1.09) and 1.10 (95% CI: 1.07-1.12), respectively. Furthermore, the unadjusted PTR was positively associated with average mean temperature. This study suggests that seasonality of mortality is importantly driven by temperature, most evidently in temperate/continental climate zones, and that warmer locations show stronger seasonal variations in mortality, which is related to a stronger effect of temperature.

Weathering profiles developed on gneisses from Batchenga and Doua areas, central Cameroon: Climate and topography controls

Two weathering profiles from Batchenga and Doua areas in Central Cameroun developed under contrasting equatorial climate conditions and located in different morphological units have been selected to constraint the variability of their morphology, mineralogy, and geochemistry. The parent rock is a biotite and amphibole gneiss with a heterogranular granoblastic texture. The weathering profiles are typical lateritic materials formed in a humid tropical climate zone. They comprise, from bottom to top, coarse saprolite, fine saprolite, nodular horizon and loose clayey horizon. The Doua weathered materials are more clay-rich as a result of intense chemical weathering (CIA: 95.0–99.5%) than those of Batchenga (CIA: 51.3–87.8%). The weathering profile of Doua is thicker (12.00 m) than that of Batchenga (6.30 m). The intense chemical weathering and the total leaching of mobile elements as a consequence of good drainage led to the formation of a hard nodular horizon in the Doua weathering profile. The mineral composition is dominated by quartz, kaolinite, muscovite, illite, hematite/goethite, gibbsite and anatase. Illite is particularly abundant in the Batchenga weathering profile. Among trace elements, Ba, V, Zr, Sr, and Cr have high contents while REE show moderate contents with the highest contents in the Batchenga weathering profile. The oxidizing conditions favor positive Ce anomalies while positive Eu anomalies are due to the resistance of Eu mineral bearers. Geochemical mass balance results suggest that climate and topographic position which influence the quality of drainage greatly influence the distribution patterns of major, trace and rare earth elements in the weathering profiles. Apart from Al, Fe, and P, major elements have been much leached than trace elements during chemical weathering. Thus, the important variations are explained by the variation in the annual rainfall and topographic conditions.

Seasonal variation in mortality and the role of temperature: a multi-country multi-city study

BACKGROUND AND AIM: Although seasonal variations in mortality have been recognised for a long time, the role of temperature remains unclear. We aimed to assess seasonal variation in mortality and to examine the contribution of temperature. METHODS: We compiled daily data on all-cause, cardiovascular, and respiratory mortality, temperature, and indicators on location-specific characteristics from 719 locations in tropical, dry, temperate and continental climate zones. We fitted time-series regression models to estimate the amplitude of seasonal variation in mortality on a daily basis, defined as the peak-to-trough ratio (PTR) of maximum mortality estimates to minimum mortality estimates at day-of-year. Random-effects multivariate meta-analysis was used to summarise location-specific estimates for each climate zone. We estimated PTR with and without temperature adjustment, with the differences representing the seasonal effect attributable to temperature. We also evaluated the effect of location-specific characteristics on PTR across locations by using random-effects meta-regression models. RESULTS:Seasonality estimates and responses to temperature adjustment varied across locations. Unadjusted-PTR for all-cause mortality was 1.05 (95% confidence interval (CI): 1.00–1.11) in the tropical zone and 1.23 (95% CI: 1.20–1.25) in the temperate zone; adjusting for temperature reduced the PTR estimates to 1.02 (95% CI: 0.95–1.09) and 1.10 (95% CI: 1.07–1.12), respectively. Furthermore, unadjusted-PTR was positively associated with average annual mean temperature, and adjusting for temperature in PTR moved the estimate towards the null. CONCLUSIONS:This study suggests that seasonality of mortality is importantly driven by temperature, most evidently in temperate/continental climate zones, and that warmer locations show stronger seasonal variations in mortality, which is related to a stronger effect of temperature. On behalf of the MCC collaborative research network. KEYWORDS: Seasonality of mortality, temperature, a multi-country multi-city study

The pattern of kdr mutations correlated with the temperature in field populations of Aedes albopictus in China

BackgroundAedes albopictus is the primary vector of dengue fever in China. This mosquito species has a wide distribution range in China and can be found in the tropical climate zones of southern provinces through to temperate climate zones of northern provinces. Insecticides are an important control method, especially during outbreaks of dengue fever, but increasing insecticide resistance raises the risk of failure to control vector-borne diseases. Knockdown resistance (kdr) caused by point mutations in the voltage-gated sodium channel (VGSC) gene is a key mechanism that confers resistance to pyrethroids. In this study we explored the characteristics and possible evolutionary trend of kdr mutation in Ae. albopictus based on analysis of the kdr mutations in field populations of mosquitoes in China.MethodsA total of 1549 adult Ae. albopictus were collected from 18 sites in China from 2017 to 2019 and 50 individuals from three sites in the 1990s. A fragment of approximately 350 bp from part of the S6 segment in the VGSC gene domain III was amplified and sequenced. Using TCS software version 1.21A, we constructed haplotypes of the VGSC gene network and calculated outgroup probability of the haplotypes. Data of annual average temperatures (AAT) of the collection sites were acquired from the national database. The correlation between AAT of the collection site and the kdr mutation rate was analyzed by Pearson correlation using SPSS software version 21.0.ResultsThe overall frequency of mutant allele F1534 was 45.6%. Nine mutant alleles were detected at codon 1534 in 15 field populations, namely TCC/TCG (S) (38.9%), TTG/CTG/CTC/TTA (L) (3.7%), TGC (C) (2.9%), CGC (R) (0.3%) and TGG (W) (0.1%). Only one mutant allele, ACC (T), was found at codon 1532, with a frequency of 6.4% in ten field populations. Moreover, multiple mutations at alleles I1532 and F1534 in a sample appeared in five populations. The 1534 mutation rate was significantly positively related to AAT (Pearson correlation: r(18) = 0.624, P = 0.0056), while the 1532 mutation rate was significantly negatively related to AAT (Pearson correlation: r(18) = − 0.645, P = 0.0038). Thirteen haplotypes were inferred, in which six mutant haplotypes were formed by one step, and one additional mutation formed the other six haplotypes. In the samples from the 1990s, no mutant allele was detected at codon 1532 of the VGSC gene. However, F1534S/TCC was found in HNHK94 with an unexpected frequency of 100%.ConclusionsKdr mutations are widespread in the field populations of Ae. albopictus in China. Two novel mutant alleles, F1534W/TGG and F1534R/CGC, were detected in this study. The 1534 kdr mutation appeared in the population of Ae. albopictus no later than the 1990s. The F1534 mutation rate was positively correlated with AAT, while the I1532 mutation rate was negatively correlated with AAT. These results indicate that iInsecticide usage should be carefully managed to slow down the spread of highly resistant Ae. albopictus populations, especially in the areas with higher AAT.Graphical abstract

Urban Growth and Heat in Tropical Climates

This research describes the change in temperatures across approximately 270 tropical cities from 1960 to 2020 with a focus on urban warming. It associates urban growth indicators with temperature variations in tropical climate zones (tropical rainforest, tropical monsoon, and tropical wet-dry savanna). Our findings demonstrate that over time while temperatures have increased across the tropics, urban residents have experienced higher temperatures (minimum and maximum) than those living outside of cities. Moreover, in certain tropical zones, over the study period, temperatures have risen faster in urban areas than the background (non-urban) temperatures. The results also suggest that with continuing climate change and urban growth, temperatures will continue to rise at higher than background levels in tropical cities unless mitigation measures are implemented. Several fundamental characteristics of urban growth including population size, population density, infrastructure and urban land use patterns are factors associated with variations in temperatures. We find evidence that dense urban forms (compact residential and industrial developments) are associated with higher temperatures and population density is a better predictor of variation in temperatures than either urban population size or infrastructure in most tropic climate zones. Infrastructure, however, is a better predictor of temperature increases in wet-dry savanna tropical climates than population density. There are a number of potential mitigation measures available to urban managers to address heat. We focus on ecological services, but whether these services can address the projected increasing heat levels is unclear. More local research is necessary to untangle the various contributions to increasing heat in cities and evaluate whether these applications can be effective to cool tropical cities as temperature continue to rise. Our methods include combining several different datasets to identify differences in daily, seasonal, and annual maximum and minimum temperatures.

Climatic Effect on the Exergetic Performance of Conventional to Hybrid Evaporative Coolers With Varying Dead-State Temperatures in India

Abstract A comprehensive exergy, exergo-economic, and sustainability assessment of seven conventional to hybrid air-conditioning systems comprising direct and indirect evaporative coolers with direct expansion system and their several combinations integrated into an eight-story domestic building for five different cities corresponding to arid, semi-arid, humid subtropical, tropical wet and dry, and tropical wet climatic zones across India are investigated based on simulation output from energyplus. The exergetic performances are reported for varying dead state temperatures ranging from 5 °C to 40 °C, while the saturated humidity ratio and pressure at system outlet are two other dead state properties. The results reveal that the specific exergy of moist air and exergetic efficiency decreases with increasing dead state temperature and becomes least at a dead state temperature near American Society of Heating, Refrigerating and Air-conditioning Engineers (ASHRAE) comfort temperature of 23 °C. In arid, semi-arid, and humid subtropical climates, the three-stage evaporative cooling system exhibits the lowest exergy destruction of 100 J/kg1 and the highest exergy efficiency of 90% at a dead state temperature of 40 °C. The two-stage direct evaporative-direct expansion cooling system exhibits superior exergy efficiency in tropical wet and dry and tropical wet zones. Furthermore, the Grassmann diagram based on the climate of Hyderabad indicates that the three-stage cooling system is energetically and exergetically optimum with exergy destruction of 28.86%.

Quantifying diurnal and seasonal variation of surface urban heat island intensity and its associated determinants across different climatic zones over Indian cities

ABSTRACT Surface urban heat island (SUHI) is a major anthropogenic alteration of Earth’s surface and can influence the local thermal environment by altering the surface energy flux balances. Researchers have paid much attention to SUHI studies in the last decades; still, its geospatial variability over a larger area is poorly understood. Detailed research is required to understand the mechanism and dynamics of SUHI along with its different driving variables. Hence in this study, we quantified the diurnal, seasonal, and interannual variation of SUHI intensity (SUHII) over 150 major Indian cities situated over different climatic zones using MODIS data from 2003 to 2018. The results reveal urban cool islands occurrence over the hot desert, hot steppe, and tropical monsoon climatic zone during daytime in both summer (−0.25 to −0.17°C) and winter (−0.33 to 0.17°C) season. In contrast, nighttime SUHII shows clear evidence of positive urban heat island irrespective of climatic region and seasonal variation of 0.48–1°C in summer and 0.46–1.32°C in winter is seen. The Mann–Kendall and Sen’s slope estimator tests are used to detect the trend of the SUHII during the study period, which suggests a higher percentage of cities showing an increasing trend of SUHII for urban heat islands than the cities of the urban cool island. Pearson’s correlation and stepwise multiple linear regression model determine the possible SUHII controlling variable over different climatic zones. During the daytime, the SUHII’s distribution is controlled by vegetation, evapotranspiration, and thermal inertia in the summer/winter season. Whereas, it is linked tightly to built-up intensity, white sky albedo, and thermal inertia in both seasons during nighttime. Overall, we found that the stepwise multiple linear regression model can explain the SUHII variance more in the daytime (>0.8) than in nighttime (>0.7, except for tropical cities) and more in understanding the SUHII behaviors for cool cities as compared to hot cities. Moreover, this study also quantifies the significant control of thermal inertia and soil moisture in understating urban heat and cool island behavior over different climatic zones.

Characterization of nirS- and nirK-containing communities and potential denitrification activity in paddy soil from eastern China

Denitrification is important for nitrogen balance in agricultural ecosystems. It is well established that the abundance and structure of denitrifier are strongly influenced by environmental factors. However, knowledge of how nirS- and nirK-harboring microbial communities vary in paddy soils of different climatic regions is lacking, along with how these microbes are associated with denitrification potential. In this study, forty paddy soils from tropical, sub-tropical, warm-temperate, and mid-temperate climate zones were collected. The results showed that soils from the sub-tropical zone had the highest denitrification rates. The abundances of nirS and nirK had a strong negative association with C/N ratio and clearly varied among the four climate zones. Variation in nirS- and nirK-containing communities existed across sampling sites from each climate zone in terms of α- and β-diversity. Soil pH and climate factors significantly affected community diversity. Network analysis revealed that different climate regions had similar keystone taxa like Azospira, and Achromobacter, which were significantly related to denitrification rates. Structural equation modeling indicated that the differences in denitrifying enzyme activity among the four climate zones were mostly explained by climate factors, soil pH, and nirS biodiversity. Specifically, the biodiversity of nirS was more important than that of nirK in regulating potential denitrification activity in paddy soil, suggesting that nirS-type denitrifiers may have high activity under anaerobic conditions. Our results allow a deeper insight into the relative contribution of nirS- and nirK- containing communities to the soil denitrification activity in paddy soils across climate zones. This study highlighted the need of manipulation experiment to explain how denitrifier biodiversity affect potential denitrification activity in the future.

Assembly processes lead to divergent soil fungal communities within and among 12 forest ecosystems along a latitudinal gradient.

Latitudinal gradients provide opportunities to better understand soil fungal community assembly and its relationship with vegetation, climate, soil and ecosystem function. Understanding the mechanisms underlying community assembly is essential for predicting compositional responses to changing environments. We quantified the relative importance of stochastic and deterministic processes in structuring soil fungal communities using patterns of community dissimilarity observed within and between 12 natural forests and related these to environmental variation within and among sites. The results revealed that whole fungal communities and communities of arbuscular and ectomycorrhizal fungi consistently exhibited divergent patterns but with less divergence for ectomycorrhizal fungi at most sites. Within those forests, no clear relationships were observed between the degree of divergence within fungal and plant communities. When comparing communities at larger spatial scales, among the 12 forests, we observed distinct separation in all three fungal groups among tropical, subtropical and temperate climatic zones. Soil fungal β-diversity patterns between forests were also greater when comparing forests exhibiting high environmental heterogeneity. Taken together, although large-scale community turnover could be attributed to specific environmental drivers, the differences among fungal communities in soils within forests was high even at local scales.

Geographical distribution of Burkholderia pseudomallei in soil in Myanmar.

BackgroundBurkholderia pseudomallei is a Gram-negative bacterium found in soil and water in many tropical countries. It causes melioidosis, a potentially fatal infection first described in 1911 in Myanmar. Melioidosis is a common cause of sepsis and death in South and South-east Asia, but it is rarely diagnosed in Myanmar. We conducted a nationwide soil study to identify areas where B. pseudomallei is present.Methodology/Principal findingsWe collected soil samples from 387 locations in all 15 states and regions of Myanmar between September 2017 and June 2019. At each site, three samples were taken at each of three different depths (30, 60 and 90 cm) and were cultured for B. pseudomallei separately, along with a pooled sample from each site (i.e. 10 cultures per site). We used a negative binomial regression model to assess associations between isolation of B. pseudomallei and environmental factors (season, soil depth, soil type, land use and climate zones). B. pseudomallei was isolated in 7 of 15 states and regions. Of the 387 sites, 31 (8%) had one or more positive samples and of the 3,870 samples cultured, 103 (2.7%) tested positive for B. pseudomallei. B. pseudomallei was isolated more frequently during the monsoon season [RR-2.28 (95% CI: 0.70–7.38)] and less in the hot dry season [RR-0.70 (95% CI: 0.19–2.56)] compared to the cool dry season, and in the tropical monsoon climate zone [RR-2.26; 95% CI (0.21–6.21)] compared to the tropical dry winter climate zone. However, these associations were not statistically significant. B. pseudomallei was detected at all three depths and from various soil types (clay, silt and sand). Isolation was higher in agricultural land (2.2%), pasture land (8.5%) and disused land (5.8%) than in residential land (0.4%), but these differences were also not significant.Conclusion/SignificanceThis study confirms a widespread distribution of B. pseudomallei in Myanmar. Clinical studies should follow to obtain a better picture of the burden of melioidosis in Myanmar.

A checklist of spiders from Yongxing Island, South China Sea, with taxonomic notes on four species of goblin spiders.

BackgroundYongxing Island (about 1.85 km2) isthe largest island of the Xisha Islands. It is located in the Western South China Sea and belongs to the tropical ocean monsoon climate zone. Yongxing Island is quite rich in biological resources, for example, plants and birds which have been well documented. However, there are limited reports on spider resources in Yongxing Island.New informationA preliminary checklist of spiders of the Yongxing Island is provided, based on a short-term study undertaken in January 2008. A total of 23 species, belonging to 21 genera and 11 families, were recorded from the area, which forms baseline information of spiders of the Yongxing Island. Amongst these, Oonopidae, Pholcidae, Araneidae and Salticidae were found to have more species in the area. Brignolia parumpunctata (Simon, 1893), Opopaea apicalis (Simon, 1893), Opopaea deserticola Simon, 1891 and Xyphinus baehrae Kranz-Baltensperger, 2014 were firstly reported from China, for which we provide taxonomic description in this paper.

Effect of Phase Change Materials on the Thermal Performance of Residential Building Located in Different Cities of a Tropical Rainforest Climate Zone

This study aims to investigate the thermal performance of PCM and PCM combined with nighttime natural (NV) and mechanical ventilation (MV) applied to a residential building located in eight cities of tropical rainforest climate zone (Af). The analysis was accomplished using numerical simulations and developing a unique methodology for selecting the PCM melting temperature based on the thermal comfort limits. The thermal performance of the PCM integrated building was quantitatively evaluated using the concept of peak temperature drop. Additionally, a novel indicator of Total Temperature Drop (TTD) was introduced to determine the overall impact of the PCM and PCM combined with NV/MV on the thermal comfort conditions inside the building. The results showed that PCM 28 was the most efficient in improving the thermal performance of the building located in the Af climate zone, achieving a TTD of up to 356 °C per year. The usage of PCM 28 combined with nighttime natural ventilation improved the TTD values by up to 15%, whereas the integration of PCM 28 combined with mechanical ventilation resulted in a TTD values increase of up to 45%. Conclusively, mechanical ventilation showed its superiority over natural ventilation in the tropical rainforest climate, and PCM 28 applied together with mechanical ventilation could be used as the optimum combination for the whole climate zone.

Accelerating Urban Heating Under Land-Cover and Climate Change Scenarios in Indonesia: Application of the Universal Thermal Climate Index

Climate change causing an increase of frequency and magnitude of heat waves has a huge impact on the urban population worldwide. In Indonesia, the Southeast Asian country in the tropical climate zone, the increasing heat wave duration due to climate change will be also magnified by projected rapid urbanization. Therefore, not only climate change mitigation measures but also adaptation solutions to more frequent extreme weather events are necessary. Adaptation is essential at local levels. The projected increase of the heat wave duration will trigger greater health-related risks. It will also drive higher energy demands, particularly in urban areas, for cooling. New smart solutions for growing urbanization for reducing urban heat island phenomenon are critical, but in order to identify them, analyzing the changing magnitude and spatial distribution of urban heat is essential. We projected the current and future spatial variability of heat stress index in three cities in Indonesia, namely, Medan, Surabaya, and Denpasar, under climate change and land-cover change scenarios, and quantified it with the Universal Thermal Climate Index (UTCI) for two periods, baseline (1981–2005) and future (2018–2042). Our results demonstrated that currently the higher level of the UTCI was identified in the urban centers of all three cities, indicating the contribution of urban heat island phenomenon to the higher UTCI. Under climate change scenarios, all three cities will experience increase of the heat, whereas applying the land-cover scenario demonstrated that in only Medan and Denpasar, the UTCI is likely to experience a higher increase by 3.1°C; however, in Surabaya, the UTCI will experience 0.84°C decrease in the period 2018–2042 due to urban greening. This study advanced the UTCI methodology by demonstrating its applicability for urban heat warning systems and for monitoring of the urban green cooling effect, as well as it provides a base for adaptation measures’ planning.

Polycyclic aromatic compounds (PAHs, oxygenated PAHs, nitrated PAHs, and azaarenes) in air from four climate zones of China: Occurrence, gas/particle partitioning, and health risks

Polycyclic aromatic compounds (PACs) such as polycyclic aromatic hydrocarbons (PAHs) and their derivatives [oxygenated PAHs (OPAHs), nitrated PAHs (NPAHs), and azaarenes (AZAs)] are toxic and ubiquitous air pollutants. In this study, the concentrations of these PACs were determined in air obtained in spring and autumn of 2012 from urban and rural areas of the Tibetan Plateau, temperate, subtropical, and tropical climate zones in China. Average concentrations (gaseous + particulate) of ∑29PAHs, ∑15OPAHs, ∑11NPAHs, and ∑4AZAs were 928 ± 658, 54 ± 45, 5.3 ± 4.4, 14 ± 11 ng m−3 and 995 ± 635, 67 ± 38, 8.4 ± 6.1, 24 ± 16 ng m−3 in spring and autumn, respectively. Various C fractions and latitude correlated significantly with the concentrations and ratios of PACs. The slopes of the regression of gas-particle partition coefficients (Kp) of PACs on their sub-cooled liquid vapor pressures (PL0), indicated both adsorption and absorption to total suspended particles (TSP) for PAHs, OPAHs, and NPAHs in the four studied climatic zones. This result was further supported by comparing the fractions of PACs in TSP calculated from field data with those predicted by the Junge-Pankow adsorption and KOA absorption models. The concentration ratios of most OPAHs or NPAHs to their parent PAHs and of benzo[e]pyrene/benzo[a]pyrene were higher in autumn than in spring and increased with remoteness from point sources. This suggests enhanced secondary formation of PAH derivatives due to the elevated photochemical activity in autumn and longer ageing of air and associated transformation of PACs during their long-distance transport from source regions (urban sites) to rural sites. Lifetime lung cancer risk estimated from PACs ranged from 0.8 ± 0.6 to 3.1 ± 1.0 (×10−3), exceeding the value (10−5) recommended by the WHO. Gaseous PACs contributed substantially to the estimated cancer risks and their contributions increased with decreasing latitude in China.

Typical Zone Division of Karst Kevelopment in China

Determining the typical area of karst development in China would provide positive reference for theoretical research of engineering geology in karst areas in China. By quantitative or semi-quantitative analyzing on the distribution characteristics, climatic conditions and formation lithology of carbonate rocks in China, regional difference characteristics of karst development in carbonate rock regions in China is evaluated, and finnally the representative karst zone in China is reasonably and theoretically delineated and demonstrated. Results show that: the pure Carbonate rocks in southwest of China in tropical and subtropical climate zone which are very favorable for karst development, distributes continuously and massively, and therefore can be considered as the most typical karst area,. this is also a very explanation that karst morphology develops completely. Especially, karst in the zone including Guangxi Zhuang Autonomous Region, southeast and north-east of Guizhou province, and southeastern of Chongqing Municipality, is the most representative karst region in southwest of china because of its the purest carbonate rocks.

Cluster Analysis Classification of Honey from Two Different Climatic Zones Based on Selected Physicochemical and of Microbiological Parameters.

The geographical origin of honey affects its composition, which is of key importance for the health-promoting properties and safety of the product. European regulations clearly define the physicochemical requirements for honey that determine the microbiological quality. On the other hand, legislation abolishes microbiological criteria. In the study 40 honey samples originating from two different climatic zones were analyzed. The water content, pH, water activity analysis and the microbiological quality of honey samples have been tested using the reference plate method (total viable count, yeast and molds, lactic acid bacteria, Bacillus spp.). The cluster classification showed that total viable count of bacteria could be used as a measure alternative to the count of Bacillus spp. and 70% of honeys from the tropical climate zone had different microbiological quality than honeys from the temperate climate zone but still under the level 3.0 log cfu/g. The study has revealed that geographical origin of honey may significantly affect the quality and safety of honey. It was considered that water content can be the most informative and handy marker of the microbiological quality of honeys. Analysis of lactic acid bacteria showed temperate climate zone honeys as a source of beneficial bacteria in the diet.

Straw application and soil organic carbon change: A meta-analysis

Straw return is considered an effective way to improve the soil organic carbon (SOC) content of farmland. Most studies have suggested that a straw application increases the SOC content; however, some suggest that a straw application reduces the SOC content when used in combination with mineral fertilisation. Therefore, a meta-analysis of the effect of a straw application on the SOC change is needed. This study comprises a meta-analysis of 115 observations from 65 research articles worldwide. Straw applications can significantly increase the proportion of the SOC in the soil. Straw applications caused a significant microbial biomass carbon (MBC) increase in tropical and warm climatic zones. The MBC increase was higher than the SOC increase. For agriculture, the most important soil functions are the maintenance of the crop productivity, the nutrient and water transformation, the biological flora and activity, and the maintenance of the microbial abundance and activity. These functions should be prioritised in order to maintain the SOC function and services. Straw applications should not be excessive, especially when combined with mineral fertilisation, in order to avoid the loss of carbon from the straw in the form of greenhouse gases. A large amount of unused fertiliser also leads to a series of environmental problems.

Test and application of the geochemical lithogene on weathering profiles developed over granitic and basaltic rocks in China

Geochemical gene is a new technique presented recently and its property needs to be tested. Two weathering profiles developed over granitic and basaltic rocks were sampled and analyzed in Dunhua area in Northeast China with a cool temperate monsoon climate. Based on their major and trace elemental compositions, the geochemical lithogene numbered as LG01 was coded and samples' gene similarities were calculated relative to their parent rocks and top soils respectively. According to the similar gene criterion of ≥80% on gene similarity, the geochemical lithogene LG01 shows not only good heredity (on similar gene from parent rock to top soil) but also good inheritance (on similar gene from top soil to parent rock) in each weathering profile. That is to say, the geochemical lithogene LG01 illustrates good stability during weathering. According to the composition classification method based on the acidic similarity (a gene similarity relative to the acidic rock with the LG01 gene of 10202020202), the weathered products of the profile developed over granite are acidic-like composition (with acidic similarity of ≥80%) and those formed on basalt are basic-like composition (with acidic similarity of ≤20%). These indicate the validity of the composition classification method based on the geochemical lithogene LG01. In order to test the property and application of LG01 in a wider range, four newly reported weathering profiles (a granitic profile and a basaltic profile located in a warm temperate monsoon climate zone, another granitic profile in a subtropical monsoon climate zone, and another basaltic profile in a tropical monsoon climate zone) were also discussed. Their results verify the conclusion that the geochemical lithogene LG01 not only illustrates good stability among samples due to rock weathering but also is a potential tool on classification of rocks and their weathered products.

Improvement on Window Glassing for an Enhanced Indoor Thermal Environment of Tropical Office Buildings

The intense solar radiation absorbed through the window glassing and transmitted into the indoor environment constitute thermal discomfort and increased cooling energy demand for buildings in the tropical climatic zone. This is because tropical climates are generally characterised by hot thermal distress almost all the year round. The need for improvement on window glassing of office buildings arise as a result of the global consensus on reducing energy demand of building sector. In office buildings, higher level of thermal and visual comfort is required for productive work performance within the indoor environment. This place office buildings in a position to enhance the realisation of a sustainable environment in the tropical climatic zone. This paper focus on effect of two types of window glassing on indoor air temperature and achieving improvement on single pane ordinary clear glassing window through the use of low-solar gain low-emissivity windows of two existing office buildings in the warm-humid zone of the tropical climate of Nigeria. An experimental investigation was scheduled during rainy and dry seasons of the year to collect outdoor and indoor microclimatic data of air temperatures in the west-facing natural ventilated office spaces within the existing office buildings through the use of Tiny Tag Ultra 2 Dual Channel Temperature/Relative Humidity (TGU-4500) Data loggers. Data collected were sorted and analysed through descriptive statistics. Improvement on single glassing window of existing office building was obtained through calculation of heat gain characteristics and comparison with that of low-solar gain low-emissivity glass window heat gain characteristics. Results showed that single pane ordinary clear glassing window exhibits higher indoor temperatures in the monitored office space. 89.54% improvement was recorded by using low-solar gain low-emissivity glass window over single pane clear glass window in the investigated office buildings. The study therefore recommends the use of low-solar gain glass low-emissivity window in office buildings within the warm-humid zone of tropical climate of Nigeria.