Wet Season Research Articles

Assessment on major browse feed resources and determine their chemical composition in Korhaye zone, Somali Region, Ethiopia

Assessment of major browse feed resources and determine the chemical composition of selected browse feed resource in Korahay Zone, Somali Regional State, was the aim of this study. Kebeles and the household heads were selected purposively in study area. The samples of fresh leaves (800 g) of selected browse species were collected to determine chemical compositions. SPSS version 20 was used for data analysis. The feed related constraints were ranked and analyzed by the ranking index. The current result indicated that, total of 22 trees, 6 shrub, 4 bush and 6 herbaceous species used as feed for livestock in dry and/or wet season were identified in the study area. DM, OM, CP, NDF, ADF, ADL and Ash of Dobera glabra, Grewia bicolor, Boscia minimfolia, Prosopis juliflora, Acacia Senegal, Unidentified (Alankhayir), Unidentified (Geed chic) were determined in current laboratory analysis. DM, OM, CP, NDF, ADF, ADL and Ash of Dobera glabra was 92.8 %, 94.28 %, 14.4 %, 42.5 %, 26.9 %, 5.22 % and 5.73 % respectively. Finally, feed quality and quantity, drought, invasive species and ecological deterioration were identified as major constraints of feed resources in study area. Due to this, intervention and further study should be conducted to tackle existing feed and feed related issues.

Advancing the Seasonal Outlook of the Wet Seasons of Florida

Abstract In this study, we introduce an ensemble approach to provide a probabilistic seasonal outlook of the length and seasonal rainfall anomaly of the wet season over Florida using the observed variations of the onset date of the season at the granularity of ∼10-km grid resolution (which is the spatial resolution of the observed rainfall data used for this work). The time series of daily precipitation at the grid resolution of NASA’s Global Precipitation Mission is randomly perturbed 1000 times to account for the uncertainty of synoptic to mesoscale variations on the diagnosis of the onset and demise date of the wet season. The strong covariability of the onset date with the seasonal length and seasonal rainfall anomaly of the wet season is then leveraged to provide the seasonal outlooks by monitoring the onset date of the wet season. This simple seasonal outlook is effective in predicting extreme tercile and even extreme pentile anomalies across Florida. We suggest that the proposed approach to the seasonal outlook of the wet season of Florida provides a viable alternative in the absence of strong external forcing like ENSO or tropical Atlantic variability that potentially limits the predictability of numerical climate models used for seasonal prediction. Significance Statement Earlier studies have shown that the seasonal prediction from the numerical climate models even at zero lead time has very limited prediction skills over the summer in Florida, which also coincides with the wettest part of the year. Florida’s wet season exhibits significant interannual variations, which exert its influence on water management decisions for subsequent drier seasons of the year. Therefore, strategies to improve this skill are highly relevant. We propose in this study that by monitoring the onset of the wet season variations, we can usefully provide a probabilistic seasonal outlook of the season over Florida. This is done by leveraging the observed linear relationships between the onset date variations with the length and the seasonal rainfall anomaly of the season. Furthermore, the outlook is provided at the spatial resolution of the observed dataset, which in this case is at 10-km grid resolution.

Population status and habitat suitability of the vulnerable common hippopotamus (Hippopotamus amphibius) in the Dhidhessa Wildlife Sanctuary, Southwestern Ethiopia

Common hippopotamuses (Hippopotamus amphibious) are among the top five herbivorous animals in Africa. Despite being listed as a vulnerable species by the International Union for Conservation of Nature, they are a common mammal in Ethiopia's protected areas, lakes, rivers, and marshes. However, there is insufficient data to evaluate status of the population and habitat compatibility across the most of the country. The aim of this research was to ascertain the population size of hippos and the suitability of its habitat in the Dhidhessa Wildlife Sanctuary (DWS) in southwest Ethiopia. The study was conducted between 2021 and 2022. To estimate the population size, the total count procedures were employed. The adaptability of each habitat for hippos was determined using the multi-ring buffer analysis in Arc GIS 10.2. A total of 231 and 133 hippos were observed during both the dry and wet seasons, respectively. Of the surveyed individuals, 62.08 % were adults, 20.88 % were under-adults, and 17 % were young. More hippos (45.1%) were observed in the savanna grassland during the rainy season. Subsequently, the hippos (50.6%) relocated to the riverine forest in the dry season. Thus, the habitats in DWS and their environs were determined to range from most suitable to unsuitable for hippos. The results showed that 58.31% of the regions were unsuitable, 18.49% were moderately suitable, and 23.18 % were highly suitable for hippos grazing. 7.95% of the research area slope was suitable, 26.32 % moderate and 65.72% not suitable and 19.8% was considered most suitable for human interference, 46.3% was severely disturbed, and 33.9% was moderately affected. Based on the current investigation, it has been determined that human interference in hippos’ habitats is significant. In order to protect the hippos’ habitats from excessive human activities and their impacts, a buffer should be created around the DWS area.

Satellite-Derived, Smartphone-Delivered Geospatial Cholera Risk Information for Vulnerable Populations.

Cholera, an acute waterborne diarrheal disease, remains a major global health challenge. Despite being curable and preventable, it can be fatal if left untreated, especially for children. Bangladesh, a cholera-endemic country with a high disease burden, experiences two peaks annually, during the dry pre-monsoon spring and the wet post-monsoon fall seasons. An early warning system for disseminating cholera risk, which has potential to reduce the disease burden, currently does not exist in Bangladesh. Such systems can raise timely awareness and allow households in rural, riverine areas like Matlab to make behavioral adjustments with water usage and around water resources to reduce contracting and transmitting cholera. Current dissemination approaches typically target local government and public health organizations; however, the vulnerable rural populations largely remain outside the information chain. Here, we develop and evaluate the accuracy of an early warning system-CholeraMap that uses high-resolution earth observations to forecast cholera risk and disseminate geocoded risk maps directly to Matlab's population via a mobile smartphone application. Instead of relying on difficult to obtain station-based environmental and hydroclimatological data, this study offers a new opportunity to use remote sensing data sets for designing and operating a disease early warning system. CholeraMap delivers monthly, color-coded geospatial maps (1km×1km spatial resolution) with household and community cholera risk information. Our results demonstrate that the satellite-derived local-scale risk model satisfactorily captured the seasonal cholera pattern for the Matlab region, and a detailed high-resolution picture of the spatial progression of at-risk areas during outbreak months.

Employing stable isotopes to reveal temporal trajectories of water travelling through the soil–plant-atmosphere continuum

The spatiotemporal patterns of water travelling through the soil–plant-atmosphere continuum (SPAC) have received much attention due to the frequency of extreme weather and water scarcity. However, the interconnections and transboundary transport of specific compartments within the hydrologic cycle are poorly understood. We portrayed the propagation paths of water isotope signals by analyzing isotopes of precipitation, soil water, and xylem water. The isotope sine curves analysis method was improved to quantify water transfer efficiency, mean transmission time from precipitation to soil (MTT1), mean transmission time from soil to trees (MTT2), mean residence time within soil (MRTSW), and mean residence time within tree xylems (MRTXY). The temporal trajectory of water traveling through SPAC was depicted, and its influencing factors and intrinsic mechanisms were explored. Our results showed that (1) water isotopes were blocked when crossing water pools (precipitation, soil water, and xylem water) and the transfer efficiency was progressively weaker (85.5 %→13.5 %). (2) The MTT1 was significantly and positively correlated with soil porosity (Spearman correlation coefficient, 0.551). Its spatiotemporal pattern (0.8–15.9d) indicated that the transport and mixing of soil water involved two modes: displacement flow and bypass flow. The MTT2 (−13.2d–4.3d) of Platycadus orientalis was in general smaller than that of Quercus variabilis (−4.7d–11.5d). (3) The MRT (35.2d–343.8d) was influenced by a combination of soil physicochemical properties, root distribution, and tree morphological traits. Our study shows that connectivity between pools is better reflected with transfer efficiency. Comparing MTT and MRT of P. orientalis and Q. variabilis, tree hydrodynamic processes were quantified, and P. orientalis was more sensitive to seasonal moisture variability. Additionally, our study improved the understanding of the “black box” within the hydrological interface of plant-soil interactions.

Thermoregulation and microhabitat use of Tachymenis peruviana (Dipsadidae) in semi-captivity conditions

Abstract We studied Tachymenis peruviana`s thermoregulatory strategy, and microhabitat use and selection in an open enclosure at 3400 m elevation during the wet season. We expected that thermal conditions at a high elevation locality would result in differences in the thermoregulatory efficiency within microhabitats through their use and selection along the day. We obtained preferred temperatures and critical thermal tolerance limits of field-captured individuals. Some individuals were kept in an open enclosure with access to four microhabitat types with retreats where to hide. We measured individuals’ field-body temperatures along with substrate and air temperatures, and recorded where the snakes were found according to microhabitat type and if they were inside or outside retreats. Meanwhile, operative temperatures were registered every hour at each offered microhabitat between 08:00 to 18:00 hours. The body and microenvironmental temperatures were highly correlated. Even though the enclosure offered appropriate thermal sources for snakes to reach their preferred temperatures, results indicate that the species met its energy requirements with a low effort in this high elevation enclosure. Almost three-quarters of the observations were recorded in retreat sites, showing a lower thermoregulatory efficiency compared to when they were captured aboveground. A comparative evaluation of the thermoregulation of the species in the field within a variety of thermal regimes experienced along its altitudinal and latitudinal range must still be carried out to better understand the species’ thermoregulatory strategies across the Andes.

The Impact of Climate Variability on Cattle Heat Stress in Vanuatu

Heat stress is a climate extreme that impacts cattle health, fertility, feed intake, production, and well-being. In Vanuatu, the beef industry is crucial to local livelihoods and the nation’s economy, thus the objective of this study was to examine the impact of heat stress on cattle health and production. This study uses the Heat Load Index (HLI) and Accumulated Heat Load (AHL) as proxies to assess the impact of heat stress on cattle in Vanuatu over a 30-year period (1994–2023), using the fifth generation of the European Centre for Medium-Range Weather Forecasts (ECMWF) atmospheric reanalysis of the global climate (ERA5) data. The analysis examines historical patterns of heat stress in cattle across Vanuatu, identifying more instances of heat stress occurring during the wet season due to characteristically elevated temperatures, humidity, and low wind speeds. Findings also suggest that El Niño events may increase the intensity and duration of heat stress events. These insights inform the development of an Early Warning System for heat stress in cattle, establishing a crucial foundation for targeted adaptation strategies aimed at enhancing the resilience and sustainability of Vanuatu’s beef industry to climate variability and change.

Ecological processes shaping highly connected bacterial communities along strong environmental gradients.

Along the river-sea continuum, microorganisms are directionally dispersed by water flow while being exposed to strong environmental gradients. To compare the two assembly mechanisms that may strongly and differently influence metacommunity dynamics, namely homogenizing dispersal and heterogeneous selection, we characterized the total (16S rRNA gene) and putatively active (16S rRNA transcript) bacterial communities in the Pearl River-South China Sea Continuum, during the wet (summer) and dry (winter) seasons using high-throughput sequencing. Moreover, well-defined sampling was conducted by including freshwater, oligohaline, mesohaline, polyhaline, and marine habitats. We found that heterogeneous selection exceeded homogenizing dispersal in both the total and active fractions of bacterial communities in two seasons. However, homogeneous selection was prevalent (the dominant except in active bacterial communities during summer), which was primarily due to the bacterial communities' tremendous diversity (associated with high rarity) and our specific sampling design. In either summer or winter seasons, homogeneous and heterogeneous selection showed higher relative importance in total and active communities, respectively, implying that the active bacteria were more responsive to environmental gradients than were the total bacteria. In summary, our findings provide insight into the assembly of bacterial communities in natural ecosystems with high spatial connectivity and environmental heterogeneity.

Assessment of Landscape‐Scale Fluxes of Carbon Dioxide and Methane in Subtropical Coastal Wetlands of South Florida

AbstractCoastal wetlands play a significant role in the storage of “blue carbon,” indicating their importance in the carbon biogeochemistry in the coastal zone and in global climate change mitigation strategies. We present airborne eddy covariance observations of CO2 and CH4 fluxes collected in southern Florida as part of the NASA BlueFlux mission during April 2022, October 2022, February 2023, and April 2023. The flux data generated from this mission consists of over 100 flight hours and more than 6,000 km of horizontal distance over coastal saline and freshwater wetlands. We find that the spatial and temporal heterogeneity in CO2 and CH4 exchange is primarily influenced by season, vegetation type, ecosystem productivity, and soil inundation. The largest CO2 uptake fluxes of more than 20 μmol m−2 s−1 were observed over mangroves during all deployments and over swamp forests during flights in April. The greatest CH4 effluxes of more than 250 nmol m−2 s−1 were measured at the end of the wet season in October 2022 over freshwater marshes and swamp shrublands. Although the combined Everglades National Park and Big Cypress National Preserve region was a net sink for carbon, CH4 emissions reduced the ecosystem carbon uptake capacity (net CO2 exchange rates) by 11%–91%. Average total net carbon exchange rates during the flight periods were −4 to −0.2 g CO2‐eq m−2 d−1. Our results highlight the importance of preserving mangrove forests and point to potential avenues of further research for greenhouse gas mitigation strategies.

Effects of Tin Mining on Water Sources in Mwerasandu Tin Mine, Ntungamo District, Uganda

Tin mining is a widespread economic activity across various regions worldwide. Understanding the consequences of such operations is crucial for sustainable water management and environmental conservation. The current study aimed at determining the concentrations tin, lead and mercury in the water sources of Nyakahiimbura Stream in Mwerasandu, and assessed the physico-chemical properties including pH, turbidity, and chemical oxygen demand (COD) of the water from the Nyamuhimbura stream, Ntungamo district. Water samples from three locations, that is; the upstream, impact area and downstream of the Nyakahiimbura water stream were collected during the dry and wet seasons of the year 2024. The samples collected were analyzed for the physico-chemical properties in the laboratory while the Inductively Coupled Plasma-Optical Emission Spectrometry (ICP – OES) was used to determine the concentration of heavy metals in the water samples. The pH, COD values obtained were within the acceptable effluent standards while the turbidity values at the upstream and downstream of the dry season and downstream during the wet season were above the acceptable effluent Standards. The tin concentration was high in the dry season (0.09mg/L) as compared to concentration (0.118mg/L) in the wet season. Lead concentration was the same (0.015mg/L) in both seasons. The concentrations of the heavy metals showed some variations in both dry and wet seasons in the upstream, impacted area and the downstream of the study area as compared to the values of the effluent standards. The study recommends that alternative sources of water for domestic use should be sought of. Also, the government officials especially from the Ministry of Health should carry out awareness campaigns to members of the community about the health risks associated with the uptake of the contaminated waters for domestic purposes. Constructed wetlands should be in place around the mining sites to act as filters for the dangerous metals before the water enters the surrounding environment.

Analysis of groundwater and surface water quality using modelled water index and multivariate statistics in Kampala and Mbarara Districts, Uganda

The demand for domestic, public and industrial use of water increases with population growth. However, activities from humans and natural environment have resulted into decline in water quality. The aim of this study was to evaluate the quality of groundwater and surface water collected from Kampala and Mbarara districts of Uganda using water quality index and multivariate statistics. A total of 10 physicochemical parameters (pH, water temperature, chloride, sulphate, nitrate, electrical conductivity, total dissolved solids, total suspended solids, total solids, and phosphate) were measured monthly to evaluate the quality of water in the study districts. Results showed that sulphate, electrical conductivity and total dissolved solids were observed with significantly high values in surface water than the groundwater for both seasons. Among all the parameters measured, electrical conductivity was observed with the highest value (2129.67 ± 1.41 µS/cm) while nitrate concentration (0.57 ± 0.02 mg/L) was observed with the lowest during the wet season in surface water. In addition, the mean values of nitrate, electrical conductivity, total dissolved solids and sulphate detected in the groundwater and surface water were within the recommended limits, while phosphate and chloride were observed with mean concentrations above the regulatory limits in 50% of the samples. The correlation analysis revealed strong and positive association between electrical conductivity and total dissolved solids in groundwater and surface water for both seasons. Also, the chemical make-up of groundwater and surface water within the study districts revealed that the determination of water quality rests on two major indices (conductivity and anthropogenic-pollutants) based on the factor analysis. The two indices accounted for 0.619% in groundwater and over 0.70% in surface water, indicating more pollution in surface water. Moreover, the water quality index (WQI) values obtained ranged from 14.81 to 115.73 in dry season and 7.77 to 108.24 during the wet season. According to WQI classification, 42% of the samples collected fell within the “excellent” and “good” categories while others fell within “poor” and “unfit” categories (58%) during the dry season. Based on these findings, appropriate treatment methods, proper sanitation and waste management should be implemented in locations with critical water conditions. Also, frequent monitoring of groundwater and surface water quality by environmental protection agency is highly recommended.

New multivariate models for the estimation of earth’s albedo and its variation with meteorological parameters over Kano, Nigeria

The study of what happens to sunlight as it goes through the atmosphere is vital to many fields of science because over time, reflection, scattering, and absorption in the atmosphere have changed the amount of solar radiation that reaches the Earth's surface. This study examined the variation in albedo over Kano, situated in the Sahelian climatic zone of Nigeria. The study's data, which covered the years 1984–2022, totaled thirty-nine, was obtained from the National Aeronautics and Space Administration (NASA). Utilizing monthly average daily measured meteorological data on global solar radiation, wind speed, mean temperature, surface pressure, and relative humidity, eleven models of three categories based on two, three, and four variable regression models were developed. Five validation indicators were used to verify the regression models: the t-test, coefficient of determination (R2), mean percentage error (MPE), root mean square error (RMSE), and mean bias error (MBE). The developed models that were considered most appropriate for estimating surface albedo were ranked; the three-variable regression model ALB7, which included the wind speed, relative humidity, and mean temperature, outperformed the previously employed generalized method from literature in estimating surface albedo over Kano. The variation of measured albedo with meteorological parameters depicts a direct relationship for clearness index and wind speed; an inverse relationship was observed for surface pressure. Mean temperature and surface pressure exhibit an inverse relationship during the wet season and vice versa for the dry season.

Effects of multiple mammalian herbivores and climate on grassland-shrubland transitions in the Chihuahuan Desert.

The replacement of grasses by shrubs or bare ground (xerification) is a primary form of landscape change in drylands globally with consequences for ecosystem services. The potential for wild herbivores to trigger or reinforce shrubland states may be underappreciated, however, and comparative analyses across herbivore taxa are sparse. We sought to clarify the relative effects of domestic cattle, native rodents, native lagomorphs, and exotic African oryx (Oryx gazella) on a Chihuahuan Desert grassland undergoing shrub encroachment. We then asked whether drought periods, wet season precipitation, or interspecific grass-shrub competition modified herbivore effects to alter plant cover, species diversity, or community composition. We established a long-term experiment with hierarchical herbivore exclosure treatments and surveyed plant foliar cover over 25 years. Cover of honey mesquite (Prosopis glandulosa) proliferated, responding primarily to climate, and was unaffected by herbivore treatments. Surprisingly, cattle and African oryx exclusion had only marginal effects on perennial grass cover at their current densities. Native lagomorphs interacted with climate to limit perennial grass cover during wet periods. Native rodents strongly decreased plant diversity, decreased evenness, and altered community composition. Overall, we found no evidence of mammalian herbivores facilitating or inhibiting shrub encroachment, but native small mammals interacting with climate drove dynamics of herbaceous plant communities. Ongoing monitoring will determine whether increased perennial grass cover from exclusion of native lagomorphs and rodents slows the transition to a dense shrubland.

First Insights into the Fecal Metabolome of Healthy, Free-Roaming Giraffes (Giraffa camelopardalis): An Untargeted GCxGC/TOF-MS Metabolomics Study

Background/Objectives: This study provides the first insights to the fecal metabolome of the giraffe (Giraffa camelopardalis). By using untargeted metabolomics via gas chromatography time-of-flight mass spectrometry (GCxGC/TOF-MS), this study primarily aims to provide results of the impact that external stimuli, such as supplemental feeding (SF) practices, seasonal variation and sex, might have on the fecal metabolome composition of healthy, free-roaming giraffes. Methods: Untargeted GCxGC/TOF-MS analysis was applied to the feces collected from thirteen giraffes (six males and seven females) from six different locations within the central Free State Province of South Africa over a period of two years. Statistical analysis of the generated data was used to identify the metabolites that were significantly different between the giraffes located in environments that provided SF and others where the giraffes only fed on the natural available vegetation. The same metabolomics analysis was used to investigate metabolite concentrations that were significantly different between the wet and dry seasons for a single giraffe male provided with SF over the two-year period, as well as for age and sex differences. Results: A total of 2042 features were detected from 26 giraffe fecal samples. Clear variations between fecal metabolome profiles were confirmed, with higher levels of amino acid-related and carbohydrate-related metabolites for giraffes receiving SF. In addition, a separation between the obtained profiles of samples collected from a single adult male giraffe during the wet and dry seasons was identified. Differences, such as higher levels of carbohydrate-related metabolites and organic compounds during the wet season were noted. Distinct variations in profiles were also identified for the metabolites from fecal samples collected from the six males and seven females, with higher concentrations in carbohydrate-related metabolites and alkanes for female giraffes comparatively. Conclusions: This is the first study to investigate the composition of the fecal metabolome of free-roaming giraffes, as well as the effects that external factors, such as environmental exposures, feeding practices, seasonal variations, age and sex, have on it. This novel use of fecal metabolomics assists in developing non-invasive techniques to determine giraffe populations’ health that do not require additional stressors such as capture, restraint and blood collection. Ultimately, such non-invasive advances are beneficial towards the conservation of wildlife species on a larger scale.

Long-term rainfall and water table influence on groundwater nutrient dynamics from an oil palm plantation

ABSTRACT Conservation of groundwater quality is of paramount importance for sustainable agricultural management. Hydrological factors such as rainfall patterns and water table (WT) management, including drainage practices, play a crucial role in groundwater recharge. This in turn has a significant impact on WT fluctuations, nutrient losses in the soil, and the leaching of fertilizers into groundwater which leads to groundwater pollution. Consequently, this study evaluates the long-term influence of seasonal rainfall and WT fluctuations on groundwater nutrient dynamics in tropical peatlands from an oil palm plantation (OPP). Linear regression analyses and Pearson correlation matrices were adopted to evaluate the relationships between seasonal rainfall, WT, and groundwater chemical parameters. The results showed that there was a significant increase in mean pH, NO3 −, Na+, Ca2+, and PO4 3- values during the wet season compared to the dry season which could be attributed to the leaching of nutrients into groundwater due to rainfall, nutrient runoff from drainage systems and increased nitrification rate. A significant positive correlation (p < 0.01) was found between groundwater pH and NO3 − during the wet season, suggesting that increased groundwater pH due to heavy rainfall directly affects the nitrification process. It was also observed that low WT promotes denitrification in shallow groundwater, with this effect being more significant (p < 0.05) during the dry season. This was reflected in the higher correlation values between the WT fluctuations and the NH4 + concentrations in the groundwater. This research represents the first study to explore the long-term impacts of rainfall and WT fluctuations on groundwater quality in tropical peatlands. The insights gained from this study offer valuable guidance for WT management strategies aimed at conserving groundwater quality in such environments, ultimately contributing to sustainable agricultural practices.

Assessing microplastic abundances in freshwater fishes in a subtropical African reservoir

Microplastics are emerging pollutants of global concern, and their presence in the aquatic environment poses a serious risk for aquatic biota. While many studies have been conducted on the presence of microplastics in marine habitats, little research has been done in freshwater African reservoirs on microplastic pollution and their impacts on fish within the subtropical regions. To bridge this gap, the current study investigated microplastic abundances and distribution in freshwater fish within Nandoni reservoir, South Africa, across two seasons (i.e., hot–wet, cool–dry). Fish were randomly sampled using seine and gill nets from seven sites within the reservoir. In the laboratory, fish were then sorted according to taxa before dissecting them to remove the gills and the gastrointestinal tract (GIT). The organs were digested using hot hydrochloric acid and hydrogen peroxide, and the microplastics were classified according to their colours and shapes. Among the 94 fishes (i.e., 8 species) examined, microplastics were detected in 86.6% of the eight species caught. Microplastics were dominant in the gills and GIT during the cool–dry and hot–wet seasons, respectively. High microplastic abundances were found in the gills of Micropterus salmoides and the GIT of Coptodon rendalli, where fibres and the transparent colour were the most dominant. The results further showed high microplastic abundances in benthopelagic feeders highlighting that habitat influences fish consumption of microplastics whether directly or indirectly. Significant differences were observed in the feeding zone and season for all microplastic types. Microplastic sources in the reservoirs could be due to anthropogenic activities such as illegal dumping, fishing, and agriculture. Thus, there is a need for further investigation into the relation of fish weight, fish sex and body in relation to microplastic pollution. The highlighted ecological factors should be taken into consideration for future research and management actions aimed at mitigating and protecting the negative impacts of microplastic pollution on environmental and human health.

Metabolomic Fingerprints: Seasonal and Farm-Specific Differences in Heterotrigona itama Bee Bread

Stingless bees’ products such as honey and bee bread are beneficial to human health. However, the metabolite composition within the products may differ according to spatial and temporal factors. This study aims to investigate the impact of spatial and temporal factors on the significant metabolite composition present in Heterotrigona itama bee bread collected from different seasons and types of bee farms. Thus, tandem mass spectrometry (LCMS/MS) based metabolomics analysis was used to achieve the said goal, focusing on H. itama bee bread samples, followed by multivariate analysis using the MetaboAnalyst platform. Our findings revealed significant metabolites that set bee bread samples apart. In terms of temporal factors, the analysis highlights specific metabolites exclusive to the wet season, such as flavones and flavonoids. However, in contrast, during the wet season, there are no significant metabolites in herbal farm samples. The results also underscore the significance of phenolic compounds in wet season samples and as vital metabolites distinguishing the groups. This study highlights a total of 24 annotated significant metabolites identified in different bee bread samples, as well as their capacity to differentiate between seasons and bee farms. Notably, these results suggest a wide variety of potential plant families as a source of bee bread. These findings shed light on the impact of seasons and diverse plant families contributing to bee bread composition, which may impact the growing meliponiculture industry greatly.

Exposure to aflatoxins and ochratoxin A from the consumption of selected staples and fresh cow milk in the wet and dry seasons in Ghana

Across sub-Saharan Africa, the heavy reliance on mycotoxin-susceptible staple foods means that populations in the region are particularly vulnerable to chronic mycotoxin exposure. This study assessed the exposure risk to ochratoxin A (OTA) and aflatoxins (AFs) from 18 samples of selected staple foods (maize, millet, groundnut) and 56 fresh cow milk samples collected from across Ghana. The foods were sampled simultaneously to maximise comparability, and at two timepoints in March/April (during the dry season) and July/August (during the rainy season) to assess the effects of duration of storage and seasonal conditions on the mycotoxin levels as measured by high-performance liquid chromatography. The margin of exposure (MOE) approach was used to assess the exposure risk from consumption of the sampled foods. Each of the sampled staples was contaminated with OTA (0.19–3.11 ng/g) and at least one AF (0.75–13.05 ng/g B1, ND-12.12 ng/g B2, 0.1–9.95 ng/g G1, ND-16.78 ng/g G2). Up to 67% had contamination above European Food Safety Authority (EFSA) maximum limits, and 50% were above Ghana Standards Authority (GSA) limits. The fresh cow milk samples were contaminated with AFM1 in the range of 0.05–1.49 ng/g, with 95% above EFSA limits and 36% above GSA limits. Aflatoxin contamination in the staples was high, particularly in July/August when the wet conditions may have adversely impacted the handling and storage of farm produce. Variation in AFM1 between the two sampling periods mirrored total aflatoxin in the staples, suggesting that even if dairy cattle were grazing in open pasture and not being rationed on stored feed, then there was a high environmental presence of aflatoxigenic fungi. The MOE estimates were ≤533.09, far below the safe cut-off of 10,000 for suspected carcinogenic compounds. The high mycotoxin levels indicate a priority risk to child nutrition which relies heavily on cereal mixes based on one or all the three sampled staples. The data from this study underscore the urgent need for interventions to better appreciate and address mycotoxin exposure for enhanced food security and public health in Ghana and across sub-Saharan Africa.

Spatiotemporal Distribution of nirS-Type Denitrifiers in Cascade Reservoir Sediments of the Qinghai Plateau

Compared to single damming, the impact of cascade damming on nitrogen-related microorganisms in river ecosystems exhibits greater complexity. However, there is still a lack of research on the response of denitrifiers to the construction of cascade reservoirs. A study was conducted on 10 cascade reservoirs in the upper reaches of the Yellow River to investigate the impact of cascade reservoir construction on nirS-type denitrifying bacteria in sediments. Sediment samples were collected in May (dry season) and August (wet season) of 2023. The spatiotemporal characteristics of the nirS-type denitrifying bacterial community and gene abundance were analyzed using Illumina high-throughput sequencing and real-time fluorescence quantification PCR (qPCR). Redundancy analysis (RDA) and variation partitioning (VP) were utilized to assess the impact of environmental factors on these communities. The results showed the following: (1) Proteobacteria was the predominant phylum of nirS-type denitrifying bacteria in cascade reservoir sediments. At the genus level, unclassified Proteobacteria (69.51–95.64%) showed the highest relative abundance, followed by Paracoccus, Rhodanobacter, and Pseudomonas, indicating that unclassified Proteobacteria may dominate denitrification in these reservoir sediments. (2) The α and β diversity indices of nirS-type denitrifying bacteria were higher in the dry season than in the wet season, and also higher in young reservoirs compared to old reservoirs (p &lt; 0.05). (3) Temporally, the abundance of the nirS gene was significantly higher in the wet season (12.71 × 107 copies/g dry sediment) compared to the dry season (66.35 × 105 copies/g dry sediment). Spatially, the abundance of the nirS gene was higher in the central region, while relatively lower at both ends. (4) RDA and VP analysis indicated that the community structure and abundance of nirS-type denitrifying bacteria were significantly influenced by the total nitrogen in sediments (19.31%) and water temperature (14.13%). Spearman correlation analysis showed that organic carbon significantly affected the diversity of nirS-type denitrifying bacteria (p &lt; 0.05). The results contribute to a better understanding of the nitrogen-related microbial community in cascade reservoir sediments of the Yellow River, providing a scientific basis for reservoir management.

Risk assessment and seasonal variation of atmospheric ammonia in Ondo State, Nigeria

The environment is impacted by atmospheric ammonia (NH3) in a number of ways, including the global nitrogen cycle, ecology, and the production of secondary particles. Our findings present an unparalleled depiction of the temporal and geographical properties of atmospheric NH3 in and around this megacity, based on long-term, continuous measurements of NH3 at various locations in Ondo State. The increase in atmospheric ammonia during this anthropogenic era is believed to pose a significant threat to humanity, with scientists linking it to a rise in global warming and climate change. KP-826 multiple gas detector was used to investigate ammonia gas in five locations within Ondo state and its correlation with meteorological parameters was examined in this study. The selection of Dumpsite, Cattle rearing farm and Poultry farm was purposeful because of their involvement in the production of ammonia gas. The mean concentration of NH3 (ppm) during wet season was 3.87 ± 1.60 and for dry season was 5.87 ± 1.60. The mean temperature (°C) in wet conditions is 32.51 ± 1.27, which is a little lower than the mean (33.51 ± 1.25) in dry conditions. The mean wind speed (in m/s) during wet conditions is 1.21 ± 0.32, which is greater than the mean wind speed (in m/s) during dry conditions of 1.11 ± 0.32. The mean value of humidity for wet situations is 72.08 ± 2.31, which is a little lower than the mean value for dry conditions, which is 76.07 ± 2.31. This work evaluated the potential health risks associated with NH3. The total hazard quotient (THQ) for adult was 1.30 × 10–6 for children 1.50 × 10–6. The children's HQ ranged from 2.41 to 4.15. The adult's ranged from 8.70 to 15.13. However, it was discovered that the health risk posed by breathing in atmospheric NH3 was far higher than the USEPA limits, where HQ > 1.