Spatial Variation Research Articles

Dynamicity of ecosystem service value driven by land use/land cover alteration in Vadodara City, India

The ecosystem is considered the fundamental unit of ecology which plays a crucial role in providing a range of essential services to individuals. These services include the provision of food and shelter, as well as the regulation of climate and environment, either directly or indirectly. However, the emergence of urban industrial cities has witnessed the uncontrolled exploitation of resources, the decline of biodiversity, unprecedented population growth and climate change. Consequently, these factors contribute to environmental crises as ecosystem services increase in urban areas, where higher ESV values adversely affect the environment. Considering this, the current study examines the relationship between land use change and the status of ecosystem services in Vadodara City, India. The ecosystem service value was calculated using the methodology proposed by (Costanza et al. in Ecol Econ 25:3–15, 1997;Costanza et al. in Glob Environ Chang 26:152–158, 2014;), while the contribution of Land Use/Land Cover (LULC) was determined using the Maximum Likelihood Classification. The findings highlighted that LULCs are critical drivers for the loss of ecosystem services. During 2001–2021, it was found that built-up and water bodies increased by 24.48% and 0.21%, respectively, while vegetation, agricultural and barren land decreased by 1.11%, 25.61% and 0.19% respectively. The valuation of ecosystem services in 2001 observed $3,517,118 and $125,607,186 using the corresponding coefficients of (Costanza et al. in Ecol Econ 25:3–15, 1997;Costanza et al. in Glob Environ Chang 26:152–158, 2014;), while in 2021, their cumulative value slightly increased to $3,629,024 based on the 1997 coefficient and $131,537,398 based on the 2014 coefficient. Furthermore, the study analyses the response of ecosystem service values to land use alterations and the elasticity value at the zonal level to gain insight into spatial variation.

Spatially resolved spectroscopic analysis of Lyα haloes

The extended Lyα haloes (LAHs) have been found to be prevalent around high-redshift star-forming galaxies. However, the origin of the LAHs is still a subject of debate. The spatially resolved analysis of Lyα profiles provides an important diagnostic. We analyse the average spatial extent and spectral variation of the circumgalactic LAHs by stacking a sample of 155 Lyα emitters (LAEs) at redshifts of 3 < z < 4 in the MUSE Extremely Deep Field. Our analysis reveals that, with respect to the Lyα line of the target LAE, the peak of the Lyα line at large distances becomes increasingly more blueshifted up to a projected distance of 60 kpc (≈3× virial radius), with a velocity offset of ≈250 km/s. This trend is evident in both the mean and median stacks, suggesting that it is a general property of our LAE sample, which typically has a Lyα luminosity of ≈1041.1 erg s−1. However, due to the absence of systemic redshift data, it remains unclear whether the Lyα line peak at large projected distances is less redshifted compared to the inner regions or truly blueshifted with respect to the systemic velocity. We explore various scenarios to explain the large-scale kinematics of the Lyα line.

A literature review: rainfall thresholds as flash flood monitoring for an early warning system

ABSTRACT Flash floods, increasingly common and impactful, can be better managed through effective early warning systems. This study reviews methods for determining rainfall thresholds using empirical, hydrological, and machine learning approaches. Empirical methods, based on historical data, identify patterns between rainfall and floods but struggle with spatial and temporal variations. Hydrological methods, which consider watershed characteristics, offer greater accuracy but require detailed data. Machine learning, with its capacity for real-time, adaptive analysis of big data, shows promise for improving predictions. Integrating these approaches can enhance early warning systems, making them more effective in the face of climate change and significantly reducing the impact of flash floods.

Effects of Climate Change on Temperature Sensitivity of Vegetation Growth in Huang-Huai-Hai Plain: Spatial–Temporal Dynamics and Ecological Adaptability

This paper explores the optimal temperature change in normalized difference vegetation index (NDVI) growth in the Huang-Huai-Hai Plain under the background of climate change, aiming to better cope with the impact of global warming on vegetation growth. The temporal and spatial variation characteristics of the NDVI and temperature factors were analyzed by using the NDVI, average temperature (Tavg), maximum temperature (Tmax) and minimum temperature (Tmin) datasets from 1982 to 2020. Through the Buishand U test and sliding slope detection, 1998 was determined to be a year of abrupt climate change. Furthermore, SHAP important feature analysis, a generalized additive model, correlation analysis, and other methods were used to identify the trend in the optimum temperature of vegetation growth before and after climate change. The results showed that (1) from 1982 to 2020, Tavg, Tmax, Tmin, and the NDVI in Huang-Huai-Hai Plain showed a significant upward trend. At the same time, the spatial distribution of these indicators shows the distribution characteristics of high in the south and low in the north. (2) The NDVI was positively correlated with Tavg, Tmax, and Tmin, and the correlation with Tmin was most significant. (3) The most suitable Tavg, Tmax, and Tmin intervals for vegetation growth were 20~30 °C, 25~35 °C, and 16~25 °C, respectively. (4) The optimum temperature range of vegetation growth was expanded after climate change, and the change rates of the Tavg and Tmax lower limits reached 24% and 25%, respectively, under the best condition of vegetation growth. (5) After abrupt climate change, the temperature suitable for vegetation growth increased significantly in the northern part of the plain but decreased slightly in the southern part.

Geochemical Dynamics and Evolutionary Implications of Sediments at the Xingu–Amazon Rivers’ Confluence: Proxies for Mixing, Mobility and Weathering

This study investigates the geochemical characteristics and evolutionary implications of sediments at the confluence of the Xingu and Amazon Rivers. The main objective is to understand sediment mixing, mobility, and weathering processes through geochemical proxies. Samples were collected from various sections of the lower Xingu River, focusing on its interaction with the Amazon River. Analytical techniques such as X-ray diffraction (XRD), X-ray fluorescence (XRF), and inductively coupled plasma mass spectrometry (ICP-MS) were employed to analyze major and trace elements. The results reveal significant spatial variations in mineralogical and textural patterns, with sediments forming distinct groupings based on their location. The data suggest that the lower Xingu River is strongly influenced by sediment inputs from the Amazon River, particularly affecting sediment composition and chemical weathering processes. This research highlights the critical interactions between river systems and their implications for the evolution of the Amazon basin, especially regarding sediment contributions from various geological sources. Even though the Xingu River drains cratonic regions at higher elevations, the geochemistry of the bottom sediments confirms that the bedload is derived from heterogeneous sources with primarily intermediate igneous compositions and has undergone substantial recycling during river transport.

Subgrade performance assessment for rigid runway using long-term pavement performance database

Maintaining desired subgrade performance is an effective way to reduce runway pavement deterioration. Due to lack of extensive field test data, life-cycle performance of runway subgrade has not been fully understood. In order to quantitatively estimate subgrade condition, a novel method of evaluating subgrade performance was developed and validated using the 726 sets of Heavy Weight Deflectometer (HWD) test data of ten runway sections. Statistical analysis demonstrates that the structural behaviour of rigid runway subgrade follows normal distribution in different service stages and can be efficiently evaluated by the subgrade performance index (ψ). The results of factor analysis show that Accumulated Air Traffic Volume (ATV) during service life is the major cause of spatial variations in subgrade condition. In the designed service period of runway, it validates that sea-reclaimed subgrade results in faster degradation in the initial stage of service life while thicker pavement exhibits better capability in protecting the subgrade soil in long-term view. Besides, the differences in applied loads and pavement thickness give rise to the subgrade performance variation in longitudinal direction. Meanwhile, the comparison between the main and the less trafficked test lines in transversal direction reveals that the aircraft impacts play a positive role in resisting the natural fatigue process. By the suggested method, subgrade performance of HWD test points can be categorized into 4 levels from “Excellent”, “Good”, “Fair” to “Poor” based on ψ value. It is helpful for airport agency to make scientific decisions on Maintenance and Rehabilitation (M&R) treatment by calculating the effective area of envelope (β) using the ratio of subgrade performance (η).

Interrogating the environmental and social correlates of health risk behaviours in West Africa

Abstract Background Despite the high incidences of health risk behaviors (HRBs) in sub-Saharan Africa, studies on the contextual determinants of HRBs across countries are generally lacking, concentrated on isolated countries and often focus solely on specific health behaviors. Thus, this study investigated the environmental and social correlates of HRBs in West Africa. Methods Data was from post-2015 Demographic and Health Surveys in three West African countries of Benin, Mali and Nigeria. A composite outcome variable of health risk behaviors (HRBs) was derived from variables of tobacco smoking, intimate partner violence, overweight/obesity and risky sexual behaviors. The contextual variables were normalized difference vegetation index, precipitation, maximum and minimum temperatures, region of residence and population Density. Data analysis involved descriptive statistics, chi square test, geographical mapping, and multilevel logistic regression. Results The engagement in HRBs varied from 42.65% in Nigeria to 42.88% in Benin and 51.06% in Mali as there are spatial variations in the engagement in HRBs within different regions of these countries. There also existed significant variations in HRBs regarding age, education, employment status, wealth index, household size, place of residence, and region of residence in the three countries. In the contextual models of environmental and social factors, population density significantly increased odds of HRBs in the three countries, maximum temperature significantly increased odds of HRBs in Benin and Mali, while precipitation significantly increased odds of HRBs in Nigeria and Mali. Other factors which significantly increased odds of HRBs across the three countries were increase in age, wealth index, households with 9+ persons, and regions of residence. Conclusions These findings suggest that among other things, changes in lifestyles regarding the different HRBs should be emphasized in specific contextual situations Key messages • There are variations in engagement in health risk behaviours across the countries. • Cliamte variables influence engagement in health risk behaviours.

Optimizing surface water quality parameters in monitoring networks in a developing sub-tropical region with high anthropogenic pressure (São Paulo State Brazil).

Efficient water quality monitoring is a central aspect of water resources management, especially in developing countries, where water quality is under high anthropogenic pressure and resources for monitoring are usually limited. Here, we evaluated an alternative to optimize water quality parameters (WQPs) in the water quality monitoring network (WQMN) of the most populous state in Brazil (São Paulo State). We focused on the monitoring goal of identifying water quality temporal trends, selecting WQPs with high statistical explanatory power and those that were particularly sensitive to natural and anthropogenic perturbations. We considered 12 initial WQPs (dissolved copper, total zinc, total lead, total chromium, total mercury, total nickel, total cadmium, total iron, total manganese, total aluminum, total copper, and surfactant) with data from 2004 to 2018 for 56 monitoring sites distributed across four major watersheds with contrasting land uses in the state. We performed principal component analysis, followed by objective criteria to refine WQPs recommendation for the WQMN. Our results indicated the opportunity of reducing at least one parameter from the initial set of WQPs in all watersheds. Total iron, total manganese, and total aluminum were the most relevant initial WQPs, since their maintenance in monitoring were indicated in all the analyzed cases. Natural watershed conditions (e.g., geomorphology and water geochemistry) potentially governed their concentrations in surface water. On the other hand, total mercury, total chromium, and dissolved copper had the maintenance indicated in only one watershed, especially due to concentrations consistently below the respective limits of quantification (LoQs). Future investigations can complement our recommendations for these parameters, since changes in LoQs could throw another light on water quality spatial and temporal variations and the need for reference areas for assessing baseline conditions can also be relevant. Moreover, we argue that depending on the monitoring goals of the WQMN, additional sampling of biota and sediments could be useful as many of the studied WQPs' bioconcentrate. Our results illustrated an alternative approach towards adaptive monitoring in São Paulo state in accordance with the intended monitoring goal (i.e., water quality temporal trends), converging with the more flexible monitoring adopted in well-structured networks worldwide. While we did not cover other monitoring goals in our study (as the control of illegal discharge of effluents or industrial spills, for example), we expect our methodology can contribute to establishing technical guidelines for reviewing the existing WQMNs in Brazil and other developing countries with similar challenges.

Hydrogeochemical Processes in Basement Areas Using Principal Component in Burkina Faso (West African Sahel)

The basement aquifers in Burkina Faso are increasingly exposed to groundwater pollution, largely due to socio-economic activities and climatic fluctuations, particularly the reduction in rainfall. This pollution makes the management and understanding of these aquifers particularly complex. To elucidate the processes controlling this contamination, a methodological approach combining principal component analysis (PCA) and multivariate statistical techniques was adopted. The study analyzed sixteen physicochemical parameters from 58 water samples. The primary objective of this research is to assess groundwater quality and deepen the understanding of the key factors influencing the spatial variation of their chemical composition. The results obtained will contribute to better planning of preservation and sustainable management measures for water resources in Burkina Faso. The results show that three principal components explain 72% of the variance, identifying anthropogenic inputs, with two components affected by mineralization and one by pollution. The study reveals that the groundwater is aggressive and highly corrosive, with calcite saturation. Water-rock interactions appear to be the main mechanisms controlling the hydrochemistry of groundwater, with increasing concentrations of cations and anions as the water travels through percolation pathways. PCA also revealed that the residence time of the water and leaching due to human activities significantly influence water quality, primarily through mineralization processes. These results suggest that rock weathering, coupled with reduced rainfall, constitutes a major vulnerability for aquifer recharge.

Influence of Spatially Varied Soil Property on Train-Induced Soil-to-Column Vibration Transmission

The proximity of residential areas to traffic corridors has raised concerns among researchers regarding train-induced vibrations. Experimental studies have consistently shown variations in train-induced vibrations, which can be attributed to uncertainties and randomness in both the vibration source and propagation path. This study aims to investigate the influence factors and quantify their contributions to train-induced vibration variations through a comprehensive field measurement campaign and numerical simulations using random finite element models. During the field measurements, vibrations were recorded at the ground surface and the column base for a total of 53 passbys of the same type of metro train on parallel rail lines. Variations in train-induced vibrations caused by the source-to-receiver distance and spatially varied soil properties were analyzed and compared. Specifically, the investigation focused on the spatial variation of soil properties including elastic modulus, density and damping ratio in the topsoil and the second layer of clay, while simultaneously considering the influence of spatial variations of all three soil properties on the transmission of train-induced vibrations from the surface soil to the structural columns. Understanding these variations is crucial for the probabilistic assessment of building serviceability during train passbys. The findings of this research provide valuable insights for probabilistic prediction and evaluation of building vibration comfort.

Geographical variation in prostate cancer testing explained by socio-economic position in Stockholm

Abstract Background Prostate cancer screening using prostate-specific antigen (PSA) testing is controversial but remains prevalent in many countries. Despite its prevalence there is little information in Sweden or globally on the spatial heterogeneity in PSA testing. This study aims to describe the spatio-temporal variation in PSA testing in the Stockholm region specifically at the municipality and small area level. Additionally, it aims to quantify the extent to which socio-economic position (SEP) indicators such as education, income, and country of birth explain the observed variation in PSA testing. Methods A retrospective population-based register study was conducted, encompassing men aged 40 years and older residing in the Stockholm region from 2007 to 2016. Utilizing spatial smoothing techniques, we calculated the age-standardised proportion of men undergoing PSA testing prior to any prostate cancer diagnosis within each area for every calendar year. Furthermore, we used Bayesian logistic regression models with spatial random effects to estimate the individual-level association between PSA testing and socio-economic position. The proportion of variance in PSA testing explained by various measures of SEP was also estimated at both the municipality and small area levels. Results Significant geographical disparities in PSA testing were observed across small areas within Stockholm. The proportion of variance explained in PSA testing at the small area level was highest for income (32.6%), followed by education (9.7%) and country of birth (7.4%). Incorporating all SEP measures led to a higher proportion of explained variance at the small area level (41.6%) compared to the municipality level (24.8%). Conclusions PSA testing was significantly associated with various socio-economic indicators and some of the spatial variation could be explained by SEP. It would be useful to ascertain whether similar patterns are observed in other regions or countries. Key messages • The findings suggested widespread and consistent opportunistic prostate cancer screening practices within the Stockholm region, raising concerns regarding potential overdiagnosis and overtreatment. • The socio-economic differences in prostate cancer screening could partially explain the differences in cancer incidence and mortality.

Tunable topological phases in nanographene-based spin-1/2 alternating-exchange Heisenberg chains.

Unlocking the potential of topological order in many-body spin systems has been a key goal in quantum materials research. Despite extensive efforts, the quest for a versatile platform enabling site-selective spin manipulation, essential for tuning and probing diverse topological phases, has persisted. Here we utilize on-surface synthesis to construct spin-1/2 alternating-exchange Heisenberg chains by covalently linking Clar's goblets-nanographenes each hosting two antiferromagnetically coupled spins. Using scanning tunnelling microscopy, we exert atomic-scale control over chain lengths, parities and exchange-coupling terminations, and probe their magnetic response via inelastic tunnelling spectroscopy. Our investigation confirms the gapped nature of bulk excitations in the chains, known as triplons. Their dispersion relation is extracted from the spatial variation of tunnelling spectral amplitudes. Depending on the parity and termination of chains, we observe varying numbers of in-gap spin-1/2 edge excitations, reflecting the degeneracy of distinct topological ground states in the thermodynamic limit. By monitoring interactions between these edge spins, we identify the exponential decay of spin correlations. Our findings present a phase-controlled many-body platform, opening avenues toward spin-based quantum devices.

Socioeconomic deprivation and tuberculosis in Germany: a longitudinal spatial analysis (2001–2022)

Abstract Background Socioeconomic conditions may affect tuberculosis (TB) dynamics. We analyzed the relation between area-level socioeconomic deprivation and TB incidence in Germany between 2001-2022. Methods Using nationally representative data at the level of 400 German districts, we fitted generalized linear mixed models to assess the effect of socioeconomic deprivation on TB incidence controlling for age, sex, share of non-nationals population, share of refugees, geographic effects, location and time. We estimated crude and adjusted risk ratios (RR) and corresponding 95% Confidence Intervals (95%-CI) for socioeconomic deprivation quintiles (Q1-Q5), ranging from least (Q1) to most deprived (Q5) districts. Results Preliminary findings show that crude TB incidence risk was 7% higher (RR = 1.07, 95%-CI=1.04-1.09) in least (Q1) compared to most deprived areas (Q5). Districts with medium-low (Q2), medium (Q3), and medium-high (Q4) socioeconomic deprivation showed 1% higher (1.01, 0.98-1.03), 4% lower (0.96, 0.94-0.99) and 3% lower (0.97 0.94-1.00) risk, respectively, compared to the most deprived districts (Q5). Fully adjusted incidence risk was 6% lower for Q1 compared to Q5 (0.94, 0.86-1.02), while districts classified in quintiles Q2-Q4 showed 8% (0.92, 0.86-0.99), 6% (0.94, 0.88-1.01) and 3% (0.97, 0.92-1.02) lower risk compared to Q5, respectively. Conclusions The adjusted effect of area-level socioeconomic deprivation on the risk of TB incidence has been low in Germany. Not considering the assumed confounders leads to over-estimation of the association between area-level SES and TB. Future studies should explore further area-level or individual factors in order to better understand the spatial variation of TB incidence in Germany. Key messages • Area-level socioeconomic deprivation has a low effect on the risk of TB incidence across German districts. • Further research is needed in order to better understand the spatial variation of TB incidence in Germany.

Diffusion kurtosis imaging, MAP-MRI and NODDI can selectively track gray matter myelin density in the primate cerebral cortex

Abstract Diffusion magnetic resonance imaging (dMRI) has been widely used to model the trajectory of myelinated fiber bundles in the white matter. Increasingly, it is also used to evaluate the microstructure of the cerebral cortex gray matter. For example, in diffusion tensor imaging (DTI) of the cortex, fractional anisotropy (FA) correlates strongly with the anisotropy of cellular anatomy, while radial diffusivity (RD) tracks the anisotropy of myelinated fibers. However, no DTI parameter shows specificity to gray matter myelin density. Here we show that three higher order diffusion parameters - the mean diffusion kurtosis (MK), the Neurite Density Index (NDI) from NODDI, and the Non-Gaussian (NG) parameter from MAP-MRI— each track the laminar and regional myelin density of the primate cerebral cortex in fine detail. We carried out ultra-high resolution, multi-shelled dMRI in ex-vivo marmoset monkey brains. We compared the spatial mapping of the MK, NDI, and ND diffusion parameters to the cortical myelin distribution of these brains, with the latter obtained in two ways: First, using histological sections finely co-registered to the MRI, and second using magnetization transfer ratio MRI scans (MTR), an established non-diffusion method for imaging myelin density. We found that, in contrast to DTI parameters, each of these higher order diffusion measures captured the spatial variation of myelin density in the cortex. The demonstration that diffusion parameters exhibit both sensitivity and specificity for gray matter myelin density will allow dMRI to more effectively track human disease, in which myelinated and non-myelinated tissue compartments are affected differentially.

A search for water vapor plumes on Europa by spatially resolved spectroscopic observation using Subaru/IRCS

Abstract We present near-infrared high-dispersion spectroscopic observations of Europa using the Infrared Camera and Spectrograph (IRCS) onboard the Subaru Telescope, seeking direct evidence of water plumes on Europa and exploring spatial variations in plume activity. Using the high spectral/spatial resolution and sensitivity of Subaru/IRCS, our observations have enabled a spatially resolved search for water plumes on Europa. Within our detection limits and time of observation, we found no evidence for the presence of water emission. For a rotation temperature of 50 K, we derived an upper limit on the H$_{2}$O abundance of 9.46 $\times$ 10$^{19}$–5.92 $\times$ 10$^{20}$ m$^{-2}$ in each divided slit area and 4.61 $\times$ 10$^{19}$ m$^{-2}$ in the entire area covered by the slit. This upper limit lies below the inferred water abundance from previous UV observations by the Hubble Space Telescope, while being less sensitive by a factor of three compared to the Keck telescope and by one order of magnitude or more than the James Webb Space Telescope observations. Our results align with previous studies and demonstrate that using Subaru/IRCS is an effective strategy for searching for water plumes on Europa with high spatial resolution. Continued observations across different surface areas and orbital phases are essential to fully characterize Europa’s plume activity and complement upcoming space missions.

Spatiotemporal distribution of sedimentary chloropigments and organic carbon in a shelf sea ecosystem, with a focus on the cold water mass

The Yellow Sea is one of the most thoroughly studied shelf seas in the northwestern Pacific. However, many aspects of the northern Yellow Sea sediments remain poorly understood. Sedimentary chloropigments and total organic carbon (TOC) are crucial components that indicate benthic primary productivity and ecosystem functioning in the marginal sea system. The present study investigated the temporal and spatial variations of sediment chloroplastic pigments (Chl-a and Pha-a) and TOC contents in relation to seasons and the northern Yellow Sea Cold Water Mass (NYSCWM). Decadal trends were also examined using linear regression on time-series data from 12 cruises conducted over a nine-year period (2006–2014). The correlations between sedimentary Chorophy-a (Chl-a), Pheophorbide-a (Pha-a), TOC, and their ratios with other abiotic and biotic factors were analyzed to detect any effects of the NYSCWM on the spatiotemporal distribution of sediment Chl-a, Pha-a, TOC contents, as well as the ecological relevance of their ratios as indicators of food quality (freshness) in the benthic system. The NYSCWM substantially influences the spatial and seasonal distribution of sedimentary Chl-a, Pha-a, and TOC contents. High values of Pha-a, TOC, and the ratios of Pha-a/(Chl-a + Pha-a) and TOC/Chl-a were often observed in the central region of the NYSCWM, where Chl-a showed clear seasonal fluctuations while Pha-a and TOC remained relatively constant. While sedimentary TOC appears to negatively mirror the spatial pattern of primary productivity in the water column, the spatial pattern of sedimentary Chl-a in relation to NYSCWM is less evident. However, the contents of Pha-a and TOC in the central NYSCWM sediments were higher than those at surrounding NYSCWM stations. Surface sediment Pha-a/(Chl-a + Pha-a) ratio was negatively correlated with meiofauna abundance and biomass and positively correlated with nematode/copepod ratio. This finding indicates that the quality of sediment organic matter is important to meiofauna. Conversely, the lower organic degradation rate at the lower bottom temperature of the NYSCWM may explain the observed higher Pha-a and TOC contents in its central area. Time-series data collected over nine years at the NYSCWM stations showed a decreasing trend for Chl-a, while TOC and the ratio of Pha-a/(Chl-a + Pha-a) exhibited increasing tendencies. This trend may imply a reduced quality of food supply to the benthic food web in the shelf sea system, along with degraded ecosystem functioning and service under the impacts of global change and anthropogenic disturbances.

Spatial Variations and Regulating Processes of Groundwater Geochemistry in an Urbanized Valley Basin on Tibetan Plateau

Groundwater resource is crucial for the development of agriculture and urban communities in valley basins of arid and semiarid regions. This research investigated the groundwater chemistry of a typical urbanized valley basin on the Tibetan Plateau to understand the hydrochemical status, quality, and controlling mechanisms of groundwater in arid urbanized valley basins. The results show groundwater is predominantly fresh and slightly alkaline across the basin, with approximately 54.17% of HCO3-Ca type. About 12.5% and 33.33% of sampled groundwaters are with the hydrochemical facies of Cl-Mg·Ca type and Cl-Na type, respectively. Groundwater is found with the maximum TDS, NO3−, NO2−, and F− content of 3066 mg/L, 69.33 mg/L, 0.04 mg/L, and 3.12 mg/L, respectively. Groundwater quality is suitable for domestic usage at all sampling sites based on EWQI assessment but should avoid direct drinking at some sporadic sites in the urban area. The exceeding nitrogen and fluoride contaminants would pose potential health hazards to local residents, but high risks only existed for infants. Both minors and adults are at medium risk of these exceedingly toxic contaminants. Groundwater quality of predominant sites in the basin is suitable for long-term irrigation according to the single indicator of EC, SAR, %Na, RSC, KR, PI, and PS and integrated irrigation quality assessment of USSL, Wilcox, and Doneen diagram assessment. But sodium hazard, alkalinity hazard, and permeability problem should be a concern in the middle-lower stream areas. Groundwater chemistry in the basin is predominantly governed by water-rock interaction (silicate dissolution) across the basin in natural and sporadically by evaporation. Human activities have posed disturbances to groundwater chemistry and inputted nitrogen, fluoride, and salinity into groundwater. The elevated nitrogen contaminants in groundwater are from both agricultural activities and municipal sewage. While the elevated fluoride and salinity in groundwater are only associated with municipal sewage. It is imperative to address the potential anthropogenic contaminants to safeguard groundwater resources from the adverse external impacts of human settlements within these urbanized valley basins.

Fanya Juu terraces improve soil properties of cultivated land in erosion-prone semi-arid area of Ethiopia

Soil erosion is a major process that affect soil fertility and agricultural productivity. To reduce soil erosion by water, physical soil and water conservation measures such as Fanya juu have been widely introduced. However, the study on the performance of those measures against its target is limited. Objective of this study was to assess the effects of physical soil and water conservation (SWC) measures (e.g., Fanya juu) on selected soil physico-chemical properties. Soil samples were collected at 0–20 cm depth of fields treated with Fanya juu and non-treated (without any physical SWC) and analyzed following standard laboratory procedures. Paired sample t-test and one-way ANOVA were used to analyze data. The results of the analysis revealed that clay, silt, sand, soil pH, soil organic carbon (SOC), total nitrogen (TN), available phosphorous (Pav.), and available potassium (Kav.) differed significantly (p < 0.05) between 8-years conserved and non-conserved land. This could be due to the positive effect of conservation measures in reducing erosion. In addition, in the intra- Fanya juu areas clay, sand, Kav., TN, and SOC were significantly varied (p < 0.05), with greater clay, SOC and nutrients at above Fanya juu (deposition area) than below Fanya juu (loss zone), which can be due to the downward movement of organic matter and surface soil and the protection ability of Fanya juu against erosion. In erosion-prone areas, lacking physical SWC measures could degrade essential soil properties as compared to farm fields with physical SWC measures. The spatial variation in intra-Fanya juu area should be amended by integrating additional soil fertility management practices for better effect.

Spatial Variation in Upper Limits of Coral Cover on the Great Barrier Reef

ABSTRACTAimIdentifying the maximum coral cover that a coral community can sustain (i.e., its ‘upper limit’) is important for predicting community dynamics and improving management strategies. Here, we quantify the relationship between estimated upper limits and key environmental factors on coral reefs: hard substrate availability, temperature and water clarity.LocationGreat Barrier Reef (GBR), Australia (over 1400 km).Time Period1990 to 2022.Major Taxa StudiedScleractinian corals.MethodsWe used 32 years of data on coral cover around reef perimeters. Each reef was divided into four wave‐exposure habitats depending on prevailing wind conditions. For each site, we determined if hard coral cover had reached a plateau or upper limit. Next, we extracted existing estimates of hard substrate availability, modelled water temperature and Secchi depth. Then, we quantified the relationship between these environmental variables and the upper limits.ResultsWe found varying upper limits across the GBR, with a median of 33% coral cover and only 17% of the estimated upper limits exceeded 50% coral cover. Upper limits increased towards the southern reefs. Our results show that upper limits increased with increasing hard substrate availability and decreased with temperature and, to a lesser extent, with water clarity.Main ConclusionsThe upper limits estimated in this study are much lower than what is commonly assumed when modelling ecological dynamics, most likely resulting in predicted recovery rates being inappropriately high. Although hard substrate ultimately restricted upper limits, there are mechanisms constraining the proportion of hard substrate that is covered by hard corals. The negative relationship between temperature and upper limits cannot be explained by changes in macroalgal abundance but may be related to changes in species composition. The quantitative relationships between the upper limits of coral cover and environmental variables will provide critical information to prioritise sites for management interventions.

Study of pollution status in urban environment caused by attitude and waste littering behavior of citizens

Littering behavior is one of the main challenges in waste management, especially in big cities. In this study, density and composition of litter in Tehran was investigated and the urban pollution status was calculated by using the clean environment index. The results showed that the average density of litter in the studied locations was 0.182 number/m2. Spatial variation in the litter density showed that the average density in commercial and residential land-uses was 0.22 and 0.14 number/m2, respectively. Cigarette butts (29%), bottle caps (18%), and paper receipts (10%) consisted the largest ratio of the litter composition in the studied locations. Clean environment index for the studied locations was calculated in the range of 2.34 to 10.42. Based on this, 30% of the studied locations were in a clean status and 70% were in a polluted and worse status. The litter density in the city, interviews with citizens, and the results of previous studies showed insufficient awareness of citizens about the consequences of littering in the urban environment, which led to the prevalence of littering behavior. So, the littering behavior by citizens has caused the urban environment pollution and increased health risk. Educating citizens and modifying their behavior to avoid littering is necessary to improve the observed status.