Anthropogenic Agents Research Articles

Impact of Abiotic and Biotic Environmental Conditions on the Development and Infectivity of Entomopathogenic Nematodes in Agricultural Soils.

Many organisms, including beneficial entomopathogenic nematodes (EPNs), are commonly found in the soil environment. EPNs are used as biopesticides for pest control. They have many positive characteristics and are able to survive at sites of application for a long time, producing new generations of individuals. The occurrence of populations depends on many environmental parameters, such as temperature, moisture, soil texture, and pH. Extreme temperatures result in a decrease in the survival rate and infectivity of EPNs. Both high humidity and acidic soil pH reduce populations and disrupt the biological activity of EPNs. Nematodes are also exposed to anthropogenic agents, such as heavy metals, oil, gasoline, and even essential oils. These limit their ability to move in the soil, thereby reducing their chances of successfully finding a host. Commonly used fertilizers and chemical pesticides are also a challenge. They reduce the pathogenicity of EPNs and negatively affect their reproduction, which reduces the population size. Biotic factors also influence nematode biology. Fungi and competition limit the reproduction and survival of EPNs in the soil. Host availability enables survival and affects infectivity. Knowledge of the influence of environmental factors on the biology of EPNs will allow more effective use of the insecticidal capacity of these organisms.

The double life of trichomes: understanding their dual role in herbivory and herbicide resistance.

Understanding the evolutionary forces that maintain phenotypic variation in ecologically relevant traits has long been one of the central goals of evolutionary ecology. While the maintenance of variation in plant defense is most often hypothesized to be due to trait trade-offs or spatiotemporal variation in herbivore abundance, the role that heterogeneous selective agents may play on the maintenance of variation in plant defense is less examined. Trichomes are hair-like appendages on plant surfaces that can defend against multiple damaging agents such as pathogens, herbivores, and UV radiation. It is currently unknown however if conflicting selection from such heterogeneous agents of damage may act to maintain the variation observed in trichome traits. Here, we assess whether trichomes serve as an herbicide resistance trait and how it coincides with the conventionally studied defensive strategy of herbivory resistance. In a series of experiments, we exposed the annual invasive velvetleaf (Abutilon theophrasti) to glyphosate (active ingredient in "Roundup") to investigate whether trichome traits (type and density) are linked to herbicide resistance and to test whether herbicide influences selection on plant trichomes. We found that an increased proportion of branched trichomes positively impacted herbicide resistance and chewing herbivory resistance. We also found evidence that glyphosate imposes positive selection on branched trichomes in velvetleaf. Overall, our results indicate that branched trichomes can contribute to both herbicide and herbivory resistance, serving a concordant rather than conflicting role to reduce plant injury. Our findings further suggest that novel anthropogenic agents of selection can alter the composition of plant defense traits, potentially impacting trait-mediated interactions among external stressors.

Anthropogenic aerosols mask increases in US rainfall by greenhouse gases

A comprehensive understanding of human-induced changes to rainfall is essential for water resource management and infrastructure design. However, at regional scales, existing detection and attribution studies are rarely able to conclusively identify human influence on precipitation. Here we show that anthropogenic aerosol and greenhouse gas (GHG) emissions are the primary drivers of precipitation change over the United States. GHG emissions increase mean and extreme precipitation from rain gauge measurements across all seasons, while the decadal-scale effect of global aerosol emissions decreases precipitation. Local aerosol emissions further offset GHG increases in the winter and spring but enhance rainfall during the summer and fall. Our results show that the conflicting literature on historical precipitation trends can be explained by offsetting aerosol and greenhouse gas signals. At the scale of the United States, individual climate models reproduce observed changes but cannot confidently determine whether a given anthropogenic agent has increased or decreased rainfall.

Prominence of environmental and anthropogenic agents on the occurrence of coral reef bleaching syndrome and coral diseases

Coral reefs are the most productive ecosystems on Earth. They ensure the conservation of biodiversity and are a live habitat for 25% of all marine organisms. The main relationship on the coral reef is the symbiosis between corals and algae from the genus Symbiodinium (commonly called zooxanthellae). The authors of this publication have characterized and described the factors limiting the occurrence of coral reefs, including: water temperature, salinity, access to sunlight, contamination, physicochemical and hydromechanical parameters of water. Moreover anthropogenic threats to coral reefs have been specified, including diving tourism, ecological disasters (e.g. oil spills) and the development of marine aquaristics. Rapid changes in the basic living conditions are dangerous for corals and their symbionts and may cause the unsuitability of the new environment resulting in diseases such as coral bleaching. Corals bleaching is a disease associated with the break of the coral and algae relationship which results in a coral reef death on a global scale. Awareness of these negative factors, often related to human activity, may allow us to better understand the ecological processes that are the basis of reef functioning and might enable us to prevent and oppose to the changes and ecological recessions of coral reefs.

Assessment of urban wetlands loss and fragmentation using land use and land cover change and guidostoolbox: A study of Chorrillos district, Lima.

The coastal landscape of the Chorrillos district is an ecosystem characterized by hosting the largest population of migratory and resident bird species in Lima, including the Protected Natural Area of the Pantanos de Villa Wildlife Refuge (RVSPV). In response to wetland loss, this study aims to explore the process of natural landscape fragmentation in the Chorrillos district, including the RVSPV, from 1985 to 2021 to identify the impact of anthropogenic agents on structural connectivity. The methodology involves (i) an analysis of land cover and land use (LULC) using the MapBiomas Peru Collection 1.0 Platform, (ii) a patch accounting analysis, (iii) an analysis of Area Density in the Foreground (FAD), and (iv) an analysis of Morphological Spatial Patterns (MSPA) using the GuidosToolbox (Graphic User Interface for Image Object Description and Shapes-GTB) Version 3.304. The results indicate a hierarchy of disturbed patches, with the largest patch (RVSPV) displaying specific spatial processes that contribute to landscape transformation and persistence. The ecological function of the patches and habitat links demonstrate the benefits of connectivity and environmental exchange between fragments, aiming to counteract landscape loss.

Risk Assessment, Interdependencies, and Source Appraisal of Bioaccumulated Heavy and Essential Metals in Seafood as Pollutants.

Fish as seafood is a bioindicator for chemical substances like trace metals in the water systems that accumulate in fish bodies. Fe and Zn as essential and Pb, Ni, and Cd as heavy metals were quantitatively analyzed in fish muscle samples by an atomic absorption spectrophotometer (Perkin Elmer, Model AAnalyst-700). Fe and Zn's results agreed with the food quality guidelines. Fe was the highest in the range of 2.6-9.4 in mg kg-1. The Zn content indicates the contribution of anthropogenic agents through the food chain. Ni > Pb > Cd was found in marine fish species and Pb > Ni > Cd in freshwater fish. The results have been explored for source appraisal of bioaccumulated trace metals and categorized selected marine and freshwater species based on characteristics (like life cycle and habitats) by applying multivariate principal component analysis to risk assessment parameters. The Pearson correlation coefficients were applied to the risk assessment parameters for interdependencies of metals. Interestingly, synchronized outcomes were obtained with trace metal data. The study results were interpreted in the context of the fish type, habitat, surroundings, feed, life cycle, etc. The living habitats strongly affect trace metal accumulation, target hazard quotient (THQ), and target cancer risk (TR) attributes. The fishermen's community was at higher risk for carcinogenic effects than other seafood consumers. Overall, determinations for fish species were under safe limits as described by international regulatory bodies (FAO, WHO, ANHMRC, WAA).

The use of a video and a small-scale model for rain-induced landslides in geotechnical engineering education

Small-scale physical models of geotechnical problems are thought-provoking didactic tools that motivate students by arousing their curiosity and facilitating the understanding of physical phenomena and theoretical concepts. This work presents the development of an educational video about slope stability failures and its contributing factors. It shows several small-scale models built in a glass wall tank measuring 150 x 50 x 10 cm. Layers of fine gravel were placed on a sloping surface of polystyrene to represent a slope with a layer of residual soil on rock. Toy houses and cars were used to represent anthropogenic agents, and water with dye represents the groundwater flow. Each model depicts a different scenario of shallow slope failure. The objective of the video is to show that most slope failures in urban areas result from natural and anthropogenic factors. Several influence factors are shown: porewater level rise, excavation, surcharge application, and solid urban waste deposition. The 6-minute video has had more than 130,000 views on YouTube. Thanks to its simple and concise language, the video is shown in basic education and science museum, as well as in graduate and undergraduate courses. A questionnaire survey was carried out with undergraduate students to assess how helpful the video was for the learning process. This article explains the construction of the model, the video script, and the strategies for its use, as well as its reception. It was found that the video promoted motivational and learning benefits of providing context, establishing relevance, and teaching inductively.

The development of an in vitro propagation and conservation system for the endangered serpentine fern Asplenium cuneifolium Viv.

Asplenium cuneifolium Viv. is an endangered fern species restricted to European serpentine rocks, which face a risk of being easily damaged by both natural and anthropogenic agents. Establishing a comprehensive system of effective micropropagation and long-term storage of this species is therefore desirable. Freshly collected spores of A. cuneifolium were subjected to direct storage at 5 °C and in liquid nitrogen (LN). The viability of spores stored at 5 °C decreased by 10% after 1 year, whereas storage in LN did not change the initial spore viability even after 3 years. For the initiation of the gametophyte culture, disinfected spores were sown onto half-strength Murashige and Skoog medium (½MS) supplemented with 0.06 M sucrose. Following 6 months, abundant proliferation of secondary gametophytes was achieved. For the cryopreservation of gametophytes, encapsulation-vitrification and encapsulation-dehydration, were compared. Of these two methods, encapsulation-vitrification ensured survival of gametophytes of 64.5–93%, while encapsulation-dehydration guaranteed their 100% viability. The acceleration of syngamy on secondary gametophytes was achieved using a medium with macro- and micronutrients reduced to the 1/8 of the MS free of NH4NO3 and vitamins. The syngamic sporophytes could be multiplied by somatic embryogenesis (SE) induced on etiolated stipe explants in an ½MS medium devoid of any plant growth regulators. Adding 0.3 M of sucrose to the medium almost quadrupled the efficiency of the SE. The genetic stability of gametophytes after cryopreservation, as well as sporophytes obtained from them, was confirmed by flow cytometry, amplified fragment length polymorphism, and inter-simple sequence repeat markers.

The Toxicity of Synthetic Pesticides in the Niger Delta Region: A Review

The Niger Delta region of Nigeria with a vast and resourceful ecosystem which has welcomed diverse agricultural practices and crude oil exploration. On the other hand, being a wetland it has also become a breeding ground for major pests of agricultural and public health interest. One major problem is the proliferation of mosquitoes which have obliged the intense usage of pesticides. Typically, pesticides are agents meant to control targeted organisms (pests) that have caused adverse effects to man and his environment. Due to the excessive and inappropriate usage of pesticide they drift and get linked to contaminable environmental media such as water, air and soil. Human exposure can occur from inhaled spray drift, accidental ingestion, runoffs and in a broad sense through food chains. Pesticides find their way into different ecosystems causing adverse effects to non-target organisms, most of these non-target organism lacks metabolites to degrade these toxic pesticides residue in their cells and tissues; hence accumulate them and transfer them to other organisms via food chain which could cause acute and chronic effect. In addition, industrial and municipal effluents have a more toxic synergistic effect with pesticides. Toxic effects of pesticides can be controlled by; adhering to safety instructions from manufacturers of pesticides, thorough washing of agricultural produce, use of gloves and mask by the applicant and other safety measures. In addition, toxicological research and advocacy should be more active in the Niger Delta Region as well as proper and active regulation of pesticides usage to comply with minimal residual limits of pesticides and anthropogenic agents.

LAND USE CHANGE ASSESSMENT IN KWANA-UKU FOREST RESERVE AND SAMERI COMMUNITY FORESTS ADAMAWA STATE, NIGERIA

This research assessed land use change of Government and Community forests in Ganye and Jada Local Government Areas of Adamawa State. Data were collected from two selected Forests. The study utilized land use datasets to examine the spatial extent and distribution of forest cover in both areas over two decades. The data used for analysis were satellite imageries downloaded from google earth between the year 2000 and 2020. In an effort to determine the change in land cover of the study area, three different images at ten-year (10) interval were used (2000, 2010 and 2020). Student t-test was used to compare the results of land use classification. Results obtained indicated that all the land cover classes changed (either increased or decreased) in the study areas over the given study period. Findings also unveiled a significant net negative change in forest land cover class with extensive significant increase in bare- surfaces and a remarkable reduction in vegetation. Expansion in bare surfaces in Sammeri community and Kwana uku forest study sites between year 2000 and 2020 were (+514.42%) and (+261.59%) at the expense of a reduction in forested areas which were (−46.75%) and (−56.95) respectively. Additionally, results proved forest stocks or resources were being depleted by anthropogenic agents, owing to their hostile effects which included; fuel wood collectors, farmers, animal grazing, bush burning and unregulated logging of trees. The study recommends the need for the implementation of sustainable forest management practices in the two forests, with further extension to other notable reserves across the country.

Mapping Uncounted Anthropogenic Fill Flows: Environmental Impact and Mitigation

Fill material flows created by land development earthworks are anthropogenic agents that generate massive energy use from their heavy loads. However, formal quantification of these flows has been neglected. We use Osaka Prefecture in Japan as a case study to quantify fill flows and associated CO2 emissions. We collected data on fill flows, including fill generation and acceptance. We mapped these publicly uncounted fill flows and calculated the CO2 emissions from the associated energy use. We also simulated a scenario in which optimized shortest-distance matching is achieved between fill generators and acceptors. We estimated the current fill flows based on distance and weight and broke down the total by type of site and activity. We compared our estimates of current fill flows with estimates from our matching simulation and found the simulation could achieve an 8448 km reduction in flow length and a 5724 t-CO2 reduction in emissions associated with transportation. We discussed the implications of flexible matching, especially in different construction sectors, and the importance of continuous, spatially geo-referenced monitoring of these fill flows toward further environmental impact mitigation. The approach presented here could apply to assessing environmental loads arising from landform changes in other cities and lead to development of a new regional- and global-scale fill material science in the Anthropocene.

Understanding the surface temperature response and its uncertainty to CO<sub>2</sub>, CH<sub>4</sub>, black carbon, and sulfate

Abstract. Understanding the regional surface temperature responses to different anthropogenic climate forcing agents, such as greenhouse gases and aerosols, is crucial for understanding past and future regional climate changes. In modern climate models, the regional temperature responses vary greatly for all major forcing agents, but the causes of this variability are poorly understood. Here, we analyze how changes in atmospheric and oceanic energy fluxes due to perturbations in different anthropogenic climate forcing agents lead to changes in global and regional surface temperatures. We use climate model data on idealized perturbations in four major anthropogenic climate forcing agents (CO2, CH4, sulfate, and black carbon aerosols) from Precipitation Driver Response Model Intercomparison Project (PDRMIP) climate experiments for six climate models (CanESM2, HadGEM2-ES, NCAR-CESM1-CAM4, NorESM1, MIROC-SPRINTARS, GISS-E2). Particularly, we decompose the regional energy budget contributions to the surface temperature responses due to changes in longwave and shortwave fluxes under clear-sky and cloudy conditions, surface albedo changes, and oceanic and atmospheric energy transport. We also analyze the regional model-to-model temperature response spread due to each of these components. The global surface temperature response stems from changes in longwave emissivity for greenhouse gases (CO2 and CH4) and mainly from changes in shortwave clear-sky fluxes for aerosols (sulfate and black carbon). The global surface temperature response normalized by effective radiative forcing is nearly the same for all forcing agents (0.63, 0.54, 0.57, 0.61 K W−1 m2). While the main physical processes driving global temperature responses vary between forcing agents, for all forcing agents the model-to-model spread in temperature responses is dominated by differences in modeled changes in longwave clear-sky emissivity. Furthermore, in polar regions for all forcing agents the differences in surface albedo change is a key contributor to temperature responses and its spread. For black carbon, the modeled differences in temperature response due to shortwave clear-sky radiation are also important in the Arctic. Regional model-to-model differences due to changes in shortwave and longwave cloud radiative effect strongly modulate each other. For aerosols, clouds play a major role in the model spread of regional surface temperature responses. In regions with strong aerosol forcing, the model-to-model differences arise from shortwave clear-sky responses and are strongly modulated by combined temperature responses to oceanic and atmospheric heat transport in the models.

Impact of Ship Traffic on the Characteristics of Shelf Sediments: An Anthropocene Prospective

Humans have been sailing across seas and oceans for thousands of years. However, the story of large ships capable of affecting coastal ecology and shelf sedimentary processes is only about 100 years old. Modern large seagoing vessels with a draft of 10–20 m can cause resuspension of seabed sediment, erosion of the channel slope and shoal, enhancement of seafloor sediment activity and thickening of the active layer, thereby having a significant impact on seabed topography and sedimentation processes. However, little is known about the effects of this anthropogenic agent on shelf sedimentation due to limited observational data. Here, two sediment cores were collected from a shipping lane used by vessels of 5,000- to 50,000-ton off the coast of China to analyze their sedimentary properties, with focus on both the grain size and elements. It was found that ship disturbance selectively modified the sedimentary record, with the fine-grained sediment becoming increasingly unstable. In addition, there was a reduction in grain size of sediment finer than 6.25 Φ, which decreased by 11% after the disturbance by ship. Biogenic elements that were closely related to the ecological environment were significantly altered, with Br/Cl, Si/Ti, and Ca/Ti ratios all becoming significantly smaller. This indicated that frequent disturbance caused by ships had reduced the productivity in the waters near the shipping lane. In terms of sensitivity to the effects of ship navigation, the sedimentation response was relatively rapid and began to emerge from the commencement of ship navigation, whereas the ecological response became evident later than the sedimentation response and only appeared after a significant growth in the maritime transportation of China. Following the comparison of the two sediment cores, we propose that the constant rate of supply (CRS- with ship disturbance)–constant initial concentration (CIC- without ship disturbance) dual dating model be used to establish a dating framework in waters frequently disturbed by ship. This type of anthropogenic sedimentary dynamic process and its sedimentary–ecological effects deserve attention on this era where there is a surge in shipping globally. Shipping lanes present an excellent area for quantitative studies on the impacts of human activity and defining the Anthropocene in the context of shipping.

Effect and Response of Quercus ilex subsp. ballota [Desf.] Samp. Seedlings From Three Contrasting Andalusian Populations to Individual and Combined Phytophthora cinnamomi and Drought Stresses.

Quercus ilex L. is the dominant species in the Mediterranean forest and agrosilvopastoral ecosystem “dehesa.” Currently, this forest species is threatened by natural and anthropogenic agents, especially by the decline syndrome, which is caused by Phytophthora cinnamomi and drought periods. Although the morphological and physiological responses of Q. ilex to combined stress (P. cinnamomi and drought) have been examined already, little is known at the molecular level. In this study, we studied the effect and response of 8-month seedlings from three contrasting Andalusian populations (Seville [Se], Granada [Gr], and Almeria [Al]) to the individual and combined stresses of P. cinnamomi and drought from morphological, physiological, biochemical, and proteomics data. Whereas, seedling damage (leaf chlorosis and necrosis) and mortality were greater under the combined stresses in the three populations, the effect of each individual stress was population-dependent. Resilient individuals were found in all the populations at different percentages. The decrease in leaf chlorophyll fluorescence, photosynthetic activity, and stomatal conductance observed in undamaged seedlings was greater in the presence of both stresses, the three populations responding similarly to drought and P. cinnamomi. Biochemical and proteomic analyses of undamaged seedlings from the two most markedly contrasting populations (Se and Al) revealed the absence of significant differences in the contents in photosynthetic pigments, amino acids, and phenolics among treatments. The Se and Al populations exhibited changes in protein profile in response to the different treatments, with 83 variable proteins in the former population and 223 in the latter. Variable proteins belonged to 16 different functional groups, the best represented among which were protein folding, sorting and degradation, carbohydrate, amino acid, and secondary metabolism, photosynthesis, and ROS scavenging. While photosynthetic proteins were mainly downaccumulated, those of stress-responsive were upaccumulated. Although no treatment-specific response was observed in any functional group, differences in abundance were especially marked under the combined stresses. The following variable proteins are proposed as putative markers for resilience in Q. ilex, namely, aldehyde dehydrogenase, glucose-6-phosphate isomerase, 50S ribosomal protein L5, and α-1,4-glucan-protein synthase [UDP-forming].

Wild ungulates compound herbicide-mediated simplification of early successional plant communities in forest plantations

Understanding the degree to which management interacts with ecological processes to drive the structuring of biodiversity remains a central challenge in ecology. For instance, the effects of herbivores on post-disturbance vegetation development may depend on the degree to which anthropogenic interventions have altered plant communities.We hypothesized that by simplifying plant species composition at local scales, intensive forest management practices should amplify herbivore-mediated changes in early-successional vegetation development and diversity at multiple levels of biological observation (i.e., alpha, beta, and gamma diversity). To test this hypothesis, we implemented a six-year experiment that manipulated post-timber harvest vegetation establishment via a gradient in vegetation management intensity (i.e., herbicides), and quantified compositional changes with and without wild-ungulate herbivores.Increasingly intensive herbicide treatments suppressed broadleaf vegetation and reduced plant diversity at alpha and gamma levels, while the effects of wild-ungulates were most evident in measures of community change and beta diversity for a commonly applied treatment type. Following the broad-spectrum and follow-up herbaceous treatment combination, herbivory contributed to the suppression of vegetation cover, slowing plant community development by 21%, and resulting in 27% less among-plot heterogeneity (i.e., lower beta diversity). We found no effects of herbivory alpha diversity, but the divergence in communities subjected to herbivory resulted in disparate community composition and lower gamma diversity.Herbicide and herbivore-mediated alterations in community composition was due the suppression of broadleaf species and subsequent release of common herbivory-tolerant herbaceous species. Although herbivory also slowed vegetation development without herbicides, the high diversity and abundance of broadleaf forages likely buffered untreated sites from the herbivore-mediated alterations of plant composition at alpha, beta, and gamma levels.The variation in effects of herbicide and herbivory in this experiment highlight the importance of testing for interactions between natural and anthropogenic agents on vegetation development and quantifying diversity responses beyond local scales. These results also suggest that large herbivores may contribute to management-induced simplification of young forests, with potential implications for successional processes and regional biodiversity conservation.

Effects of Different Ammonia Levels on Tribenuron Methyl Toxicity in Daphnia magna.

The present study investigates the toxicity of the herbicide tribenuron methyl (TBM) as an anthropogenic agent and ammonia as an abiotic factor on Daphnia magna at environmentally relevant concentrations. These stressors may coexist in surface waters in agricultural regions. To achieve this objective, D. magna were exposed to TBM at a nominal concentration of 0.81μg/L in association with a low ammonia (LA) concentration of 0.65mg/L and a high ammonia (HA) concentration of 1.61mg/L in acute toxicity tests of 96-h duration and chronic toxicity tests of 21-day duration. The D. magna also were exposed to TBM, HA, and LA singly. The D. magna were analysed for various biomarkers of sublethal toxicity. Glutathione peroxidase (GPx), glutathione S-transferase (GST), cholinesterase (ChE) enzyme activities, and levels of thiobarbituric acid reactive substances (TBARS) and total protein were determined spectrophotometrically. Mitochondrial membrane potential (MMP) was analysed by microscopy with fluorescence staining. Cytochrome c and 5' AMP-activated protein kinase (AMPK) were analysed by Western blotting. Morphometric properties were examined microscopically. This is the first study in which AMPK, an indicator of intracellular energy, was measured in D. magna. GST and ChE enzyme activities and TBARS and total protein levels did not change during acute exposures (i.e., 96h) in all treatments. GPx activity increased in D. magna from the HA + TBM treatment compared with single-exposure groups. The level of cytochrome c protein was elevated in D. magna from the LA and LA + TBM treatments. AMPK protein levels increased in all treatments with daphnids, except in the LA group. MMP was depolarised in D. magna from all treatments, whereas the most notable change was observed in HA + TBM mixture group in chronic exposures. The results show that GST and ChE may not be sensitive biomarkers for evaluating the sublethal toxic effects to D. magna exposed to environmentally relevant concentrations of ammonia and TBM. Acute and chronic exposure to ammonia and TBM probably caused an energetic crisis in D. magna. Therefore, AMPK and MMP are promising biomarkers for these toxicants.

The Implications of Area Morphology and Particulate Matters’ Distributions on the Kwa Iboe River Basin Restoration, Southeastern Nigeria

The upsurge pressure from natural and anthropogenic agents at the Kwa Iboe River ecology necessitates the exploration of the association of area morphology and particulate matters’ distributions with a view to developing sound policy for the protection and sustainability of its heritage. This study uses direct field survey and laboratory techniques. The area morphology of the Kwa Iboe River Basin (KIRB) was delineated using Shuttle Radar Topography Mission on a 30 meter resolution for the determination its size. Using stratified and systematic sampling methods, eight sampled sub-units comprising one first-order stream, six fourth order tributaries, and the estuary were selected. A set of core bedload samples were collected along each transect during the months of November (2017), February (2018), and July (2018); homogenized, treated, and analyzed to ensure standard compliance to the National Research Laboratory Umudike. Data generated were analyzed descriptively and inferentially. The results showed the dominant of mean sand fraction across seasons and sub-basins. A linear regression model of the influence of area morphology on the distributions of particulate matters generated a high coefficient of 0.954 that explained 90.9 percent of the total variance. The analysis of variance test of the influence at 0.05 confidence level showed that variations in area morphology have no significant influence on particulate matters’ (sand, silt, clay, organic matter, and organic carbon) distributions in KIRB. The study recommended (i) strict implementation of the basin management plans to avert natural and anthropogenic activities that accelerate siltation and drying of Kwa Iboe River tributaries, losses of terrestrial habitats, and pollution of surface water. (ii) Enforcement of existing laws to facilitate stringent control of human exploitative excesses with obvious negative implications on the KIRB ecology in this post-modern age.

A relação sociedade-natureza nos territórios paleodunares do rio São Francisco/BA

The São Francisco River has outlined in its course many geological-geomorphological features, and among them it is possible to highlight the paleodune fields, built in other periods of the Earth's history. These sandy features have, over the years, lost their original characteristics attributed not only to natural erosive agents, but also to anthropogenic agents, since the relationship established between society and nature has not been harmonious. In this sense, this research deals with the relationship of the inhabitants and riverside dwellers of the paleodunar territories around the São Francisco River in the municipality of Casa Nova/BA, with nature., and their respective impacts. It is a qualitative-quantitative research, exploratory, bibliographical and field. The findings indicate that the paleoenvironment is in very considerable stages of degradation, requiring the implementation of conservation proposals that can mitigate the damage caused to the physical and natural environment and which, consequently, has affected the local society.

Exploring the hydromorphological response to human pressure in Tagus River (1946–2014) by complementary diagnosis

Different levels of human pressures have modified the dynamism and the morphological pattern of most riparian environments worldwide. Among the anthropogenic agents, flow regulation by dams, gravel mining; artificial land use and land cover changes together with climate change are the most frequently studied. Medium and short term geomorphological adjustments and riparian vegetation cover changes have been frequently studied by using a variety of methodological approaches, with the diachronic analysis of orthophotographs as the most common starting point. The main objective of this research is to assess the spatio-temporal evolution of geomorphological conditions and riparian vegetation cover along a 38 km-long reach of the Tagus River, analysing the last 70 years, in order to understand the main drivers leading to those changes. To that purpose, a complementary diagnosis has been carried out by combining different approaches: (1) Simple geomorphological indicators, (2) Specific geomorphic indexes, (3) Landscape metrics and (4) Transition matrices, together with the analysis of flow discharges. Results show that River Tagus has suffered a narrowing process (67.7%) along the entire study period (1946–2014) close to a decrease in width ratio of 2.1 m/year. However, the narrowing trend was not stable along the entire period, with the most dramatic reduction happened between 1956 and 1975 with a decrease ratio around 7.1 m/year for that subperiod. At the same time, woody riparian vegetation, grass and shrubs covers decreased in comparison with 1946 photo while agriculture land increased within initial riparian zone. By combining different approaches, we note the progressive impoverishment of geomorphic status that is more severe when we consider the area (-49%) of fluvial landforms instead of their number (-26%), in parallel with the fragmentation and complexity pattern found for both vegetated and bare gravel bars according to landscape patchiness analysis. Our results show that geomorphic status in the 4 sub-reaches have decreased, although in the case of sub-reach 1 and 4 the response presents a delay with the more important decrease occurring from 1975 to 1999. This geomorphological evolution is explained by the synergic combination of different human pressures along time. Initially, flow regulation by large dams influenced this evolution, but water-transfer since 1979 and floodplain occupation by farmland activities were more relevant with the time. River dynamism, figured out as the amount of area subject to rejuvenation (i.e., evolution toward more pioneer stages) and succession processes (i.e., evolution toward more mature stages), was reduced more than a half along the period 1946–1975, while it completely changed after 1975 where they became close to 10% of the initial dynamism. Thus, our results show by the combination of different approaches that River Tagus channel has become immobilized, reduced with a simplified morphology and its riparian vegetation lost its dynamism converted into a mature wood.

Rationally engineered nanosensors: A novel strategy for the detection of heavy metal ions in the environment

Heavy metal ions (HMIs) have been mainly originated from natural and anthropogenic agents. It has become one of biggest societal issues due to their recognised accumulative and toxic effects in the environment as well as biological media. Key measures are required to reduce the risks posed by toxic metal pollutants existing in the environment. The increased research activities of HMIs detection, and use of technologies based on electrochemical detection that combine with engineered nanomaterials, is a key promising and innovative strategy that can potentially confine heavy metal poisoning. Deep understanding of the characteristics of the physicochemical properties of nanomaterials is highly required. It is also important to interpret the parameters at the nano-bio interface level that merely affect cross-interactions between nanomaterials and HMIs. Therefore, the authors outlined the state-of-the-art techniques that used engineeringly developed nanomaterials to detect HMIs in the environment. The possible novel applications of extensive and relatively low-cost HMIs monitoring and detection are discussed on the basis of these strengths. Finally, it is concluded by providing gist on acquaintance with facts in the present-day scenario along with highlighting areas to explore the strategies to overcome the current limitations for practical applications is useful in further generations of nano-world.