Erosion Potential Research Articles

The erosive effect of various drinks, foods, stimulants, medications and mouthwashes on human tooth enamel.

Two forms of non-carious dental disorder - erosive tooth hard tissue loss and dental erosion - have been increasingly observed in recent years. Dental erosion is the chemical loss of dental hard substances caused by exposure to acids not derived from oral bacteria. Mechanical forces from, for example, the tongue, the cheeks or toothbrushing, increase loss of partly-demineralized tooth surfaces and the cumulative loss of dental hard tissue is defined as erosive tooth wear (ETW). Dental hard tissue losses which occur because of very frequent acid exposure, such as through increased vomiting, but without mechanical stress, are also assigned to tooth erosion. Without prior softening, practically no loss of enamel takes place due to abrasion with the modern Western diet. The present work is a continuation of earlier work. A total of 226 beverages, food, stimulants as well as medicines and mouthwashes were tested for their erosive potential on premolars and deciduous molars covered with a human pellicle. The influence of temperature, phosphate and calcium was also investigated in additional experiments. The change in hardness before and after immersion in the respective test substance was measured and the erosive potential was classified. For each test product, we determined pH and other properties which were possibly related to erosive potential. There were considerable and sometimes surprising differences between the tested products. The addition of phosphate did not influence the erosive potential of the liquids, but calcium did. A modified erosion scheme is presented, which incorporates these and other new findings.

Crop rotation and cultivation effects on Convolvulus arvensis population dynamics in small grain organic cropping systems

Convolvulus arvensis L. Scop. (field bindweed) is a difficult weed to manage in organic cropping systems. Convolvulus arvensis suppression often requires intensive tillage and cultivation practices that have negative impacts on soil quality. To improve C. arvensis management in organic, small grain cropping systems, we compared ten cropping system treatments in a field trial from the autumn of 2017 until harvest of 2020 in Corvallis, MT, USA. Cropping system treatments varied along a gradient of tillage and crop competition, with tillage intensity and competition inversely related. High soil disturbance and no competition occurred in two treatments that remained in tilled fallow for two consecutive years. Six cropping system treatments had different combinations of tillage and annual or biennial crops, including wheat and forages. Two treatments had minimal soil disturbance and maximum competition from two consecutive years of perennial alfalfa. Convolvulus arvensis ramet density was counted annually to estimate changes in treatments over time. Differences in soil chemical and physical properties between treatments were also assessed in the final years of the study. In the first two years, there was no difference in C. arvensis ramet density among cropping system treatments. In the final two years of the study, C. arvensis density remained below one ramet per m2 in intensively tilled fallow treatments and perennial alfalfa treatments, but was much more variable in treatments with more diverse annual and biennial crop rotations with minimal to moderate tillage. The only differences between treatments in soil physical and chemical properties was aggregate stability. Soil from the most intensively tilled fallow treatments had lower soil aggregate stability than six other treatments, indicating higher erosion potential. Our results suggest that annual cropping systems can lead to increased C. arvensis density. Incorporating a perennial forage or an intensively tilled fallow period can prevent C. arvensis expansion in small grain organic cropping systems, but the perennial forage can protect and enhance soil quality.

Implications of Atmospheric Nondetections for Trappist-1 Inner Planets on Atmospheric Retention Prospects for Outer Planets

JWST secondary eclipse observations of Trappist-1b seemingly disfavor atmospheres >∼1 bar since heat redistribution is expected to yield dayside emission temperature below the ∼500 K observed. Given the similar densities of Trappist-1 planets, and the theoretical potential for atmospheric erosion around late M dwarfs, this observation might be assumed to imply substantial atmospheres are also unlikely for the outer planets. However, the processes governing atmosphere erosion and replenishment are fundamentally different for inner and outer planets. Here, an atmosphere–interior evolution model is used to show that an airless Trappist-1b (and c) only weakly constrains stellar evolution, and that the odds of outer planets e and f retaining substantial atmospheres remain largely unchanged. This is true even if the initial volatile inventories of planets in the Trappist-1 system are highly correlated. The reason for this result is that b and c sit unambiguously interior to the runaway greenhouse limit, and so have potentially experienced ∼8 Gyr of X-ray and extreme ultraviolet–driven hydrodynamic escape; complete atmospheric erosion in this environment only weakly constrains stellar evolution and escape parameterizations. In contrast, e and f reside within the habitable zone, and likely experienced a comparatively short steam atmosphere during Trappist-1's pre-main sequence, and consequently complete atmospheric erosion remains unlikely across a broad swath of parameter space (e and f retain atmospheres in ∼98% of model runs). Naturally, it is still possible that all Trappist-1 planets formed volatile-poor and are all airless today. But the airlessness of b (and c) does not require this, and as such, JWST transit spectroscopy of e and f remains the best near-term opportunity to characterize the atmospheres of habitable zone terrestrial planets.

Potential of tropical expansive clays as natural sealing layer in nuclear waste repository system: a preliminary study

The issue of radioactive waste disposal in Malaysia is frequently debated, particularly in terms of human and environmental long-term well-being. The creation of a repository with minimal hazard risk and cost implications is a major environmental concern related to nuclear waste. Expansive clay has distinct characteristics that are readily available in the environment and can serve as a natural barrier (sealing system) against the migration of radioactive and chemical pollutants. In this study, the physico-chemical and microstructural properties of 2 types of tropical soils with dominant clays mineral (vermiculite and montmorillonite) were investigated to better understand the potential of these clays as natural sealing in nuclear waste repository systems. Based on preliminary findings, both types of soil have been classified as alkaline soil (>7) with high swelling capacity (FSI) (>80%) and high consistency (LL>50%; PI>30%). The microstructural study demonstrates that vermiculite clays have a noticeable flaky morphology and a porous structure as compared to montmorillonite, indicating that the soil can absorb more water, hence decreasing its infiltration capability. Pinhole dispersion analysis reveals that montmorillonite clay is more prone to dispersion due to the presence of sodium ions and has a higher erosion potential than vermiculite clay. Future Malaysian stakeholders may employ this research to establish a long-term plan for the management of radioactive waste through the usage of natural resources.

Estimated potential erosion in the Papaloapan River: Modeling efficiency and uncertainty

El conocimiento global de las consecuencias del cambio de vegetación y uso de suelo en las fases del ciclo hidrológico y la calidad del suelo aún está en ciernes. Esta tarea es particularmente desafiante en las regiones tropicales donde las tasas de deforestación alcanzan los niveles máximos reportados y el monitoreo es limitado. Tal es el caso de México, donde el cambio de cobertura y la erosión hídrica afectan a más de la mitad del territorio nacional. En este contexto, se usó el modelo SWAT para estudiarla erosión hídrica asociada con las variaciones en el caudal condicionadas por la trayectoria de cambio de la cobertura vegetal en seis periodos entre1986 y 2018 en dos subcuencas del río Papaloapan. Basados en la evaluación combinada de tres estadísticos de eficiencia y dos de incertidumbre, 6 de los 10 periodos calibrados mostraron buenos ajustes en la simulación de la descarga con KGE > 0.70 y P-factor > 0.70. Los resultados mostraron a mediano plazo una disminución en la producción de sedimentos en las dos subcuencas estudiadas, posiblemente relacionada con la recuperación de los bosques en las cabeceras de las cuencas. A pesar de los buenos resultados de las simulaciones, el análisis detallado de las fuentes de incertidumbre en regiones con monitoreo limitado es tan importante como la validación con datos medidos de buena calidad para mejorar el desempeño y la confianza de los modelos y soportar de forma adecuada la toma de decisiones

Spatial and Temporal Variation of Soil Conservation on The Southern Slopes of Qilian Mountains, China

Soil is essential to human survival, and soil health directly impacts human production and life; therefore, monitoring soil erosion has been the primary concern for scientists worldwide. Using the Revised Universal Soil Loss Equation (RUSLE), we analyzed soil conservation, actual soil erosion, and potential soil erosion on the south slope of the Qilian Mountains in China from 2000 to 2015. We drew the following conclusions: (1) The spatial distribution characteristics of soil conservation (Ac) and potential soil erosion (Ap) in the study area remained highly consistent, with a decreasing trend in the northwest and an increasing trend in the southeast. (2) The soil conservation capacity of the study area is increasing while the LSCA area is decreasing significantly. (3) The influence of R and Ap on Ac is powerful, whereas the influence of Ar on Ac is moderate. (4) The change in soil conservation decreases as DEM increases but increases as NDVI increases.

Analysis of Physical Characteristics and Soil Degradation Due to Erosion and Rehabilitation Recommendation Based on GIS in Protected Forest Area of Mount Sirimau

Forest areas are designated as protected forests if they function as a provider of clean water reserves, erosion control, city lungs or other functions. Disruption of forest land resources has an impact on changes in the physical properties of the soil and soil degradation due to erosion. Objectives of this study were: 1) to examine the relationship between soil physical properties, 2) to determine soil degradation due to erosion, 3) to examine the relationship between soil physical properties and the level of soil degradation due to erosion, 4) to determine recommendations for land rehabilitation. Research observations were made based on 15 sample areas representing 212 land units. All analyzes were carried out based on Geographic Information Systems (GIS). The physical properties of the soil studied included texture, structure, pore distribution, permeability, particle density and oven dry mass density; whereas soil degradation analysis was based on RUSLE: A=RKLSCP (Renard et al., 1997), and correction of the erosion model A=0.2547RKLSCP (Talakua S.M. and Osok, 2017. The rehabilitation recommendations analyzed were erosion tolerance, potential erosion and CP-maximum. Study results were: 1) The correlation between physical properties was significant (P-value = 0.000*-0.018*) with a positive correlation coefficient (0.163-0.999) and negative one (0.199-0.998); 2) The average erosion rate was: light 3.60 t/ha/year (1425.20 ha), moderate 32.03 t/ha/year (410.28 ha), heavy 108.95 t/ha/year (946 .2 ha), very heavy 426.83 t/ha/year (457.44 ha); 3) There was a significant correlation between the physical properties of the soil and the amount of erosion with a P-value = 0.000*–0.029* with a positive (0.152-0.161) and a negative (0.150-0.151) correlations; 4) Recommendation for rehabilitation are agroforestry patterns combined with tillage and planting of plants according to contour lines on slopes of 0–8%, planting grass in strips, planting low ground cover on high density plantation crops and maintaining secondary and primary forests.

Modelling and mapping of soil erosion risk based on GIS and PAP/RAC guidelines in the watershed of Tassaoute (Central High-Atlas, Morocco)

Morocco watersheds, which provided many ecosystem services necessary for the socio-economic life of rural communities, are experiencing significant change and environmental problems. Therefore, examining potential soil erosion considered a major problem in the Moroccan highlands is very important to prioritize high erosion severity areas. Keeping in view of the above aspects, the present study aimed to evaluate and map areas at risk of water erosion in the upstream Tassaoute watershed (central High Atlas, Morocco), using the Priority Action Program/Regional Activity Center (PAP/RAC) method associated with Geographic Information Systems (GIS) and remote sensing. The PAP/RAC approach consisted of integrating the natural factors that influence water erosion, namely slope, lithology, vegetation cover and land use. This method provided an accurate cartographic product that reflects the reality of the state of soil degradation and the qualitative assessment of erosion. The generated erosion risk map of the study area showed that the phenomenon of erosion threatens this basin, especially in the middle and downstream, such that 40% of the basin surface has significant erosion and the high and very high degree of erosion represented 27% of the total surface of the study area. These results therefore demonstrated the PAP/CAR model reliability in assessing and mapping of water erosion risks in the upstream Tassaoute basin.

Salt distribution of earthen heritage site wall and its mechanism in northern China

Salt damage is one of the most important causes of the destruction of earthen heritage sites. The study of salt distribution is of great significance for identifying potential erosion patterns of earthen heritage sites. In previous studies, the salt distributions in only a few earthen heritage sites have been analysed. In this study, 35 typical earthen heritage sites in northern China were investigated that are more widely distributed and more universal than those in previous studies. The salt content and natural water content at different locations on the earthen wall were compared, and the differences in the soluble-salt distribution for different regions of northern China were explored. The results show that the salt content of the loose layer was higher than that of the surface crust, except in the Subash Buddhist Ruins. The difference for the Subash Buddhist Ruins may be the special dual-porosity structure with inter-aggregate pores (large pores) and intra-aggregate pores (small pores) in the coarse-grained soil. The threat of soluble salt to earthen heritage sites in northeast China was found to be far less than that in northwest China, which may have been caused by different rainfall and evaporation intensities. Finally, the reasons for the salt distribution, the prevention of salt damage, and the application of the results to earthen heritage sites in northern China were examined.

Erosive potential of ice tea beverages and kombuchas

Objectives Kombuchas and other tea-based beverages are often perceived as healthy products despite the lack of knowledge on their effects on oral health. This in vitro study determined the erosive potential of commercial kombuchas, and ice teas compared to cola drinks. Materials and methods The pH and fluoride content of 7 kombuchas and 18 tea drinks were measured with ion-selective electrodes. Calcium dissolution from hydroxyapatite grains was quantified by atomic absorption spectroscopy after beverage exposure. The effect of beverages on the enamel surface was visualized by scanning electron microscopy (SEM). Distilled water, and cola drinks were used as negative and positive controls. Results The kombuchas exhibited lower pH values (2.82–3.66) than the ice teas (2.94–4.86), but still higher than the cola drinks (2.48–2.54). The fluoride concentration varied between 0.05 and 0.46 ppm and for 7 beverages the concentration was below the detection limit. The calcium release for kombuchas was 198–746 mg/l, for ice teas 16.1–507 mg/l, and for cola drinks 57.7–71.9 mg/l. Twenty-two beverages had a significantly greater calcium release than the cola drinks (p = .009–.014). The surface etching of the enamel was seen in the SEM analysis after beverage exposure. Conclusions Tea-based beverages have even higher erosive potential than cola drinks. Kombuchas especially, displayed a considerable erosive potential.

Effects of conservation practices on global wind erosion control: Evidence from experimental data

AbstractWind erosion represents one of the major land degradation forms that significantly threatens sustainable development across the globe. A series of conservation practices have been widely developed and tested in order to effectively reduce wind erosion rates in non‐irrigated dry and semi‐dry lands. However, a comprehensive investigation regarding the efficacy of conservation practices and potential impacting factors on erosion control at the global scale has not been undertaken. In this study, a synthesis was conducted, based on data from global experimental plots, to comprehensively examine the efficacy of varying conservation practices, and their effectiveness at reducing erosion, in different geographical regions, under varying climatic conditions, and with different soil properties. The results showed that conservation practices were able to reduce wind erosion rates by over 52% globally. Straw use and soil stabilizer were the most effective measures in wind erosion control, which could reduce erosion rates by over 70%. Wind erosion control efficacy of conservation practices differed among climatic zones, continents, and countries. Notably, the lowest efficacy was observed in dry climatic zones. Erosion control efficacy highly depended on climatic conditions, such as mean annual precipitation (MAP), mean annual temperature (MAT), wind speed, and soil properties, such as water content and clay content. We further observed a positive correlation between wind erosion reduction rates and straw mulching rates, suggesting a straw mulching rate of at least 40% was necessary in order to reach a potential erosion reduction rate of 70%. To sum up, this study illustrates that the overall efficacy of conservation practices in wind erosion control is highly effective at the global scale, but the specific effects vary among different regions, and depend on conservation practice type, climatic condition, and soil property. The lower erosion reduction rate of dry regions at high erosion risk suggests the high erosion control pressure, and more effective measures should be considered and developed. The results of this study are, importantly, complementary to existing wind erosion control guidelines.

Primary trapeziectomy with Regjoint(TM), a poly-L/D-lactide spacer, a two-year follow-up study with new radiological assessment tool.

The aim of this retrospective study was to evaluate the potential bony erosion and the clinical and radiological results of primary trapeziectomy with RegjointTM interposition, in patients with peritrapezial arthritis. Data were recorded on twenty patients over a period of two years (January 2015-December 2016). On average 24 months, patients were reconvened for a post-operative evaluation (subjective evaluation of pain, function and patient satisfaction; clinical evaluation with strength and mobility measures; post-operative X-rays). On X-rays, 2 criteria were evaluated: the bony erosion and the shortening of the thumb column (trapezium+metacarpal height measure, ratio between first and second metacarpal bones, a new radiological assessment tool based on a trapezoid relationship gradation). In most patients, surgery relieved pain and offered good functional results, according to the Quick Disabilities of the Arm, Shoulder and Hand scale. Following surgery, our patients showed a subjective improvement, both in terms of pain and functional results. For plain X-ray, only 3 patients showed an osteolytic lesion (maximum of 2.8 millimeters) on the first metacarpal base. A statistically significant reduction in the thumb column height was generally observed on follow-up X-rays. However, all of these radiologic changes were present without any clinical impact. We show that the RegjointTM spacer is an available alternative in the surgical treatment of peritrapezial arthritis. We did not highlight any significant associated complications, no important adverse tissue reaction or bone erosion, no pain or functional disorder. Type of study/level of evidence Therapeutic IV.

Identification of Erosivity Potential on Tropical Zone Using Spatial Method

As a geological process that wears away soil, rock, or dissolved material, erosion may result in the loss of soil layers that are rich in nutrients for plant growth and reducing soil ability to absorb and store water. High rainfall causes a high level of erosivity which can lead to the increase of erosion intensity. Therefore, in predicting erosion, rain condition needs to be considered the most, especially for the tropics. This study was conducted in Samboja District, East Kalimantan Province, Indonesia. The purpose of this study is to create zoning potential for erosion based on topographic correlation with land cover and support practices factors spatially in a map form. The uniform distribution of soil types allows the integration of the erodibility factor together with the erosivity factor. Several erosion equations suitable for tropical areas were used to estimate the erosion, using the BMKG rainfall data for the last 16 years (2006-2020). The results of the study are maps of erosion potential distribution at minimum, maximum, and average conditions. The change in the distribution of potential erosion from the minimum to the average occurred only at very limited points, and it was almost negligible. A significant change was found under condition of maximum erosion potential. The striking change in the zone of potential erosion under condition of the average to the maximum potential for erosion occurred in the zone from Class III to Class IV, and Class IV to Class V.

Global Analysis of the Cover-Management Factor for Soil Erosion Modeling

Land use and management practices (LUMPs) play a critical role in regulating soil loss. The cover-management factor (C-factor) in Universal Soil Loss Equation (USLE)-type models is an important parameter for quantifying the effects of LUMPs on soil erosion. However, accurately determining the C-factor, particularly for large-scale assessments using USLE-type models, remains challenging. This study aims to address this gap by analyzing and comparing the methods used for C-factor quantification in 946 published articles, providing insights into their strengths and weaknesses. Through our analysis, we identified six main categories of methods for C-factor quantification in USLE-type modeling. Many studies have relied on empirical C-factor values for different land-use types or calculated C-factor values based on vegetation indices (VIs) in large study areas (>100 km2). However, we found that no single method could robustly estimate C-factor values for large-scale studies. For small-scale investigations, conducting experiments or consulting the existing literature proved to be more feasible. In the context of large-scale studies, employing methods based on VIs for C-factor quantification can enhance our understanding of the relationship between vegetation changes and soil erosion potential, particularly when considering spatial and spatiotemporal variations. For the global scale, we recommend the combined use of different equations. We suggest further efforts to develop C-factor datasets at large scales by synthesizing field-level experiment data and combining high-resolution satellite imagery. These efforts will facilitate the development of effective soil conservation practices, ensuring sustainable land use and environmental protection.

Impact of Repurposing Forest Land on Erosion and Sediment Production. Case Study: Krupanj Municipality—Serbia

Erosion is one of the main causes of soil degradation and sediment production. The amount of eroded material that reaches rivers and lakes depends on the terrain but also on the climatic and hydrological characteristics of the basin, as well as the applied land management method. The intensity of sediment production is in direct correlation with the land use type. Repurposing forest land as mining, urban and infrastructural development areas, etc., significantly affects sediment production. Shrinking of forests and unplanned agricultural production are just some of the factors that intensify erosion processes and increase the amount of eroded material, also triggering climate change and the onset of prolonged dry and rainy periods, which increase the risk of erosion in sloping terrain and intense sediment production. The paper presents the correlation between the change in the forest land use method, on the one hand, and soil erosion and sediment production, on the other, by analysing segments of river basins in the territory of the Serbian Municipality of Krupanj. The modelling of sediment production was based on data collected from the experimental territories. The method of erosion potential, data analysis, and procession in GIS surrounding were used for calculating sediment production in the experimental areas. The greatest loss of soil was perceived in the terrain with little or no vegetation on steep slopes covered with material prone to water erosion. The smallest production of sediment was noted in the terrain with vital forest vegetation. The results received point to the heterogeneous estimates of land loss, enabling the modelling of sediment production in wider basin areas and the analysis of the impacts of different land management factors on the erosion processes.

Seismic signatures and site characterization of an intermittent stream in dry and flood conditions: an implication for soil losses and landslide triggering

Identifying ambient noise-based (ANb) signatures together with the erosion-prone site conditions retrieved from georadar attribute analysis of streams can help in the estimation of their erosive potential (EP) that promotes reverie landslides and soil losses in the fluvial valleys. This is particularly imperative on flooding or rainy days, leading to stronger erosion-prone conditions (colluvium and boulders) of the valley beds. Developing such research direction can benefit the local communities, as is the case with the Cerrado region of Brazil, where these phenomena have high destructive potential with social, economic, and climatic implications. For the present study, a seasonal stream in the Federal District of Brazil was investigated by ANb monitoring supported by ground penetration radar (GPR) for site characterization. The ANb monitoring was conducted (at a safe distance) with a seismometer over several durations of dry and rainy conditions. The power spectral density (PSDs) as a function of several weather conditions (rainfall, wind speed, and pressure), time–frequency spectrograms, and ambient noise displacement root mean square (dRMS) were computed. This analysis also considered the single station horizontal-to-vertical spectral ratio (HVSR), where rain, wind, pressure, river flow and anthropogenic signatures were evident (at selective frequency ranges). Multi-peaks that emerged on the HVSR curve were further analyzed to identify amplitude and frequency changes, with the three peaks shifting on average to a lower position during the rainy period. The GPR amplitude and waveform variation features were attributed to the stratigraphy of the floodplain and regions susceptible to erosion, such as erosion-prone lithological spots, which provide the basis for non-destructive monitoring tools that enable the detection of “seismic signatures” and weak spots of the fluvial channels for improving environmental management.

Spark Discharge Synthesis and Characterization of Ge/Sn Janus Nanoparticles.

Germanium-tin nanoparticles are promising materials for near- and mid-infrared photonics thanks to their tunable optical properties and compatibility with silicon technology. This work proposes modifying the spark discharge method to produce Ge/Sn aerosol nanoparticles during the simultaneous erosion of germanium and tin electrodes. Since tin and germanium have a significant difference in the potential for electrical erosion, an electrical circuit damped for one period was developed to ensure the synthesis of Ge/Sn nanoparticles consisting of independent germanium and tin crystals of different sizes, with the ratio of the atomic fraction of tin to germanium varying from 0.08 ± 0.03 to 0.24 ± 0.07. We investigated the elemental and phase composition, size, morphology, and Raman and absorbance spectra of the nanoparticles synthesized under different inter-electrode gap voltages and the presence of additional thermal treatment directly in a gas flow at 750 °C. The research shows that the in-flow thermal treatment of aerosol-agglomerated nanoparticles produced special individual bicrystalline Janus Ge/Sn nanoparticles with an average size of 27 nm and a decreasing absorption function with a changing slope at 700 nm.

Drainage network rearrangement during the formation and segmentation of a Paleogene intraplate half-graben: Insights from fluvial captures records and longitudinal profiles

Rivers play an important role in modifying landscapes through denudation processes, which can be influenced by changes in tectonics, climate and eustasy, causing erosive pulses and river capture events that alter the geometry and topology of the drainage network. Therefore, drainage networks are not static features over time and are modified and rearranged by shifts in their boundary conditions until a state of dynamic equilibrium is reached in the landscape. The region of the Paraíba do Sul Middle Valley (PSMV), in Southeastern Brazil, has important records of captures and recent drainage rearrangements, which show a state of transition in the landscape and, consequently, the reorganization of drainage networks. This region is in the central segment of the Continental Rift of Southeastern Brazil (CRSB), a prominent tectonic feature that can be described as an intraplate half-graben. While fluvial profiles and fluvial gradient indices are valuable tools for studying the landscape evolution, their application to investigate the erosive power of rivers and how the topography of a half-graben affects the rearrangement of the drainage network over geological time is still limited. Specifically, there is a need to explore how the topography of the active border of a half-graben differs from that of the flexural border in terms of river network organization and fluvial erosion patterns. This study aims to characterize the different stages of rearrangements of the drainage network and their relation with the events of formation and segmentation of a half-graben. A total of 21 basins were analyzed in both Fault and Flexural Border sectors, extracting geomorphic parameters, such as slope, drainage area, concavity, χ and ksn. A more specific study was carried out in areas where river captures were recognized as been related to the half-graben formation and segmentation events. The ksn calculated for the main rivers demonstrates that the formation of the rift and its consequent configuration in half-graben granted a greater erosive power for the basins that drained the active fault of the rift, represented by the basins of the Fault Border Sector of the study area. The tectonic events registers in the fluvial system were analyzed using the χ method and the main migration tendency of the dividers was extracted from the difference in the values of this parameter in areas close to the interfluves. With this, it becomes evident that the geometric configuration imposed in the half-graben establishes, from the beginning of the rift phase, an important control on the erosion potential of the rivers located in the active and flexural borders. This control resulted in ancient river captures, currently exposed as inflections in the main river channels towards the local depocenters, thus demonstrating that this type of tectonic event can generate disturbances in the river system that can be observed even today, tens of millions of years after it happened.

Operational forecasts of wave-driven water levels and coastal hazards for US Gulf and Atlantic coasts

Predictions of total water levels, the elevation of combined tides, surge, and wave runup at the shoreline, are necessary to provide guidance on potential coastal erosion and flooding. Despite the importance of early warning systems for these hazards, existing real-time meteorological and oceanographic forecast systems at regional and national scales, until now, have lacked estimates of runup necessary to predict wave-driven overwash and erosion. To address this need, we present an approach that includes wave runup in an operational, national-scale modeling system. Using this system, we quantify the contribution of waves to potential dune erosion events along 4,700 km of U.S. Atlantic and Gulf of Mexico sandy coastlines for a one-year period. Dune erosion events were predicted to occur at over 80% of coastal locations, where waves dominated shoreline total water levels, representing 73% of the signal. This shows that models that neglect the wave component underestimate the hazard. This new, national-scale operational modeling system provides communities with timely, local-scale (0.5 km resolution) coastal hazard warnings for all wave conditions, allowing for rapid decision-making related to safety and emergency management. The modeling system also enables continued research into wave-driven processes at a broad range of coastal areas.

Micro-flow imaging for in-situ and real-time enumeration and identification of microplastics in water

Microplastics (MPs) are emerging contaminants that have recently gained global attention. Current identification and quantification methods are known to be time-consuming, labor-intensive, and lack consensus on protocol standardization. This study explored the potential of micro-flow imaging (MFI) technology for rapid and in-situ identification and enumeration of MPs in water using two (2) MFI-based particle counters. Advantages, limitations, and recommendations for using MFI for MPs analysis were discussed. MPs with diverse physical (i.e., microbeads, fragments, fibers, and films) and surface (i.e., reflectivity, microporosity, color) characteristics were analyzed to understand the detection capabilities and limitations of MFI technology. Results demonstrated that MFI effectively automates most manually obtained particle features, such as size, color, object intensity and shape descriptors. It imparts consistency and reduces the subjective nature of results, thus enabling reliable comparison of the generated data. The particles can be further categorized based on their circularity and aspect ratio providing further insight into the shape and potential erosion of MPs in the environment. Transparent particles, often missed with other techniques such as microscopy, were detected by the MFI technology. The ability to assign particle IDs to MPs was an important advantage of the MFI technology that enabled the further investigation of selected MPs of interest. The limitations of the MFI technology were apparent in samples with high particle concentrations, with reflective MPs, and in the presence of bubbles. The color of the background against which the image was captured also influenced the detection accuracy. Procedural modifications during sample analysis and improvements in image analysis can assist in overcoming these challenges. MFI requires minimal sample preparation and gives real-time imaging data, making it a prime candidate for field monitoring in surface water systems in addition to laboratory analysis. With the potential application of machine learning and similar developments in the future, MFI-based particle counters are well-positioned to meet an important need in in-flow and real-time identification and enumeration of MPs.