Sedimentation Rates Research Articles

Framed reef modules: a new and cost‐effective tool for coral restoration

Coral reef ecosystems worldwide are facing significant damage due to climate change and human disturbances. Consequently, restoration actions have been implemented to repair degraded reef areas. However, many restoration efforts have been hindered by severe environmental conditions, which can hamper restoration success and create challenges in developing cost‐effective coral reef restoration methods. To address this, we conducted a study to test a low‐cost reef restoration tool known as “framed reef modules” (FRMs), specifically aiming to mitigate the impacts of typhoons. We measured the growth rates (after 300 days) and survivorship (after 400 days) of Acropora hyacinthus and A. microphthalma fragments located at different distances from substrates (H0, H10, H30, and H45). The FRMs were exposed to multiple typhoons, and despite the harsh conditions, they remained undamaged. For comparison, we also examined basalt grid plates buried in gravel. After 400 days, the H45 FRMs showed the highest survival rates (A. hyacinthus 86% and A. microphthalma 90%) compared to H30 FRMs (A. hyacinthus 80% and A. microphthalma 84%), H10 FRMs (A. hyacinthus 4% and A. microphthalma 24%), and H0 FRMs (A. hyacinthus 3% and A. microphthalma 22%). It was found that transplanted corals with a height of at least 30 cm from the substrate demonstrated resilience against impacts caused by macroalgae, turf algae, and sedimentation rates. This study showed the effectiveness of an ecological engineering approach using FRMs to enhance the three‐dimensional complexity of restored reefs and rehabilitate coral reefs damaged by typhoons. Furthermore, this method offered reduced costs and improved reef resilience.

Estimating Reservoir Sedimentation Rates and Storage Capacity Losses Using High‐Resolution Sentinel‐2 Satellite and Water Level Data

AbstractIn nearly all reservoirs, storage capacity is steadily lost due to trapping and accumulation of sediment. Despite critical importance to freshwater supplies, reservoir sedimentation rates are poorly understood due to sparse bathymetry survey data and challenges in modeling sedimentation sequestration. Here, we proposed a novel approach to estimate reservoir sedimentation rates and storage capacity losses using high‐resolution Sentinel‐2 satellites and daily in situ water levels. Validated on eight reservoirs across the central and western United States, the estimated reservoir bathymetry and sedimentation rates have a mean error of 4.08% and 0.05% yr−1, respectively. Estimated storage capacity losses to sediment vary among reservoirs, which overall agrees with the pattern from survey data. We also demonstrated the potential applications of the proposed approach to ungauged reservoirs by combining Sentinel‐2 with sub‐monthly water levels from recent satellite altimeters.

A multiscalar and multiproxy geoarchaeological approach to site formation processes at the Middle and Upper Palaeolithic site of La Roche-à-Pierrot, Saint-Césaire, France

The site of La Roche-à-Pierrot in Saint-Césaire (Charente-Maritime, France) produced a succession of Mousterian, Châtelperronian and Aurignacian occupations, and continues to play a central role in debates concerning the Middle-to-Upper Palaeolithic transition. The source of controversy surrounding the site relates to ambiguities concerning the overall archaeological sequence, the cultural association of the human remains found at the site and the limited number of robust absolute dates. Here, we present the results of a multiscalar, multiproxy geoarchaeological investigation of the site's sedimentary sequence. Our study integrates geomorphology, field lithostratigraphy, microstratigraphy, geochemistry and absolute dating methods (radiocarbon and optically stimulated luminescence) designed to characterize site formation processes. We propose a site formation model involving the evolution of a karstified limestone cliff from a semi-closed system to an exposed slope deposit, with sediments at the base of the cliff accumulating under periglacial conditions of MIS3, broadly between ca. 59.9 ± 3.9 ka and ca. 37.7 ka. The lowermost Mousterian occupations took place in a semi-closed, sheltered space in which sedimentary rates were low, involving mainly cryoclastic roof spall and episodic percolation of fine-grained sediment. This depositional environment generated a Mousterian archaeological palimpsest in the proximal area and translocated downslope. Subsequent Mousterian, Châtelperronian and Aurignacian remains embedded within diamictons were deposited in an open-air context, on a sloping surface at the apex of a palaeotalus, and possibly above the site, at the top of the cliff. The resulting diachronous surfaces and immature deposits were subject to solifluction and slopewash, with low sedimentary rates. Our geoarchaeological study sheds new light on previously noted spatial inconsistencies in the archaeological sequence and constitutes a rigorous framework for further archaeological research at the site, highlighting the potential of a multiscalar, multiproxy site formation research to improve stratigraphic investigation of Palaeolithic sites in similar geomorphological contexts.

DISTRIBUTION OF SEDIMENTS AT THE MAIN MOUTHS OF THE KILIA DENUBE DELTA AND THEIR SEDIMENTATION VALUE

Purpose: In the article the basic purpose is determination and analysis by distribution natural conformities of deltaic sediments after its movement across every arm, under impact of sea waves separation and influence of the coastal hydrogenetic factors. The noted peculiarities have important practical significance. Additionally, they explain the marine margin dynamics and sediment forming of deltaic types. Data & Methods: This article is based on natural datum of sedimentary material sampling around of marine margin of the dynamical Danube delta, NW Coast of the Black Sea. The sampling was made in region from head of Zhebriyan bay in north side to Musura bay in south side during 2010–2020 period in different environment and synoptical conditions. Laboratory elaborations were made with representative instruments usage and mathematical methods of treatment. Samples of suspended and coarse drifts were elaborated and analyzed within conditions of different sides of marine margin of the Delta. Results: The general definitions of protruding deltas state that the delta cone of protrusion is composed of alluvial sediments. But in the studied delta, a significant place is occupied by coastal-marine facies of wave action. In addition, the newest river sedimentary material changes during the passage through deltaic watercourses (especially long ones). Therefore, on the delta coast within the marine wave field, sediments with a slightly changed composition appear. Therefore, several facies environments can be defined in the Danube delta: a) typically riverine; b) alluvial-delta; c) coastal sea with separated sediments; d) aeolian center of influence of the wind factor; e) typical marine on the outer strip of the sea. We recommend that all the mentioned features be taken into account during the analysis of the Danube’s flow sediments to the bottom of the Black Sea and the determination of sedimentation rates. The main paper outlines provisions of the lithodynamic model of delta-type sediments’ formation in the conditions of a generous influx of river sediments, a steep underwater slope, a non-tidal sea and strong wave action. Fractions of 0.1–0.01 mm dominate along the coastal edge, with integral Md = 0.048 mm, and the concentration of fractions > 1.0 mm is sharply reduced. The content of CaСО3 is lower in comparison with sediments in Zhebriyansk Bay in the area of final dispersion of a strong alongshore flow of sand sediments. Within the studied deltaic natural system, the surrounding physical and geographical conditions actively influence the composition of delta sediments, create a sedimentary diversity of the facies network and tracts. The different composition of sediments leads to different density of the sediment layer, with different amounts of water content, mostly from 1% to 5%, different influence of river and sea factors. Accordingly, specific facies cells of the botanical and zoological substrate are formed in the areas of dominant influence of these factors. In the new parts of the delta, some cells settle first, others later, and the third – last in the life cycle. Therefore, in different areas, we meet the settlement of the primary territories of the delta by different plants and animals that are located in different parts of the warm period of the year.

Effects of Etanercept and Adalimumab on Serum Levels of Cartilage Remodeling Markers in Women with Rheumatoid Arthritis.

Tumor necrosis factor α inhibitor (TNFαI) therapy is associated with a significant inhibition of radiographic progression, resulting in improved physical function and quality of life among patients with rheumatoid arthritis (RA). The mechanism by which TNFαI prevent joint destruction is still unknown. In this study, the effect of 15-month anti-TNF-α therapy in combination with methotrexate on circulating levels of biochemical markers of cartilage turnover in female RA patients was assessed. Serum levels of collagen type II C-terminal cleavage neoepitope (C2C), C-terminal propeptide of type II collagen (PIICP), cartilage oligomeric matrix protein (COMP), and matrix metalloproteinase-3 (MMP-3) were evaluated using immunoassays at baseline and 15 months after the start of TNFαI treatment. Baseline COMP, C2C, and MMP-3 levels and C2C/PIICP ratios were significantly higher in women with RA compared with those observed in the healthy subjects. No differences in PIICP levels between the controls and the women with RA were observed. After 15 months of TNFαI treatment, serum levels of C2C, COMP, and MMP-3 decreased, whereas the levels of PIICP increased but were still not different from those of the controls. These changes were accompanied by significantly reduced C2C/PIICP ratios. Before the start of TNFαI therapy, serum levels of COMP significantly correlated with the patients' ages (p < 0.05) and their 28-joint disease activity score values based on their erythrocyte sedimentation rates (DAS28-ESR; p < 0.05). Moreover, multiple linear regression analysis showed that baseline COMP levels retained a significant association with DAS28-ESR value (β = 287.74, p = 0.022, R2 model = 0.25) after model adjustments. The largest area under the ROC curve was obtained for C2C/PIICP ratios (AUC: 0.830, 95% CI: 0.727-0.932, p < 0.001). Our results suggest that long-term anti-TNF-α therapy combined with MTX has a beneficial effect on cartilage remodeling that is associated with clinical improvement among RA patients. Serum C2C/PIICP ratios may help to monitor the effectiveness of anti-TNF-α treatment among RA patients.

Harbour Hydro-Morphodynamics and Freshwater Discharges: The La Spezia Arsenale Case

The hydrodynamics and sediment transport at the microtidal harbour of La Spezia Arsenale (Liguria, Italy) were studied through a numerical approach, with the objective of providing useful information for: (1) the understanding of the hydro-morphodynamics of microtidal harbour settings and (2) the operation management and planning for the Arsenale, the pivotal harbour for the Italian Navy. Three different scenarios were used to parametrically gain knowledge on the role of extreme (100-year return period) meteomarine forcing. FUNWAVE and Delft3D were used to simulate, respectively, the wave propagation from the open sea toward the Arsenale and the influence of two freshwater streams on the basin circulation. The first scenario was aimed at understanding the effect of wind waves and swell on the basin dynamics; the second scenario was set up to inspect the role of the rivers’ discharges on the Arsenale hydro-morphodynamics; the third scenario combined all of the above forcings. All the simulations also included the tidal forcing and were run under two different wind directions. We found that the hydrodynamics inside the Arsenale were mainly influenced by the tide and the wind; the former caused the water to enter/exit the basin during the flood/ebb phases, respectively, and the latter influenced the circulation cell, whose sense of rotation depended on the wind direction. In addition, the discharge of the Lagora stream, debouching into the sea close to the Arsenale entrance, partially entered the basin and created an eddy whenever its direction was opposite to that of the wind-forced circulation cell, while the Caporacca stream, flowing directly into the Arsenale, mainly fed the dominant circulation without altering it. On the other hand, the morphodynamics were strongly affected by the rivers’ discharges, which were solely responsible for the supply of sediment to the basin. Also, the major influence on the sediment transport was exerted by the rivers and the wind forcing. Small sedimentation rates were observed in the Arsenale close to the rivers’ mouths, particularly after the occurrence of the rivers’ discharges, while no siltation due to waves took place. This study evaluated for the first time the influence of freshwater streams flowing nearby/into the Arsenale, representative of semi-enclosed microtidal ports located in the vicinity of rivers. It was found that the contribution of the rivers to the hydro-morphodynamics of the Arsenale cannot be neglected; indeed, it represents one of the main forcings of the harbour dynamics and should, therefore, be considered from a management viewpoint.

Distribution of artisanal fishing gears with impacts on sedimentation and benthic macroinvertebrate assemblages in Songkhla Lake, the largest lagoon in Thailand

The present study investigated the distribution and diversity of stationary fishing gears in Songkhla Lake and assessed the effects of the most abundant gear in the lake, the standing trap, on sedimentation and the abundance of benthic macroinvertebrates. Our survey revealed that six types of fishing gear were used: standing traps, fyke nets, fish aggregating devices, seabass net cages, small traps and stationary lift nets. The type of fishing gear used depended on the depth of water. The density of installed standing traps reached a maximum of 357 traps/km2, which was the highest density of any fishing gear installed on the lake. They were mainly set in the middle part of the lake, where the water was less than 2 m deep. Sedimentation was examined inside and outside the areas influenced by standing traps. Sediment samples were collected with sediment traps in the northeast and southwest monsoon seasons. Sedimentation rates inside and outside the areas influenced by standing traps differed at some sites but the pattern was not consistent across seasons. Sedimentation rates were higher in the northeast monsoon season with the average rate 1132.32 ± 43.73 (mean ± SE) g m−2day−1 when precipitation and run-off were higher and 323.98 ± 10.68 g m−2day−1 in the southwest monsoon or dry season. Moreover, the proportion of finer clay particles was greater in the sediment from the areas influenced by traps. Benthic macroinvertebrate communities between the two areas were different. A bivalve, Potamocorbula sp., which dominated benthic macroinvertebrate assemblages, had a higher abundance in areas influenced by traps. The effects of stationary fishing gears on sedimentation and benthic macroinvertebrates highlighted in this study suggest that the long-term deployment of these gears may affect food chain dynamics in this lagoon system. Ultimately, a proper regulation of the use of these gears may be needed.

Mercury deposition in the Eastern Mediterranean: Modern fluxes in the water column and Holocene accumulation rates in abyssal sediment

Modern and past mercury (Hg) fluxes in the oceanic water column and abyssal sediments are poorly quantified. Here, we investigated the particulate transfer of Hg in the water column of the ultra-oligotrophic Ionian Sea (Eastern Mediterranean) with sediment traps during a one-year period, and its accumulation in the deep central abyssal plain using sediment cores comprising the last 10 ka. The Hg concentrations in the particles collected in the sediment traps varied from 112 to 401 ng g−1 and enabled quantifying annual Hg fluxes of 2.0, 2.5, and 2.5 μg m−2 a−1, for traps deployed at 250, 1440, and 2820 m deep, respectively. Hg collected in the upper trap originates from atmospheric deposition, including Saharan dust, which is scavenged by the biological pump. Higher Hg fluxes found at mid-depth and near-bottom than in the upper water layer are attributed to lateral advection under the mixed layer of Hg-rich resuspended sediments from the Adriatic continental margin. In the abyssal sediment, Hg concentrations range from 15 to 134 ng g−1 with the highest levels in the Sapropel S1. Methylmercury concentrations varied from 0.06 to 0.24 ng g−1 following the distribution of total Hg, with evidence of its specific accumulation at the oxidized front of the sapropel. We estimated that <1.8% of the total Hg in the sedimentary column was diagenetically reallocated. The reconstruction of historical Hg accumulation rates (HgAR) during the Holocene shows low pre-anthropogenic values (∼0.3 μg m2 a−1 before 4 ka BP), increasing up to ∼0.9 μg m2 a−1 during the late Iron Age and the Roman period (1.5–2.5 ka BP), and up to 2.9 μg m2 a−1 during the Industrial Era. During the Sapropel S1 period (∼6–10 ka BP), HgARs rose to 6.4 μg m−2 a−1 likely due to the intensity of the Hg removal by the biological pump, the organic matter preservation, along with high inputs of Hg-rich terrigenous matter and a possible restricted recycling in the atmosphere. Hg accumulation in the Ionian Sea deep sediment is found ∼3-fold lower than those in the western Mediterranean abyssal plain.

SHORT-TERM COASTAL LANDSCAPE EVOLUTION IN CIREBON BAY USING COASTLINE ENVIRONMENT ANALYSIS

The landscape of Java’s north coast is dominated by a mild slope covered by soft sediment, which faces many environmental issues. These issues have been identified, and the simple technique of overlaying Landsat imagery shows the evolution of the landscape along the coast. Survey campaigns in 2006 and 2018 verified the Landsat overlay, and the 210Pb dating analysis aids in describing the sedimentation rate along the coast. The results demonstrate that accretion evolution dominates exclusively in Cirebon’s coastline landscape, with coastal gains reaching 1463.88 ha over four decades and the sediment rate from 1977–1997 estimated at 0.27–0.33 cm/year. Compared to the earlier decade, the recent two periods from 1998 to 2018 demonstrate a more extensive desire for progressive accretion affected by the longshore sediment transport. Hence, special attention should be paid to the northern coast of Java to estimate the sedimentation rate and the advanced coast.

Monitoring of nature-based solution for stabilizing eroded muddy coastline of the Chao Phraya Delta, Thailand

The Chao Phraya Delta (CPD), Thailand’s largest delta and low-lying muddy coast, has experienced shoreline recession for over six decades due to relative sea-level rise. A nature-based solution, bamboo fences, widely used in low-lying tropical areas, have been intensely applied along the CPD coastline during the last two decades. This study evaluated the effectiveness of bamboo fences in protecting eroded CPD coastlines using remote sensing data (aerial photographs, satellite imagery, and LiDAR observation data). Results from this study indicate that the effectiveness of bamboo fences in trapping sediment decreased over time due to the deterioration of bamboo, which generally deteriorates within four years. Additionally, the installation of multiple layers of bamboo fences did not directly increase the effectiveness of the structure in stabilizing the CPD coastline. It was also found that the mangrove shoreline can be successfully regenerated in the CPD coast where the seabed is higher than 0.5 m amsl. Because of the short life of the bamboo fences, the bamboo fence may not be the best solution for coastal protection and sustainable coastal management in a low-lying area with a high rate of shoreline recession and a low rate of sedimentation.

Global distribution of geothermal gradients in sedimentary basins

The heat budget of sedimentary basins is determined by heat transfer across the lithosphere-asthenosphere boundary and lithospheric heat sources, such that the tectonic evolution of their host continental and oceanic lithosphere ultimately impact the present-day heat flow and average geothermal gradients. Recent increase in availability of publicly-accessible geothermal gradient measurements across the world provides an opportunity to globally assess the dominant controls on the thermal regime of sedimentary basins. Thus, we compile a global dataset of ∼ 152,000 unique data points with constrained bottomhole temperature measurements and assess the relationships between geothermal gradient and selected independent tectonic variables, including crustal and lithospheric thicknesses, crustal age, sediment thickness, and basin type. The results show that in both oceanic and continental settings, geothermal gradients exhibit a non-linear, systematic variation with the tectonic variables. We find that oceanic geothermal gradients decrease with increasing crustal age and lithospheric thickness. Geothermal gradients in the continents show no clear relationships with thermotectonic crustal age, but decrease with increasing crustal and lithospheric thicknesses. Gradients drop significantly at 1.5 km sediment-cover thickness, likely reflecting the effect of high sedimentation rates, but show a striking rise at > 12 km thicknesses, potentially influenced by thinned lithosphere and thermal blanketing effects. The commonly-assumed ‘normal’ gradient of 25 °C/km for continents is only valid for a narrow range (1.5–12.5 km) of sedimentary cover-thickness, and oceanic ‘normal’ gradient may be as high as 50–75 °C/km for > 20 Ma crustal age and > 50 km-thick lithosphere. We show that, conditionally, crustal age may best predict average geothermal gradients in oceanic settings, and lithosphere thickness in continents. Further, we observe that tectonic basin types exhibit distinct ranges of gradients that reflect their prevalent tectonic and geodynamic origins. Despite the complexities of determining shallow-crustal thermal conductivities, the results provide insights that fingerprint distinct tectonic settings based on the broad distribution of their geothermal gradients.

Paleoenvironmental study of the Late Preclassic period in the Northern Mesoamerican Frontier

The Northern Mesoamerican Frontier was a complex multicultural region characterized by frequent human settlement changes and shifts in agricultural conditions during the Late Preclassic period (~400 BCE-150 CE). Here, we report a high-resolution paleoenvironmental record from the varved sedimentary sequence of the crater maar La Alberca which spans the Late Preclassic (~400 BCE-150 CE) to part of the Early Classic period (~150 CE-250 CE) corresponding to Late Chupicuaro phase (400 BCE-100 CE) and Mixtlan phase (0–250 CE). Our work aims to study the paleoenvironmental conditions during the rise of agriculture in the Northern Mesoamerican Frontier and provide insights related to landscape alteration by human activity. To reach these aims, a multiproxy investigation was conducted by means of varve counting, high-resolution XRF scans, magnetic susceptibility, pollen data and fecal stanol biomarkers as a proxy for human population change. Our results reveal two varve type. Type 1 is characterized by the alternation of detrital-organic layers and aragonite layers, type 2 by alternating detrital-organic layers with an organic layer formed by diatom frustules and aragonite layers. This study suggest that the increase of erosion by human activity during the Late Chupicuaro phase (400 BCE-100 CE) and the start of the Mixtlan phase (0–250 CE) coincide with a high percentage of Amaranthaceae pollen, a rise of sedimentation rates, increase in nutrient content and the increase of human waste flux interpreted with the (Coprostanol + epi) :((Coprostanol + epi)+cholestanol biomarker. Moreover, a wetter period (~137 BCE-37 CE) interpreted during the Late Chupiacuaro phase and the start of the Mixtlan phase could suggest favorable environmental conditions for the establishment of agriculture.

The effect of prolonged irregular search and rescue operations on the hematological blood parameters of service dogs of medium breeds

The aim of the study was to assess the impact of prolonged irregular search and rescue operations on the hematological blood parameters of service dogs of medium breeds. The study was conducted on dogs of medium breeds: Border Collie, Australian Shepherd, Nova Scotia Retriever. The age of the animals ranged from four to ten years, and the body weight from 16.2 to 22.0 kg. Assessment of the condition of the animals before and after their participation in search and rescue operations was carried out based on the results of a clinical examination and a clinical blood test. A general blood test was performed on a Mindray BC-2800 Vet hematological analyzer. The following indicators were determined: the number of leukocytes; erythrocytes; hemoglobin level; erythrocyte sedimentation rate (ESR). The leukogram was derived from stained blood smears using an OLYMPUS CX23 Evidence immersion microscope. Based on the data obtained during the physical examination, there were no signs of any diseases, all the animals were clinically healthy. At the same time, the occurrence of obvious stress was noted in all. Blood sampling from animals was carried out after at least eight hours of a starvation diet, from the lateral subcutaneous vein of the thoracic limb, taking into account compliance with the rules of asepsis and antiseptics. It was found that the loads during prolonged irregular search and rescue operations have an impact on the clinical picture of the blood, expressed in a decrease in the average number of erythrocytes, hemoglobin, rod-shaped neutrophils, lymphocytes, and monocytes, as well as an increase in the number of leukocytes, eosinophils and neutrophils, as well as an increase in the rate of erythrocyte sedimentation.

Accumulation of thick fluvial sediments in the Shinano River incised-valley fills: implications for sequence stratigraphy and alluvial architecture

ABSTRACTThe relationship between fluvial systems and base-level changes, controlled mainly by sea-level fluctuations and tectonic activity, on time scales of 103–104 years, is important for evaluating and improving nonmarine sequence stratigraphy and numerical and physical alluvial architecture models. However, there are not enough quantitative data available from field studies, especially for periods of rapid base-level rise. The Echigo Plain, Japan, is a fluvial–coastal lowland where the tidal range is very small and where a very deep valley was incised by the Shinano River during the latest Pleistocene. The depth of the incised valley near the shoreline, 160 m below mean sea level, is greater than the amount of sea-level fall during the Last Glacial Maximum (LGM) because of tectonic subsidence. We studied an approximately 100-m-long borehole sediment core obtained from the landward part of the plain, where thick fluvial deposits have accumulated since the LGM. Sediment facies, diatom assemblages, sulfur content, carbon to sulfur ratios, and radiocarbon age dates indicate that most of the core sediments were deposited in a fluvial environment during the past 12 kyr. Sediment accumulation rates were 10–15 m/kyr between 12 and 8 cal kyr BP, and relatively low (less than 5 m/kyr) subsequently, mainly because of glacio-eustatic sea-level rise. The timing of the reduction in the accumulation rate is one possible indicator of the position of the maximum-flooding surface in a sequence composed only of fluvial sediments. The presence of many thin layers of very fine to fine-grained sand (20–80 cm thick), interpreted as crevasse-splay deposits, that formed between 11 and 8 cal kyr BP, when the base level was rising rapidly, implies that crevasse-splay deposits are characteristic of aggrading fluvial sediments and the transgressive systems tract in nonmarine sequence stratigraphy. Tectonic subsidence at approximately 2 m/kyr has contributed markedly to the larger accumulation rate of fluvial sediments of the highstand systems tract on the Echigo Plain, compared with rates in other fluvial–coastal lowlands, since 5–6 cal kyr BP, when the eustatic sea-level rise had mostly ceased.

Development of a machine learning model for river bed load

Abstract. Prediction of bed load sediment transport rates in rivers is a notoriously difficult problem due to inherent variability in river hydraulics and channel morphology. Machine learning (ML) offers a compelling approach to leverage the growing wealth of bed load transport observations towards the development of a data-driven predictive model. We present an artificial neural network (ANN) model for predicting bed load transport rates informed by 8117 measurements from 134 rivers. Inputs to the model were river discharge, flow width, bed slope, and four bed surface sediment sizes. A sensitivity analysis showed that all inputs to the ANN model contributed to a reasonable estimate of bed load flux. At individual sites, the ANN model was able to reproduce observed sediment rating curves with a variety of shapes without site-specific calibration. This ANN model has the potential to be broadly applied to predict bed load fluxes based on discharge and reach properties alone.

Suspended Sediment Transport in Mediterranean Streams: Monitoring and Load Estimation

The suspended sediment (SS) load provides valuable insights into soil loss magnitude, requiring comprehensive monitoring of streamflow (Q) and SS concentrations (SSC) across various hydrological conditions. The primary aim of this paper was to quantify SS loads in two mountainous river basins: the Carapelle (506 km2) and the Celone (72 km2) located in Apulia (Southeast Italy) where different monitoring strategies were adopted (i.e., continuous and discrete). The specific objective was to develop sediment rating curves to address gaps in the SSC time series. An optical probe was used to continuously monitor the SSC during 2007 to 2011 in a river section of the Carapelle river, while Q was measured with the ultrasonic method. A comprehensive dataset comprising continuous Q measurements and discrete SSC measurements was systematically acquired for the Celone river over the period of 2010 to 2011. Distinct sediment rating curves were formulated for three specific subsets of data delineated by discernible hydrological conditions (i.e., high, normal, and low flow) and SSCs were computed for the missing daily records. The annual specific sediment load exhibited a range of 2.4 to 6.06 t ha−1 yr−1 for the Celone river, while the Carapelle river displayed a range of 0.9 to 7.45 t ha−1 yr−1. A significant majority of the SS load was transported during high-flow conditions, accounting for over 80% of the total load. In contrast, during low-flow conditions, the SS load constituted less than 1% of the total load. The findings of this study highlight the significance of the hydrological regime as a critical factor influencing sediment transport in mountainous Mediterranean rivers. Furthermore, it demonstrates that the duration of the sampling period, along with its specific characteristics, such as dry or wet conditions, can have a substantial impact on the accurate quantification of the sediment load.

Astronomically forced cycles in Lower Carboniferous Luzhai Formation shales, Guizhong Depression, South China

Early Carboniferous Luzhai Formation developed continuous and thick shales, which is a critical succession for hydrocarbon exploration and production in southern China. However, no high-resolution stratigraphic sequence framework or cyclostratigraphic studies on early Carboniferous (Tournaisian Stage) are available for this organic-rich shale formation. In this research, Milankovitch cycle evidence has been reported in two boreholes of Luzhai Formation in Guizhong Depression. Natural gamma-ray logging data allowed the establishment of a ∼5.9-Myr floating astronomical timescale (FATS) based on stable long eccentricity (405-kyr) cycles in Luzhai Formation. We anchored FATS to Devonian and Carboniferous boundary age (359.3 ± 0.4 Ma), and an absolute timescale for intervals of 359.3 to 353.4 Ma was developed. Correlation coefficient (COCO), evolutionary COCO, and evolutionary TimeOpt method (eTimeOpt) were employed for quantitatively fit observed stratigraphic cycles to astronomical cycles for providing possible range of sedimentation rates. Sedimentary noise model was adopted for detecting orbital forcing-controlled high-resolution sea-level changes which were correlated to ∼1.2-Myr obliquity amplitude modulation (AM) cycles. Sedimentary noise models (autocorrelation coefficient analysis, ρ1, and dynamic noise after orbital tuning analysis, DYNOT) revealed a correlation between obliquity AM cycle (∼1.2-Myr) and sea level changes in early Carboniferous Luzhai Formation. The ∼1.2-Myr obliquity AM was the main driver of third-order sequence development, the 3rd-order sequence boundaries were related to maximum values of DYNOT median curve and minima values of ∼1.2-Myr amplitude modulation (AM) curve.

Studies on the Preparation and Shelf Life of Aloe Vera Juice

The study was carried out for the preparation of aloe vera juice. Four different formulations of juices were prepared. The products were analyzed for their storage studies, microbiological study and sensory evaluation. The storage studies were done at room temperature (28-30ºC) and refrigeration temperature (4-6 ºC) at 7-, 15-, 30- and 45-days interval. At room temperature it was observed that pH and TSS was increased, pH changed ranging at 0.12-0.23%. The acidity of the sample was decreased during with increasing this storage period. It was observed that vit-C degradation occurred in all sample at room temperature storage. The sample containing 35% water + 300 PPM KMS (sample B) lost highest amount of vit-C compare to others sample. All the samples preserved with KMS were found good in their color, flavor, sourness and sweetness but sedimentation was observed after 30 days of storage. The highest sedimentation was observed in the juice containing highest amount of aloe vera juice. The rate of sedimentation increased with increasing the storage period. At both storage conditions the fugal growth was visible after 30 days. The microbiological analysis after 45 day of storage period showed that the total viable count (Bacteria) was less in the sample containing 30% water + 200 PPM KMS (sample A) in comparison to another sample containing 35% water + 300 PPM KMS (sample B), 30% water + 300 PPM KMS (sample C) and 35% water + 200 PPM KMS (sample D). The sensory attributes of aloe vera juices were evaluated and found the sample A and sample C obtained highest color, flavor and overall acceptability.

Reservoirs as high-efficacy sentinels of regional atmospheric pollution and precipitation: magnetic and chemical evidence from a typical subtropical reservoir in South China.

While there is a general sense that reservoirs can act as sentinels of climate change, their efficacy has not been thoroughly analyzed. Here multiple-proxy analyses including 210Pb, grain size, heavy metals, magnetic parameters, and spheroidal carbonaceous particles (SCPs) were conducted for a sediment core from a typical subtropical reservoir in South China (Huangkeng Reservoir). 210Pb dating revealed that the core spans from ~ 1964 to 2019, with the sedimentary rate increasing during recent years. The sedimentary environment was mainly influenced by natural process (especially precipitation), along with the accumulation of Cr, Ni, Cu, V, As, Sb, and Co and most magnetic particles. However, four heave metals (Cd, Pb, Tl, and Zn) were found mainly from atmospheric deposition from industrial/agricultural activities in Huizhou City, which was also indicated by SCPs, S-ratio, and χARM/SIRM. According to temporal variation of SCPs, the atmospheric pollution history ofnearby city (Huizhou Cityas the most close one) from 1964 was reconstructed. The study shows that reservoir sediments, especially in areas with few or no natural lakes, are high-efficacy and high-resolution achieves for research on environmental evolution in the Anthropocene related to global change and intensifying human activities.

The effects of subsalt relief on gravity-driven salt tectonics: Results from analogue modelling

Gravity-driven salt-related deformation on passive margins is commonly interpreted as kinematically-linked domains of updip extension and downdip contraction with an intermediate, undeformed zone of translation. Our study uses analogue models to show how salt flow is affected by the subsalt geometry resulting in complex deformation and the alternation of extensional and contractional domains in space and time in translational salt provinces. In our work, the analogue models incorporate subsalt relief associated with half-graben and graben that are realistic geometries along passive margins and combine the effects of gravity spreading in which deformation is driven by differential sedimentary loading, and an early-stage of gravity gliding induced by basin tilt. This approach allows for analysis of how salt flow and overburden deformation are affected by: (1) smoothly dipping subsalt relief; (2) subsalt relief characterized by half-graben with a gently landward dipping extensional fault; (3) subsalt half-graben connected laterally with a distal symmetric graben. For each of these models, we evaluate: 1) the interplay between slipping deformation corresponding to gravity gliding, gravity spreading mechanisms, and subsalt geometry; 2) the spatial and temporal distribution of salt-related structural domains; and 3) the contrasting styles of salt tectonics for different subsalt geometries. In addition, some of the experiments have been repeated considering thicker salt and pre-kinematic overburden and different sedimentation rates. We show that the structures of the subsalt relief variably resist salt flow producing flow mismatch. This variable resistance controls the orientation of the extension and contraction supra-salt structures. Salt surplus and contraction occur over landward dipping base-salt ramps, and a zone of salt depletion and subsidence limited by extensional and contractional hinges occurs over the basinward dipping base-salt ramp. Variations in width and the dip of these base-salt ramps result in stronger flow mismatches and deformation complexity. We also discuss variations in salt flow profile in response to the gravitational forces that drive deformation, allowing a good first-order approximation of viscous salt flow at a regional scale that can be directly compared to examples from various salt-bearing continental margins, particularly the relatively less understood but extremely economically important distal domains of Brazil's Campos and Santos basins.