Estimates Of Sedimentation Rates Research Articles

Land conservation based on erosion and sedimentation rate (case study of Genting Watershed Ponorogo Regency)

The Genting Watershed is located in Ponorogo Regency, East Java Province. Population growth in the Genting Watershed causes changes in land use. Analysis of erosion and sediment control with the directive of land conservation in the Genting Watershed is needed to minimize problems like erosion and sedimentation in the Genting Watershed. Estimation of erosion and sedimentation rates was calculated with the AVSWAT 2000 model. The results show surface runoff equal to 94.437 mm/year, and erosion amounted to 49.189 tons/ha/year, and sedimentation equal to 6525.440 tons/year. From the results of calculations that have been made, Genting Watershed has five categories of erosion hazard level, among others the very light erosion hazard level equal to 43.346%, light amounted to 36,773%, moderate equal to 5,859%. Heavy amounted to 10,638% and very heavy equal to 3,384% toward the area of the Genting Watershed. To control the level of erosion hazard conducted an effort of conservation vegetatively by changing the land coverage of plantations/fields/shrubs planted with complex plants to reduce erosion by 21.634% and mechanically conducted by the making of check dam which can reduce sediment by 16.67%.

A comment about "A sedimentary record from the Makarov Basin, Arctic Ocean, reveals changing middle to Late Pleistocene glaciation patterns" (Quat. Sci. Rev., 270 (2021), p. 107176) from W. Xiao, L. Polyak, R. Wang, C. Not, L. Dong, Y. Liu, T. Ma, T. Zhang

Xiao et al. (2021) propose a climatostratigraphy of the Arctic Ocean built from a Mn-based cyclostratigraphy of deep sediments tuned to stack marine isotope stratigraphy that was proposed by Jakobsson and others in 2000. This cyclostratigraphy led to infer relatively high sedimentation rates in the central Arctic Ocean during the last glacial/interglacial cycles. It however required a reinterpretation of the magnetostratigraphy by inferring long-duration reversals during the Brunhes epoch. It also bypassed chronological constraints from U-series isotopes data. More recent papers based notably on the decay of U-series isotopes in sedimentary sequences, invalidate the chronology of the Mn-based cyclostratigraphy but confirm earlier works. This revised chronostratigraphy, in accordance with that of pre-2000 papers, points to much lower sedimentation rate estimates. It leads to drastically distinct climatostratigraphic inferences, as illustrated in the present comment from a tentative re-interpretation of the Xiao et al.’s data.

Potential Role of circRNA-HIPK3/microRNA-124a Crosstalk in the Pathogenesis of Rheumatoid Arthritis.

Circular RNA-HIPK3 (CircHIPK3) has been shown to be aberrantly expressed in a variety of diseases, contributing to disease initiation and progression. The aim of the present study is to investigate the role of the circHIPK3 RNA/microRNA-124a interaction in the pathogenesis of rheumatoid arthritis (RA). This study included 79 RA patients and 30 control individuals. The patients involved were classified according to the disease activity score (DAS28) into mild (24 patients), moderate (24 patients), and severe (31 patients). Serum samples were collected to estimate the relative gene expression of circHIPK3 RNA and its target gene microRNA-124a by quantitative real time-PCR. Moreover, ELISA was used to detect the serum levels of monocyte chemoattractant protein-1 (MCP-1). Routine laboratory estimation of erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and rheumatoid factor (RF) was also done. In all grades of RA groups, there was a significantly substantial elevation of circHIPK3 RNA gene expression, with subsequent downregulation of miRNA-124a when compared to the control group. CircHIPK3 and microRNA-124a expression have been established to be inversely linked. Also, estimation of serum levels of MCP-1, ESR, CRP, and RF exhibited a significant increase in all grades of RA as compared to the control group. CircHIPK3 and microRNA-124a might be regarded as key players in the pathogenesis of RA. The cross-talk between them appears to be responsible for inducing joint inflammation by increasing MCP-1 production. Targeting circHIPK3 and microRNA-124a, and their downstream adaptor molecules, poses a new challenge for RA therapy.

Constraining nitrogen sources to a seagrass-dominated coastal embayment by using an isotope mass balance approach

Nitrogen (N) is often the key nutrient limiting primary production in coastal waters. Quantifying sources and sinks of N is therefore critical to understanding the factors that underpin the productivity of coastal ecosystems. Constraining nitrogen inputs can be difficult for some terms such as N fixation and marine exchange as a consequence of uncertainties associated with scaling and stochasticity. To help overcome these issues, we undertook a N budget incorporating an isotope and mass balance to constrain N sources in a large oligotrophic coastal embayment (Western Port, Australia). The total N input to Western Port was calculated to be 1400 Mg N year−1, which is remarkably consistent with previous estimates of sedimentation rates within the system. Catchment inputs, N fixation, marine sources and atmospheric deposition comprised 44, 28, 28 and 13% of N inputs respectively. Retention of marine-derived N equated to ~3 and ~10% of total N and NOx flushed through the system from the marine end-member. The relatively high contribution of N fixation compared with previous studies was most likely to be due to the high proportion of nutrient-limited intertidal sediments where N is mediated by seagrasses and sediment cyanobacteria.

Sedimentation Rate Estimation and Tracing Organic Carbon and Nutrients Sources in Sediment of Ha Long Bay (Vietnam)

The temporal variation of SR was attributed to anthropogenic causes whilst spatial variation of SR was attributed to the difference of sediment sources supplied to the Bay. Concentrations of nitrogen and phosphorus in sediment are correlated with each other (R2 = 0.86) implying the nutrients were from the same source.

Multiproxy characterization of sedimentary facies in a submarine sulphide mine tailings dumping site and their environmental significance: The study case of Portmán Bay (SE Spain)

Mining activities are essential to our society, but ore extraction and treatment produce waste that must be stored in safe places without harm to the environment. For a long time, seafloor disposal has been viewed as a cheap option with barely visible impacts. In Portmán Bay, SE of Spain, large amounts of tailings from open pit sulphide mining were discharged directly into the coastal sea over 33 years, thus forming a massive deposit that completely infilled the bay and expanded seawards over the inner continental shelf. Here we present the first multiproxy physicochemical characterization of the submarine tailings in Portmán Bay, mostly by using non-destructive techniques, also including pre-dumping and post-dumping sediments. Eight distinct sedimentary facies, grouped in four stratigraphic units, have been thus identified in a set of up to 4.3 m long gravity cores totalling more than 60 m. Geogenic and anthropogenic geochemical proxies consistently allow differentiating pre-dumping sediments from tailings. Potentially toxic metals if made bioavailable can reach high concentrations in units including or formed exclusively by tailings (i.e. up to 3455, 2755 and 1007 mg kg−1 for Pb, As, and Zn, respectively). Some physical properties, such as magnetic susceptibility, are particularly useful as the tailings are rich in Fe-bearing minerals (>30% Fe in some layers). Estimated sedimentation rates show a strong gradient from proximal to distal locations, with rates in excess of 50 cm yr−1 to less than 1 cm yr−1. We ultimately document the history of the transformation of Portmán Bay from an almost natural state to a new condition after a long period of massive dumping of mine tailings. Our study provides guidance to further assessments in a context where the diversity of marine environments impacted by the disposal of mine waste is expected to grow in the near future.

A USLE-based model with modified LS-factor combined with sediment delivery module for Alpine basins

Sedimentation in reservoirs constitutes a major issue worldwide, especially when hydropower, and hence profit, is involved. In this study, the sedimentation rates, due to soil erosion and sediment yields, are analyzed in the reservoir of the Rio di Pusteria hydropower dam, in South Tyrol (Italian Alps). The focus is on a five-year period, between two consecutive sediment flushing operations occurred in June 2014 and May 2019. Based on the difference between the pre- and post-flushing bathymetries, the five-year aggregated sediment yield was determined. The soil erosion from the basin surface and the sediment budget in the reservoir are calculated by means of a gridded Universal Soil Loss Equation (USLE), combined with a Sediment Delivery Ratio (SDR) module. The topographic factor is improved by the use of a fine-scale DEM and the slope length factor is adjusted to the Alpine terrain by means of a fitting threshold. The rainfall erosivity factor is determined in two different ways, one representing the precipitation regime of the study area and one the specific rainfall conditions of the study period. The two different applications result to calculated reservoir sedimentation rates of 439,279.2 tons and 589,520.5 tons with deviations from the measured value of 3.1% and −23.2%, respectively, while the sediment delivery ratio to the reservoir was found to be 12.5%. The calculations are also compared with results of the application of the conventional six-factor USLE. The comparison between calculations and measurements shows that the methods used can be efficiently applied in an Alpine basin for the estimation of reservoir sedimentation rates.

Estimation of Reservoir Capacity and Sedimentation Rate Using Direct and Indirect Methods

Dams are important in harnessing flood water to enhance water availability during the dry season. Globally, most dams no longer hold the amount of water they were designed to hold due to sedimentation. The study sought to monitor sedimentation of Chesa dam in Upper Ruya Subcatchment, Mazowe Catchment in Zimbabwe. Five Landsat 8 OLI datasets for the period 2015 to 2017 were used. Remotely sensed sedimentation data was analysed using the NDWI method. Results indicated that Chesa dam's current capacity was 374,535

Late-Holocene evolution of the Northern Bay of Cádiz from geomorphological, stratigraphic and archaeological data

The present paper deals with the historical evolution of the northern Bay of Cádiz (SW Spain) between the last eustatic maximum (6.5 ka BP) and the present day, by means of a series of independent proxies. The zone is constituted by the tidal estuary of the Guadalete River, filled with saltmarsh sediments during the late Holocene, due to the sheltering of the zone by a confining outer sandy barrier. The northern border of the Bay records an urban settlement of Phoenician Age (first millennium BC), Doña Blanca. A detailed survey was made in the contact between the Phoenician city and the saltmarshes in order to detect other possible urban structures related to the morphological and sedimentary evolution of this environment during historical times. Two campaigns with GPR Stream-X array were carried out as well as aerial imaging and topographic survey with UAV. In parallel, a total of 8 boreholes were made in different parts of the saltmarshes, including radiocarbon dating of selected samples for estimating sedimentation rates in the saltmarshes. Results obtained by georadar prospection and UAV survey revealed the presence of a second urban settlement on the marginal sedimentary plain, very probably installed upon a sandy fluvial island of the Guadelete River. The urban remains, of Punic Age, are partly covered by clay sediments due to the subsequent evolution of these saltmarshes, where sedimentation rates of up to nearly 2.4 mm/yr have been estimated for environments close to fluvial and/or tidal channels and hence more affected by sediment aggradation during flooding episodes. In recent times, river regulation by dams and the artificial desiccation and cropping of the saltmarshes have interrupted the natural trend of the area towards sedimentary silting up.

How dusty was the last glacial maximum over Europe?

Our study focuses on European loess sequences, particularly the eolian intervals in between the observed pedogenic units. The classical concept of soil formation from parent material is reformulated to estimate of the duration and the associated sedimentation rate (SR) and mass accumulation rate (MAR) of these paleodust intervals. We show that the Greenland Stadial (GS) duration in European loess deposits includes the thickness of the overlying pedogenic unit, which in fact developed downward into the upper part of the eolian unit. The lower stratigraphical limit of the eolian unit overlying the pedogenic unit corresponds to the restart of the dust sedimentation of the younger GS. We illustrate this interpretation first by computing both SRs and MARs first for the Nussloch key sequence, the most complete European series. The correlation between Nussloch and other European loess sequences, located along a 1800 km longitudinal transect, allows computation of SR and MAR for several identified GS events. Comparing GS from marine and ice core records, our study shows that the two last Bond cycles are preserved in every European eolian record.Bulk SR and MAR are estimated and compared for these two Bond cycles, showing the highest SRs and MARs in western Europe. These indices also indicate that the last stadials, embedding an Henrich event, were not the dustiest in every Bond cycle. Our estimated MAR also differ from previously published computations, which did not take into account the various pedogenic units present in the studied loess sequences. The bulk SR and MAR estimates computed for the two last Bond Cycles from Chinese sequences from the Loess Plateau indicate lower atmospheric dust than in Europe during the Last Glacial Maximum. SR and MAR estimates computed from the fine-grained material for European records fit with Earth System model reconstructions.

Toxicological Effect of Euphorbia heterophylla Linn

Euphorbia heterophylla has been reported to possess enormous medicinal benefits hence there is a need for holistic research on its toxicological effects. Four different solvents (cold and hot water, chloroform and 80% methanol) were used to extract the aerial parts of Euphorbia heterophylla Linn. Experimental albino rats were obtained from Federal University of Technology Akure’s Microbiology Department Animal House. Toxicological analysis of Euphorbia heterophylla extracts was carried out on the experimental albino rats. The animals were grouped into thirteen with three rats in a group different concentrations of the extracts were administered orally to different groups of the rats for a period of two weeks (14 days). Sterile distilled water was administered to the negative control group. During the 14 days of extracts administration, the animals were observed for clinical manifestations like salivation, nervousness, imitability, itching of the nose and diarrhoea. After the expiration of the two weeks, the animals were sacrificed and vital organs like heart, liver, kidney and intestine were harvested and examined for any degenerative changes and lesions. Blood samples were collected before and after the administration of the extracts to check for blood parameters (Packed Cell Volume (PCV), white blood cell count (total and differential), erythrocyte sedimentation rate (ESR) and haemoglobin (Hb) estimation. The toxicological results of the extracts showed various degrees of abnormalities detected in the histopathological sections of the intestine, kidney and the heart. It was found that all the extracts at different concentrations burnt the intestinal walls of all the animals tested. There were significant reductions in the total white blood cells (WBC) and neutrophil counts while there was a significant increase in the lymphocytes count after the administration of the extracts. The findings of this study revealed that Euphorbia heterophylla had toxicological effects on the albino rats organs but increases there lymphocytes count, boosting their immune system, however advance researches to eliminate the toxic phytochemicals from the extract is recommended.

Sedimentation rates in the Baltic Sea: A machine learning approach

Sedimentation rate data are applied in a range of studies such as understanding the sediment carbon budget and accumulation of pollutants in marine sediments. Over many years, sedimentation rate samples have been collected within the Baltic Sea. However, to understand patterns in sedimentation rates more broadly across this sea basin requires converting these point data into continuous spatial predictions. The generation of continuous maps remains problematic and under-studied. This study explores the feasibility of machine learning to estimate sedimentation rates, using 137Cs measurements from the Baltic Sea. A random forest model was applied to predict sedimentation rates based on a range of predictor variables that related to the hydrodynamic regime, bathymetric complexity of the seabed, substrate type and proximity to sediment sources. The accuracy of this prediction was tested against an independent set of sedimentation rate samples that had been withheld from model training. The model was also compared against a simple spatial interpolation to assess whether machine learning produces an improvement on previously applied methods. Overall, the modelling approach explained 41.9% of the variance, far surpassing the spatial interpolation method (4.2% variance explained). This study is a first step towards the spatial prediction of sediment accumulation rates in a repeatable and validated way, but further refinement is desirable to improve the accuracy of the predictions. We discuss the potential sources of model error that could have limited the success of this approach and suggest how some of these could be addressed. Our results indicate that short-term sedimentation rates are highest in small coastal basins, while rates in the deep basins of the Baltic Sea are generally low, thereby seemingly contradicting long held views of the deep-basins as the major depocentres in the Baltic Sea. This apparent contradiction might be attributed to the higher spatial detail of our analysis and differences in the time scales of analysis, indicating that sedimentation patterns in the Baltic Sea might be complex in space and time.

Whump, Slosh, Slosh, Slosh—Filling the Crater That Did in the Dinosaurs

AbstractDrilling into the Chicxulub crater (Yucatan, Mexico) reveals the dramatic aftermath of the dinosaur‐killing meteorite impact. Previous views of this event have mainly come from places well away from Ground Zero, where we see the extinction of ~70% of life, the fallout of a globe‐spanning ejecta cloud, and the slumps and tsunamis that accompanied one of the biggest terrestrial earthquakes ever. The new view from the crater in a drill core records the collapse of the shattered and melted crater walls, the flood of the ocean back into the submarine crater, and the formation of hot vents over the pool of melt rock. The record shows that decades to centuries after the impact, the calm tropical marine lake was taken over by red tides and animals that colonized the previously sterile crater floor. The exact timing of appearance of the first newly evolved species is hard to pin down but probably occurred within a few centuries to several millennia based on evidence from the intensity of burrowing and estimates of sedimentation rates.

Challenges to select suitable habitats and demonstrate ‘additionality’ in Blue Carbon projects: A seagrass case study

Seagrass restoration has been suggested as a Blue Carbon (BC) strategy for climate change mitigation. For Nationally Determined Contributions (NDC) and carbon crediting schemes, BC projects need to demonstrate ‘additionality’, that is enhanced CO2 sequestration and/or avoided greenhouse gas emissions following management actions. This typically requires determining soil carbon accumulation rates (CAR), which is often done using radionuclides or surface elevation tables to estimate sedimentation rates. Here we undertook a case study, using 210Pb and 14C dating, to detect possible changes in Corg stocks and CAR following the loss and partial recovery of Posidonia seagrass meadows in South Australia since 1980–90s. The 210Pb data revealed a lack of accumulation of excess 210Pb in most sites, suggesting negligible accumulation of sediments, intense mixing of the upper layers, or accumulation of reworked sediments, precluding the estimation of reliable CAR at decadal time scales. This limitation was also encountered with 14C. The inability to compare sites over analogous periods of time prevented quantifying differences in soil Corg sequestration, thereby to demonstrate additionality. The lack of significant differences in soil Corg stocks among sites which never suffered seagrass loss, those showing recovery and those with no recovery (5.7 ± 1.2, 4.5 ± 0.7 and 3.3 ± 0.3 kg Corg m-2 within the top meter, respectively) also precluded estimates of soil Corg gains or losses. Our findings demonstrate that, while 210Pb and 14C provide important information on sediment deposition dynamics, it is not straightforward to demonstrate additionality using radionuclides in low depositional seagrass habitats exposed to hydrodynamic energy, features which may be encountered in seagrass sites. We provide insights for the selection of suitable habitats for seagrass BC projects, suggest possible alternative methods for estimating additionality, and discuss the implications of the findings for the implementation of seagrass BC strategies to mitigate greenhouse gas emissions.

Assessment, typo error on Author's response of Post Ischemic Stroke Infections

BackgroundInfection is a common complication in acute phase after stroke, and even in specialized stroke units, it remains one of the major complications. The relationship between infections and acute ischemic stroke is complex and bidirectional. Infections can result in ischemic stroke, and the rate of infection is increased after ischemic stroke.Aim of workThe aim of this study is to estimate the incidence of post-stroke infections in the Egyptian patients, with determination of the most common infections, possible risk factors, and their clinical implications.MethodsThe study was conducted on one hundred adult patients with acute ischemic stroke, full medical history, thorough clinical examination, routine laboratory investigations, estimation of erythrocyte sedimentation rate and C-reactive protein, abdominal ultrasound, plain X-ray of the chest, culture and sensitivity, non-contrast computed tomography, magnetic resonance imaging for patients with normal CT studies of the brain, duplex study of both carotids and vertebral, ECG, and echocardiography, any further investigations needed and lastly collected data statistically analyzed.ResultsThe results of our study showed that 32 patients (32%) developed post-stroke infection. Post-stroke infections increased with higher age and female gender. Post-stroke infections were strongly correlated to the presence of atrial fibrillation, previous stroke, or transient ischemic attacks. The occurrence of post-stroke infection was significantly correlated to stroke severity, size of infarction, and carotid stenosis. Post-stroke infection was also correlated with the occurrence of multiple post-stroke neurological complications. Infections that occurred post-stroke were pneumonia (21%) and urinary tract infection (15%), blood (5%), and subcutaneous infection (3%).ConclusionStroke is a major health problem, and infection is one of the commonest post-stroke complications. Post-stroke infection significantly affects clinical outcome and being strongly associated with occurrence of neurological complications.: study was conducted on one hundred adult patients with acute ischemic stroke, full medical history, thorough clinical examination, routine laboratory investigations, estimation of erythrocyte sedimentation rate and C-reactive protein, abdominal ultrasound, plain X-ray of the chest, culture and sensitivity, non-contrast computed tomography (CT), magnetic resonance imaging (MRI) for patients with normal CT studies of the brain, duplex study of both carotids and vertebral, electrocardiography (ECG), and echocardiography, any further investigations needed and lastly collected data statistically analyzed.

Assessment of Sedimentation and Useful Life of Tehri Reservoir using Integrated Approaches of Hydrodynamic Modelling, Satellite Remote Sensing and Empirical Curves

The higher rate of sedimentation in reservoirs is one of the main concerns in sustainable reservoir management, which impairs the functional capacity of reservoirs that may lead to various environmental risks. Estimation of sedimentation rate and useful life of a reservoir using appropriate methods is imperative for sustainable management. This paper deals with the computation of sedimentation rate and useful life of Tehri reservoir of Bhagirathi river, in India, using hydrographic survey analysis, Hydrologic Engineering Center’s River Analysis System (HEC-RAS) modelling, satellite remote sensing (SRS) technique, and trap efficiency based empirical curve methods. The rate of sedimentation was found as 5.33 million cubic metres (MCM)/year based on hydrographic survey analysis from the data obtained for the years 2005, 2008 and 2013. Likewise, the mean annual rate of sedimentation was estimated to be 5.07 MCM/year and 5.75 MCM/year based on the HEC-RAS model and SRS techniques respectively. Brune’s method and Churchill’s method of trap efficiency were found to be inconsistent with the hydrographic survey results. The reservoir can be classified as Type III reservoir with respect to the sediment vertical distribution analysis. Changes in bathymetry obtained in the simulation studies showed that the Bhagirathi river’s 28–30 km reach would be most vulnerable to sedimentation problems. The estimated useful life of Tehri reservoir was found to be in the range of 160–180 years. The SRS technique and hydrodynamic model provided a better fit with the observed data.

Estimating sedimentation rates in small reservoirs - Suitable approaches for local municipalities in central Europe

Small reservoirs, as the preferred blue-green engineering infrastructure for use against intensive runoff processes, have risen in number in Central Europe during the past three decades. However, the modelling of sediment siltation is not included in reservoir planning. The unknown temporal sedimentation of a reservoir can lead to the lifespan of the construction being uncertain. The aim of this study is to present a relatively simple process for local managers to model siltation and, consequently, accurately estimate the lifetime of a small reservoir. Three empirical models (USLE, RUSLE and USPED) were applied to two small catchments in Central Europe. This paper takes advantage of real measured and modelled sedimentation during 2012 and 2017, presenting two different terrain measurement approaches. Our study emphasizes the importance of the R-factor value. The temporal development of the R-factor is dependent on climate change, and the R-factor value has been rising steadily during the last decades. The annual mean R-factor has increased 1.04-times due to changes in precipitation patterns between the periods 1961-1980 and 1997-2016. These changes can explain possible growth in the levels of incoming sediment into reservoirs. We identified the correlation (R>0.7) between observed sedimentation, the R-factor, and precipitation, and we concluded that the supposed rise of precipitation in Central Europe due to climate change will lead to an increase in the levels of stored sediment in reservoirs. Therefore, it is recommended for reservoir managers to use USPED model and to include the estimation of modelling of siltation rate into reservoirs' maintenance projects.

Soil and Environmental Conditions at the Oroshaemoe Neolithic–Eneolithic Archeological Site in the Lower Volga Region

The results of interdisciplinary research conducted at the Eneolithic archeological site Oroshaemoe (5–7 ka BC) in Saratov oblast are presented. The studied soils are calcareous light chestnut soils (Eutric Cambisols (Loamic, Protocalcic, Ochric)); in the archeological excavation, they are human-modified and contain various artifacts. A set of pedological, paleopedological, paleoclimatic, and paleobotanical methods and radiocarbon dating have been applied. Information on alternation of the periods of humidization and aridization of the territory, stages of soil formation and sedimentation, and on the vegetation cover in the Holocene at the archeological site has been obtained and refined. According to our data, periodic alternation of more humid and more arid conditions has taken place since 7245 ± 60 BP. The stages of aridization were accompanied by the short-term sedimentation related to the activation of eolian processes. Loesslike sediments deposited during these stages are archeologically sterile (do not contain artifacts) and are relatively thin in comparison with the cultural layers separating them. The stages of humidization were marked by more active sedimentation accompanied by soil formation. The obtained data suggest that the past 5000 years have been the period of some humidization of climatic conditions. Preliminary estimates of sedimentation and soil formation rates in the Holocene in the study area attest to their considerable fluctuations. Thus, the rate of soil formation varied from 35 to 0.8 cm per century. The results of this study allow us to refine paleoclimatic reconstructions for the considered area. Periodic changes in the environmental conditions during the Holocene affected the life of the tribes, patterns of human settling, and regional and, possibly, global migration processes. The reconstruction of natural and climatic features of the archeological site and its comparison with published data attest to the uneven paleogeographic situation in the Lower Volga region. It is argued that the chronology of landscape and climatic changes during the Holocene as presented in the publications for the southern arid regions of the East European Plain needs to be revised and made more detailed.

Estimation of sedimentation rates of single pollen grains and pollen clusters of anemophilic plants growing in CSBG SB RAS

Estimation of sedimentation rates of single pollen grains and pollen clusters of anemophilic plants growing in CSBG SB RAS

Sedimentation Patterns in Sorsogon Bay, Philippines Using 210Pb

210Pb has been used as a tracer to give an insight into the sedimentation process occurring in Sorsogon Bay. The sedimentation process can provide the possible sources, movement, pathways, and sinks of sediments and sediment-associated materials (e.g., chemicals, pollutants) – which are important for a better understanding of the changes happening in the bay and its watershed. The information that will be derived can be used as an input parameter by other researchers doing modeling work (material/water/pollutant flow, movement, dispersion, and residence time dynamics) at Sorsogon Bay. Seven sediment cores have been collected in Sorsogon Bay to determine the 210Pb-derived sedimentation rate estimates across the bay. A sedimentation rate of 1 cm/yr could be estimated for the eastern, central, and western areas of Sorsogon Bay. Areas near Sorsogon City (SO-07), Cadacan River (SO-03), and the area offshore of Buenavista and Rizal (SO-06) have enhanced sediment deposition, which could be due to an area where enhanced erosion from human activities is apparent, proximity to a river system that drains/carries volcanic material and debris from Mount Bulusan, and near an open dumpsite where possible materials (wastes, debris, leachates) could be carried offshore respectively. The sedimentation rates are shown to be higher in the shallower areas of the bay.