Dry Climatic Periods Research Articles

A formation record of modern Nitraria tangutorum nebkhas on the Ordos Plateau of northern China based on optically stimulated luminescence dating

Nebkhas, as special biologically mediated aeolian landforms, play an important role in indicating regional aeolian activities and aeolian environmental changes. The Ordos Plateau is located in arid and semiarid regions of northern China that have a wide distribution of Nitraria tangutorum nebkhas. There are few chronological records of nebkha formation, so the history of the formation and evolution of nebkhas in the plateau is still unclear. In addition, the optically stimulated luminescence (OSL) dating method, which has been widely used in the dating of Holocene aeolian sediments, has not yet been applied to the dating of nebkha sediments in the Ordos Plateau. In this study, OSL methods were used to discuss the formation age and relevant aeolian activities of Nitraria tangutorum nebkhas in the Ordos Plateau. The results demonstrated that (1) the coarse-grained quartz OSL signals of nebkha sediments were insensitive and thus were inapplicable by the single aliquot regenerative (SAR) protocol. (2) The luminescence characteristics of the K-feldspar fraction and internal checks of the post-infrared infrared-stimulated (pIRIR) dating indicated that the pIR50IR170 protocol with 200 °C of preheating was applicable for De determinations of nebkha sediments. (3) The residual doses of the pIRIR170 signals ranging from 0.02 to 0.14 Gy should be considered when calculating De values. (4) Bayesian age-depth models were used for the Nitraria tangutorum nebkha sedimentary sequences. The formation of nebkhas occurred during a relatively dry climate period accompanied by strong aeolian activity. That ∼0.38 ka was the main growth period of Nitraria tangutorum nebkhas. This study is the first report of the formation age of nebkhas of more than one hundred years in the region.

Effects of climate variability and/or land use dynamics on the hydrological balance of the Cavally river catchment at Toulepleu, West Africa

Abstract The study focuses on assessing the individual and combined impacts of climate variability and land use change on hydrological responses. The results indicate that the basin, urban area, cropland, degraded forest, and open forest shows an increasing trend, while gallery forest show a decreasing trend over the period 1992–2015. Climatic variability is marked by two climatic periods (a wet one from 1980 to 1996 and a dry one from 1997 to 2016) with a 35% decrease in rainfall. Regardless of the state of the landcover used, the simulated mean annual runoff decreases by 67.92% between the wet and dry climate periods. Changes in land use between 1992 and 2015 reduce mean annual runoff by 4.71%. Analysis of the joint effect of climatic and LU variation shows a 68.96% reduction in runoff. In this catchment, the joint impact has a clearly greater effect on runoff than the climatic impact, which is greater than that of human activities. There is a need for policymakers to prioritise sustainable land use practices and integrated water resource management strategies in the area to mitigate the combined effects of climate variability and anthropogenic activities, ensuring the long-term resilience of the ecosystem and water availability for local communities.

Sedimentary Characteristics and Depositional Model of the Paleogene Dawenkou Formation in Eastern China: Insights from the Huanggang Depression

The Huanggang depression in eastern China is a significant Cenozoic salt-bearing basin that formed during the alternating dry and wet climate periods from the Eocene to the Oligocene. Despite the economic importance of the Huanggang depression, its saliferous model remains controversial. To address this issue, we conducted comprehensive analyses of the sedimentology and elemental geochemistry on the YZR1 borehole core, which hosts a relatively complete sedimentary record of the Huanggang depression, consisting of five lithofacies’ assemblages. The combined lithofacies and geochemical ratios, including B/Ga, Sr/Ba, and V/(V + Ni), provide insights into the paleolake’s evolution in the Huanggang depression. Our analyses indicated that the paleolake underwent a transition from a freshwater lake to a brackish water/saline lake, subsequently transforming into a salt lake, reverting back to a brackish water/saline lake, and ultimately returning to its original state as a freshwater lake. These changes are reflected in the sedimentary record and inform the six stages of evolution of the paleolake of the Dawenkou Formation. We propose two metallogenic models to explain the accumulation of the thick halite (LA1) and thin halite layers (LA2), respectively. LA1 is primarily dominated by halite deposition, forming in an extremely shallow water environment under arid climate conditions. In contrast, LA2 records the alternating deposition of halite, anhydrite, and mudstone, and formed in a shallow water environment under arid to semi-arid climatic conditions. LA1 has a much drier climate and higher salinity than LA2. Our results suggest that the salt-forming period in the Huanggang depression occurred from the late Eocene to the early Oligocene. The halite in the Huanggang depression formed in a shallow water environment, providing the basis for the halite deposition model of the depression. This study sheds light on the formation mechanism of halite in the Paleogene in eastern China.

Assessment of long-term water demand for the Mgeni system using Water Evaluation and Planning (WEAP) model considering demographics and extended dry climate periods

The Mgeni System is recognised as the main source of water supply for the Durban and Pietermaritzburg region in South Africa. This area is regarded as the primary economic hub of KwaZulu-Natal Province, and this brings about a high level of demographic pressure, with potential water supply problems in the future. This study investigates the water resource situation in the Mgeni System and evaluates future supply and demand accounting based on the (Water Evaluation and Planning) WEAP software. WEAP was used to analyse the study area for the period 2009–2050 to assess the impacts of various scenarios on future water supply shortfalls. Four scenarios were used, which take into account changing population growth rates and extended dry climates. The study found that the catchment is relatively sensitive to changes in population growth and extended dry climates, and this will alter the water availability significantly, causing a water supply deficit. In response to the projected future water demands, one technique to overcome the unmet demand is by introducing water conservation and demand management (WC/DM) strategies to reduce the water losses and shortfall encountered. By implementing adequate measures, water losses can be reduced, preventing water scarcity and giving decision makers time to provide further solutions to water supply problems.

Hydrological sustainability of in-pit reclaimed oil sands landforms under climate change

Development of robust reclamation designs would require understanding the relative effects of climate change on the water budget of reclaimed Athabasca oil sands landforms (Alberta, Canada). A surplus water budget is critical to sustain pit lakes and periodically freshen localized surface water ponds within the closure landscape. In this study, four hypothetical future climate scenarios were developed from statistically downscaled RCP2.6 and RCP8.5 climate projections and used in a hydrological model to investigate the potential effects of climate change on the water budget of an in-pit reclaimed oil sands mine landform. The four scenarios allowed the assessment of climate change effects for endpoints that bracket a range of future climate conditions on the water balance of the landform. Surface water and groundwater flow and chloride transport were simulated for the 2024–2100 period using daily climate forcing and the results were compared with equivalent responses under historical climate (1944–2020). The results suggest that the hydrological behavior under historical and RCP2.6 scenarios is similar. The climatic water deficit (potential evapotranspiration exceeding precipitation) will rise significantly under the RCP8.5 scenario. However, the modeling suggests that the water budget of the landform will not be too different from the early 21st century prolonged dry climate period. The chloride released from the landform under the different projected and historical climate scenarios also remained similar. Although evapotranspiration increases and leads to relatively drier conditions, a modest increase in precipitation helps maintain a surplus water budget in most years. The results demonstrate that incorporating future climate projections into water balance analyses is crucial to understand the potential reductions in runoff depths.

Prehistoric and technogenic loads of Hg in raised and blanket peats from the lower Amur River basin, eastern Asia.

Prehistoric and modern records of Hg in peats from the lower Amur River basin, eastern Asia, were investigated. The Hg accumulation rates (AR) of two 14C-dated cores from Holocene raised and blanket peats were determined. The low and monotonous Hg AR values of the raised peats determined in the lower part of the core (mean 1.9 μg Hg per m2 per year) represent prehistoric Hg inputs from the atmosphere. A sharp increase in Hg AR was determined upward of 52 cm depths (∼1600 year BP) (max 17.0 Hg μg per m2 per year), which apparently reflects the modern increase in global Hg emissions. The Hg loads in the blanket peats were apparently defined by a combined input from the atmosphere and the watershed followed by diagenetic redistribution. One major peak (max 12.0 μg Hg per m2 per year) coincided with increased Corg contents in herbaceous and sphagnum peat formed in the warming and wet climate of the early Holocene. Another peak (11.8 μg Hg per m2 per year) correlated both with the accumulation of Fe/Mn compounds and the warm and wet climate of the Holocene Climate Optimum. Minima Hg AR values coincided with the weakening of the East Asia Monsoon and cold and dry climate periods. In the uppermost layers, the Hg AR increased again up to 7.3 μg Hg per m2 per year, most likely due to anthropogenic pollution.

Groundwater Modeling with Process-Based and Data-Driven Approaches in the Context of Climate Change

In the context of climate change, the correct management of groundwater, which is strategic for meeting water needs, becomes essential. Groundwater modeling is particularly crucial for the sustainable and efficient management of groundwater. This manuscript provides different types of modeling according to data availability and features of three porous aquifer systems in Italy (Empoli, Magra, and Brenta systems). The models calibrated on robust time series enabled the performing of forecast simulations capable of representing the quantitative and qualitative response to expected climate regimes. For the Empoli aquifer, the process-based models highlighted the system’s ability to mitigate the effects of dry climate conditions thanks to its storage capability. The data-driven models concerning the Brenta foothill aquifer pointed out the high sensitivity of the system to climate extremes, thus suggesting the need for specific water management actions. The integrated data-driven/process-based approach developed for the Magra Valley aquifer remarked that the water quantity and quality effects are tied to certain boundary conditions over dry climate periods. This work shows that, for groundwater modeling, the choice of the suitable approach is mandatory, and it mainly depends on the specific aquifer features that result in different ways to be sensitive to climate. This manuscript also provides a novel outcome involving the integrated approach wherein it is a very efficient tool for forecasting modeling when boundary conditions, which significantly affect the behavior of such systems, are subjected to evolve under expected climate scenarios.

Dynamics of paleo-fires in the forest-steppe zone of the Western Siberia

Abstract. In this work we present the results of reconstruction of the dynamics of paleo-fires over the last 3300 cal. yr BP in the Barabinsk forest-steppe of the Western Siberia based on macrocharcoal analysis and radiocarbon dating of peat deposits of the Nikolaevsky ryam. The authors identified 18 local fire episodes using the CharAnalysis program. At the end of the Subboreal period, 6 local fires occurred, probably caused by dry and cold conditions. In the subAtlantic period of the Holocene, 12 fires were recorded with a peak of pyrogenic activity at 1200-1000 cal. yr BP. This peak of fires is probably associated with the warm and dry conditions of the Medieval Climate Optimum. As a result of the study, it was concluded that the intensity and frequency of paleo-fires in the area of Nikolaevsky ryam were influenced by climatic changes: in dry climatic periods, an increase in fire activity was observed.

Social Context of Late Medieval and Early Modern Deforestation Periods in the Apuseni Mountains (Romania) based on an Integrated Evaluation of Historical and Paleobotanical Records

ABSTRACT Coeval changes in the reconstructed bog surface wetness and the pollen record of a peat sequence extracted from an ombrothropic bog (Calul de Piatră, 1630 m, Apuseni Mountains) allowed the natural and anthropogenic environmental changes over the past 1500 years to be assessed. The assessment of the social and economic context was also possible due to the exceptionally detailed documentary evidence of the investigated region. Four major deforestation periods in the past 1500 years were identified. Significant phases of deforestation coincided with particular social and political changes: (1) between AD 810 and 850, with the collapse of the Avar Khaganate and the expansion of the Bulgarian Empire in the southern areas of the Carpathian Basin; (2) between AD 1060 and 1170, with the establishment of the Kingdom of Hungary (AD 1000) and the foundation of royal, territorial administrative (county) and ecclesiastical centres of the feudal state; (3) in the sixteenth century (AD 1500–1570); and (4) after AD 1700, with population growth and economic development. Our results suggest that the observed deforestation and the consequent spread of subalpine farming were not necessarily related to the warmer or drier climatic periods, but to socioeconomic changes in nearby communities.

Connectivity and flow regime direct conservation priorities for pelagophil fishes

Abstract Dam construction threatens global aquatic biodiversity by fragmenting stream networks and altering flow regimes. The negative effects of dams are exacerbated by increased drought periods and associated water withdrawals, especially in semi‐arid regions. Stream fishes are particularly threatened owing to their mobile nature and requirement for multiple habitats to complete their life cycles. An understanding of relationships with fragmentation and flow regimes, particularly as coarse‐scale (e.g. catchment) constraints on species distributions, is essential for stream fish conservation strategies. Prairie chub (Macrhybopsis australis) is a small‐bodied minnow (Cyprinidae) with poorly understood ecology endemic to the North American Great Plains. Suspected declines in abundance and extirpations have resulted in conservation interest for prairie chub at state and federal levels. Prairie chub is thought to share its reproductive strategy with pelagic‐broadcast spawning minnows (pelagophils). Freshwater pelagic‐broadcast spawning fishes have been disproportionately affected by fragmentation and streamflow alteration globally. Relationships of prairie chub occurrence with coarse‐scale fragmentation and streamflow metrics were examined in the upper Red River catchment. Occurrence probability was modelled using existing survey data, while accounting for variable detection. The modelled relationships were used to project the distribution of prairie chub in both a wet and dry climatic period. The probability of prairie chub occurrence was essentially zero at sites with higher densities of upstream dams, but increased sharply with increases in flow magnitude, downstream open mainstem, and flood duration. The projected distribution of prairie chub was broader than indicated by naïve occurrence, but similar in both climatic periods. The occurrence relationships are consistent with the hypotheses of pelagic broadcast spawning and represent coarse‐scale constraints that are useful for identifying areas of the stream network with higher potential for finer‐scale prairie chub conservation and recovery efforts. In addition to informing pelagophil conservation, the relationships are also applicable to pelagic‐broadcast spawning fishes in marine environments.

Vegetation record of the last three millennia in central Anatolia: Archaeological and palaeoclimatic insights from Mogan Lake (Ankara, Turkey)

In this study, the high-resolution palynological data derived from two cores taken from Mogan Lake in the Gölbaşı Basin of the Ankara region in central Anatolia (Turkey) are presented. The results provide the palaeobotanical, palaeoclimatological and palaeoenvironmental records of the last ca. 3100 years for the region which is characterised by rich natural resources and a long human occupation history. The major climatic events and the archaeological-historical periods, which are well established in previous works, along with textual sources, are related to vegetation history inferred from the palynological investigation in the study area. Five main vegetation phases are distinguished and interpreted. Our findings demonstrate that the phases of limited woody vegetation cover are chiefly coupled to several dry climate periods, with some exceptions. Steppe vegetation in an open landscape accompanied by more cultural indicators and lesser arboreal elements is inferred during the Near-East Aridification Phase at the LBA–Iron Age transition (c. 1200–850 BCE), Roman Warm Period before 700 CE, Medieval Warm Period at about 1020 CE, the 1500s and twentieth century. Only during the three dry episodes in the 1600s, 1800s and at the start of Modern Warming Period (in the twentieth century) partial arboreal recovery is deduced, and land-cover patterns are related to both natural and human-induced factors. The most extensive pine-dominated forest cover coincides mainly with the three wet climatic episodes, in Galatians times of the Hellenistic Period at c. 2080 BP, the 700s CE of the middle Byzantine era, the Seljuqs Dynasty and the earlier Ottoman Periods (c. 1165–1432/1435 CE). The former episode is represented by remarkable signs of human interference, while the others have marks of sporadically less cultivated landscape. It is concluded that a combination of various factors can be taken into account as the drivers of vegetation changes in the Ankara region, but climate appears to have been the primary agent in shaping the land-cover.

Dry and Wet Climate Periods over Eastern South America: Identification and Characterization through the SPEI Index

A large part of the population and the economic activities of South America are located in eastern regions of the continent, where extreme climate events are a recurrent phenomenon. This study identifies and characterizes the dry and wet climate periods at domain-scale occurring over the eastern South America (ESA) during 1980–2018 through the multi-scalar Standardized Precipitation–Evapotranspiration Index (SPEI). For this study, the spatial extent of ESA was defined according to a Lagrangian approach for moisture analysis. It consists of the major continental sink of the moisture transported from the South Atlantic Ocean throughout the year, comprising the Amazonia, central Brazil, and the southeastern continental areas. The SPEI for 1, 3, 6, and 12 months of accumulation was calculated using monthly precipitation and potential evapotranspiration time series averaged on ESA. The analysis of the climate periods followed two different approaches: classification of the monthly SPEI values as mild, moderate, severe, and extreme; the computation of the events and their respective parameters (duration, severity, intensity, and peak). The results indicate that wet periods prevailed in the 1990s and 2000s, while dry conditions predominated in the 2010s, when the longest and more severe dry events have been identified at the four scales.

Validation of a Predictive Fire Risk Indication Model using Cloud-based Weather Data Services

Abstract The high and dense representation of wooden homes in Norway, combined with periods of dry and cold climate during the winter season resulting in very dry indoor conditions, have historically resulted in severe fires. Thus, it is important to have an accurate estimate of the current and near future fire risk to take proper planning precautions. Cloud computing services providing access to weather data in the form of measurements and forecasts combined with recent developments in fire risk modelling may enable smart and fine-grained fire risk predication services. The main contribution of this study is implementation and experimental validation of a predictive fire risk indication model, which exploits cloud-provided measurements from weather stations and weather forecasts to predict the current and future fire risk for wooden homes at a given geographical location. The basic idea of the model is to estimate the indoor climate using measured and forecasted outdoor climate for computing indoor wooden fuel moisture content and an estimated time to flashover as indication of the fire risk. The model implementation was integrated into a micro-service based software system and experimentally validated during one winter at selected geographical locations, relying on weather data provided by the RESTful API of the Norwegian Meteorological Institute. Additionally, weather data from several historical fires were considered to relate our predictions to known fire incidents. Our evaluation demonstrates the ability to provide trustworthy and accurate fire risk indications using a combination of weather data measurements and forecast data. Furthermore, our cloud-and micro-service based software system implementation is efficient with respect to data storage and computation time.

The geoglyph sites of Acre, Brazil: 10 000-year-old land-use practices and climate change in Amazonia

Hypotheses concerning climatic change during the Amazonian Holocene often assume that the presence of ancient charcoal from forest fires indicates periods of drier climate in the past. These theories, however, neglect the possibility that such charcoal may result from early human activity. This article presents new evidence of anthropogenic ash and charcoal accumulation in the state of Acre, Brazil, dating back toc. 10 000 cal BP, which questions the value of charcoal as a proxy for phases of natural climate aridification. Carbon isotope (δ13C) values also suggest no significant changes in Holocene climate or vegetation. If these results are confirmed, previous studies on Amazonian Holocene climate will require re-evaluation.

Sequence stratigraphic analysis of thick coal seams in paralic environments – A case study from the Early Permian Shanxi Formation in the Anhe coalfield, Henan Province, North China

To study the possible role of base-level oscillations in the formation of thick coal seams in coastal plain (paralic) environments, the Early Permian Shanxi Formation No.21 thick coal seam was investigated in 3 cores spanning a distance of 29 km in the Anhe (Anyang-Hebi) coalfield, Henan Province using sedimentology, sequence stratigraphy, and coal petrology. The accommodation condition and origin of the peatland can be interpreted from maceral and mineral composition in the No.21 coal seam. Coals that accumulated in a low accommodation peat of ombrotrophic origin are characterized by relatively high inertinite content and relatively low mineral matter abundance. Coals accumulated in a balanced accommodation peat of rheotrophic origin are characterized by high vitrinite content and low abundances of inertinite and mineral matter. Coals with relatively high vitrinite content and relatively low inertinite content are interpreted to have accumulated in a high accommodation peat of rheotrophic origin. The No.21 coal seam was developed as part of a transgressive systems tract (TST) and displays maximum thickness in the central Anhe coalfield due to the local rapid subsidence of the formative delta plain. Six types of key stratigraphic surfaces are recognized in the coal seam, including terrestrialization (TeS), paludification (PaS), give-up transgressive (GUTS), accommodation-reversal (ARS), exposure (ES), and flooding (FS) surfaces. The No.21 coal seam consists of at least three drying-up and wetting-up cycles defined by these surfaces, with each cycle spanning from 20 ka to 30 ka. The variation of peatland type from rheotrophic through ombrotrophic and back to rheotrophic peat in the landward area implies the role of high-frequency climatic fluctuations, and the water level changes in the central and seaward areas may reflect sea-level fluctuations due to the hydrological connection to the sea and the change in rainfall to evaporation rates. These cycles arrived at a period close to that of climatic precession for Milankovitch cycles during the early Permian. The oscillating high and low summer insolation would have caused the alternating wet and dry climate periods that were then recorded as the wet-dry cycles in the coal seams. The results of this study can provide insights for research addressing hydrological conditions in ancient peatlands, and paleoclimate and sea-level fluctuations recorded in thick paralic coal seams.

Holocene palaeoenvironmental records from the high-altitude Wular Lake, Western Himalayas

We present a comprehensive record of Holocene (11,590–628 cal. yr BP) climate and hydrographic changes around the Wular Lake located in Kashmir Valley, India. Based on the multi-proxy investigations, we have identified three phases of wet climate conditions that prevailed from the commencement of the Holocene Epoch – 9000 cal. yr BP, 8100–6650 cal. yr BP and 6350–5000 cal. yr BP, whereas periods of dry climate were observed during 9000–8100 cal. yr BP, 6650–6350 cal. yr BP and ~5000 to 4000 cal. yr BP. The results also suggested that the lake widened and deepened significantly around 6350–5000 cal. yr BP. The results indicated desiccation and the exposure of the lake margin around 5000–4500 cal. yr BP. The sedimentation rate since 4500–628 cal. yr BP was quite low for detailed paleoclimate interpretations. Oscillations in lake extension and deepening appear to be due to changing intensity of westerly moisture in the region, and we correlate several of the low lake-level phases to the Bond events caused by North Atlantic ice rafting events.

Correlation between ocular sun exposure and pterygium: A hospital-based study

Background: The term “pterygium” comes from the Greek word “Pterygos,” which means “wing.” The major predisposing factors are the hot and dry climate and long periods of ultraviolet light exposure. Epidemiological studies have revealed that the prevalence of pterygium is inversely related to latitude, and that it is greater among outdoor workers than indoor workers. Although sun exposure has been accepted as a risk factor for pterygium, there is no objective diagnostic tool to measure the total amount of sun exposure of an individual. Materials and Methods: This is a prospective study carried out for a period of 1 year on 100 eyes with pterygium. Demographic variables including age, sex, residence, education, income, smoking, alcohol drinking, exercise, and especially sun exposure were collected from interviewing the patients as per the pro forma. Their occupation was categorized according to the fields of profession. A detailed eye examination which included slit-lamp examination, visual acuity, refractive status, and size of the pterygium was recorded. The size of the pterygium was measured in millimeters from its apex to the limbus using the slit-lamp beam. Pterygium was graded, depending on the extent of the corneal involvement, and all the patients were divided into five grades (Grades I to V). Results: Out of 100 pterygia, 89' were located nasally, whereas only 11' were temporal. Nearly 84' of the total pterygia were found in unilateral eyes, whereas only 16' were seen in bilateral eyes. The male-to-female ratio was 1.8' (65 males: 35 females). Nearly 35' of the pterygia were seen in middle-aged males (41–60 years), followed by 20' in 21–40 years' age group. Grade III pterygium was seen in 15' of male patients in 41–60 years' age group, whereas only 8' were seen in the same age group in females. Maximum number of patients having pterygium 10' (Group B) and 15' (Group C) showed a maximum duration of daylight exposure of 8 and 10 h, respectively. Conclusion: This study shows that outdoor work and sunlight exposure are positively associated with the development of pterygium. Besides sun exposure, other factors which favor pterygium formation such as dusty environment, smoking, and genetics should also be taken into consideration, and further research should be done to ascertain their role in pterygium formation. Public education should focus on encouraging people to take appropriate protective measures, such as wearing sunglasses and brimmed hats when outdoors, and to avoid unnecessary sunlight exposure.

Evaluation of strawberry varieties by biochemical composition and commercial qualities under the conditions of Orenburg Urals

The article presents the results of studies of the chemical composition, commercial qualities and taste of berries of promising strawberry varieties breeding of the All-Russian Horticultural Institute for Breeding, Agrotechnology and Nursery (Moscow) in the conditions of the Orenburg Urals. The studies were carried out in 2016-2018 on the basis of the Orenburg Experimental Station of Horticulture and Viticulture of the All-Russian Horticultural Institute for Breeding, Agrotechnology and Nursery in specific conditions, where almost annually dry and moderately dry climatic periods were observed during the formation of the yield (May-June). A comparative evaluation of varieties on the content of sugars, acids, vitamin C in berries, taste and attractiveness of appearance is given. The dependence of the studied parameters on the genotype of the variety and vegetation conditions was established. Depending on the variety and year, the content of soluble solids varied from 7.2 to 10.2 %, with an average content of 8.9 %; total acidity varied from 0.8 to 1.2 %, with an average content of 1.0 %; the content of ascorbic acid (vitamin C) was from 45.1 to 78.5 mg/100 g, with an average content of 56.4 mg/100 g. Varieties with high parameters of tasting evaluation (Darenka, Kokinskaya Zarya, Studencheskaya), soluble solids (Rosinka, Studencheskaya) and ascorbic acid (Kokinskaya Zarya, Bereginya) were revealed. They are recommended to be grown to obtain fresh consumption products and as processing products of various directions. Bereginya, Darenka and Rosinka varieties surpass control varieties in certain biochemical parameters and can be used in breeding in the Urals region to obtain new genotypes with an increased content of a specific biologically active substance. The variety Tsaritsa is selected for high commodity qualities of berries (weight, dessert taste, attractiveness of appearance) and is recommended for commercial production of berries and involvement in breeding process. It has been established that the taste of berries is determined by a complex of acids, sugars and aromatic substances. This parameter was greatly influenced by weather conditions, from which air temperature and precipitations were determining.

A Comparative Analysis of Phytovolume Estimation Methods Based on UAV-Photogrammetry and Multispectral Imagery in a Mediterranean Forest

Management and control operations are crucial for preventing forest fires, especially in Mediterranean forest areas with dry climatic periods. One of them is prescribed fires, in which the biomass fuel present in the controlled plot area must be accurately estimated. The most used methods for estimating biomass are time-consuming and demand too much manpower. Unmanned aerial vehicles (UAVs) carrying multispectral sensors can be used to carry out accurate indirect measurements of terrain and vegetation morphology and their radiometric characteristics. Based on the UAV-photogrammetric project products, four estimators of phytovolume were compared in a Mediterranean forest area, all obtained using the difference between a digital surface model (DSM) and a digital terrain model (DTM). The DSM was derived from a UAV-photogrammetric project based on the structure from a motion algorithm. Four different methods for obtaining a DTM were used based on an unclassified dense point cloud produced through a UAV-photogrammetric project (FFU), an unsupervised classified dense point cloud (FFC), a multispectral vegetation index (FMI), and a cloth simulation filter (FCS). Qualitative and quantitative comparisons determined the ability of the phytovolume estimators for vegetation detection and occupied volume. The results show that there are no significant differences in surface vegetation detection between all the pairwise possible comparisons of the four estimators at a 95% confidence level, but FMI presented the best kappa value (0.678) in an error matrix analysis with reference data obtained from photointerpretation and supervised classification. Concerning the accuracy of phytovolume estimation, only FFU and FFC presented differences higher than two standard deviations in a pairwise comparison, and FMI presented the best RMSE (12.3 m) when the estimators were compared to 768 observed data points grouped in four 500 m2 sample plots. The FMI was the best phytovolume estimator of the four compared for low vegetation height in a Mediterranean forest. The use of FMI based on UAV data provides accurate phytovolume estimations that can be applied on several environment management activities, including wildfire prevention. Multitemporal phytovolume estimations based on FMI could help to model the forest resources evolution in a very realistic way.

Variability in Shelf Sedimentation in Response to Fluvial Sediment Supply and Coastal Erosion Over the Past 1,000 Years in Monterey Bay, CA, United States

Continental shelf environments are uniquely situated to capture some of the most dynamic processes on Earth including climatic variability and anthropogenic modifications to coastal systems. Understanding how these processes have affected sediment delivery and accumulation on the shelf in the past may provide insight into potential changes in the future. To address this, we investigated shelf sedimentation within Monterey Bay, California. Sediment cores were collected from four locations throughout the bay to capture both the modern and late Holocene sedimentological record using grain size analysis, and sediment chronologies determined from 210Pb, 137Cs, and 14C. From the grain size results we focused on the total percent sand, and established a Littoral Sand Fraction (LSF) index to assess sediment contribution from the littoral zone as a result coastal erosion. Grain size results from the multicores consistently showed an increase in sand over the past several decades (post 1970s). For the cores located within the bay proximal to three major rivers, the increase in sand corresponded to a general increase in the LSF over the same period. We attributed these trends to increased sediment contributions to the shelf due to accelerated coastal erosion in the region. This accelerated coastal erosion was likely the combined result of dam construction in the mid-twentieth century that limited fluvial supply to the coast, and a shift in climate toward wetter, stormier period. Applying these sediment characteristics back over the past ~1,000 years we found that dry climatic periods resulted in deposits that were limited in total sand but enriched in littoral material suggesting elevated coastal erosion. During wet periods deposits were enriched in total sand but limited in littoral sand suggesting elevated fluvial supply and low erosion. Compared to the late Holocene record, the previous several decades represent a shift to a new regime, uncharacteristic of deposits over the past millennia, highlighting the impact humans have had on shelf sedimentation.