Trending Zone Research Articles

Assessing vegetation restoration potential under different land uses and climatic classes in northeast Iran

This study examines the trends in vegetation cover using the Growing Season NDVI (GSN) time series in moderate spatial resolution (250 m) over Khorasan Razavi province, in northeast Iran, during the period 2004–2015. The province is largely desert, with extra-arid, arid, and semi-arid de Martonne climate zones dominating, while rangelands, shrublands and deserts cover most areas, making it an ideal territory for monitoring vegetation trends and implement future restoration projects. Most parts of the province and land-cover classes show no trends in vegetation cover, but large decreasing trends occur in areas covered by sand dunes, previously reforested lands and clay pit areas. Trends in various land-cover types are also examined as functions of the climatic class and the Terrain Niche index (TNI), which is characteristic of the topography, revealing large decreasing trends in the extra-arid climatic zone. In addition, most of the areas exhibit Hurst exponent values around 0.5, implying stochastic time series without any consistency and a likelihood of random vegetation and land cover changes in the future. This study also aims to determine likely future vegetation status and the most favourable areas for restoration projects through analysis of two indexes (Future Restoration Dispersal Index, FRDI and Future Uncertainty Dispersal Index, FUDI). The results show that reforestation, sand dunes and clay pits areas are the most favourable for implementing restoration projects, while the spatial distribution of the potential restoration classes reveals that the southern and northeastern parts of Khorasan Razavi province are the most favourable areas for establishing environmental restoration activities in order to avoid further degradation of ecosystems.

Climate change trends in the forest-meadow zone of the Middle Urals and their impact on technological approaches to corn cultivation

The results of the analysis of long-term trends in changes in individual climatic characteristics and variations in weather conditions of the growing season in the forest-meadow zone of the Middle Urals for the period from 1958 to 2020 are presented, their influence on the choice of hybrids and some elements of corn cultivation technology are estimated. As a result of calculating the linear trend, a statistically proven trend has been established to increase the sum of active temperatures above 10 °C for May – September. At the same time, random fluctuations of the analyzed parameters over the years have a direct impact on corn development and productivity, and the limiting factor is the lower limit of these fluctuations, the values of which increase throughout the analyzed period. Nevertheless, the variation over the years remains strong, and the lower limit of these fluctuations does not reach the minimum level for the stable maturation of early-maturing corn hybrids. Therefore, for the conditions of the Middle Urals, the previous recommendations concerning the selection of corn hybrids for early maturity, cold resistance and drought resistance remain relevant. At the same time, the revealed climatic trend allows to predict an increase in the probability of obtaining feed with a high content of exchange energy, which characterizes it as positive one.

Признаки крипа в зоне влияния Зундукского разлома на северо-западном побережье озера Байкал

The results of a high-resolution aerial survey at selected areas in the Zunduk fault damage zone trending northeast along the coastline of the Maloe sea of Lake Baikal from Cape Yadyrtuj are presented. The research was carried out within the framework of the problem of studying the seismotectonics of the shores of Lake Baikal to map the youngest surface ruptures. Based on the images obtained using DJI «Phantom 4 Pro V 2.0» unmanned aerial systems (UAS), we generated orthomosaics and digital terrain models, interpretation of which allowed us to reveal recent ruptures in alluvial fans. The largest number of them is concentrated on the Oto-Khushun Cape, where the development of disturbances as feathering structures occurs at the intersection of the Zunduk fault trending NE–SW and a proposed fault trending NNW–SSE in the water area of Lake Baikal. It explains the block structure of the rupture network in the southwestern part of the cape. Ground penetrating radar profiling showed that the surface ruptures penetrate to a depth of at least several meters. Since the last rupturing earthquake in the Zunduk fault zone is supposed to have occurred 12000–14000 years ago, the ruptures mapped in recent sediments are the result of creep events. The mechanism of their formation is associated with the periodic effect of weak seismic loads on the granular medium, as a result of which micro-slip and subsequent growth of ruptures occur. Taking into account the high rates of erosion and sedimentation within the mountain alluvial fan, as well as the persistence of disturbances in recent sediments, it can be assumed that this process is relatively constant. Identification of such brittle deformations and monitoring of their development in river deltas and outflow cones of watercourses will make it possible to predict possible places of the collapse of the coastal areas of Lake Baikal during moderate and strong earthquakes, as well as to study the dynamics of coastal development – an important component of the abiotic part of the lake ecosystem

Analysis and interpretation of geophysical data to delineate the geologic structures of Abu Dabbab area, South Eastern Desert, Egypt

ABSTRACT The present study aims to identify the geologic structure of the Abu Dabbab area. The previous work state that the study area contains different ore minerals such as Tantalum, Niobium, Cassiterite, Gold, and sulphides. Processing, analysis, and interpretation of aeromagnetic and recorded seismic events data of the study area were to define the seismic activity zones and the main trend in the study area and its relation with ore deposits distribution. The area is controlled by different structural elements of trends NE-SW, NNW-SSE, and E-W. The results indicated that most of ore deposits are located at an active fault zone which is characterised by high seismic activity. There are high deformation zone trends NE-SW. There is a high value zone located approximately at the centre of the northern portion of the study area. This high energy zone is oriented towards NE and extends to the Red Sea. The energy map shows that the energy released from the study area is considered as a part of the energy release of the Red Sea area suggesting a tectonic connection between this region and the Red Sea.

A tectono-geomorphological perspective of micro-earthquake swarm activity prone areas around Bhavnagar and Jamnagar in Saurashtra, western India

Areas around Bhavnagar and Jamnagar in eastern and northern parts of Saurashtra respectively, are identified previously as prone to recurrent earthquake swarm activity. Sparse seismotectonic studies so far have not revealed any linkage with known faults in Bhavnagar area while no structures are known to occur in the area around Jamnagar. We carried out detailed tectono-geomorphic studies with contrasting geomorphic settings with a view to provide an insight into the swarm activity from a geomorphological perspective. The study is based on extensive field studies and quantitative geomorphic analysis of landscape and drainage. The area around Bhavnagar is divisible into two tectono-geomorphic domains – the E-W trending Sihor Fault zone located to the west of Bhavnagar (domain-I) and the terrain to its south which shows undulating landscape controlled by N–S trending structural trends (domain-II). The quadrant in the SW between these two domains consists of southward titled trappean hills which form source area for drainages flowing northward through Sihor Fault zone and those flowing eastward through domain-II. Late Quaternary, possibly Holocene tectonic activity along the Sihor Fault is indicated by the northward tilt of alluvial plain surface, knickpoint in rivers and small scale minor faults along the fault zone, prominent decrease in depth of fluvial incision away from the fault zone and youthful landscape indicated by drainage basin analysis. Domain-II comprises the largely erosional pediplain developed over trappean and Tertiary rocks to the south of Bhavnagar. The drainages show an early stage of landscape development due to ongoing tectonic activity. The area around Jamnagar is dominantly a peneplain formed over subhorizontal trappean lava flows. The peneplain is a manifestation of the prolonged period of non-erosion and deposition during the Cenozoic. The rivers show youthful landscape in the central part of the peneplain which includes, large knickpoints, rapids, anomalous river bends, steepening of channel gradient and large potholes. This ENE-WSW trending zone of anomalous fluvial geomorphic anomalies points to the existence of a fault or fold in the subsurface. The structure appears to be active as indicated by the denser cluster of earthquake swarm along this zone. We infer that the generation of earthquake swarm activity comprising low to moderate magnitude shocks is caused by the sheared rocks along the Sihor Fault near Bhavnagar and the ENE-WSW trending subsurface structure near Lalpur which provide avenues for downward percolation of rainwater to deeper levels causing loss of frictional resistance along weak planes.

Innovative Trend Analysis of Air Temperature and Precipitation in the Jinsha River Basin, China

Trend detection based on hydroclimatological time series is crucial for understanding climate change. In this study, the innovative trend analysis (ITA) method was applied to investigate trends in air temperature and precipitation over the Jinsha River Basin (JRB), China, from 1961 to 2016 based on 40 meteorological stations. Climatic factors series were divided into three categories according to percentile, and the hidden trends were evaluated separately. The ITA results show that annual and seasonal temperatures have significantly increased whereas the variation range of annual temperature tended to narrow. Spatial pattern analysis of the temperature indicates that high elevation areas show more increasing trends than flat areas. Furthermore, according to ITA, significant increase trends are observed in annual precipitation and “high” category of spring precipitation. The sub-basins results show a significant decreasing trend in elevation zones of ≤2000 m and an increasing trend where elevation is >2000 m. Moreover, linkage between temperature and precipitation was analyzed and the potential impact of the combined changes was demonstrated. The results of this study provide a reference for future water resources planning in the JRB and will help advance the understanding of climate change in similar areas.

Regional Brain Growth Trajectories in Fetuses with Congenital Heart Disease.

Congenital heart disease (CHD) is associated with abnormal brain development in utero. We applied innovative fetal magnetic resonance imaging (MRI) techniques to determine whether reduced fetal cerebral substrate delivery impacts the brain globally, or in a region-specific pattern. Our novel design included two control groups, one with and the other without a family history of CHD, to explore the contribution of shared genes and/or fetal environment to brain development. From 2014 to 2018, we enrolled 179 pregnant women into 4 groups: "HLHS/TGA" fetuses with hypoplastic left heart syndrome (HLHS) or transposition of the great arteries (TGA), diagnoses with lowest fetal cerebral substrate delivery; "CHD-other," with other CHD diagnoses; "CHD-related," healthy with a CHD family history; and "optimal control," healthy without a family history. Two MRIs were obtained between 18 and 40 weeks gestation. Random effect regression models assessed group differences in brain volumes and relationships to hemodynamic variables. HLHS/TGA (n = 24), CHD-other (50), and CHD-related (34) groups each had generally smaller brain volumes than the optimal controls (71). Compared with CHD-related, the HLHS/TGA group had smaller subplate (-13.3% [standard error = 4.3%], p < 0.01) and intermediate (-13.7% [4.3%], p < 0.01) zones, with a similar trend in ventricular zone (-7.1% [1.9%], p = 0.07). These volumetric reductions were associated with lower cerebral substrate delivery. Fetuses with CHD, especially those with lowest cerebral substrate delivery, show a region-specific pattern of small brain volumes and impaired brain growth before 32 weeks gestation. The brains of fetuses with CHD were more similar to those of CHD-related than optimal controls, suggesting genetic or environmental factors also contribute. ANN NEUROL 2021;89:143-157.

Spatial-temporal Characteristics of Green Development Efficiency and Influencing Factors in Restricted Development Zones: A Case Study of Jilin Province, China

Green development is an important issue of sustainable development in China. Due to the relatively backward economy and the fragile ecological environment, restricted development zones need to embrace green development. Taking 38 counties in Jilin Province as the empirical research objects, and based on cross-sectional data for each county in 2005, 2010, and 2015, we accurately depicted the spatiotemporal evolutionary characteristics of green development efficiency (GDE) in restricted development zones of Jilin Province using the slacks-based measure-data envelope analysis (SBM-DEA) model. Moreover, the factors that influence GDE were further analyzed using the Tobit model. We found that: first, GDE showed a V-shaped trend in restricted development zones of Jilin Province. The differences in GDE in the eastern, central, and western Jilin Province increased gradually. Second, 76% of counties in the restricted development zones had high or higher efficiencies. The resource-based cities were the main areas with low or lower GDE. Third, the economic development level was the core factor affecting GDE. Urbanization level had a significant negative effect on GDE in the restricted development zones. The effect of technological innovation level on GDE fluctuated, and we found that a ‘backward mechanism’ of technological innovation was beginning to form. Industrial structure and environmental governance had no significant effects on GDE.

The Anatomy and Origin of a Synconvergent Grenvillian-Age Metamorphic Core Complex, Chottanagpur Gneiss Complex, Eastern India

Abstract Amphibolite facies supracrustal rocks interleaved with granite mylonites constitute a shallowly dipping carapace overlying granulite facies anatectic basement gneisses in the Giridih-Dumka-Deoghar-Chakai area that spans ~11,000 km2 in the Chottanagpur Gneiss Complex (CGC). Steep N-trending tectonic fabrics in the gneisses include recumbent folds adjacent to the overlying carapace. The basement and carapace are dissected by steep-dipping sinistral shear zones with shallow/moderately plunging stretching lineations. The shear zones trend NNE in the north (north-down kinematics) and ESE in the south (south-down kinematics). Chemical ages in metamorphic monazites in the lithodemic units are overwhelmingly Grenvillian in age (1.0–0.9 Ga), with rafts of older domains in the basement gneisses (1.7–1.45 Ga), granitoids (1.4–1.3 Ga), and the supracrustal rock (1.2–1.1 Ga). P-T pseudosection analysis indicates the supracrustal rocks within the carapace experienced postthrusting midcrustal heating (640–690°C); the Grenvillian-age P-T path is distinct from the existing Early Mesoproterozoic P-T path reconstructed for the basement gneisses. Quartz opening angle thermometry indicates that high temperature (~600°C) persisted during deformation in the southern shear zone. Kinematic vorticity values in carapace-hosted granitoid mylonites and in steep-dipping shear zones suggest transpressional deformation involved a considerable pure shear component. Crystallographic vorticity axis analysis also indicates heterogeneous deformation, with some samples recording a triclinic strain. The basement-carapace composite was extruded along an inclined channel bound by the steep left-lateral transpressional shear zones. Differential viscous extrusion during crustal shortening coupled with the collapse of the thickened crust caused midcrustal flow along flat-lying detachments in the carapace.

Assessment of soil loss by water erosion in small river basins in Russia

Prolonged and intensive agricultural exploitation in the European territory of Russia has resulted in extensive soil erosion, which has led to anthropogenically induced degradation of arable land. The extensive agricultural development of the region stems from the presence of plains suitable for plowing, which feature fertile chernozem (Luvic Chernozems) and grey forest (Luvisols) soils. The majority of the land in the small river basins (70–80%) are plowed. In addition, this macroregion of Russia is the main agricultural territory that provides food for the entire country. The total arable area comprises approximately 600,000 km2. Approximately 95 million people, the majority of the population of Russia, live in this region. This research aims to provide a quantitative assessment of the soil lost by erosion in the arable lands of the macroregion using an USLE empirical mathematical model modified to suit the harsh climatic conditions of Russia. The calculation was performed using a raster model of the data that includes a model of the slope angle, slope length, soil erodibility, rainfall erosivity factor, water content of the snow, annual distribution of precipitation, and types of land use. The location of arable lands of the territory were determined by remote sensing measurements and the TerraNorteRLCv.3 (2014) map compiled by the Space Research Institute of the Russian Academy of Science. For the first time, the intensity of soil erosion over periods of snowmelt and storm runoff, as well as the total annual soil loss, were determined for this territory at a regional scale (1:500,000). The results of these calculations were generalized for small river basins. For this generalization, we used a grid we had previously designed that features over 50,000 river basins.. The average soil erosion in the territory studied amounts to 4.04 t ha−1 year−1, considering the soil-protective coefficients of agricultural vegetation. In the annual soil loss by erosion, storm runoff erosion prevails at 3.78 t ha−1 year−1 and the erosion by snowmelt is considerably lower at only 0.26 t ha−1 year−1.As expected, due to the higher values of the relief (length-slope) factor, soil erosion increases from the lowland plains (3.65 t ha−1 year−1) to the high plains (5.38 t ha−1 year−1), peaking in the mountains (12.88 t ha−1 year−1). The rate of soil erosion of arable lands consistently decreases from the taiga and forest landscape subzone to the steppes. An east–west trending zone featuring the highest soil erosion was distinguished. This zone of high soil erosion coincides with the mixed and broad-leaved forests subzone, which is highly used for plowing. Moreover, a western longitudinal sector of high soil erosion that includes the forest and forest-steppe landscape zones was also determined.

Deformation conditions and kinematics of fault rocks in the Hatagawa Fault Zone and the Shajigami Shear Zone, Northeast Japan: Insights from calcite and quartz microstructures

Calcite grains are plastically deformed at lower temperatures than are quartz grains, which means that investigating the microstructures of both minerals should provide useful information regarding the deformation history of faults. We investigated the conditions of deformation and kinematics of fault rocks within the Hatagawa Fault Zone and the Shajigami Shear Zone, Northeast Japan, using deformation microstructures and crystallographic preferred orientations of quartz and calcite. The Hatagawa Fault Zone trends NNW–SSE, and the associated foliated granite cataclasites show sinistral shear. Limestone mylonite samples showing sinistral shearing display girdles of calcite c-axes close to the YZ plane and Z-maximum, suggesting relatively high and low temperatures of deformation, respectively. The Shajigami Shear Zone trends NE–SW, and quartz microstructures in granodiorite mylonites of the shear zone indicate dislocation creep at temperatures of 400–500 °C. The limestone mylonites have Z-maximum patterns of calcite c-axes. These fault rocks were deformed during the Cretaceous (before the Cenozoic 40° counterclockwise rotation of Northeast Japan) in a kinematic framework characterized by a shortening direction that rotated from N–S to NW–SE. The kinematics and deformation ages of the fault rocks correspond to a change in the direction of motion of the Izanagi Plate at c. 100 Ma.

Genotyping-by-sequencing and ecological niche modeling illuminate phylogeography, admixture, and Pleistocene range dynamics in quaking aspen (Populus tremuloides).

Populus tremuloides is the widest‐ranging tree species in North America and an ecologically important component of mesic forest ecosystems displaced by the Pleistocene glaciations. Using phylogeographic analyses of genome‐wide SNPs (34,796 SNPs, 183 individuals) and ecological niche modeling, we inferred population structure, ploidy levels, admixture, and Pleistocene range dynamics of P. tremuloides, and tested several historical biogeographical hypotheses. We found three genetic lineages located mainly in coastal–Cascades (cluster 1), east‐slope Cascades–Sierra Nevadas–Northern Rockies (cluster 2), and U.S. Rocky Mountains through southern Canadian (cluster 3) regions of the P. tremuloides range, with tree graph relationships of the form ((cluster 1, cluster 2), cluster 3). Populations consisted mainly of diploids (86%) but also small numbers of triploids (12%) and tetraploids (1%), and ploidy did not adversely affect our genetic inferences. The main vector of admixture was from cluster 3 into cluster 2, with the admixture zone trending northwest through the Rocky Mountains along a recognized phenotypic cline (Utah to Idaho). Clusters 1 and 2 provided strong support for the “stable‐edge hypothesis” that unglaciated southwestern populations persisted in situ since the last glaciation. By contrast, despite a lack of clinal genetic variation, cluster 3 exhibited “trailing‐edge” dynamics from niche suitability predictions signifying complete northward postglacial expansion. Results were also consistent with the “inland dispersal hypothesis” predicting postglacial assembly of Pacific Northwestern forest ecosystems, but rejected the hypothesis that Pacific‐coastal populations were colonized during outburst flooding from glacial Lake Missoula. Overall, congruent patterns between our phylogeographic and ecological niche modeling results and fossil pollen data demonstrate complex mixtures of stable‐edge, refugial locations, and postglacial expansion within P. tremuloides. These findings confirm and refine previous genetic studies, while strongly supporting a distinct Pacific‐coastal genetic lineage of quaking aspen.

Trace metal and nutrient dynamics across broad biogeochemical gradients in the Indian and Pacific sectors of the Southern Ocean

The Southern Ocean is the largest high-nutrient low-chlorophyll environment in the global ocean, and represents an important source of intermediate and deep waters to lower latitudes. Constraining Southern Ocean trace metal biogeochemical cycling is therefore important not just for understanding biological productivity and carbon cycling regionally, but also for understanding trace metal distributions throughout the lower latitude oceans. We present dissolved Fe, Ni, Cu, Zn, Cd, Pb and macronutrient concentrations in the Indian and Pacific sectors of the Southern Ocean from the Antarctic Circumnavigation Expedition (austral summer 2016-17), which included the first opportunities to study trace metal cycling at the Mertz Glacier Polynya and the Balleny Islands, as well as two meridional cross-frontal transects. Dissolved Ni, Cu, Zn, Cd and macronutrient concentrations show similar or greater variability latitudinally within surface waters than vertically through the water column, reflecting the combined influence of circulation and biological drawdown in shaping the distributions of nutrient-type elements in the Southern Ocean. Slopes of Cu-Si(OH)4 and Cd-PO4 increase from the Polar Frontal Zone to south of the Southern ACC Boundary (Cu-Si(OH)4) and from the Subantarctic Zone to the Antarctic Zone (Cd-PO4). Latitudinal differences are also observed for Ni-Si(OH)4 and Zn-PO4, with distinct Subantarctic Zone trends relative to those south of the Polar Front. Similarities between our Zn-Si(OH)4 and Cd-PO4 correlations and global compilations reflect the importance of exported Southern Ocean waters in setting these metal-macronutrient couples globally. Distinct Ni-macronutrient correlations are observed in this dataset relative to the global ocean, which supports a distinct cycling of Ni in the Southern Ocean compared to other basins. Concentrations of Pb are among the lowest observed in the global ocean; however, a local maximum is seen along the density level corresponding with Antarctic Intermediate Water. Concentrations within this isopycnal decrease with increasing latitude, which can be explained by decreasing atmospheric Pb input to more recently subducted waters.Substantial biological uptake of metals and macronutrients is observed at the Mertz Glacier Polynya. Here, inferred metal:macronutrient uptake ratios are comparable to those found in the Amundsen Sea Polynya, in Southern Ocean phytoplankton, and to metal-macronutrient correlations in our data set as a whole, highlighting the potential of Southern Ocean polynyas as natural systems for trace metal uptake and export studies. The Balleny Islands are a source of Fe to surface waters and the islands also appear to influence distributions of Zn, Cu and macronutrients, which may reflect the combined impact of Fe supply on biological uptake, mixing, and scavenging in deeper waters. The Kerguelen Plateau is also a source of Fe, as previously identified. Throughout our dataset, the ferricline is found deeper than the nitricline, in agreement with existing data and indicating that Fe is less easily entrained into the surface ocean than NO3. Additionally, Fe:NO3 ratios in most samples throughout the water column are Fe-limiting (<0.01 mmol mol−1). Therefore deep mixing, identified previously as the main Fe source to much of the Southern Ocean, would ultimately act to maintain Fe limitation.

Análise da compartimentação estrutural do sistema aquífero embasamento cristalino no município de Bagé (RS) com base no uso de lineamentos (SRTM e magnéticos) e de dados hidrogeológicos

Esse artigo apresenta o estudo de avaliação da compartimentação e do comportamento hidrogeológico do Sistema Aquífero Embasamento Cristalino, no município de Bagé (RS). Para realização desse estudo, foram utilizados dados hidrogeológicos de 174 poços tubulares e dados de lineamentos obtidos de imagens SRTM e de levantamento aerogeofísico. Para realizar a avaliação estrutural da área, foram traçados lineamentos morfoestruturais nas imagens SRTM, em diferentes escalas (1:1.000.000; 1:500.000 e 1:250.000), bem como foram identificadas estruturas por meio da análise e interpretação dos dados aeromagnéticos. Esses dados foram utilizados visando identificar a existência de compartimentos estruturais. Os dados dos poços tubulares foram analisados e utilizados na caracterização hidrogeológica da área de estudo e dos compartimentos estruturais. Os resultados indicaram a ocorrência de cinco estruturas principais, que possuem extensões entre 8,62 e 30km. Com base nessas estruturas, foram definidas cinco zonas (Z1 a Z5) que possuem características distintas. A Zona 1 apresenta os principais trends para N80-90E e N60-70E, capacidade específica de 0,005 m3/h/m e vazão de 0,46 m3/h. Na Zona 2 os principais trends são para N20-30E, N50-60E e N30-40E, a capacidade específica máxima é de 6,93 m3/h/m, com vazão máxima de 16,5 m3/h. Na Zona 3 os trends são N50-60E, N40-50E e N30-40E, com capacidade específica máxima de 3 m3/h/m e vazão máxima de 20,37 m3/h. Na Zona 4 os principais trends são para N70-80E e N20-30E, com capacidade específica máxima de 2,13 m3/h/m e vazão máxima de 12 m3/h. Por fim, na Zona 5 os trends principais são para N70-80E, N20-30E e N00-10W, com capacidade específica máxima de 1,5 m3/h/m e vazão máxima de 30 m3/h. Esses resultados demonstram que a região do município de Bagé se apresenta compartimentada, com zonas apresentando diferentes produtividades e trends estruturais, sendo que a Zona 2 apresenta estruturas que estão associadas a maior produtividade de poços. Assim, a análise de lineamentos magnéticos e morfoestruturais, demonstra ser um estudo que tem importância na avaliação da compartimentação estrutural e hidrogeológica de áreas com ocorrência de aquíferos fraturados.

Effects of Groundwater Level Changes Associated with Coastline Changes in Coastal Wetlands

Coastline changes caused by anthropogenic and natural influences inevitably alter coastal wetland groundwater levels. In this study, we apply Visual MODFLOW (VMOD) to assess the influence of different zonal coastline types (e.g., accretion, erosion, and stable zones) on groundwater levels of a coastal wetland in the Yellow River Delta (YRD), China. We also discuss the conceptual framework of groundwater level variation in accretion, erosion, and stable zones. Results show that: (i) The groundwater flow field varied with coastline changes in this seaside region, while a similar variation pattern was also found in both the upper southwestern region and the riverside of the Yellow River where groundwater levels are high; (ii) groundwater levels increased with the expansion in land area caused by silting, while groundwater levels exhibited a slightly decreasing trend in the erosion zone; and (iii) coastal wetland groundwater levels exhibited a progressively and significantly decreasing trend in zones protected by a dam. We found that the mechanisms that drive groundwater levels clearly responded to coastline alteration, and such findings could help in our understanding of how coastlines influence groundwater in freshwater wetlands and aid in maintaining the integrity of coastal wetlands.

Climate change and future trends in the Agro-Pastoral Transitional Zone in Northern China: The comprehensive analysis with the historical observation and the model simulation

Climate change and future trends in the Agro-Pastoral Transitional Zone in Northern China: The comprehensive analysis with the historical observation and the model simulation

Delineation of Bitumen Saturated Zones in Agbabu, Southwestern Nigeria, Using an Integrated Geophysical Methods

Delineation of bitumen saturated zones in Agbabu, southwestern Nigeria was carried out using an integrated geophysical methods involving the groundmagnetic and electrical resistivity methods. A total of four magnetic traverses were established in the East-west direction, each covering a total length of 130m. The groundmagnetic results revealed geologic structures favourable to accumulation of bitumen and its occurrence at near-surface. It was also revealed that the bituminous zone trend in the East- West direction of the study area. Two techniques was adopted under electrical resistivity method, the horizontal electrica profiling (HEP) and the vertical electrical sounding (VES). The HEP was used to measure the subsurface electrical variations and lateral extent of bitumen over the study area. Four traverses were established in the North-South direction for HEP and were used to generate electrical profiling curves, which showed low resistivity signatures over the study area. The low resistivity signatures were attributed to the intrusion of saline water to the bituminous zones. Two vertical electrical soundings (VES) were carried out, VES1 and VES2 which were carried out on traverse 1 and traverse 3 had five and six geologic layers respectively. The bitumen saturated zones were found to be within layers three and four and underlained by saline water. The average depth to the bitumen saturated zones was found to be between 3.1m and 23.3m downwards. The near-surface occurrence of natural bitumen and the intrusion of saline water might hinder the feasibility of pure and quality water from the shallow hand-dug wells within the study area.

Change features of time-series climate variables from 1962 to 2016 in Inner Mongolia, China

Detecting change features of climate variables in arid/semi-arid areas is essential for understanding related climate change patterns and the driving and evolution mechanism between climate and arid/semi-arid ecosystems. This paper takes Inner Mongolia of China, a unique arid/semi-arid ecosystem, as the study area. We first detected trend features of climate variables using the linear trend analysis method and then detected their trend-shift features using the breaks for additive seasonal and trend method based on the time-series of monthly precipitation and monthly mean temperature datasets from 1962 to 2016. We analyzed the different change features of precipitation and temperature on a regional scale and in different ecological zones to discover the spatial heterogeneity of change features. The results showed that Inner Mongolia has become warmer-wetter during the past 54 years. The regional annual mean temperature increased 0.4°C per decade with a change rate of 56.2%. The regional annual precipitation increased 0.07 mm per decade with a slightly change rate of about 1.7%, but the trend was not statistically significant. The warmer trend was contributed by the same positive trend in each season, while the wetter trend was contributed by the negative trend of the summer precipitation and the positive trend of the other three seasons. The regional monthly precipitation series had a trend-shift pattern with a structural breakpoint in the year 1999, while the regional monthly mean temperature series showed an increasing trend without a periodical trend-shift. After the year 2000, the warmer-wetter trend of the climate in Inner Mongolia was accelerated. The late 20th century was a key period, because the acceleration of the wetter trend in some local zones (I and II) and the alleviation of the warmer trend in some local zones (VII, VIII and IX) occurred simultaneously. Moreover, the change features had a strong spatial heterogeneity, the southeastern and southwestern of Inner Mongolia went through a warmer-drier trend compared with the other areas. The spatio-temporal heterogeneity of the climate change features is a necessary background for various types of research, such as regional climate change, the evolution of arid/semi-arid ecosystems, and the interaction mechanisms between climate and arid/semi-arid ecosystems based on earth-system models in Inner Mongolia.

Geotechnical data synthesis for GIS-based analysis of fault zone geometry and hazard in an urban environment

AbstractMany fault zones trend through developed urban areas where their geomorphic expression is unclear, making it difficult to study fault zone details and assess seismic hazard. One example is the Holocene-active Rose Canyon fault zone, a strike-slip fault with potential to produce a M6.9 earthquake, which traverses the city of San Diego, California (USA). Several strands trend through densely populated areas, including downtown. Much of the developed environment in San Diego predates aerial imagery, making assessment of the natural landscape difficult. To comply with regulations on development in a seismically active area, geotechnical firms have conducted many private, small-scale fault studies in downtown San Diego since the 1980s. However, each report is site specific with minimal integration between neighboring sites, and there exists no resource where all data can be viewed simultaneously on a regional scale. Here, geotechnical data were mined from 268 individual reports and synthesized into an interactive geodatabase to elucidate fault geometry through downtown San Diego. In the geodatabase, fault segments were assigned a hazard classification, and their strike and dip characterized. Results show an active zone of discontinuous fault segments trending north-south in eastern downtown, including active faults outside the mapped regulatory Earthquake Fault Zone. Analysis of fault geometry shows high variability along strike that may be associated with a stepover into San Diego Bay. This type of geodatabase offers a method for compiling and analyzing a high volume of small-scale fault investigations for a more comprehensive understanding of fault zones located in developed regions.

Microbial diversity and long-term geochemical trends in the euxinic zone of a marine, meromictic lake

Hypoxic and anoxic niches of meromictic lakes are important sites for studying the microbial ecology of conditions resembling ancient Earth. The expansion and increasing global distribution of such environments also means that information about them serves to understand future phenomena. In this study, a long-term chemical dataset (1996–2015) was explored together with seasonal (in 2015) information on the diversity and abundance of bacterial and archaeal communities residing in the chemocline, monimolimnion and surface sediment of the marine meromictic Rogoznica Lake. The results of quantitative PCR assays, and high-throughput sequencing, targeting 16S rRNA genes and transcripts, revealed a clear vertical structure of the microbial community with Gammaproteobacteria (Halochromatium) and cyanobacteria (Synechococcus spp.) dominating the chemocline, Deltaproteobacteria and Bacteroidetes dominating the monimolimnion, and significantly more abundant archaeal populations in the surface sediment, most of which affiliated to Nanoarchaeota. Seasonal changes in the community structure and abundance were not pronounced. Diversity in Rogoznica Lake was found to be high, presumably as a consequence of stable environmental conditions accompanied by high dissolved carbon and nutrient concentrations. Long-term data indicated that Rogoznica Lake exhibited climate changes that could alter its physico-chemical features and, consequently, induce structural and physiological changes within its microbial community.