Central Basin Research Articles

Chronological Study of Coal‐seam Water and its Implication on Gas Production in the South Qinshui Basin

AbstractThe knowledge of the residence time of formation water is fundamental to understanding the subsurface flow and hydrological setting. To better identify the origin and evolution of coal seam water and its impact on gas storage and production, this study collected coalbed methane co‐produced water in the southeast Qinshui Basin and detected chemical and isotopic compositions, especially 36Cl and 129I concentrations. The calculated tracer ages of 129I (5.2–50.6 Ma) and 36Cl (0.13–0.76 Ma) are significantly younger than the age of coal‐bearing formation (Pennsylvanian ‐ Cisuralian), indicating freshwater recharge after coal deposition. The model that utilises 129I/I and 36Cl/Cl ratios to constrain the timing of recharge and the proportion of recharge water reveals that over 60% of pre‐anthropogenic meteoric water entered coal seams since 10 Ma and mixed with residue initial deposition water, corresponding to the basin inversion in Cenozoic. The spatial distribution of major ion concentrations reveals the primary recharge pathway for meteoric water from coal outcrops at the eastern margin to the basin center. This study demonstrates the occurrence of higher gas production rates from wells that accept water recharge in recent times and suggests the possible potential of the non‐stagnant zones for high gas production.

Origin of high heat flow in the back-arc basins of Sumatra: An opportunity for geothermal energy development

Volcanic arcs such as the Barisan Mountains have been identified as attractive areas for the utilization of geothermal energy, as exemplified by Ulubelu in Lampung and Sarulla in North Sumatra. However, environmental factors in the Barisan Mountains remain a primary obstacle to the exploration and exploitation of geothermal energy. The back-arc basins of Sumatra exhibit the highest heat flow worldwide; however, the heat source in this area remains a controversial issue. This study aims to investigate the origin of the high heat flow in the back-arc basins of Sumatra (North, Central, and South Sumatra basins) based on geothermal data from 384 oil wells and the current literature for geological evaluation. The findings of this study indicate that the back-arc basins of Sumatra experienced severe extensional deformation during the Tertiary Period through a large pull-apart and slab rollback mechanism. This deformation resulted in the thinning of the continental crust in this region (27–32 km) and the formation of multiple normal faults. Consequently, the presence of magma resulting from mantle upwelling implies a high heat flow in the back-arc basins of Sumatra. This condition ranks the back-arc basins of Sumatra among the highest heat flow regions of the world, with heat flows >100 mW/m2. These findings indicate that the back-arc basins of Sumatra have significant opportunities to exploit their geothermal energy potential. This study provides novel insights into the potential of geothermal energy, particularly in the back-arc basins of Sumatra.

Hydrogeochemical and isotopic assessment of the origin of NO3− and N–NH3 contents in the aquifer located in a closed lacustrine volcano-sedimentary basin in the metropolitan area of Mexico City

To explain the presence and spatial distribution of NO3− and N–NH3 in the Aquifer of the Metropolitan Area of Mexico City (AMAMC), a hydrogeochemical and isotopic analysis using 13CDIC (as well as the stable isotopes 18O and 2H) in groundwater was conducted. This aquifer is located in an old closed lacustrine volcano-sedimentary basin; some wells hosted in the semi-confined zone contain high N–NH3 concentrations, while others present NO3− contents in the recharge zones (hosted in an oxidizing environment). In this study, a change in the isotopic signature (primarily in 18O and 2H) was observed from the recharge zones to the basin center in some of the wells with high NO3− concentrations, this behavior can be attributed to evaporation during the incorporation of recently infiltrated water. In addition, the results for 13C (along with 2H) in wells with the highest N–NH3 concentrations exhibited an atypically broad range of values. Results indicated the occurrence of hydrogeochemical and/or biochemical processes in the aquifer (in an oxidizing or reducing environment), such as organic degradation, bacterial decomposition (primarily in the ancient Lake Texcoco and which acts as a natural sink for carbon, nitrogen, sulfur, and phosphorus), besides rock weathering and dissolution, which may be responsible for a very marked isotopic modification of the 13C (and, to a lesser extent, 2H). Methanotrophic bacterial activity and methanogenic activity may be related to N–NH3 removal processes by oxidation and residual water incorporation respectively, whereas the increase in the NO3− content in some wells is due to the recent contribution of poor-quality water due to contamination.

Geometry, kinematics, and mechanics of the interaction between strike-slip and normal faults in active rifts: An example from the Quaternary-active Kane Springs Wash fault zone, Nevada, USA

Abstract The interactions among dip-slip and strike-slip faults are critical features in rift segmentation, including strain and slip transfer between faults of different rift segments. Here, we focused on the influence of factors such as fault and fracture geometries, kinematics, and local stress fields on the interaction and linkage of synchronous strike-slip and normal faults. Well-exposed faults along the tectonically active boundary between the central and northern Basin and Range provided for both reliable geometric data and consideration of rift segment development. We documented relative ages and distributions of Quaternary deposits, scarps, and geometries of three ~20–65-km-long Quaternary faults: the N-striking, normal Coyote Spring fault; the ENE-striking, left-lateral Kane Springs Wash fault; and the N-striking, normal Wildcat Wash fault. The normal faults bend to accommodate slip-type differences across linkage zones, with the strike-slip fault and local processes influencing interactions. Influenced by the local stress field of the Kane Springs Wash fault, the Coyote Spring fault bends SE as it approaches and links to the Kane Springs Wash fault. Influenced by the off-fault or process-zone fractures of the Kane Springs Wash fault, the Wildcat Wash fault bends NE and links with the Kane Springs Wash fault. The Kane Springs Wash fault continues beyond the normal fault terminations, suggesting slip transfer between them via the Kane Springs Wash fault. These relations and the ages of offset units suggest that activity on the faults was approximately synchronous despite slip-type differences. Consequently, in slip transfer, the local strike-slip stress environment and off-fault fractures influenced the geometry of the normal fault terminations; the strike-slip fault formed a boundary to dip-slip fault propagation; and this boundary facilitated kinematic and geodetic segmentation, forming a Basin and Range rift segment boundary.

Multi‐channel seismic reflection study of tectonic–sedimentary features and subduction initiation in the middle Kyushu–Palau Ridge and adjacent basins

AbstractThe Kyushu–Palau Ridge and adjacent basins are ideal locations for investigating the formation and evolution of marginal seas and initiation of plate subduction. In this study, the tectonic–sedimentary features and crustal structure of the Kyushu–Palau Ridge and adjacent basins were investigated using newly obtained deep seismic reflection and borehole data. The initial mechanism of subduction in the West Philippine Sea and its tectonic evolution are discussed. Two sets of sedimentary strata with different provenances occur in the eastern Philippine Basin. The thickness of the lower strata is variable, and most of the sediment was sourced from island arc volcanism on the Kyushu–Palau Ridge. These strata thicken towards the Kyushu–Palau Ridge, and volcaniclastic rock aprons are developed near the foot of the Kyushu–Palau Ridge. The upper strata have a relatively uniform thickness and comprise fine‐grained, deep‐water marine sediments. The crustal thickness of the West Philippine and Parece Vela Basins is 6–7 km, which is similar to the global average thickness of oceanic crust. The Moho beneath the West Philippine Basin has a broad and undulating form that mimics the thickness of the oceanic crust beneath the sediments. The depth to the Moho decreases towards the Central Basin Spreading Center. The Moho beneath the Parece Vela Basin is planar, which is in contrast to the undulating nature of the oceanic crust base in this area. The West Philippine Basin may have been located at the northern margin of Australia in the Southern Hemisphere during the Mesozoic. It developed gradually in a continental margin arc as a result of Palaeogene inter‐arc and oceanic extension and contains fragments of continental crust. Seismic profiles and drillhole data in the West Philippine Basin reveal that compression occurred during the Eocene. Subduction along the paleo‐Izu–Bonin–Mariana arc may have been caused by the far‐field effects of the India–Asia collision. Subduction was accompanied by lateral propagation and a compressive stress field until the break‐up of the island arc at ca. 30 Ma.

Productivity and organic carbon loading control uranium isotope behavior in ancient reducing settings: Implications for the paleoredox proxy

Uranium isotopes in ancient sedimentary rocks have emerged as a powerful proxy for the oxygenation history of Earth surface environments. Proper quantitative interpretation of δ238U data hinges, however, on an understanding of isotopic fractionation associated with uranium removal to sediments under different redox conditions. Whereas oxygenated environments are plentiful in the modern ocean, euxinic settings are scarce today, and persistently ferruginous settings are not a feature in the modern ocean, leaving lakes as our best analogs for iron-rich waters. These challenges to studying δ238U behavior under contemporaneous oxic, euxinic (sulfidic), and ferruginous (iron-rich) marine conditions limit our ability to apply the isotope proxy to ancient oceans. Here, we present δ238U data from five coeval cores through the Lower Mississippian Sunbury Shale of the semi-restricted Appalachian Basin (North America), which were deposited across a strong redox gradient from intermittently oxic conditions proximal to the Catskill Delta, to ferruginous conditions in the central basin axis and euxinic conditions along the basin-bounding Cumberland Sill. Overall, we find that both euxinic and ferruginous environments are capable of imparting high degrees of uranium isotope fractionation and that δ238U values covary more strongly with total organic carbon (TOC) and trace metal abundances than they do with the presence of euxinic versus ferruginous conditions. We suggest uranium sorption or incorporation into sinking organic matter in the water column as a mechanism for generating positive covariation between δ238U and TOC, particularly at lower TOC concentrations. We also compare our δ238U data to broadly coeval carbonates from Nevada, which can be used to estimate Early Mississippian seawater δ238U values. We find that Sunbury Shale cores deposited under stably anoxic conditions (both euxinic and ferruginous) and under consistently brackish salinities away from freshwater sources record an increasing δ238U trend through time that loosely mirrors the record for carbonates (and thus estimates for seawater) with an offset of ∼0.4‰ to 1.1‰, depending on the inferred offset between carbonate and seawater. In contrast, cores deposited close to the Catskill Delta and in a shallow oceanic-restricted basin transition across the Cumberland Sill record a decreasing δ238U trend through time, opposite the inferred seawater trend and suggestive of entirely local controls on δ238U values. Ultimately, these data suggest that highly productive environments with high rates of organic carbon loading can exert a strong control on the global δ238U mass balance regardless of whether euxinic or ferruginous conditions are present. These results necessitate a partial reassessment of the processes controlling δ238U variability in seawater and sedimentary rocks through Earth history.

Geochemical Characteristics of Deep-Sea Sediments in Different Pacific Ocean Regions: Insights from Fractal Modeling

Exploration of mineral resources in the deep sea has become an international trend. However, deep-sea mineral exploration faces challenges such as complex offshore drilling and the weak and mixed signals of ore deposits. Therefore, studying methods for identifying weak and mixed anomalies and extracting composite information in the deep sea is crucial for innovative prediction and evaluation of deep-sea mineral resources. In this study, the Central Pacific Ocean, Northwestern Pacific Ocean, and Eastern Pacific Ocean were selected as research areas. Drawing upon the fractal self-similarity exhibited by rare earth minerals in the deep-sea sediments within the Pacific Ocean, we conducted an analysis and comparison of the fractal geochemical characteristics in various regions of the Pacific Ocean’s deep-sea sediments. Thereafter, we studied the spatial distribution of rare earth elements (REEs) in deep-sea sediments in these regions to explore the mechanisms responsible for rare earth enrichment in the Pacific Ocean. The results revealed that the geochemical fractal characteristics of deep-sea sediments in the Northwestern Pacific Ocean Basin and the Central Pacific Ocean Basin were similar, whereas there were slight differences in the fractal characteristics observed in the Eastern Pacific Ocean Basin. By calculating the singularity index of CaO/P2O5, it was found that the singularity index in the Central and Northwestern Pacific Ocean basins was lower than that in the Eastern Pacific Ocean Basin, suggesting that the phosphorus content in the Eastern Pacific Ocean Basin was lower than that in the Central and Northwestern Pacific Ocean basins. In the Eastern Pacific Ocean, we found that phosphorus content in deep-sea sediments was the primary controlling factor for REE enrichment. Conversely, in the Central and Northwestern Pacific Ocean, both the phosphorus and calcium content in deep-sea sediments played significant roles in REE enrichment.

Oasis of the deep: Cold-water corals of the South China Sea

Cold-water coral (CWC) communities are biodiversity hotspots on the world's deep seafloor. Although deep-sea corals in the South China Sea (SCS) have been reported before, they are only sporadic. A comprehensive and systematic understanding of the CWC in the SCS would forge the basis for future protection. Here we conducted the first systematic survey on the CWCs in the following six broad-scale sub-regions, from the northwest and northeast slopes to the seamounts in the western and central basins of the SCS, through twenty-four dives of the human-occupied vehicle ShenhaiYongshi. Statistical analysis provided detailed information on the distribution, abundance, size, diversity, and density of CWCs and the in situ environmental conditions supporting coral habitats. We found that the SCS hosted highly diversified coral communities, including twelve genera of gorgonians, six genera of black corals, and one genus of stony corals. The differences in the spatial distribution patterns of coral communities suggested that several environmental variables (depth, temperature, salinity, substrate, and geomorphology) might influence the development of CWCs in the SCS. The intermediate water layer of the SCS appeared to provide suitable habitat for deep-sea coral communities and potentially promoted connectivity. Furthermore, differences between sub-regions within the SCS may be an important factor responsible for the biogeographic patterns of CWCs. These sub-regions of CWCs were observed to range from 0.004 to 0.622 corals m−2, with an average of 0.139 corals m−2. The mean density of CWCs in the SCS was relatively high compared to well-studied CWC hotspots. Overall, the results revealed the significance of the SCS as an important CWC hotspot in the world. These findings provide a fundamental basis for the protection of deep-sea coral assemblages in the SCS.

Cyclicity of the Lower Buntsandstein in the eastern part of the Central European Basin: implications for Early Triassic palaeogeography and for geochronological calibration

Lower Buntsandstein small–scale cycles recognized in the Central European Basin (CEB) are readily used for astrochronological calibration of the Early Triassic time scales, although they are not well studied sedimentologically. Three borehole sections from the eastern part of the CEB, forming a south-north transect perpendicular to the basin axis, were studied in terms to better understand the depositional history of the Lower Buntsandstein developed as the Baltic Formation in the studied Polish part of the basin. Eleven sedimentary facies were recognized, based on lithological and sedimentological investigations of 655.7 m of drill cores from the Otyń IG 1, Gorzów Wielkopolski IG 1 and Kamień Pomorski IG 1 boreholes. The facies can be grouped according to a lithological criterion into facies of predominantly siliciclastic lithology (including 9 facies types) and facies of predominantly carbonate lithology (including 2 facies types). Facies analysis allowed to distinguish 8 facies associations of: 1) alluvial fan, 2) playa, 3) sandy-muddy coastal plain, 4) embayment and distal delta, 5) lagoon, 6) sand bars or shoals, 7) ooidal shoals or bars, and 8) offshore. Deepening-upward (DC) and shallowing-upward (SC) sedimentary cycles were recognized in parts of the Baltic Formation, with DCs dominating in the southernmost located Otyń IG 1, and SCs dominating in Gorzów Wielkopolski IG 1, located in the axial part of the basin. Symmetrical cycles are very rare. The statistical significance of the sedimentary cycles is relatively low according to Markov-chain analysis conducted with the phpSedistat software of Stanova et al. (2009). Analysis of small–scale cycles performed on well logs of investigated boreholes and additional boreholes in the vicinity of Otyń IG 1, implementing the earlier study of Becker (2005), showed that the correlation of well-log cycles (GR cycles) and sedimentary cycles is not obvious. GR cycles can be roughly correlated with lithological carbonate–siliciclastic cycles (c-s cycles), reflecting alternations of facies groups of predominantly carbonate and siliciclastic lithology. Calibration of GR cycles to earlier magnetostratigraphic results of Nawrocki (1997) and Becker and Nawrocki (2014) showed that neither the boundaries of GR cycles serve as reference horizons, nor the cycles document equal time periods. All existing depositional models of the Lower Buntsandstein were discussed, stressing the possible simultaneous interaction of allochthonous and autochthonous processes. Moreover, the tectonic overprint of the Central European Basin system during the Early Triassic should be taken into account. The presented results suggest that the Lower Buntsandstein cyclicity of the CEB cannot serve as a basis for astrochronological analysis.

Study on the Differential Distribution Patterns of Fine-Grained Sedimentary Rocks in the Lower Third Member of the Shahejie Formation in Zhanhua Sag, Bohai Bay Basin

Due to the diverse types of sedimentary source supply systems, the research on the distribution patterns of fine-grained sedimentary rocks in rifted lake basins is relatively underdeveloped. The authors of this article selected the lower third member of the Shahejie Formation (Es3L) in Zhanhua Sag as a research object. Using rock core, thin section, and other data, we analyzed rock types and genesis mechanisms, identified the spatiotemporal distribution patterns of facies within the sag, and established a fine-grained depositional model for the rifted lake basin. Five lithofacies were identified, revealing the differential distribution patterns of fine-grained sedimentary rocks in the region. The northern steep slope zone and the deep depression zone are characterized by the deposition of gravity flow-formed terrestrial layered-pebbly mudstone and gravity flow-formed mixed-source pebbly mudstone, respectively. In the central lake basin zone, mixed-source laminated mudstone with vertical rhythmic interlayers has developed. In the southern gentle slope zone, biologically cemented endogenic irregularly bedded algal limestone and chemically precipitated endogenic laminated limestone have developed. The characteristics of strong northern and weak southern terrestrial inputs in the study area control the differential distribution of lithofacies, and based on this, a fine-grained rock depositional model for the rifted lake basin was established.

Spatial and temporal dynamics of near-bottom dissolved oxygen in the central basin of Lake Erie

Abstract Eutrophication continues in Lake Erie and low oxygen concentration remains a concern in the central basin of the lake. Summertime dissolved oxygen concentrations can be hypoxic (low dissolved oxygen) and anoxic (dissolved oxygen <1 mg l-1) in the hypolimnion. We examined the spatial and temporal patterns of hypoxia in the central basin along a ∼ 26 km west-east station transect in the western portion of the central basin (depth gradient from 11.4 m in the west to 20 m in the east). Water column properties were monitored using moored instruments (dissolved oxygen, temperature, turbidity, Chlorophyll a fluorescence) and instrument profiling during cruises in 2008 and 2009. Hypoxia was examined using a biologically relevant value of 40% dissolved oxygen saturation (i.e. ∼4 mg l-1) and 25% dissolved oxygen saturation (i.e. ∼2.5 mg l-1) as used by government agencies. Our goals were to determine the onset and location of hypoxia, as well as the frequency of hypoxic events. We observed differences in the spatial and temporal patterns between the two years, related potentially to different water levels, stronger winds, and a smaller hypolimnion and lower thermocline depth in 2009. Near-bottom hypoxia occurred in the east at the end of June and extended westward by the end of July 2008 using 40% saturation; in early July to mid-August using 25% saturation. The onset of hypoxia (40% sat) occurred earlier in the west in 2009 but was similar to 2008 using 25% saturation. Hypoxia was not static, rather there were a total of ∼100 events of both levels of hypoxia, which were of different duration, noted across the transect in both years. Both the frequency and duration of hypoxic events (> 1 min) were higher and longer in 2008, perhaps related to water circulation and the resuspension of bottom sediment by synoptic-scale storms, which coincided with low oxygen events. Understanding the spatial and temporal patterns of hypoxia provides insight into their effects on habitat quality as well as biogeochemical processes in benthic and hypolimnetic environments in Lake Erie.

Fishes of the upper rio Paraná basin: diversity, biogeography and conservation

Abstract The upper rio Paraná basin drains the most developed and environmentally degraded region in South America: the Brazilian southeast. While it is one of the most well-known Neotropical fish assemblages, it is also one of the most threatened by anthropic activity. Urbanization, deforestation, dam construction, invasive species, and water pollution not only reduce the living area of species but also alter our perception of the basin and its biotic elements. Such changes are so profound and pervasive that raise uncertainties about the native or non-native status of several species. This paper aims to offer a detailed picture of the native diversity and historical biogeography of the fishes in the upper rio Paraná basin, which we hope will offer a solid foundation for future conservation policies. We update the list of native species, analyze geographical distributions, and identify biogeographical patterns, emphasizing areas requiring recognition as distinct biotas for conservation efforts. Over the past 15 years, more than 100 additional species have been described or recorded, expanding the total to 341 native species belonging to six orders and 30 families, making it the richest river basin in Brazil outside the Amazonian region. Unlike most neotropical basins where Characidae dominates, loricariids make up nearly one-fourth of the total fish diversity in the region. Species and clades concentrate in the central basin, while endemics are confined to peripheral areas due to the complex biogeographical history shared with neighboring basins. Eighteen distinct biogeographical regions are identified, discussing their composition, histories, and conservation implications. The upper rio Paraná basin has 10% of its fish fauna ranked as endangered and present 128 non-native species, including three hybrids. This places it as the major drainage with the largest number of endangered taxa in the neotropics and at the same time the one with the most numerous non-native elements. Existing protected areas are deemed ineffective in preserving diverse assemblages and fail to safeguard the majority of threatened and narrowly-endemic species.

Lake-wide measurements of primary productivity in Lake Erie

Abstract Few lake-wide, seasonal primary production measurements have been made in Lake Erie. None more recent than 1997 have been reported in the literature. In 2019 we used 13C uptake to measure production at 11 stations across the lake during three surveys in May, July, and September and at four of these stations during two additional surveys in April and August. Samples were collected at two depths (2 m and 6 m) and incubated on deck using eight levels of irradiance. We fit the resultant photosynthesis-irradiance curves with models that included the initial slope at low light levels, the maximum photosynthesis rate at light saturation, and when warranted, the negative slope at high irradiance. During May, there was little variation in chlorophyll-normalized volumetric productivity with sample depth, and productivity generally was higher nearshore and in the western basin than it was offshore. The distinction between nearshore and offshore stations was less pronounced in July, but nearshore productivity was higher than offshore in September. Using the photosynthesis data from all five surveys, chlorophyll concentration profiles, and estimated clear-sky solar insolation, we calculated time series of vertically integrated daily production at a western basin station, two central basin stations, and an eastern basin station. Central basin production was highest during August, estimated to be 748 mg C m-2 d-1 and 779 mg C m-2 d-1 at our two stations. Production peaked in July in the western basin (510 mg C m-2 d-1) and September in the eastern basin (421 mg C m-2 d-1). Whole-lake seasonal areal phytoplankton photosynthesis was estimated as 1.661E6 tonnes, about half of estimates made in the 1990s using 14C methods. These results inform our understanding of spatial-temporal trends in Lake Erie productivity and highlight the need for continued measurements of Lake Erie primary production.

Three days at school with FAST

“Three days at school with FAST” is the name of the environmental education project included within the FAST (Fight Alien Species Transborder), Project Interreg Italy-Malta. The FAST Project aims to record the entry and spread of non-native animal and plant species; and even more so those invasive species capable of reducing biodiversity in the islands of Sicily and Malta, located in the center of the Mediterranean basin. Furthermore, an important part of the project concerns dissemination, raising awareness among the community about alien species, the problems associated with them and the protection of biodiversity. Environmental education in schools (today considered an important form of dissemination of good practices) is the focus of the three days at school with FAST. An attempt was made to give the youngest elementary and middle school students tangible experiences, to teach them useful practices for the protection of nature by explaining, for the purposes of greater knowledge and awareness, environmental issues and problems linked to the most well-known and widespread alien species in Sicily, Thanks to the game and the experiences proposed in the three scheduled meetings, the aim is to enhance and at the same time learn to protect local environmental resources.

Tradeoffs Between Temporal and Spatial Pattern Calibration and Their Impacts on Robustness and Transferability of Hydrologic Model Parameters to Ungauged Basins

AbstractOptimization of spatially consistent parameter fields is believed to increase the robustness of parameter estimation and its transferability to ungauged basins. The current paper extends previous multi‐objective and transferability studies by exploring the value of both multi‐basin and spatial pattern calibration of distributed hydrologic models as compared to single‐basin and single‐objective model calibrations, with respect to tradeoffs, performance and transferability. The mesoscale Hydrological Model (mHM) is used across six large central European basins. Model simulations are evaluated against streamflow observations at the basin outlets and remotely sensed evapotranspiration patterns. Several model validation experiments are performed through combinations of single‐ (temporal evaluation through discharge) and multi‐objective (temporal and spatial evaluation through discharge and spatial evapotranspiration patterns) calibrations with holdout experiments saving alternating basins for model evaluation. The study shows that there are very minimal tradeoffs between spatial and temporal performance objectives and that a joint calibration of multiple basins using multiple objective functions provides the most robust estimations of parameter fields that perform better when transferred to ungauged basins. The study indicates that particularly the multi‐basin calibration approach is key for robust parametrizations, and that the addition of an objective function tailored for matching spatial patterns of ET fields alters the spatial parameter fields while significantly improving the spatial pattern performance without any tradeoffs with discharge performance. In light of model equifinality, the minimal tradeoff between spatial and temporal performance shows that adding spatial pattern evaluation to the traditional temporal evaluation of hydrological models can assist in identifying optimal parameter sets.

WRF prediction of an atmospheric river‐related precipitation event: Sensitivity to cumulus parameterization schemes

AbstractThe present study aimed to evaluate performance sensitivity to the Cumulus Parameterization Scheme (CPS) used for the Weather Research and Forecasting (WRF) model to predict the atmospheric river‐related precipitation (ARP) event with 206 and 57 mm, highest and area‐averaged precipitation (AAP) per 24‐h, respectively, that occurred over the central mountainous basins of Iran on 31 March 2019. For this purpose, experiments were designed using the 12 (almost all) CPSs available in WRF v4. To verify the predicted precipitation (from the inner 4‐km domain), both point‐scale and grid‐scale comparisons were performed against gauge‐ and satellite‐based observational data at three accumulation time‐scales (12‐, 18‐, and 24‐h) and in three distinct sub‐regions. All scores obtained from the different statistical metrics used, are in complete agreement with a strongly dependent performance of WRF on the CPS used. In addition, the use of Kain‐Fritsch, KF‐CuP, and Grell‐3 CPSs could provide a realistic picture of impending heavy precipitation for WRF. Contrary, the New SAS, Tiedtke, and Zhang‐McFarlane CPSs did not perform satisfactorily in predicting the ARP event. As a result, CPSs with the “momentum transport” option in their modification mechanism are unlikely to adequately simulate the conversion of incoming low‐level moisture from atmospheric river to precipitation. However, precipitation predictions are more accurate at the 24‐h accumulation time‐scale than at the 12‐ and 18‐h. Also, a dry bias in the predictions is expected as the terrain elevation and accumulation time‐scale decrease and the distance from the core of the precipitation field increases.

Allozyme and cytogenetic analysis in two species of Hypostomus (Siluriformes: Loricariidae) from the Paraguai River basin, Brazil: occurrence of B microchromosome and intrapopulation heterochromatic polymorphism in H. boulengeri

Abstract Hypostomus is distributed by Central and South America basins, with diverse species with taxonomic conflicts. This way, the integration of auxiliary techniques contributes to understanding the systematics and phylogeny of the group. Thus, this study aimed to investigate the Hypostomus cochliodon and H. boulengeri from the Onça stream (Paraguai River basin) by allozyme and cytogenetic techniques. Hypostomus boulengeri showed a diploid number of 68 chromosomes (14m+14sm+18st+22a), multiple NOR revealed by Ag-NOR and 18S rDNA FISH, a polymorphism of heterochromatin in acrocentrics and the presence of B microchromosome. Hypostomus cochliodon showed a diploid number of 64 chromosomes (16m+26sm+14st+8a); despite the single NOR, some individuals showed NOR in both telomeres detected by Ag-NOR and 18S rDNA FISH. Isozyme identified two diagnostic loci (Idh-A and Gdh-A) between the two species and multiple loci with unique alleles in H. boulengeri. The genetic variability indicated by the mean heterozygosity (He) was 0.2461 and 0.0309 in H. boulengeri and H. cochliodon,respectively.Thus, this study reports the first cytogenetic data for H. boulengeri and the first isozymatic data for H. boulengeri and H. cochliodon. The two species presented evident cytogenetic and isoenzymatic differences with the obtaining of exclusive genetic markers providing support for future evolutionary studies in the group.

The study of the criterion of the marginal and dynamic equilibrium of the riverbed

The article analyzes the results of theoretical and experimental studies on the stability criterion of Rusle from non-cohesive soils, and notes their advantages and disadvantages. A significant influence of the average slope and transport sediment flow on head losses was revealed. An assessment was made of the shape of the channel of the limiting and dynamic equilibrium of the channel laid in easily eroded soils - justified for considering the parameters of molasses. A number of empirical substitutabilities are given A number of empirical substitutabilities are given w0=f(d) and i=f(H⁄d), constructed based on hydrometrological data of Central Asian water basins, which can be used for practical calculation of watercourses. An improved method has been proposed that allows the design of river structures taking into account the criterion of equilibrium of fine sand sediment grains.

Modelling effects of immediate rainfall on sap flux of Cypress trees in the Southwest Hilly area of China

Background The hilly region of the central Sichuan basin is one of the most severely affected areas in China in terms of soil and water loss. For this reason, a large area of mixed alder and cypress forest has been established for protection. However, the uneven distribution of rainfall significantly impacts the stability of water usage in the plantations. Therefore, accurately understanding the response of trees to real-time rainfall is essential for effective forests management that optimizes hydrology and water resources. Aims To examine how the sap flux of the cypress forest responds to environmental factors and develop response models for two different conditions.

An overview of the evolution of the internal hellenides (Albania, Republic of North Macedonia, Greek Central Macedonia): obductions, collisions and North Aegean extension

The geological analysis of the Albanian-Macedonian transect constraints a framework of the Internal Hellenides in which 3 or 4 Jurassic oceanic basins opened at 174–160 Ma; they bordered the Western European Continent. During the Late Jurassic, the oceanic crusts subducted eastward, the Mirdita basin below the Pelagonian continent, the Almopias basin below the Malarupa-Veles continent and the Thessaloniki ophiolitic basin below the Continental Margin of the basin. A Paikon Volcanic tholeiitic Island Arc formed above the Almopias subduction and subsequently subducted below the rhyolitic volcanic centre of the Arc; the Guevgueli ophiolitic back-arc basin opened above the subduction of the Paikon Volcanic Arc (164–160 Ma). The top-to-the-W Late Jurassic obduction of the oceanic crusts (D1 event) is followed by a gravitational exhumation (D2 event). A new Mid-Late Cretaceous Almopias marine basin formed; the Late Cretaceous-Palaeocene continental subduction (=collisions, D3-4 events) re-activated the Jurassic subductions and a dacitic Paikon Volcanic Arc formed in the Palaeocene-Early Eocene (56–45 Ma). The Vardar Trough opened at 45 Ma in the back of the dacitic Paikon Volcanic Arc, above the subduction of Vardar and Apulia units; it was submitted in the Late Priabonian to a tectonic event (D5 event, 36–34 Ma) and to the Early Miocene compression (D6 event). The N. Aegean WNW-ESE extension began at ∼21–20 Ma; change from the WNW to the NE-SW/N-S extensional directions occurred between the Tortonian (∼12 Ma) and the Pliocene (∼6 Ma); it was probably driven by hundreds kms of NE-SW/N-S stretching of the Central and Southern Aegean basins.