Vertical Trends Research Articles

Significance of Urea in Sustaining Nitrite Production by Ammonia Oxidizers in the Oligotrophic Ocean

AbstractNitrification, the stepwise oxidation of ammonia to nitrate via nitrite, is a key process in the marine nitrogen cycle. Reported nitrite oxidation rates frequently exceed ammonia oxidation rates below the euphotic zone, raising the fundamental question of whether the two steps are balanced and if alternative sources contribute to nitrite production in the dark ocean. Here we present vertically resolved profiles of ammonia, urea, and nitrite oxidation rates and their kinetic traits in the oligotrophic Subtropical North Pacific. Our results show active urea‐derived nitrogen oxidation (urea‐N oxidation) in the presence of experimental ammonium amendment, suggesting direct urea utilization. The depth‐integrated rates of urea‐N oxidation and ammonia oxidation are comparable, demonstrating that urea‐N oxidation is a significant source of nitrite. The additional nitrite from urea‐N oxidation helps to balance the two steps of nitrification in our study region. Nitrifiers exhibit high affinity for their substrates, and the apparent half‐saturation constants for ammonia and nitrite oxidation decrease with depth. The apparent half‐saturation constant for urea‐N oxidation is higher than that for ammonia oxidation and shows no clear vertical trend. Such kinetic traits may account for the relatively higher urea concentration than ammonium concentration in the ocean's interior. Moreover, a compilation of our results and reported data shows a trend of increased urea‐N oxidation relative to ammonia oxidation from the eutrophic coastal zone to the oligotrophic open ocean. This trend reveals a substrate‐dependent biogeographic distribution of urea‐N oxidation across marine environments and provides new information on the balance and flux of the marine nitrification process.

Pollution trends in a protected fluvial landscape located in a highly industrialized Ostrava urban agglomeration; Rezavka Nature Reserve, Czech Republic

Abandoned meanders and former river channels represent important depositional units of fluvial river systems, making them suitable sedimentary archives for assessing pollution trends. The objective of this study is to provide insight into temporal trends and spatial variability in pollution levels in the selected fluvial elements (an abandoned meander, a former river channel, and a semi-open meander) within the Rezavka Nature Reserve (part of the Poodří protected landscape area) along the Odra River and Mlýnka stream, located in the heavily polluted Ostrava urban agglomeration (Czech Republic). Initial stages of the abandoned meander evolution were characterised by high sediment accumulation rates and decelerated over time, while more regular sediment supply continued in sites close to the semi-open meander of the Mlýnka stream. Pollutants were effectively captured by abandoned meanders with fine-grained infill, while the coarser-grained infill of the former channel was less effective pollutant scavenger. A time frame for deposition was assigned using vertical trends in 137Cs mass activity and selected organic pollutants. The sedimentary record, covering the last ~ 70 years, reveals a distinct vertical pollution trend that reflects industrial development. Pollution levels have increased since the 1950s and will remain high at the end of the 20th century. The depth pattern of heavy metals, as well as their enrichment factors, shows an upward increase. Levels of persistent organic pollutants are typically low or under the limit of detection in the deepest strata, gradually or sharply rising upward.

Tree stem-atmosphere greenhouse gas fluxes in a boreal riparian forest

Tree stems exchange greenhouse gases with the atmosphere but the magnitude, variability and drivers of these fluxes remain poorly understood. Here, we report stem fluxes of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) in a boreal riparian forest, and investigate their spatiotemporal variability and ecosystem level importance. For two years, we measured CO2 and CH4 fluxes on a monthly basis in 14 spruces (Picea abies) and 14 birches (Betula pendula) growing near a headwater stream affected by historic ditching. We also measured N2O fluxes on three occasions. All tree stems were net emitters of CO2 and CH4, while N2O fluxes were around zero. CO2 fluxes correlated strongly with air temperature and peaked in summer. CH4 fluxes correlated modestly with air temperature and solar radiation and peaked in late winter and summer. Trees with larger stem diameter emitted more CO2 and less CH4 and trees closer to the stream emitted more CO2 and CH4. The CO2 and CH4 fluxes did not differ between spruce and birch, but correlations of CO2 fluxes with stem diameter and distance to stream differed between the tree species. The absence of vertical trends in CO2 and CH4 fluxes along the stems and their low correlation with groundwater levels and soil CO2 and CH4 partial pressures suggest tree internal production as the primary source of stem emissions. At the ecosystem level, the stem CO2, CH4 and N2O emissions represented 52 ± 16 % of the forest floor CO2 emissions and 3 ± 1 % and 11 ± 40 % of the forest floor CH4 and N2O uptake, respectively, during the snow-free period (median ± SE). The six month snow-cover period contributed 11 ± 45 % and 40 ± 29 % to annual stem CO2 and CH4 emissions, respectively. Overall, the stem gas fluxes were more typical for upland rather than wetland ecosystems likely due to historic ditching and subsequent groundwater level decrease.

Decoding drivers of carbon flux attenuation in the oceanic biological pump

The biological pump supplies carbon to the oceans’ interior, driving long-term carbon sequestration and providing energy for deep-sea ecosystems1,2. Its efficiency is set by transformations of newly formed particles in the euphotic zone, followed by vertical flux attenuation via mesopelagic processes3. Depth attenuation of the particulate organic carbon (POC) flux is modulated by multiple processes involving zooplankton and/or microbes4,5. Nevertheless, it continues to be mainly parameterized using an empirically derived relationship, the ‘Martin curve’6. The derived power-law exponent is the standard metric used to compare flux attenuation patterns across oceanic provinces7,8. Here we present in situ experimental findings from C-RESPIRE9, a dual particle interceptor and incubator deployed at multiple mesopelagic depths, measuring microbially mediated POC flux attenuation. We find that across six contrasting oceanic regimes, representing a 30-fold range in POC flux, degradation by particle-attached microbes comprised 7–29 per cent of flux attenuation, implying a more influential role for zooplankton in flux attenuation. Microbial remineralization, normalized to POC flux, ranged by 20-fold across sites and depths, with the lowest rates at high POC fluxes. Vertical trends, of up to threefold changes, were linked to strong temperature gradients at low-latitude sites. In contrast, temperature played a lesser role at mid- and high-latitude sites, where vertical trends may be set jointly by particle biochemistry, fragmentation and microbial ecophysiology. This deconstruction of the Martin curve reveals the underpinning mechanisms that drive microbially mediated POC flux attenuation across oceanic provinces.

Riverbed depth-specific microplastics distribution and potential use as process marker

Riverbed sediments have been identified as temporary and long-term accumulation sites for microplastic particles (MPs), but the relocation and retention mechanisms in riverbeds still need to be better understood. In this study, we investigated the depth-specific occurrence and distribution (abundance, type, and size) of MPs in river sediments down to a depth of 100 cm, which had not been previously investigated in riverbeds. In four sediment freeze cores taken for the Main River (Germany), MPs (≥ 100 µm) were detected using two complementary analytical approaches (spectroscopy and thermoanalytical) over the entire depth with an average of 21.7 ± 21.4 MP/kg or 31.5 ± 28.0 mg/kg. Three vertical trends for MP abundance could be derived, fairly constant in top layers (0–‍30 cm), a decrease in middle layers (30–60 cm), and a strong increase in deep layers (60–100 cm). The dominant polymer types were polyethylene (PE), polypropylene (PP), and polystyrene (PS). Polyethylene terephthalate (PET) and PP were also found in deep layers, albeit with the youngest age of earliest possible occurrence (EPO age of 1973 and 1954). The fraction of smaller-sized MPs (100–500 µm) increased with depth in shallow layers, but the largest MPs (> 1 mm) were detected in deep layers. Based on these findings, we elucidate the relationship between the depth-specific MP distribution and the prevailing processes of MP retention and sediment dynamics in the riverbed. We propose some implications and offer an initial conceptual approach, suggesting the use of microplastics as a potential environmental process tracer for driving riverbed sediment dynamics.

Exploring groundwater depletion and land subsidence dynamics in Taiwan’s Choushui river alluvial fan: insights from integrated GNSS and hydrogeological data analysis

The Choushui River Alluvial Fan (CRAF) is a major agricultural area in Taiwan with heavy groundwater usage. The extraction of groundwater here has caused land subsidence, which is now a significant global environmental issue. This study analyzes land subsidence in the CRAF by integrating hydrogeological data from 233 groundwater monitoring stations across four aquifers (CRAF Groundwater_NET) and data from 50 continuous GNSS stations (CRAF GNSS_NET). We developed an automated processing flow for GNSS static surveying within CRAF GNSS_NET, and further employed a time-series fitting method to examine the long-term trends and annual changes for both GNSS and groundwater level data. Our analysis of the time-series data from the past decade identifies areas of significant groundwater level depletion and subsidence hotspots. We explore the relationship between groundwater level variations and surface displacements within CRAF, utilizing GNSS data to analyze horizontal and vertical displacement trends, as well as annual changes. We integrate these findings with hydrogeological data to understand regional subsidence patterns. Our results indicate that CRAF is characterized by distinct hydrogeological features. The study finds that the amplitudes of annual changes in both groundwater level and vertical displacement generally increase from northeast to southwest in the analyzed region. One particular area shows significant groundwater level decline, with the most severe rate recorded at 0.54 m/year. Similarly, GNSS analysis indicates pronounced subsidence trends in the same area, with rates ranging from 4.2 to 5.2 cm/year. These findings highlight the critical need for the development of effective groundwater management strategies to ensure sustainable use of groundwater resources and to implement mitigation measures against land subsidence in similar multiple-aquifer settings.

Mississippian (Lower Carboniferous) Facies Heterogeneity and Distribution within the Mixed Carbonate-Siliciclastic Reservoirs of the Midcontinent STACK Play, Oklahoma, USA

Summary The objective of this study is to evaluate facies heterogeneity, including both lateral and vertical distributions within the mixed carbonate and siliciclastic reservoirs of the Mississippian System (Lower Carboniferous). This research and statistical approach will aid in future investigations related to determining optimal landing zones, enhancing completion designs, and providing geologic insight into fracture driven well interference studies to increase production efficiency. This study integrates well log, petrographic, sedimentologic, and conventional core analyses along a set of transects across the Anadarko Basin and includes the development of core-based facies logs. Statistical analysis indicates that the Mississippian System in the STACK play of the Anadarko Basin is fundamentally a highly layered rhythmic succession in which a variety of carbonate rock types, siliciclastic rock types, and chert tend to form couplets with siltstone. Thickness-frequency distributions and Markov chain analysis indicate that sediment thickness and lithologic transitions were stochastically regulated and that lithologic cyclicity is not apparent. Overall lithologic trends indicate a transition from carbonate to sandstone in the midramp and from carbonate to mudstone and siltstone in the outer ramp. Stratal geometry defines a series of south-prograding clinoforms, and detailed analysis of vertical trends in the distribution of mudstone, siltstone, sandstone, chert, and carbonate facilitates identification of shoaling-upward parasequences that can be correlated regionally.

Critical behaviors of van der Waals itinerant ferromagnet Fe3.8GaTe2

The critical behavior of the van der Waals ferromagnet Fe3.8GaTe2 was systematically studied through measurements of isothermal magnetization, with the magnetic field applied along the c-axis. Fe3.8GaTe2 undergoes a non-continuous paramagnetic to ferromagnetic phase transition at the Curie temperature T c ∼ 355 K. A comprehensive analysis of isotherms around T c utilizing the modified Arrott diagram, the Kouvel–Fisher method, the Widom scaling law, and the critical isotherm analysis yielded the critical exponent of β= 0.411, γ = 1.246, and δ = 3.99. These critical exponents are found to be self-consistent and align well with the scaling equation at high magnetic fields, underscoring the reliability and intrinsic nature of these parameters. However, the low-field data deviates from the scaling relation, exhibiting a vertical trend when T < T c. This discrepancy suggests the occurrence of a first-order phase transition in the crystal under a low magnetic field when T< T c. Mössbauer spectra were employed to provide insights into the critical behaviors of magnetic moments at different sites, including (Fe1)A, (Fe1)B, and Fe2. The results are consistent with the isothermal magnetization analysis. Additionally, the renormalization group theory analysis reveals that the spin coupling within the Fe3.8GaTe2 crystal follows the three-dimensional Heisenberg ({d:n} = {3:3}) type with long-range magnetic and exchange interaction decays with a distance as J(r) ≈ r −4.80.

Research on fusion and deformation analysis of decade' HLS-II control network surveying data

To ensure the long-term stability of the beam and further construction needs, it is necessary to re-measure the particle accelerator regularly. Since 2013, we have been measuring the HLS-II control network with laser trackers and the level for 10 years. Taking HLS-II as the object of study, we introduced the data acquisition strategy for the period of 2013–2023. We analyzed the horizontal and vertical deformation trends of each control point. In the vertical direction, we fused the geometric level and elevation data of the laser tracker network by using MC-GMM (a Gauss-Markov model which considers the uncertainty of Monte Carlo simulation). The analysis results show that, after the HLS upgrade, the annual average settlement of the ground control network tends to be stable. The settlement and horizontal variation of the device are all within a reasonable and controllable range. To ensure stability, accuracy, and efficiency in the measurement, we recommend employing the laser tracker for the re-measurement of the HLS-II storage ring. The data processing flow and methods mentioned in the article can provide a reference for deformation analysis of the upcoming construction of the Hefei Advanced Light Facility (HALF) and other large-scale metrology projects.

Sedimentary facies analysis of a thin-bed-dominated turbidite succession in the Miocene Temburong Formation, Kampung Bebuloh, Labuan Island, Malaysia

Thin-bedded turbidites are important hydrocarbon-bearing reservoirs in many mature fields throughout the world. The type of turbidite depositional setting strongly influences vertical and horizontal continuity of the reservoir. However, distinguishing between lobe and levee associated thin-bedded turbidites remains challenging due to their generally similar facies characteristics. This study aims to contribute some insights to this problem by conducting a detailed bed-scale facies analysis on the Early Miocene Temburong Formation exposed at Kampung Bebuloh, Labuan Island, Malaysia, which may uncover features that can help in differentiating between both depositional types. Six facies are recognized in the Temburong Formation, which are interpreted as low density turbidites (F1–F4), hybrid event beds (F5), and sustained turbidites (F6). Detailed facies and ichnology analysis reveal features which are consistent with a lobe fringe deposit rather than levee-associated environment interpretation, including tabular bed geometries, presence of hybrid event beds, and the absence of thick-bedded channel-fill sandstones. Five facies associations are identified and interpreted as representing sub-environments within an overall lobe depositional setting. A diverse trace fossil assemblage, comprising the Nereites ichnofacies is consistent with a deep marine environment. Further identification of the Paleodictyon and Nereites sub-ichnofacies indicates a distal turbidite system setting, most likely lobe fringe. Based on the thick accumulation of FA2 and FA3 and no distinct observable vertical trend, the Early Miocene Temburong Formation in Labuan is interpreted as turbidites deposited at the fringes of lobe complexes rather than a single lobe fringe. Earlier works into the Temburong Formation in SW Labuan proposed a middle slope to proximal basin floor setting where the thin-bedded intervals were interpreted as potentially representing either levee deposits or the fringes of confined lobe deposits. Conversely, the Temburong Formation at Kampung Bebuloh exhibits characteristics of an unconfined lobe setting, suggesting an evolutionary change in depositional conditions over time.

Unravelling the genetic mechanisms and paleoenvironmental controls of early Cretaceous Oyster Mass occurrences (OMOs), Neuquén Basin, west-central Argentina

Lower Valanginian oyster mass occurrences (OMOs) from the Neuquén Basin of Argentina are analyzed using a multidisciplinary approach, including the description of their sedimentological signature and stratigraphic contacts, assessment of taphonomical attributes, and paleontological and paleoecological characteristics. These OMOs present a wide distribution in the study area, with lateral continuity for at least 2.5 km and up to 12 m thick. They occur within a single stratigraphic interval, constrained in terms of sequence stratigraphy and biostratigraphy. Three stacked tabular OMOs separated by mudstone levels were recorded in all the studied localities. The associated lithofacies point to a mainly outer ramp paleoenvironment, below storm wave base and occasionally disturbed by exceptional, distal storm flows. Internally, the OMOs share a common vertical trend characterized, from base to top, by a gradual increase in oyster abundance and a transition from mainly reclining, disarticulated oysters to articulated, cementing oysters conforming build-ups. Hence, a mainly biogenic origin is proposed, with autobiostromes grading vertically to bioherms. This vertical trend was interpreted in terms of development stages, namely, colonization, expansion, climax and extinction, which were in turn related to specific paleoenvironmental controls. Particularly, the OMOs establishment and development were associated to low sedimentation rates, salinity fluctuations and high nutrient input as a result of high primary productivity. At a larger scale, the overall paleoenvironmental conditions and subtropical geographical position of the basin were detrimental for most reef builders typical of the Cretaceous period (e.g., corals, sponges, rudists), and could have favored oyster proliferation and OMOs development instead.

Modeling the long-range transmission of airborne bioaerosol releases in a high-density urban environment

In this study, the effect of different meteorological conditions in four seasons on the flow field in a high-density urban environment was examined using numerical simulations. The effect of different thermal conditions on bioaerosol dispersion was evaluated. The dispersions of bioaerosol under three leakage scenarios, i.e., far from crowds (Release 1), close to crowds (Release 2), and simultaneous leakage at two locations, were analyzed. The flow field analysis shows that the wind speed is higher during the summer solstice than the other dates in the vertical direction. The concentration field analysis shows that compared with stable thermal conditions, the lateral dispersion range of bioaerosol in unstable thermal conditions is smaller and the dispersion distance is longer. Compared to Release 2, the Release 1 condition exhibits narrower lateral dispersion. In simultaneous releases, while the vertical concentration distribution trends remained unchanged, there were notable variations in concentration levels and dispersion range. The deposition analysis shows ground deposition in building areas surpasses building wall surface deposition across diverse leakage scenarios and meteorological conditions. Additionally, in Release 1, unstable thermal conditions enhance bioaerosol deposition on building walls but reduce it on the ground within the building area, compared to stable thermal conditions.

Quantitative facies analysis of a fluvio-aeolian system: Lower Triassic Buntsandstein Group, eastern France

Understanding the factors that control the temporal and spatial evolution of the Lower Triassic Buntsandstein Group, eastern France, is important not just for palaeoenvironmental reconstruction but also because it is an important reservoir for the lithium-rich geothermal brines in the Upper Rhine Graben region. The interval of interest in this study, the Lower Grès Vosgien Formation (LGV), is made up of c. 200 m of clastic deposits of mixed fluvial and aeolian origin. Given the proximity between the outcrops and the areas of mineral and heat exploration, this region offers a unique opportunity for quantitative analysis and correlation between outcrops and reservoirs. The LGV is the thickest Formation in the Buntsandstein Group. However, hitherto, no detailed architectural analysis has been published to reveal the controlling factors of its depositional elements. In this study, high-resolution facies analysis was applied to thirteen outcrops, and a core, to quantify fluvial and aeolian depositional architectures, and to comprehend palaeoenvironmental conditions during their deposition. Two facies associations were identified. The fluvial channel facies association, composed mainly of sandstones deposited in poorly confined, occasionally ephemeral channels, corresponds to 93 % of the total thickness. The analysis of >800 sets of strata characterised by lower-, transitional-, and upper-flow regime sedimentary structures, distributed within different architectural elements, enabled the distinction of temporal and spatial variabilities, and an estimate of fluvial palaeohydraulic characteristics. The wind- and water-laid facies association, which accounts for 7 % of the total thickness, records an architecture controlled by a fluctuating water-table level, and ephemeral floods. Results revealed that aeolian dunes and sand sheets accumulated in distinct temporal moments. The vertical trends, recorded in the core, indicate an upward increase in the frequency of intercalations between the two facies associations, and a decrease in the occurrences of thicker cross-bedded sandstone sets of fluvial origin, which, associated with the overall retrogradational stacking pattern of the LGV, is interpreted as the preserved record of a large distributive fluvial system (DFS). The occurrence of laterally extensive aeolian deposits, overlying fluvial deposits, is often associated by authors with periods of relatively more arid conditions at a regional scale. However, evidence indicates channel belt avulsion as an alternative interpretation for the establishment of the two facies associations. The findings enhance the knowledge about the depositional controlling factors in braided fluvial and aeolian systems, and improve predictive models that account for reservoir heterogeneity in accumulated successions of this type.

Vertical accretion trends project doughnut-like fragmentation of saltmarshes

Coastal saltmarshes keep pace with sea-level rise through in-situ production of organic material and incorporation of allochthonous inorganic sediment. Here we report rates of vertical accretion of 16 new sediment cores collected proximal to platform edges within saltmarshes located behind four barrier islands along the southeast United States coast. All but two of these exceed the contemporaneous rate of relative sea-level rise, often by a factor of 1.5 or more. Comparison with 80 additional measurements compiled across the Georgia Bight reveals that marshes situated closer to inlets and large bays generally accrete faster than those adjacent to small creeks or within platform interiors. These results demonstrate a spatial dichotomy in the resilience of backbarrier saltmarshes: marsh interiors are near a tipping point, but allochthonous mineral sediment fluxes allow enhanced local resilience along well-exposed and platform-edge marshes. Together, this suggests that backbarrier marshes are trending towards rapid, doughnut-like fragmentation.

Competition effects of vertical integration in container ports: assessing the European Commission decisional practice

PurposeContainer liner shipping companies started expanding their business by investing in container port terminals in the late 1990s. This market entry results in an extensive presence of vertically integrated liners and terminals. This study aims to explore the competition effects of this vertical integration trend based on a regional (European) analysis. In particular, it extracts lessons from the European Commission (EC) cases on the competition effects of vertical integration. The critical analysis of the cases examined at the institutional level intends to reach conclusions on whether liner–terminal vertical integration harmed or advanced competition in the relevant markets and/or the extent that there is a need to revise the current policy practices.Design/methodology/approachThis study critically assesses the EC’s decisional practices in port container terminal vertical mergers in the last 25 years (1997–2021). Based on a literature review comparing maritime and competition economists' perspectives, it reviews the types of mergers examined, the methodology followed for relevant market definition and calculation of market shares and the estimated competition effects. The Hamburg–Le Havre area is the port range used as a case study for comparing the decisional practice with actual market developments. These container ports serve the greatest consuming market of final and intermediate goods in Europe and are gateways to Central and Eastern Europe.FindingsThe assessment identifies a need for expanding the investigation as a precondition for reaching conclusions on both the anti- and pro-competitive effects. First, only a limited number of transactions have been notified to the EC. Second, the empirical research identified a gap in this process, as there were no decisions (phase I) on vertical mergers between 2008 and 2016. Third, the exante assessment has not applied a phase II in-depth analysis to any case due to the absence of competition concerns. Finally, due to the absence of complaints, there is a lack of any ex post assessment of the effects of vertical integration.Research limitations/implicationsThis assessment is important for understanding the current and emerging features of intra-port and inter-port competition and the potential effects that the continuation and expansion of liner companies' vertical integration strategies will have along maritime supply chains. It also contributes to the broader discussion on liner companies' strategies, such as the research and policy-making efforts around the globe to understand the impact of both vertical and horizontal integration.Practical implicationsThese discussions are critical for a diversity of businesses that use liner shipping services or provide facilities and services to container shipping lines or ports. They are important for the interests of customers and consumers as they could inform any needed re-visiting of competition policy to protect from the dominance of any market developments that would lead to conditions limiting competition. Expanding analysis on the competition effects of non-notified mergers would help a better understanding of market changes.Social implicationsEnhancing competition and limiting monopolies is valuable from a consumer's perspective. This is more so in the case of maritime trade that serves the needs of societies. The study contributes by generating a better understanding of how decision-makers have worked towards that direction and what realignments are worthy.Originality/valueThere are no previous comprehensive reviews and analyses of the ways that policy-makers at the regional level have addressed the competition effects of vertical integration strategies of liner shipping companies when enhancing competition is valuable from a consumer perspective. Comparing maritime economists and competition, the study, via its literature review, also offers a comparison of maritime and competition perspectives on these competition effects, allowing positioning of how effective decisional-making practices have been.

A Novel Method for Analyzing the Spatiotemporal Characteristics of GNSS Time Series: A Case Study in Sichuan Province, China

The motion of a continuously operating reference station is usually dominated by the long-term crustal motions of the tectonic block on which the station is located. Monitoring changes in the coordinates of reference stations located at tectonic plate boundaries allows for the calculation of velocity fields that reflect the spatial and temporal characteristics of the region. This study analyzes the spatiotemporal relationships of regional reference frame points with GNSS data from 25 reference stations in Sichuan, China, from 2015 to 2021. The common mode errors are extracted and eliminated by principal component analysis. A time series function model is developed for the reference stations and their constituent baselines for calculating the velocity field. Subsequently, the spatiotemporal characteristics of the regional reference frame in Sichuan is analyzed by a stochastic model. The results show that the influences of the common mode error on the horizontal and vertical directions of the reference stations is 2.5 mm and 4.3 mm, respectively. Generally, the horizontal motion of the reference stations in the Sichuan region tends to be in the southeast direction and the vertical motion trend is mainly uplifting. The east–west and vertical components of the baseline tend to be shortened, and the random influence among the reference stations is larger in the north–south and east–west directions—0.39 mm and 0.54 mm, respectively. Polynomial functions are more appropriate for constructing the fitted random influence covariance model.

Geochemical characterization and implications of soil gas and geothermal fluids in the fault zone of Xiongan new area

This study investigates the geochemical characteristics and implications of soil gas and geothermal fluids in the fault zone of Xiongan New Area (XNA). Spatial distribution analysis reveals high soil gas concentrations along the fault zone, prompting the establishment of measurement lines along specific fault segments, such as Niudong fault, with a vertical burial trend. The measured average Rn flux ranges from 71.44 to 335.35 mBq m−2s−1, while CO2 flux ranges from 25.96 to 78.23 g m−2d−1. Furthermore, the average Rn and CO2 concentration intensities range from 0.91 to 2.30 and 1.13 to 2.61, respectively, indicating significant degassing in the fault zone.Geothermal well samples are collected from the deep reservoir in XNA, displaying a predominance of Cl–Na composition. Analysis of the Na–K–Mg equilibrium diagram suggests that the chemical characteristics of deep geothermal water are a result of interactions with rocks and mixing with shallow cold water in XNA. Isotopic analysis indicates the atmospheric precipitation origin of the deep geothermal water with extensive lateral recharge from underground runoff, emphasizing strong water-rock interactions. Comparison with other tectonic units in the region reveals that the Niudong Fault Zone serves as a regional geothermal control structure, facilitating deep fluid convection.In the eastern part of XNA, the geochemical analysis reveals concentrated degassing and a relatively high proportion of mantle-derived sources near the Niudong Fault Zone. This observation suggests the fault zone serves as a primary conduit for deep gases and geothermal fluids. The findings of this research provide valuable scientific references for future urban planning, energy utilization, and geologic hazard monitoring in XNA. Continued monitoring efforts are crucial for understanding the nature of fault activity and resource distribution in the region.

Assessment of Oceanographic Trend and Ocean Health Index in The Gulf of Madura

The Gulf of Madura is heavily utilized for shipping, fishing, and oil exploration. These activities impact the marine environment. This study aims to describe the spatial and temporal variability in oceanographic parameters, vertical current structures, trends, and ocean health conditions based on oceanographic parameters estimated from the OHI value. The data used in this research consists of INDESO and Marine Copernicus data. The results of the study show that monsoon phenomena greatly influence temperature and salinity in the Gulf of Madura, with temperature increasing and salinity decreasing during the northwest monsoon, and vice versa during the southeast monsoon. An analysis of oceanographic variables over the past 12 years showed an increase in salinity and nitrate variables, and a decrease in other variables. The trend fluctuation is still within the quality standard for seawater according to government regulation number 22 of 2021. The results of the calculation of the ocean health index show that the Gulf of Madura is in a fair condition with a value of 0.63. This finding can be used to manage and utilize marine space sustainably without deteriorating the ocean’s health.

Response of soil erosion to climate change and vegetation restoration in the Ganjiang River Basin, China

In the context of global warming it remains challenging to evaluate declining of soil erosion due to ecological engineering measures, and to isolate and quantify the contributions of various factors involved in soil erosion. For this study, soil erosion and soil conservation dynamics in the Ganjiang River Basin (GRB) in southeast China were quantitatively assessed based on the Integrated Ecosystem Services and Tradeoff Assessment (InVEST) model. Based on the analysis of the attribution factors of precipitation and Fractional Vegetation Cover (FVC), the dominant factors involved in soil erosion were determined by scenario comparison, where the areas with high sensitivity to erosion were quantitatively identified. The results revealed that both simulated value of soil erosion and sediment export initially decreased and then increased from 2000 to 2020; however, the total increases over the last 20 years were 14 % and 18.18 %, respectively. Moreover, the erosion intensity and sediment delivery ratio (SDR) decreased due to the influence of engineering measures such as reservoirs. Precipitation was the dominant factor that affected GRB soil erosion, with its contribution ratio (40 %-60 %) being as high as 94.74 %. In other words, in the GRB, precipitation inhibited the mitigation effect of high vegetation cover on soil erosion, and the contributions of FVC and precipitation showed a vertical trend. The extremely sensitive area caused by FVC is situated in the economically developed cities along the river system in the middle portion of the basin, while the extremely sensitive area caused by precipitation resides in the middle and upper reaches of the western portion of the basin. Based on this, prioritized protection areas can be determined.

Variability of rare earth and heavy metal elements in a representative alluvial depositional system.

Heavy metals (Ni, Cr, W, Cd, and Pb) and rare earth elements (REE) were investigated in the flood plain sediments of an island of the lower Yangtze River near Nanjing to determine how the vertical distribution of heavy metals could be affected by natural sedimentation processes and anthropogenic contamination. Stratigraphic analyses of magnetic susceptibility and the mean grain size distribution of the deposits enabled us to identify layers associated with a relatively high influx of suspended sediments that resulted in sudden changes in the concentrations of heavy metals. The results show that layers associated with high sediment influx (0.8m depth) displayed low concentrations of Cr, Ni, W, and Cd that were mainly lithogenic in origin. The Post Archean Australian Shale (PAAS) normalized REE patterns in the flood plain cores were enrichment in Ce and Eu relative to PAAS, indicating that the sediments were most likely derived from a mixture of sediments and not from an anthropogenic source. Sharp increases in Y/Ho ratios, as well as heavy metal (Cd, Cr, Ni, and W) and Y concentrations were observed in the uppermost layer that could have been deposited from the rapid transport of sediment-laden, contaminated waters. The temporal (vertical) trends in Pb concentrations may be strongly influenced by coal burning. Elevated Pb concentrations (350ppm and 1000ppm) correlate with high magnetic susceptibility (> 200 m3 × kg-1) and the history of thermal power plant (1910-2002) activity. The anthropogenic inputs of Pb were, however, not diluted by high suspended sediment loads, which supports the argument that Pb was derived from fly ash.