Changes In Flux Research Articles

Interannual Variability and Trends in Extreme Precipitation in Dronning Maud Land, East Antarctica

This study examines the trends and interannual variability of extreme precipitation in Antarctica, using six decades (1963–2023) of daily precipitation data from Russia’s Novolazarevskaya Station in East Antarctica. The results reveal declining trends in both the annual number of extreme precipitation days and the total amount of extreme precipitation, as well as a decreasing ratio of extreme to total annual precipitation. These trends are linked to changes in northward water vapor flux and enhanced downward atmospheric motion. The synoptic pattern driving extreme precipitation events is characterized by a dipole of negative and positive height anomalies to the west and east of the station, respectively, which directs southward water vapor flux into the region. Interannual variability in extreme precipitation days shows a significant correlation with the Niño 3.4 index during the austral winter semester (May–October). This relationship, weak before 1992, strengthened significantly afterward due to shifting wave patterns induced by tropical Pacific sea surface temperature anomalies. These findings shed light on how large-scale atmospheric circulation and tropical-extratropical teleconnections shape Antarctic precipitation patterns, with potential implications for ice sheet stability and regional climate variability.

Estimation of Radon Flux Density Changes in Temporal Vicinity of the Shipunskoe Earthquake with Mw = 7.0, 17 August 2024 with the Use of the Hereditary Mathematical Model

Using the data of radon accumulation in a chamber with excess volume at one of the points of the Kamchatka subsurface gas-monitoring network, the change in radon flux density due to seismic waves and post-seismic relaxation of the medium is shown. A linear fractional equation is considered to be a model equation. The change of radon-transport intensity due to changes in the state of the geo-environment is described by a fractional Gerasimov–Caputo derivative of constant order. Presumably, the order of the fractional derivative is related to the radon-transport intensity in the geosphere. Using the Levenberg–Marquardt method, the optimal values of the model parameters were determined based on experimental data: air exchange coefficient and order of fractional derivative, which allowed the solving of the problems of radon flux density determination. Data in the temporal neighborhood of a strong earthquake with Mw=7.0, which occurred in the northern part of Avacha Bay on 17 August 2024, were used. As a result of the modeling, it is shown that the strong seismic impact and subsequent processes led to changes in the radon flux in the accumulation chamber. The obtained model curves agree well with the real data, and the obtained estimates of radon flux density agree with the theory.

Revisiting the Inconsistent Influence of El Niño–Southern Oscillation on the Equatorial Atlantic

Abstract The impact of El Niño–Southern Oscillation (ENSO) on the equatorial Atlantic zonal mode (AZM) is investigated using two atmospheric reanalysis products and 44 models from phase 6 of the Coupled Model Intercomparison Project (CMIP6). While the impact of ENSO on equatorial Atlantic SST is inconsistent, as previously reported, there is a very robust influence of decaying ENSO events in boreal spring on the contemporaneous surface zonal winds over the equatorial Atlantic, with El Niño events associated with anomalous easterlies that cool the equatorial Atlantic. This dynamic impact is counteracted by a thermodynamic impact, in which El Niño events cause changes in surface heat fluxes that lead to warming over the tropical Atlantic. The thermodynamic influence is active throughout the life cycle of the ENSO event, but the dynamic influence is highly seasonal with a pronounced peak in boreal spring. Thus, a quickly decaying El Niño event will lead to warming, while a slowly decaying event will lead to cooling in the equatorial Atlantic. The ENSO–AZM relation is further complicated by partially independent Atlantic variability, in particular that associated with the South Atlantic subtropical dipole (SASD). Prediction experiments with a simple linear regression model support the role of the SASD as an AZM precursor. Many CMIP6 models show skillful predictions of the June–August AZM based on SST indices in the preceding December–February, with correlations above 0.5. When predictions are restricted to ENSO years, even more models exceed this threshold, but skill in the reanalyses remains relatively low, possibly due to insufficient training data. Significance Statement El Niño is the strongest climate signal on interannual time scales. Its influence on the equatorial Atlantic, however, is surprisingly inconsistent. Here, we show, using an ensemble of climate models and observation-based data, that El Niño has a very robust influence on equatorial Atlantic surface winds, but only in boreal spring. This leads to a large difference in how El Niño events influence the equatorial Atlantic, based on how quickly they decay in boreal spring. We also find that variability in the South Atlantic, which is partly independent of El Niño, has a strong influence on the equatorial Atlantic, supporting the result of previous studies. These findings suggest that the predictability of equatorial Atlantic temperature anomalies may be higher than previously thought.

Angelica sinensis polysaccharide as potential protectants against recurrent spontaneous abortion: focus on autophagy regulation

IntroductionRecurrent spontaneous abortion (RSA) represents a significant clinical challenge, with its underlying mechanisms yet to be fully elucidated. Despite advances in understanding, the precise pathophysiology driving RSA remains unclear. Angelica sinensis, a traditional herbal remedy, is frequently used as an adjunctive treatment for miscarriage. However, it remains uncertain whether its primary active component, Angelica sinensis polysaccharide (ASP), plays a definitive role in its therapeutic effects. The specific function and mechanism of ASP in the context of RSA require further investigation.MethodsIn this study, we sought to evaluate autophagy levels at the maternal-fetal interface in RSA patients and in an RSA mouse model treated with ASP, complemented by a comprehensive metabolomic analysis. Autophagy flux in the decidua was compared between eight RSA patients and eight healthy pregnant women. Additionally, changes in autophagy flux were assessed in an RSA mouse model following ASP treatment, with embryos and placental tissues collected for subsequent metabolomic profiling.ResultsOur results revealed a significant reduction in Beclin 1 protein levels in the decidua of RSA patients compared to the normal pregnancy group. Conversely, ASP treatment in the RSA mouse model restored autophagy-related protein expression, including ATG7, ATG16L, and Beclin 1, to levels higher than those observed in the untreated RSA group. Metabolomic analyses further identified significant changes in phosphatidylethanolamine levels between ASP-treated and control groups, with differential metabolites enriched in pathways related to glycolysis/gluconeogenesis, glycerolipid metabolism, and glycine, serine, and threonine metabolism. Functional assays revealed that ASP enhances trophoblast cell proliferation, migration, and invasion.ConclusionIn summary, our findings demonstrate diminished autophagy activity in RSA patients, while ASP appears to restore autophagy and regulate key metabolic pathways, including glycolysis/gluconeogenesis. These results provide new insights into the protective mechanisms of ASP in RSA, suggesting its potential as a therapeutic intervention for this condition.

Modelling of ETG turbulent transport in the TCV pedestal

Abstract Results of the first gyrokinetic simulations of the TCV pedestal are presented. Two discharges at varying levels of gas puffing are considered as input parameters for the local GENE simulations. Linear and nonlinear simulations are carried out for electron scale turbulence to determine the role of the Electron Temperature Gradient (ETG) mode in the pedestal transport. The heat flux associated with ETG is found to be negligible compared to the total experimental electron heat flux at lower gas puff. At higher gas puff, computed heat flux was find to account for experimental values, demonstrating the importance of the ETG-driven transport in this case.
Additional simulations are carried out with modified density profiles to investigate the difference between the two discharges. The change of the electron heat flux is found to be associated with the transition from slab- to toroidal-ETG due to the reduction of the normalized density gradient in the pedestal at the higher gas puffing.

Thermal Design and Experimental Validation of a Lightweight Microsatellite

The multiple working modes, complex working conditions, frequent changes in external heat flux, and high-power consumption of satellites all pose great difficulties to their thermal design. In this paper, the material MB15 magnesium alloy was used, which has not been performed for the main structure of satellites. This material not only reduces the weight of the structure and the launch cost, but also its good thermal conductivity is very helpful for the thermal control design of the satellite. This paper mainly describes the design of a thermal control system for lightweight microsatellites. Firstly, the satellite structure, thermal control indices of the main equipment, and the power consumption of the equipment in different working modes are introduced. Then, the external heat fluxes are analyzed, the position of the heat dissipation surface and extreme conditions are confirmed, and detailed thermal designs of each part of the satellite are determined via the combination of active and passive thermal control. Finally, the thermal balance test is carried out for the whole satellite. It is found that the deviation between the temperature of the thermistor and thermocouple at the same moment in the thermal analysis simulation data and thermal balance test is generally within 0.5 °C, and the maximum difference is not more than 1.7 °C, which indicates that the simulation model is well established and that the thermal analysis is reliable.

Highly selective copper recovery from industrial wastewater via electric field-enhanced ultrafiltration assisted with a picolyl-modified polyelectrolyte.

Copper-containing industrial wastewater, characterized by strong acidity, high ionic strength, and various competing metals, presents significant challenges for Cu(II) recovery. To address these issues, an electric field-enhanced ultrafiltration process was developed, assisted with a functional polyelectrolyte with high selectivity for Cu(II). The polyelectrolyte, termed PPEI, was synthesized by grafting picolyl groups onto polyethyleneimine (PEI), enhancing its affinity for Cu(II). The captured Cu(II) was subsequently recovered through electrolysis, demonstrating a sustainable approach for both Cu recovery and PPEI recycling. The synthesis and stability of PPEI were confirmed through infrared spectroscopy, particle size analysis, and dialysis validation, ensuring its reliability in practical applications. The incorporation of picolyl groups onto PPEI enhances its selectivity for Cu(II) via coordination with two amines and four pyridyl groups per copper ion. Under acidic conditions, the maximum loading ratio of copper to PPEI is 1:4 with loading capacity of 119.4 mg/g, which increases to 1.5:4 (i.e., 179.1 mg/g) under neutral to alkaline conditions due to the deprotonation of excess amines. PPEI effectively removes Cu(II) from solutions under various harsh conditions at the loading ratio of 4, maintaining 92-98 % removal efficiency in the presence of high salt concentrations (up to 1 M NaCl) and pH as low as 1, and approximately 85 % removal in solutions with competing metal ions at concentrations up to 50 times higher than Cu(II). Scanning electron microscopy and membrane flux changes indicated that the application of a positive electric field significantly reduces membrane fouling and enhances Cu(II) selectivity. The application of a +0.2 V voltage to the membrane side reduced the flux decline rate by 58 %, significantly improving membrane performance while maintaining a Cu(II) removal efficiency of over 95 %. Electrolysis optimized at a current density of ≤0.004 A/cm2 achieved an 80 % copper recovery while allowing PPEI to be released for recycling. Tests conducted using two types of real industrial wastewater demonstrated a copper removal rate of ∼95 %, with a recovery rate of ∼80 %. This study provides a novel and highly selective approach for the efficient recovery of valuable metals from industrial wastewaters.

Distribution and controlling factors of dissolved inorganic carbon in urban rivers of a North China megacity: Insights from δ13CDIC.

Transportation and transformation of the dissolved inorganic carbon (DIC) play a critical role in the regional carbon cycle. To clarify the natural and anthropogenic impacts on DIC, the concentration and isotopic composition of DIC (δ13CDIC) in two typical urban rivers in northern China (Yongding River, YDR, and Chaobai River, CBR) were measured. Mass-balanced calculations were employed to quantify the impacts of different weathering processes. The results indicated that carbonate weathering under the influence of mixed weathering agents was the primary weathering process in the YDR and CBR. Carbonate dissolution by carbonic acid was an important source of DIC in both the YDR and the CBR. According to the end-member calculations of δ13CDIC, soil-respiration CO2 was a key factor controlling the carbonate weathering by carbonic acid. A high contribution of sulfuric and nitric acids to carbonate weathering was found in the YDR, especially in downstream areas with high-level anthropogenic activities. This indicated that anthropogenic activities can profoundly impact the weathering processes in watersheds. This study provides insights into the complex interactions between human activities and natural processes in shaping the carbon dynamics of urban rivers, highlighting the importance of natural and anthropogenic factors on carbon dynamics in urban rivers and providing insights essential for predicting carbon flux changes amidst urbanization and climate change.

Eutrophication triggered changes in network structure and fluxes of the Comacchio Lagoon (Italy).

Coastal lagoons, which cover about 13% of coastline, are among the most productive ecosystems worldwide. However, they are subject to significant stressors, both natural and anthropogenic, which can alter ecosystem services and functioning and food web structure. In the Comacchio Lagoon (Northern Italy), eutrophication, among other minor factors, transformed the ecosystem in the early 1980s. Here, we compiled available data for the lagoon into trophic networks (pre- and post-transformation), analyzed the ecosystem using local and global network analysis, and computed trophic fluxes of the two periods. For comparability, the networks of two periods (i.e., pre- and post- transformation) were aggregated into food webs with 23 nodes. We found differences in the trophic networks before and after eutrophication, resulting in some decrease in complexity, increase of flow diversity, and an overall shortening of the food chain. A crucial aspect of this change is the disappearance of submerged vegetation in the lagoon and the increased importance of cyanobacteria in the post-eutrophication period. We provide an approach to better understand ecosystem changes after severe disturbances which can be extended to biodiversity conservation and for the management of coastal resources in general.

Evolution of eruption rate between two caldera-forming eruptions in the Jemez Mountains volcanic field, New Mexico, USA

Rhyolites that erupted between the Otowi and Tshirege members of the Bandelier Tuff, known as the Valle Toledo Member, were investigated in the Jemez Mountains volcanic field to infer changes in eruptive rate and flux between two caldera-forming eruptions. Our analysis combines high-precision 40Ar/39Ar single-crystal laser-fusion dating of sanidine, matrix glass compositions and mineralogy of pumice, depositional textures, and volumetric estimates of erupted rhyolites to present a revised Valle Toledo Member eruptive chronology that integrates our observations with those of previous studies. With the improved temporal resolution of our high-precision eruption ages (median 2σ uncertainty of ±2.9 ka), the updated Valle Toledo Member eruption chronology consists of at least 42 temporally or mineralogically distinct eruptions that we group into four periods of time based on eruption rate. Within the first 8.1 ± 5.1 kyr (~1605–1597 ka) that followed the Otowi caldera-forming eruption at 1605.4 ± 2.3 ka, six eruptions are recognized. This suggests an average recurrence interval on the order of 1.4 ± 0.9 kyr. Twenty-seven eruptions occurred during the next 194.4 ± 5.1 kyr (from ~1597–1403 ka) and the average recurrence interval increased to 7.2 ± 0.2 kyr. Following this second period of slower eruption rate, a previously unrecognized eruption hiatus of up to 162.4 ± 3.1 kyr occurred from 1402.9 ± 2.3 ka to 1240.5 ± 2.1 ka. Resumption of volcanic activity is characterized by a series of at least nine volcanic eruptions during the next 8.6 ± 2.5 kyr, culminating in the eruption of the 400 km3 Tshirege Member of the Bandelier Tuff and formation of Valles caldera at 1231.9 ± 1.3 ka. This last phase of pre-caldera activity has the shortest observed average recurrence interval (1.0 ± 0.3 kyr) and greatest eruptive flux (≥ 0.4 ± 0.2 km3/kyr) that occurred between the two caldera-forming eruptions. We interpret the shifts in eruption rate and flux following the 162.4 ± 3.1 kyr eruption hiatus, in addition to mineralogical changes present in post-hiatus rhyolites, as indicators that the Bandelier system was trending towards another major eruption. The magmatic system may have grown gradually throughout the ca. 162 kyr period of volcanic repose; however, the heightened eruption rate in the ca. 10 kyr before caldera collapse is consistent with relatively rapid growth of the magmatic system before the Tshirege event as previously proposed by other studies. Furthermore, the new dataset is consistent with prior geochronology studies of the region that show the four largest explosive eruptions in the Jemez field were all proceeded by very slow eruptive rates or hiatuses. This demonstrates that sequences of heightened volcanic activity can initiate on rapid geological timescales from states of volcanic quiescence in the Bandelier system.

Spatiotemporal variability of air-sea CO2 fluxes in response to El Niño-related marine heatwaves in the tropical Pacific Ocean.

The tropical Pacific is the largest oceanic source of carbon dioxide (CO2) emissions, where persistent marine heatwaves (MHWs) frequently occur. During persistent MHW events which are associated with strong El Niño events, CO2 outgassing is notably reduced, however, its detailed spatiotemporal response to MHWs has not been fully characterized. In this study, we showed a high degree of consistency between CO2 source regions in the central and eastern tropical Pacific Ocean and the occurrence regions with average annual MHW days exceeding 45 days (co-occurring area covers 80% of the area where MHWs occur). The spatiotemporal variability of the air-sea CO2 flux on interannual and longer timescales can be reconstructed from annual MHW days and occurrence frequency, respectively, in the central and eastern Pacific Ocean of the co-occurring region. In this region, El Niño-related MHWs reduce the air-sea CO2 flux density up to 0.4-0.8 molC/m2/yr per 100 MHW days, corresponding to a reduction of CO2 emissions by approximately 0.1 PgC per 100 MHW days. This is a 10%-40% reduction in CO2 emissions during MHW periods, with the strongest impact (30%-40% CO2 emission reduction) in the equatorial Pacific (5°S-5°N) of the central and eastern Pacific Ocean. In contrast, air-sea CO2 flux variations in coastal eastern upwelling region of the co-occurring region are mainly subjected to seasonal mixed layer variations, and thus not notably affected by El Niño-related MHWs on interannual timescales. By establishing the reproducibility between MHWs and air-sea CO2 flux variations, our results pave a way for detailed future spatiotemporal evolutions of MHW-induced changes in air-sea CO2 flux in the tropical Pacific Ocean.

Reliability assessments of using different heavy metals from remote sediment records to reconstruct historical pollution.

Interpreting heavy metal variations in sedimentary records is an important approach to understand historical pollution. However, few studies have investigated the reliability of different heavy metals in sedimentary records for reconstructing historical pollution. This study retrieved two adjacent lakes' sediment cores from a remote area in North China and investigated their temporal changes in excessive metal fluxes. Combined with a novel index of the ratios of atmospheric emissions of anthropogenic metals to background metal values in lake sediments, the reliability and influencing factors of eight metals (Cr, Co, Ni, Cu, As, Zn, Cd, and Pb) in sediments to reconstruct historical pollution were studied. Vertical As variations in the sediments were controlled mainly by early diagenesis effects, although anthropogenic pollution might also have had an impact. Consequently, As profiles in lake sediment records are usually difficult to reflect historical pollution. (2) Among the eight metals, Zn, Cd, and Pb in both lakes have been affected mainly by human pollution and insignificantly by natural factors. Their excessive flux variations in the two records were highly consistent with the historical trend of economic/industrial development. Relatively, these three metals can reliably reflect historical pollution. (3) Compared with Zn, Cd, and Pb, Cr, Co, Ni, and Cu in the two lakes have been relatively less affected by anthropogenic pollution. During the period of relatively high anthropogenic metal emissions (post-∼1980), they could roughly reflect historical pollution in the region; however, during the period of relatively low emissions (before ∼1980), they appeared to exhibit no signs of pollution. This suggests the complexity of using them in remote records to reconstruct historical pollution. The importance of this study lies in its potential to provide critical guidance for the use of aquatic sediment records from relatively remote areas in reconstructing the historical metal pollution.

Changes in Water and Carbon Fluxes in the USA Southern Great Plains Grassland Due to Evergreen Forest Encroachment

The southern Great Plains (SGP) grassland of the United States has been largely encroached by evergreen forest in recent decades. The response of the grassland water and carbon cycles to the encroachment is not clear yet. Given so, this study quantified the changes in gross primary production (GPP), evapotranspiration (ET), and ecosystem water use efficiency (EWUE) between grassland pixels with evergreen forest encroachment and neighboring pure grassland pixels (500 m). We also assessed the spatial variation of the changes in relation to precipitation (mm), air temperature (°C), and evergreen forest coverage (%). These analyses were repeated, respectively for the years of 2004, 2008, 2016, and 2019 as robustness check. Results suggest that across the 4 years, 62–72% of encroached grassland pixels exhibit higher annual GPP, 67–74% exhibit higher annual ET, whereas 65–71% exhibit lower annual EWUE. The change ratio of ET is positively correlated with that of GPP but negatively correlated with that of EWUE. Additionally, the spatial variation in the change ratios of annual GPP and ET can be explained to a certain degree by the encroachment amount. These results further clarify the response of water and carbon cycles to evergreen forest encroachment in the SGP grassland.

Preventing excessive autophagy protects from the pathology of mtDNA mutations in Drosophila melanogaster

AbstractAberration of mitochondrial function is a shared feature of many human pathologies, characterised by changes in metabolic flux, cellular energetics, morphology, composition, and dynamics of the mitochondrial network. While some of these changes serve as compensatory mechanisms to maintain cellular homeostasis, their chronic activation can permanently affect cellular metabolism and signalling, ultimately impairing cell function. Here, we use a Drosophila melanogaster model expressing a proofreading-deficient mtDNA polymerase (POLγexo-) in a genetic screen to find genes that mitigate the harmful accumulation of mtDNA mutations. We identify critical pathways associated with nutrient sensing, insulin signalling, mitochondrial protein import, and autophagy that can rescue the lethal phenotype of the POLγexo- flies. Rescued flies, hemizygous for dilp1, atg2, tim14 or melted, normalise their autophagic flux and proteasome function and adapt their metabolism. Mutation frequencies remain high with the exception of melted-rescued flies, suggesting that melted may act early in development. Treating POLγexo- larvae with the autophagy activator rapamycin aggravates their lethal phenotype, highlighting that excessive autophagy can significantly contribute to the pathophysiology of mitochondrial diseases. Moreover, we show that the nucleation process of autophagy is a critical target for intervention.

Method for estimating the highest specific methane flux from the surface of reservoirs

The paper summarizes the results of the database of changes in the specific methane flux at various types of water reservoirs in Russia, in which the authors participated. Measurements were carried out by the method of “floating chambers” in different periods of the annual hydro-ecological cycle. Comparison of the obtained data with the results of foreign experience is given. An approach to parameterization of specific methane flux for calculating the maximum possible methane emission from artificial reservoirs when developing quantitative quotas of greenhouse gas emissions is proposed. The estimation both in different phases of regime (stratification, homothermia) and for separate morphological parts of reservoirs differing in depth is offered.

Simultaneous noninvasive quantification of redox and downstream glycolytic fluxes reveals compartmentalized brain metabolism.

Brain metabolism across anatomic regions and cellular compartments plays an integral role in many aspects of neuronal function. Changes in key metabolic pathway fluxes, including oxidative and reductive energy metabolism, have been implicated in a wide range of brain diseases. Given the complex nature of the brain and the need for understanding compartmentalized metabolism noninvasively in vivo, new tools are required. Herein, using hyperpolarized (HP) magnetic resonance imaging coupled with in vivo isotope tracing, we develop a platform to simultaneously probe redox and energy metabolism in the murine brain. By combining HP dehydroascorbate and pyruvate, we are able to visualize increased lactate production in the white matter and increased redox capacity in the deep gray matter. Leveraging positional labeling, we show differences in compartmentalized tricarboxylic acid cycle entry versus downstream flux to glutamate. These findings lay the foundation for clinical translation of the proposed approach to probe brain metabolism.

On the gravity dynamics of objects in space and time

Existing theories of gravity encompass Newton's law of universal gravitation and Einstein's general relativity; however, they fail to fully elucidate the nature of gravity and the mechanisms by which it influences the motion of objects. This article presents a new gravitational theory model proposed by the author, introducing the concept of gravitational line flux. By employing mathematical methods such as Gauss's theorem and Stokes's theorem, the study investigates how variations in gravitational flux through a closed spatial surface affect the motion of objects. The following laws are proposed: (1) The gravitational flux through a closed surface is directly proportional to the mass m of the enclosed celestial body. (2) Changes in gravitational flux through a semiclosed surface in the direction of an object's motion alter the object's motion state in space, while concurrently, the object's motion induces variations in the gravitational flux through the surface. (3) The time variation increment of gravitational flux through a semiclosed surface in the direction of the object's motion is proportional to the object's acceleration. Furthermore, the motion equations of gravitational fields for celestial bodies or matter in local inertial and noninertial frames are derived.

Ecological and environmental effects of global photovoltaic power plants: A meta-analysis.

The construction of photovoltaic power plants (PVPPs) globally not only mitigates climate change but also exerts various impacts on terrestrial ecosystems. A comprehensive exploration of the intensity of PVPPs on the ecological environmental elements of terrestrial ecosystems, as well as their regulatory mechanisms, is an urgent scientific issue that must be addressed within the context of carbon balance. In this study, we conducted a meta-analysis to investigate the soil, climate, and biological effects of PVPPs construction, as well as changes in ecosystem CO2 fluxes. Our analysis synthesized data from 42 original studies encompassing over 4300 observations. Findings revealed that a significant reduction in wind speed and soil temperature within the photovoltaic field, with average changes of -63.55% (confidence intervals (CI): [-70.77, -56.32]) and -9.72%, CI [-18.51, -0.93], respectively. Concurrently, there was an average increase of 301.63%, CI [14.14, 589.13] in soil moisture content and gross primary productivity, and 28.52%, CI [14.29, 42.75], respectively. However, no significant effects were observed on other ecological environmental factors. Both the random forest model and mixed effects model highlighted key driving factors such as air temperature and humidity, location under the photovoltaic panel, monthly variations, geographical environment, and photovoltaic scale, which influenced the ecological responses to PVPPs. Furthermore, statistical cluster analysis demonstrated that the thresholds of key driving factors will significantly affect the response of ecological environment factors to PVPPs. This study enhances our comprehension of the ecological and environmental implications of PVPPs construction and offers valuable insights for policymakers aiming to implement 'photovoltaic+ecological' integrated management strategies.

Long-term variations in peak electron density and temperature of mesopause region: Dependence on solar, geomagnetic, and atmospheric activities, long-term trends

The paper overviews the main results of the study of long-term variations in characteristics of the upper neutral atmosphere and ionosphere, obtained during the implementation of Russian Science Foundation Project No. 22-17-00146 “Experimental and theoretical study of the coupling neutral and ionized components of Earth’s atmosphere”. We study and compare long-term variations in the peak electron density and temperature of the mesopause region. Their dependences on solar, geomagnetic, and atmospheric activity, as well as long-term trends, are analyzed. The analysis is based on data from long-term measurements with the ISTP SB RAS complex of instruments. The peak electron density (NmF2) data was acquired with the Irkutsk analog automatic ionospheric station for 1955–1996 and the Irkutsk digital ionosonde DPS-4 for 2003–2021. The atmospheric temperatures at mesopause altitudes (Tm) were obtained from spectrometric observations of the hydroxyl molecule emission (OH (6-2) band, 834.0 nm, emission maximum height ~87 km) for 2008–2020. The analysis uses solar (F10.7) and geomagnetic (Ap) activity indices, as well as data on variations in the Southern Oscillation Index (SOI). The study employs simple and multiple linear regression methods. Annual average NmF2 values are found to be predominantly controlled by changes in solar flux. Analysis of regression residuals shows that the largest deviations from regression (for both simple and multiple regression) are observed in years near the maxima of solar cycles 19 (1956–1959) and 22 (1989–1991). Annual average temperature variability in the mesopause region correlates with changes in the SOI index: day-to-day variability exhibits a positive correlation with SOI; and intra-diurnal variability, a negative correlation with SOI. No significant relationship was found between year-to-year variations in the NmF2 and Tm variability.

Tracking the Changes of DOM Composition, Transformation, and Cycling Mechanism Triggered by the Priming Effect: Insights from Incubation Experiments.

The priming effect (PE) is recognized as an important mechanism influencing organic matter transformation in aquatic systems. The land-ocean aquatic continuum (LOAC) has received large quantities of dissolved organic matter (DOM) from various sources, which is an ideal interface for PE research. Here, we investigated the PE process by utilizing such a coastal environment to explore the turnover of DOM in the LOAC system. Suwannee River natural organic matter was selected as the background, and various external environmental samples were introduced to track the changes of organic carbon. The PE process together with the variations of DOM sources, compositions, and structures was characterized. Generally, river and estuary environments exhibited a positive PE, while the offshore zone showed a negative effect. Additionally, nutrients, salinity, and DOM composition all contributed to the PE. After the incubation, the feature of carbon sources transferred from terrestrial to autochthonous. The carbonyl and alcohol functional groups significantly decomposed, while the methyl and methylene groups increased and heteroatoms further accelerated the PE process. The data also shows that special parameters and molecular markers can be utilized to track the carbon response to the PE. This research indicates that the change of carbon flux and the imbalance of its budget in aquatic systems could be partially explained from the perspective of the PE.