bluuebunny/crossref_metadata_2025 huggingface dataset:
Effectiveness of erosion control covers on soil quality recovery, runoff, and sediment production after forest restoration in a fly-ash landfill
Authors: Crovo Oscar , Montecino Francisco , Alvarez Enzo , Aburto Felipe
Published: March 2021

Despite the efforts to reducing residues derived from thermal power stations, as near as 70% of fly-ash and other wastes end up in landfills. Definitive landfill covers are generally limiting for native plant establishment as these materials lack the characteristics of functional soils. This could compromise the success of restoration efforts increasing the risk of erosion. As part of a restoration project, we tested the efficacy of different erosion control covers to enhance soil functions, including C and nutrient cycling, water regulation, and erosion control. First, the fly-ash was encapsulated and covered with a one-meter of sandy-clay sediment mixed with 20 cm pine bark compost. Five native tree species were planted in four plots considering different soil cover treatments (Hydro-mulch, Coconut fiber mulch, Seeded mixed grasses, and no-cover). These were established considering a complete block design with nine replicates for cover treatment. To elucidate what soil function responded more rapidly to these treatments, we measured chemical soil indicators (C, N, and P total and available pools, pH, EC, CEC), microbial (Biomass and C, N, P pools), and physical (bulk density, texture, and infiltration). All these parameters were measured at three sampling intervals (0-20, 20-40, and 60-80 cm) immediately after the plantation and a year later (n=117 per year). Also, we installed triplicated erosion plots for each cover to quantify which cover was more effective in reducing erosion and runoff. Overall, total carbon and nitrogen content increases were found after the first year (p=0.04 and p<0.001 respectively) at 20 to 40 cm.

Similarly, available nutrients such as NO₃⁻, NH₄₊ showed a significant decrease in the first two depth intervals (p<0.001). Available phosphorus also showed a net decline in the first two depth intervals (p=0.02 and p<0.001). The no-cover treatment showed significantly higher amounts of water runoff and soil erosion (p=0.04) than the other three treatments. No differences were found in runoff and erosion between hydro-mulch, coconut fiber mulch, and grass cover. Our results show that soil's chemical properties (i.e., nutrient pools and nutrient availability) are sensitive to different cover types and respond rapidly after one year of plantation with native species. On the other hand, significant changes in physical properties are not visible yet. The experiment also concludes that all tested soil covers effectively reduced runoff and erosion compared to the control. These covers should be implemented in the initial stages of the revegetation.
Fractal analysis of rain gauges’ inhomogeneous distribution and the associated hydrological impacts: the case study of Muriaé River basin
Authors: Campos Priscila Celebrini de O. , Paz Igor , Marques Maria Esther Soares , Tchiguirinskaia Ioulia , Schertzer Daniel
Published: March 2021

The urban population growth requires an improvement in the resilient behavior of these areas to extreme weather events, especially heavy rainfall. In this context, well-developed urban planning should address the problems of infrastructure, sanitation, and installation of communities, primarily related to insufficiently gauged locations. The main objectives of this study were to analyze the impacts of in-situ rain gauges’ distribution associated with the elaboration of a spatial diagnosis of the occurrence of floods in the municipality of Itaperuna, Rio de Janeiro – Brazil. The methodology consisted of the spatial analysis of rain gauges’ distribution with the help of the fractal dimension concept and investigation of flood susceptibility maps prepared by the municipality based on transitory factors (which consider precipitation in the modeling) and on permanent factors (natural flood susceptibility). Both maps were validated by the cross-tabulation method, crossing each predictive map with the recorded data of flood spots measured during a major rainfall event. The results pointed that the fractal analysis of the rain gauges’ distribution presented a scaling break behavior with a low fractal dimension at the small-scale range, mostly concerned in (semi-)urban catchments, highlighting the incapacity of the local instrumentation to capture the spatial rainfall variability. Thereafter, the cross-tabulation validation method indicated that the flood susceptibility map based on transitory factors presented an unsatisfactory probability of detection of floods when compared to the map based on permanent factors. These results allowed us to take into account the hydrological uncertainties concerning the insufficient gauge network and the impacts of the sparse distribution on the choice and elaboration of flood susceptibility maps that use rainfall data as input. Finally, we performed a spatial analysis to estimate the population and habitations that can be affected by floods using the flood susceptibility map based on permanent factors.
Discharge of the river Rhine from multi-sensor data from empirical and physical methods
Authors: Fenoglio-Marc Luciana , Zahkavova Elena , Gärtner Matthias , Zohidov Bahtiyor , Dinardo Salvatore , Duong Quang
Published: March 2021

River discharge is a key variable to quantify the water cycle and its flux.  This study focuses on the river Rhine, of width between 200 and 500 meters. River discharge is evaluated in this paper from the Sentinel-3 altimeter water level using various approches, which are the empirical rating curve method, the semi-empirical Bjerklie method and the physically-based method based on hydraulic equations.

The Sentinel-3 GPOD ESA products from the SAMOSA+ retracker perform better than the standard Copernicus products that use the OCOG and ocean retrackers. Root-mean-square errors (RMSEs) between altimetry and in-situ stations are between 0.10 m and 0.30 m at 10 of the 17 virtual tide gauge locations. The empirical rating curve method applied to the altimetric water level and in-situ discharge provides estimates of the water discharge with accuracy of 3-7% (expressed as RMSE normalized with the mean of the discharge).

The performance of the semi-empirical Bjerklie method and of the physically-based Manning algorithm to estimate the river discharge is assessed from water surface slope, elevation and top width data for different part of the river and flow conditions. Firstly, daily synthetic water surface slopes and elevations are generated from selected in-situ gauges and mean top river widths. Secondly the input to the discharge algorithm comes from the 1D-hydrodynamic model Sobek. Various choises for reach lengths and for number of observed time-series are considered. Different time sampling are used to study the effect of the repeat cycle of nadir altimeter and SWOT missions. The effect of the priori information on the accuracy of the flow water discharge is investigated.
An Earth Networks Lightning Climatology Using Thunder Hours 
Authors: Lapierre Jeff , DiGangi Elizabeth , Stock Michael
Published: March 2021

Lightning data are often used to measure the location and intensity of thunderstorms. Long term trends of thunderstorm activity can be a helpful tool for understanding our changing climate. This study presents data from the Earth Networks Global Lightning Network (ENGLN) in the form of thunder hours. A thunder hour is defined as an hour during which thunder can be heard from a given location. Thunder hours are an intuitive measure of lightning since the one-hour interval represents the life span of most airmass thunderstorms. Examining long-term lightning patterns in the context of thunder hours lends insight into thunderstorm activity without being heavily influenced by individual storm intensity, shedding light on patterns in storm activity associated with weaker thunderstorms. Thunder hour observations also reduce network performance dependencies in the dataset, making thunder hours particularly useful for studying climatology. Thunder hours have been calculated for the entire globe using 5 years of data from the ENGLN. To translate lightning flash locations to thunder hours, we converted the entire globe to a 0.05° grid, and we have slightly modified the definition of thunder-hour to an UTC hour during which lightning was located within 15 km of a given grid point. The 15 km criteria here is based on the approximate range at which thunder can be heard from a lightning flash. This study will examine global thunderstorm activity, highlighting diurnal and seasonal patterns observed across the globe.
Integrating wind energy forecasting and species population models to consider trade offs in a lower carbon future. 
Authors: Diffendorfer Jay , Lopez Anthony , Thogmartin Wayne , Mai Trieu , Straw Bethany , Udell Brad , Wiens Asthon
Published: March 2021

Renewable energy has crossed key technological hurdles related to costs and energy system stability yet impacts to wildlife may present a long-term challenge to the development and operation of renewables.  We describe a number of approaches to address interdisciplinary questions related to enhancing renewable energy development while minimizing unintended consequences to wildlife and habitat.  These approaches range from relatively simple geospatial models and Monte Carlo simulations to more sophisticated integration of spatially explicit techno-economic/physics wind energy forecasting models with bat population models. We present results from demographic models estimating impacts from future wind energy development, how including geographic constraints related to conserving natural capitol and ecosystem services may impact wind energy development and costs, and early work on temporally dynamic integration of energy and population models. We then summarize a few broader ideas on integrated modelling related to ecosystem services and energy systems. 
GeoLinkage: a GRASS-GIS plugin to integrate surface waters and groundwater in WEAP-MODFLOW models
Authors: Troncoso Felipe , Hitschfeld Nancy , Sanzana Pedro , Suárez Francisco , Muñoz José
Published: March 2021

Water resources management requires specialized computer tools that allow explicit integration of surface and groundwater fluxes, which generally have domains with different spatial discretization. On one hand, a surface hydrological domain, D1, is typically segmented in sub-basins, elevation contour bands or hydrological response units. These elements usually are represented by grids, triangles, or simple irregular polygons. In D1, the elements are connected to each other and incorporated into a drainage network that defines a surface topology, t1. On the other hand, an aquifer domain, D2, is organized in hydrogeological units, which can be represented by geometrical elements such as grids, triangulations, Voronoi or Quadratree diagrams. In D2, a regular connection is typically associated to structured meshes that defines a groundwater topology, t2. We present a new tool called GeoLinkage (v.geolinkage) that creates an ESRI-format linkage shapefile of the new surface-groundwater topology, t1-2. This python-based open-source tool has a graphical user interface (GUI) as an add-on for GRASS-GIS, which was constructed using Pygrass and Flopy libraries. It was developed to be used in WEAP-MODFLOV models, but it can also be used with other water resources management models. GeoLinkage allows processing models with reasonable computation times, which facilitates scenario analysis. It calculates the locations of the surface element geometries (nodes and arcs) using the GRASS platform and connects them to each element of a structured mesh in MODFLOW models. GeoLinkage was applied to obtain groundwater levels and coverage of water demand in Azapa Valley, a hyper-arid zone in the desert of Chile, where a grid of 70.305 cells and six fields with detailed geometry were processed in only 12 min.
Investigating Fast- and Slow-settling Phosphorus Fractions in Lakes using Steady-state Modeling
Authors: Khorasani Hamed , Zhu Zhenduo
Published: March 2021

Phosphorus (P) is the key and limiting nutrient in the eutrophication of freshwater resources. Modeling P retention in lakes using steady-state mass balance models (i.e. Vollenweider-type models) provides insights into the lake P management and a simple method for large-scale assessments of P in lakes. One of the basic problems in the mass balance modeling of P in lakes is the removal of P from the lake water column by settling. A fraction of the incoming P into the lake from the watershed is associated with fast-settling particles (e.g. sediment particles) that result in the removal of that fraction of P quickly at the lake entrance. However, existing models considering a constant fraction of fast-settling TP for all lakes are shown to result in overestimation of the retention of P in lakes with short hydraulic residence time. In this study, we combine a hypothesis of the fast- and slow-settling P fractions into the steady-state mass balance models of P retention in lakes. We use a large database of lakes to calibrate the model and evaluate the hypothesis. The results of this work can be used for the improvement of the prediction power of P retention models in lakes and help to better understand the processes of P cycling in lakes.
Warming of the Indian Ocean weakens the Atlantic Niño - El Niño Southern Oscillation connection 
Authors: Dhame Shreya , Taschetto Andréa , Santoso Agus , Liguori Giovanni , Meissner Katrin
Published: March 2021

The tropical Indian Ocean has warmed by 1 degree Celsius since the mid-twentieth century. This warming is likely to continue as the atmospheric carbon dioxide levels keep rising. Here, we discuss how the warming trend could influence the El Niño Southern Oscillation (ENSO) via interaction with the Pacific and the Atlantic Ocean mean state and variability. The warming trend leads to the strengthening of easterlies in the western equatorial Pacific, subsequent downwelling and increase of the mixed later depth in the west, and an increase in the subsurface temperature gradient across the equatorial Pacific. In the eastern equatorial Pacific, the response of upwelling ocean currents to surface wind stress decreases, resulting in a weakening of ENSO amplitude. The Indian Ocean warming influences ENSO via the Atlantic Ocean as well. There, it is associated with the strengthening of equatorial easterly winds, and anomalous warming in the west and upwelling induced cooling in the east, especially in austral winter, during the peak of the Atlantic Niño. Consequently, this results in a decrease of the amplitude of Atlantic Niño events and weakening of the Atlantic Niño-ENSO teleconnection, thereby hindering the transition of El Niño events to La Niña events. Thus, the Indian Ocean warming trend is found to modulate tropical Pacific and Atlantic mean state and variability, with implications for ENSO predictability under a warming climate.
A triumvirate of peat landslides: A transdisciplinary approach for a not-so-natural- hazard in Ireland.
Authors: Bourke Mary , Halpin Rob , Farrell Catherine , Long Michael , Connolly John
Published: March 2021

Landslides are traditionally viewed through geomorphological, ecological, geophysical, and hydrological lenses, often taking a multi-disciplinary approach. More recently, there have been calls for a different approach- one that acknowledges the increasing importance of socio-environmental stresses that can also affect slope instability. For Ireland, environmental stresses in peatlands are connected to the utilisation of land as a resource that is linked to commercia development, and indeed, towards supporting financial investment in rural areas by various governments, e.g., peat mining, agricultural grazing, afforestation, and wind farm construction.

Weather conditions in Ireland during the 2020 summer and autumn were unusually dry and warm, followed by intense summer storms and longer duration rainfalls. These antecedent conditions are known to increase susceptibility to landslides, especially in organic (peat) soils. Three slope failures in peat occurred in 2020: one in June in Co. Leitrim and two in November in Co. Kerry and Co. Donegal. Landslide susceptibility ratings for all sites were in the lower range.

We adopt a transdisciplinary approach in a study of these three peat landslides and bring together the disciplinary expertise of engineering, geomorphology, hydrology, ecology and land-use.

These three sites provide an opportunity to better constrain the physical properties of peat for comparison with other ecologically similar sites, an area of research that is still developing. In addition, we focus on understanding the altered drainage (hydrology) and the recovery (through natural revegetation and succession) of these sites.

We call for the assessment of the hazard to more fully include the feedback that exists through the connectivity of landscape systems (e.g., colluvial, fluvial and lacustrine/marine). In addition, we recommend that peat landslides be evaluated over extended timescales, beyond the immediate impacts to capture longer-term (secondary) effects on water and ecology in general as well as human enterprise.  An inclusion of an analysis of the historical and modern land-use and management of peatland areas in the uplands of Ireland brings the study towards a fuller appreciation of the factors that increase peatland hazard.

Our transdisciplinary approach ensures that the ‘real’ hazard types and levels are identified, particularly in the context of an increasing population expansion, changes in land use and trends in the climate scenario for Ireland.
The Ionospheric Source of the Plasma Sheet During Storm Main Phase
Authors: Kistler Lynn M. , Mouikis Christopher G. , Asamura Kazushi , Kasahara Satoshi , Miyoshi Yoshizumi , Keika Kunihiro , Petrinic Steven M. , Hori Tomoaki , Yokota Shoichiro , Shinohara Iku
Published: March 2021

The ionospheric and solar wind contributions to the magnetosphere can be distinguished by their composition.  While both sources contain significant H+, the heavy ion species from the ionospheric source are generally singly ionized, while the solar wind consists of highly ionized ions. Both the solar wind and the ionosphere contribute to the plasma sheet.  It has been shown that with both enhanced geomagnetic activity and enhanced solar EUV, the ionospheric contribution, and particularly the ionospheric heavy ions contribution increases.  However, the details of this transition from a solar wind dominated to more ionospheric dominated plasma sheet are not well understood.  An initial study using AMPTE/CHEM data, a data set that includes the full charge state distributions of the major species, shows that the transition can occur quite sharply during storms, with the ionospheric contribution becoming dominant during the storm main phase.  However, during the AMPTE time-period, there were no continuous measurements of the upstream solar wind, and so both the simultaneous solar wind composition and the driving solar wind and IMF parameters were not known.  The HPCA instrument on MMS and both the LEPi and MEPi instruments on Arase are able to measure He++.   With these data sets, the He++/H+ ratio can be compared to the simultaneous He++/H+ ratios in the solar wind to more definitively identify the solar wind contribution to the plasma sheet.  This allows the ionospheric contribution to the H+ population to be determined, so that the full ionospheric population is known. We find that when the IMF turns southward during the storm main phase, the dominant source of the hot plasma sheet becomes ionospheric.  This composition change explains why the storm time ring current also has a high ionospheric contribution.
Impacts of poldering: elevation change, sediment dynamics, and subsidence in the natural and human-altered Ganges Brahmaputra tidal deltaplain
Authors: Wilson Carol , Akter Sharmin , Rana Masud , Steckler Michael , Oryan Bar
Published: March 2021

In the Ganges-Brahmaputra Delta (GBD) and other tide-dominated low-lying regions, periodic tidal and cyclonic storm surge flooding of the land surface promotes sediment accretion and surface elevation gain which offsets elevation losses from eustatic sea level rise and subsidence. However, over the past several decades, anthropogenic modification of the GBD tidal deltaplain through embankment construction has precluded sediment delivery to densely populated embanked islands, locally-termed polders, resulting in landscapes 1-1.5 m lower than adjacent natural mangrove platforms. Recent discussion on GBD sustainability includes whether land surfaces (natural or anthropogenic) are keeping pace with local sea-level rise rates, and the quantification of continued elevation change, vertical accretion, and land subsidence. To provide local-scale, longitudinal trends of landscape dynamics, an array of Rod Surface Elevation Tables (RSETs) and sediment marker horizons was deployed in natural and embanked settings near Polder #32 and monitored seasonally over the past 6 years (expanded throughout the SW delta in 2019). These data are compared to existing and new co-located continuous GPS measurements (also expanded 2019). Near Polder #32, elevation gain is taking place in both natural and embanked regions (1-3 cm/yr), though it appears to be slightly greater (30%) within the poldered areas. This may be due to increased accommodation space and/or embankment sloughing. There also is a distinct seasonal pattern in both regions, with greater elevation change documented after the wet monsoon season (May-Sept), and either less elevation gain, or even elevation loss after the winter dry season (Jan-May). Elevation gain is a direct result of exceptionally large sediment vertical accretion (2-3 cm/yr), as measured from marker horizons and sediment tiles, and rates appear to be keeping pace with local effective sea-level rise documented by Pethick and Orford (2013). Seasonal shallow subsidence (0.8-1.1 cm/yr) is also observed, exacerbated in poldered regions during the dry season. These measurements of shallow subsidence are 30-50% greater than deeper subsidence measured with GPS (0.3-0.7 cm/yr) but consistent with resurveys of geodetic monuments (see Steckler et al. abstract). Preliminary results delta-wide show shallow subsidence can be as much as 3 cm over the course of one year. These data provide critical information to local stakeholders about the natural versus human-altered delta dynamics, and have cross-disciplinary implications for ecological productivity, social well-being, and flood risk mitigation.
How well do standard laboratory methods represent the field water retention curve of volcanic ash soils (Andosols)?
Authors: Mosquera Giovanny , Marín Franklin , Feyen Jan , Célleri Rolando , Breur Lutz , Windhorst David , Crespo Patricio
Published: March 2021

Accurate determination of the water retention curve (WRC) of a soil is essential for the understanding and modelling of the subsurface hydrological, ecological, and biogeochemical processes. Volcanic ash soils with andic properties (Andosols) are recognized as important providers of ecological and hydrological services in mountainous regions worldwide due to their outstanding water holding capacity. Previous comparative analyses of in situ (field) and standard laboratory (hydrostatic equilibrium based) methods for the determination of the WRC of Andosols showed contrasting results. Based on an extensive analysis of laboratory, experimental, and field measured WRCs of Andosols in combination with data extracted from the published literature we show that standard laboratory methods using small soil sample volumes (≤300 cm3) mimic the WRC of these soils only partially. The results obtained by the latter resemble only a small portion of the wet range of the Andosols’ WRC (from saturation up to -5 kPa, or pF 1.7), but overestimate substantially their water content for higher matric potentials. The disagreement limits our capacity to infer correctly subsurface hydrological behavior, as illustrated through the analysis of long-term soil moisture and matric potential data from an experimental site in the tropical Andes. These findings imply that results reported in past research should be used with caution and that future research should focus on determining laboratory methods that allow obtaining a correct characterization of the WRC of Andosols.
Eastern equatorial Pacific warming delayed by aerosols and thermostat response to CO2
Authors: Heede Ulla K. , Fedorov Alexey V.
Published: March 2021

Understanding the tropical Pacific response to global warming remains a challenging problem due to discrepancies between models and observations, as well as a large intermodel spread in future projections. Here, we assess the recent and future evolution of the equatorial Pacific east-west temperature gradient, and the Walker circulation within the CMIP6 dataset. Using 40 models, we compare simulated tropical climate change across a wide range of experiments with varying CO2 and aerosol forcing. In abrupt CO2-increase scenarios, many models generate an initial strengthening of the east-west gradient resembling an ocean thermostat (OT), characterized by lack of warming in the central Pacific, followed by a small weakening; other models generate an immediate weakening that becomes progressively larger establishing a pronounced eastern equatorial Pacific (EP) warming pattern. The initial response in these CO2-only experiments is a very good predictor for the future EP pattern simulated in future warming scenarios, but not in historical simulations showing no multi-model trend. The likely explanation is that recent CO2-driven changes in the tropical Pacific, which are relatively small compared to future projections, are masked by aerosol effects. In future warming scenarios, however, the EP warming pattern emerges within 20-40 years as greenhouse gases overcome aerosol forcing. These findings highlight the need to understand the largely overlooked, but possibly significant role of aerosols in delaying sea surface warming in the tropical Pacific, and the implications for predicting future climate change across the tropics.
Impact of Increasing Horizontal and Vertical Resolution during the HWRF Hybrid EnVar Data Assimilation on the Analysis and Prediction of Hurricane Patricia (2015)
Authors: Feng Jie
Published: March 2021

Although numerous studies have demonstrated that increasing model spatial resolution in free forecasts can potentially improve tropical cyclone (TC) intensity forecasts, studies on the impact of model resolution during data assimilation (DA) on TC prediction are lacking.  In this study, using the ensemble-variational DA system for Hurricane Weather Research and Forecasting (HWRF) model, we investigated the individual impact of increasing the model resolution of first guess (FG) and background ensemble (BE) forecasts during DA on initial analyses and subsequent forecasts of Hurricane Patricia (2015).  The impacts were compared between horizontal and vertical resolutions and also between the tropical storm (TS) and hurricane assimilation during Patricia.

The results show that increasing the horizontal or vertical resolution in FG has a larger impact than increasing the resolution in BE on improving the analyzed TC intensity and structure for the hurricane stage. The result is reversed for the TS stage.  These results are attributed to the effectiveness of increasing the FG resolution in intensifying the background vortex for the hurricane stage relative to the TS stage.  Increasing the BE resolution contributes to improving the analyzed intensity through the better-resolved background correlation structure for both the hurricane and TS stages.  Increasing horizontal resolution has an overall larger effect than increasing vertical resolution in improving the analysis at the hurricane stage and their effects are close for the analysis at the TS stage. Additionally, the more accurately analyzed primary, secondary circulation, and warm core structures via the increased resolution in DA lead to improved TC intensity forecasts.
The Cenomanian–Turonian Oceanic Anoxic Event 2 and the Late Turonian-Coniacian Event in the Mexican Interior Basin
Authors: Nunez Fernando , Colin-Rodríguez Azucena , Adatte Thierry , Omaña-Pulido Lourdes , Alfonso Pura , Pi Teresa , Correa-Metrio Alexander , Barragán Ricardo , Martínez-Yáñez Mario , Enciso Cárdenas Juan Josué
Published: March 2021

In the modern ocean, deoxygenation is a major consequence of climate change induced by eutrophication and expansion of oxygen minimum zones.  To better understand the exact mechanisms that promote the development of anoxia requires observations not available at human time scale, and therefore demand the study of intervals of rapid warming in the geologic past. During the Cretaceous Period, massive submarine volcanism during the construction of Large Igneous Provinces gave rise to the development of several episodes of widespread oxygen-depleted waters and enhance organic carbon deposition, including the  Cenomanian-Turonian Oceanic Anoxic Event 2 (OAE 2) and the  Late Turonian–Coniacian Event (LTCE). In this study, we reconstruct climate and oceanographic conditions in the Mexican Interior Basin during these events, a key area that connected the Western Interior Seaway to the equatorial Atlantic Tethyan water mass. To accomplish this, we applied an integrated multi-proxy approach that includes sedimentological, microfacies, mineralogical and geochemical data from a upper Cenomanian–lower Coniacian section.

Organic-rich sediments were accumulated during the initial stage of OAE 2 and the middle stage of LTCE (Hitchwood Event), under increasingly warm and humid conditions, as evidenced by high chemical index of alteration (CIA) values. High detrital index (DI) values coupled with high phosphorus mass-accumulation rates suggest that this scenario increased detrital and nutrients fluxes. Eutrophic-anoxic/dysoxic marine conditions are corroborated by the highest TOC values coinciding with significant enrichments in redox- and productivity-sensitive trace elements. Moreover, they are supported by the abundant presence of radiolarians and filaments in the OAE 2 interval, and the occurrence of opportunistic foraminifera in the LTCE interval. Oxygen-depleted bottom waters are also indicated by Mo–U systematics and a small-sized population of pyrite. The onset of the Mexican Orogen tectonic uplift together with upwelling intensified the transference of nutrients and enhanced organic matter burial during the initial stage of OAE 2. In the mid-OAE 2 δ13C trough interval equivalent to the Plenus Cold Event, bioturbated sediments with low TOC values accumulated during a short episode of cold climate conditions reflecting the southward flow of boreal water throughout the Mexican Interior Basin. The minimum δ34Spy value occurring within the OAE 2 interval in the Mexican Interior Basin is lower than elsewhere due to a local increase in sulfate concentrations.
Initiative to establish the International Geodiversity Day
Authors: Zwoliński Zbigniew , Brilha Jose , Gray Murray , Matthews Jack
Published: March 2021

On May 22, 2020, when International Biodiversity Day was celebrated, Murray Gray and Zbigniew Zwoliński independently wrote an email to José Brilha with a proposal to make efforts to establish the International Geodiversity Day (IGD). This was on the eve of the Oxford Geoheritage Virtual Conference (OxGVC) launch. Therefore, at the end of the conference, a declaration of establishing the IGD was prepared, which was supported by over 600 participants from over 60 countries. Virtual PICO presents further and ongoing scientific, organizational and diplomatic efforts to proclaim the IGD: starting from the Oxford Declaration, through letters of support from 108 individuals and international and national professional earth science nature conservation organizations and the International Union of Geological Sciences to Natural Sciences Sector – Division for Earth and Ecological Sciences UNESCO and Executive Board of UNESCO.

The proclamation of an International Geodiversity Day would provide an annual reminder of the essential role of geodiversity for human well-being. It provides the foundations and habitats for all living things. It is the source of materials that build our towns and cities; it provides our energy resources, including renewable energy and the materials mined to manufacture wind turbines and solar panels; it allows us to bury our waste, provides us with freshwater and attenuates our pollution; it helps us to understand and predict natural hazards, it inspires our artists and provides us with incredible landscapes from mountains to coasts. Geodiversity gives us evidence of past climate and landscape changes and their causes, and therefore helps us to understand and plan for the impacts of future environmental changes.
Modelling the Hydrologic Regime of Arid Inland Wetlands: Non-linear Relationship Between Root-uptakes of Water and Underground Water Table
Authors: Li Lin , Liu Hu , Yu Yang , Zhao Wenzhi
Published: March 2021

Abstract: Wetlands remaining in the arid inland river landscapes of northwestern China suffer degradation and their resilience and ability to continue functioning under hydrologic and land use changes resulting from climate change may be significantly inhibited. Information on the desert-oasis wetlands, however, is sparse and knowledge of how ecological functioning and resilience may change under climate change and water-resource management is still lacking. Research in oasis wetland areas of the Northwestern China identified linkages between subsurface flow, plant transpiration, and water levels. In this study, we present an ecohydrological analysis of the energy and water balance in the wetland ecosystem. A process-based stochastic soil moisture model developed for groundwater-dependent ecosystems was employed to modelling the interactions between rainfall, water table fluctuations, soil moisture dynamics, and vegetation, and to investigate the ecohydrology of arid inland wetlands system. Field measured groundwater levels, vertical soil moisture profiles, soil water potentials, and root biomass allocation and transpiration of pioneer species in the wetlands were used to calibrate and validate the stochastic model. The parameterized model was then running to simulate the probability distributions of soil moisture and root water uptake, and quantitative descript the vegetation–water table–soil moisture interplay in the hypothesized scenarios of future. Our analysis suggested the increasing rates of water extraction and regulation of hydrologic processes, coupled with destruction of natural vegetation, and climate change, are jeopardizing the future persistence of wetlands and the ecological and socio-economic functions they support. To understand how climate change will impact on the ecohydrological functioning of wetlands, both hydrological and land use changes need to be considered in future works.

Keywords: Wetland ecosystem, groundwater, soil moisture dynamics, water balances, Heihe River Basin
Effects of anthropogenic degradation of an Andean temperate forest on the soil nutrients and on the diversity and function of the soil microbial community
Authors: Atenas Alejandro , Aburto Felipe , Hasbun Rodrigo , Merino Carolina
Published: March 2021

Soil microorganisms are an essential component of forest ecosystems being directly involved in the decomposition of organic matter and the mineralization of nutrients. Anthropogenic disturbances such as logging and livestock modify the structure and composition of forests and also the structure and diversity of soil microbial communities changing critical biogeochemical processes in the soil. In this research we evaluated the effect of anthropic disturbance on the soil in a degradation gradient of Andean temperate forest. This gradient comprises mature forest stands dominated by Nothofagus dombeyii, secondary forests dominated by Nothofagus alpina with medium degradation, a highly degraded forests dominated by Nothofagus obliqua and a highly degraded grassland. We evaluate the reservoir of the main soil nutrients (TC, TN, NO3-, NH4+) and the structure, diversity and functions of the soil microbial community (bacteria and fungi) via NGS-Illumina sequencing and metagenomic análisis with DADA2 pipeline in R-project. The results show a higher amount of TC, TN, NO3- and C:N ratio in the most degraded condition (degraded grassland). There are no significant differences in the amount of TC, TN and NH4+ along the forest degradation gradient. This reflects a C:N:P stoichiometry that tends to decrease as forest degradation increases. The soil bacteria community was mainly dominated by Phyla Proteobacteria (45.35%), Acidobacteria (20.73%), Actinobacteria (12.59%) and Bacteroidetes (7.32%). At genus level there are significant differences, Bradyrhizobium has a higher relative abundance in the condition of mature forest which tends to decrease along the gradient of degradation forest. The soil fungi community was dominated by the Phyla Ascomycota (42.11%), Mortierellomycota (28.74%), Basidiomycota (24.61%) and Mucoromycota (2.06%). At genus level the condition of degraded grassland has significantly lower relative abundance of the genera Mortierella and Cortinarius. The degraded grassland soil microbial community is significantly less diverse in terms of bacteria (D' = 0.47±0.04) however it is significantly more diverse in terms of fungi (H' = 5.11±0.33).
Alteration in tides and flood dynamics caused by channel deepening:  case study of the Saint Johns River, Florida
Authors: Talke Stefan , Jay David , Familkhalili Ramin
Published: March 2021

In this contribution, we show that channel deepening can amplifiy tide and storm surge--while simultaneously decreasing the river slope during both normal conditions and during floods.  We investigate the Saint Johns River Estuary, Florida, an example of a hyposynchronous, strongly frictional estuary with a landward decay in tidal amplitudes. Records since the 1890s and numerical modeling show that tidal range doubled in Jacksonville, Florida (40 km from coast), while tidal discharge approximately doubled everywhere. Overall, an increase in channel depth from 5 to 10m drove the observed changes, with width and length changes comparatively minor factors. Tidal amplitude evolved in a spatially variable way--negligible at the coast and inland, maximal 20-30km from the ocean.  The change in the M2 constituent is approximated by the equation x * exp(mu*x), where x is the distance from the ocean and mu is a damping coefficient that depends on depth, drag coefficient, and other system properties.  The observed tidal evolution is similar to storm surge:  Numerical modeling of hurricane Irma (Sept. 2017) under 1898 and 2017 bathymetric conditions confirms that both tidal and storm surge amplitudes have increased over time, with a maximum change about 20-25km from the inlet. Nonetheless, hurricane Irma produced overall high water levels in the historical bathymetric configuration. The reason is that the mean water level slope required to move water out of the modern estuary has decreased. An analytical model confirms that reduced slope is caused primarily by channel deepening.  However, greater tides and storm surge imply an increased vulnerability to a worst-case scenario hurricane. 
Combining a data-driven approach with seasonal forecasts data to predicting reservoir water volume in the Mediterranean area.
Authors: Francipane Antonio , Arnone Elisa , Noto Leonardo Valerio
Published: March 2021

Artificial reservoirs are one of the main water supply resources in the Mediterranean areas; their management can be strongly affected by the problems of drought and water scarcity. The reservoir water level is the result of the hydrological processes occurring in the upstream catchment, which, in turn, depend on meteorological variables, such as rainfall and temperature. It follows that a reliable forecast model of the meteorological forcing, along with a reliable water balance model, could enhance the correct management of a reservoir. With regard to the rainfall/temperature forecast model, the use of forecast climate data in the mid-term may provide further support for the future water level estimation of reservoirs.

From the perspective of the water balance model, instead, among the approaches used to predict the water levels for the next future, those based on data-driven methods have been demonstrated to be particularly capable of correctly reproducing the correlation between a dependent variable (e.g., water level, volume) and some covariates (e.g., temperature, precipitation).

This study describes the preliminary results of a novel application that exploits the Seasonal Forecast (SF) data, produced at the European Centre for Medium-Range Weather Forecasting (ECMWF), within a data-driven model aimed to predict the reservoir water volume at mid-term scale, up to 6 months ahead in four reservoirs of the Sicily (Italy) here considered as a case study. For each case, a NARX (Nonlinear AutoRegressive network with eXogenous inputs) neural network is calibrated to reproduce the monthly stored water volume starting from the monthly precipitation and mean monthly air temperature variables.

Preliminary results showed that the NARXs have the capability to reproduce the water levels in the investigated period (January 2017 - April 2020), including the variations during more or less dry periods. All this despite the SF data have not been previously treated with downscaling and/or bias correction techniques.
Effects of SO2 emissions in Alberta, Canada on lodgepole pine climate-growth relationships
Authors: Earl Devon , Norman Ann-Lise , Reid Mary
Published: March 2021

The growth response of trees to climate can be altered by other environmental changes that a tree may face including pollution or fertilization. In this study, the effect of spatial and temporal patterns sulfur dioxide (SO2) emissions on climate-growth relationships of lodgepole pine (Pinus contorta) in two areas of Alberta, Canada was assessed. Twenty tree cores were collected in each of four stands per study area: two near a source of SO2 emissions (sour gas processing facility) and two far from the source of emissions. To select important climate variables, the average standardized tree ring width of all trees in each area were first compared to monthly average temperature and total precipitation variables. For each important climate variable, response function analysis was conducted between standardized tree ring widths and climate in each of three SO2 exposure time periods: a period pre-dating any emissions, a period of high emissions, and a more recent period of reduced emissions. Linear mixed models were used to compare response coefficients of tree ring widths to climate between exposure space (near or far from the source of emissions) and exposure time (no emissions, high emissions, reduced emissions) and the interaction between them. The absolute values of predicted ring widths in each exposure space and exposure time in each area were used as a response variable in a linear mixed effects model to assess the effects of SO2 exposure on the magnitude of tree growth response to climate. SO2 exposure time was a significant term in all climate-growth relationship models. Exposure space was significant in 13 out of 20 models, and the interaction between exposure time and exposure space was significant in 14 out of 20 models. The effects of exposure time and exposure space on climate-growth relationships were not consistent between climate variables. Overall, tree growth responded most strongly to climate in the high exposure time period. The increase in magnitude of climate-growth relationships in the high SO2 exposure time period may indicate that trees stressed by sulfur deposition are not able to buffer the effects of climate, and are more susceptible to extreme weather conditions such as drought. However, the response to climate during the high emission period was greater far from the source of emissions than near the source of emissions; This could be because the historical addition of lime to stands near the sour gas processing facilities resulted in less sulfur stress. SO2 emissions in Alberta may alter climate-growth relationships of lodgepole pine.  
Can snow persistence explain the spatial-temporal variabilities in streamflow hydrograph flashiness across snow-dominated regions?
Authors: Le Edward , Ameli Ali , Janssen Joseph , Hammond John , Krugger Kristo Elijah
Published: March 2021

Recent research showed that, snow persistence, defined here as the fraction of time that snow is present on the ground, can play an important role in explaining spatial variability of average annual streamflow in moderately snowmelt-dominated regions. Here, we extend this work and explore the following questions: 1) whether globally available snow persistence data is useful for estimating a suite of streamflow signatures explaining the shape, flashiness and components of streamflow hydrograph, and 2) whether snow persistence could be useful for reconstructing streamflow patterns in ungauged watersheds, both spatially and temporally. We explore these questions across a spectrum of climatic dryness, snowiness, and geological settings. The motivations for the study are the need to understand how loss of snow may affect the components of streamflow in different climatic and geological settings, as well as the need for simple methods to predict components of streamflow in snow-dominated ungauged basins.
Investigating of River-Aquifer Interactions using Sub-Surface Hydrological Model and Remote Sensing Inputs in an agriculturally Dominated Kosi River Basin, India.
Authors: Laveti Naga Venkata Satish , Kartha Suresh A. , Dutta Subashisa
Published: March 2021

River-Aquifer Interaction is a natural and complex phenomenon for understanding its physical dynamic processes. These interactions highly vary with time and space and are to be investigated at river reach scale. The present study aims to understand and quantify the spatio-temporal variations of river-aquifer interaction process in Kosi river basin, India. This basin is majorly dominated with agricultural lands and irrigation requirement of the crops are mostly met by groundwater. In order to quantify the river-aquifer exchange flux at reach scale, a physically based sub-surface hydrological model has been carried for the study area. For this purpose, high resolution remotely sensed evapotranspiration data and groundwater recharge (estimated using soil water budget method method) along with other aquifer parameters were utilized for simulating the monthly groundwater levels as well as exchange flux between river and aquifer. The model results showed that simulated groundwater levels were well calibrated and validated with measured groundwater levels. Further, this calibrated groundwater flow model has been used to quantify the river-aquifer exchange flux. Based on the obtained exchange flux values, three different interaction zones were identified from upstream (Kosi barrage) to downstream (confluence point with Ganga river) in the study reach. It is observed that the river mostly loses water to the aquifer (as influent) in Zone I (80km from upstream) and the river mostly gains water from the aquifer (as effluent) in Zone III (40 km above downstream to confluence point). Whereas, the river has a combination of both losing and gaining natures in Zone II (between Zone I and III). From this study, it can be concluded that use of satellite remote sensing inputs (groundwater recharge and evapotranspiration) in the sub-surface hydrological model, facilitated to improve the assessment and understanding river-aquifer interaction process in an alluvial River basin.