bluuebunny/crossref_metadata_2025 huggingface dataset:
Responses of Fagus sylvatica growing in Southern Italy to climate change: insight from sap flow continuous monitoring
Authors: Kabala Jerzy Piotr , Niccoli Francesco , Battipaglia Giovanna
Published: February 2023

The ongoing climate change, with altered precipitation regimes and altered evaporative demand due to the increase in temperature are affecting hydrological conditions in most forest sites in Europe. This change has strong consequences on the distribution, composition and ecological functioning of forest species . Fagus sylvatica is one of the most important species in Europe, spanning from southern Scandinavia to the Mediterranean region. Species distribution models forecast a reduction of the area of distribution of F. sylvatica in Italy under the climate change scenarios. The hydraulic behaviour and transpiration responses of the beech to climate conditions have been studied in central Europe. However, this has been scarcely addressed in the southernmost part of its distribution area, where this knowledge might be critical in understanding the physiological responses of this species to climate change, and then its capability to persist in the area.This study aims to understand the responses of the transpiration of a Fagus sylvatica forest to meteorological variables in the southern Apennines (Matese Regional Park, Italy). The forest stand has been continuously monitored for 2 years with the TreeTalker devices, that record sap flux data at an hourly scale, along with several microenvironmental parameters. The monitoring period encompasses the droughty 2022 year, with high temperatures and precipitations well below the average.The forest stand studied varies its sap flux in response to the environmental conditions, by reducing its transpiration in late summer, when VPD is high, but water availability is low. This conservative hydraulic behaviour seems to protect the trees from immediate damage due to drought periods, as no tree mortality has been observed. These results suggest that even if in the past Fagus sylvatica has been considered an anisohydric species, the southern ecotypes show a more isohydric behaviour than expected. The prosecution of this monitoring might provide further information about long-term trends in the ecophysiology of this forest.
Intra-decadal variability of the Indian Ocean shallow meridional overturning circulation during boreal winter
Authors: Pai Rahul , Parekh Anant , Chowdary Jasti S , Chellappan Gnanaseelan
Published: February 2023

The variability of Indian Ocean shallow meridional overturning circulation (SMOC) is studied using the century-long ocean reanalysis simple ocean data assimilation (SODA) data. Though SMOC exhibits stronger southward transport during boreal summer, it displays stronger variability during boreal winter. The spectrum analysis of the winter SMOC index reveals the presence of the highest amplitude between 5 to 7 years at 95% confidence level, suggesting the dominance of intra-decadal SMOC variability. The robustness of intra-decadal SMOC variability is also confirmed in different ocean reanalysis data sets. Composite analysis of filtered upper Ocean Heat Content, sea level, thermocline depth, and Sea Surface Temperature anomalies for strong (weak) SMOC years show negative (positive) anomalies over north and East of Madagascar. Correlation analysis, of filtered SMOC index and sea level pressure (zonal winds) over the Indian Ocean, found a significant negative (positive) correlation coefficient north of 40 °S (around 10 °S) and a significantly positive (negative) correlation coefficient over the 45 °S to 70 °S (20 °S to 50 °S and north of 5 °S). This meridional pattern of the correlation coefficient for sea level pressure, manifesting the out-of-phase relationship between sub-tropics and high latitude mean sea level pressure, resembles Southern Annular Mode (SAM). We conclude that the intra-decadal variability of mean sea level pressure leads to zonal wind variation around 10 °S modulating SMOC, which in turn affects the upper ocean thermal properties in the east and north of Madagascar. This study for the first time brought out coherent intra-decadal evolution of SAM and SMOC during boreal winter.
Potentials and challenges of using Explainable AI for understanding atmospheric circulation
Authors: Scher Sebastian , Trügler Andreas , Abermann Jakob
Published: February 2023

Machine Learning (ML) and AI techniques, especially methods based on Deep Learning, have long been considered as black boxes that might be good at predicting, but not explaining predictions. This has changed recently, with more techniques becoming available that explain predictions by ML models – known as Explainable AI (XAI). These have seen adaptation also in climate science, because they could have the potential to help us in understanding the physics behind phenomena in geoscience. It is, however, unclear, how large that potential really is, and how these methods can be incorporated into the scientific process. In our study, we use the exemplary research question of which aspects of the large-scale atmospheric circulation affect specific local conditions. We compare the different answers to this question obtained with a range of different methods, from the traditional approach of targeted data analysis based on physical knowledge (such as using dimensionality reduction based on physical reasoning) to purely data-driven and physics-unaware methods using Deep Learning with XAI techniques. Based on these insights, we discuss the usefulness and potential pitfalls of XAI for understanding and explaining phenomena in geosciences. 
Hydraulic-trait diversity increases tropical forest resistance to water deficits.
Authors: Langan Liam , Scheiter Simon , Hickler Thomas , Higgins Steven
Published: February 2023

Amazon rainforests host a unique biodiversity, store vast amounts of carbon, and are an essential component of the Earth System. Future water balance changes put the Amazon's carbon storage potential at risk. Evidence from grasslands indicates that diversity can mediate responses to drought; however, it remains unclear how tropical forests will respond. We show that functional diversity increases forest resistance to biomass loss during sudden catastrophic drought and chronic climate change-associated precipitation reductions by up to 25%. Using a model capable of simulating drought responses and functional diversity, we found that distinct strategies emerged along hydraulic and carbon allocation axes of trait variation. Climate change and elevated CO2 caused the re-assembly of communities towards increased water-triggered phenological strategy dominance, whereas climate change alone negatively influenced biomass stored across all strategies. By removing water-triggered evergreen and deciduous strategies, we show that more biomass is lost in the absence of these strategies and thus clearly illustrate that higher diversity buffers the impacts of water balance changes. Our results demonstrate that a predictive understanding of trait diversity and plant hydraulic traits is essential to understand the complexity of diversity-biomass relations under future climate. 
Groundwater Residence Time in Iceland Depicted by Stable Water- and Carbon Isotopes
Authors: Sveinbjornsdottir Arny , Stefánsson Andri , Arnórsson Stefán
Published: February 2023

Iceland is young (the oldest rocks ca 16M years) and characterized by active and widespread volcanism, defined along a Neovolcanic rift zone.  More than 90% of the Icelandic bedrock is of basaltic origin. The permeability of the Tertiary lava pile is 1-4*10-14 m2 but for younger geological formations especially within geothermal areas the permeability is several orders of magnitude higher due to active fissures and faults. The deeper crust has however a very low permeability as pores and fissures are filled with secondary minerals. Due to the high permeability in the upper crust groundwater is often mixed with water components originating from different conditions, of different age and in some cases also affected by water-rock interaction.   Thus groundwater dating is complex and to succeed in estimating groundwater residence time it is of vital importance that interdisciplinary methods are applied to understand the geochemistry, geology and hydrology of a specific groundwater system. In this presentation an overview of using stable water- and carbon isotopes to estimate groundwater residence time is given. It is demonstrated how stable water isotopes including the second order parameter; deuterium excess, can be used to estimate relative ages. Also how radiocarbon age estimations have successfully been used when comprehensive corrections for “dead carbon” from the bedrock and CO2 gas from the deep crust or mantle are applied together with δ13C to correct for modern carbon of organic origin.
Direct evidence for elevated UV-B radiation and ozone layer disruption during the end-Permian mass extinction
Authors: Jardine Phillip , Peng Huiping , Marshall John , Lomax Barry , Bomfleur Benjamin , Kent Matthew , Fraser Wesley , Lui Feng
Published: February 2023

The end-Permian mass extinction (EPME) is the largest extinction event of the Phanerozoic, but the specific causal pathways, especially in the terrestrial realm, are unresolved. Malformed pollen and spores recovered from the EPME interval have been taken as indicators of extreme environmental stress in terrestrial ecosystems. However, whether they relate to volcanism-driven ozone-layer deterioration and enhanced ultraviolet-B (UV-B) flux, or volcanogenic toxic pollutants including mercury and acid rain, or some combination of the two, remains unclear. Here, we take advantage of a novel palynological proxy, which utilises the ability of land plants to adjust the concentration of protective UV-B-absorbing compounds (UACs) in the outer wall of their reproductive propagules in response to changes in ambient UV-B flux. We analysed UAC abundances in ca. 800 pollen grains from an independently-dated Permian-Triassic boundary section in southern Tibet, in order to infer changes in UV-B-radiation flux at the Earth’s surface during the EPME. Our data reveal an excursion in UACs that coincides with a spike in mercury concentration and a negative carbon-isotope excursion in the latest Permian deposits, suggesting a close temporal link between large-scale volcanic eruptions, global carbon- and mercury-cycle perturbations, and ozone-layer disruption. Because enhanced UV-B radiation can exacerbate the environmental deterioration induced by massive magmatism, ozone depletion is considered a compelling ecological driver for the terrestrial mass extinction.
A forward stratigraphic model of the Cenozoic multi-source-to-sink system in the Barents Sea, Norwegian Arctic
Authors: Lasabuda Amando P. E. , Chiarella Domenico , Sømme Tor , Grundvåg Sten-Andreas , Rydningen Tom Arne , Patton Henry , Laberg Jan Sverre , Hanssen Alfred
Published: February 2023

Reconstructing sedimentation derived from multiple source areas is complex in terms of timing and lateral variability. Moreover, untangling sediment transport and deposition in a relatively mobile plate margin is even more challenging. Here, we present results from a forward stratigraphic modelling technique that has been used to simulate basin filling of the Cenozoic succession in the Barents Sea, a tectonically active area that may have received sediments from mainland Norway, the Barents Sea shelf, and NE Greenland. We have included parameters related to tectonics and climate, and the results have been calibrated with seismic and well data. Sensitivity analyses have been performed to test different paleobathymetric reconstructions, as the study area comprises both a moving plate boundary and variable sediment source directions and fluxes.
The Cenozoic evolution of the Barents Sea shelf is strongly linked to the breakup between the Greenland and the Eurasian plates at c. 55 Ma, which led to the development of local highs and basins along the margins of the Barents Sea. This configuration resulted in the deposition of progradational wedges and submarine fans (c. 40 Ma) in the basins including the Sørvestsnaget Basin. Subsequent plate reorganization caused a renewed shelf uplift (c. 33 Ma) and opening of the Fram Strait gateway (c. 17 Ma) affected the sedimentary processes and deposits (including the introduction of contourites) in the sink, observable in seismic and borehole data. A major increase in sediment supply resulting from glacial erosion in the past 3 Myr is reflected in the deposition of several >3 km-thick trough mouth fans along the continental margin. We present ongoing work and discuss the importance of different factors controlling stratigraphic variability in basins filled by multiple source areas.
Effect of biochar application on soil hydrophysical properties and erosion potential
Authors: Roncak Peter , Nemetova Zuzana , Vitkova Justina , Botkova Natalia , Tokova Lucia
Published: February 2023

Biochar application is considered a beneficial strategy for improving soil ecosystem services and also takes place in carbon sequestration, decreasing greenhouse gas emissions, renewable energy, elimination of waste, and as a soil remedy. The literature reports that, in general, biochar application reduces runoff by 5-50% and soil loss by 11-78%, suggesting that it may be effective in reducing water erosion, but the extent of erosion reduction is highly variable. The main mechanism by which biochar can reduce water erosion is by improving soil properties (i.e., organic carbon, hydraulic conductivity, aggregate stability) that affect soil erodibility.The subject of this study is the application of a relatively new approach to estimating soil erosion in small catchment using the physically-based erosion Erosion-3D model. The model has been developed as a physically-based model for predicting soil erosion by water on agricultural land, amount of runoff and sediment concentration.  Erosion-3D model is predominantly built on physical principles and simulates surface runoff, erosion, deposition and separation of soil particles for individual events and provides a beneficial tool for simulating and quantifying soil erosion.The impact of biochar application on soil water erosion was determined for several scenarios in order to cover various condition and reflect the answer of biochar application to different soil properties. Based on the results, it can be concluded that the application of biochar has a positive effect on erosion activity to a certain extent.The positives and negatives of biochar application to different soil properties were identified and provide a useful basis for further research.Keywords: Erosion 3D model, biochar, soil water erosion, physically-based modelThis article was created with financial support from the project of the Scientific Grant Agency VEGA 2/0155/21.
Testing hydrological model for Mars using Negev desert based field observations on the Earth.
Authors: Steinmann Vilmos , Kereszturi Ákos
Published: February 2023

There are many hydrological models for normal terrestrial environments based on precipitation related erosion, but few of them work well in arid and hyper-arid conditions. These extreme arid regions can be good Mars analogue sites to test and model the conditions and laws of precipitation fed runoff and produced erosion on the Red Planet and infer to past periods. The hydrological model we have developed is primarily designed for Martian conditions and has been tested and validated in the Zafit subbasin of the Zin basin of the Negev desert, the eastern part of Israel. The calculated model data were also compared with data from hydrological models and field measurements in the area. Our applied hydrological model without precipitation data is able to estimate the main hydrographic characteristics of the sample area, such as flow discharge, flow velocity, flow depth, and the model is also able to estimate the Formation Timescale (FTS) of some surface features, as well as vertical erosion rates. The model was developed in the open source QGIS software using SAGA and GRASS GIS modules. It uses input variables that can be measured not only under terrestrial conditions but also measured or estimated under Martian conditions, and there are good quality datasets of them. Examples of such variables are the aridity index, which plays an important role in determining the flow discharge, or the density of the rock that makes up the grains, water density, gravity, and grain size classes. The model can be run on any DTM (Digital Terrain Model), the most important constraint being that the linear unit of projection used is defined in SI metres. The hydrological part of the model is complete however under continuous development, and the final model will be complemented by a further developed erosion model to simulate long term surface evolution and change, thus facilitating the understanding of not only terrestrial but also fluvial erosion produced Martian surface changes.
Characteristics of spectral fine structure in Auroral Kilometric Radiation
Authors: Taubenschuss Ulrich , Fischer Georg , Pisa David , Santolik Ondrej , Soucek Jan
Published: February 2023

Auroral Kilometric Radiation (AKR) is a special type of nonthermal radio emission that is produced along auroral magnetic field lines at several thousand kilometers altitude above Earth's surface. Strong upward currents inside the AKR source region can lead to plasma instabilities and further to electrostatic solitary waves in the form of electron holes and ion holes. These small-scale plasma structures can modify the electron distribution function which is usually supposed to amplify the free-space wave modes, introducing various kinds of fine spectral features into the AKR emission pattern. We will discuss these fine spectral features based on observations from the Cluster Wideband Receiver (WBD). Spectral fine structure in AKR is frequently observed as fast frequency-drifting bursts of emission with time scales of milliseconds, or as features drifting more slowly over several seconds or a few minutes, like the well-known striations and banded emissions. The physical properties and parameter ranges of associated electron holes and ion holes are estimated based on statistics of observed WBD spectral patterns.
Temporal variations in fumarole gas chemistry at Teide volcano, Tenerife, Canary Islands
Authors: Padrón Eleazar , Melián Gladys V. , Asensio-Ramos María , Hernández Pedro A. , Pérez Nemesio M. , Rodríguez Fátima , Amonte Cecilia , Martín Alba , D'Auria Luca , Sumino Hirochika
Published: February 2023

Monitoring the volcanic activity of Teide, the only active stratovolcano in Tenerife, the largest island of the Canary Islands, is extremely important for the prevention and reduction of the volcanic disasters of the island. As part of the geochemical monitoring of the Teide volcanic activity, during the last three decades the volcano has been the subject of a geochemical monitoring of the fumarole discharges, characterized by low flux emission of fluids with temperatures of ∼83°C, located at the Teide summit crater (Pérez et al., 1992 and 1996; Melián et al., 2012). Teide fumaroles show chemical compositions typical of hydrothermal fluids, i.e., meteoric steam dominates the gas composition, followed by CO2, N2, H2, H2S, HCl, Ar, CH4, He, and CO (Pérez et al., 1992). The temporal variations in fumarole gas chemistry at Teide volcano was useful to detect significant changes in the chemical composition of the Teide fumarole, including the appearance of SO2, and increases in the HCl and CO concentrations, one year before a seismic crisis that occurred in Tenerife Island between April and June 2004, what suggested that the associated temporal changes in seismic activity and magmatic degassing indicate that geophysical and fluid geochemistry signals in this system are unequivocally related (Melián et al., 2012). The average of the air-corrected 3He/4He ratio during the period 1991-2022 was 6.80 RA (being RA the atmospheric ratio), with the maximum value of the time series (7.57 RA) measured in August 2016, when an input of magmatic fluids triggered by an injection of fresh magma and convective mixing took place beneath Teide volcano (Padrón et al., 2021). After such input of magmatic fluids, increases in the CO2/H2O, C/S and He/CO2 ratios, a decrease in the CO/CO2 ratio were observed together with a significant increase in the seismic activity recorded in the island of Tenerife. This work highlights the important role of volcanic gases in the monitoring of volcanic activity, paying attention to different chemical and isotopic species in the fumarolic discharges. Melián G.V. et al., (2012), Bull. VolcanoL. 74, 1465–1483.Padrón E. et al., (2021), J. Geophys. Res. 126, e2020JB020318.Pérez N.M. et al., (1992), Actas de las sesiones científicas. III Congreso Geológico de España, 1, 463–467.Pérez N.M. et al., (1996), Geophys. Res. Lett. 23(24), 3531–3534.  
Last ice sheet recession and landscape emergence above sea level in east central Sweden, evaluated using 14C produced in situ in quartz
Authors: Goodfellow Bradley W. , Stroeven Arjen P. , Lewerentz Alexander , Hippe Kristina , Heyman Jakob , Lifton Nathaniel A. , Caffee Marc W. , Näslund Jens-Ove
Published: February 2023

The aim of this study is to test the Holocene relative sea-level (RSL) curve (or shoreline displacement curve) for east central Sweden using 14C produced in situ in quartz-bearing bedrock (in-situ 14C). The original RSL curve is instead based on radiocarbon dating of organic material from isolation basins. Having an accurate RSL curve is crucial from at least two aspects. In Sweden’s safety assessments for a planned spent nuclear fuel repository and for the existing repository for low- and intermediate level waste, the RSL curve is used to constrain the emergence above sea level in landscape development models. Also, the RSL is used to constrain model estimates of rates and depths of glacial and subaerial erosion from cosmogenic 10Be and 26Al produced in situ in quartz in bedrock surfaces.Avoiding vein quartz and hydrothermally altered bedrock, five samples of granitoid bedrock were taken along an elevation transect extending southwards from Forsmark, the location of the planned spent nuclear fuel repository. Because all samples derive from bedrock outcrops positioned below the highest postglacial shoreline, they target the timing of progressive landscape emergence above sea level. To further assess the accuracy of in-situ 14C dating, we took an additional five samples from bedrock outcrops 100 km west of Forsmark, above the highest postglacial shoreline. The in-situ 14C concentrations in these samples should reflect local deglaciation ages.The ten new in-situ 14C measurements provide robust age constraints that compare favorably with the original RSL curve derived from radiocarbon dating of organic material in isolation basins and with the regional deglaciation chronology. Inferences of limited rates and depths of bedrock erosion over the past 1 Myr, inferred from 10Be and 26Al inheritance and which are critically dependent on the RSL curve, therefore glean strong support from these new in-situ 14C measurements.
Impact of Atmospheric Rivers on Poleward Moisture Transport and Arctic Climate on Interannual Timescales
Authors: Kolbe Marlen , Sonnemans Jeroen , Bintanja Richard , van der Linden Eveline , van der Wiel Karin , Whan Kirien , Benedict Imme
Published: February 2023

The projected increase in poleward moisture transport (PMT) towards warmer climate has mainly been linked to the larger moisture holding capacity of warmer air masses. However, the future of interannual fluctuations of PMT and associated driving mechanisms are fairly uncertain. This study demonstrates the extent to which atmospheric rivers (ARs) explain the interannual variability of PMT, as well as related variables such as temperature, precipitation and sea ice. Such linkages help to clarify if extreme precipitation or melt events over Arctic regions are dominantly caused by the occurrence of ARs. A main focus is set on the impact of ARs on Arctic sea ice on interannual timescales, which so far has been poorly studied, and varies from colder to warmer climates.To robustly study these interannual linkages of ARs and Arctic Climate, we examine Arctic ARs in long climate runs of one present and two future climates (+2°C and +3°C), simulated by the global climate model EC-Earth 2.3. To enhance the significance of the results, three different moisture thresholds were used to detect ARs. Further, the use of additional thresholds relative to the 2°C and 3° warmer climates allowed a distinction between thermodynamic and dynamic processes that lead to changes of ARs from colder to warmer climates. It is found that most PMT variability is driven by ARs, and that the share of ARs which explain moisture transport increases towards warmer climates. We also discuss the role of the position and strength of the jet stream in driving AR variability and highlight the importance of ARs in generating interannual fluctuations of Arctic climate variables such as temperature and precipitation.
Hydrological performance evaluation of temperature reanalysis products for the Ouémé River Basin in West Africa
Authors: Jalan Ishita , Merk Fabian , Tuo Ye , Disse Markus
Published: February 2023

West Africa has a complex climate regime. It affects hydrological predictivity in the region where the majority population depends on agriculture. With a warming planet, the challenge is further exacerbated by frequent hydroclimatic extremes. To achieve secured livelihoods and resilience, hydrological understanding is a key. However, there is an elemental challenge of missing measured weather data. Weather variables that are drivers of the water and energy balance are necessary for the setup of robust hydrological models. We focus on the Ouémé River Basin in Benin, which lacks spatially representative in-situ temperature observations. To fill this gap, the study evaluates global earth datasets in the form of reanalysis products that are emerging useful for hydrological modeling. We perform an intercomparison of five temperature reanalysis datasets for the basin using the hydrological model Soil and Water Assessment Tool (SWAT). These datasets are CFSR, CPC, ERA5, EWEMBI, and PGFv3, available at a daily temporal resolution. We test their performance on the simulation of hydrological processes in the Ouémé basin.To evaluate each temperature data, a multi-site calibration is performed in SWAT using daily discharge time series. Validation is carried out as a two-fold process. The first is point validation performed using discharge data at five gauge sites and the second is spatial validation on the sub-catchment level conducted using satellite-derived actual evapotranspiration (AET) data from GLEAM v3.5b. This multi-gauge and multi-variable approach is used to minimize uncertainties associated with the application of SWAT.This study is one of a kind for the basin, testing the datasets for their hydrological performance and overcoming a major gap toward achieving robust models. Temperature reanalysis products provide high temporal resolution, long time series, and spatially representative datasets. However, the response to input data errors can vary significantly given the non-linear interaction of parameters in a hydrological model. Therefore, hydrological evaluation is an important step before reanalysis data can be used for modeling and decision-making. We also demonstrate the significance of testing multiple water fluxes to assess the performance of climate datasets. A higher variation in performance for temperature datasets is observed for AET than for the streamflow component. It is an important outcome to determine the most suitable temperature product for the Ouémé basin.
What happens to biomass burning-emitted particles in the Ocean? A laboratory experimental approach based on their tracers
Authors: González-Sánchez Juan Miguel , Panagiotopoulos Christos , Antich Candice , Van Wambeke France , Misson Benjamin
Published: February 2023

Biomass burning is a major contributor to the emission of particle matter in the atmosphere (up to 90 % of primary organic aerosol) and thus has an impact on climate, human health, and ecosystems. Once emitted, biomass burning-derived organic aerosol can be transported to the oceans. However, the impact and fate of this particulate matter and its major components in the marine biological carbon pump and the trophic chain are largely unknown. Understanding these processes is of paramount importance to better asses the carbon cycle. This work presents the first attempt to investigate the bioavailability of two biomass-burning tracers (i.e., levoglucosan and galactosan) in seawater inoculated with marine microorganisms. To do so, a novel method was developed to extract the anhydrosugar from their salty matrix and monitor their evolution for 44 days under controlled conditions. Along with the anhydrosugar concentration, multiple parameters (dissolved organic carbon, inorganic nutrient concentrations, prokaryotic production, heterotrophic prokaryotes abundance, and prokaryotic diversity) were monitored to achieve a complete picture of their fate in seawater. Furthermore, two control experiments (glucose- and non-amended) were run in parallel for comparison purposes. The results show that both levoglucosan and galactosan can be biodegraded at slow rates as their concentrations dropped from 2.5 ± 0.6 and 2.4 ± 0.3 μM to 0.1 ± 0.1 and 1.5 ± 0.7 μM, respectively, over a period of 44 days. The decrease in the levoglucosan and galactosan concentrations was accompanied by an increase in both prokaryotic production (up to 40 and 5 times greater, respectively, when compared to the non-amended experiment) and heterotrophic prokaryotes abundance (for levoglucosan, up to one order of magnitude greater than the non-amended experiment). While glucose was assimilated by heterotrophic prokaryotes within 1.7 days, levoglucosan and galactosan biodegradation did not start until at least 8.7 days after the experiments were set. These delays suggest that the chemical structure of these anhydrosugars can only be tackled by specific enzymatic abilities regulated by slow-growing heterotrophic prokaryotes. Prokaryotic diversity analyses revealed the predominance of a few bacterial genera from the Roseobacter clade that were specifically selected by the addition of the anhydrosugars. These results raise questions about the enzymatic capabilities of this widespread marine bacterial clade and the processing of semi-labile compounds accumulating in surface ocean waters. This work shows that biomass-burning organic compounds have the potential to be biodegraded by prokaryotic bacteria and thus contribute to the trophic chain and the production of CO2. 
Agricultural Soils in Spain: mapping the problems that threaten them, and the ecosystem services they provide.
Authors: Asins Sabina , Molina Mª José , Doñate Emilio
Published: February 2023

Spain, with 16,902,421 hectares under cultivation, ranks fourth in agricultural production in Europe and tenth worldwide. The weight of the agricultural sector represents 9.2% of the total GDP of the Spanish economy, and it is the sixth economy that contributes the most employment to the European agri-food sector. Knowing the risks associated with the use of agricultural soils, as well as the services that these soils provide to the ecosystem, is of great importance to address problems associated with their management. In the context of the SERENA project (Soil ecosystem services and soil threats modelling and mapping), funded by the European Joint Program on Soil (EJP-Soil), we present, on the one hand, functional indicators expressed in the form of maps of the bundles that are generated between individual soil threats:- Agricultural Soils / Soil Compaction- Agricultural Soils / Soil Erosion Rates- Agricultural Soils / Soil Drought.Or combined soil threats:- Agricultural Soil Compaction / Agricultural Soil Erosion RatesAs well as the bundles among the services that agricultural soils provide to the ecosystem, such as:- Primary production/ Organic carbon content in the soil- Agricultural Soils / Water retention capacity- Agricultural Soils / Important areas for the conservation of birds and biodiversity.These indicators can be useful in the formulation of public policies, in decision-making by end-users, and in the dissemination and transfer of knowledge by social media.
Transport of H-3 and I-129 in water and their uptake by marine organisms due to the planned release of Fukushima storage water
Authors: Bezhenar Roman , Takata Hyoe , Maderich Vladimir
Published: February 2023

The 3D model THREETOX was applied for the long-term simulation of the planned release of radioactively contaminated water from Fukushima storage tanks to marine environment. Two radionuclides were considered: 3H that has the largest activity in tanks and 129I that can caused the largest dose of radiation to human. The constant release rate of 3H equal to 22 TBq/y according to TEPCO estimations and the constant release rate of 129I equal to 361 MBq/y according to estimations from the current study were used in the simulations.The THREETOX model used monthly averaged currents from the KIOST-MOM model. A dynamic food web model was included in the THREETOX model. In the model, organisms uptake the activity directly from water and through the food chain. The food chain consists of phytoplankton, zooplankton, non-piscivorous (prey) fish, and piscivorous (predatory) fish. In case of 129I, macro-algae was also considered. The modelling area covers Fukushima coastal waters and extends for 1600 km from the coast to the East. From North to South this area extends for 1300 km.From model results, we can see how contamination will spread along the coast in different seasons. For example, in summer time the currents near the coast are directed to the North that leads to contamination of the Sendai Bay. This means that at different points along the coast, the concentration of radionuclides can periodically change according to currents that change during the year. Calculated concentrations of activity at several points along the coast of Japan, which correspond to largest cities in the area of interest, were extracted from model results. For example, calculated concentration of 3H in water in Tomioka point, which is quite close to FDNPP, sometimes can exceed 200 Bq/m3. In Soma point, the concentration will exceed 50 Bq/m3, while in point Iwaki-Onahama – 20 Bq/m3 at some moments of time. In other points, the calculated concentration of 3H in water will not exceed 10 Bq/m3 that is less than background concentration 50 Bq/m3. Concerning 129I, its maximum concentration in water will be around 10-3 – 10-2 Bq/m3 in points close to FDNPP and around 10-4 Bq/m3 in points further from the NPP that is around 100 000 times less than the calculated concentrations of 3H.Calculated concentrations of OBT (organically bounded tritium) in predatory and prey fish are less than 0.01 Bq/kg in all points except FDNPP point where it is around 0.02 Bq/kg. This value is 10 times less than measured concentration of OBT in fish (0.2 Bq/kg) that was made in 2014 in the coastal area near the damaged NPP. Calculated concentrations of 129I in predatory and prey fish are in the range 10-6 – 10-4 Bq/kg in all considered points. Concentrations of 129I in macro-algae are about 100 times higher due to ability of iodine to accumulate in macro-algae. 
Seismoelectric conversions due to a ground source in stratified porous media
Authors: Zheng Xuzhen , Ren Hengxin , Li Changcheng , Zeng Ling
Published: February 2023

The penetration and diffusion of fluids in fluid-saturated porous media can cause electromagnetic (EM) disturbances due to the electrokinetic effect. These mechanically induced EM waves, often known as the seismoelectric wave fields are sensitive to hydraulic parameters such as porosity and permeability. For in-situ seismoelectric field observations, the source and receivers are usually located at or near the ground surface. However, the current reflectivity-method-based seismoelectric modeling algorithms will suffer computational difficulties due to the slow convergence problem occurring when the source and receiver are located at close or the same depths. To overcome this problem, we extend the peak-trough averaging method to update the seismoelectric modeling algorithm based on the Luco-Apsel-Chen generalized reflection and transmission method. The updated seismoelectric algorithm is then applied to study the seismoelectric coupling phenomena. The results demonstrate that the electric signals recorded by a surface receiver are several milliseconds earlier than their causative seismic waves due to the evanescent seismoelectric conversion. This is capable to interpret similar phenomena reported in seismoelectric field observations over a long history. This time difference may have the potential to identify the location of the groundwater table. Therefore, the updated seismoelectric algorithm is a precise and efficient tool for forward modeling, which also benefits the interpretations of field seismoelectric observations.
A simple method to derive Fourier-wavelet spectra for studying global-scale waves in the mesosphere and lower thermosphere region
Authors: Yamazaki Yosuke
Published: February 2023

Global-scale waves, such as tides and traveling planetary waves, are an important part of the meteorology of the mesosphere and lower thermosphere (MLT) region. The amplitude and phase of these waves can be determined by analyzing longitude-time data given at a certain height and latitude. The standard technique is the least-squares Fourier method. However, it has difficulties in resolving the temporal variability of the wave activity. Tides and traveling planetary waves are known to show considerable temporal variability in the MLT region. In this presentation, a simple method to derive Fourier-wavelet spectra, which can resolve temporal variability of wave activity, is introduced. The technique enables to obtain a 'wavelet-like' spectrum, separately for eastward- and westward-propagating global-scale waves with different zonal wavenumbers. Application examples are presented using data from whole atmsophere models. The results suggest that the technique is capable of capturing bursts of global-scale wave activity in the MLT region during sudden stratospheric warming events.
Is the flood occurrence rate decreasing in Southeast Europe?
Authors: Leščešen Igor , Basarin Biljana , Mudelsee Manfred , Wilby Robert L.
Published: February 2023

Floods are natural phenomena, which can turn into disasters and cause widespread damage, health problems and deaths. This is particularly the case where rivers have been denied from their natural floodplains and are limited by embankments, and where housing and industrial buildings have been constructed in areas that are naturally liable to flooding. However, during the last few decades, flood observations from different parts of Europe do not show a clear increase in flood occurrence rate (Blöschl et al., 2019). In the present paper we present longer-term records of winter and summer floods in one of the largest river of Southeast Europe, the Sava River for the 1926-2021 period. We analysed three group of events that were based on three flood protection levels in Republic of Serbia defined for Sremska Mitrovica station. Regular protection level is set at 4120 m3/s and emergency flood defense level which is set at 5120 m3/s, that is, minor events are up to the regular protection level, strong events are up to the emergency level and extreme events are above emergency flood defense level. For the past 95 years, we find a decrease in both summer and winter flood occurrence rates. The reduction in winter flood occurrence can partly be attributed to reduced amount of precipitation during this period of the year. Further, on the basis of these data and methods, we find that for the Sava River can be stated the following: (1) downward but not significant trends in winter flood risk during the observed period, (2) Downward trends of summer floods was also observed, with only strong events being statistically significant. This decrease can be partially due to a projected decrease in cyclone frequency in the Mediterranean region. Presented results clearly demonstrate decreasing flood occurrence rate of the Sava River, as a consequence of decreasing precipitation and increasing evaporation (due to increasing temperature). ReferencesBlöschl, G., Hall, J., Parajka, J., Perdigão, A. P. R., Merz, B., Arheimer, B., Aronica, T. G., Bilibashi, A., Bonacci, O., Borga, M., Čanjevac, I., Castellarin, A., Chirico, B. G., Claps, P., Fiala, K., Frolova, N., Gorbachova, L., Gül, A., Hannaford, J., Harrigan, S., Kireeva, M., Kiss, A., Kjeldsen, R. T., Kohnová, S., Koskela, J. J., Ledvinka, O., Macdonald, N., Mavrova-Guirguinova, M., Mediero, L., Merz, R., Molnar, P., Montanari, A., Murphy, C., Osuch, M., Ovcharuk, V., Radevski, I., Rogger, M., Salinas, L. J., Sauquet, E., Šraj, M., Szolgay, J., Viglione, A., Volpi, E., Wilson, D., Zaimi, K. & Živković, N. (2019). Changing climate both increases and decreases European river floods. Nature 573 (7772), 108–111. https://doi.org/10.1038/s41586-019-1495-6.Acknowledgements This research was supported by ExtremeClimTwin project, which has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 952384.
Modelling 3D subsurface structures using gravity and enhanced gravity gradient method
Authors: Beránek Roman , Mrlina Jan
Published: February 2023

Keywords: salt structure, gravity inversion, density modelA gravity survey is a good choice to investigate various subsurface structures, including salt domes. We performed numerous gravity survey simulations based on synthetic and analogue geological models, but also on real survey data. We started with forward gravity/density modelling of various shapes of salt diapirs (intrusions), using not only usually measured gravity data, but also gravity gradients. The resulting data mixed with certain levels of noise was then used for the gravity inversion process. We found some limits of sensitivity to selected starting models and extreme significance of the realistic definition of starting models for geologically plausible inversion results.We applied this experience to real data – we digitized published gravity maps with negative anomalies related to salt structures. Contrary to the publication, we developed a more complex 3D model of the principal salt structure.Currently, we follow analogue modelling of a simulated salt intrusion process in a laboratory and perform gravity modelling according to the digitized shape of salt (special silicon) intruding homogenous sedimentary (sand) formations.Besides other methods, we apply 3D deterministic inversion coupled with the estimation of the starting model parameters based on the gravity gradients analysis. These parameters are mainly the dip, depth, and lateral extent. The problem is defined on a discrete rectangular mesh with the possibility of localized refinement to increase or decrease the resolution in certain parts of the model. The results provide a detailed density model of the diapir allowing the estimation of the spatial extent of the salt sheet. The usage of gravity gradients leads to the construction of more reliable starting models of near-surface salt structures for gravity inversion. Our aim is also to achieve a suitable geometrical correlation with magnetotellurics (MT), as such a twin gravity-MT response for various types of salt structures may encourage the application of such twin geophysical methodology. 
Extinction cascades, community collapse, and recovery across a Mesozoic hyperthermal event
Authors: Dunhill Alexander , Shaw Jack , Zarzyczny Karolina , Atkinson Jed , Little Crispin , Beckerman Andrew
Published: February 2023

Biotic interactions and community structure are seldom examined in mass extinction studies but must be considered if we are to truly understand extinction and recovery dynamics at the ecosystem scale. Here, we model shallow marine food web structure across a Mesozoic hyperthermal event, the Toarcian extinction, in the Cleveland Basin, UK using a trait-based inferential modelling framework. We subjected our pre-extinction community to extinction cascade simulations in order to identify the nature of extinction selectivity and dynamics. We then tracked the pattern and duration of the recovery of ecosystem structure and function following the extinction event. In agreement with postulated scenarios, we found that primary extinctions targeted towards infaunal and epifaunal benthic guilds reproduced the empirical post-extinction community. These results are consistent with geochemical and lithological evidence of an anoxia/dysoxia kill mechanism for this extinction event. Structural and functional metrics show that the extinction event caused a switch from a diverse, stable community with high levels of functional redundancy to a less diverse, more densely connected, and less stable community of generalists. Ecological recovery appears to have lagged behind the recovery of biodiversity, with most metrics only beginning to return to pre-extinction levels ~7 million years after the extinction event. This protracted pattern supports the theory of delayed benthic ecosystem recovery following mass extinctions even in the face of seemingly recovering taxonomic diversity and gives stark warnings for present day marine ecosystems affected by warming temperatures and dysoxia.
Observations and modelling of urban carbon and water fluxes to aid cities in climate mitigation and adaptation
Authors: Järvi Leena , Ahongshangbam Joyson , Havu Minttu , Lee Hei Shing , Soininen Jesse , Karvinen Esko , Karvonen Anni , Kulmala Liisa
Published: February 2023

Urban green areas have multiple benefits extending from heat mitigation and carbon sinks to human well-being. Due to their multi-benefits, they are an attractive natural solution to aid climate change adaptation and mitigation. In cities of Helsinki and Tampere located in Finland, intensive observations and modelling of urban water and carbon dioxide (CO2) fluxes have taken place to improve our understanding of the functioning and carbon sequestration potential of different urban green areas and provide science-based evidence for decision-makers on how urban green areas should be planned and constructed to maximize their climate benefits.Extensive eco-physiological observations were collected from different vegetation types (urban forest, park, garden, and street vegetation) in Helsinki during summers 2020-2022. The observations were made in the vicinity of the ICOS Associated Ecosystem Station FI-Kmp where eddy covariance (EC) measurements presenting the ecosystem level are conducted. The measurements included photosynthesis, sap flow, soil respiration, phenology, fine root growth, meteorology and soil properties. FI-Kmp represents mixed land use and vegetation, and to get more information of the behavior of lawns, additional EC measurements were conducted over urban lawn in the city of Espoo in 2021-2022. The observations are complemented by ecosystem modelling using SUEWS (Surface Urban Energy and Water balance Scheme). SUEWS is used to examine the impact of different urban green area planning options on carbon sinks and storages with focus on the city of Tampere. This work will highlight some of the findings made so far and provide examples on the carbon and water fluxes in different urban green areas. We also demonstrate how science-based knowledge can aid decision-making concerning urban green areas.