bluuebunny/crossref_metadata_2025 huggingface dataset:
How not to miss a great opportunity? A closer look at teaching geosciences in formal education systems
Authors: Zawiejska Joanna , Świętek Agnieszka
Published: March 2021

Pre-university education is the most comprehensive channel of communicating verified and uniform science information to young people. Despite this foundational role, how that science is taught in schools seems often overlooked, with more attention devoted to the efficacy of alternative education pathways. We argue that effective formal science education is crucial as it nurtures future willingness to embrace new scientific information, shapes perceptions, and promotes “intellectually sustainable” attitudes towards the abiotic environment and its dynamic nature. In particular, inquiry-based teaching is necessary for students to be open to life-long learning and critical thinking as adults when they inevitably confront the effects of climate change, increasing risks from natural hazards, environmental change and simultaneous expansion of social media as a basic, if not primary, source of information about the world. Based on the analysis of Polish education system and curricula, and on interviews with geosciences teachers participating in targeted workshops, we identify systemic aspects of formal education that influence effectiveness of science communication likely to affect student attitudes, with particular regard to geohazards, related risks and to environmental protection. Factors that influence effectiveness of that education include (i) adequate knowledge transfer between fast-developing geosciences and the education system, (ii) progress in geosciences education and didactics research, (iii) long-term teacher training, (iv) progress in development and availability of innovative education tools, (v) development, construction and topicality of geosciences curricula content, (vi) degree of freedom by the teachers in interpretation and following the curriculum content, and (vii) consistency in curriculum content throughout the education cycle and across subjects that include geosciences topics. Coordination of these aspects is challenging, especially since each is designed, driven, supervised and often financed by different actors. Particular attention should be given to the timely incorporation of current scientific knowledge into school curricula to avoid significant time lags in the content of communicated information and resultant collation of contradictory messages that students receive. Finally, we emphasize the urgent need for development of post-diploma education programmes and similar initiatives that will support geosciences teachers
Use of crushed bark of Picea abies as a soil conditioner in organic spring wheat production
Authors: Nurmi Elina , Kurki Päivi , Haikarainen Iina , Savikurki Riitta , Kaseva Janne , Hakala Kaija , Valkama Elena
Published: March 2021

Adding organic matter in the soil is especially important for organic agriculture, which relies on good soil health for plant production. Crushed bark (CB) of Picea abies (L.) Karsten is a forestry by-product, which has been developed into a new soil conditioner for organic farming. It contains up to 80 % organic matter with C/N ratio of 78 and pH 5.7-6.0, but is rather nutrient poor.

Organic field experiments on loamy sand with moderate soil fertility took place in Mikkeli, Finland in 2017-2018 in order to test the substance. The fertilization was based on commercial organic fertilizers: chicken manure and blood meal fertilizer in the first year and meat and bone meal fertilizer in the second one. The treatments were control (only fertilization) and one- or two-year applications of CB (40 t ha-1) with or without base ash (4 t ha-1). Other half of plots were left without substances in 2018.

No differences between treatments were observed without the base ash in any of years. A one-year application of crushed bark with base ash increased both spring wheat yield quantity and quality. The statistically significant effects were found for yield, N uptake, grain protein content, 1000-seed weight and hectolitre weight compared to control in 2018, a year after application. Despite the severe drought during that growing season, the wheat yields for CB with base ash and control were 3100 kg ha-1 and 2250 kg ha-1, respectively. The positive effects of soil amendments were not as clear in the first year as in the following. No benefits were visible after two-year successive application of CB either alone or with base ash. Spruce CB in addition with base ash may be beneficial in terms of yield and quality when it is applied only once in large amounts. In our study the effects were overall greater in the following year after the application.
Spontaneous initiation of debris flow surges from sedimentary deposits
Authors: Wang Baoliang , Li Yong , Guo Xiaojun
Published: March 2021

Spontaneous initiation of debris flow surges from sedimentary deposits

Wang Baoliang1 , Li Yong2, Guo Xiaojun2

1 Yellow River Engineering Consulting Co., Ltd., Zhengzhou, 450004, China

2 Key Laboratory of Mountain Hazards and Surface Process / Institute of Mountain Hazards and  Environment, Chinese Academy of Sciences, Chengdu, 610041, China

 

We report here that a small gully of sedimentary deposit has spontaneously produced a sequence of debris flow surges in great variety of appearances. The event occurred in a tributary gully of 0.16km2, without slope failures and rainstorms; the only triggering force was the groundwater at small discharge (0.5L/s). Individual surges originated separately from the sediment in different manners and appeared in a variety of flow regimes and material compositions(Fig.1). We’ve taken a detailed scrutiny on the whole processes, i.e., the surge sequence spontaneously occurring in the stream (Fig.2), and suggested a mechanism for the surge scenario. It is proposed that the sediment is heterogeneously composed of blocks of granular aggregates, featured by the grain size distribution (GSD). With different GSD parameters, sediment blocks have different critical condition of liquefaction or fluidization, which determines the manner of surge initiation (Fig.3). Fine grains are easily to run out with infiltration to form slurry and lubricate the substrate sediment layer, facilitating the mobility of succeeding surges; while coarse grains collapse as Coulomb failure and turn into high concentrated surges. And variation of the substrate granular structure causes on and off of the surges. In summary, it is the randomness of GSD and block of sediment that lead to the variety of surge initiation; and the initiation and motion of tributary surges provides a vivid scenario for intermittent surges in the mainstream channel.

 
Analysis of mine sites restoration strategies for soil and water resources protection
Authors: Pacetti Tommaso , Lompi Marco , Caporali Enrica
Published: March 2021

Mine reclamation represents an important environmental challenge due to the necessity of identifying the appropriate restoration measures to handle landscape change and minimize the associated environmental impacts. Water management plays a key role for determining strategies to reduce these impacts, e.g. necessity of restoring natural drainage patterns, implementing flood control measures and restoring hydrological natural behaviour. Fundamental aspects are certainly represented by the runoff variation and the proper sediment management.

The objective of this study is to give quantitative evidence on the effectiveness of decommissioning strategies on water and sediment management. The selected case study is a former lignite mining site located in San Cipriano catchment (Tuscany, central Italy) that include a reservoir severely hit by silting problems. The Soil Water Assessment Tool (SWAT) was used to analyse current situation and to implement different LULC changes analysis. Since hydrometric gauge stations were not available in the catchment, the model calibration focused on sediment transport using observed silting volume in the reservoir, which has been estimated thanks to multiple bathymetric campaigns carried out over the years. Two environmental restoration scenarios have been analysed: the first is focused on the land use change with the afforestation of the former mining site with native plants; the second is a wider landscape restoration project that also includes river bodies rehabilitation.

Results highlight a strong reduction of sediment yield and a decrease in water yield associated to the restoration intervention. This is mainly due to the effects of reforestation that influence the hydrological cycle inducing an increase of water storage in the soil and determine a strong reduction of sediment input to the reservoir. The model results represent a valuable decision support tool that help understanding the hydrological impacts of LULC changes, supporting the identification of the most appropriate mining decommissioning strategies.
How to combine climate models and observations in event attribution?
Authors: Robin Yoann , Ribes Aurélien
Published: March 2021

We describe a statistical method to derive event attribution diagnoses combining climate model simulations and observations. We fit nonstationary Generalized Extreme Value (GEV) distributions to extremely hot temperatures from an ensemble of Coupled Model Intercomparison Project phase 5 (CMIP)
models. In order to select a common statistical model, we discuss which GEV parameters have to be nonstationary and which do not. Our tests suggest that the location and scale parameters of GEV distributions should be considered nonstationary. Then, a multimodel distribution is constructed and constrained by observations using a Bayesian method. This new method is applied to the July 2019 French heatwave. Our results show that
both the probability and the intensity of that event have increased significantly in response to human influence.
Remarkably, we find that the heat wave considered might not have been possible without climate change. Our
results also suggest that combining model data with observations can improve the description of hot temperature
distribution.
Covariability of trade-wind cloudiness and environmental conditions in large-eddy simulations and observations
Authors: Schulz Hauke , Eastman Ryan , Stevens Bjorn
Published: March 2021

Shallow convection in the downwind trades occurs in form of different cloud patterns with characteristic cloud arrangements at the meso-scale. The four most dominant patterns were previously named Sugar, Gravel, Flowers and Fish and have been identified to be associated with different net cloud radiative effects.

By using long-term observations, we reveal that these differences can be mainly attributed to the stratiform cloud component that varies in extent across the patterns as opposed to the cloudiness at the lifting condensation level that is fairly constant independent of the patterns.

The observations reveal further, that each pattern is associated with a different environmental condition whose characteristics originate not soley from within the trades. Sugar air-masses are characterized by weak winds and of tropical origin, while Fish are driven by convergence lines originating from synoptical disturbances. Gravel and Flowers are most native to the trades, but distinguish themselves with slightly stronger winds and stronger subsidence in the first case and greater stability in the latter.

How well this covariability of cloudiness and environmental conditions is represented in simulations is important to project the occurrence of the patterns in a warmer climate and evaluated by realistic large-eddy simulations of the recent EUREC4A field campaign.
Interplay of volcanotectonic, sedimentary, and regional tectonic processes at Mount Etna’s submerged south-eastern flank
Authors: Urlaub Morelia , Bonforte Alessandro , Geersen Jacob , Gross Felix , Pandolpho Bruna
Published: March 2021

Collapses of coastal and ocean island volcanoes can cause damaging tsunamis and thus pose ocean-wide hazards. To assess the collapse hazard of an unstable flank, a profound understanding of its structural setting and active deformation is essential. This knowledge is, however, often missing, especially for the remote and submerged offshore part of the edifice. Long before satellite-based techniques were available, observations of extensional structures in the summit region and transpressive to compressional structures farther downslope helped to constrain flank instability onshore at many volcanoes globally. Similar deformation structures are also expected offshore where they might be even better preserved due to the absence of anthropogenic influence, limited weathering and erosion. However, in the offshore realm structures related to flank instability are masked by and interact with other processes that act on underwater slopes, such as bottom currents, downslope sediment transport, and regional tectonics. Furthermore, the remote location of offshore flanks complicates geophysical, geomorphological, and geological investigations. Using (micro-) bathymetric and high-resolution seismic data we analyse the seascape forming processes at the Eastern Sicily continental slope at the foot of Mount Etna's unstable south-eastern flank. We untangle seafloor structures related to volcanotectonic, sedimentary, and regional tectonic processes. This allows singling out patterns and structures related to volcano flank instability, such as the lateral and outward boundaries of the unstable flank. We identify a strike-slip fault that changes its morphological appearance from a sharp linear feature atop a pressure ridge north of Catania Canyon to an almost smooth seafloor further downslope, where gravitational sediment transport outbeats volcanotectonic activity. Sediment transport from the continent to the abyss occurs along several canyons and channels that partly align with fault systems. Furthermore, uplift at the distant toe of Etna‘s south-eastern flank may indicate compression from the downwards moving flank, while at the same time provoking erosional responses, e.g. landslides. This new information provides important constraints for kinematic models that seek to explain the drivers of flank instability. It also forms the base for future studies that will infer the styles and rates of offshore flank deformation from the geological record.
Arctic MIZ Sensitivity to Atmosphere- Ice-Ocean Feedbacks
Authors: Frew Rebecca , Feltham Daniel , Schroeder David , Bateson Adam
Published: March 2021

Over the past few decades, as the summer Arctic sea ice cover has been shrinking, the marginal ice zone (MIZ) has been widening. Projections indicate that the majority of the sea ice cover will become marginal (here defined as that region with ice area fractions between 0.15 and 0.8) over the next few decades. The impact of the change in atmospheric forcings on the sea ice cover and MIZ between the 1980s and the 2010s is evaluated using a coupled sea ice (CICE)-mixed layer model, that includes a prognostic floe size-thickness distribution (FSD) model. As the MIZ accounts for a greater fraction of the sea ice cover, some feedbacks with the atmosphere and ocean are expected to strengthen. The role of sea ice feedbacks with the atmosphere and ocean in response to the change in atmospheric conditions between the 1980s to the 2010s are evaluated using feedback denial simulations. In particular: i) the albedo feedback; ii) feedbacks associated with changes to mixed layer stratification (including changes in mixed layer properties) and therefore the ocean heat flux to the sea ice; and iii) changes to the lateral melt rate due to decreasing floe sizes. 
Value assessment of ornamental stone resources
Authors: Heldal Tom , Aasly Kari Aslaksen
Published: March 2021

Throughout Europe, there are large industrial and cultural landscapes originating from the exploitation of ornamental stone through history. Such landscapes may contain a range of potential values; economic, such as future resources and reserves, and non-economic, such as cultural and industrial heritage, areas for recreation and tourism, and geological heritage. Based on case studies in two areas, we will explore different paths and methods for assessing values of ornamental stone resources.

The Iddefjord granite, SE Norway, has been exploited since the middle ages, but the main phase came with the industrial revolution. During the last half of the 19th Century, the granite industry here grew to a considerable size, culminating around the turn of the century when more than 5000 people worked in the quarries, producing paving and building stone. At present time, only one active natural stone quarry remains, but the quality of the granite should encourage further future developments. The study summarizes the geology and evolution of quarrying and quarry technology and provides a characterization of the quarry landscape: its resources that can provide economic values for the future and the anthropogenic morphology of the landscape created by exploitation through history. From the characterization, we propose a scheme for value assessment of the Iddefjord natural stone resource. In particular, we focus the non-economic values. For instance, the importance of the Iddefjord granite as a historic marker in world architecture may provide significant arguments for future designation of exploitation areas.

The Larvik monzonite (larvikite) in SE Norway is composed of varieties of monzonite with a distinct play of colour (chatoyancy), making the stone highly attractive in the global markets. Although use of larvikite goes back to the medieval period, industrial production started in the Late 19th Century and is still large scaled and increasing. This case study investigates the future resources, applying 3D modelling and UNFC. In addition, secondary value chains from the primary ornamental stone production are evaluated.

These case studies are parts of the Eurolithos and Mintel4EU Projects within the GeoEra umbrella, aimed at harmonizing and visualizing information about natural stone resources in Europe.
Stratification effects on shoaling Internal Solitary Waves
Authors: Hartharn-Evans Sam , Carr Magda , Stastna Marek , Davies Peter
Published: March 2021

Shoaling is a key mechanism by which Internal Solitary Waves (ISWs) dissipate energy, induce mixing, and transport sediment. Past studies of shoaling ISWs in a three-layer stratification (with homogeneous upper and lower layers separated by a thin pycnocline layer) have identified a classification system where waves over the shallowest slopes undergo fission, whilst over steeper slopes, the breaking type changes from surging, through collapsing to plunging as a function of increasing internal Irribaren number (Ir) defined with the topographic slope, s, and the incident wave’s amplitude and wavelength, Aw and Lw respectively, as <img src="https://contentmanager.copernicus.org/fileStorageProxy.php?f=gnp.9fb46536f70067154311161/sdaolpUECMynit/12UGE&app=m&a=0&c=d84eaf790c6586a46ed8fca09040fcd7&ct=x&pn=gnp.elif&d=1" alt="" width="117" height="24">. Here, a combined numerical and laboratory study extends this prior work into new stratifications, representing the diversity of ocean structures across the world. Numerical results were able to successfully reproduce past studies in the three-layer stratification, and those in the two-layer stratification in the laboratory. Where a linear stratified layer overlays a homogeneous lower layer (two-layer stratification), it is found that plunging dynamics are inhibited by the density gradient throughout the upper layer, instead forming collapsing-type breakers. In numerical experiments, where the density gradient is continuous throughout the full water column (linear stratification), not only are the plunging dynamics inhibited, but the density gradient at the bottom boundary also prevents the formation of collapsing dynamics, instead all waves in this stratification either fission, or form surging breakers. Where the wave steepness is particularly high in the linear stratification, the upslope bolus formed by surging was unstable, and Kelvin-Helmholtz instabilities were observed on the upper boundary of the bolus, dynamics not previously observed in the literature. These results indicate the importance of using representative stratifications in laboratory and numerical studies of ISW behaviours.
The ILRS Contribution to ITRF2020
Authors: Luceri Vincenza , Pavlis Erricos C. , Basoni Antonio , Sarrocco David , Kuzmicz-Cieslak Magdalena , Evans Keith , Bianco Giuseppe
Published: March 2021

The International Laser Ranging Service (ILRS) contribution to ITRF2020 has been prepared after the re-analysis of the data from 1993 to 2020, based on an improved modeling of the data and a novel approach that ensures the results are free of systematic errors in the underlying data. This reanalysis incorporates an improved “target signature” model (CoM) that allows better separation of true systematic error of each tracking system from the errors in the model describing the target’s signature. The new approach was developed after the completion of ITRF2014, the ILRS Analysis Standing Committee (ASC) devoting almost entirely its efforts on this task. The robust estimation of persistent systematic errors at the millimeter level permitted the adoption of a consistent set of long-term mean corrections for data collected in past years, which are now applied a priori (information provided by the stations from their own engineering investigations are still taken into consideration). The reanalysis used these corrections, leading to improved results for the TRF attributes, reflected in the resulting new time series of the TRF origin and especially in the scale. Seven official ILRS Analysis Centers computed time series of weekly solutions, according to the guidelines defined by the ILRS ASC. These series were combined by the ILRS Combination Center to obtain the official ILRS product contribution to ITRF2020.

The presentation will provide an overview of the analysis procedures and models, and it will demonstrate the level of improvement with respect to the previous ILRS product series; the stability and consistency of the solution are discussed for the individual AC contributions and the combined SLR time series.
Investigation of Mechanical and Thermal Wind Sensitivity on the Mesoscale Eddies in the Southern Ocean
Authors: Tutak Bilge , Ilicak Mehmet , Mazloff Matthew
Published: March 2021

In this study, a high-resolution eddy resolving regional ocean + sea ice coupled model (MITgcm) is used to study the effects of increasing westerlies along the Southern Ocean. Previous studies only focused on increasing wind stress, thus not taking into account of atmosphere-to-ocean heat and freshwater fluxes. Here, we conduct two concurrent simulations; i) 1.5 times increased wind stress (i.e. increased only mechanical forcing) ii) 1.2247 times increased wind speed (i.e. both mechanical and thermal flux forcing). Model domain covers whole Southern Hemisphere with lateral open boundary conditions from ECCOv2 ocean reanalysis and surface boundary conditions from ECMWF ERA-5 atmospheric reanalysis. In both sensitivity scenarios, due to the increase in the wind stress, the Ekman transport towards Equator towards north is increased. This caused increased upwelling of warmer North Atlantic Deep Water (NADW) near the Antarctic ice sheet. Both scenarios show reduced sea ice formation with up to 2 million km2 in the austral summer and up to 4 million km2 during the austral winter. Sea ice extent is reduced more in the mechanical forcing simulation than the mechanical+thermal forcing one. This is a clear result that increased wind anomalies should be studied with increased wind rather than increased stress. The reduction in the sea ice coverage that is attributed to the warmer water mass can also be observed through the Sea Surface Temperature (SST) values. The first case shows up to 1 – 1.5 °C very close to the Antarctica, whereas the second case shows a much limited SST change around 0.5 °C.

Both sensitivity scenarios show an increase of the transport along Drake Passage. However, the mechanical+thermal case shows larger increase in the Drake transport compared to the mechanical case. This indicates that a change in the Antarctic Circumpolar Circulation also modifies the meridional density gradient along with the upwelling characteristics. Finally, overturning transport in the density space shows that Subtropical Cell and ACC upper Cell strengthen in the mechanical+thermal case, while there are no significant changes in the thermal case. In both simulations, Subpolar Cell increases and Lower Cell decreases. We conclude that studying increased westerlies with two different approaches show significant changes in the surface and deep circulation. Previous studies which taken into only mechanical forcing part are missing thermal component of the wind effects.
Solving the long-standing problem of estimating the atmospheric temperature at 90 km altitude with meteor radar
Authors: Sarkar Emranul , Ulich Thomas , Virtanen Ilkka , Lester Mark , Kaifler Bernd
Published: March 2021

For two decades meteor radars have been routinely used to monitor atmospheric temperatures around the 90 km altitude. A common method, based on a temperature-gradient model, is to use the height dependence of meteor decay time to obtain a height-averaged temperature in the peak meteor region. Traditionally this is done by  fitting a linear regression model in the scattered plot of  log10(1/tau) and height, where ’tau’ is the half-amplitude decay time of the received signal. However, this method was found to be consistently biasing the slope estimate. The consequence of such bias is that it produces a  systematic offset in the estimated temperature, and thus requiring calibration with other colocated measurements. The main reason for such a biasing effect is thought to be due to the failure of the classical regression model to take into account the measurement error in decay time or the observed height. This is further complicated by the presence of various geophysical effects in the data, as well as observational limitation in the measuring instruments. We demonstrate an alternative regression method that incorporates various error terms in the statistical model. An initial estimate of the slope parameter is obtained by assuming symmetric error variances in normalised height and log10(1/tau). This solution is found to be a good prior solution for the core of this bivariate distribution. However, depending on the data selection process the error variances may not be exactly equal. A first-order correction is then carried out to address the biasing effect due to asymmetric error variances. This allows to construct an analytic solution for the bias-corrected slope coefficient for this data. With this solution, meteor radar temperatures can be obtained independently without using any external calibration procedure. When compared with colocated lidar measurements, the temperature estimated using this method is found to be accurate within 7% or better and without any systematic offset.
Nitrogen enrichment of animal bone-derived biochars as an agricultural NP-fertilizer 
Authors: Soja Gerhard , Tauber Dominik , Höllrigl Jan , Mayer Andrea , Pfeifer Christoph
Published: March 2021

Food processing creates many by-products, and not all of them are used efficiently. Especially animal-based side products are frequently considered as waste with costly disposal requirements. For recycling of the nutrients contained in these residues, also under consideration of the hygienic specifications, pyrolysis can be used to create animal bone-based biochars. A lab-scale pyrolysis reactor (Pyreka 3.0) was used to produce biochars from different bone fractions of cattle and pigs after these bones had originated as waste from abbatoir operations. This study had the objective to investigate the potential of the bone chars to serve as a phosphorus (P) supply for agricultural purposes and to study the ammonium sorption potential of these chars.

The total phosphorus content of bones reached up to 140 mg/g. The water-soluble phosphorus content was in the range of 0.16 – 0.93 mg/g, an increase in pyrolysis temperature from 350 °C to 500 °C or 650 °C increased the water-soluble content by 13.3 or 12.2 % respectively. The citric acid soluble phosphorus content was between 1.75 – 2.19 mg/g. After pyrolysis temperatures of 350 °C, slightly more phosphorus dissolved in the coal products than at 500 °C (+2.7 %) and at 650 °C (+5.5 %).

The ammonium sorption capacity of biochars produced by varying pyrolytic processes was investigated by a series of sorption experiments. The removal of ammonium by the biochars from an aqueous ammonium solution was measured by using colorimetric determination of the ammonium content. The maximum ammonium sorption results were achieved by biochars produced from bovine heads and feet respectively at a temperature of 900°C and activated with H2O.

When exposed to a solution containing 50 mg/L of ammonium, these biochars adsorbed 1.23 and 1.14 mg ammonium/g biochar, respectively. The possibility to enrich abattoir waste biochars, which are depleted in nitrogen because of the pyrolysis process, with ammonium gained from a nitrogen-enriched biogas slurry produced from animal residues of the meat production process was tested using a substitute slurry made with ammonium sulfate. The highest absorbance rate using the substitute slurry containing 10 g/L ammonium was achieved by biochar made from bovine heads and resulted in 43.1 mg ammonium/g biochar.

This study shows that bone-based biochars enriched with nitrogen from e.g. biogas digestates have significant potential as an NP-fertilizer that supports the strategies of circular economy.
Multiple-channel Singular Spectrum Analysis-based noise reduction for MT data observed in Boso Peninsula, Japan
Authors: Kaneko Shu , Hattori Katsumi , Mogi Toru , Yoshino Chie
Published: March 2021

Off the coast of the Boso Peninsula, there is a triple junction of the Pacific Plate, the Philippine Sea Plate, and the North American Plate and the Boso Peninsula is one of the seismically active areas in Japan. There are also epicenter areas such as the 1703 Genroku Kanto Earthquake (M8.2), the 1923 Taisho Kanto Earthquake (M7.9), and the Boso Slow Slip which occurs every 6 years, which are geologically interesting places. To estimate the subsurface resistivity structure of the whole Boso area, Magnetotelluric (MT) survey with 41 sites (inter-sites distance of 7 km) has been conducted in 2014-2016, using U43 (12 sites, 1 Hz sampling ; Tierra Technica) and MTU-5, 5A, net (41 sites, 15, 150, and 2400 Hz sampling; Phoenix Geophysics). However, the Boso area is greatly affected by leak current from DC-driven trains, factories, and power lines, so the observed data are contaminated by artificial noises. When we tried to apply the conventional noise reduction method (e.g., remote reference (Gamble et al., 1979) and BIRRP (Chave and Thomson, 2004)) in frequency domain, the obtained MT sounding curve was not ideal. In particular, the phase between the periods of 20 and 400 sec was close to 0 degrees. It suggests that the method used is insufficient to reduce the near-field effect for the Boso data. Thus, we developed a new noise reduction method using MSSA (Multi-channel Singular Spectrum Analysis) as a pre-processing method in time domain.

The procedure is as follows;

(1) Decompose 6 component data (Hx, Hy, Ex, Ey, Hxr and Hyr: H and E means magnetic and electric field, respectively, x and y indicates NS and EW component, and r denotes the reference field observed at a quiet station) using MSSA into 6×M principal components (PCs).  Here, M shows the window length of MSSA.

(2) Check contribution and periods of each PC and eliminate the PCs which are corresponding to the longer periods of variation. That is “detrend” of the original data.

(3) Apply the second MSSA to the detrended time series data to separate signals and noises shorter than 400 sec.

(4) Calculating correlation coefficients between H and Hr and between E and Hr for each PC and select the PCs with higher correlation to reconstruct time series data to make MT analysis.

Then, we perform MT analysis by BIRRP to estimate apparent resistivity,

As a result, the coherences of H-Hr, and E-Hr were improved and the MT sounding curve became smoother than those results by the conventional noise reduction methods. This indicated that the effectiveness of the proposed noise reduction. However, further investigation in different periods and sites will be required.
The uranium isotopic composition of modern stromatolites forming in Shark Bay, Western Australia
Authors: Martin Ashley N. , Markowska Monika , Chivas Allan R. , Weyer Stefan
Published: March 2021

Stromatolites represent some of the earliest evidence for life and are valuable geochemical archives for understanding the rise of oxygen on early Earth. Metal redox proxies in carbonates, such as stable uranium isotopes (238U/235U), are useful for assessing the oxidation state of ancient waterbodies, but may also be sensitive to local water chemistry and early sedimentary diagenesis. This requires the validation of such proxies in modern environments before applying them to ancient carbonates. Here we measure the U isotopic composition of modern stromatolites forming in Hamelin Pool in Shark Bay, Western Australia – a large hypersaline marine embayment and the largest modern example of stromatolite development globally. Actively-growing stromatolite tops from Shark Bay exhibited a narrow range of δ238U from -0.30 to -0.33‰, corresponding to an offset of ca. +0.1‰ from seawater. Such an offset has not been found in other biotic marine carbonates, which exhibit seawater-like δ238U (ca. -0.4‰), but is consistent with findings from carbonate co-precipitation experiments. One hypothesis for our measured +0.1‰ offset is the elevated Ca concentration of the hypersaline Shark Bay seawater relative to open seawater. This results in a greater proportion of dissolved U present as Ca2UO2(CO3)3, which is expected to be isotopically lighter than other U species and not incorporated during carbonate mineral formation. Higher δ238U up to +0.11‰ were measured in the deeper stromatolite laminae, consistent with the expected U isotope signatures for U reduction. Stromatolite radiocarbon ages show that the diagenetic modification of U occurs within ~1 ka and may be considered syndepositional on geological timescales. These results from the deeper stromatolite laminae support the application of a ca. -0.4‰ correction factor to the δ238U of stromatolites formed in oxic waterbodies, similar to other biotic carbonates. It is unclear whether the additional +0.1‰ offset found in stromatolite tops is particular to seawater chemistry of Shark Bay or a general feature of microbial carbonate precipitation. This warrants investigation of the δ238U proxy in other modern environments where stromatolites proliferate.
Inorganic polymers of ground waste concrete and industrial waste slags as a low-cost sorbent of heavy metals
Authors: Vavouraki Aikaterini
Published: March 2021

Inorganic polymers (IPs) are alkali activated aluminosilicate materials. Research on the synthesis of alternative cementitious materials such as IPs receives substantial attention not only for their physico-chemical properties that they acquire but for being cost-effective components of the future toolkit of sustainable construction materials (Provis, 2018; Vavouraki, 2020). In addition to potential uses of alkali activation materials for the disposal of industrial solid wastes and by-products, there is a great scientific interest in deploying IPs for environmental remediation purposes (Rasaki et al., 2019). In particular IPs can possess application value in pollution treatment of immobilization of toxic (and/ or nuclear) wastes, both inorganics and organics (Ji & Pei, 2019). Green sustainable aluminosilicate-based adsorbents may facilitate the elimination of toxic metal and organic pollutants from water and/ or wastewater (Tan et al., 2020). IPs are considered low-cost sorbents not only for successful recycling of waste materials but also considering added-value materials for the removal of heavy metals from aqueous solutions. However limited number of studies examines waste-slag-based IPs for the removal capacity of heavy metals.

The aim of this study is to synthesize IPs from ground waste concrete and industrial slags and investigate their uptake capacity for heavy metals from aqueous solutions. The calcite-bearing and industrial-slags IPs as sorbent materials were examined for the uptake of solely Cu(II), Zn(II) and, Pb(II) and also or along with competitive aqueous solutions. Kinetics and equilibrium experiments were performed and analytical techniques involving XRF, XRD, FTIR, SEM/ EDS and XPS were used for the characterization and morphology analysis of the produced IPs.

References: Ji & Pei, 2019. J. Environ. Manage. 231, 256–267; Provis, 2018. Cem. Concr. Res. 114, 40–48; Rasaki et al., 2019. J. Clean. Prod. 213, 42–58; Tan et al., 2020. Environ. Technol. Innov. 18, 100684; Vavouraki, 2020. J. Sustain. Metall. 6, 383–399.
Metabarcoding of modern sedimentary DNA from the Tibetan Plateau and Siberia as a training dataset for vegetation reconstructions
Authors: Jia Weihan , Stoof-Leichsenring Kathleen , Liu Sisi , Li Kai , Huang Sichao , Liu Xingqi , Ni Jian , Cao Xianyong , Pestryakova Luidmila , Mischke Steffen , Herzschuh Ulrike
Published: March 2021

Lake sedimentary DNA (sedDNA) is an established tool to trace past changes in vegetation composition and plant diversity. However, little is known about the relationships between sedimentary plant DNA and modern vegetational and environmental conditions. In this study, we investigate i) the relationships between the preservation of sedimentary plant DNA and environmental variables, ii) the modern analogue of ancient plant DNA assemblages archived in lake sediments, and iii) the usability of sedimentary plant DNA for characterization of terrestrial and aquatic plant composition and diversity based on a large dataset of PCR-amplified plant DNA data retrieved from 259 lake surface sediments from the Tibetan Plateau and Siberia. Our results indicate the following: i) Lake-water electrical conductivity and pH are the most important variables for the preservation of plant DNA in lake sediments. We expect the best preservation conditions for sedimentary plant DNA in small deep lakes characterized by high water conductivities (≥100 μS cm-1) and neutral to slightly alkaline pH conditions (7–9). ii) Plant DNA metabarcoding is promising for palaeovegetation reconstruction in high mountain regions, where shifts in vegetation are solely captured by the sedDNA-based analogue matching and fossil pollen generally has poor modern analogues. However, the biases in the representation of some taxa could lead to poor analogue conditions. iii) Plant DNA metabarcoding is a reliable proxy to reflect modern vegetation types and climate characteristics at a sub-continental scale. However, the resolution of the trnL P6 loop marker, the incompleteness of the reference library, and the extent of sedDNA preservation are still the main limitations of this method. iv) Plant DNA metabarcoding is a suitable proxy to recover modern aquatic plant diversity, which is mostly affected by July temperature and lake-water conductivity. Ongoing warming might decrease macrophyte richness in the Tibetan Plateau and Siberia, and ultimately threaten the health of these important freshwater ecosystems. To conclude, sedimentary plant DNA presents a high correlation with modern vegetation and may therefore be an important proxy for reconstruction of past vegetation.
Inferring significant wave height from seismic data: A comparison between methods.
Authors: Bolrão Francisco , Tran Co , Lima Miguel , Sheriffdeen Sheroze , Rodrigues Diogo , Silveira Graça , Bui-Thanh Tan , Custodio Susana
Published: March 2021

The most pervasive seismic signal recorded on our planet – microseismic ambient noise -results from the coupling of energy between atmosphere, oceans and solid Earth. Because it carries information on ocean waves (source), the microseismic wavefield can be advantageously used to image ocean storms. This imaging is of interest both to climate studies – by extending the record of oceanic activity back into the early instrumental seismic record – and to real-time monitoring – where real-time seismic data can potentially be used to complement the spatially dense but temporally sparse satellite meteorological data.
In our work, we develop empirical transfer functions between seismic observations and ocean activity observations, in particular, significant wave height. We employ three different approaches: 1) The approach of Ferretti et al (2013), who compute a seismic significant wave height and invert only for the empirical conversion parameters between oceanic and seismic significant wave heights; 2) The classical approach of Bromirski et al (1999), who computed an empirical transfer function between ground-motion recorded at a coastal seismic station and significant wave height measured at a nearby ocean buoy; and 3) A novel recurrent neural-network (RNN) approach to infer significant wave height from seismic data. 
We apply the three approaches to seismic and ocean buoy data recorded in the east coast of the United States. All three approaches are able to successfully predict ocean significant wave height from the seismic data. We compare the three approaches in terms of accuracy, computational effort and robustness. In addition, we investigate the regimes where each approach works best.  The results show that the RNN approach is able to predict well the significant wave height recorded at the buoy. The prediction is improved if several nearby seismic stations are used rather than just one. 
This work is supported by FCT through projects UIDB/50019/2020 – IDL and UTAP-EXPL/EAC/0056/2017 - STORM.
Inter-annual variations and large-scale atmospheric forcing on ice thickness and composition during the last decade in an Arctic lake 
Authors: Cheng Bin , Cheng Yubing , Vihma Timo , Zheng Fei
Published: March 2021

A thermistor-string-based Snow and Ice Mass Balance Apparatus (SIMBA) was deployed in an Arctic lake Orajärvi in northern Finland (67.36°N, 26.83°E) during winter seasons 2011/2012 - 2019/2020. The snow depth and ice thickness (total and separately for congelation ice and granular ice) were retrieved from SIMBA temperature measurements. The average maximum ice thickness was 72 cm with a standard deviation of 10 cm. The interannual variability of lake ice composition was large. In the past 3 ice seasons, the granular ice dominated the total ice thickness. For example, granular ice accounted 80% of the total ice thickness in May 2020. A high-resolution thermodynamic snow/ice model was applied to simulate ice mass balance, with special attention to the lake ice composition. Local weather station data and ECMWF reanalysis products were used as model forcing.

 

The increase of granular ice formation is a result of more snow precipitation during the ice season, increased variability of seasonal air temperature, and a warming trend. The observed snow thickness on land showed a high correlation with snow-ice thickness on top of lake ice. The relationships between the ratio of snow-ice to total ice thickness and the large-scale atmospheric circulation indexes were investigated. Precipitation and, consequently, snow ice thickness on Lake Orajärvi correlated with the phase of the Pacific Decadal Oscillation, which is in line with previous results for precipitation and ice conditions in northern Finland, but an eventual causal teleconnection still requires further studies.

 
Drivers of spatial and temporal soil water isotope variability in a sub-arctic catchment
Authors: Muhic Filip , Ala-Aho Pertti , Marttila Hannu , Klöve Björn
Published: March 2021

Research on ecohydrological separation and plant water use have been increasing in the last few years, and various studies indicate that trees can use winter precipitation as a dominant water source during the growing season. Such studies are of great importance to northern regions, where soil water recharge timing is predicted to be significantly altered due to climate change. In order to assess plant water use in sub-arctic environment, it is necessary to understand how soil water pools under different land covers evolve throughout the year and how cryogenic processes alter the isotope input signal. This field study was conducted from May 2019 to June 2020 in Pallas catchment, located in sub-arctic conditions in Finnish Lapland. Soil cores up to 1 meter depth with 5 cm increments and xylem water of dominant tree species were collected in 4 locations, ranging from forest to shrubland/forest transitional area, and to forested peatland. All locations are positioned on a snow survey, in the vicinity of previously installed groundwater wells and snow lysimeters, and within 2 kilometers of rain gauge. Additional spatial samples of topsoil and xylem water were collected throughout the catchment during 2019 growing season. Relative proportions of tree source water were calculated by Bayesian mixing model MixSIAR. We produce new data set that displays plot and catchment scale soil water heterogeneities in a snow dominated environment, and examine: i) How soil properties affect isotopic composition of soil water?; ii) What is the effect of rising groundwater level on soil water isotope composition?; and iii) How snowpack thickness and melt timing modify soil water isotope patterns? We analyze if these varying pools of water are reflected in tree xylem water. Soil water isotope dynamics under deep snowpack, during and after snowmelt reveal how snow accumulation and melt timing and magnitude influence plant available water for growing season.