bluuebunny/crossref_metadata_2025 huggingface dataset:
Relations between DSGSDs, morphostratigraphy of landslide deposits, tectonic and climatic events in central-eastern Sardinia.
Authors: Demurtas Valentino , Deiana Giacono , Orrù Paolo Emanuele
Published: March 2020

Some cases of deep-seated gravitational slope deformations (DSGSDs) and paleo-landslides in central-eastern Sardinia are presented. This study focuses on the Quaternary landslide deposits preserved on the flanks of the Rio Pardu and Rio Ulassai valleys. The area is characterized by a wide
plateau with a prominent Jurassic limestone scarp overlying Palaeozoic metamorphites. The Plio-Pleistocenic uplift, linked to the Tirrenian basin opening and the consequent basalt volcanism, generated high slopes. In the middle-lower Pleistocene, deepening of the valley has been accelerated by
river capture processes. This litho-structural setting is prone to the development of rock falls, toppling and deep-seated gravitational slope deformations. During the upper-middle Pleistocene the gravitational and fluvial dynamics were dominated by the eustatic phases. The aim of this study is to determine the morpho-stratigraphy and main characteristics of the Quaternary landslide deposits using geomorphic, sedimentological and morphotectonic analysis. The use of high resolution UAV (Unmanned aerial vehicle) photogrammetry and geological, structural, geomorphological surveys allowed a detailed morphometric analysis and the creation of interpretative 3d models. This analysis allowed to recognize new morphostructural elements linked to a compound landslide with lateral spreading and sackung characteristics which involves giant carbonate blocks and the underlying foliated metamorphites. This high-resolution data allowed the formulation of new hypotheses about evolution and kinematics of DSGSD and landslides. The results of field surveys, geomorphological and sedimentological analysis of actual and paleo-landslide deposits show morphostratigraphic framework encompasses three order of rockfalls and three order of DSGSD. Cemented, quiescent and active landslide deposits were tentatively attributed to the Pliocene, Pleistocene and Holocene tectonic and climatic events, and compared with the traditional Quaternary stratigraphy of eastern Sardinia.
Full-waveform inversion of Ground Penetrating Radar data for target characterization in multilayer environments
Authors: Fedeli Alessandro , Pastorino Matteo , Randazzo Andrea
Published: March 2020

In the last decades, ever growing efforts have been devoted to the development of techniques for extracting information from Ground Penetrating Radar (GPR) measurements. In particular, the processed data are used to retrieve two different kinds of features. The first kind includes the so-called qualitative properties of buried targets, which are typically related to the location and/or the shape of the objects. The second kind of features is related to the quantitative dielectric characterization of the underground targets. Both strengths and weaknesses of qualitative and quantitative approaches are well known in the scientific community. Despite the more complex mathematical structure of quantitative techniques, their use is attracting an increasing attention in multiple geophysical and engineering applications.

In this contribution, the full dielectric characterization of the region of interest is retrieved by a quantitative inversion approach that works in the mathematical framework of Lebesgue spaces with variable exponents. The most important parameter of this algorithm is represented by the map of the exponent function inside the investigation domain. Here, different strategies for obtaining and refining this map in an adaptive fashion iteration-by-iteration are proposed. Numerical results are presented to check the effectiveness of the inversion approach.
Investigating the Dynamics of the Pacific Antarctic Circumpolar Current – Initial Results from International Ocean Discovery Program Expedition 383 (DYNAPACC)
Authors: Lamy Frank , Winckler Gisela , Zarikian Carlos , 383 Scientists Expedition
Published: March 2020

The Antarctic Circumpolar Current (ACC) is the world’s strongest zonal current system that connects all three major basins of the global ocean, and therefore integrates, forces and responds to global climate variability. In contrast to the Atlantic and Indian sectors of the ACC, and with the exception of drill cores from the Antarctic continental margin and off New Zealand, the Pacific sector of the ACC lacks information on its Cenozoic paleoceanography from deep-sea drilling records.

To advance our knowledge and understanding of Miocene to Holocene atmosphere-ocean-cryosphere dynamics in the Pacific and their implications for regional and global climate and atmospheric CO2, IODP Expedition 383 recovered sedimentary sequences at: (1) Three sites located in the central South Pacific (Sites U1539, U1540 and U1541); (2) two sites at the Chilean Margin (U1542, U1544); and (3) one site from the hemipelagic eastern South Pacific (U1543) close to the entrance to the Drake Passage. Age control based on magneto and bio-stratigraphically constrained orbital tuning of physical properties in the Plio-Pleistocene sediments is remarkable, with Sites U1541 and U1543 extending the record back to the late Miocene, and Site U1540 to the earliest Pliocene. Pleistocene sedimentary sequences with high sedimentation rates in the order of 40 cm/kyr were drilled in the Central South Pacific (U1539) and along the Chilean Margin. Taken together, the sites represent a depth transect from ~1100 m at the Chilean margin (U1542) to ~4070 m in the Central South Pacific (U1539), and allow reconstructing changes in the vertical structure of the ACC – a key issue for understanding the role of the Southern Ocean in the global carbon cycle- to be investigated. The sites are located at latitudes and water depths where sediments will allow the application of a wide range of siliciclastic, carbonate, and opal-based proxies to address our objectives of reconstructing, with unprecedented stratigraphic detail, surface to deep ocean variations and their relation to atmosphere and cryosphere changes through stadial-to-interstadial, glacial-to-interglacial and warmer than present time intervals.
High-sensitivity measurement of OH radicals using multi-pass enhanced Faraday Rotation Spectroscopy
Authors: Nguyen Ba Tong , Zhao Weixiong , Chen Jiajin , Liu Kun , Gao Xiaoming , Fertein Eric , Chen Weidong
Published: March 2020

The hydroxyl radical (OH) is considered as a primary agent responsible to remove a majority of trace gas in the atmosphere [1]. It is also responsible to initiate the reactions leading to the formation of a wide range of secondary species such as ozone (O3) and secondary organic aerosols (SOAs) [2]. Reliable and real-time assessment of the OH radical concentration change and related chemical process in the atmosphere is a key factor to understand and determinate the oxidation capacity of the atmosphere. Because of its very high reactivity, very short lifetime (≤ 1 s) associated with very low atmospheric concentration (~106 OH/cm3), the development of optical instrument allowing accurate, interference-free and ultra-high sensitivity in-situ direct measurement of OH concentration presents a great challenge for atmospheric science and climate change research.We report in this paper our recent development of an OH sensor based on Faraday Rotation Spectroscopy (FRS) [3]. FRS exploits magnetic circular birefringence (MCB) observed in the vicinity of Zeeman split absorption line of paramagnetic species such as O2, NO, NO2, OH. The Q(1,5e) and Q(1,5f) double lines of OH at 3568,52 cm-1 and 3568,41 cm-1 were chosen for quantification of OH radicals [4,5]. In order to enhance the detection sensitivity, multi-pass absorption approach was coupled to FRS. A 1σ (SNR=1) detection limit of about 5×107 OH/cm3 was achieved.

The experimental detail and the preliminary results will be presented and discussed. 

Acknowledgments

The authors thank the ﬁnancial supports from the CPER CLIMIBIO program and the Labex CaPPA project (ANR-10-LABX005).

 References

[1] D.E. Heard, M.J. Pilling, Chem. Rev. 103 (2003) 5163-5198.

[2] D. Stone, L.K. Whalley, and D.E. Heard, Chem. Soc. Rev. 41 (2012) 6348-6404.

[3] G. Litfin, C.R. Pollock, R.F. Curl, F.K. Tittel, J. Chem. Phys. 72 (1980) 6602-6605.

[4] W. Zhao, G. Wysocki, W. Chen, et al., Opt. Express 19, (2011) 2493-2501.

[5] W. Zhao, G. Wysocki, W. Chen, W. Zhang, Appl. Phys. B 109 (2012) 511-519.
How sociohydrology can help address the global water crisis and meet the sustainable development goals
Authors: Di Baldassarre Giuliano , Sivapalan Murugesu , Rusca Maria , Mondino Elena , Konar Megan , Pande Saket , Cudennec Cristophe , Garcia Margaret , Kreibich Heidi , Mård Johanna , Sanderson Mattew , Tian Fuqiang , Wei Jing , Yu David J. , Srinivasan Veena , Viglione Alberto , Blöschl Günter
Published: March 2020

Millions of people around the world are affected by water crises manifesting at different scales, such as increasing drought severity and flood risk, groundwater depletion, ecological degradation, poor sanitation, water pollution and its impact on human health. This global water crisis is increasingly interconnected and growing in complexity. Negative effects often result from a lack of understanding of wider economic and socio-cultural perspectives. More specifically, water crises can be deemed the intended or unintended consequences of long-term changes of social norms and values (or, more broadly, culture), ideology or political systems, which are not typically anticipated or accounted for in coping with water-related issues. Sociohydrology engages with these principles by examining the outcomes of water management and governance processes –successes and failures as well as the distribution of costs and benefits across social groups— themselves as subjects of scientific study. In this presentation, we show how feedback mechanisms between human and water systems can generate a wide range of phenomena (including crises) in different places around the world. Moreover, we argue that a generalized understanding of sociohydrological phenomena has an important role to play in informing policy processes while assisting communities, governments, civil society organizations and private actors to address the global water crisis and meet the Sustainable Development Goals, the societal grand challenge of our time.
Strengthening resilience of Cultural Heritage at risk in an extreme changing environment
Authors: Bonazza Alessandra
Published: March 2020

Natural and man-made hazards, anthropogenic effects and extreme climate change events, are persistently putting cultural heritage under pressure, with an increasing frequency over time. In addition, such disasters and catastrophes impose new and continuously changing conservation challenges and urgently needs for innovative preservation and safeguarding approach, particularly during extreme climate conditions. The present contribution aims at illustrating the working methodology and the solutions specifically dedicated to the safeguarding of cultural heritage exposed to extreme climate changes, developed within the Interreg Central Europe ProteCHt2save and in further implementation within the Interreg Central Europe STRENCH (starting date 1st March 2020).  The outcomes (WebGIS tool, for risk mapping, hazard maps, methodology for vulnerability ranking, strategies for disaster risk reduction) of both projects are principally dedicated to assists local stakeholders in improving their know-how on the process of definition of priorities of intervention and strategies within the risk management cycle (preparedness/emergency/recovery). By the achievement of the planned objectives, ProteCHt2save and STRENCH are expected to proactively

target the needs and requirements of stakeholders and policymakers responsible for disaster mitigation and safeguarding of cultural heritage assets and to foster the active involvement of citizens and local communities in the decision-making process.
First quantitative estimation of growing methane release from the East Siberian Arctic seas: from a single flare to vast seepage area
Authors: Chernykh Denis , Shakhova Natalia , Kosmach Denis , Ananiev Roman , Salomatin Aleksander , Yusupov Vladimir , Sergienko Valentin , Gustafsson Örjan , Jakobsson Martin , Mayer Larry , Saluk Anatoly , Dmitrevsky Nikolay , Kurilenko Arcady , Gershelis Elena , Silionov Vyacheslav , Lobkovsky Leopold , Mazurov Alexey , Semiletov Igor
Published: March 2020

Sustained release of methane (CH4) to the atmosphere from thawing Arctic permafrost may be a positive and significant feedback to climate warming. Atmospheric venting of CH4 from the East Siberian Arctic Shelf (ESAS) was recently reported to be on par with flux from the Arctic tundra; however, the future scale of these releases remains unclear. Here, based on results of our 12 years observations, we show that CH4 emissions from this shelf to be determined by the state of subsea permafrost degradation. Below we consider dramatically growing release from the area located out of known fault zones.

First time, we observed CH4 emissions from this single flare in 2007 in the ESAS mid-shelf.  During 2014-2018 we revisited this area several times aiming to investigate quantitatively changing CH4 ebullition. The data show transformation of a single CH4 flare in a significant seepage area. CH4 emissions from this area emerge from largely thawed sediments via strong flare-like ebullition, producing fluxes that are orders of magnitude greater than fluxes observed in background areas underlain by largely frozen sediments. We suggest that progression of subsea permafrost thawing is much faster not only downward, but also laterally which could result in a significant increase in CH4 emissions from the ESAS.

This work was supported in part by grants from Russian Scientific Foundation (№15-17-20032, № 18-77-10004, №19-77-00067), grant from Russian Government (Grant No. 14, Z50.31.0012/03.19.2014) and Tomsk Polytechnic University Competitiveness Enhancement Program grant, Project Number TPU CEP_SESE-299\2019.
Spatial organization of soil microaggregates
Authors: Lehndorff Eva , Meyer Nele , Radionov Andrey , Plümmer Lutz , Rottmann Peter , Spiering Beate , Amelung Wulf , Dultz Stefan
Published: March 2020

The physical arrangement of soil compounds in microaggregates is important in many ways, e.g. by controlling soil stability and C sequestration. However, little is known about the spatial arrangement of organic and inorganic compounds in soil microaggregates, due to the lack of in-situ analyses in undisturbed material. Here we hypothesize that microaggregates are spatially organized, resulting in deterministic, predictable spatial patterns of different organic matter and mineral phases and that this organization depends on the abundance of specific phases such as on clay mineral content. We separated the water stable, occluded large and small microaggregate fractions from Ap horizons of a sequence of sandy to loamy Luvisols (19 to 35% clay, Scheyern, Germany) and subjected in total 60 individual aggregates to elemental mapping by electron probe micro analysis (EPMA), which recorded C, N, P, Al, Fe, Ca, K, Cl, and Si contents at µm scale resolution. Spatial arrangements of soil organic matter and soil minerals were extracted using cluster analyses. We found a pronounced heterogeneity in aggregate structure and composition, which was not reproducible and largely independent from clay content in soil. However, neighborhood analyses revealed close spatial correlations between organic matter debris (C:N app. 100:10) and microbial organic matter (C:N app. 10:1) indicating a spatial relationship between source and consumer. There was no systematic relationship between soil minerals and organic matter, suggesting that well-established macroscale correlations between contents of pedogenic oxides and clay minerals with soil organic matter storage do not apply to soil microaggregates.
Is aerosol optical depth a good metric to map dust properties? Lessons learned from AER-D
Authors: Marenco Franco , Ryder Claire , Estelles Victor , O'Sullivan Debbie
Published: March 2020

The main observable quantity used on a global scale to map aerosols is aerosol optical depth (AOD), from ground-based and satellite remote sensing. It is at the same time an optical property and a vertically integrated quantity, and it is commonly used as the main metric towards which to pull aerosol models, through data assimilation, verification, and tuning. Here we introduce a few reflections on how to better constrain our knowledge of the Saharan Air Layer and its associated mineral dust, following results from the AER-D campaign.

AER-D was a small field experiment in the Eastern Atlantic during August 2015, based on the opportunity given by the simultaneous ICE-D experiment. The purpose of AER-D was to investigate the physical properties of the Saharan Air Layer, and to assess and validate remote sensing and modelling products. The FAAM atmospheric research aircraft was used as a flying laboratory, and it carried a full set of instruments aimed at both in-situ sampling and remote sensing.

A broad distribution of particle sizes was consistently observed, with a significant giant mode up to 80 µm, generally larger than what was observed in previous experiments: we ascribe this to the set of instruments used, able to capture the full spectrum. We will discuss the representation of the particle size in operational models, and we will show that despite predicting an extinction coefficient of the correct order of magnitude, the particle size is generally underestimated. We will also discuss the implication of the giant particles for the ground-based remote sensing of columnar size-distributions from the SKYNET and AERONET networks (Sunphotometer Airborne Validation Experiment, which was a component of AER-D).

We will present the vertical structure of the Saharan Air Layer, and in particular one episode when the structure was very different than the one generally accepted in the conceptual model. Moreover, the comparison with the operational models showed that they can predict a correct aerosol optical depth (AOD, a vertically integrated quantity) despite missing the vertical distribution.

These findings lead to a series of reflections on how to better constrain our knowledge of the Saharan Air Layer and its representation in operational models. Size-resolved properties and the vertical distribution are essential companions of the global AOD observations commonly used operationally. We will also discuss objectives and ideas for future field experiments.
A Roadmap for Arctic Observing and Data Systems
Authors: Larsen Jan Rene , Starkweather Sandy
Published: March 2020

A changing Arctic

In recent decades, sustained observations of Arctic environmental and socio-economic systems have revealed a pace, magnitude, and extent of change that is unprecedented by many measures. These changes include rapid depletion of the cryosphere, shifts in ecological communities that threaten biodiversity and increasing challenges to food security and resilience across northern communities.

 

The Sustaining Arctic Observing Networks (SAON)

SAON is a joint initiative of the Arctic Council and the International Arctic Science Committee (IASC). It was created to strengthen multinational engagement in and coordination of pan-Arctic observing. SAON’s intent is to unite Arctic and non-Arctic countries and Indigenous Peoples in support of a systematic network of activities through structured facilitation.

 

A Roadmap for Arctic Observing and Data Systems (ROADS)

In its recent strategic plan, SAON identified the need for a Roadmap for Arctic Observing and Data Systems (ROADS) to set a course for the needed system and to specify how the various partners and players are going to collectively work towards getting it there. The purpose of ROADS is to stimulate multinational resource mobilization around specific plans with clear value propositions, to serve as a tool for the joint utilization of Indigenous Knowledge and science, to coordinate engagement and to ensure that maximal benefits are delivered. A well-defined assessment process is required to establish a communal view of “societal benefit”, and a key tool for such assessment will be The International Arctic Observing Assessment Framework (IAOAF) following the First Arctic Science Ministerial.

Continuing multinational coordination through SAON was endorsed by the Second Arctic Science Ministerial in their Joint Statement with an emphasis on: “moving from the design to the deployment phase of an integrated Arctic observing system”.

 

Essential Arctic Variables

SAON has identified the essential variable strategy as a best practice for supporting network development. The approach is conceptually holistic, yet can proceed step-wise as essential variables achieve readiness. ROADS will be organized around Essential Arctic Variables (EAVs). These are conceptually broad observing categories (e.g. “sea ice”) identified for their criticality to achieving Arctic societal benefit. EAVs are defined by their observing system requirements (e.g. spatial resolution, frequency, coverage, accuracy), which are technology-neutral and should transcend specific observing strategies, programs or regions. They are implemented through specific recommendations based on best available technology and practices.
The Observation Facility Catalogue – an overview of the SIOS research infrastructure on Svalbard
Authors: ignatiuk dariusz , Jennings Inger , Ferrigni Lara , Godøy Øystein , Jawak Shridhar , Lihavainen Heikki , Andersen Bo , Hübner Christiane
Published: March 2020

Svalbard Integrated Arctic Earth Observing System (SIOS) is an international consortium to develop and maintain a regional observing system in Svalbard and the surrounding waters. SIOS brings observations together into a coherent and integrated observational programme that will be sustained over a long period. Within SIOS, researchers can cooperate to access instruments, acquire data and address questions that would not be practical or cost effective for a single institution or nation alone. By bringing many types of observations together and asking questions about how these observations are influenced by each other, SIOS generates new insights about the Svalbard region’s role in the Earth system.  Thus, SIOS offers unique opportunities for research and the long-term acquisition of fundamental knowledge about global environmental change.

SIOS facilitates access to Earth System Science (ESS) data from Svalbard through a free and open data portal that enables the users to search, retrieve, visualise, transform, and harvest ESS data relevant to Svalbard stored in the distributed data centres of SIOS partners. The Observation Facility Catalogue (OFC) is a part of SIOS data portal which allows collecting and sharing information about research infrastructures distributed in Svalbard.

The OFC gives an overview of existing, planned and historic observation facilities,which collect SIOS data. An observation facility can be one instrument or a collection of instruments. The annotation is standardised based on WMO standards as far as possible, in order to make entries unambiguous and interoperable internationally.

The purpose of the OFC is to make better use of the existing research infrastructure by facilitating the search for given parameters and their location.  In this way, duplication can be avoided and new measurements can be co-located with existing ones. The catalogue has a map interface and advanced search function.  The search interface allows users to search for GCMD keywords or to filter by status, type or observatory.
Ground deformations associated with underground coal-mining observed by Sentinel-1 SAR images in vegetated area
Authors: Zhang Yonghong , Wu Hong’an , Luo Yong , Kang Yonghui , Fan Hongdong
Published: March 2020

Coal is the largest energy source for China, and over 90% coal production in China is from underground mining. However, underground mining usually trigger large-scale ground deformations, which tend to develop as hazards. Therefore, the central government of China issued the “green mine” policy in 2017, which requires to strictly implement scientific and orderly exploitation and keeping the disturbance to the mining area and surrounding environment within the limits of sustainable development in the whole process of coal mining. This policy necessitates accurate monitoring of ground deformations induced by underground mining. Satellite Interferometric SAR (InSAR), especially the multi-temporal InSAR techniques have been successfully used to monitor deformations associated with underground mining. But temporal decorrelation still remains a big challenge because many underground mining takes place beneath farmland or forested region. Given the advantages of Sentinel-1 (S-1) in short revisit time, small baselines and free accessibility, underground mining deformations can be monitored somehow with S-1 InSAR in vegetated areas. In this research we report such an application in an underground coal-mine site located in Xuzhou, Jiangsu province of China. Four working panels are investigated

The working panels are all beneath farmland where winter wheat is sowed before the end of October and reaped around next late May, then corn or rice is planted during the coming summer season from June to September. Therefore the C-band S-1 interferograms can keep good coherence only when both images are acquired in the period of late October to next early April (this period is called coherent period thereafter) when the newly planted winter wheat is in its early growing stage. Three subsets of S-1 images acquired during three consecutive coherent periods  are used to generate mining-induced ground deformations.

During each coherent period, all of the interferograms with 12-day separation and some of the interferograms with 24-day separation and good coherence are selected and phase-unwrapped. Then these two sets of unwrapped interferograms are stacked, and finally the temporal deformations along SAR line-of-sight (LOS) are calculated under the least square principle. The temporal and spatial characteristics of the LOS deformation time series (DTS) are analyzed by considering extraction stage and extraction parameters of the working panel. Based on the analysis, we can diagnose whether the underground exploitation overstepped its designed boundary, or whether the working panel has been exploited for longer time than the designed extraction period.

 
Global Agricultural Costing and Investment model
Authors: Vittis Yiorgos , Obersteiner Michael
Published: March 2020

Increasing competing demands for land, water and energy along with increasing word population call for strategies to minimise environmental impacts while producing adequate food for 9 billion people. Studies have highlighted trade-offs between yields, biodiversity and socioeconomic goals in alternative land management solutions that share or spare agricultural land, pointing out the necessity of demand-side adjustments to meet environmental and food security goals. On the contrary, research has demonstrated that agricultural intensification through sparing and sharing agricultural land at global scales has the capacity to close yield gaps, reduce land requirements and increase biodiversity. Here we address the fundamental question: Would agricultural systems produce adequate food under a land sharing and targeted sparing scenario at lower financial costs? Optimal allocation of agricultural production, based on biophysical constraints, enables increased efficiencies and thus, we hypothesize that production is going to be less costly at global scales. To address this question, a cost engineering method is employed using crop modelling and inventory data on 16 crops to assess financial implications of sharing and sparing production scenarios. Preliminary findings demonstrate that at national scales, where there are potentials for greater and more efficient food production, there is larger spatial aggregation of production systems and thus higher costs that relate to large inputs of nutrients required to close yield gaps. Further forthcoming research will allow the identification of financial balances at global scales and enable the present study to confirm that current production volumes can be maintained at lower financial and environmental costs.
Pathways of microplastics in soils - Detection of microplastic contents in compost using a thermal decomposition method
Authors: Wiesner Yosri-Kamal , Müller Axel , Bannick Claus Gerhard , Bednarz Marius , Braun Ulrike
Published: March 2020

The ubiquitous presence of unintended plastics in the environment has been an issue in scientific studies and public debate in the last years. It is well known that oxidative degradation and subsequent fragmentation, caused by UV-radiation, aging and abrasion lead to the decomposition of larger plastic products into microplastics (MP). Possible effects of these MP on ecosystems are still unclear. Recent studies on MP findings are focused mainly on aquatic systems, while little is known about MP in terrestrial ecosystems. Fermentation residues, sewage sludge and compost represent an input path of plastics in soils through targeted application in agriculture. For this reason, analysis of the total content of plastic in organic fertilizers as a sink and source of MP in ecosystems is of high interest.

In 2017, approximately 14.2 million tons of biodegradable waste were collected, from which 3.9 million tons of compost was produced. Improper waste separation result in plastic fragments in the biowaste, some of which end up in the compost and might be degrade to MP. In Germany, compost is used as fertilizer in agriculture and landscape design, hence MP could enter the soil by this pathway. Spectroscopic methods such as Raman or FTIR are not suitable for determining the mass content of microplastic, as these output a particle number.

Therefore, we show the application of ThermoExtractionDesorption-GasChromatography-MassSpectrometry (TED-GC-MS) as a fast, integral analytical technique, which in contrast to the spectroscopic methods does not measure the number of particles but a mass content. The sample is pyrolyzed to 600°C in a nitrogen atmosphere and an excerpt of the pyrolysis gases is collected on a solid phase adsorber. Afterwards, the decomposition gases are desorbed and measured in a GC-MS system. Characteristic pyrolysis products of each polymer can be used to identify the polymer type and determine the mass contents in the present sample. This method is well established for the analysis of MP in water filtrate samples. Here, we will first demonstrate the use of TED-GC-MS for compost.

This current study will also give inside in various important aspects of sample preparation, which include a meaningful size fractionation, a necessary density separation regarding the removal of inorganic contents and at finally a homogenization.
Analysis, prevalence and impact of microplastics in freshwater and estuarine environments: an evidence review
Authors: Jones John Iwan , Murphy John Francis , Arnold Amanda , Pretty James Laurence , Spencer Kate , Markus Adriaan Albert , Vethaak Andre Dick
Published: March 2020

We used the systematic review procedure to assess the evidence available on the analysis, prevalence and impact of microplastics in freshwater and estuarine environments. As the study of microplastics in freshwaters is relatively new, measurement methods are yet to be standardized, and a wide variety of methods of variable robustness have been used. Critically, the sampling methodology used in the literature had a systematic influence on the concentration of microplastic particles returned. The volume of water sampled varied over many orders of magnitude, and there was a direct relationship between the size of the smallest particles studied and the volume of water sampled in both freshwater and estuaries: large volumes of water can only be sampled using nets of relatively coarse mesh, which in turn do not capture smaller particles. Consequently, the mean abundance of microplastic particles reported was inversely correlated with both the volume of water sampled and the size of particles studied.

The size of microplastic particles had a substantial and overriding effect on threshold concentrations above which microplastics affect freshwater and estuarine biota. For the ecotoxicological endpoints of feeding, behaviour, growth and survival there was a clear relationship between the size of the particles used in the test and the threshold concentration at which an effect was seen. Although the taxonomic coverage of test organisms was limited, there were sufficient data to test the influence of taxonomic group used on size-specific thresholds for Crustacea, fish and algae. There was no significant effect of either the endpoint measured or the taxonomic group used, suggesting that there might not be any difference in sensitivity among different taxa.

In order to establish a threshold concentration where microplastics present a hazard to a limited number of taxa, quantile regression was used to determine the size-specific concentration of microplastics that was lower than 90% of the thresholds identified for survival and, as a more conservative limit, across all endpoints tested including sublethal effects. By comparing these thresholds with the data on concentrations of microplastics reported by field studies, it was apparent that the calculated size specific threshold concentration for lethal effects was considerably higher than 99% of reported environmental concentrations. Lethal effects of microplastics on freshwater and estuarine biota are likely to be limited to exceptional circumstances. Over certain size ranges the calculated size specific threshold concentration for sublethal effects was exceeded by the highest 10% of concentrations reported from environmental samples, suggesting that there is a risk of sublethal effects in a small proportion of sites.

 
Soil map of Khnifiss lagoon and GIS mapping of 2nd-order depressions in southwestern Morocco
Authors: Elbelrhiti Hicham , Roskin Joel , Bookman Revital , Oubbih Jamal
Published: March 2020

The geology and geomorphology of Moroccan Atlantic Sahara are dominated by a tabular coastal platform at altitudes of 30-35 m and a Hamada carbonate tableland with altitudes between 200 to 250 m. The coastal platform is marked by the presence of many depressions like sabkhas, lagoons while 2nd-order depressions (dayas) locally known as Grara dominate the tableands. The studied region is situated in the Saharan bioclimatic level characterized by the scarcity of precipitation.

Khnifiss, the biggest lagoon in the Moroccan Atlantic coast is the most important wetland in the Atlantic Moroccan desert. Former studies focused on sedimentary, hydrology, pollution and ecology of the lagoon, but its soil has not been mapped. Here we map the subaqueous sediment and soils of the submerged area and the soil of its surrounding areas based on remote sensing completed by field work and laboratory analysis. The soil classification system is the French Référentiel Pédologique 2008 (RP 2008). We also present a landscape map, which constitutes the first step toward a soil map, and a regional soil map at the scale of 1:150,000. The soil map shows the dominance of weakly developed soils both in fluvio-marine and aeolian dominated environments.

We also present GIS- mapped shape, morphology, size and land use of about 300 2nd-order depressions in a defined 100 sq km of a carbonate plateau. The mapping identified different types of geomorphic, hydrological and agricultural activity that lead to different types of Graras. The total area occupied by Grara covers only 3.2% of the studied area.
Quantification of Regional Risk from Failure of Earth Dam
Authors: Um Jeong Ah , Lee Sungsu , Ham Hee Jung
Published: March 2020

In order to predict the loss and the damage from the hazards such as debris flow resulted from dam failures, three important factors must be taken into account; the strength of hazard, the inventory and the vulnerability of the inventory to the hazard. In the case of the debris flow, the flow speed, the inundation boundary and depth, and the flow force can be the hazard. The inventory corresponds to the list of assets and demographic distribution while the vulnerability is the probability of the damage of each inventory by the specified hazard. In this study, the hazard is assessed from 3D numerical simulation of the debris flow incurred by the dam failure. Since the detail description and modeling of the inventory is nearly impossible, the present study utilized GIS-based regional assessment of the vulnerability combined with the inventory, in which the distribution of the inventory represents the exposure and the performance of the inventory such as age of building represents the sensitivity. As an example, building vulnerability index is measured by combining weighted five proxy variables; density of hazard exposed area of building, building importance level, type of building structural material, status of building structural design, and deterioration level of building. The selected proxy variables are evaluated with predefined scoring criteria and nondimensionalized based on a standardization method. The resulting vulnerability is normalized for the relative assessment with the region of interests. The computed strength of the hazard is then convoluted with the normalized vulnerability and the results show the risk of the region. This research was supported by a grant (2018-MOIS31-009) from Fundamental Technology Development Program for Extreme Disaster Response funded by Korean Ministry of Interior and Safety(MOIS).
Studying deep rooting and its value for crops
Authors: Thorup-Kristensen Kristian
Published: March 2020

Water and nutrients are distributed throughout the soil volume, and their ability to move towards the plant roots is highly restricted, in most cases to a few mm or less. This mean, that unlike the aboveground resources of light and CO2 moving to the plants, roots need to grow towards the resources. Thus, for efficient resource uptake, roots need to be well distributed in the soil, both locally within the root zone and to grow deep to increase the overall volume of soil exploited. In crop production, deep rooting has been shown to be highly important for water and nitrogen use, and deep rooting is expected to contribute specifically to soil C sequestration.

Research into deep rooting and its functions is strongly restricted by the difficulties of studying roots hidden deeply in the soil. It is very laborious to access them, and even more difficult to set up experiments giving frequent and non-destructive measurements of the relevant parameters.  

In previous experiments, we have studied deep rooting of crops and cover crops and its effect on deep nitrogen uptake. By measuring roots and soil nitrogen to 2.5 m depth, we found that deep rooting was a main factor in nitrogen uptake and the reduction of nitrogen leaching loss. This showed how deep rooted species can be used to develop nitrogen efficient cropping systems. Further, it was shown that inclusion of deeper soil layers in the studies were critical for the conclusions to be drawn. Increasing the depth of study from e.g. 1 m to 2.5 m did not just moderate the conclusions and quantitative estimates, in several studies it basically changed conclusions that could be drawn.

Since 2015, we have built three new research platforms dedicated to detailed study of deep root growth and function. We have built a rhizobox facility consisting of 24 rhizoboxes each 4 m deep. The rhizoboxes are equipped with soil water sensors, and give access to observe the roots, take soil and root samples and inject tracers along the whole soil profile. In the field, we have built a platform, aimed at giving similar research possibilities, using long minirhizotrons, soil water sensors and metal access tubes for inserting ingrowth cores, all together giving valuable opportunities, though we cannot achieve the same easy access to the root zone as in the rhizoboxes. Finally, we have built a deep root phenotyping facility, using minirhizotrons to allow screening of 600 plant lines for root growth down to 3 meters depth, and allowing us to measure root activity of the lines by deep placement of isotope tracers.

These new facilities, and the research opportunities they give will be discussed, together with some of the first research results on deep roots we have obtained there.
From tree to stand: Scaling relationships of water uptake and climate in a reclaimed boreal mixedwood stand.
Authors: Merlin Morgane , Landhäusser Simon M. , Carey Sean K.
Published: March 2020

Soil water availability is a key factor in determining tree’s transpiration and sap flow rates, and varies with topography and soil depth. Reclaimed landscapes provide us with the unique opportunity to address the effects of those two variables independently on trees’ water uptake, and their relationship to climatic variation. We explored the relationship between individual tree water uptake and atmospheric variables for trembling aspen (Populus tremuloides) and white spruce (Picea glauca), and assessed how this relationship changed across different hillslope positions and rooting space. Growing season (May to September) sap and transpiration fluxes were monitored using heat ratio method sap flow sensors on trembling aspen and white spruce trees in 2014 and 2015 on a reclaimed hillslope in northern Alberta, Canada, with two different soil cover depths providing different rooting spaces. Both species’ sap flow rates and transpiration rates were strongly correlated to climatic variables such as vapor pressure deficit, precipitation events, air temperature, with slight differences in the relationship between topographical positions and soil depths. Site-level atmospheric water fluxes were obtained through eddy covariance measurements at the top of the hillslope. This allowed for a direct linkage of individual tree water uptake measurement to water flux measurements taken at the landscape-level. Understanding how distinct rooting and physiological characteristics of tree species and their growing conditions can be extrapolated to different scales, is crucial to our understanding of both atmospheric and edaphic water fluxes.
Using the silica isotope composition of biogenic materials in marine sediments to reconstruct ocean chemistry
Authors: Conley Daniel , Hendry Katherine
Published: March 2020

The silicon isotopic composition of sedimentary biogenic opal can be used to track shifts in the balance between silicon inputs to the ocean and outputs by burial. In addition to biosilicification and opal burial, the global cycles of climate (hydrology, weathering, glaciation, etc.), tectonics (volcanoes, LIPs, mountain building, etc.) and geochemistry (reverse weathering, inorganic Si precipitation, etc.) have driven variations in the global Si cycle over geologic time. Prior to the start of the Phanerozoic it is thought that burial in the global oceans was controlled inorganically through chert formation. The evolution of the Si depositing organisms, radiolarians and sponges, reduced oceanic dissolved Si, but the largest reductions occurred with the evolution of the diatoms bringing dissolved Si to the low concentrations (relative to saturating concentrations) observed today. However, the timing of the depletion of dissolved Si by diatoms is currently under debate.

 

Our understanding of the biological components of the Si cycle has grown enormously. In the last decade, silicon isotope ratios (expressed as δ30Si) in marine microfossils are becoming increasingly recognised for their ability to provide insight into silicon cycling. In particular, the δ30Si of deep-sea sponge spicules has been demonstrated to be a useful proxy for past dissolved Si concentrations. However, more recent studies find anomalies in the isotopic fractionation of sponge spicules that relate to skeletal morphology: reliable reconstructions of past dissolved Si can only be obtained using silicon isotope ratios derived from sponges with certain spicule types. We are applying δ30Si proxies from biosiliceous material contained in sediments to generate robust estimates of the timing and magnitude of dissolved Si drawdown. We will provide fundamental new insights into the drawdown of dissolved Si and other key events, which reorganized the distribution of carbon and nutrients in seawater, with implications for productivity of the biological communities within the ancient oceans. 
Thermo-rheological structure of the northern margin of the South China Sea: structural and geodynamic implications
Authors: Hu Jie , Tian Yuntao , Long Zulie , Hu Di , Huang Yuping , Wang Yibo , Hu Shengbiao
Published: March 2020

Rheological properties of continental lithosphere are key controls on the behavior of continental deformation. Using thermal structure, constrained by surface heat flow data and measured thermal properties of rocks, the present study calculates different thermo-rheological structure scenarios for the ocean–continent transition (OCT) at the northern margin of the South China Sea, using two different models: a conventional model, taking into account frictional sliding and power-law creep, and a model that additionally includes a high-pressure brittle-fracture mechanism. Two compositions of the lower part of the lithosphere are considered: a soft case with felsic granulite lower crust and wet peridotite lithospheric mantle, and a hard case with mafic granulite lower crust and dry peridotite lithospheric mantle. The former scenario shows a major rheological change from a “jelly sandwich” to a “Christmas tree” type of rheology from north to south along the margin. This complex rheological structure explains lateral changes in earthquake distribution and geometries of extensional faults of the OCT at the northern margin of the South China Sea. Further, our analyses indicate that the initial lithospheric rheology profile probably has only one ductile layer in the lower part of upper crust. Such an initial lithospheric rheology model predicts focused extension to form asymmetric margins, which is the case for the SCS.

Keywords: Ocean-continent transition; Crustal strength; Thermo-rheology; South China Sea; Pearl River Mouth basin
Detecting Cyber-Physical Attacks in Water Distribution Systems: One-class Classifier Approach
Authors: Housh Mashor , Kadosh Noy , Frid Alex
Published: March 2020

Water Distribution Systems (WDSs) are critical infrastructures that supply drinking water from water sources to end-users. Smart WDSs could be designed by integrating physical components (e.g. valve and pumps) with computation and networking devices. As such, in smart WDSs, pumps and valves are automatically controlled together with continuous monitoring of important systems' parameters. However, despite its advantage of improved efficacy, the automated control and operation through a cyber-layer can expose the system to cyber-physical attacks. One-Class classification technique is proposed to detect such attacks by analyzing collected sensors' readings from the system components. One-class classifiers have been found suitable for classifying "normal" and "abnormal" conditions with unbalanced datasets, which are expected in the cyber-attack detection problem. In the cyber-attack detection problem, typically, most of the data samples are under the "normal" state, and only small fraction of the samples can be suspected as under-attack (i.e. "abnormal" state). The results of this study demonstrate that one-class classification algorithms can be suitable for the cyber-attack detection problem and can compete with existing approaches. More specifically, this study examines the Support Vector Data Description (SVDD) method together with a tailored features selection methodology, which is based on the physical understanding of the WDS topology. The developed algorithm is examined on BATADAL datasets, which demonstrate a quasi-realistic case study and on a new case study of a large-scale WDS.