Newsfeed

    • Geosciences, Vol. 9, Pages 239: Coastal Flood Assessment due to Sea Level Rise and Extreme Storm Events: A Case Study of the Atlantic Coast of Portugal’s Mainland

      Portugal’s mainland has hundreds of thousands of people living in the Atlantic coastal zone, with numerous high economic value activities and a high number of infrastructures that must be adapted and protected from natural coastal hazards, namely, extreme storms and sea level rise (SLR). In the context of climate change adaptation strategies, a reliable and accurate assessment of the physical vulnerability to SLR is crucial. This study is a contribution to the implementation of flooding standards imposed by the European Directive 2007/60/EC, which requires each member state to assess the risk associated to SLR and floods caused by extreme events. Therefore, coastal hazard on the Atlantic Coast of Portugal’s mainland was evaluated for 2025, 2050, and 2100 over the whole extension due to SLR, with different sea level scenarios for different extreme event return periods. A coastal probabilistic flooding map was produced based on the developed probabilistic cartography methodology using geographic information system (GIS) technology. The Extreme Flood Hazard Index (EFHI) was determined on probabilistic flood bases using five probability intervals of 20% amplitude. For a given SLR scenario, the EFHI is expressed, on the probabilistic flooding maps for an extreme tidal maximum level, by five hazard classes ranging from 1 (Very Low) to 5 (Extreme).

    • Geosciences, Vol. 9, Pages 238: How Glaciers Function and How They Create Landforms: Testing the Effectiveness of Fieldwork on Students’ Mental Models—A Case Study from the Sanabria Lake (NW Spain)

      This paper analyzes the impact of fieldwork on the development of students’ mental models concerning glaciers and their effects on the landscape. Data were collected by means of an open-ended questionnaire that was administered to 279 pre-service teachers before and after an educational field trip, which analyzed its impact on short-term and long-term outcomes. In general, students’ mental models about how glaciers function and how they create landforms are relatively simplistic and incomplete. Students are unaware of the major erosional properties associated with glaciers and many of them do not specify that glaciers are bodies of ice that have a tendency to move down slope. The analysis of the data yielded four mental model categories. Fieldwork influenced the short-term effects on mental model development even though its positive impact decreases over time. Mental models including scientific views were only found in the post-instruction group. On the other hand, the pre-instruction group was strongly influenced by a catastrophic event that occurred in the region in 1959 (the Ribadelago flooding), which interferes with students’ mental reasoning on the formation of landscape features. This way of thinking is reinforced and/or mixed with a religious myth (Villaverde de Lucerna legend), which also invokes a catastrophic origin of the lake. In this case, this includes mystic flooding.

    • Geosciences, Vol. 9, Pages 237: How Do Continuous High-Resolution Models of Patchy Seabed Habitats Enhance Classification Schemes?

      Predefined classification schemes and fixed geographic scales are often used to simplify and cost-effectively map the spatial complexity of nature. These simplifications can however limit the usefulness of the mapping effort for users who need information across a different range of thematic and spatial resolutions. We demonstrate how substrate and biological information from point samples and photos, combined with continuous multibeam data, can be modeled to predictively map percentage cover conforming with multiple existing classification schemes (i.e., HELCOM HUB; Natura 2000), while also providing high-resolution (5 m) maps of individual substrate and biological components across a 1344 km2 offshore bank in the Baltic Sea. Data for substrate and epibenthic organisms were obtained from high-resolution photo mosaics, sediment grab samples, legacy data and expert annotations. Environmental variables included pixel and object based metrics at multiple scales (0.5 m–2 km), which improved the accuracy of models. We found that using Boosted Regression Trees (BRTs) to predict continuous models of substrate and biological components provided additional detail for each component without losing accuracy in the classified maps, compared with a thematic model. Results demonstrate the sensitivity of habitat maps to the effects of spatial and thematic resolution and the importance of high-resolution maps to management applications.

    • Geosciences, Vol. 9, Pages 236: Insight into Heterogeneous Calcite Cementation of Turbidite Channel-Fills from UAV Photogrammetry

      Diagenesis is a key controlling factor on sandstone porosity and permeability. Understanding type, paragenetic sequence and spatial patterns of cements is thus important for assessing sandstone hydrocarbon reservoir properties. In this study Unmanned Aerial Vehicle (UAV) photogrammetry is used to evaluate the shape and spatial distribution of calcite concretions developed within the sand-prone fill of a turbidite channel. The studied channel-fill is entrenched into hemipelagic marlstones and include a lower conglomeratic sandstone loaded with marlstone rip-ups and an upper fill featuring a range of turbidite bed types, which, up-section and off the channel axis, are progressively finer grained and less amalgamated. Concretion shape analysis highlighted a continuum of equant to oblate shapes with flat-lying major axes and a cumulative volume fraction of ca. 22%. Equant to sub-equant concretions are ubiquitous and occur at different heights within beds, often developing around marlstone rip-ups. Conversely, elongated concretions are either strata-bound concretions or completely cemented beds which become volumetrically dominant up section and off the channel axis. The interparticle pore-space of concretions represents on average ca. 22% and is tightly filled by poikilotopic and blocky calcite cement precipitated near to maximum burial depth, whereas host sandstones lack calcite cements and show smectite clay cement and an average preserved porosity of ca. 15%. The oxygen and carbon isotopes of calcite cements point to the marlstone as the main source of carbonate ions, suggesting concretions developed during burial by either diffusion from rip-ups and mud caps or recrystallization of, matrix micrite. Results suggest that the process by which the carbonate-rich component was eroded from the substrate and trapped within the channel-fill is a key control on spatial distribution of calcite concretions, likely to reflect on spatial variability of reservoir properties.

    • Geosciences, Vol. 9, Pages 235: New Feature Classes for Acoustic Habitat Mapping—A Multibeam Echosounder Point Cloud Analysis for Mapping Submerged Aquatic Vegetation (SAV)

      A new method for multibeam echosounder (MBES) data analysis is presented with the aim of improving habitat mapping, especially when considering submerged aquatic vegetation (SAV). MBES data were acquired with 400 kHz in 1–8 m water depth with a spatial resolution in the decimeter scale. The survey area was known to be populated with the seagrass Zostera marina and the bathymetric soundings were highly influenced by this habitat. The depth values often coincide with the canopy of the seagrass. Instead of classifying the data with a digital terrain model and the given derivatives, we derive predictive features from the native point cloud of the MBES soundings in a similar way to terrestrial LiDAR data analysis. We calculated the eigenvalues to derive nine characteristic features, which include linearity, planarity, and sphericity. The features were calculated for each sounding within a cylindrical neighborhood of 0.5 m radius and holding 88 neighboring soundings, on average, during our survey. The occurrence of seagrass was ground-truthed by divers and aerial photography. A data model was constructed and we applied a random forest machine learning supervised classification to predict between the two cases of “seafloor” and “vegetation”. Prediction by linearity, planarity, and sphericity resulted in 88.5% prediction accuracy. After constructing the higher-order eigenvalue derivatives and having the nine features available, the model resulted in 96% prediction accuracy. This study outlines for the first time that valuable feature classes can be derived from MBES point clouds—an approach that could substantially improve bathymetric measurements and habitat mapping.

    • Time-lapse monitoring of root water uptake using electrical resistivity tomography and Mise-à-la-Masse: a vineyard infiltration experiment

      Time-lapse monitoring of root water uptake using electrical resistivity tomography and Mise-à-la-Masse: a vineyard infiltration experiment Benjamin Mary, Luca Peruzzo, Jacopo Boaga, Nicola Cenni, Myriam Schmutz, Yuxin Wu, Susan S. Hubbard, and Giorgio Cassiani SOIL Discuss., https//doi.org/10.5194/soil-2019-28,2019 Manuscript under review for SOIL (discussion: open, 0 comments) The use of non-invasive geophysical imaging of root system processes is of increasing interest to study soil-plant interactions. The experiment focused on the behaviour of grapevine plants during a controlled infiltration experiment. The combination of the Mise-à-la-masse (MALM) method, a variation of the classical electrical tomography map (ERT), for which the current is transmitted directly into the stem, holds the promise of being able to image root distribution.

    • Revisiting the relationship between soil moisture and N2O production pathways by measuring 15N2O isotopomers

      Revisiting the relationship between soil moisture and N2O production pathways by measuring 15N2O isotopomers Kate A. Congreves, Trang Phan, and Richard E. Farrell SOIL Discuss., https//doi.org/10.5194/soil-2019-27,2019 Manuscript under review for SOIL (discussion: open, 0 comments) There are surprising gaps in the precise quantification of pathways that produce nitrous oxide, a potent greenhouse gas, as influenced by soil moisture. Here, we revisit a classic study, but use isotopomers as a powerful approach to determine the source pathways of nitrous oxide as regulated by soil moisture. Our results support earlier research, but we contribute scientific advancements by providing models that enable quantifying source partitioning rather than just inferencing.

    • Development of a harmonized soil profile analytical database for Europe: A resource for supporting regional soil management

      Development of a harmonized soil profile analytical database for Europe: A resource for supporting regional soil management Jeppe Aagaard Kristensen, Thomas Balstrøm, Robert J. A. Jones, Arwyn Jones, Luca Montanarella, Panos Panagos, and Henrik Breuning-Madsen SOIL Discuss., https//doi.org/10.5194/soil-2019-18,2019 Manuscript under review for SOIL (discussion: open, 1 comment) In a world of increasing pressure on our environment, large scale knowledge about our soil resources is highly demanded. We show how 5 decades of collaboration between EU member states has resulted in a full-covered Soil Profile Analytical Database for Europe (SPADE) with soil data provided by soil experts from each country. We show how this dataset can be applied to estimate SOC-stocks in Europe, and suggest further improvement to this critical support tool for continental scale policies.

    • Changes in soil properties in a low-quality broadleaf mixed forest after cutting strip reforms in a 9-year period in Northeastern China

      Changes in soil properties in a low-quality broadleaf mixed forest after cutting strip reforms in a 9-year period in Northeastern China Huiwen Guan, Xibin Dong, Tian Zhang, Yuan Meng, Jiafu Ruan, and Zhiyong Wang SOIL Discuss., https//doi.org/10.5194/soil-2019-10,2019 Manuscript under review for SOIL (discussion: open, 0 comments) The results show that most soil physical properties were damaged by cutting within 3 years and can be restored after 6 years. Over the 9 years, soil physical properties displayed some differences across cutting strip widths, while chemical properties did not display any differences. In view of the current research years, the soil quality could not be restored in the 18-m harvesting zone within nine years. The cutting width of 10 m is more obvious than that of other transformation widths.

    • Base cations in the soil bank. Non-exchangeable pools may sustain centuries of net loss to forestry and leaching

      Base cations in the soil bank. Non-exchangeable pools may sustain centuries of net loss to forestry and leaching Nicholas P. Rosenstock, Johan Stendahl, Gregory van der Heijden, Lars Lundin, Eric McGivney, Kevin Bishop, and Stefan Löfgren SOIL Discuss., https//doi.org/10.5194/soil-2019-5,2019 Manuscript under review for SOIL (discussion: open, 1 comment) Biofuel harvests from forests involve large removals of available nutrients, necessitating accurate measurements of soil nutrient stocks. We found that dilute hydrochloric acid extractions from soils released far more Ca, Na and K than classical salt-extracted exchangeable nutrient pools. The size of these acid-extractable pools may indicate that forest ecosystems could sustain greater biomass extractions of Ca, Mg, and K, than are predicted from salt-extracted exchangeable base cation pools.