Growing Poplar in Acid Soils: Biomass Yield and Ash Behavior

Atlantic areas of southern Europe have low water restrictions but are also characterized by acid soils with low intrinsic fertility, so the selection of clones that have adapted to these characteristics is essential. In this study, biomass yield data for eight poplar clones established in two trials were evaluated after the first rotation. Both sites were representative of acid soils that had previously been used for agriculture and had low levels of alkali and alkaline earth elements. The first trial was used to determine which clones performed the best in terms of biomass and stem size, testing two Populus × euramericana (Dode) Guinier (I-214 and AF2), two P. × interamericana Van Brokehuizen × P. nigra L. (Monviso, AF6), three P. × interamericana (Unal, Beaupre and Raspalje), and one P. trichocarpa Torr & A. Gray (Trichobel) clone. The second trial explored the possibility of simultaneously growing biomass and timber, specifically considering the Raspalje and Trichobel balsam poplar clones. To complete a previous study on energy properties, nine biomass samples were obtained from each of the eight clones to evaluate the composition and behavior of the ash generated during combustion, particularly the sintering risk. Several indices of sintering risk were explored and compared with the actual sintering using the BioSlag test. The results show large differences in biomass yield between clones, with the balsam poplar derived clones (both hybrid or pure Populus trichocarpa) performing the best. Growth results for stems planted for wood and the cuttings planted in between these stems show that a mixed biomass–timber arrangement provides good results, at least during the first rotation. The relative proportion of oxides in the poplar ash followed the order CaO > K2O > MgO >> P2O5 >> SiO2 > Al2O3 > Na2O > Fe2O5 >> TiO2. Significant differences between clones were found for K2O and MgO. Risk indices showed moderate levels of sintering derived from alkali elements, with significant differences between clones. The actual slagging and the hardness of the slag particles were very low thus, denoting good ash behavior during combustion, particularly for the clones selected for biomass yield. No significant covariate effect of basal diameter was found for any of the analyzed variables. We conclude that growing site-undemanding poplar clones in acid soils can yield both reasonable levels of biomass yield and good quality chips for combustion in domestic thermal systemThis research was financially supported by project RTA2017-00015-C02-02, Spanish Ministry of Economy and CompetitivityS

Multi feature-rich synthetic colour to improve human visual perception of point clouds

Although point features have shown their usefulness in classification with Machine Learning, point cloud visualization enhancement methods focus mainly on lighting. The visualization of point features helps to improve the perception of the 3D environment. This paper proposes Multi Feature-Rich Synthetic Colour (MFRSC) as an alternative non-photorealistic colour approach of natural-coloured point clouds. The method is based on the selection of nine features (reflectance, return number, inclination, depth, height, point density, linearity, planarity, and scattering) associated with five human perception descriptors (edges, texture, shape, size, depth, orientation). The features are reduced to fit the RGB display channels. All feature permutations are analysed according to colour distance with the natural-coloured point cloud and Image Quality Assessment. As a result, the selected feature permutations allow a clear visualization of the scene's rendering objects, highlighting edges, planes, and volumetric objects. MFRSC effectively replaces natural colour, even with less distorted visualization according to BRISQUE, NIQUE and PIQE. In addition, the assignment of features in RGB channels enables the use of MFRSC in software that does not support colorization based on point attributes (most commercially available software). MFRSC can be combined with other non-photorealistic techniques such as Eye-Dome Lighting or Ambient Occlusion.Xunta de Galicia | Ref. ED481B-2019-061Xunta de Galicia | Ref. ED431F 2022/08Agencia Estatal de Investigación | Ref. PID2019-105221RB-C43Universidade de Vigo/CISU

Modelling and evaluation of land use changes through satellite images in a multifunctional catchment: social, economic and environmental implications

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGFloods are recurrent phenomena with significant environmental and socio-economic impacts. The risk of flooding increases when land use changes. The objective of this research is to detect land cover changes via Sentinel-2 images in the Umia Basin (Galicia, NW Spain) in 2016–2021 and to analyse the associated flood risk. This study focuses on how forest use and nature-based solutions (NBS) can reduce the risk and hazard of flooding in cities and crops in the high-risk area. A flood simulation was performed with the land use obtained from Sentinel-2 (Observed) and three more simulations were performed changing the location of afforestation and NBS, i.e. “S-Upstream”, “S-Downstream” and “S-Total”. Finally, the environmental, economic and social impacts of the scenarios designed and estimated are analysed and discussed. Land cover change was successfully monitored with Sentinel-2 imagery. The catchment area showed noteworthy changes in land use, most notably for the category of trees, which covered 6700 ha in 2016 and 10,911 ha in 2021. However riparian vegetation decreased by almost 11%. For the flood hazard simulations, an average reduction in peak discharge was obtained for all three scenarios (9.3% for S-Up; 8.6% for S-Down and 13% for S-Total). From the economic perspective, all three scenarios show a positive net present value for the period studied. However, S-Down is the scenario with the lowest benefits (€15,476,487), while S-Up and S-Total show better values at €29,580,643 and €65,158,130 respectively. However, investment cost is much higher for the S-Total scenario, and upstream actions affect the whole catchment, so S-Up is the best decision. This study concludes that the information provided by satellites is a large-scale analysis tool for small heterogeneous plots that facilitates the comprehensive analysis of a territory. This information can be incorporated into flood analysis models, facilitating simulation through the use of NBS. It has been proven that the use of reforestation upstream only is almost as beneficial as reforestation in the entire catchment and is economically more viable. This confirms that the methodology used reduces flood hazard, despite the territorial complexity, facilitating decision making on the use of NBS.Universidade de Vig

Monitoring and mapping of intertidal macroalgae using low-cost geospatial automated techniques

The global extent of macroalgae is declining with important consequences on marine biodiversity and ecosystem processes. Tracking the status and trends of macroalgal cover is, therefore, an emerging priority for ocean and coastal management. A remote sensing technique combining UAVs surveys with in situ data acquisition was developed to map intertidal macroalgae from rocky shores in a marine protected area, the Atlantic Islands of Galicia National Park (Illas Cíes, NW Spain). The classifcation by groups (brown and green macroalgae) achieved a good precision. A more precise classifcation would be achieved by focusing on those spectral bands where the highest diferences between species appeared.Peer Reviewe

Influence of ashes in the use of forest biomass as source of energy

One of the main challenges using biofuels, such as pellets or wood chips in domestic boilers, is the slagging and fouling risks associated to the process, which could damage the boiler and limit its efficiency. The prediction of sintering and slagging in biomass combustion is essential to establish biofuel quality standards, and minimize their harmful effects. In this work, we analysed the chemical composition of 40 woodchips samples from different genera and origins in order to predict slagging. We studied two indexes of deposition (%B and the NaK/B) in order to limit sintering of biomass ashes. In addition, a new threshold classification was proposed for ratio-slag viscosity index. These indexes were validated with two different tests: a qualitative test, and a quantitative test (Bioslag). Our results showed that the species chosen did not have an impact in slagging and sintering. However, biomass with high concentrations of SiO2 and tree bark showed high risk of slagging. On the other hand, high CaO concentrations showed a low slagging risk. The results obtained from the validation tests showed similar results to the ones obtained from the indexes. It can be concluded that the %B and NaK/B indexes show good potential and should be considered as tools for predicting slagging in woody and herbaceous biomass

GPR application on geothermal studies: the case study of the thermal baths of San Xusto (Pontevedra, Spain)

Geophysical studies are frequently used on the geothermal field to define and characterize deep structures. However, shallow investigations are also needed for understanding the origin and local potential structures of a promising geothermal site. In this research, it is intended to present a review of the possibilities of the application of ground-penetrating radar (GPR) on the study of geothermal resources and how this geophysical technique can contribute to improving the energy use of these thermal resources. For this, the specific case of application to the investigation of the thermal baths of San Xusto (Pontevedra, Spain) is included in this work, whose interest for the region makes it necessary to perform an in-depth analysis of the original thermal structure. A GPR survey with frequency antennas of 200 and 500 MHz was conducted. Additionally, chemical analyses were performed to characterize the thermal water in the San Xusto site. As a result, a hot spring was detected by identifying reverberation phenomena in GPR imaging due to the presence of metal compounds and silica. Locating the origin of the thermal springs could allow for a more efficient use of the thermal resources as well as the hydrothermal possibilities of the area.Xunta de Galicia | Ref. ED431F 2021/08Ministerio de Ciencia e Innovación | Ref. RYC2019-026604-

INFORME CIENTÍFICO – TÉCNICO de la Campaña SUBVENT1

Memoria del Informe Cintífico-Técnico de la campaña oceanográfica SUBVENT-1.Anexos de operatividad y de las distintas técnicas utilizados a lo largo de la misma.La campaña SUBVENT1-0913 se ha realizado a lo largo del talud inferior del margen continental de las Islas Canarias, área que también es conocida en la literatura como Cuenca Canaria. Esta zona se caracteriza por la presencia de una serie de estructuras geológicas recientes, así se encuentran la parte distal de los depósitos de debris procedentes de las avalanchas volcánicas generadas desde las Islas Canarias, a favor de la pendiente y probablemente en relación con episodios eruptivos. En la parte meridional se encuentra además un conjunto de montes submarinos, de diversa entidad, de origen volcánico y, en general, aparece todo un conjunto de montículos con desniveles comprendidos entre 30 y 300 m que han constituido el principal objetivo de esta campaña. Así mismo, en este sector existen numerosos escarpes lineales de orientación subparalela a la del propio talud a los que se encuentran asociados en ocasiones los citados montículos. La adquisición de nuevos datos geofísicos y el muestreo llevado a cabo durante la campaña permitirá conocer mejor el origen de estos montículos y el proceso de emisión que los ha generado. Por otro lado, el conocimiento de las relaciones entre los sedimentos de debris y hemipelágicos junto con los asociados a las posibles emisiones de la zona permitirá conocer no sólo la evolución sedimentaria de este margen, sino establecer los episodios de emisión que generaron los montículos y conocer sus patrones de crecimiento. Así mismo, se podrá evaluar la tasa de sedimentación de la zona y el papel de la masa de agua de fondo antártica (AABW) en esta evolución.The SUBVENT1-0913 cruise has been carried out along the lower slope of the continental margin of the Canary Islands. This area is characterized by the presence of several recent geological structures. Among these are the distal parts of the volcano-clastics debris deposits originated by volcanic avalanches of the Canary Islands, transported by gravity along the slope and probably related in origin to eruptive episodes. In the southern part, numerous and different reliefs (seamounts, hills or mounds) of volcanic origin occur. The most frequents features display heights between 30 and 300 m and they have constituted one of the main aims of this survey. Moreover, in this sector there are several subparallel linear scarps with similar directions to the slope trend that could be associated with the aforementioned mounds. The acquisition of new geophysical data and samples during this campaign will allow a better understanding of the origin of these mounds and the emission processes that have generated them. On the other hand, the knowledge of the relationships between debris and hemipelagic sediments together with those associated with possible venting processes in the area, will reveal not only the sedimentary evolution of this margin, but also to establish emission episodes generating mounds and to know their growth patterns. Furthermore, it would be possible to evaluate the sedimentation rate in the area and the role played by the Antarctic Bottom Water (AABW) mass on this process.Plan Nacional de I+D, Ministerio de Economía y Competitividad. Investigación fundamental no Orientada. Proyecto de Investigación Coordinado SUBVENT “Emisiones submarinas de fluidos en los márgenes continentales de las Islas Canarias y del Golfo de Cádiz: Análisis comparativo de las construcciones asociadas” (CGL2012‐39524‐C02). Acción Complementaria EXARCAN “Trabajos científico-técnicos para la preparación, presentación y defensa de las propuestas de España ante Naciones Unidas para la Extensión de la Plataforma Continental de las Islas Canarias y Galicia” (CTM2010-09496-E)

Scientific and Technical Report of the DRAGO 0511 Oceanographic Cruise. Extension of the Spanish Continental Shelf west off Canary Island

Informe científico de la campaña y de los resultados preliminaresLa campaña DRAGO 0511 forma parte de los trabajos para la extensión de la plataforma continental española al oeste de las islas Canarias conforme a la Convención de Naciones Unidas sobre Derecho del Mar (CONVEMAR). Han participado un total de 19 científicos y técnicos, 4 investigadores del Instituto Español de Oceanografía (IEO) y 4 investigadores del Instituto Geológico y Minero de España (IGME) del Ministerio de Ciencia e Innovación, 2 investigadores de TRAGSA (para la Secretaría General del Mar) del Ministerio de Medio Ambiente, Medio Rural y Marino, y 6 hidrógrafos del Instituto Hidrográfico de la Marina (IHM) del Ministerio de Defensa, así como 5 estudiantes (2 de grado y 3 de postgrado) de la Facultad de Ciencias del Mar y Ambientales de la Universidad de Cádiz, y de la Facultad de Ciencias Geológicas (Titulación de Ingeniería Geológica) de la Universidad Complutense. El objetivo de esta campaña es la adquisición de los datos científicos necesarios para preparar la propuesta de ampliación de la plataforma continental española más allá de las 200 millas marinas del área situada al oeste de las Islas Canarias, conforme al artículo 76 de CONVEMAR. La información que se ha obtenido es fundamentalmente de batimetría multihaz y monohaz, perfiles de la velocidad del sonido, perfiles sísmicos de alta resolución, y muestreo de fondos principalmente mediante dragas de roca. Estos datos permitirán definir desde un punto de vista morfográfico, morfosedimentario y geológico, la región de la base del talud, así como llevar a cabo la localización de los posibles pies de talud (FOS) en esta región,y demostrar la estrecha relación existente entre la zona estudiada y el archipiélago de las Islas Canarias. En este sentido se han estudiado de forma preferente un conjunto de montes submarinos presentes al suroeste de las islas Canarias cuya génesis, de origen magmático, se debe encontrar en los mismos procesos de “punto caliente” que probablemente han debido generar los edificios volcánicos que constituyen las propias islas Canarias. Por otro lado, se ha localizado la presencia de grandes cuerpos sedimentarios constituidos por materiales procedentes de estos montes submarinos y generados por movimientos en masa de tipo gravitacional a favor de la pendiente del talud continental. La presencia tanto de estos montes submarinos, como de las grandes masas de sedimentos gravitacionales y, además la localización de escarpes en el talud, serán puntos clave de gran interés en esta región, siendo argumentos científicos válidos para demostrar la prolongación natural del territorio emergido del archipiélago canario así como para localizar los puntos del pie del talud continental. Durante la campaña DRAGO 0511 se han adquirido un total de 10895.4 km de registros con sonda multihaz EM302, sonda monohaz EA 600 y sonda paramétrica TOPAS PS 18. De dichas líneas, 9647.3 km se han realizado en las dos zonas de trabajo planificadas, 5603.2 km en la zona A y 4044.3 km en la zona B. En la zona A se ha cubierto un área total de 19996 km2 mientras que en la zona B la extensión ha sido de 13545 km2. En total se ha cubierto una extensión de 17795 km2 en el área de posible ampliación de la plataforma continental española. Por otra parte, cabe señalar que además 16471 km2 de líneas se han realizado dentro de la ZEE española del archipiélago canario, que se utilizarán, en algún caso, para demostrar la continuidad de estos cuerpos sedimentarios con las islas Canarias, y más adelante para la cartografía de este sector de la ZEE española. El resto de registros, 1151.5 km. corresponden a los tránsitos. En el total del tiempo de la campaña DRAGO 0511, un 70.5 % se ha trabajado sobre las zonas planificadas A y B localizadas sobre las áreas de ampliación de la plataforma continental española o sobre puntos concretos de la ZEE española que pueden ser utilizados para establecer los FOS, un 16.7 % en tránsitos sobre la ZEE española de las islas Canarias y un 7.1% de recalada en los puertos de Santa Cruz de Tenerife y de La Estaca de la Iila de El Hierro. Los datos obtenidos en la campaña DRAGO 0511 serán usados para elaborar la presentación del trazado del límite exterior de la plataforma continental de España más allá de las 200 millas marinas en el polígono del archipiélago de las islas Canarias conforme a la parte VI y el anexo II de CONVEMAR. Dicha presentación de datos e información científica se deberá realizar ante la Comisión de límites de la plataforma continental de la Organización de las Naciones Unidas en Nueva York, de conformidad con la CONVEMAR y con las directrices científico-técnicas de dicha Comisión, con anterioridad al 9 de mayo del año 2014.Ministerio de Asuntos Exteriores y Cooperación (MAEC), Instituto Español de Oceanografía (IEO) e Instituto Geológico y Minero de España (IGME) ambos del Ministerio de Investigación, Ciencia e Industria (MICINN), Instituo Hidrográfico de la Marina (IHM) del Ministerio de Defensa (MDEF) y Secretaria General del Mar del Ministerio de Medio Ambiente, Medio Rural y Marino (MARM). Acción Complementaria del Plan Nacional de I+D+i CTM2010-09496-

Identificación de riesgos geoambientales y su valoración en la zona de hundimiento del buque Prestige

Potential geological hazard assessment has been carried out in the area where the Prestige vessel was sunk using a broad database that comprises: multibeam, high and ultra-high resolution seismic profiles, gravity cores, onland seismicity stations and Ocean Bottom Seismometers (OBS). The main results of this study indicate that among the geologic factors that can be considered as potential hazards, four main categories can be differentiated based on their origin: morphologic, sedimentary, tectonic, and seismicity. Hazards of morphologic origin include steep gradients; the morphologic features suggest the occurrence of mass-wasting instabilities. Hazards of sedimentary origin also includes the occurrence of slope instability processes in form of single slides and a great variety of erosive and depositional gravity flows (debris and turbidity flows). Hazards of tectonic and seismic origin are important because the sinking area straddles the Calida Bank which is a structural seamount with a moderate tectonic activity that results in a latent seismicity of low to moderate magnitude. The interaction of these factors leads to consider to the risk as medium, and the degree of exposure of the bow and stern as high. Several general and specific recommendations are made in order to increase the geological and geophysics knowledgement in the Prestige sinking area and Spanish continental margins and deep sea areas. These recommendations also should be used to elaborate the options for reducing the hazard and loss