Detection of Tephra Layers in Antarctic Sediment Cores with Hyperspectral Imaging

Tephrochronology uses recognizable volcanic ash layers (from airborne pyroclastic deposits, or tephras) in geological strata to set unique time references for paleoenvironmental events across wide geographic areas. This involves the detection of tephra layers which sometimes are not evident to the naked eye, including the so-called cryptotephras. Tests that are expensive, time-consuming, and/or destructive are often required. Destructive testing for tephra layers of cores from difficult regions, such as Antarctica, which are useful sources of other kinds of information beyond tephras, is always undesirable. Here we propose hyperspectral imaging of cores, Self-Organizing Map (SOM) clustering of the preprocessed spectral signatures, and spatial analysis of the classified images as a convenient, fast, non-destructive method for tephra detection. We test the method in five sediment cores from three Antarctic lakes, and show its potential for detection of tephras and cryptotephras.info:eu-repo/semantics/publishedVersio

Revista de Vertebrados de la Estación Biológica de Doñana

Página 298 con error de impresiónEstudio cariológico en dos especies de Serránidos del Mediterráneo (Peces: PerciformesRelaciones morfométricas de Atherina boyeri Risso (Pisces: Atherinidae) de la laguna de Zoñar (Córdoba, España)Contribución al conocimiento de la biometríay osteología de Barbus barbus bocagei, Steindachner, 1866 (Pisces: CyprinidaeLa actividad de la salamandra, Salamandra salamandra (L.), en Galicia.Estudios sobre el sapo corredor (Bufo calamita) en el Sur de España.1. BiometríaEstudios sobre el sapo corredor (Bufo calamita) en el Sur de España. II. AlimentaciónBiología de la reproducción de Rana iberica Boulenger 1879 en zonas simpátridas con Rana temporaria Linneo, 1758Nuevos datos sobre la distribución geográfica de Lacerta monticola cantabrica Mertens, 1929. (Sauria, lacertidae).Datos sobre Lacerta monticola Boulenger, 1905 (Saurio: lacertidae)en el oeste del Sistema Central.Nueva especie de Anolis (lacertilia, Iguanidae) para CubaEtograma cuantificado del cortejo en Falco naumannOntogénesis del comportamiento predador en Falco naumanniContaminación xenobiótica del Parque Nacional de Doñana. 1. Residuos de insecticidas organoclorados, bifenilos policlorados y mercurio en anseriformes y gruiformesReproducción del críalo (Clamator glandarius) en Sierra Morena CentraNidificación de Picus viridis en taludes de arcilla en Ramblas de Guadix (Granada)Comportamiento del calamón Porphyrio porphyrio (Linnaeus, 1758) en Doñana, Marismas del GuadalquiviBiología y ecología de la malvasía (Oxyura leucocephala) en Andalucía.On the differential diet of Carnivora in islands:a method for analysing it and a particular case.Notas sobre la distribución pasada y actual del meloncillo Herpestes ichneumon (L.) en la Península IbéricaEstructuración de las interacciones en una camada de lobos (Canís lupus)Nuevos datos sobre la distribución del Cottus gobio L. (pisces, cottidae) en EspañaSobre la alimentación de Callopistes maculatus (Reptilia,teiidaeObservación de Lacerta lepida depredando un nido de Alectoris rufaNueva cita del galápago leproso Mauremys leprosa (Scheigger, 1812) en los pirineosPrimera cita de Psammodromus hispanicus (Fitzinger) para GaliciaSobre la presencia de Gallotia (=Lacerta) atlantica (Peters y Doria, 1882) en Gran CanariaNota sobre las Lacerta monticola Boulenger, 1905 de las zonas del norte de GaliciaPrimeras notas herpetológicas de la provincia de Soria.Datos sobre selección de hábitat y ecología alimenticia del porrón pardo (Aythya nyroca)Probable nueva área de cría del pechiazul (Luscinia svecica cyanecula) en el sistema central. PerisPredación de Falco peregrinus y Falco subbuteo sobre quirópterosResultados de la producción de Oxyura leucocephala en el año 1981 en las lagunas de Zóñar y el rincónAnálisis de la dieta de Tyto alba en un medio árido antropógeno de los alrededores de Almería¿Son Eudocimus ruber y E. albus distintas especies?EL Estornino pinto (Sturnus vulgaris) en Canarias: nueva especie nidifiante en el archipiélagoDatos sobre la alimentación otoñal del cárabo (Strix aluco) en la sierra de CádizObservación primaveral de rapaces y otras aves en el páramo del estado de Mérida (Venezuela).Murciélago hematófago (Desmodus rotundus) parasitando a un chigüire (Hidrochoerus hydrochaeris)Observaciones sobre la reproducción del zacatuche o teporinho Romerolagus diazi (Mammalia: lagomorpha)Estudio electroforético de hemoglobinas y esterasas sanguíneas en Rhinolophus ferrumequinum (Chiroptera: rhinolophidae) y de hemoglobinas en Tadaria taeniotis (chiroptera: molossidae)Peer reviewe

Phytoplankton descrimination from fluorescence spectra using neural networks

Martech 2007 International Workshop on Marine Technology, 15-16 november 2007, Vilanova i la Geltrú, Spain.-- 2 pages, 3 figures, 1 tableThe project VARITEC-SAMPLER (CTM2004-04442-C02-2/MAR) is funded from the Spanish Ministry of Education and SciencePeer reviewe

Analysis of Discrimination Techniques for Low-Cost Narrow-Band Spectrofluorometers

24 pages, 12 figures, 12 tablesThe need for covering large areas in oceanographic measurement campaigns and the general interest in reducing the observational costs open the necessity to develop new strategies towards this objective, fundamental to deal with current and future research projects. In this respect, the development of low-cost instruments becomes a key factor, but optimal signal-processing techniques must be used to balance their measurements with those obtained from accurate but expensive instruments. In this paper, a complete signal-processing chain to process the fluorescence spectra of marine organisms for taxonomic discrimination is proposed. It has been designed to deal with noisy, narrow-band and low-resolution data obtained from low-cost sensors or instruments and to optimize its computational cost, and it consists of four separated blocks that denoise, normalize, transform and classify the samples. For each block, several techniques are tested and compared to find the best combination that optimizes the classification of the samples. The signal processing has been focused on the Chlorophyll-a fluorescence peak, since it presents the highest emission levels and it can be measured with sensors presenting poor sensitivity and signal-to-noise ratios. The whole methodology has been successfully validated by means of the fluorescence spectra emitted by five different cultures. © 2014 by the authors; licensee MDPI, Basel, SwitzerlandThis work was supported by the Spanish National Research Council (CSIC) under the project ANERIS (PIF-015-1), by the Ministerio de Ciencia e Innovación under Mestral Project CTM2011-30489-C02-01, and by the European Commission under Citclops Project FP7-ENV-308469. Ismael F. Aymerich is currently funded by the European Regional Development Fund (ERDF) and the Galician Regional Government under agreement for funding the Atlantic Research Center for Information and Communication Technologies (AtlantTIC) and under the project TACTICA. Sergio Pérez was involved in the SICUE program and funded by the Séneca fellowship, given by the Ministerio de Educación, during the development of this projectPeer Reviewe

Low cost hyperspectral device suitable for monitoring sensor networks

Martech 2007 International Workshop on Marine Technology, 15-16 november 2007, Vilanova i la Geltrú, Spain.-- 2 pages, 3 figuresThis research has been supported by the project VARITEC-SAMPLER (CMT2004-0442-C02-2/MAR), funded from the Spanish Ministry of Education and SciencePeer reviewe

A rapid technique for classifying phytoplankton fluorescence spectra based on self-organizing maps

11 pages, 13 figures, 7 tablesFluorescence spectroscopy has been demonstrated to be a powerful tool for characterizing phytoplankton communities in marine environments. Using different fluorescence spectra techniques, it is now possible to discriminate the major phytoplankton groups. However, most of the current techniques are based on fluorescence excitation measurements, which require stimulation at different wavelengths and thus considerable time to obtain the complete spectral profile. This requirement may be an important constraint for several mobile oceanographic platforms, such as vertical profilers or autonomous underwater vehicles, which require rapid-acquisition instruments. This paper presents a novel technique for classifying fluorescence spectra based on self-organizing maps (SOMs), one of the most popular artificial neural network (ANN) methods. The method is able to achieve phytoplankton discrimination using only fluorescence emission spectra (single wavelength excitation), thus reducing the acquisition time. The discrimination capabilities of SOM using excitation and emission spectra are compared. The analysis shows that the SOM has a good performance using excitation spectra, whereas data preprocessing is required in order to obtain similar discrimination capabilities using emission spectra. The final results obtained using emission spectra indicate that the discrimination is properly achieved even between algal groups, such as diatoms and dinoflagellates, which cannot be discriminated with previous methods. We finally point out that although techniques based on excitation spectra can achieve a better taxonomic accuracy, there are some applications that require faster acquisition processes. Acquiring emission spectra is almost instantaneous, and techniques such as SOM can achieve good classification performance using appropriately preprocessed dataThis work was supported by the project ANERIS (PIF-015-1), funded by the Spanish National Research Council (CSIC)Peer reviewe

Potential support vector machines and Self-Organizing Maps for phytoplankton discrimination

Neural Networks (IJCNN), The 2010 International Joint Conference on, 18-23 July 2010Fluorescence spectroscopy is a powerful technique usually used to evaluate phytoplankton marine environments. In this study, a kernel method (Potential Support Vector Machine, P-SVM) is presented, evaluating its capability to achieve phytoplankton classification from its fluorescence spectra. Different phytoplankton species were studied, and their fluorescence spectra were acquired in laboratory. In a previous study working with Self-Organizing Maps (SOM), it was proved with experimental data from laboratory that excitation spectra were more discriminative than emission spectra. It was also shown that using some preprocessing techniques, such as derivative analysis, the classification performance from emission fluorescence data can be improved. The classification results were encouraging to keep working with emission fluorescence, and herein we present a comparison between P-SVM and SOM for this goalPeer reviewe

Planning the installation of the European Multidisciplinary Sea-floor Observatory (EMSO): First approach using geographic information systems (GIS)

The design, installation and maintenance of any submarine cable are difficult tasks necessary done for long-term submarine observatories. Cable installation and maintenance is one of the most expensive parts of a submarine cable system. To reduce costs, computer-based approaches are used for planning the installation and the maintenance of these networks. This contribution wants to briefly describe some basis to take into account in the framework of the European Multidisciplinary Sea-floor Observatory (EMSO). Quality improvements can reduce costs in cable installations. Submarine cable installation quantity is dramatically increasing, and these new tools minimize human error and reduce the added time at sea due to errors, reducing costs at the same timePeer Reviewe

Cable planning for the european multidisciplinary seafloor observatory: open-source GIS software Uused to determine optimal cable deployment of an underwater Observatory Network

The article discusses the use of Geographic Resources Analysis Support System (GRASS) software to analyze the costs of installation and maintenance of the cable system that will eventually be used for the European Multidisciplinary Seafloor Observatory (EMSO). GRASS is a free, open-source GIS capable of handling raster, topological vector, image processing and graphic data. The software has evolved into a powerful software suite with a wide range of applications in many different areas of scientific research. The cost function determines the cumulative cost of moving from one cell to another. Each cell provides information about the cost of traversing it. GRASS can use a special algorithm, called the 'knight's move,' which takes into account cells not immediately adjacent. In a recent CSIC study, the optimal path for the deployment of the cable being used in the GEOSTAR demonstration mission in the Gulf of Cadiz was foundPeer Reviewe

Fast phytoplankton classification from emission fluorescence spectra based on Self-Organizing Maps

OCEANS'08 MTS/IEEE Quebec "Oceans, Poles & Climate: Technological Challenges", 15-18 September 2008, Quebec City, CanadaFluorescence spectroscopy is a powerful technique usually used to evaluate phytoplankton marine environments. In this study, a fast-technique for phytoplankton discrimination is presented based on the Self-Organizing Maps (SOM), evaluating its capability to achieve phytoplankton classification from its emission fluorescence spectra. The aim of this work is to reduce the acquisition time required for some of the existing techniques. Several cultures representing different algae groups were grown under the same conditions and their Emission spectra were measured every day. Finally, SOM analysis combined with derivative analysis was performed obtaining encouraging resultsPeer Reviewe