107 research outputs found
New records of hydropolyps (Cnidaria, Hydrozoa) from South-western Atlantic Ocean
Eight hydroid species found in different sectors of the Argentine continental shelf are analyzed. Descriptions, measurements and illustrations for the new subantarctic records are shown: Opercularella belgicae (Hartlaub, 1904) (Leptomedusae, Campanuliniidae), Campanularia agas (Cornelius, 1982) and Clytia hemisphaerica (Linnaeus, 1767) (Leptomedusae,
Campanulariidae). Filellum antarcticum (Hartlaub, 1904) (Leptomedusae, Lafoidea), Synthecium robustum Nutting, 1904 (Leptomedusae, Syntheciidae) and Eudendrium ramosum (Linnaeus, 1758) (Anthomedusae, Eudendriidae) are first records in the Argentine biogeographical province; whereas Plumularia insignis Allman, 1883 (Leptomedusae, Plumulariidae) and Bougainvillia ramosa (Van Beneden, 1844) (Anthomedusae, Bougainvilliidae) extend
their distributions towards the north of the Argentine continental shelf.
Key words: Cnidaria, Hydropolyps, Distribution, Systematic, Argentine
Association between hydroid species and their substrates from the intertidal zone of Mar del Plata (Argentine)
A Tailored Approach for the Global Gas Flaring Investigation by Means of Daytime Satellite Imagery
Investigating Phases of Thermal Unrest at Ambrym (Vanuatu) Volcano through the Normalized Hot Spot Indices Tool and the Integration with the MIROVA System
First Implementation of a Normalized Hotspot Index on Himawari-8 and GOES-R Data for the Active Volcanoes Monitoring: Results and Future Developments
La fauna asociada a Tubularia crocea (Agassiz, 1862) (anthomedusae; tubulariidae) y la aplicación de un método de cartificación
A systematic list of the organisms found on the polyps of T. crocea is presented. Monthly samples from the coast of Mar del Plata (38°03'S ; 57°31'W) allowed the analysis of the dynamic of the associations, specially with picnogonids, amphipods, annelids and nematodes, which varied in composition and abundance along of year. We present a modification of a mapping model of Marfenin (1980) and its use to present the different stages of the polyps and the localization of the associated organisms.Se presenta un listado sistemático de los organismos hallados sobre los pólipos de T. creocea. Muestras mensuales obtenidas en la costa de Mar del Plata (38°O8'S ; 57°31'W) permitieron el análisis de la dinámica de las asociaciones, especialmente con picnogónidos, anfípodos, anélidos y nemátodos, las cuales variaron en composición y abundancia a través del año. Nosotros presentamos una modificación del modelo de cartificación de Marfenin (1980) y su uso para representar distintos estados de los pólipos y la localización de los organismos asociados
Robust TIR satellite techniques for monitoring earthquake active regions: limits, main achievements and perspectives
In the last few years, Robust Satellite data analysis Techniques (RST) have been proposed which significantly
improved present capabilities to investigate possible relations between TIR signal fluctuations and earthquake
occurrence. This paper, starting from a critical survey of results achieved by applying different RST-based algorithms
to different satellite sensors to approximately ten earthquakes (two of them are discussed here for the first
time) which occurred in three different continents, tries to offer a first assessment of main achievements, residual
limits and perspectives of such studies. Even if it is still not possible to relate (or to exclude) observed anomalous
TIR transients definitely to impending earthquakes, such studies demonstrate at least: a) the strong improvement
of S/N ratio achievable moving from polar to geostationary satellites; b) the further S/N improvement
achievable by using TIR sensors which also offer split-window possibilities; c) the crucial role played by a
space-time persistence test to select TIR anomalies candidate to be associated to impending earthquakes; d) the
possibility of identifying and correctly discarding TIR anomalies related to clouds and to image navigation errors;
e) the scarce importance of spatial resolution of observations which encourages the use of passive MW sensors
which are less affected by atmospheric conditions
Podocoryna tenuis (Hydrozoa) en aguas templadas del Atlántico Sudoccidental: datos adicionales sobre las etapas del ciclo de vida respaldan su sinónimo con Podocoryna humilis
Two species of Hydractiniidae (Hydrozoa) with metagenetic life cycle have been recorded for the temperate region of the southwestern Atlantic Ocean: the medusa stage of Podocoryna tenuis and the polyp stage of P. humilis. Both the adult medusa of P. humilis and the polyp stage of P. tenuis are unknown, but it is possible that they are different stages of the same species, a hypothesis still to be tested. Colonies of P. humilis growing on the southern king crab Lithodes santolla collected at the Atlantic Patagonian coast, and two small medusae released from these hydroid colonies were analyzed. Medusa of P. humilis were kept alive for 3 days and they were morphologically compared with the medusae of P. tenuis sorted out from ~ 2,500 plankton samples along the Atlantic Patagonian coast. The study of these specimens allowed reassessing the taxonomic status of P. humilis and P. tenuis from the southwestern Atlantic Ocean. Polyp and young medusa stages of P. humilis were described, and additional information was recovered to better describe the medusa stage of P. tenuis. New morphologic and biogeographic evidences in order to propose the synonymy between P. tenuis and P. humilis were discussed.Se han registrado dos especies de Hydractiniidae (Hydrozoa) con ciclo de vida metagenético para la región templada del suroeste del Océano Atlántico: la etapa de medusa de Podocoryna tenuis y la etapa de pólipo de P. humilis. Tanto la medusa adulta de P. humilis como el estadio de pólipo de P. tenuis son desconocidos, pero es posible que se trate de diferentes estadios de una misma especie, hipótesis aún por contrastar. Se analizaron colonias de P. humilis que crecían sobre la centolla Lithodes santolla recolectadas en la costa atlántica de la Patagonia, y dos pequeñas medusas liberadas de estas colonias de hidroides. Las medusas de P. humilis se mantuvieron vivas durante 3 días y se compararon morfológicamente con las medusas de P. tenuis seleccionadas de ~ 2.500 muestras de plancton a lo largo de la costa atlántica patagónica. El estudio de estos especímenes nos permitió reevaluar el estado taxonómico de P. humilis y P. tenuis del Océano Atlántico Sudoccidental. Se describen las etapas de pólipo y medusa joven de P. humilis, y se recuperó información adicional para describir mejor la etapa de medusa de P. tenuis. Se discuten las nuevas evidencias morfológicas y biogeográficas para proponer la sinonimia entre P. tenuis y P. humilis
Robust Satellite-Based Identification and Monitoring of Forests Having Undergone Climate-Change-Related Stress
Climate-induced drought events are responsible for forest decline and mortality in different areas of the world. Forest response to drought stress periods may be different, in time and space, depending on vegetation type and local factors. Stress analysis may be carried out by using field methods, but the use of remote sensing may be needed to highlight the effects of climate-change-induced phenomena at a larger spatial and temporal scale. In this context, satellite-based analyses are presented in this work to evaluate the drought effects during the 2000s and the possible climatological forcing over oak forests in Southern Italy. To this aim, two approaches based on the well-known Normalized Difference Vegetation Index (NDVI) were used: one based on NDVI values, averaged over selected decaying and non-decaying forests; another based on the Robust Satellite Techniques (RST). The analysis of the first approach mainly gave us overall information about 1984-2011 rising NDVI trends, despite a general decrease around the 2000s. The second, more refined approach was able to highlight a different drought stress impact over decaying and non-decaying forests. The combined use of the RST-based approach, Landsat satellite data, and Google Earth Engine (GEE) platform allowed us to identify in space domain and monitor over time significant oak forest changes and climate-driven effects (e.g., in 2001) from the local to the Basilicata region scale. By this way, the decaying status of the Gorgoglione forest was highlighted two years before the first visual field evidence (e.g., dryness of apical branches, bark detachment, root rot disease). The RST exportability to different satellite sensors and vegetation types, the availability of suitable satellite data, and the potential of GEE suggest the possibility of long-term monitoring of forest health, from the local to the global scale, to provide useful information to different end-user classes
Earthquake-Related Signals in Central Italy Detected by Hydrogeochemical and Satellite Techniques
Central Apennines are one of the highest seismic risk regions in Italy. A number of energetic events ((Formula presented.) > 5) struck the region during the period 2004–2017, killing several hundreds of people (e.g., 294 casualties associated with the August 24th, 2016, (Formula presented.) 6.0 event of Amatrice). These earthquakes impacted piezometric levels, springs discharges, and groundwater chemistry across a large area, even at distances of dozens of kilometers from the epicenters. Here we present a multidisciplinary dataset based on hydrogeochemical and satellite observations associated with the seismic events that occurred in Central Italy during the period 2004–2017, which combines information derived from the application of groundwater monitoring and satellite techniques. Groundwater monitoring techniques allowed for the detection of hydrogeochemical anomalies in spring and well waters (14 water sampling points in total, with 22 variations larger than (Formula presented.)), while satellite techniques were applied to detect time-space variations in ground thermal emissions. We detected two significant, almost synchronous, anomalies in 2009 and 2016–2017 with both techniques, and we tentatively correlated them to crustal deformation processes. Part of the observed signals were detected before mainshocks, and they appear to be related to aseismic slip or to seismic slip eventually induced by minor fluctuations in seismicity. We argue that the combination of two factors, i.e., the shallow depth of local earthquakes and the concurrent deepening of groundwater circulation paths to several km depth, allow for the recording of variations in the stress field by geofluids released at the surface
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