Invertebrate and microbial marine communities associated with mammal bones are interesting and poorly understood habitats, mainly known from studies on deep‐water whale remains. In order to characterize these communities in the shallow‐water Mediterranean, we present here the results of a pioneering experiment using mammal bones. Minke whale, pig and cow bones were experimentally deployed on three different background communities: rocky substrate, soft‐bottom and a Posidonia oceanica meadow. Bones were deployed for a year at about 20 m depth and collected every 3 months, and the invertebrate fauna colonizing the bones was identified to the lowest possible taxonomic level. As expected, mammal bones showed remarkable differences when compared with background communities. Within bones, four different clusters could be identified, primarily on the basis of the polychaete fauna, the most abundant and diverse group in the survey. Clusters A1–A3 corresponded to high to moderately altered successional stages composed by a fauna closer to that of anthropogenically enriched shallow‐water environments. These clusters were characterized by the occurrence of the opportunist polychaetes Ophryotrocha puerilis, Neanthescaudata (Cluster A1), Protodorvillea kefersteini (Cluster A2) and Ophryotrocha alborana (Cluster A3). Cluster B was characterized by the presence of the polychaete Oxydromus pallidus together with typical invertebrate background fauna, which suggests that this community, after a year of deployment, was closer to that found in natural conditions. As opposed to similar shallow‐water studies in other geographic areas, no occurrence of the polychaete Osedax (commonly known as bone‐eating worms) was reported from our experiments. Apart from the study on the invertebrate communities, insights about the population dynamics of three of the most abundant species (O. puerilis, O. alborana, N. caudata) are given as well as remarks on a hypothetical trophic network based on fecal pellet analysis. 相似文献
Pulsating structures recorded at 237 MHz that are associated to decimetric continuum enhancement during the September 9, 2001 solar radio burst are described. We analyzed the radiopolarimetric data recorded at the Trieste Solar Radio System (INAF—Trieste Astronomical Observatory—Basovizza Observing Station) with very high time resolution (1 ms) at metric frequencies. Two different types of pulsations that occur in about 4 minutes at the same frequency are described. The possible mechanisms are analyzed and some parameters of the associated magnetic structure are estimated. 相似文献
The influence of sea surface temperature (SST) of the ocean on seasonal rainfall in Northwestern Iberian Peninsula is studied for the period 1951–2006. Seasonal correlations were calculated for all seasons and different lags applied on SST. A test for field-significance considering the properties of finiteness and interdependence of the spatial grid was applied to avoid correlations by chance. The most significant and repetitive correlation is found between SST over Equatorial Pacific and spring rainfall. The correlation is maintained for different lags, and the common area that satisfies the criteria for statistical field significance is coincident with ENSO area. A forecast scheme is developed to predict spring rainfall anomalies based in SST over ENSO area in precedent seasons. An analysis of principal components was also carried out to obtain the main modes of the Pacific Ocean and their influence on spring rainfall in NWIP. This study concludes that for the period 1951–2006 the negative phase of ENSO, “La Niña”, almost always announces dry springs in NW Iberian Peninsula. However, the positive phase of ENSO, “El Niño”, does not anticipate the appearance of wet springs. 相似文献
Investigation of deposits for traditional extraction activities (metals and coal) has generally been based on determining grade, or content, of the required material. In order to apply the grade concept to an ornamental rock such as slate, it is first necessary to define the variables that determine both the geotechnical recovery rate for the rock mass — which conditions the size of the extracted blocks – and the aesthetic features of the slate — which define the quality of the slabs as potential roofing material.
For this research, geotechnical and aesthetic data for a slate deposit were collected from 16 continuous core borehole samples. A fuzzy expert system was then developed using this data, defining the rock mass recovery rate and slab quality in accordance with the criteria of a slate expert, producing as a final output a zonation of the deposit in terms of top quality slate, medium quality slate or waste.
A mathematical model based on fuzzy logic was chosen due to the fact that the boundaries between different quality groups in a deposit are not clearly distinguished. Moreover, quality also depends on a company's infrastructures for transformation of the blocks, and also on its commercial strategies. 相似文献
Summary Petrographic, geochemical and isotopic data are reported for the mafic microgranular enclaves occurring in a calc-alkaline Oligocene pluton outcropping near Xanthi town in northern Greece. The intrusion is composed of dominant granodiorites with minor tonalites and quartz diorites. Mafic enclaves occur in large swarms concentrated near the margins of the pluton. They have fine-grained porphyritic textures and contain the same minerals as their granodioritic and tonalitic host rocks (Pl, Qtz, Bt, Hb1, Kfs ± Ap, Zrn, Mt, Spn) but in totally different modal proportions. Chemical compositions range from mafic to intermediate and are characterized by higher abundance of Na2O) and lower contents of CaO and Sr with respect to an average basaltic magma with a similar SiO2 content. The initial Sr isotopic ratios, ranging from 0.7061 to 0.7063, are similar to those of the enclosing rocks (0.7062-0.7063). Field evidence, as well as petrographic and geochemical data, suggests that the analyzed enclaves derived from disruption of synplutonic intrusions of cogenetic mafic magma. The Xanthi pluton could represent ascent of a zoned magma body, with a silicic cap (granodiorite, tonalite, quartz diorite) having intruded first followed by the deeper more mafic levels as syn-intrusive dikes.
Mafische mikrogranulare Enklaven aus dem Xanthi Pluton, Nord-Griechenland: Ein Beispiel von mafisch-felsischer Magma-Wechselwirkung
Zusammenfassung Petrographische, geochemische und Isotopen-Daten für mafische mikrogranulare Enklaven in einem kalk-alkalischen oligozänen Pluton, der in der Nähe der Stadt Xanthi in Nord-Griechenland aufgeschlossen ist, werden präsentiert. Die Intrusion besteht hauptsächlich aus Granodioriten mit untergeordneten Tonaliten und QuarzDioriten. Mafische Enklaven kommen in großen Schwärmen, besonders an den Rändern des Plutons vor. Sie zeigen feinkörnige prophyritische Texturen und enthalten diesselben Minerale wie ihre granodioritischen und tonalitischen Wirtsgesteine (P1, Qtz, Bt, Hb1, Kfs ± Zrn, Mt, Spn), aber in vollkommen verschiedenen modalen Verhältnissen. Chemische Zusammensetzungen schwanken von mafisch bis intermediär und werden durch höhere Gehalte an Na2O und niedriger Gehalte von CaO und Sr, verglichen mit durchschnittlichem Basaltmagma mit ähnlichem SiO2-Gehalt, gekennzeichnet. Die Strontium-Initiale schwanken von 0,7061 bis 0,7063, und sind denen der umgebenden Gesteine (0,7062-0,7063) ähnlich. Geländebefunde, wie auch petrographische und chemische Daten, zeigen, daß die analysierten Enklaven auf das Aufbrechen von synplutonischen Intrusionen cogenetischen mafischen Magmas zurückgehen. Der XanthiPluton könnte dem Aufstieg eines zonierten Magmenkörpers zuzuordnen sein, mit einem Si-reichen Dach (Granodiorite, Tonalite, Quarzdiorite), das zuerst intrudiert ist, gefolgt von den tiefer angesiedelten, mehr mafischen Gesteinen als syn-intrusive G:ange.