Frisia S.,University of Newcastle |
Fairchild I.J.,University of Birmingham |
Fohlmeister J.,Heidelberger Akademie der Wissenschaften |
Miorandi R.,Museo Tridentino di Science Naturali |
And 2 more authors.
Geochimica et Cosmochimica Acta | Year: 2011
Diverse interpretations have been made of carbon isotope time series in speleothems, reflecting multiple potential controls. Here we study the dynamics of 13C and 12C cycling in a particularly well-constrained site to improve our understanding of processes affecting speleothem δ13C values. The small, tubular Grotta di Ernesto cave (NE Italy) hosts annually-laminated speleothem archives of climatic and environmental changes. Temperature, air pressure, pCO2, dissolved inorganic carbon (DIC) and their C isotopic compositions were monitored for up to five years in soil water and gas, cave dripwater and cave air. Mass-balance models were constructed for CO2 concentrations and tested against the carbon isotope data. Air advection forces winter pCO2 to drop in the cave air to ca. 500ppm from a summer peak of ca. 1500ppm, with a rate of air exchange between cave and free atmosphere of approximately 0.4days. The process of cave ventilation forces degassing of CO2 from the dripwater, prior to any calcite precipitation onto the stalagmites. This phase of degassing causes kinetic isotope fractionation, i.e. 13C-enrichment of dripwater whose δ13CDIC values are already higher (by about 1‰) than those of soil water due to dissolution of the carbonate rock. A subsequent systematic shift to even higher δ13C values, from -11.5‰ in the cave drips to about -8‰ calculated for the solution film on top of stalagmites, is related to degassing on the stalagmite top and equilibration with the cave air. Mass-balance modelling of C fluxes reveals that a very small percentage of isotopically depleted cave air CO2 evolves from the first phase of dripwater degassing, and shifts the winter cave air composition toward slightly more depleted values than those calculated for equilibrium. The systematic 13C-enrichment from the soil to the stalagmites at Grotta di Ernesto is independent of drip rate, and forced by the difference in pCO2 between cave water and cave air. This implies that speleothem δ13C values may not be simply interpreted either in terms of hydrology or soil processes. © 2010 Elsevier Ltd.
Sindaco R.,Museo Civico di Storia Naturale |
Metallinou M.,Institute of Evolutionary Biology CSIC UPF |
Pupin F.,Museo Tridentino di Science Naturali |
Fasola M.,University of Pavia |
Carranza S.,Institute of Evolutionary Biology CSIC UPF
Zoologica Scripta | Year: 2012
The Socotra Archipelago, in the north-west Indian Ocean, is considered to be one of the most remote and most biodiversity rich and distinct islands in the world. Often referred to as the 'Galapagos of the Indian Ocean', it was designated a UNESCO World Heritage Natural site in 2008. Despite having a very rich and bizarre fauna and flora with a high level of endemicity at both species and generic levels, the taxonomy of most of the groups is still not clear, and their origin and evolution remain unknown. Reptiles constitute the most relevant vertebrate fauna of the Socotra Archipelago, with 90% of the 30 species and 45% of the 12 genera being found nowhere else in the world. The skinks of the endemic species Trachylepis socotrana are the only reptile species in the Archipelago distributed across all four islands (Socotra, Darsa, Samha and Abd Al Kuri). Although the species is very well known from Socotra Island, it was not discovered on Samha until 1999 and on Darsa until 2000, whereas only a few citations and one single Museum specimen exist for the population from Abd Al Kuri. To clarify the systematics, biogeography and evolution of Trachylepis socotrana, we assembled a dataset for Mabuya sensu lato including 904 base pairs (bp) of sequence (392 bp from the 12S and 512 from the 16S rRNA mitochondrial genes) for 115 individuals, including specimens of T. socotrana from all four island populations, numerous representatives of the genus Trachylepis from the Middle East, Africa and Madagascar, plus some individuals from each of the other three genera of Mabuya sensu lato (Chioninia, Eutropis and Mabuya). The results of the phylogenetic analyses indicate that, contrary to what was previously thought, members of the genus Trachylepis have colonized the Socotra Archipelago in two independent events, with the first giving rise to the populations from Socotra, Samha and Darsa and the second to the Trachylepis from Abd Al Kuri Island. According to the calibrations, both colonization events occurred within the last fourteen million years, when the Socotra Archipelago had already drifted away from Arabia, thus ruling out vicariance. Both morphological and genetic data show that the Trachylepis from Abd Al Kuri is a distinct taxon, which is herein described as a new species belonging to the T. brevicollis species complex. On the basis of this evidence, the terrestrial herpetofauna from Abd Al Kuri is composed exclusively of endemic species (one of which, the gecko Pristurus abdelkuri, was introduced into some parts of Socotra). © 2012 The Authors. Zoologica Scripta © 2012 The Norwegian Academy of Science and Letters.
Miorandi R.,Museo Tridentino di Science Naturali |
Borsato A.,Museo Tridentino di Science Naturali |
Frisia S.,University of Newcastle |
Fairchild I.J.,University of Birmingham |
Richter D.K.,Ruhr University Bochum
Hydrological Processes | Year: 2010
Grotta di Ernesto is a cave site well suited for palaeoclimate studies because it contains annually laminated stalagmites and was monitored from 1995 to the end of 2008 for microclimate, hydrology and hydrochemistry. Long-term monitoring highlighted that cave drips show three different hydrological responses to rainfall and infiltration: (1) fast seasonal drips in the upper part of the cave, which are mostly fed by fractures, (2) slow seasonal drips, located at mid-depth in the cave characterized by mixed feeding and (3) slow drips, mostly located in the deeper gallery, which are fed by seepage flow from bulk porosity with a minor fracture-fed component. The slow drips display daily cycles during spring thaw. Monitoring also indicated that drip waters are only slightly modified by degassing within the soil zone and aquifer and by prior calcite precipitation. Hydrochemical studies show a clear seasonality in calcite saturation index, which results in most cave calcite precipitation occurring during late autumn and winter with similar amounts of precipitated calcite on most stalagmites, regardless of drip rate (discharge) differences. Drip rate, and drip rate variability, therefore, has a minor role in modulating the amount of annual calcite formation. In contrast, drip rate, when associated with moderate reduction in calcite saturation index, clearly influences stalagmite morphology. Increasing drip rate yields a passage from candle-, to cone- to dome-shaped stalagmites. Very high drip rates feed speleothems with flowstone morphology. In summary, monitoring provides information about the karst aquifer and how hydrology influences those physical and chemical characteristics of speleothems which are commonly used as climate proxies. © 2010 John Wiley & Sons, Ltd.
Bini C.,University of Venice |
Sartori G.,Museo Tridentino di Science Naturali |
Wahsha M.,University of Venice |
Fontana S.,University of Venice
Journal of Geochemical Exploration | Year: 2011
Trace elements of both lithogenic and anthropogenic origin occur in soils distributed in various solid state forms, in the organic fraction and in the soil solution, and their fate in the environment depends upon several factors. The distribution patterns of element concentration are primarily influenced by the lithology of parent material, and secondly by the soil forming processes, that modify the basic geochemical composition and redistribute the content of metals within the soil profile. Alteration processes may lead to the release of potentially toxic elements, particularly heavy metals, into the environment. In this study, our objectives were to evaluate the background level and the concentration range of heavy metals in soils of a famous environmental scenery in northern Italy, to ascertain metal distribution and to identify possible contamination of some sites, and the related environmental hazard, with special reference to the pollution of the Dolomites area, which is a unique and delicate ecosystem. A regional soil survey was carried out in recent years in forested areas of the Trentino Region, in northern Italy. The territory investigated extends over approximately 400,000. ha (70% of the whole region), mostly in mountain areas. Approximately 460 soil samples from more than 120 representative soil profiles were collected and analysed for routine analyses and total Cu, Ni, Pb, Cd, Zn, Cr, Fe, Mn contents. Soils were grouped into 5 groups according to their pedogenetic characteristics. Most soil horizons (260) have acid reaction (mean pH = 6.1), though many are developed from calcareous rocks. Soil texture varies from sandy loam to silty loam. Cation exchange capacity varies consistently with the nature of parent material, as well as base saturation. The organic matter content is generally high at surface, and decreases with depth, the richest horizons (up to 11%) being those from calcareous materials. Background levels of trace elements in the soils investigated are consistent with currently recorded trace element concentration of soils from Western Europe. A geological matrix effect may be accounted for metal release by parent material weathering. Therefore, no contamination is recorded in the whole Trentino region. Nevertheless, metal accumulation in surface horizons at some sites may be ascribed to atmospheric input from local agricultural or industrial activities. Statistical analysis of geochemical data enhanced identification of pedogenetic processes responsible for the formation of soil groups with different weathering stages, and proved a useful tool to outline pedogenetic trends. © 2010 Elsevier B.V.
Bernardi M.,Museo Tridentino di Science Naturali |
Avanzini M.,Museo Tridentino di Science Naturali
Journal of Paleontology | Year: 2011
An Erpetopus trackway recorded in the Lower Permian Collio Formation (Orobic Alps, northern Italy) is investigated as a source of data to reconstruct ancestral patterns of locomotion in eureptiles. The inferred small-sized captorhinid-"protorothyridid" producer cut an inclined muddy surface dragging its front limb digits, tail, and belly on the ground. Integrating ichnological and anatomical data we suggest that small captorhinids ("protorothyridids") locomotion was performed with an obligatory, rigid sprawling posture with the trunk only slightly lifted from the substrate in a low, sprawled 'belly walk'. © 2011 The Paleontological Society.
Brambilla M.,Museo Tridentino di Science Naturali |
Pedrini P.,Museo Tridentino di Science Naturali
Bird Conservation International | Year: 2011
As a double-brooded species inhabiting grassland habitats subject to mowing and located at different elevations, the Corncrake Crex crex in the Alps is potentially affected by changes in its breeding habitat within a season, thus leading to shifts in occurrence and habitat association, with potentially relevant consequences for conservation. We investigated Corncrake abundance in four sites in Trento province (N Italy); two sites were defined as 'low elevation' (mean elevation 975 m and 976 m a.s.l., respectively) and two as 'high elevation' (mean elevation 1,173 m and 1,177 m). The number of calling males showed a clear variation in relative abundance between early and late periods of the breeding season; in particular, at low elevation sites, abundance decreased from the early to late periods, while the opposite was recorded at high elevation sites. A mixed model suggested that the number of males decreased in the second half of the breeding season and at high elevations, and changed according to mid-season altitudinal shifts. Conservation strategies for this species should take into account the mid-season territory shift. © 2010 BirdLife International.
Lencioni V.,Museo Tridentino di Science Naturali |
Marziali L.,CNR Institute of Neuroscience |
Rossaro B.,University of Milan
Journal of Limnology | Year: 2011
The diversity and distribution of chironomids (Diptera, Chironomidae) were studied in relation to environmental factors in 81 springs under pristine conditions in the Italian Prealps and Alps (Trentino and Veneto, NE-Italy, 46°N, 10-11°E). Each spring was surveyed once, between May and November, in 2005 or in 2007-2008, within 50 m of the spring's source (eucrenal). A total of 173 macroinvertebrate samples were collected, in which 26,871 chironomids (including larvae, pupae, pupal exuviae and adults) were counted. Five subfamilies (Tanypodinae, Diamesinae, Prodiamesinae, Orthocladiinae and Chironominae), 54 genera and 104 species/groups of species were identified. As expected, Orthocladiinae accounted for a large part of specimens (82%), followed by Diamesinae (10%), Chironominae Tanytarsini (6%) and Tanypodinae (2%). Together the Chironominae Chironomini and Prodiamesinae contributed less than 0.05% of the fauna. Larvae represented 97.5% of specimens, mostly juveniles (62.6%). Maximum richness and diversity occurred at intermediate altitudes (ca 900-2100 m a.s.l.). Most taxa were found in a small proportion of sites, and frequencies declined gradually for more widely distributed species. A high number (67%) of rare (= present in less than 10% of sites) taxa were found. Three to 27 taxa were identified per spring. The rheocrene/rheo-helocrene springs were richest in taxa (generally >15 taxa), the mineral spring was poorest, with only three taxa. Most taxa were crenophilous, including lentic, rheobiontic and bryophilous taxa. A Principal Component Analysis (PCA) was performed including 98 taxa. Axes were interpreted calculating the correlation coefficients between site scores and 24 environmental factors. The species with the highest scores were Pseudokiefferiella parva, Corynoneura sp. A, Metriocnemus eurynotus gr., Paratrichocladius skirwithensis and Tvetenia calvescens. Five clusters of sites were identified with K-means analysis on the basis of the first and second PCA axes and a Discriminant Analysis was used to detect environmental factors discriminating the clusters: altitude, canopy cover, hydrological regime, pH, and granulometry as percentage of cobbles and stones. The highly individual nature of springs was highlighted; within the same river basin, between springs and within a single spring. These results suggest that prudent and conservative land management should assume that all springs sheltering such unique faunal assemblages need protection.
Lane C.S.,University of Oxford |
Blockley S.P.E.,Royal Holloway, University of London |
Lotter A.F.,University Utrecht |
Finsinger W.,Montpellier University |
And 2 more authors.
Quaternary Science Reviews | Year: 2012
This paper summarises the results of tephrochronological investigations into a suite of central and southern European records, which include: Rotmeer, southern Germany; Soppensee and Rotsee, central Swiss Plateau; Lago di Lavarone and Lago Piccolo di Avigliana, Italian southern Alpine foreland. These sites provide records of palaeoenvironmental changes for the Last Glacial to Interglacial Transition (LGIT) at the boundary between North Atlantic and Mediterranean climatic influences. Chemical characterisation of glass shards in volcanic ash layers indicates that multiple volcanic sources have contributed to the central European tephra record. Amongst other volcanic markers, the Laacher See Tephra, originating from the Eifel region of Germany c. 12.9 ± 0.1 ka, and the Vedde Ash from Iceland c. 12.1 ± 0.1 ka, are found co-located within the sediments of Rotmeer, Soppensee, Rotsee and Lago Piccolo di Avigliana. These key horizons, which bracket the onset of the Younger Dryas stadial, provide precise calendrically-dated tie points around which a detailed picture of the timing of local and regional environmental transitions can be constructed. Using the co-located tephra layers the re-colonisation of Northern Italian catchment areas by Quercus is shown to occur just prior to the deposition of the Laacher See Tephra layer, whereas to the North of the Alps Quercus and other thermophilous trees do not reappear until several centuries after the deposition of the Vedde Ash. Furthermore, the discovery of the Vedde Ash in Lago Piccolo di Avigliana and Lago di Lavarone is indicative of atmospheric transport of polar air into southern Europe during the Younger Dryas stadial, matching evidence proposed for such transport of polar air during the Last Glacial Maximum (LGM). © 2010 Elsevier Ltd.
Egli M.,University of Zürich |
Sartori G.,Museo Tridentino di Science Naturali |
Mirabella A.,Instituto Sperimentale per lo Studio e la Difesa del Suolo |
Giaccai D.,Instituto Sperimentale per lo Studio e la Difesa del Suolo
Geomorphology | Year: 2010
The main aim of this study was to examine the influence of exposure and consequently climate, on the chemical weathering of soils which had developed after the ice retreat of the last glaciation in Northern Italy. This was done by comparing soils developing at north- and south-facing sites on siliceous parent material. There is very little data available on weathering rates and organic matter (OM) as a function of climate and exposure in such environments. Weathering rates (elemental leaching) over the whole lifetime of the soils are higher on north-facing sites. Total organic C and N contents, organic matter stocks and organic matter fractions were analysed to decipher the causes of this difference in weathering behaviour. For the organic matter fractions, we compared the easily oxidisable and stable (resistant to H2O2 treatment) organic matter fractions, water-soluble phenolic materials and alkaline-extractable fractions of the various sites. The abundance of soil organic carbon (SOC) tends to have a non-linear climate dependency. The highest amounts of SOC were measured near the timberline. In addition, compared to south-facing sites, soils on north-facing slopes have a higher organic matter content and a significantly lower degree of humification. Undecomposed or weakly degraded organic matter accumulated on north-facing sites due to less favourable thermal conditions and a higher acidity. With northern exposure, fulvic acids were more easily transported within the soil profile than humic acids and predominately gave rise to the migration (eluviation) of Fe and Al compounds due to their -COOH and -OH functional groups. Furthermore, water-soluble phenolic materials, which are more abundant on north-facing sites, have accelerated the leaching of Al. Accumulation of weakly degraded OM and the subsequently higher production of organic ligands have enhanced the eluviation of Fe and Al. Patterns of weathering processes in Alpine environments are strongly linked to biological and (micro)climatic factors which give rise to distinct differences between north- and south-facing sites. © 2009 Elsevier B.V. All rights reserved.
Avanzini M.,Museo Tridentino di Science Naturali |
Pinuela L.,Museo del Jurasico de Asturias MUJA |
Pinuela L.,University of Oviedo |
Garcia-Ramos J.C.,Museo del Jurasico de Asturias MUJA |
Garcia-Ramos J.C.,University of Oviedo
Lethaia | Year: 2012
This study describes a set of theropod footprints collected from the Late Jurassic Lastres Formation (Asturias, N Spain). The footprints are natural casts (tracks and undertracks) grouped into three morphotypes, which are characterized by different size frequency, L/W relationship and divarication angles: 'Grallatorid' morphotype, 'Kayentapus-Magnoavipes' morphotype, 'Hispanosauropus' morphotype. The tracks were produced in firm, stiff and soft sediments. The infills of deep tracks, which are typically formed in soft mud, lack fine anatomical details, but they can reveal the walk kinematics of the trackmaker through the morphology of internal track fills and sinking traces. In all footprints, a horizontal outwardly directed translation movement and rotation are recognizable. The amount and geometry of digit penetration in the ground also show a pronounced difference. It can be inferred from the described sample that different theropoda-related ichnogenera share common kinematics. © 2011 The Authors, Lethaia © 2011 The Lethaia Foundation.