152 research outputs found
Early-Middle Pleistocene benthic turnover and oxygen isotope stratigraphy from the Central Mediterranean (Valle di Manche, Crotone Basin, Italy): data and trends
Ostracod faunal turnover and oxygen isotope data (foraminifera) along the Valle di Manche (VdM) section are herein compiled. Specifically, the material reported in this work includes quantitative palaeoecological data and patterns of ostracod fauna framed within a high-resolution oxygen isotope stratigraphy (δ18O) from Uvigerina peregrina. In addition, the multivariate ostracod faunal stratigraphic trend (nMDS axis-1 sample score) is calibrated using bathymetric distributions of extant molluscs sampled from the same stratigraphic intervals along the VdM section. Data and analyses support the research article “Dynamics of benthic marine communities across the Early-Middle Pleistocene boundary in the Mediterranean region (Valle di Manche, Southern Italy): biotic and stratigraphic implications” Rossi et al. [1]
Was the Mediterranean Sea during the Calabrian (Early Pleistocene) a low seasonality environment?
Understanding past seasonal temperature variability in the ocean is essential to evaluate the effects of future climate change on marine ecosystems. Here, we estimate seasonal amplitudes and average water temperature from stable oxygen isotope (δ18Oshell) values assuming δ18Owater values of 0.9±0.1permill (V-SMOV). Fossil valves of the bivalve Arctica islandica were collected from three Pleistocene successions (middle-late Calabrian) in Italy. Biostratigraphic analyses from Tacconi Quarry deposits (Rome) indicate an age between 1.6 and 1.2 Ma, while Augusta and Cutrofiano (Lecce) successions are slightly more recent (1.1 and 0.62 Ma, respectively). Prior to carbonate geochemical analysis, we checked the shells for potential diagenetic alterations (e.g., from aragonite to calcite). Stable oxygen isotope (δ18Oshell) profiles of eleven fossil A. islandica valves all depict a relatively low seasonality scenario. δ18Oshell amplitudes vary between 0.4permill and 1.1permill implying a reconstructed seasonal water temperature amplitude of 1.7 ̊C to 4.8 ̊C. The reconstructed average water temperature for the Sicilian population (i.e., 9 valves) is 9.5±0.47 ̊C for δ18Owater 0.9±0.1permill and coincides well with temperature requirements for modern A. islandica. The low seasonality scenario (ca. 3 ̊C) represented by the shells and the low reconstructed water temperatures, colder than modern water temperatures let to the conclusion that the shells lived during a maximum glacial phase when relatively constant water temperatures prevailed throughout the year
Resilient biotic response to long-term climate change in the Adriatic Sea
Preserving adaptive capacities of coastal ecosystems, which are currently facing the ongoing climate warming and a multitude of other anthropogenic impacts, requires an understanding of long-term biotic dynamics in the context of major environmental shifts prior to human disturbances. We quantified responses of nearshore mollusk assemblages to long-term climate and sea-level changes using 223 samples (similar to 71,300 specimens) retrieved from latest Quaternary sediment cores of the Adriatic coastal systems. These cores provide a rare chance to study coastal systems that existed during glacial lowstands. The fossil mollusk record indicates that nearshore assemblages of the penultimate interglacial (Late Pleistocene) shifted in their faunal composition during the subsequent ice age, and then reassembled again with the return of interglacial climate in the Holocene. These shifts point to a climate-driven habitat filtering modulated by dispersal processes. The resilient, rather than persistent or stochastic, response of the mollusk assemblages to long-term environmental changes over at least 125 thousand years highlights the historically unprecedented nature of the ongoing anthropogenic stressors (e.g., pollution, eutrophication, bottom trawling, and invasive species) that are currently shifting coastal regions into novel system states far outside the range of natural variability archived in the fossil record
Coral-algal Reef Complex of Vigoleno, Piacenza, Northern Italy
During the late Miocene, reef complexes characterised by poorly diversified coral associations (mainly Porites, occasionally associated with Tarbellastraea and/or Siderastraea), became widespread in the Mediterranean area. One of these complexes crops out at Vigoleno (Castell'Arquato, Piacenza, Northern Italy). According to the regional palaeogeographic and palinspastic reconstructions, it can be considered up to now the northernmost late Miocene (Tortonian-Messinian) reef of the Mediterranean area. Despite the limited outcropping and the faulting, the multidisciplinary investigations reveal the anatomy of this reef complex along two reference sections. In addition, a marked cyclicity characterises both carbonate and siliciclastic deposits of the Vigoleno wedge-top basin. At present, the lack of reliable geochronological markers and unsuitability of the material for stable isotope analyses are not sufficient to constrain the time-span and the main controlling environmental factors of these depositional cycles
Chemerin expression marks early psoriatic skin lesions and correlates with plasmacytoid dendritic cell recruitment
Psoriasis is a type I interferon-driven T cell–mediated disease characterized by the recruitment of plasmacytoid dendritic cells (pDC) into the skin. The molecules involved in pDC accumulation in psoriasis lesions are unknown. Chemerin is the only inflammatory chemotactic factor that is directly active on human blood pDC in vitro. The aim of this study was to evaluate the role of the chemerin/ChemR23 axis in the recruitment of pDC in psoriasis skin. Prepsoriatic skin adjacent to active lesions and early lesions were characterized by a strong expression of chemerin in the dermis and by the presence of CD15+ neutrophils and CD123+/BDCA-2+/ChemR23+ pDC. Conversely, skin from chronic plaques showed low chemerin expression, segregation of neutrophils to epidermal microabscesses, and few pDC in the dermis. Chemerin expression was localized mainly in fibroblasts, mast cells, and endothelial cells. Fibroblasts cultured from skin of psoriatic lesions expressed higher levels of chemerin messenger RNA and protein than fibroblasts from uninvolved psoriatic skin or healthy donors and promoted pDC migration in vitro in a chemerin-dependent manner. Therefore, chemerin expression specifically marks the early phases of evolving skin psoriatic lesions and is temporally strictly associated with pDC. These results support a role for the chemerin/ChemR23 axis in the early phases of psoriasis development
The 10Be record as a proxy of paleomagnetic reversals and excursions: A Mediterranean perspective
The 10Be/9Be ratio is acknowledged as an effective tool for establishing the stratigraphic position of paleomagnetic excursions. Still, our data suggest that, in particular depositional settings, the interplay between climate, sedimentation and oceanography may jeopardize a realistic depiction of the natural 10Be/9Be record
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