Abstract
Reconstruction of last millennia Sea Surface Temperature (SST) evolution is challenging due to the difficulty retrieving good resolution marine records and to the several uncertainties in ...the available proxy tools. In this regard, the Roman Period (1 CE to 500 CE) was particularly relevant in the socio-cultural development of the Mediterranean region while its climatic characteristics remain uncertain. Here we present a new SST reconstruction from the Sicily Channel based in Mg/Ca ratios measured on the planktonic foraminifer
Globigerinoides ruber
. This new record is framed in the context of other previously published Mediterranean SST records from the Alboran Sea, Minorca Basin and Aegean Sea and also compared to a north Hemisphere temperature reconstruction. The most solid image that emerges of this trans-Mediterranean comparison is the persistent regional occurrence of a distinct warm phase during the Roman Period. This record comparison consistently shows the Roman as the warmest period of the last 2 kyr, about 2 °C warmer than average values for the late centuries for the Sicily and Western Mediterranean regions. After the Roman Period a general cooling trend developed in the region with several minor oscillations. We hypothesis the potential link between this Roman Climatic Optimum and the expansion and subsequent decline of the Roman Empire.
Twelve anomalous layers, marked by a high concentration of displaced epiphytic foraminifera (species growing in vegetated substrates like the
Posidonia oceanica) and subtle grain-size changes were ...found in a 6.7
m long, fine sediment core (MS-06), sampled 2
km off the shore of the Augusta Harbor (Eastern Sicily) at a depth of 72
m, recording the past 4500
yrs of deposition. Because concentrations of epiphytic foraminifera are quite common in infralittoral zones, but not expected at −
72
m, we believe that these anomalous layers might be related to the occurrence of tsunamis causing substantial uprooting and seaward displacement of
P. oceanica blades with their benthic biota.
Our approach involved the study of geophysical data (morphobathymetry, seismic reflection, and seafloor reflectivity) and sediment samples, including X-ray imaging, physical properties, isotopic dating, tephrochronology, grain-size and micropaleontology.
Correlations between anomalous layers and tsunami events have been supported by a multivariate analysis on benthic foraminifera assemblage and dates of historical tsunami records. We found that four out of the eleven layers were embedded in age intervals encompassing the dates of major tsunamis that hit eastern Sicily (1908, 1693, and 1169) and the broader Eastern Mediterranean (Santorini at about BP 3600). One more layer, even if less distinct than the others, was also defined and may be the evidence for the AD 365 Crete tsunami.
► We explored offshore multidisciplinary approaches for paleotsunami research. ► High resolution analyses highlighted subtle anomalies in the core sediments. ► Twelve anomalous (grain-size and foraminifera) layers deposited in the past 4500 yrs. ► Anomalous layers can be related to high energy events only. ► Tsunami backwash could be the effective mechanism.
We present a high-resolution paleoclimatic and paleoenvironmental reconstruction of the last five millennia from a shallow water marine sedimentary record from the central Tyrrhenian Sea (Gulf of ...Gaeta) using planktonic foraminifera, pollen, oxygen stable isotope, tephrostratigrapy and magnetostratigrapy. This multiproxy approach allows to evidence and characterize nine time intervals associated with archaeological/cultural periods: Eneolithic (base of the core–ca. 2410BCE), Early Bronze Age (ca. 2410BCE–ca. 1900BCE), Middle Bronze Age–Iron Age (ca. 1900BCE–ca. 500BCE), Roman Period (ca. 500BCE–ca. 550CE), Dark Age (ca. 550CE–ca. 860CE), Medieval Climate Anomaly (ca. 860CE–ca. 1250CE), Little Ice Age (ca. 1250CE–ca. 1850CE), Industrial Period (ca. 1850CE–ca. 1950CE), Modern Warm Period (ca. 1950CE–present day). The reconstructed climatic evolution in the investigated sedimentary succession is coherent with the short-term climate variability documented at the Mediterranean scale.
By integrating the planktonic foraminiferal turnover from carnivorous to herbivorous–opportunistic species, the oxygen isotope record and the pollen distribution, we document important modification from the onset of the Roman Period to the present-day. From ca. 500CE upwards the documentation of the cooling trend punctuated by climate variability at secular scale evidenced by the short-term δ18O is very detailed. We hypothesise that the present day warm conditions started from the end of cold Maunder event. Additionally, we provide that the North Atlantic Oscillation (NAO) directly affected the central Mediterranean region during the investigated time interval.
•A high-resolution paleoclimate reconstruction for the last five millennia is proposed.•Planktonic foraminifera and pollen records combined with oxygen stable isotope allow us to characterize climate phases.•Oxygen isotopic record performed on Globigerinoides ruber results in phase with the North Atlantic Oscillation (NAO).
Since the late 70s, the Early Pleistocene (Gelasian) site of Coste San Giacomo (Anagni Basin, central Italy) has been known amongst palaeontologists for its diverse vertebrate fauna. During the last ...5 years, new excavations and the drilling of a 46-m-deep core have provided novel pieces of information. Palaeomagnetic data, pollen and small vertebrates analyses are presented here for the first time and combined with the updated list of the large vertebrates and ostracod analysis in a multidisciplinary perspective. Large and small mammals, pollen and ostracod analyses have allowed an integrated palaeoenvironmental reconstruction of the sedimentary sequence, depicting the evolution of the alluvial plain in the surrounding landscape. Moreover, magnetostratigraphy, pollen and small mammal biochronological data have confirmed the position of the Coste San Giacomo Faunal Unit, focusing the possible age of the mammal assemblage around 2.1 Ma, in a reversed phase before the base of the Olduvai chron. In particular, the occurrence of the large vole Mimomys pliocaenicus has important biochronological significance. The Coste San Giacomo site offers a unique opportunity to investigate the faunal and environmental changes that occurred in Mediterranean Europe during the Early Pleistocene, coinciding with major climatic changes at a global scale. The occurrence of taxa such as Hippopotamus sp. in the assemblage provides evidence of early dispersal events of African taxa prior to the early Homo diffusion into Europe.
The 1999 Mw 7.4 earthquake triggered a tremendous human tragedy and had a great social impact over the population of the İzmit Bay, one of the most industrialized area of Turkey. Although the ...successive environmental disasters were well documented, information on its sedimentary record is lacking. The present research aims at filling this gap, through the analysis of organic contaminants (PCBs, PAHs, and PBDEs) in a dated sediment core collected in the depocenter of the Karamürsel Basin in 2005. Profiles of total PCBs and total PAHs overlap the timing of industrialization in the area (starting in the 1960s) with values increasing as the population and the number of industrial plants grew larger. Profiles for PBDEs are in accordance with increasing urban inputs but are probably affected by processes of natural formation and post-depositional mixing. The continuous sedimentary record is interrupted at a level dating back to 1980 due to the erosion caused by the 1999 earthquake, having removed a 5–7cm thick sediment layer. Contaminant concentrations in the deepest 10–15cm of a 30cm thick seismo-turbidite unit, triggered by the 1999 event, increase with the progressive fining up and evidence massive transport of sediments from coastal, more polluted sites of the north-eastern Karamürsel shelves and shores. Additional inputs of PAHs are also evident, originating from a fire at the oil refinery that followed the shaking. The effects of the earthquake generated tsunami, its backwash fluxes and the following seiches are not uniquely displayed by each class of contaminants, and they could probably reflect successive inputs deriving from different parts of the basin that are subject to anthropogenic impacts of different nature. Concentrations measured at the top of the core are consistent with an unvaried input of pollutants in the period 1980–2005.
Display omitted
•On August 17th 1999 an earthquake of Mw=7.4 hit the İzmit Bay in the Marmara Sea.•PCBs, PAHs, and PBDEs were measured in a sediment core from the Marmara Sea in 2005.•Contaminant profiles well overlap the timing of industrialization in the area.•The massive transport of contaminated sediments is evidenced in the seismo-turbidite.•A scenario of unvaried inputs of pollutants is defined for the period 1980–2005.
Abstract
Weather routing (WR) systems are widely adopted in the maritime transport since safety of goods and saving of fuel are crucial for shipping companies. However, the need of protecting the ...local coasts and reducing CO
2
emission is making WR attractive even for the market of leisure boats, especially if comfort and safety are also accounted. In the present study, a prototype of a WR system is presented. The developed tool implements the Dijkstra’s algorithm to find the fuel-optimal path while ensuring comfort and safety. A computationally efficient digital twin of a planing boat, based on a 2D+t model and a powertrain mapped model, has been implemented for the estimation of the fuel consumption and the evaluation of vertical accelerations. The methodology for the acquisition of online weather data is presented, together with the strategy for the assessment of comfort and habitability. The application of the WR tool in a typical path of the Tuscan Archipelago shows improvements in fuel usage and comfort even in moderate weather conditions. The influence of each weather variable on fuel efficiency is assessed, highlighting the requirement of an accurate dynamic modelling. Criteria for the graph design are also outlined, showing a wrong estimation of comfort and fuel usage in case of low-definition graphs. The paper proves the potential and the effectiveness of the developed tool, moving toward a greener and more comfortable navigation in local seas.
The Calabrian Arc subduction system is part of the Africa–Eurasia plate boundary, is one of the most seismically active regions in the Mediterranean Sea, and has been struck repeatedly by destructive ...historical earthquakes. In this study, we investigate the effects of historical earthquakes on abyssal marine sedimentation through the analysis of the turbidite record. We collected gravity cores in tectonically controlled basins where the eastern Mediterranean pelagic sequence is interbedded with resedimented units. Textural, micropaleontological, geochemical, and mineralogical signatures reveal three turbidite events in the last millennium. We dated the turbidite sequences from two different cores using different radiometric methods, whereas the average time interval between successive turbidite beds was estimated from pelagic sediment thickness and sedimentation rates; chronologies were refined through age modeling that provided age ranges (2σ) of each turbidite bed. The results suggest that turbidite emplacement was triggered by three historical earthquakes recorded in the area (i.e., the 1908, 1693, and 1169 events); their magnitude, epicentral location, and associated tsunamis support causative faults located in the Ionian Sea. The source for all the turbidites, as inferred from their mineralogy, is the metamorphic basement outcropping in southern Calabria and/or northeastern Sicily. Turbidite composition and cable breaks for the 1908 event have been used to infer likely traveling paths and seismogenic faults in the subduction system. Our findings suggest that Ionian Sea turbidites represent more than 80% of sedimentation and may be seabed archives of paleo‐earthquakes capable of reconstructing seismicity back in time, during several earthquake cycles.
Key Points
We examine interplay between historical seismicity, mass failures and turbidites
We reconstruct chronology of earthquake triggered turbidites in the Ionian Sea
Turbidite composition has been used to reconstruct sediment source
H2A.Z association with specific genomic loci is thought to contribute to a chromatin structure that promotes transcription activation. Acetylation of H2A.Z at promoters of oncogenes has been linked ...to tumorigenesis. The mechanism is unknown. Here, we show that in triple negative breast cancer cells, H2A.Z bound to the promoter of the constitutively, weakly expressed cyclin D1 oncogene (CCND1), a key regulator of cellular proliferation. Depleting the pool of H2A.Z stimulated transcription of CCND1 in the absence of its cognate transcription factor, the estrogen receptor (ER). During activation of CCND1, H2A.Z was released from the transcription start site (TSS) and downstream enhancer (enh2) sequences. Concurrently, acetylation of H2A.Z, H3 and H4 at the TSS was increased but only H2A.Z was acetylated at enh2. Acetylation of H2A.Z required the Tip60 acetyltransferase to be associated with the activated CCND1 on both TSS and enh2 sites. Depletion of Tip60 prevented CCND1 activation. Chromosome conformation capture experiments (3C) revealed specific contacts between the TSS and enh2 chromatin regions. These results suggest that release of a histone H2A.Z-mediated repression loop activates CCND1 for transcription. Our findings open new avenues for controlling and understanding aberrant gene expression associated with tumorigenesis.
Sedimentary earthquake records of the last 2400a, including that of the devastating 17 August 1999 İzmit earthquake (Mw=7.4), were studied in cores from the 210m-deep central Karamürsel Basin of the ...İzmit Gulf in the eastern Sea of Marmara, using laser grain-size, physical properties, stable O and C isotopes and XRF Core Scanner analyses, and dated by radionuclide and radiocarbon methods. The earthquake records are represented by turbidite–homogenite mass-flow units (THU) that commonly contain a basal coarse layer, a middle laminated silt layer and an overlying homogeneous mud layer. The coarse basal part has a sharp and sometimes scoured lower boundary, and includes multiple coarse (sand/silt) layers or laminae showing normal size grading. Multiple coarse layers and occasional bi-directional cross-bedding suggest deposition from a bed-load during water column oscillations, or seiche effect. The grain-size characteristics of the overlaying laminated silt and the homogeneous mud units indicate deposition from weak oscillating currents and homogeneous suspension, respectively. High Mn value just below the base of THUs suggests diagenetic enrichment at oxic/anoxic redox boundary before the mass-flow event. Sharp decrease in Mn with very low values within the THUs suggests transient redox conditions following the mass-flow. Variable geochemical compositions of the basal coarse layers indicate different sediment sources for different THUs. Eight sedimentary earthquake records observed in the last 2400a in the İzmit Gulf can be confidently correlated with the historical earthquakes of 1999, 1509AD (Ms=7.2), 1296AD (I=VII), 865AD (I=VIII), 740AD (I=VIII), 268AD (I=VIII), 358AD (I=IX), and 427 BC. This gives an earthquake recurrence time of ca. 300a, with the interval between consecutive events ranging from 90 to 695a.
Twenty-four surficial sediment samples, representing different environments within the Venice Lagoon, were analyzed for polychlorinated biphenyls (PCBs) in order to assess degrees of pollution, ...sources, areal distribution, and potential risk for the environment. Concentrations in surficial sediments range from 2 to more than 2049 μg kg
−1 dw. The maximum is probably due to the discharge of industrial wastes into the Brentella Canal, within the first Industrial Area. Lagoon samples are 11–205 times less contaminated, being influenced by pollutants stored in the canals only occasionally. Congener profiles distinguish PCBs in two main categories. The baseline pollution is probably due to a variety of sources within the lagoon system, whereas less chlorinated PCBs were discharged into the Brentella Canal. Our estimates suggest that, due to high concentrations, toxic equivalents (TEQs) of PCBs are comparable to those relative to PCDD/Fs for the least contaminated samples, whereas they are lower in case of heavy PCDD/F contamination.
PDF
