Taviani Marco

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  • Preprint
    Exploring the oxygen and carbon isotopic composition of the Mediterranean red coral (Corallium rubrum) for seawater temperature reconstruction
    ( 2016-07) Chaabane, Sonia ; Lopez Correa, Matthias ; Montagna, Paolo ; Kallel, Nejib ; Taviani, Marco ; Linares, Cristina ; Ziveri, Patrizia
    Here we provide first evidence that the stable oxygen and carbon isotopic composition (δ18O, δ13C) of the high-magnesium calcite skeleton red coral Corallium rubrum can be used as a reliable seawater temperature proxy. This is based upon the analyses of living colonies of C. rubrum from different depths and localities in the Western Mediterranean Sea. The assessment of the growth rates has been established through the analysis of growth band patterns. The δ18O and δ13C compositions show large variability with a significant difference between the branches and the bases of the colonies. In both coral portions, the δ18O and δ13C values are highly correlated and show well-defined linear trends. Following the “lines technique” approach developed by Smith et al. (2000) for scleractinian aragonitic deep-water corals, our data have been combined with published values for the deep-sea gorgonian corals Isididae and Coralliidae from Kimball et al. (2014) and Hill et al. (2011) resulting in the following δ18O temperature equation: T (°C) = 38 -5.05 ± 0.24 x (δ18Ointercept) + 14.26 ± 0.43 (R² = 0.962, p value < 0.0001) The error associated with this equation is ± 0.5 °C at the mean temperature of the data set, ± 0.7 °C for corals living in 2 °C water and ± 1 °C for coral living in warmer water (17 °C). The highly significant δ18Ointercept vs. temperature relationship combined with the “lines technique” method can be reliably applied to the calcitic skeleton to obtain calcification temperature estimates in the past, although this approach requires the knowledge of the past δ18O and δ13C composition of seawater and it is labor and time intensive.
  • Article
    Identifying priorities for the protection of deep Mediterranean Sea ecosystems through an integrated approach
    (Frontiers Media, 2021-07-22) Fanelli, Emanuela ; Bianchelli, Silvia ; Foglini, Federica ; Canals, Miquel ; Castellan, Giorgio ; Güell-Bujons, Queralt ; Galil, Bella S. ; Goren, Menachem ; Evans, Julian ; Fabri, Marie-Claire ; Vaz, Sandrine ; Ciuffardi, Tiziana ; Schembri, Patrick J. ; Angeletti, Lorenzo ; Taviani, Marco ; Danovaro, Roberto
    Benthic habitats of the deep Mediterranean Sea and the biodiversity they host are increasingly jeopardized by increasing human pressures, both direct and indirect, which encompass fisheries, chemical and acoustic pollution, littering, oil and gas exploration and production and marine infrastructures (i.e., cable and pipeline laying), and bioprospecting. To this, is added the pervasive and growing effects of human-induced perturbations of the climate system. International frameworks provide foundations for the protection of deep-sea ecosystems, but the lack of standardized criteria for the identification of areas deserving protection, insufficient legislative instruments and poor implementation hinder an efficient set up in practical terms. Here, we discuss the international legal frameworks and management measures in relation to the status of habitats and key species in the deep Mediterranean Basin. By comparing the results of a multi-criteria decision analysis (MCDA) and of expert evaluation (EE), we identify priority deep-sea areas for conservation and select five criteria for the designation of future protected areas in the deep Mediterranean Sea. Our results indicate that areas (1) with high ecological relevance (e.g., hosting endemic and locally endangered species and rare habitats),(2) ensuring shelf-slope connectivity (e.g., submarine canyons), and (3) subject to current and foreseeable intense anthropogenic impacts, should be prioritized for conservation. The results presented here provide an ecosystem-based conservation strategy for designating priority areas for protection in the deep Mediterranean Sea.
  • Article
    A 1000-yr-old tsunami in the Indian Ocean points to greater risk for East Africa: reply
    (Geological Society of America, 2020-12-22) Maselli, Vittorio ; Oppo, Davide ; Moore, Andrew L. ; Gusman, Aditya Riadi ; Mtelela, Cassy ; Iacopini, David ; Taviani, Marco ; Mjema, Elinaza ; Mulaya, Ernest ; Che, Melody ; Tomioka, Ai Lena ; Mshiu, Elisante ; Ortiz, Joseph D.
    We appreciate Somerville’s (2020) interest in our work, and the opportunity to further expand the discussion about the occurrence of a trans-oceanic tsunami in the Indian Ocean generated by a megathrust earthquake ~1000 years ago. Somerville suggests a connection between the inferred tsunami deposit presented by us (Maselli et al., 2020) and a tsunami event reported to have occurred in Nagapattinam (India) in the year 900 CE and described in Kalaki Krishnamurty’s book (Rastogi and Jaiswal, 2006).
  • Article
    A unique and threatened deep water coral-bivalve biotope new to the Mediterranean Sea offshore the Naples megalopolis
    (Nature Research, 2019-03-04) Taviani, Marco ; Angeletti, Lorenzo ; Cardone, Frine ; Montagna, Paolo ; Danovaro, Roberto
    The Gulf of Naples is an example of the most beautiful and biodiverse marine regions of the Mediterranean Sea and of the most impacted areas in terms of industrial activities, large contaminated areas, resource exploitation, infrastructures at sea and maritime transportation. We conducted Remotely Operated Vehicle surveys in the Dohrn Canyon in the Tyrrhenian Sea at approximately 12 NM off Naples metropolitan area, and revealed a hotspot of deep-sea benthic biodiversity of sessile fauna at ca. 400 m depth. The hard bottoms are characterized by a high abundance of charismatic species, such as the habitat forming cold-water corals (CWC) Madrepora oculata, Lophelia pertusa, Desmophyllum dianthus in association with the large size bivalves Acesta excavata and Neopycnodonte zibrowii. This CWC-bivalve co-occurrence represents a novel biotope for the Mediterranean Sea, which coexists with the evidence of severe anthropogenic threats, such as illegal dumping and fishery malpractices that were visually documented during the survey. We recommend the adoption of specific protection measures to preserve these unique deep-sea assemblages showing the uncommon co-existence of such a number of deep-sea species in a single habitat.
  • Article
    The influence of temperature and seawater carbonate saturation state on 13C–18O bond ordering in bivalve mollusks
    (Copernicus Publications on behalf of the European Geosciences Union, 2013-07-10) Eagle, Robert A. ; Eiler, John M. ; Tripati, Aradhna K. ; Ries, J. B. ; Freitas, P. S. ; Hiebenthal, C. ; Wanamaker, Alan D. ; Taviani, Marco ; Elliot, Mary ; Marenssi, S. ; Nakamura, K. ; Ramirez, P. ; Roy, K.
    The shells of marine mollusks are widely used archives of past climate and ocean chemistry. Whilst the measurement of mollusk δ18O to develop records of past climate change is a commonly used approach, it has proven challenging to develop reliable independent paleothermometers that can be used to deconvolve the contributions of temperature and fluid composition on molluscan oxygen isotope compositions. Here we investigate the temperature dependence of 13C–18O bond abundance, denoted by the measured parameter Δ47, in shell carbonates of bivalve mollusks and assess its potential to be a useful paleothermometer. We report measurements on cultured specimens spanning a range in water temperatures of 5 to 25 °C, and field collected specimens spanning a range of −1 to 29 °C. In addition we investigate the potential influence of carbonate saturation state on bivalve stable isotope compositions by making measurements on both calcitic and aragonitic specimens that have been cultured in seawater that is either supersaturated or undersaturated with respect to aragonite. We find a robust relationship between Δ47 and growth temperature. We also find that the slope of a linear regression through all the Δ47 data for bivalves plotted against seawater temperature is significantly shallower than previously published inorganic and biogenic carbonate calibration studies produced in our laboratory and go on to discuss the possible sources of this difference. We find that changing seawater saturation state does not have significant effect on the Δ47 of bivalve shell carbonate in two taxa that we examined, and we do not observe significant differences between Δ47-temperature relationships between calcitic and aragonitic taxa.
  • Article
    New evidence of MIS 3 relative sea level changes from the Messina Strait, Calabria (Italy)
    (MDPI, 2021-09-26) Antonioli, Fabrizio ; Calcagnile, Lucio ; Feranti, Luigi ; Mastronuzzi, Giuseppe ; Monaco, Carmelo ; Orrù, Paolo ; Quarta, Gianluca ; Pepe, Fabrizio ; Scardino, Giovanni ; Scicchitano, Giovanni ; Stocchi, Paolo ; Taviani, Marco
    Investigation of sea-level positions during the highly-dynamic Marine Isotope Stage 3 (MIS 3: 29–61 kyrs BP) proves difficult because: (i) in stable and subsiding areas, coeval coastal sediments are currently submerged at depths of few to several tens of meters below the present sea level; (ii) in uplifting areas, the preservation of geomorphic features and sedimentary records is limited due to the erosion occurred during the Last Glacial Maximum (LGM) with sea level at a depth of −130 m, followed by marine transgression that determined the development of ravinement surfaces. This study discusses previous research in the Mediterranean and elsewhere, and describes new fossiliferous marine deposits overlaying the metamorphic bedrock at Cannitello (Calabria, Italy). Radiocarbon ages of marine shells (about 43 kyrs cal BP) indicate that these deposits, presently between 28 and 30 m above sea level, formed during MIS 3.1. Elevation correction of the Cannitello outcrops (considered in an intermediate-to-far-field position with respect to the ice sheet) with the local vertical tectonic rate and Glacial Isostatic Adjustment (GIA) rate allows the proposal of a revision of the eustatic depth for this highstand. Our results are consistent with recently proposed estimates based on a novel ice sheet modelling technique.
  • Article
    Hydrological variations of the intermediate water masses of the western Mediterranean Sea during the past 20 ka inferred from neodymium isotopic composition in foraminifera and cold-water corals
    (Copernicus Publications on behalf of the European Geosciences Union, 2017-01-10) Dubois-Dauphin, Quentin ; Montagna, Paolo ; Siani, Giuseppe ; Douville, Eric ; Wienberg, Claudia ; Hebbeln, Dierk ; Liu, Zhifei ; Kallel, Nejib ; Dapoigny, Arnaud ; Revel, Marie ; Pons-Branchu, Edwige ; Taviani, Marco ; Colin, Christophe
    We present the neodymium isotopic composition (εNd) of mixed planktonic foraminifera species from a sediment core collected at 622 m water depth in the Balearic Sea, as well as εNd of scleractinian cold-water corals (CWC; Madrepora oculata, Lophelia pertusa) retrieved between 280 and 442 m water depth in the Alboran Sea and at 414 m depth in the southern Sardinian continental margin. The aim is to constrain hydrological variations at intermediate depths in the western Mediterranean Sea during the last 20 kyr. Planktonic (Globigerina bulloides) and benthic (Cibicidoides pachyderma) foraminifera from the Balearic Sea were also analyzed for stable oxygen (δ18O) and carbon (δ13C) isotopes. The foraminiferal and coral εNd values from the Balearic and Alboran seas are comparable over the last  ∼  13 kyr, with mean values of −8.94 ± 0.26 (1σ; n =  24) and −8.91 ± 0.18 (1σ; n =  25), respectively. Before 13 ka BP, the foraminiferal εNd values are slightly lower (−9.28 ± 0.15) and tend to reflect higher mixing between intermediate and deep waters, which are characterized by more unradiogenic εNd values. The slight εNd increase after 13 ka BP is associated with a decoupling in the benthic foraminiferal δ13C composition between intermediate and deeper depths, which started at  ∼  16 ka BP. This suggests an earlier stratification of the water masses and a subsequent reduced contribution of unradiogenic εNd from deep waters. The CWC from the Sardinia Channel show a much larger scatter of εNd values, from −8.66 ± 0.30 to −5.99 ± 0.50, and a lower average (−7.31 ± 0.73; n =  19) compared to the CWC and foraminifera from the Alboran and Balearic seas, indicative of intermediate waters sourced from the Levantine basin. At the time of sapropel S1 deposition (10.2 to 6.4 ka), the εNd values of the Sardinian CWC become more unradiogenic (−8.38 ± 0.47; n =  3 at  ∼  8.7 ka BP), suggesting a significant contribution of intermediate waters originated from the western basin. We propose that western Mediterranean intermediate waters replaced the Levantine Intermediate Water (LIW), and thus there was a strong reduction of the LIW during the mid-sapropel ( ∼  8.7 ka BP). This observation supports a notable change of Mediterranean circulation pattern centered on sapropel S1 that needs further investigation to be confirmed.
  • Article
    Paleochannel and beach-bar palimpsest topography as initial substrate for coralligenous buildups offshore Venice, Italy
    (Nature Publishing Group, 2017-05-02) Tosi, Luigi ; Zecchin, Massimo ; Franchi, Fulvio ; Bergamasco, Andrea ; Da Lio, Cristina ; Baradello, Luca ; Mazzoli, Claudio ; Montagna, Paolo ; Taviani, Marco ; Tagliapietra, Davide ; Carol, Eleonora ; Franceschini, Gianluca ; Giovanardi, Otello ; Donnici, Sandra
    We provide a model for the genesis of Holocene coralligenous buildups occurring in the northwestern Adriatic Sea offshore Venice at 17–24 m depth. High-resolution geophysical surveys and underwater SCUBA diving reconnaissance revealed meandering shaped morphologies underneath bio-concretionned rocky buildups. These morphologies are inferred to have been inherited from Pleistocene fluvial systems reactivated as tidal channels during the post- Last Glacial Maximum transgression, when the study area was a lagoon protected by a sandy barrier. The lithification of the sandy fossil channel-levee systems is estimated to have occurred at ca. 7 cal. ka BP, likely due to the interaction between marine and less saline fluids related to onshore freshwater discharge at sea through a sealed water-table. The carbonate-cemented sandy layers served as nucleus for subsequent coralligenous buildups growth.
  • Article
    Changes in the intermediate water masses of the Mediterranean Sea during the last climatic cycle-new constraints from neodymium isotopes in foraminifera
    (American Geophysical Union, 2021-02-15) Colin, Christophe ; Duhamel, Maxence ; Siani, Giuseppe ; Dubois-Dauphin, Quentin ; Ducassou, Emmanuelle ; Liu, Zhifei ; Wu, Jiawang ; Revel, Marie ; Dapoigny, Arnaud ; Douville, Eric ; Taviani, Marco ; Montagna, Paolo
    Variations in Mediterranean thermohaline circulation of the Quaternary are still not well constrained whereas they have been considered to have an influence on the Atlantic Meridional Overturning Circulation and on the oxygenation of waters in the deep basins of the Mediterranean Sea. εNd analyses have been carried out on planktonic foraminifera of cores collected in the central Mediterranean Sea to constrain water mass exchange between the Eastern and Western Mediterranean Sea (EMS and WMS) during the last climatic cycle. εNd records from the WMS and EMS display similar higher values during warm substages of interglacial Marine Isotopic Stage (MIS) 1 and 5. This suggests an efficient connection between the two Mediterranean sub-basins and the transfer of radiogenic waters to the Tyrrhenian Sea via the Levantine Intermediate Water (LIW). Conversely, during glacial MIS, εNd of the intermediate depth of the Tyrrhenian Sea are less radiogenic than the EMS, implying limited hydrological connection between sub-basins during low sea-level stands. Superimposed on these glacial-interglacial variations, increased εNd occurred during Heinrich Stadial events. This suggests a reduction in the formation of unradiogenic WIW in the Gulf of Lions due to the input of relatively fresh surface Atlantic water to the WMS and/or the inflow of radiogenic glacial LIW and upper EMDW to the Tyrrhenian Sea as a result of an active EMS convection related to saltier and colder conditions. Such potential millennial-scale pulses of LIW intrusion into the Tyrrhenian Sea may have led to an enhanced Mediterranean Outflow Water intensity in the Gibraltar Strait.
  • Article
    A 1000-yr-old tsunami in the Indian Ocean points to greater risk for East Africa
    (Geological Society of America, 2020-05-12) Maselli, Vittorio ; Oppo, Davide ; Moore, Andrew L. ; Gusman, Aditya Riadi ; Mtelela, Cassy ; Iacopini, David ; Taviani, Marco ; Mjema, Elinaza ; Mulaya, Ernest ; Che, Melody ; Tomioka, Ai Lena ; Mshiu, Elisante ; Ortiz, Joseph D.
    The December 2004 Sumatra-Andaman tsunami prompted an unprecedented research effort to find ancient precursors and quantify the recurrence time of such a deadly natural disaster. This effort, however, has focused primarily along the northern and eastern Indian Ocean coastlines, in proximal areas hardest hit by the tsunami. No studies have been made to quantify the recurrence of tsunamis along the coastlines of the western Indian Ocean, leading to an underestimation of the tsunami risk in East Africa. Here, we document a 1000-yr-old sand layer hosting archaeological remains of an ancient coastal Swahili settlement in Tanzania. The sedimentary facies, grain-size distribution, and faunal assemblages indicate a tsunami wave as the most likely cause for the deposition of this sand layer. The tsunami in Tanzania is coeval with analogous deposits discovered at eastern Indian Ocean coastal sites. Numerical simulations of tsunami wave propagation indicate a megathrust earthquake generated by a large rupture of the Sumatra-Andaman subduction zone as the likely tsunami source. Our findings provide evidence that teletsunamis represent a serious threat to coastal societies along the western Indian Ocean, with implications for future tsunami hazard and risk assessments in East Africa.
  • Article
    Drawing the borders of the mesophotic zone of the Mediterranean Sea using satellite data
    (Nature Research, 2022-04-04) Castellan, Giorgio ; Angeletti, Lorenzo ; Montagna, Paolo ; Taviani, Marco
    The 30–150 m bathymetric range is commonly adopted in the literature to constrain the mesophotic zone. However, such depth interval varies depending on sunlight penetration, which is primarily a function of solar radiation incidence and water clarity. This is especially obvious in the Mediterranean Sea with its peculiar biophysical properties. Integrating information on light regime in the estimation of the bathymetric range of the mesophotic zone would provide a more robust definition, orienting conservation actions targeting its ecosystems. We present a first assessment of the spatial and vertical extension of the mesophotic zone in the Mediterranean Sea based upon light penetration, comparing our prediction with literature data. Our study also represents a baseline to monitor future variations in the bathymetric interval associated with the mesophotic zone in the Mediterranean Sea in relation to global changes.
  • Article
    Erratum to: Merging scleractinian genera: the overwhelming genetic similarity between solitary Desmophyllum and colonial Lophelia
    (BioMed Central, 2016-07-19) Addamo, Anna M. ; Vertino, Agostina ; Stolarski, Jaroslaw ; Garcia-Jimenez, Ricardo ; Taviani, Marco ; Machordom, Annie
    As a result of vendor errors being introduced during processing, the original version of this article was published with some duplication errors in Table 1.
  • Article
    Desmophyllum dianthus (Esper, 1794) in the scleractinian phylogeny and its intraspecific diversity
    (Public Library of Science, 2012-11-28) Addamo, Anna M. ; Reimer, James D. ; Taviani, Marco ; Freiwald, Andre ; Machordom, Annie
    The cosmopolitan solitary deep-water scleractinian coral Desmophyllum dianthus (Esper, 1794) was selected as a representative model species of the polyphyletic Caryophylliidae family to (1) examine phylogenetic relationships with respect to the principal Scleractinia taxa, (2) check population structure, (3) test the widespread connectivity hypothesis and (4) assess the utility of different nuclear and mitochondrial markers currently in use. To carry out these goals, DNA sequence data from nuclear (ITS and 28S) and mitochondrial (16S and COI) markers were analyzed for several coral species and for Mediterranean populations of D. dianthus. Three phylogenetic methodologies (ML, MP and BI), based on data from the four molecular markers, all supported D. dianthus as clearly belonging to the “robust” clade, in which the species Lophelia pertusa and D. dianthus not only grouped together, but also shared haplotypes for some DNA markers. Molecular results also showed shared haplotypes among D. dianthus populations distributed in regions separated by several thousands of kilometers and by clear geographic barriers. These results could reflect limited molecular and morphological taxonomic resolution rather than real widespread connectivity. Additional studies are needed in order to find molecular markers and morphological features able to disentangle the complex phylogenetic relationship in the Order Scleractinia and to differentiate isolated populations, thus avoiding the homoplasy found in some morphological characters that are still considered in the literature.
  • Article
    Chemosymbiotic bivalves from the late Pliocene Stirone River hydrocarbon seep complex in northern Italy
    (Instytut Paleobiologii PAN, 2018-06-26) Kiel, Steffen ; Taviani, Marco
    Seven species of chemosymbiotic bivalves are described from the late Pliocene Stirone River hydrocarbon seep complex in northern Italy, including one new species and two in open nomenclature. The known species are the solemyid Acharax doderleini, the lucinids Lucinoma persolida and Megaxinus ellipticus, and the vesicomyid Isorropodon aff. perplexum; in open nomenclature we report two lucinids, including the largest species of Lucinoma known from the Italian Pliocene to date, and a strongly inflated, large Anodontia sp. The most abundant species at the Stirone seep complex is the lucinid Megaxinus stironensis sp. nov. This Pliocene seep fauna differs from that of the well-known Miocene “Calcari a Lucina” seep deposits by lacking large bathymodiolin mussels and vesicomyid clams; instead, the dominance of the lucinid Megaxinus stironensis gives this fauna a unique character. We speculate that at the Stirone seep complex, Megaxinus had occupied the ecological niche that Meganodontia occupied at the Miocene “Calcari a Lucina” seep sites in the Mediterranean basin, and that the dominance of Megaxinus could be a wide-spread feature of Pliocene chemosynthesis-based ecosystems in Mediterranean Pliocene.
  • Article
    Application of hyperspectral imaging to underwater habitat mapping, Southern Adriatic Sea
    (MDPI, 2019-05-16) Foglini, Federica ; Grande, Valentina ; Marchese, Fabio ; Bracchi, Valentina A. ; Prampolini, Mariacristina ; Angeletti, Lorenzo ; Castellan, Giorgio ; Chimienti, Giovanni ; Hansen, Ingrid M. ; Gudmundsen, Magne ; Meroni, Agostino N. ; Mercorella, Alessandra ; Vertino, Agostina ; Badalamenti, Fabio ; Corselli, Cesare ; Erdal, Ivar ; Martorelli, Eleonora ; Savini, Alessandra ; Taviani, Marco
    Hyperspectral imagers enable the collection of high-resolution spectral images exploitable for the supervised classification of habitats and objects of interest (OOI). Although this is a well-established technology for the study of subaerial environments, Ecotone AS has developed an underwater hyperspectral imager (UHI) system to explore the properties of the seafloor. The aim of the project is to evaluate the potential of this instrument for mapping and monitoring benthic habitats in shallow and deep-water environments. For the first time, we tested this system at two sites in the Southern Adriatic Sea (Mediterranean Sea): the cold-water coral (CWC) habitat in the Bari Canyon and the Coralligenous habitat off Brindisi. We created a spectral library for each site, considering the different substrates and the main OOI reaching, where possible, the lower taxonomic rank. We applied the spectral angle mapper (SAM) supervised classification to map the areal extent of the Coralligenous and to recognize the major CWC habitat-formers. Despite some technical problems, the first results demonstrate the suitability of the UHI camera for habitat mapping and seabed monitoring, through the achievement of quantifiable and repeatable classifications.
  • Article
    First ROV exploration of the Perth Canyon: Canyon setting, faunal observations, and anthropogenic impacts.
    (Frontiers Media, 2019-04-12) Trotter, Julie A. ; Pattiaratchi, Charitha ; Montagna, Paolo ; Taviani, Marco ; Falter, James L. ; Thresher, Ronald E. ; Hosie, Andrew ; Haig, David ; Foglini, Federica ; Hua, Quan ; McCulloch, Malcolm
    This study represents the first ROV-based exploration of the Perth Canyon, a prominent submarine valley system in the southeast Indian Ocean offshore Fremantle (Perth), Western Australia. This multi-disciplinary study characterizes the canyon topography, hydrography, anthropogenic impacts, and provides a general overview of the fauna and habitats encountered during the cruise. ROV surveys and sample collections, with a specific focus on deep-sea corals, were conducted at six sites extending from the head to the mouth of the canyon. Multi-beam maps of the canyon topography show near vertical cliff walls, scarps, and broad terraces. Biostratigraphic analyses of the canyon lithologies indicate Late Paleocene to Late Oligocene depositional ages within upper bathyal depths (200–700 m). The video footage has revealed a quiescent ‘fossil canyon’ system with sporadic, localized concentrations of mega- and macro-benthos (∼680–1,800 m), which include corals, sponges, molluscs, echinoderms, crustaceans, brachiopods, and worms, as well as plankton and nekton (fish species). Solitary (Desmophyllum dianthus, Caryophyllia sp., Vaughanella sp., and Polymyces sp.) and colonial (Solenosmilia variabilis) scleractinians were sporadically distributed along the walls and under overhangs within the canyon valleys and along its rim. Gorgonian, bamboo, and proteinaceous corals were present, with live Corallium often hosting a diverse community of organisms. Extensive coral graveyards, discovered at two disparate sites between ∼690–720 m and 1,560–1,790 m, comprise colonial (S. variabilis) and solitary (D. dianthus) scleractinians that flourished during the last ice age (∼18 ka to 33 ka BP). ROV sampling (674–1,815 m) spanned intermediate (Antarctic Intermediate Water) and deep waters (Upper Circumpolar Deep Water) with temperatures from ∼2.5 to 6°C. Seawater CTD profiles of these waters show consistent physical and chemical conditions at equivalent depths between dive sites. Their carbonate chemistry indicate supersaturation (Ωcalcite ∼ 1.3–2.2) with respect to calcite, but mild saturation to undersaturation (Ωaragonite ∼ 0.8–1.4) of aragonite; notably some scleractinians were found living below the aragonite saturation horizon (∼1,000 m). Seawater δ13C and nuclear bomb produced Δ14C compositions decrease in the upper canyon waters by up to ∼0.8‰ (<800 m) and 95‰ (<500 m), respectively, relative to measurements taken nearby in 1978, reflecting the ingress of anthropogenic carbon into upper intermediate waters.
  • Article
    The Gela Basin pockmark field in the strait of Sicily (Mediterranean Sea) : chemosymbiotic faunal and carbonate signatures of postglacial to modern cold seepage
    (Copernicus Publications on behalf of the European Geosciences Union, 2013-07-12) Taviani, Marco ; Angeletti, Lorenzo ; Ceregato, A. ; Foglini, F. ; Froglia, C. ; Trincardi, F.
    The geo-biological exploration of a pockmark field located at ca. 800 m below sea level in the Gela basin (Strait of Sicily, Central Mediterranean) provided a relatively diverse chemosymbiotic community and methane-imprinted carbonates. To date, this is the first occurrence of such a type of specialised deep-water cold-seep communities recorded from this key region, before documented in the Mediterranean as rather disjunct findings in its eastern and westernmost basins. The thiotrophic chemosymbiotic organisms recovered from this area include empty tubes of the vestimentiferan Lamellibrachia sp., loose and articulated shells of lucinids (Lucinoma kazani, Myrtea amorpha), vesicomyids (Isorropodon perplexum), and gastropods (Taranis moerchii). A callianassid decapod (Calliax sp.) was consistently found alive in large numbers in the pockmark mud. Their post-mortem calcified parts mixed with molluscs and subordinately miliolid foraminifers form a distinct type of skeletal assemblage. Carbonate concretions display δ13C values as low as −40‰ PDB suggesting the occurrence of light hydrocarbons in the seeping fluids. Since none of the truly chemosymbiotic organisms was found alive, although their skeletal parts appear at times very fresh, some specimens have been AMS-14C dated to shed light on the historical evolution of this site. Lamellibrachiav and Lucinoma are two of the most significant chemosymbiotic taxa reported from various Mediterranean cold seep sites (Alboran Sea and Eastern basin). Specimens from station MEDCOR78 (pockmark #1, Lat. 36°46´10.18" N, Long. 14°01´31.59" E, 815 m below sea level) provided ages of 11736 ± 636 yr cal BP (Lamellibrachia sp.), and 9609.5 ± 153.5 yr cal BP (L. kazani). One shell of M. amorpha in core MEDCOR81 (pockmark #6, Lat 36°45´38.89" N, Long 14°00´07.58" E, 822 m below sea level) provided a sub-modern age of 484 ± 54 yr cal BP. These ages document that fluid seepage at this pockmark site has been episodically sustaining thiotrophic macrobenthic communities since the end of the Younger Dryas stadial up to sub-recent times.
  • Article
    Diversity and distribution of prokaryotes within a shallow-water pockmark field
    (Frontiers Media, 2016-06-17) Giovannelli, Donato ; d'Errico, Giuseppe ; Fiorentino, Federica ; Fattorini, Daniele ; Regoli, Francesco ; Angeletti, Lorenzo ; Bakran-Petricioli, Tatjana ; Vetriani, Costantino ; Yucel, Mustafa ; Taviani, Marco ; Manini, Elena
    Pockmarks are crater-like depression on the seafloor associated with hydrocarbon ascent through muddy sediments in continental shelves around the world. In this study, we examine the diversity and distribution of benthic microbial communities at shallow-water pockmarks adjacent to the Middle Adriatic Ridge. We integrate microbial diversity data with characterization of local hydrocarbons concentrations and sediment geochemistry. Our results suggest these pockmarks are enriched in sedimentary hydrocarbons, and host a microbial community dominated by Bacteria, even in deeper sediment layers. Pockmark sediments showed higher prokaryotic abundance and biomass than surrounding sediments, potentially due to the increased availability of organic matter and higher concentrations of hydrocarbons linked to pockmark activity. Prokaryotic diversity analyses showed that the microbial communities of these shallow-water pockmarks are unique, and comprised phylotypes associated with the cycling of sulfur and nitrate compounds, as well as numerous know hydrocarbon degraders. Altogether, this study suggests that shallow-water pockmark habitats enhance the diversity of the benthic prokaryotic biosphere by providing specialized environmental niches.
  • Article
    Offshore Neopycnodonte oyster reefs in the Mediterranean Sea
    (MDPI, 2020-03-05) Angeletti, Lorenzo ; Taviani, Marco
    Oysters are important ecosystem engineers best known to produce large bioconstructions at shallow depth, whilst offshore deep-subtidal oyster reefs are less widely known. Oyster reefs engineered by Neopycnodonte cochlear (family Gryphaeidae) occur at various sites in the Mediterranean Sea, between 40 and 130 m water depths. Remotely Operated Vehicle surveys provide new insights on this rather neglected reef types with respect to their shape, dimensions and associated biodiversity. We suggest that these little contemplated reefs should be taken in due consideration for protection.
  • Article
    Seismic hazards implications of uplifted Pleistocene coral terraces in the Gulf of Aqaba
    (Nature Publishing Group, 2017-02-24) Bosworth, William ; Montagna, Paolo ; Pons-Branchu, Edwige ; Rasul, Najeeb ; Taviani, Marco
    The Gulf of Aqaba transform plate boundary is a source of destructive teleseismic earthquakes. Seismicity is concentrated in the central sub-basin and decreases to both the north and south. Although principally a strike-slip plate boundary, the faulted margins of the Gulf display largely dip-slip extensional movement and accompanying footwall uplift. We have constrained rates of this uplift by measurements of elevated Pleistocene coral terraces. In particular the terrace that formed during the last interglacial (~125 ka) is found discontinuously along the length of the Gulf at elevations of 3 to 26 m. Global sea level was ~7 m higher than today at 125 ka indicating net maximum tectonic uplift of ~19 m with an average rate of ~0.015 cm/yr. Uplift has been greatest adjacent to the central sub-basin and like the seismicity decreases to the north and south. We suggest that the present pattern of a seismically active central region linked to more aseismic areas in the north and south has therefore persisted for at least the past 125 kyr. Consequently the potential for future destructive earthquakes in the central Gulf is greater than in the sub-basins to the north and south.