Search results for "Foraminifera"

Climatic variability and anthropogenic signatures in the Gulf of Salerno (southern-eastern Tyrrhenian Sea) during the last half-millennium

2012

Ba/Ca evolution in water masses of the Mediterranean late Neogene

2008

[1] A Mediterranean composite sedimentary record was analyzed for Ba/Ca ratios on carbonate shells of Orbulina universa planktonic foraminifer (Ba/Ca)carb providing the opportunity to study and assess the extent of freshwater inputs on the basin and possible impacts on its dynamics during the Tortonian to Recent period. A number of scanning electron microscope analyses and auxiliary trace element measurements (Mn, Sr, and Mg), obtained from the same samples, exclude important diagenetic effects on the studied biogenic carbonates and corroborate the reliability of (Ba/Ca)carb ratios in foraminifera calcite as indicators of seawater source components during the studied interval. A long-term t…

Distribution and ecology of the Globigerinoides ruber — Globigerinoides elongatus morphotypes in the Azores region during the late Pleistocene-Holoce…

2018

Abstract Globigerinoides ruber is the dominant taxon in the North Atlantic Subtropical Gyre, nowadays limited to the north by the Azores Current. It is highly sensitive to recent and late Pleistocene Azores Front Current System variability. In this study, we analyse the distribution of five individual morphotypes of the G. ruber – G. elongatus plexus (G. ruber s.s., G. ruber cyclostoma type, G. elongatus, G. elongatus cf.1, G. elongatus pyramidical type) and G. ruber kummerform gr. in a core (ATA13-OF-KT1) collected southwest of the Azores islands and located in a strategical position near the present-day boundary of the Subtropical Gyre/Azores Front Current System (STG/AFCS). Micropaleonto…

Anthropogenic impact and environmental evolution of the last 55 years of the Gulf of Palermo (Sicily, Italy)

2009

THE EFFECT OF HEAVY METALS ON BENTHIC FORAMINIFERA IN THE GULF OF GELA (SICILIAN CHANNEL)

2011

Benthic foraminifera are very sensitive to oceanographic parameter variations, to which they rapidly response through changes in the abundance and/or richness of their associations and in morphological variations of their shell. Many studies have used benthic foraminifera as bioindicators. We investigated recent benthic foraminiferal assemblages in the Gulf of Gela (Sicilian Channel, Mediterranean Sea), examining their relative abundance, specific richness and morphological abnormalities, to highlight a possible correlation with oceanographic features and the concentration of heavy metals in sediments. Sediment was sampled in summer 2006 using box corers in four stations at increasing dista…

Early Paleocene Paleoceanography and Export Productivity in the Chicxulub Crater

2021

The Chicxulub impact caused a crash in productivity in the world''s oceans which contributed to the extinction of ~75% of marine species. In the immediate aftermath of the extinction, export productivity was locally highly variable, with some sites, including the Chicxulub crater, recording elevated export production. The long-term transition back to more stable export productivity regimes has been poorly documented. Here, we present elemental abundances, foraminifer and calcareous nannoplankton assemblage counts, total organic carbon, and bulk carbonate carbon isotope data from the Chicxulub crater to reconstruct changes in export productivity during the first 3 Myr of the Paleocene. We sh…

Sella, A NEW NAME FOR THE GENUS Linaresia EL KADIRI, 1992 (NASSELLARIA, RADIOLARIA) PREOCCUPIED BY COPEPOD CRUSTACEANS (LAMIPPIDAE, MAXILLOPODA)

2021

The aim of this short note is to create a new name of this genus since the original name Linaresia proved to pre-exist in the paleontological literature ( Linaresia de Zulueta, 1908, Family Lamippidae, Copepod crustaceans, and Linaresia Gonzalez-Donoso, 1968, Family Gavelinellidae, Agglutinated Foraminifera). The new name created for the above mentioned radiolarians is: Sella . This name derives from an arbitrary combination of letters (International Code of Zoological Nomenclature). The type species of Sella is S. beniderkoulensis by original designation (El Kadiri, 1992).

Late Quaternary high uplift rates in northeastern Sicily: evidence from calcareous nannofossils and benthic and planktonic foraminifera

2011

The northeastern part of Sicily is characterized by intense seismic activity. Several systems of faults have been recognized in Pliocene and Pleistocene sediments in the area and, in fact, estimates of uplift rates are among the highest recorded in Sicily and south Italy. We examined calcareous nannofossil and benthic and planktonic foraminifera assemblages from pelitic sediments of the Contrada Zura section (Barcellona Pozzo di Gotto Basin, Furnari village, Messina). The occurrence of Emiliania huxleyi, a coccolithophore species which appeared in the oceanic record about 270,000 years ago, is witness to the uniqueness of this outcrop, while the planktonic/benthic foraminifera ratio indicat…

Orbitally induced limestone/marlstone rhythms in the Albian—Cenomanian Cismon section (Venetian region, northern Italy): Sedimentology, calcareous an…

1996

Abstract A multidisciplinary study of the upper Albian—Cenomanian portion of the Cismon section (Venetian region, northern Italy) was undertaken in order to characterize the cyclic alternations of carbonate-rich and carbonate-poor layers and to investigate their possible origin and cyclic patterns. Limestone semicouplets are characterized by abundant radiolarians and micarbs (micron-sized calcitic fragments), common planktonic foraminifera, strong bioturbation, good oxygenation as expressed by the Mn* and V/(V+Ni) parameters, high Si/Al ratio, low K/Al, in the absence of pyrite and organic matter. The marlstone semicouplets are, on the contrary, frequently laminated, rich in pyrite and orga…

Assessing the effect of chromium pollution on benthic foraminiferal community: morphological vs. environmental metabarcoding approaches

The purpose of this experimental study is to assess the impact of different concentrations of chromium (Cr) through time on the diversity of cultured benthic foraminifera combining two morphological approaches for the identification of living specimens that are Rose Bengal (RB) staining and CellTracker Green (CTG) labelling as well as environmental DNA and RNA metabarcoding. Seven tanks/aquaria with different concentrations of Cr in water, namely 100 ppt, 1 ppb, 10 ppb, 100 ppb, 1 ppm and 10 ppm plus the control were used. A mesocosm was extracted from each tank at pre-established time (1 week, 2 weeks, 4 weeks 6 weeks and 8 weeks). Morphological analyses produced 6 datasets based on staini…