Search results for "Glycymeris"
showing 8 items of 8 documents
Late Holocene seasonal temperature variability of the western Scottish shelf (St Kilda) recorded in fossil shells of the bivalve Glycymeris glycymeris
2021
Abstract The North Atlantic Ocean and adjacent shelf seas play a crucial role in global climate. To better constrain long-term natural variability and marine-terrestrial linkages in this region, a network of highly resolved marine archives from the open ocean and continental shelves is needed. In recent decades, bivalve sclerochronology has emerged as a field providing such records from the mid- to high latitudes. In May 2014, dead valves and young live specimens of the bivalve Glycymeris glycymeris were collected at St Kilda, Scotland. A floating chronology spanning 187 years was constructed with fossil shells and radiocarbon dated to 3910–3340 cal yr before present (BP), with a probabilit…
Drivers of shell growth of the bivalve, Callista chione (L. 1758) - Combined it environmental and biological factors
2018
WOS:000426027100014; Seasonal shell growth patterns were analyzed using the stable oxygen and carbon isotope values of live-collected specimens of the bivalve Callista chione from two sites in the Adriatic Sea (Pag and Cetina, Croatia). Micromilling was performed on the shell surface of three shells per site and shell oxygen isotopes of the powder samples were measured. The timing and rate of seasonal shell growth was determined by aligning the delta O-18(shell)-derived temperatures so that the best fit was achieved with the instrumental temperature curve. According to the data, shells grew only at very low rates or not at all during the winter months, i.e., between January and March. Shell…
Morphological variations of crossed-lamellar ultrastructures of Glycymeris bimaculata (Bivalvia) serve as a marine temperature proxy
2020
Abstract Bivalve shells are among the most promising archives for high-resolution seawater temperature reconstructions. However, despite major research advances in bivalve sclerochronology over the past decades, estimating water temperature from shells remains a challenging task. This is largely because the most frequently used and widely accepted temperature proxy in bivalves, i.e., the shell oxygen isotope (δ18Oshell) value, also requires knowledge of changes in δ18O of the water (δ18Owater) in which the bivalve lived, which is rarely available for ancient environments. According to a few recent studies, the size and shape of individual biomineral units (BMUs) of the shell ultrastructure …
Spatial variations in Ba/Cashell fingerprints of Glycymeris pilosa along the eastern Adriatic Sea
2020
Abstract The long living Glycymeris pilosa bivalve is an interesting target species for the sclerochronological research in the Mediterranean Sea. In this study, Ba/Cashell and Mg/Cashell variations were studied along the coast of the eastern Adriatic Sea. Specimens were collected alive by SCUBA and skin diving during several occasions in 2014, 2015 and 2016 from five sites including Pag, Pasman Channel, Cetina, Živogosce and Drace. Element-to-Cashell ratios were measured by LA-ICP-MS in line scan mode in three specimens of each site, ranging in age from 7 to 21. In addition, chemical analysis was conducted on three ontogenetically older specimens (68-97 years-old) from Drace. Mg/Cashell an…
Glycymeris pilosa (Bivalvia) - A high-potential geochemical archive of the environmental variability in the Adriatic Sea.
2019
Due to its outstanding longevity (decades), the shallow-water bivalve Glycmeris pilosa represents a prime target for sclerochronological research in the Mediterranean Sea. In the present study, we analyzed the microgrowth patterns and the stable carbon (δ13Cshell) and oxygen (δ18Oshell) isotopes of the outer shell layer of live-collected G. pilosa specimens from four different sites along the Croatian coast, middle Adriatic Sea. Combined analysis of shell growth patterns and temporally aligned δ18Oshell data indicated that the main growing season lasts from April to December, with fastest growth rates occurring during July and August when seawater temperatures exceeded 22 °C. Slow growth in…
Structural commonalities and deviations in the hierarchical organization of crossed-lamellar shells: A case study on the shell of the bivalve Glycyme…
2016
11 pages; International audience; The structural organization of the palliostracum—the dominant part of the shell which is formed by the mantle cells—of Glycymeris glycymeris (Linné 1758) is comprised of five hierarchical levels with pronounced structural commonalities and deviations from other crossed-lamellar shells. The hierarchical level known as second order lamellae, present within other crossed-lamellar shells, is absent highlighting a short-coming of the currently used nomenclature. On the mesoscale, secondary microtubules penetrate the palliostracum and serve as crack arrestors. Moreover, the growth lamellae follow bent trajectories possibly impacting crack propagation, crack defle…
A 45-year sub-annual reconstruction of seawater temperature in the Bay of Brest, France, using the shell oxygen isotope composition of the bivalve Gl…
2020
A reconstruction of sea surface temperature (SST) spanning 45 years (1966–2011) was developed from δ18O obtained from the aragonitic shells of Glycymeris glycymeris, collected from the Bay of Brest, France. Bivalve sampling was undertaken monthly between 2014 and 2015 using a dredge. In total, 401 live specimens and 243 articulated paired valves from dead specimens were collected, of which 24 individuals were used to reconstruct SST. Temperatures determined using the palaeotemperature equation of Royer et al. compared well with observed SST during the growing season between 1998 and 2010 (Pearson’s correlation: p = 0.002, r = 0.760). Furthermore, a significant negative correlation was foun…
The bivalve <i>Glycymeris planicostalis</i> as a high-resolution paleoclimate archive for the Rupelian (Early Oligocene) …
2015
Abstract. Current global warming is likely to result in a unipolar glaciated world with unpredictable repercussions on atmospheric and oceanic circulation patterns. These changes are expected to affect seasonal extremes and the year-to-year variability of seasonality. To better constrain the mode and tempo of the anticipated changes, climatologists require ultra-high-resolution proxy data of time intervals in the past, e.g., the Oligocene, during which boundary conditions were similar to those predicted for the near future. In the present paper, we assess whether such information can be obtained from shells of the long-lived bivalve mollusk Glycymeris planicostalis from the late Rupelian of…