0000000000793631
AUTHOR
Soraya Marali
Ba/Ca ratios in shells of Arctica islandica —Potential environmental proxy and crossdating tool
Abstract Ba/Ca shell time-series of marine bivalves typically show flat background levels which are interrupted by erratic sharp peaks. Evidence from the literature indicates that background Ba/Ca shell ratios broadly reflect salinity conditions. However, the causes for the Ba/Ca shell peaks are still controversial and widely debated although many researchers link these changes to primary productivity, freshwater input or spawning events. The most striking feature is that the Ba/Ca shell peaks are highly synchronous in contemporaneous specimens from the same population. For the first time, we studied Ba/Ca shell in mature and ontogenetically old (up to 251 year-old) specimens of the long-li…
Investigating the Local Reservoir Age and Stable Isotopes of Shells from Southeast Arabia
AbstractWe recently started a systematic approach to determine the reservoir age in southeast Arabia and its dependence on mollusk species and their environment. This part of the study concentrates on local reservoir age and stable isotopes of the lagoonal species Terebralia palustris and Anadara uropigimelana at Khor Kalba, Oman Sea. Environmental and nutritive influences on mollusks are reflected in the radiocarbon and stable isotope signal. We found a local reservoir age of A. uropigimelana of about 940 yr and that of T. palustris as 800 yr. Sclerochronological analyses yielded information about seasonality of growth and death in A. uropigimelana. The modern shell of Periglypta reticulat…
Oceanographic control on shell growth of Arctica islandica (Bivalvia) in surface waters of Northeast Iceland — Implications for paleoclimate reconstructions
Absolutely dated, annually resolved sea surface temperature records from middle to higher latitudes covering long time intervals are crucial to better understand the climate system. Such data can potentially be obtained from variations in shell growth of long-lived bivalves such as Arctica islandica. This study presents the first statistically robust 178-yr long composite chronology (covering 1835–2012) based on sixteen live-collected and subfossil specimens of A. islandica from unpolluted, shallow waters of Northeast Iceland. Between 1875 and 1996, up to 43% of the variation in annual shell growth was explained by SST during February to September. Faster growth occurred when temperatures w…
Reproducibility of trace element time-series (Na/Ca, Mg/Ca, Mn/Ca, Sr/Ca, and Ba/Ca) within and between specimens of the bivalve Arctica islandica – A LA-ICP-MS line scan study
Abstract Trace element time-series in bivalve mollusk shells and other (biogenic) materials can potentially serve as environmental proxies. Yet, the applicability of element-to-calcium ratios is often challenging, because non-environmental factors such as vital effects distort or mask environmental signals. If a trace element time-series is driven by an environmental factor, it should be reproducible within and between coeval specimens of the same species. In the present study, we tested whether time-series of trace element-to-calcium ratios can be reproduced within and between coeval specimens of the bivalve Arctica islandica and thus whether an external signal is encoded in the temporal v…
History of bioavailable lead and iron in the Greater North Sea and Iceland during the last millennium – A bivalve sclerochronological reconstruction
We present the first annually resolved record of biologically available Pb and Fe in the Greater North Sea and Iceland during 1040-2004 AD based on shells of the long-lived marine bivalve Arctica islandica. The iron content in pre-industrial shells from the North Sea largely remained below the detection limit. Only since 1830, shell Fe levels rose gradually reflecting the combined effect of increased terrestrial runoff of iron-bearing sediments and eutrophication. Although the lead gasoline peak of the 20th century was well recorded by the shells, bivalves that lived during the medieval heyday of metallurgy showed four-fold higher shell Pb levels than modern specimens. Presumably, pre-indus…