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Radiocarbon reservoir ages in the Eastern Adriatic sea based on recent and pre-bomb marine organisms from the intertidal zone and shallow sea

In order to provide more precision and better accuracy of sea-level reconstruction for the last two millennia we started to use bio-constructions along the rocky coast of the eastern Adriatic. Fossil bio-constructions have proven to be precise sea-level indicators in microtidal environments. Rock-building elements such as the coralline rhodophyte Lithophyllum byssoides may under favourable conditions build up reef like bioconstructions of variable morphology that grow out from steep rocky surfaces slightly over mean sea-level. We sampled and analysed Lithophyllum rims at few sites along the eastern Adriatic coast. Lithophyllum and shells found inside the rims were dated using 14C analyses (LSC and AMS). The 14C reservoir effect may have an important influence to the final 14C results. Previous investigations of the reservoir ages of marine species along the Adriatic Sea were performed only on a few samples of infralittoral organisms from pre-bomb period. Analyses of the molluscs samples from other parts of the Mediterranean pointed that there might be a certain variation between molluscs from the same species, same year and same environment. Moreover, large variation that researchers found between ΔR values might indicate that reservoir ages of molluscs from intertidal behave differently than from molluscs from infralittoral or from deeper waters. It is clear that the better understanding of the reservoir age of organisms living in the intertidal zone is necessary. Consequently, here we present our research in which we try to answer some of the important questions: Is red coralline alga Lithophyllum byssoides affected by the reservoir effect? Do molluscs shells from the intertidal zone and shallow water show different reservoir ages compared to reservoir age usually used for the Mediterranean? Since no samples of Lithophyllum byssoides were collected and preserved before 1950 we used molluscs and other algae that live in the intertidal zone and shallow sea (infralittoral zone). The marine organisms for our research were obtained from the collections of the Natural History Museums in Rijeka and Zagreb, the National Museum in Zadar and from the Natural History Museum and the Zoo in Split. The molluscs and algae used for 14C dating were collected before 1950 and represent pre-bomb period.

radiocarbon reservoir age ; pre-bomb samples ; Adriatic sea

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