Naslov
Marine radiocarbon reservoir age of the coralline rhodophyte alga Lithophyllum byssoides in the Mediterranean

Autori
Faivre, Sanja ; Bakran-Petricioli, Tatjana ; Barešić, Jadranka ; Borković, Damir ; Horvatić, Davor

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Radiocarbon and Diet 2017 2 : Book of abstracts / - Aarhus, 2017, 32-33

Skup
Radiocarbon and Diet 2017 2

Mjesto i datum
Århus, Danska, 20.06.2017. - 23.06.2017

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
coralline algae ; Lithophyllum byssoides ; marine radiocarbon reservoir age ; Mediterranean

Sažetak
Coralline algae are very important framework builders outside the coral-reef belt and therefore they could provide very important records on palaeoclimate and palaeoenvironment. This archive, even though recently underutilized, has the potential to fill the gap left by the spatially restricted occurrence of reef-building coral proxy archives. Moreover, algal rims created by Lithophyllum byssoides are very precise sea-level markers (±10cm) in the microtidal environment because the life range of the alga relates directly to the tide. This perfect relative sea-level marker is constrained by its marine radiocarbon reservoir age (MRE) which is not known. Highly accurate age determination is a principal procedure in the research of past global environmental changes, which can further allow a realistic prediction of changes in the future. In palaeo-sea-level research, the late Holocene is the most intensively studied period, which, due to its brevity, requires even more precision and accuracy. Previously, it was assumed that alga L. byssoides does not have any marine radiocarbon reservoir effect. This assumption was based on dating of living thalli. However, recently, researches have also corrected algal 14C data with global means. Working with very short time-scales (e.g. a period of 2 ka) we observed that young samples can’t be corrected with global means. Therefore, here we provide evidence for the algal MRE based on algal samples of known age obtained from the Natural History Museums in Paris, Vienna and Hamburg. The algae used for 14C dating were collected from AD 1858 to 1913 and represent the pre-bomb period. 8 samples are from the Mediterranean while 1 sample is from the Atlantic. We applied radiocarbon dating of marine material with a known calendar date of death of the organism. This approach enables a comparison of contemporaneous atmospheric and marine radiocarbon ages. The deficiency in 14C content of the measured marine sample relative to the global atmospheric calibration curve is then used to calculate the "apparent age" of the material. The weighted mean was calculated using only the Mediterranean samples even though the use of the Atlantic sample would not have changed the final result. We also used palaeo data from 9 Eastern Adriatic algal rims from which we obtained more than 100 algal radiocarbon and stable isotope (δ180 and δ13C) records. Based on those records we provide several lines of evidence that the alga which lives in the intertidal zone has a lower marine radiocarbon reservoir age than the mean surface water MRE, while, on the other hand, shells (mytilid bivalves) which usually live in the biogenic rims have higher reservoir ages than global means. This research was supported by the Croatian Science Foundation (project no. HRZZ-IP-11- 2013-1623, Reconstruction of the Quaternary environment in Croatia using isotope methods – REQUENCRIM) and by the University of Zagreb Supports for 2013 (no. 4.1.1.28), 2014 (no. IP2.4) and 2015 (no. IP003). We would also like to express our gratitude to the Muséum National d’Histoire Naturelle in Paris, especially to Bruno de Reviers, for providing algal samples from its collections for this research, as well as to Christophe Morhange for helping us in that regard. We also thank the Universität Hamburg, Biozentrum Klein Flottbek und Botanischer Garten, Dr. Matthias Schultz (curator at Herbarium Hamburgense) as well as the Naturhistorisches Museum, Wien, Dr. Anton Igersheim (Curator of the Cryptogamic Collection) both of which kindly provided samples without which this study could not be effectuated.

Izvorni jezik
Engleski

Znanstvena područja
Geografija

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