Shell growth and oxygen isotopes in the topshell Osilinus turbinatus: resolving past inshore sea surface temperatures

Mesolithic shellfish exploitation in SW Italy: seasonal evidence from the oxygen isotopic composition of Osilinus turbinatus shells

“…It inhabits the biotope exposed to high wave energy with low salinity oscillations (Torelli, 1982;Schifano and Censi, 1983;Mannino et al, 2008). Regional studies have attested that O. turbinatus grows generally throughout the year (Regis, 1972;Schifano, 1983;Valli et al, 2003;Mannino et al, 2008).…”

“…However growth rates exhibit strong variability in SW Italy, mostly related to seasonal environmental conditions and age (e.g. Schifano and Censi, 1983;Mannino et al, 2008). In NW Sicily maximum growths are recorded during autumn-winter, whereas minimum growths are observed in spring-summer, providing a mean annual growth rate ranging from ca.…”

“…Schö ne et al, 2007 and references therein), shell growth rate decrease with ontogenetic age (Mannino et al, 2008). (Schifano and Censi, 1983;Mannino et al, 2008), thus emphasizing their potential suitability for the study of seasonal shellfish exploitation in prehistoric sites (Mannino et al, 2007 During each collection period, surface sea water temperature was measured. Mean monthly sea surface salinity (SSS) for this area was obtained from the European Project ''Mediterranean ocean forecasting system: toward environmental predictions (MFSTEP)'' (http://www.bo.ingv.it/mfstep).…”

“…Adult specimens may be represented by shells ranging from 15 to 38 mm of diameter (e.g. Poppe and Goto, 1991), and shell growth checks might not provide reliable markers of ontogenic age (Mannino et al, 2008). Since medium shells provide sufficient calcium carbonate relative to the last growth year to be sampled for seasonal studies (Mannino et al, 2007), medium shells of almost similar size were selected (20-24 mm width).…”

“…Both modern and archaeological specimens were immersed in 30% of H 2 O 2 for 48 h, rinsed with de-ionised water, cleaned in an ultrasonic bath and dried in an oven at 35 C for 24 h. O. turbinatus secretes an entire inner aragonite shell (Schifano and Censi, 1983;Mannino et al, 2008). The shell structure was investigated using Xray diffraction (XRD) and scanning electron microscopy (SEM).…”