Growth-increment characteristics and isotopic (?18O) temperature record of sub-thermocline Aequipecten opercularis (Mollusca:Bivalvia): evidence from modern Adriatic forms and an application to early Pliocene examples from eastern England

The shell ?18O of young modern Aequipecten opercularis from the southern North Sea provides an essentially faithful record seasonal variation in seafloor temperature. In this well-mixed setting, A. also serves as a proxy for surface Individuals less agitated (e.g. deeper) settings warm climate would not be expected to full range temperature because thermal stratification summer. Such circumstances have been invoked explain cool isotopic summer temperatures early Pliocene eastern England. Support sub-thermocline setting derives high-amplitude microgrowth-increment size, which resembles pattern Mediterranean Sea. Here, we present isotope and increment profiles further individuals, live-collected location Adriatic provide modelled values ?18O. We data supra-thermocline shells English Channel French coast. great majority show winter are generally quite close expectation. However, relatively conditions 2015 recorded, most cases due break growth, perhaps caused by hypoxia. subdued yield local directly measured values. therefore fairly good ambient (if always below thermocline) their hydrographic can determined data. Early examples England interpreted having lived thermocline, with higher than now adjacent