Seasonality in sea surface temperatures from δ¹⁸O inCladocora caespitosa: modern Adriatic to late Pleistocene, Gulf of Corinth

Abstract

High‐resolution stable isotope analysis of coral skeletons is an established method to help reconstruct seawater growth temperatures for palaeoenvironmental reconstructions. Here we investigated the temperate, colonial, Mediterranean scleractinian coral Cladocora caespitosa. We first studied modern Adriatic corals from Mljet (Croatia) where growth temperatures were known. A clear sinusoidal cyclicity is present in the δ18O of the modern coral skeletons with average cycle minima ∼−3.3‰ and average maxima ∼−1.6‰. Cyclicity approximately matches the number of seasonal growth band pairs in each sample, implying a genetic link between δ18O cyclicity and factors that determine seasonal growth band development, here mainly water temperature. A derived and calibrated species‐specific δ18O–temperature relationship was then used to reconstruct growth temperatures from fossil C. caespitosa. This was applied to well‐preserved material collected from late Pleistocene deposits (MIS 1, 5 and 7) around the Gulf of Corinth, Greece. Clear seasonal δ18O signals are seen in all the fossil samples. MIS 5e was the warmest period studied with a lower than modern seasonal temperature range. The Early to mid‐Holocene probably experienced the lowest temperatures while conditions in MIS 7a/c were probably the wettest with most freshwater input into the Gulf.

Are landscapes buffered to high-frequency climate change? A comparison of sediment fluxes and depositional volumes in the Corinth Rift, central Greece, over the past 130 k.y.

“…The mean temperature for the catchments yields a value of 14.5 °C for the Holocene (Table 1). This tempera ture is ~1.5 °C lower than Corinth SSTs (Royle et al, 2015), so we investigated the possibility that Holocene temperatures could be ±10% from the World-Clim values. Annual catchment precipitation means derived from WorldClim data sets range between 544 and 880 mm/yr (Table 1); we similarly considered a ±10% variation from these precipitation values in our model.…”

“…Currently, the Gulf of Corinth experiences a warm temperate climate with hot dry summers (Kottek et al, 2006). Holocene mean seasurface temperature (SST), based on analysis of sclerac tinian coral Cladocora caespitosa, is ~16 °C (Royle et al, 2015). Weather station records for 1950-2000, such as the WorldClim precipitation and temperature data sets (see Hijmans et al, 2005 for full study), suggest a mean temperature range of 11 °C to 17.4 °C, with a yearly mean of 14.5 °C for catchments in this study.…”