Temperature and hydrological variations during the late-glacial in the Central Mediterranean: Application of the novel ostracod-clumped isotope thermometer

The Ostracod Clumped‐Isotope Thermometer: A Novel Tool to Accurately Quantify Continental Climate Changes

“…). Furthermore, recent shells (last 1 kyr) of the two species C. torosa and C. angulata both recorded temperatures that overlap with the ones measured today at Lake Trasimeno during the respective shell precipitation season (C. torosa Δ 47 T is 22.5 ± 2.3°C -warm season average temperature is 21.2°C today; C. angulata Δ 47 T is 8.0 ± 2.9°C -cold season average temperature is 8.2°C today), excluding a vital effect in their Δ 47 signal(Marchegiano et al, 2024;Yue et …”

“…To convert the Δ 47 fossil ostracod value into temperatures, Song et al (2022) and Yue et al (2022) relied on the dolomite calibration from Bonifacie et al (2017) and the travertine calibration from Kele et al (2015) recalculated in Bernasconi et al (2018), respectively. Instead, Marchegiano et al (2024) used the unified calibration of Anderson et al (2021). The Δ 47 analyses conducted on living ostracods that formed their shells under precisely known temperatures make it possible to select the most suitable calibration.…”

“…To determine the Δ 47 -T relationship for ostracod shells, clumped-isotopes were measured on four species that precipitated their shells at three different temperatures (4 ± 0.8°C, 10.1 ± 2°C and 23 ± 0.5°C). The two datapoints from Marchegiano et al (2024), obtained from recent shells (last 1kyr) of two other different species living today at Lake Trasimeno (central Italy) (i.e., C. torosa Δ 47 T of 22.5 ± 2.3°C and C. angulata Δ 47 T is 8.0 ± 2.9°C) at 21.2 ± 4°C (average warmer season temperatures) and 8.2 ± 2°C (average cold season temperatures) (World Lake Database, 2023), were also included (Table 1 and Figure 1). All the measured ostracod samples fall within the 95% confidence interval of the regression line of Anderson et al (2021): b) Ostracod clumped-isotope data against precipitated temperatures compared with clumped-isotope data from marine biogenic carbonate and continental slow grown calcite speleothems (De Winter et al, 2022;Fiebig et al, 2021;Huyghe et al, 2022;Meinicke et al, 2021;Peral et al, 2022) and the calibration from Daëron and Vermeesch (2023).…”

“…Ostracods record temperatures that represent a snapshot of the conditions existing when they precipitate their shells instead of mean annual average temperature, such as mollusks and inorganic carbonate. Marchegiano et al (2024) demonstrated that by combining paleontological (i.e., species identification), biological (i.e., calcification season), and geochemical (i.e., ∆ 47 technique and δ 18 O) information, it is possible to reconstruct past seasonal temperature and hydrological conditions. Because mean annual temperature and rainfall amount can be significantly biased by seasonality, it is of primary importance to disentangle these parameters.…”

“…In terrestrial environments, the ∆ 47 paleothermometer has mainly been applied on paleosol (e.g., Kelson et al., 2020; Passey et al., 2010; Quade et al., 2013) and speleothems (e.g., Affek et al., 2008; Daëron et al., 2011; Fernandez et al., 2023; Kluge & Affek, 2012; Nehme et al., 2023). In lacustrine records, the ∆ 47 technique was used on inorganic carbonates (e.g., Hudson et al., 2017; Huntington et al., 2010; Katz et al., 2023) and molluscs (e.g., Dong et al., 2021; Grauel et al., 2016; Tobin et al., 2014; Wang et al., 2016; Zaarur et al., 2011) and was only recently applied to ostracods to reconstruct paleoaltitude and paleoclimate (Marchegiano et al., 2024; Song et al., 2022; Yue et al., 2022).…”