The Giant Marine Gastropod Campanile Giganteum (Lamarck, 1804) as a High‐Resolution Archive of Seasonality in the Eocene Greenhouse World

Abstract

Giant gastropods are among the largest mollusks in the fossil record, but their potential as paleoseasonality archives has received little attention. Here, we combine stable isotope and trace element analyses with microscopic observations and growth modeling on shells of two species of the gastropod genus Campanile: the extinct Campanile giganteum from Lutetian (~45 Ma) deposits in the Paris Basin (France), the longest gastropod known from the fossil record, and its modern relative Campanile symbolicum from southwestern Australia. The C. giganteum shells contain original aragonite and have pristine nacre in their apertures. We show that these gastropods attained growth rates exceeding 600 mm/year along their helix, depositing over 300 cm 3 aragonite per year. High growth rates and excellent preservation make C. giganteum excellent archives for reconstructing environmental change at high (potentially daily) temporal resolution, while providing enough material for methods such as clumped isotope analysis. Growth models show that Campanile gastropods grew nearly year-round, albeit slower in winter. Stable oxygen isotope ratios in modern C. symbolicum faithfully record a seasonal variability of 18-25°C in sea surface temperature, only failing to record the coolest winter temperatures (down to~16°C). Similarly, C. giganteum specimens likely record a nearly complete seasonal temperature range. Assuming constant sea water isotope composition, their oxygen isotope seasonality of up to 2.5‰ would translate to a Lutetian temperature range of 21-32°C in the Paris Basin. We hypothesize that these high and seasonally variable temperatures formed the breeding ground for the Lutetian shallow marine biodiversity hotspot in the Paris Basin.

Shell chemistry of the boreal Campanian bivalve <i>Rastellum diluvianum</i> (Linnaeus, 1767) reveals temperature seasonality, growth rates and life cycle of an extinct Cretaceous oyster

“…While periods of growth cessation can occur (especially in high latitudes; Ullmann et al, 2010) and the true mechanisms of shell deposition at a very high (e.g., daily) temporal resolution are poorly constrained (see de Winter et al, 2020a, and references therein), in practice incremental shell deposition allows reconstructions of changes down to sub-daily timescales given the right sampling techniques (Schöne et al, 2005;Sano et al, 2012;Warter et al, 2018;de Winter et al, 2020a). Examples of chemical proxies used in such sclerochronology studies include stable carbon and oxygen isotope ratios and trace element ratios (e.g., Gillikin et al, 2006;McConnaughey and Gillikin, 2008;Schöne et al, 2011;de Winter et al, 2017ade Winter et al, , 2018.…”

“…The effect on shell composition and preservation of changes in microstructure and the amount of organic matrix present in different shell layers introduce uncertainty as to which parts of the shells are well-suited for reconstruction purposes (Carriker et al, 1991;Kawaguchi et al, 1993;Dalbeck et al, 2006;Schöne et al, 2010. The key to disentangling vital effects from recorded environmental changes lies in the application of multiple proxies and techniques on the same bivalve shells (the "multi-proxy approach"; e.g., Ullmann et al, 2013;de Winter et al, 2017ade Winter et al, , 2018 and basing reconstructions on more than one shell (Ivany, 2012).…”

“…In this study, we present a detailed, multi-proxy comparison of the growth and chemistry of well-preserved fossil shells of the thick-shelled oyster Rastellum diluvianum (Linnaeus, 1767) recovered from the Ivö Klack locality on the northern edge of the Kristianstad Basin. We combine stable isotope proxies, conventional in sclerochronological studies (δ 13 C and δ 18 O; e.g., Goodwin et al, 2001;Steuber et al, 2005), with less well established trace element proxies (Mg/Ca, Sr/Ca, Mg/Li and Sr/Li; e.g., Bryan and Marchitto, 2008;Schöne et al, 2011;Füllenbach et al, 2015;Dellinger et al, 2018) and growth modeling based on δ 18 O seasonality (Judd et al, 2018) in an attempt to disentangle the effects of growth rate, reproductive cycle and environmental change on shell chemistry. The data gathered in this study allow a detailed discussion on seasonal changes in temperature and water chemistry in the coastal waters of the Kristianstad Basin in the late early Campanian as well as on the life cycle of R. diluvianum and its response to seasonal changes in its environment.…”

“…Exposure times of the X-ray beam per sampling position in mapping mode (1 ms per pixel) are too short to gain an adequate signal-to-noise ratio for pixel-by-pixel quantification of elemental concentrations. Instead, processing of entire map surfaces using the Bruker ESPRIT™ software allows semi-quantitative elemental abundance maps to be created of the sample surface based on a mapping of the count rate in "Regions of Interest" of elements (see de Winter and Claeys, 2016;de Winter et al, 2017b;Fig. 3).…”

Optimizing sampling strategies in high-resolution paleoclimate records

“…CC BY 4.0 License. marked as promising archives for such variability, while other fast-growing archives such as Acropora corals remain to be explored (Bak et al, 2009;Strauss et al, 2014;de Winter et al, 2020c). It must be noted that models for the timing of carbonate deposition in accretionary carbonate archives at the sub-daily scale are highly uncertain and that this may complicate the use of the binning approach (see 5.1.3), in which case optimization may be more appropriate.…”