scholarly journals First absolute seasonal temperature estimates for greenhouse climate from clumped isotopes in bivalve shells

2020 ◽  
Author(s):  
Niels de Winter ◽  
Inigo Müller ◽  
Ilja Kocken ◽  
Nicolas Thibault ◽  
Clemens Vinzenz Ullmann ◽  
...  
Keyword(s):  
Seasonal Variability ◽  
Climate Model ◽  
Sea Water ◽  
Isotope Composition ◽  
Seasonal Temperature ◽  
Deep Time ◽  
Temperature Reconstructions ◽  
Climate Model Simulations ◽  
Clumped Isotope ◽  
Bivalve Shells

Abstract The seasonal variability of sea surface temperatures plays a fundamental role in climate dynamics and species distribution. As such, it is essential to better understand seasonal variability in warm climates of the past. Previous reconstructions of seasonality in deep time are relatively unconstrained, relying on unsupported assumptions such as estimates of seawater composition and negligible seasonal bias. This work presents the first absolute seasonal temperature reconstructions based on clumped isotope measurements in bivalve shells which, critically, do not rely on these assumptions. Our new approach reconstructs highly precise mid-latitude (~50°N) monthly temperatures from individual oyster and rudist shells of the Campanian (78 million years ago) greenhouse period (15—27 °C seasonal range). Our analysis demonstrates that seasonal bias and previous assumptions about sea water oxygen isotope composition can lead to highly inaccurate temperature reconstructions, distorting our understanding of the behavior of greenhouse climates and our ability to model them. Our results agree remarkably well with fully coupled climate model simulations showing greenhouse climates outside the tropics were warmer with higher seasonality than previously thought.

scholarly journals First absolute seasonal temperature estimates for greenhouse climate from clumped isotopes in bivalve shells

2021 ◽  
Author(s):  
Niels de Winter ◽  
Inigo Müller ◽  
Ilja Kocken ◽  
Nicolas Thibault ◽  
Clemens Ullmann ◽  
...  
Keyword(s):  
Seasonal Variability ◽  
Climate Model ◽  
Sea Water ◽  
Isotope Composition ◽  
Seasonal Temperature ◽  
Deep Time ◽  
Temperature Reconstructions ◽  
Climate Model Simulations ◽  
Clumped Isotope ◽  
Bivalve Shells

Abstract Seasonal variability in sea surface temperatures plays a fundamental role in climate dynamics and species distribution. As such, it is essential to better understand seasonal variability in climates of the past. Previous reconstructions of seasonality in deep time are poorly constrained, relying on controversial assumptions such as estimates of seawater composition and neglect seasonal bias. This work presents the first absolute seasonal temperature reconstructions based on clumped isotope measurements in bivalve shells which, critically, do not rely on these assumptions. Our new approach reconstructs highly precise higher mid-latitude (~50°N) monthly temperatures from individual oyster and rudist shells of the Campanian (78 million years ago) greenhouse period (15—27 °C seasonal range). Our analysis demonstrates that seasonal bias and previous assumptions about sea water oxygen isotope composition can lead to highly inaccurate temperature reconstructions, distorting our understanding of the behavior of greenhouse climates and our ability to model them. Our results agree with fully coupled climate model simulations showing greenhouse climates outside the tropics were warmer and more seasonal than previously thought.

scholarly journals First absolute seasonal temperature estimates for greenhouse climate from clumped isotopes in bivalve shells

2020 ◽  
Author(s):  
Niels de Winter ◽  
Inigo Müller ◽  
Ilja Kocken ◽  
Nicolas Thibault ◽  
Clemens Vinzenz Ullmann ◽  
...  
Keyword(s):  
Seasonal Variability ◽  
Climate Model ◽  
Sea Water ◽  
Isotope Composition ◽  
Seasonal Temperature ◽  
Deep Time ◽  
Temperature Reconstructions ◽  
Climate Model Simulations ◽  
Clumped Isotope ◽  
Bivalve Shells

Abstract The seasonal variability of sea surface temperatures plays a fundamental role in climate dynamics and species distribution. As such, it is essential to better understand seasonal variability in warm climates of the past. Previous reconstructions of seasonality in deep time are relatively unconstrained, relying on unsupported assumptions such as estimates of seawater composition and negligible seasonal bias. This work presents the first absolute seasonal temperature reconstructions based on clumped isotope measurements in bivalve shells which, critically, do not rely on these assumptions. Our new approach reconstructs highly precise mid-latitude (~50°N) monthly temperatures from individual oyster and rudist shells of the Campanian (78 million years ago) greenhouse period (15—27 °C seasonal range). Our analysis demonstrates that seasonal bias and previous assumptions about sea water oxygen isotope composition can lead to highly inaccurate temperature reconstructions, distorting our understanding of the behavior of greenhouse climates and our ability to model them. Our results agree remarkably well with fully coupled climate model simulations showing greenhouse climates outside the tropics were warmer with higher seasonality than previously thought.

scholarly journals Absolute seasonal temperature estimates from clumped isotopes in bivalve shells suggest warm and variable greenhouse climate

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Niels J. de Winter ◽  
Inigo A. Müller ◽  
Ilja J. Kocken ◽  
Nicolas Thibault ◽  
Clemens V. Ullmann ◽  
...  
Keyword(s):  
Seasonal Variability ◽  
Sea Water ◽  
Isotope Composition ◽  
Sea Surface ◽  
Mean Annual Temperature ◽  
Seasonal Temperature ◽  
Sea Surface Temperatures ◽  
Surface Temperatures ◽  
Temperature Reconstructions ◽  
Bivalve Shells

AbstractSeasonal variability in sea surface temperatures plays a fundamental role in climate dynamics and species distribution. Seasonal bias can also severely compromise the accuracy of mean annual temperature reconstructions. It is therefore essential to better understand seasonal variability in climates of the past. Many reconstructions of climate in deep time neglect this issue and rely on controversial assumptions, such as estimates of sea water oxygen isotope composition. Here we present absolute seasonal temperature reconstructions based on clumped isotope measurements in bivalve shells which, critically, do not rely on these assumptions. We reconstruct highly precise monthly sea surface temperatures at around 50 °N latitude from individual oyster and rudist shells of the Campanian greenhouse period about 78 million years ago, when the seasonal range at 50 °N comprised 15 to 27 °C. In agreement with fully coupled climate model simulations, we find that greenhouse climates outside the tropics were warmer and more seasonal than previously thought. We conclude that seasonal bias and assumptions about seawater composition can distort temperature reconstructions and our understanding of past greenhouse climates.

Absolute temperature seasonality from skeletal carbonates—Techniques and limitations of oxygen- and clumped isotope analyses

2020 ◽  
Author(s):  
Niels de Winter ◽  
Rob Witbaard ◽  
Clemens Ullmann ◽  
Anne Soerensen ◽  
Nicolas Thibault ◽  
...  
Keyword(s):  
High Resolution ◽  
Climate Models ◽  
Sea Water ◽  
Isotope Composition ◽  
Simulated Data ◽  
Absolute Temperature ◽  
Deep Time ◽  
Climate Reconstructions ◽  
Wide Range ◽  
Clumped Isotope

<p>The carbonate skeletons of marine organisms are unique archives for high-resolution climate reconstructions. Well-preserved specimens potentially allow for seasonal to even daily scale variability reconstructions of climate and environment  in deep time (pre-Quaternary), providing otherwise unavailable snapshots of climate variability during greenhouse periods (e.g. Steuber et al., 2005; Ivany et al., 2008; de Winter et al., 2017). However, uncertainties on past seawater compositions hamper use of the popular stable oxygen isotope ratio (δ<sup>18</sup>O) as proxy for paleotemperature reconstructions. The use of the independent carbonate clumped isotope (Δ<sub>47</sub>) paleothermometer, which is insensitive to changes in seawater composition, on these promising fossil archives is complicated because of sample size limitations (Fernandez et al., 2017; Bernasconi et al., 2018).</p><p>In an attempt to circumvent these issues and use the δ<sup>18</sup>O and Δ<sub>47</sub> measurements jointly for accurate seasonal reconstructions of temperature and seawater isotope composition, we present a novel data reduction approach that combines Δ<sub>47</sub> measurements of small (~100 µg) serially sampled aliquots to estimate summer and winter temperatures in mollusk shell records. When applied on Δ<sub>47</sub> and δ<sup>18</sup>O measurements in the same specimens, combined with accurate shell chronologies, this approach reconstructs seasonal differences in temperature and seawater composition in a coastal site from the Campanian (Late Cretaceous) high-latitudes.</p><p>To test the robustness of these reconstructions, we apply different approaches of combining δ<sup>18</sup>O and Δ<sub>47</sub> data on a wide range of simulated data representing various scenarios of variability in growth rate, temperature and sea water composition typical for the natural shallow marine environments of carbonate-producers. This approach tests how choices such as sampling resolution and the method of data collection and reduction influence the accuracy and reproducibility of (paleo)seasonality reconstructions in these scenarios.</p><p>Finally, we present preliminary data of δ<sup>18</sup>O and Δ<sub>47</sub> analyses on bivalve specimens grown under controlled temperature conditions that allow us to calibrate the techniques above for temperature reconstructions. Together, these investigations pave the way for accurate, high-resolution climate reconstructions in deep time. These reconstructions provide valuable information on the dynamics of greenhouse climates, against which climate models can be compared to improve predictions of future climate.</p><p><strong>References</strong></p><p>Bernasconi, S. M., et al. Geochemistry, Geophysics, Geosystems, 19(9), 2895–2914, 2018.</p><p>Fernandez, A. et al. Geochemistry, Geophysics, Geosystems, 18(12), 4375–4386, 2017.</p><p>Ivany et al. Geological Society of America Bulletin, 120(5–6), 659–678, 2008.</p><p>Steuber, T. et al. Nature, 437(7063), 1341–1344, 2005.</p><p>de Winter, N. J. et al. Palaeogeography, Palaeoclimatology, Palaeoecology, 485, 740–760, 2017.</p>

Advances in high-resolution paleoclimate reconstructions using growth experiments, age modelling and clumped isotope analyses

2021 ◽  
Author(s):  
Niels de Winter ◽  
Rob Witbaard ◽  
Inigo Müller ◽  
Ilja Kocken ◽  
Tobias Agterhuis ◽  
...  
Keyword(s):  
High Resolution ◽  
Trace Element ◽  
Shell Growth ◽  
Seasonal Temperature ◽  
Human Scale ◽  
Temperature Reconstructions ◽  
Shell Chemistry ◽  
Clumped Isotope ◽  
Isotope Analyses ◽  
Bivalve Shells

<p>Geochemical records from incremental carbonate archives, such as fossil mollusk shells, contain information on climate and environmental change at the resolution of days to decades (e.g. Schöne and Gillikin, 2013; Ivany, 2012). These high-resolution paleoclimate data, providing snapshots of past climate change on a human scale, complement more conventional reconstructions on a geological timescale of thousands to millions of years. Recent innovations in geochemical techniques such as high-resolution trace element and clumped isotope analyses provide the unique potential to improve the accuracy and resolution of these high-resolution climate reconstructions in the near future (see e.g. de Winter et al., 2020a; b; Caldarescu et al., 2021). However, to be able to make the most out of these new techniques requires a more detailed understanding of the timing and mechanisms of mollusk shell growth as well as the relationship between environment and shell chemistry on daily to weekly timescales.</p><p>The UNBIAS (UNravelling BIvAlve Shell chemistry) project combines investigations on lab-grown modern bivalve shells with reconstructions based on fossil shell material from past greenhouse periods in an attempt to improve our understanding of short-term temperature variability in warm climates. Samples from cultured shells labeled with a novel trace element spiking method are used to calibrate accurate temperature reconstructions from bivalve shells using the state-of-the-art clumped isotope method. As a result, we present a temperature calibration of clumped isotope measurements on aragonitic shell carbonates. New statistical routines are developed to accurately date microsamples within shells relative to the seasonal cycle (ShellChron; de Winter, 2020) and to strategically combine these microsamples for seasonal reconstructions of temperature and salinity from fossil shells (seasonalclumped, de Winter et al., 2020c; de Winter, 2021). We present the first results of this integrated seasonal reconstruction approach on fossil bivalve shells from the Pliocene Warm Period and Late Cretaceous greenhouse of northwestern Europe as well as an outlook on future plans within the UNBIAS project.</p><p> </p><p><strong>References</strong></p><p>Caldarescu, D. E. et al. Geochimica et Cosmochimica Acta 294, 174–191 (2021).</p><p>de Winter, N. J. ShellChron v0.2.8: Builds Chronologies from Oxygen Isotope Profiles in Shells. (2020).</p><p>de Winter, N. J. seasonalclumped v0.3.2: Toolbox for Seasonal Temperature Reconstructions using Clumped Isotope Analyses. (2021).</p><p>de Winter, N. J. et al. Paleoceanography and Paleoclimatology 35, e2019PA003723 (2020a).</p><p>de Winter, N. J. et al. Nature Communications in Earth and Environment (in review; 2020b) doi:10.21203/rs.3.rs-39203/v2.</p><p>de Winter, N., Agterhuis, T. & Ziegler, M. Climate of the Past Discussions 1–52 (2020c) doi:https://doi.org/10.5194/cp-2020-118.</p><p>Ivany, L. C. The Paleontological Society Papers 18, 133–166 (2012).</p><p>Schöne, B. R. & Gillikin, D. P. Palaeogeography, Palaeoclimatology, Palaeoecology 373, 1–5 (2013).</p>

scholarly journals Marine temperatures underestimated for past greenhouse climate

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Madeleine L. Vickers ◽  
Stefano M. Bernasconi ◽  
Clemens V. Ullmann ◽  
Stefanie Lode ◽  
Nathan Looser ◽  
...  
Keyword(s):  
Surface Waters ◽  
Isotope Composition ◽  
Stable Oxygen Isotopes ◽  
Greenhouse Climate ◽  
Temperature Reconstructions ◽  
Stable Oxygen ◽  
Clumped Isotope ◽  
Earth’S Climate ◽  
Extinct Group

AbstractUnderstanding the Earth’s climate system during past periods of high atmospheric CO2 is crucial for forecasting climate change under anthropogenically-elevated CO2. The Mesozoic Era is believed to have coincided with a long-term Greenhouse climate, and many of our temperature reconstructions come from stable isotopes of marine biotic calcite, in particular from belemnites, an extinct group of molluscs with carbonate hard-parts. Yet, temperatures reconstructed from the oxygen isotope composition of belemnites are consistently colder than those derived from other temperature proxies, leading to large uncertainties around Mesozoic sea temperatures. Here we apply clumped isotope palaeothermometry to two distinct carbonate phases from exceptionally well-preserved belemnites in order to constrain their living habitat, and improve temperature reconstructions based on stable oxygen isotopes. We show that belemnites precipitated both aragonite and calcite in warm, open ocean surface waters, and demonstrate how previous low estimates of belemnite calcification temperatures has led to widespread underestimation of Mesozoic sea temperatures by ca. 12 °C, raising estimates of some of the lowest temperature estimates for the Jurassic period to values which approach modern mid-latitude sea surface temperatures. Our findings enable accurate recalculation of global Mesozoic belemnite temperatures, and will thus improve our understanding of Greenhouse climate dynamics.

Clumped Isotope Paleothermometry: Principles, Applications, and Challenges

2012 ◽  
Vol 18 ◽  
pp. 101-114 ◽  
Author(s):  
Hagit P. Affek
Keyword(s):  
Isotope Composition ◽  
Isotope Analysis ◽  
Atomic Scale ◽  
Clumped Isotopes ◽  
Temperature Dependent ◽  
Deep Time ◽  
Diagenetic Alteration ◽  
Carbonate Formation ◽  
Rare Isotopes ◽  
Clumped Isotope

Clumped isotopes geochemistry measures the thermodynamic preference of two heavy, rare, isotopes to bind with each other. This preference is temperature dependent, and is more pronounced at low temperatures. Carbonate clumped isotope values are independent of the carbonate δ13C and δ18O, making them independent of the carbon or oxygen composition of the solution from which the carbonate precipitated. At equilibrium, it is therefore a direct proxy for the temperature in which the carbonate mineral formed. In most cases, carbonate clumped isotopes record the temperature of carbonate formation, irrespective of the mineral form (calcite, aragonite, or bioapatite) or the organism making it. The carbonate formation temperatures obtained from carbonate clumped isotope analysis can be used in conjunction with the δ18O of the same carbonate, to constrain the oxygen isotope composition of the water from which the carbonate has precipitated. There are, however, cases of deviation from thermodynamic equilibrium, where both clumped and oxygen isotopes are offset from the expected values. Such carbonates must be characterized and calibrated separately. For deep-time applications, special care must be paid to the preservation of the original signal, in particular with respect to diagenetic alteration associated with atomic scale diffusion that may be undetectable by common tests for diagenesis.

scholarly journals The DeepMIP contribution to PMIP4: methodologies for selection, compilation and analysis of latest Paleocene and early Eocene climate proxy data, incorporating version 0.1 of the DeepMIP database

2019 ◽  
Vol 12 (7) ◽  
pp. 3149-3206 ◽  
Author(s):  
Christopher J. Hollis ◽  
Tom Dunkley Jones ◽  
Eleni Anagnostou ◽  
Peter K. Bijl ◽  
Margot J. Cramwinckel ◽  
...  
Keyword(s):  
Climate Models ◽  
Climate Model ◽  
Early Eocene ◽  
Proxy Data ◽  
Time Model ◽  
Deep Time ◽  
Climate Proxy ◽  
Early Eocene Climatic Optimum ◽  
Climate Model Simulations ◽  
Atmospheric Co2 Concentrations

Abstract. The early Eocene (56 to 48 million years ago) is inferred to have been the most recent time that Earth's atmospheric CO2 concentrations exceeded 1000 ppm. Global mean temperatures were also substantially warmer than those of the present day. As such, the study of early Eocene climate provides insight into how a super-warm Earth system behaves and offers an opportunity to evaluate climate models under conditions of high greenhouse gas forcing. The Deep Time Model Intercomparison Project (DeepMIP) is a systematic model–model and model–data intercomparison of three early Paleogene time slices: latest Paleocene, Paleocene–Eocene thermal maximum (PETM) and early Eocene climatic optimum (EECO). A previous article outlined the model experimental design for climate model simulations. In this article, we outline the methodologies to be used for the compilation and analysis of climate proxy data, primarily proxies for temperature and CO2. This paper establishes the protocols for a concerted and coordinated effort to compile the climate proxy records across a wide geographic range. The resulting climate “atlas” will be used to constrain and evaluate climate models for the three selected time intervals and provide insights into the mechanisms that control these warm climate states. We provide version 0.1 of this database, in anticipation that this will be expanded in subsequent publications.

scholarly journals Estimating 750 years of temperature variations and uncertainties in the Pyrenees by tree-ring reconstructions and climate simulations

2012 ◽  
Vol 8 (3) ◽  
pp. 919-933 ◽  
Author(s):  
I. Dorado Liñán ◽  
U. Büntgen ◽  
F. González-Rouco ◽  
E. Zorita ◽  
J. P. Montávez ◽  
...  
Keyword(s):  
Tree Ring ◽  
Climate Model ◽  
Maximum Density ◽  
Positive Trend ◽  
Temperature Variations ◽  
Model Simulations ◽  
Mean Temperature ◽  
Climate Simulations ◽  
Temperature Reconstructions ◽  
Climate Model Simulations

Abstract. Past temperature variations are usually inferred from proxy data or estimated using general circulation models. Comparisons between climate estimations derived from proxy records and from model simulations help to better understand mechanisms driving climate variations, and also offer the possibility to identify deficiencies in both approaches. This paper presents regional temperature reconstructions based on tree-ring maximum density series in the Pyrenees, and compares them with the output of global simulations for this region and with regional climate model simulations conducted for the target region. An ensemble of 24 reconstructions of May-to-September regional mean temperature was derived from 22 maximum density tree-ring site chronologies distributed over the larger Pyrenees area. Four different tree-ring series standardization procedures were applied, combining two detrending methods: 300-yr spline and the regional curve standardization (RCS). Additionally, different methodological variants for the regional chronology were generated by using three different aggregation methods. Calibration verification trials were performed in split periods and using two methods: regression and a simple variance matching. The resulting set of temperature reconstructions was compared with climate simulations performed with global (ECHO-G) and regional (MM5) climate models. The 24 variants of May-to-September temperature reconstructions reveal a generally coherent pattern of inter-annual to multi-centennial temperature variations in the Pyrenees region for the last 750 yr. However, some reconstructions display a marked positive trend for the entire length of the reconstruction, pointing out that the application of the RCS method to a suboptimal set of samples may lead to unreliable results. Climate model simulations agree with the tree-ring based reconstructions at multi-decadal time scales, suggesting solar variability and volcanism as the main factors controlling preindustrial mean temperature variations in the Pyrenees. Nevertheless, the comparison also highlights differences with the reconstructions, mainly in the amplitude of past temperature variations and in the 20th century trends. Neither proxy-based reconstructions nor model simulations are able to perfectly track the temperature variations of the instrumental record, suggesting that both approximations still need further improvements.

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