Journal ArticleDOI
Warm tropical sea surface temperatures in the Late Cretaceous and Eocene epochs
Paul Nicholas Pearson,Peter V. Ditchfield,Joyce M. Singano,Katherine G. Harcourt-Brown,Christopher J. Nicholas,Richard K. Olsson,Nicholas J Shackleton,Michael A Hall +7 more
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TLDR
New data from exceptionally well preserved foraminifer shells extracted from impermeable clay-rich sediments indicate that for the intervals studied, tropical sea surface temperatures were at least 28–32 °C, more in line with the understanding of the geographical distributions of temperature-sensitive fossil organisms and the results of climate models with increased CO2 levels.Abstract:
Climate models with increased levels of carbon dioxide predict that global warming causes heating in the tropics, but investigations of ancient climates based on palaeodata have generally indicated cool tropical temperatures during supposed greenhouse episodes. For example, in the Late Cretaceous and Eocene epochs there is abundant geological evidence for warm, mostly ice-free poles, but tropical sea surface temperatures are generally estimated to be only 15-23 degrees C, based on oxygen isotope palaeothermometry of surface-dwelling planktonic foraminifer shells. Here we question the validity of most such data on the grounds of poor preservation and diagenetic alteration. We present new data from exceptionally well preserved foraminifer shells extracted from impermeable clay-rich sediments, which indicate that for the intervals studied, tropical sea surface temperatures were at least 28-32 degrees C. These warm temperatures are more in line with our understanding of the geographical distributions of temperature-sensitive fossil organisms and the results of climate models with increased CO2 levels.read more
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Marked Decline in Atmospheric Carbon Dioxide Concentrations During the Paleogene
Mark Pagani,James C Zachos,James C Zachos,James C Zachos,Katherine H. Freeman,Katherine H. Freeman,Katherine H. Freeman,Brett J. Tipple,Brett J. Tipple,Brett J. Tipple,S. M. Bohaty,S. M. Bohaty,S. M. Bohaty +12 more
TL;DR: Stable carbon isotopic values of di-unsaturated alkenones extracted from deep sea cores are used to reconstruct pCO2 from the middle Eocene to the late Oligocene and demonstrate that it ranged between 1000 to 1500 parts per million by volume in the middle to late Eocene, then decreased in several steps during theOligocene, and reached modern levels by the latest Oligaen.
Journal ArticleDOI
The Geological Record of Ocean Acidification
Bärbel Hönisch,Andy Ridgwell,Daniela N. Schmidt,Ellen Thomas,Ellen Thomas,Samantha J. Gibbs,Appy Sluijs,Richard E. Zeebe,Lee R. Kump,Rowan C. Martindale,Sarah E. Greene,Sarah E. Greene,Wolfgang Kiessling,Justin B. Ries,James C Zachos,Dana L. Royer,Stephen Barker,Thomas M Marchitto,Ryan P. Moyer,Carles Pelejero,Patrizia Ziveri,Patrizia Ziveri,Gavin L. Foster,Branwen Williams +23 more
TL;DR: This paper reviewed events exhibiting evidence for elevated atmospheric CO2, global warming, and ocean acidification over the past ~300 million years of Earth's history, some with contemporaneous extinction or evolutionary turnover among marine calcifiers.
Journal ArticleDOI
Oceanic anoxic events and plankton evolution: Biotic response to tectonic forcing during the mid-Cretaceous
TL;DR: In this paper, the authors investigated the link between submarine volcanism, plankton evolution, and the cycling of carbon through the marine biosphere, and concluded that there were important linkages between submarine volcano activity and marine productivity.
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Impacts of ocean acidification on coral reefs and other marine calcifiers : a guide for future research
Joan A. Kleypas,Denis Allemand +1 more
TL;DR: In this paper, the authors present the results of a workshop on how the marine calcium carbonate system, and marine calcifiers, will respond to increasing concentrations of carbon dioxide in the ocean.
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CO2-forced climate thresholds during the Phanerozoic
TL;DR: In this paper, the authors compare 490 published proxy records of CO2 spanning the Ordovician to Neogene with records of global cool events to evaluate the strength of CO 2-temperature coupling over the Phanerozoic (last 542my).
References
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Trends, Rhythms, and Aberrations in Global Climate 65 Ma to Present
TL;DR: This work focuses primarily on the periodic and anomalous components of variability over the early portion of this era, as constrained by the latest generation of deep-sea isotope records.
Journal ArticleDOI
Atmospheric carbon dioxide concentrations over the past 60 million years
TL;DR: The boron-isotope ratios of ancient planktonic foraminifer shells are used to estimate the pH of surface-layer sea water throughout the past 60 million years, which can be used to reconstruct atmospheric CO2 concentrations.
Book
Modern Planktonic Foraminifera
TL;DR: This chapter discusses the taxonomy and Species Features of Spinose Planktonic Foraminifera, and the development of Symbiosis, Commensalism and Parasitism, as well as the relationships between Symbiont Morphology and Host Physiological Interactions.
Journal ArticleDOI
Effect of seawater carbonate concentration on foraminiferal carbon and oxygen isotopes
TL;DR: In this paper, the authors reported experimental measurements on living symbiotic and non-symbiotic plankton foraminifera (Orbulina universa and Globigerina bulloides respectively) showing that the 13C/12C and 18O/16O ratios of the calcite shells decrease with increasing seawater [CO32−].