This project associates marine biologists, paleaoclimatologists, analysts of structural and compositional properties of biominerals, experimental and theoretical physicists. This diversity reflects the two major questions underlying the BioCalc project.
1. In recent climate change studies, high resolution measurements made on biological Cacarbonate resulted in a growing number of “erratic results”. This led some palaeoclimatologists to require “a new strategy”* to replace the present empiricism in the use of biominerals as environmental archives.
2. Progress in this domain obviously depends on a deeper understanding of the biocrystallization patterns and mechanisms, a fact that reminds us of the intriguing and still unresolved question of the “vital effect”**, i.e. the species-specific responses of biocrystallization process to environmental influences.
Through a biomineralization-based approach, the BioCalc team aims at bringing new insights into these two connected problems. Assumption is made that through a standard analytical sequence applied to a wide series of biogenic carbonates, progression from the diversity of morphological features towards fine scale structures and molecular forces will result in recognition of basically common mechanisms and progress in their understanding.
The project is organized in four sections. In a series of biological stations and natural sites with a worldwide distribution, calcifying organisms will be cultivated in continuously recorded conditions. Time-marking fluorochrome traces will be imprinted within the growing skeletons (section 1). Microdiffraction and microstructural analyses will be carried out to reveal the crystal lattice peculiarities and the fine-scale growth mode of calcareous units. In addition, the species-specific sets of mineralizing macromolecules will be isolated and biochemically characterized (section 2). Chemical and isotopic measurements will be made between the fluorescent time-marks of calcareous skeletons, the growth-patterns revealed by microstructural analysis allowing a precise correlation with environment records to be obtained (section 3). Based on this series of coordinated experiments and fine scale measurements, relevant models of the environment recording will be developed, providing climate change investigators with an immediate feed-back (4a). In parallel, isolated organic matrices (Cf. section 2) will provide experimentalists and theoretical physicists with a number of case-studies to examine and modelize interactions between the mineral subtrates of skeleton units and the corresponding organic macromolecules. This will result in a consistent basis for calculating the forces which may account for the high ordering observed in biocrystallization process (4b).
* Lough, 2003, Paleoceanography, Paleoclimatology, Paleontology, 204: 115-143.
** Urey et al., 1951, Bull. Geol. Soc. Am., 62: 399-416
Professor Jean-Pierre Cuif (Project Leader)
CNRS, Laboratoire IDES - UMR 8148, Dépt Géologie, Fac. Sciences, Université de Paris XI / Orsay, Orsay, France
Professor Jelle Bijma
Alfred-Wegener Institut für Polar- und Meeresforschung, Bremerhaven, Germany
Dr. Yannicke Dauphin
Université Paris-Sud 11, Orsay, France
Dr. Jean Doucet
Université Paris-Sud 11, Orsay, France
Dr. Anne Juillet-Leclerc
Laboratoire des Sciences du Climat et de l’Environnement, Gif-sur-Yvette, France
Dr. Anders Christian Dalgaard Meibom
Muséum National d’Histoire Naturelle, Paris, France
Dr. Lionel Mercury
Université Paris-Sud 11, Orsay, France
Dr. Margaret Cusack
University of Glasgow, Glasgow, United Kingdom
Dr. Luc Ortlieb
Laboratoire Paléotropique-IRD, Bondy, France
