Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Figures Only Full Text Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (5) Citing Articles via Google Scholar Google Scholar Articles by Beaufort, L. Search for Related Content GeoRef GeoRef Citation

Weight estimates of coccoliths using the optical properties (birefringence) of calcite

CNRS-Université Aix-Marseille III, CEREGE, Europôle de l’Arbois, BP 80, 13545 Aix-en-Provence Cedex 04, France email: beaufort{at}cerege.fr

The coccolithophores are among the few organisms of the phytoplankton to calcify. Although together with the planktonic foraminifera they dominate calcite production in the open ocean, the amount of calcite they secrete is difficult to determine. The amount of calcite in the form of coccoliths that is dissolved during sedimentation is also difficult to estimate as is the amount of calcite represented by sedimented coccoliths. Because of their minuteness, coccoliths cannot be directly weighed. Instead, indirect methods must be used to estimate their weight.

I describe here a method that allows quick estimations of the weight of individual coccoliths, based on the measure of their brightness when viewed in cross-polarized light. This birefringence method can only be applied to the group Heliolithae (excluding some of the coccoliths produced in the Family Coccolithaceae). For Coccolithaceae and some Ortholithae an estimate of the weight can be made using a correcting factor. The birefringence method is highly reproducible (+/– 0.13pg). However, a significant systematic error of 13.5% may occur when coccoliths with asymmetrical appearance in cross polarized light (e.g., Helicospheara carteri) are not measured in specific orientations.

This article has been cited by other articles:

				M.-P. Aubry A major Pliocene coccolithophore turnover: Change in morphological strategy in the photic zone Geological Society of America Special Papers, January 1, 2007; 424(0): 25 - 51. [Abstract] [Full Text] [PDF]