HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Full Text (PDF) 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 ISI Web of Science (31) Citing Articles via Google Scholar Google Scholar Articles by DUPRAZ, C. Articles by STRASSER, A. Search for Related Content GeoRef GeoRef Citation

Nutritional Modes in Coral—Microbialite Reefs (Jurassic, Oxfordian, Switzerland): Evolution of Trophic Structure as a Response to Environmental Change

¹ Rosenstiel School of Marine and Atmospheric Sciences, University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149^,*
2 Institute of Geology and Paleontology, University of Fribourg, Pérolles, 1700 Fribourg, Switzerland

Detailed study of Oxfordian coral-microbialite reefs in the Swiss Jura Mountains has identified major paleoecological variations in space and time, which are attributed to environmental changes. Micro- and macroscale semi-quantitative analyses of microbialite types, micro-encrusters, bioerosion, corals, and other macrofauna composing the reefal facies were performed. Three main trophic structures (dominant nutritional modes) were recognized: phototrophic-dominated, balanced photo-heterotrophic, and heterotrophic-dominated. A phototrophic (light-dependant) fauna dominated reefs growing in pure carbonate and nutrient- poor environments, where sedimentation rate was the main factor controlling reef growth. In mixed siliciclastic-carbonate platform environments, a balanced photo-heterotrophic fauna with periodical shifts to heterotrophic-dominated associations was induced by freshwater and sediment run-off into closed, shallow lagoons. In this case, the main factors controlling reef growth were the distribution and accumulation of terrigenous sediment on the platform and/or associated nutrient availability. The balanced photo-heterotrophic structure found in mixed carbonate-siliciclastic settings produced the most diversified reefs, suggesting that these Oxfordian reefs preferentially thrived in water moderately charged with nutrients (mesotrophic environment). In the case of strong siliciclastic accumulation and/or strong increase in nutrient availability, coral reef diversity dropped drastically and heterotrophs dominated the trophic structure. A model of the evolution of trophic structure in these reefs as a function of the governing environmental factors is proposed. Focusing on the dominant nutritional mode at each step in reef evolution allows a detailed characterization of reefal structure and a better understanding of the processes leading to coral reef settlement, development, and demise.

This article has been cited by other articles:

				M. E.J. Wilson Development of Equatorial Delta-Front Patch Reefs During the Neogene, Borneo Journal of Sedimentary Research, January 1, 2005; 75(1): 114 - 133. [Abstract] [Full Text] [PDF]

				A Late Jurassic Carbonate Ramp Colonized by Sponges and Benthic Microbial Communities (External Prebetic, Southern Spain) Palaios, December 1, 2003; 18(6): 528 - 545.