Journal cover Journal topic
Biogeosciences An interactive open-access journal of the European Geosciences Union
Biogeosciences, 13, 1223-1235, 2016
https://doi.org/10.5194/bg-13-1223-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
29 Feb 2016
Age structure, carbonate production and shell loss rate in an Early Miocene reef of the giant oyster Crassostrea gryphoides
Mathias Harzhauser1, Ana Djuricic2, Oleg Mandic1, Thomas A. Neubauer1, Martin Zuschin3, and Norbert Pfeifer2 1Natural History Museum Vienna, Geological-Paleontological Department, Vienna, Austria
2TU Wien, Department of Geodesy and Geoinformation, Vienna, Austria
3University of Vienna, Department of Paleontology, Vienna, Austria
Abstract. We present the first analysis of population structure and cohort distribution in a fossil oyster shell bed based on 1121 shells of the giant oyster Crassostrea gryphoides (von Schlotheim, 1813). Data derive from terrestrial laser scanning of a Lower Miocene shell bed covering 459 m2. Within two transects, individual shells were manually outlined on a digital surface model and cross-checked based on high-resolution orthophotos, resulting in accurate information on center line length and area of exposed shell surface. A growth model was calculated, revealing this species as the fastest growing and largest Crassostrea known so far. Non-normal distribution of size, area and age data hints at the presence of at least four distinct recruitment cohorts. The rapid decline of frequency amplitudes with age is interpreted to be a function of mortality and shell loss. The calculated shell half-lives range around a few years, indicating that oyster reefs were geologically short-lived structures, which could have been fully degraded on a decadal scale.

Crassostrea gryphoides reefs were widespread and common along the Miocene circum-Tethyan coasts. Given its enormous growth performance of  ∼  150 g carbonate per year this species has been an important carbonate producer in estuarine settings. Yet, the rapid shell loss impeded the formation of stable structures comparable to coral reefs.


Citation: Harzhauser, M., Djuricic, A., Mandic, O., Neubauer, T. A., Zuschin, M., and Pfeifer, N.: Age structure, carbonate production and shell loss rate in an Early Miocene reef of the giant oyster Crassostrea gryphoides, Biogeosciences, 13, 1223-1235, https://doi.org/10.5194/bg-13-1223-2016, 2016.
Publications Copernicus
Download
Short summary
We present the first analysis of population structure and cohort distribution in a fossil oyster reef. Data are derived from Terrestrial Laser Scanning of a Miocene shell bed covering 459 m². A growth model was calculated, revealing this species as the giant oyster Crassostrea gryphoides was the fastest growing oyster known so far. The shell half-lives range around few years, indicating that oyster reefs were geologically short-lived structures, which were degraded on a decadal scale.
We present the first analysis of population structure and cohort distribution in a fossil oyster...
Share