Quigg, Antonietta1, Bas van de Schootburge1, Mimi Katz2, Susanne
Feist-Burkhardt3, Yair Rosenthal1, Paul Falkowski1
(1) Rutgers University, New Brunswick, NJ
(2) Rutgers University, Piscataway, NJ
(3) Natural History Museum, London, United Kingdom
ABSTRACT: The Impact of an Ocean Anoxic Event on the Phytoplankton Flora of the Early Jurassic
The work was undertaken as part of the EREUPT (Evolution and Radiation of Eukaryotic Phytoplankton Taxa) Biocomplexity program. The focus of this multidisciplinary research project is to understand the historical origins and environmental conditions that led to selection and radiation of the major eukaryotic phytoplankton taxa, and the ecological processes that contribute to their continued success in the contemporary ocean. The research presented here utilizes a combination of geological, ecological, and chemical approaches to understand the factors influencing eukaryotic phytoplankton flora assemblages in the paleao-ocean. We examined the elemental composition (C, N, P, major cations and trace elements) of bulk rock samples (predominately black shales) from the Weiach Borehole (N Switzerland) spanning the complete Early Jurassic. These findings were compared to an earlier study (Quigg et al. 2003 Nature 425: 291-294) on the elemental composition of 15 species of contemporary marine phytoplankton from 5 taxa. It appears that the elemental composition of the black shales directly reflects the dominate phytoplankton producers and the redox state of the water column during the Early Jurassic. A shift in community flora (as seen in changes in both the fossil record and the black shale composition) is coincident with an ocean anoxic event, and consistent with phytoplankton responses to perturbations in the bioavailability of nutrients and trace elements essential to growth and photosynthesis. This evolutionary “reference” will be included in modeling efforts of community structure in contemporary oceans.
AAPG Search and Discovery Article #90026©2004 AAPG Annual Meeting, Dallas, Texas, April 18-21, 2004.