Studies

The project will conduct ten major studies each of which will contribute to one or more of the project's aims:

1. Biostratigraphic control [AIM 1]J. Tong & others

   Based on the previously published data, recent results derived from current IGCP 467 (led by M. Orchard, ceasing in 2008) and our further stratigraphic works, we will attempt to establish global Early-Middle Triassic biostratigraphic frameworks, which provide a useful and sound base for studying community ecology.

2. Recovery pattern of fossil goups and Preservational and sampling biases [AIM 2]S. Crasquin, Z.Q. Chen, R.J. Twitchett

   This study provides an update on recovery patterns of various fossil groups. Effects of the incompleteness of fossil records on biodiversity changes over the mass extinction event are emphasized in this project [34]. Phylogenetic analysis is also employed to determine the true recovery timing of the selected fossil clades (brachiopods, ostracods, ophiuroids and foraminifers).

3. Recovery model of palaeo-communities [AIMS 3, 4, 7]R.J. Twitchett, Y. Aita

   To quantify the benthic recovery process, we will apply a palaeoecologic recovery model (Fig. 1) to this project. The recovery rates and stages of every benthic community will be determined by utilising four discrimination criteria stated above. Ecologic information indicated by trace fossils are also ultilized to commity ecologic analysis. The new recovery model is formulated for plankontic community.

4. Community ecologic analysis [AIMS 3, 4, 5]M.L. Fraiser, R. J. Twitchett, Z.Q. Chen & others

   We will undertake community ecologic analysis for palaeocommunities recognized from various environmental settings from nearshore to deep basin and different climate zones. The ultimate goal is establish an electronic global database of ecosystem types during the P-Tr transition. The roles of both disaster and Lazarus taxa as well as biotic predatory/or parasitic interactions in recovery communities are also tested.

5. Early Triassic microbial community [AIMS 3, 5, 7]S. Kershaw, S. Crasquin

   Microbialites (stromatolites, thrombolites and dendrolites) have been regarded as the disaster taxa of biotic mass extinctions ([28], [31]), and they are extremely abundant in the Early Triassic ([28], [15], [19], [24], [1]). Other microbialites may be preserved in the forms of oolites and wrinkle structures [26-27]. We will test this hypothesis that microbialites may have provided the basic food chains for restructuring of the defaunated ecosystems in the Early Triassic. The relationships between microbialites and metazoans within the microbialite-dominated community and between microbialite and metazoan communities will be determined.

6. Collapse and re-building of P/Tr reefs [AIMS 4, 7]J. Tong, Z.Q. Chen, S. Kershaw

   To understand the evolution of long-lived reef systems and provide strategies for the successful management of modern systems such as the Great Barrier Reef, we choose P-Tr reef facies sections in South China to study the impact and recovery of metazoan reefs over the P/Tr transition.

7. Palaeophysiology of P/Tr mass extinction and its aftermath [AIMS 3, 4, 7]Co-ordinators are being recruited

   More info needs to be added here.

8. Biomarker studie s [AIMS 6,7]K. Grice, R.J. Twitchett, T. Algeo, S. Kershaw and others

   The analysis of biomarkers and their individual stable carbon isotopes has shown that green sulfur bacteria (Chlorobiaceae) were abundant organisms prevailing in the upper part of the water-colum of the ancient seas at many locations, including Australia, South China, E. Greenland and Kashmir-Tibet, during the Late Permian and Early Triassic period [1], pointing to widespread euxinia associated with this large mass extinction event. These methods will also be applied to this project and an eletronic global database of geochemical and biomarker analysis data of the P-Tr interval will be constructed during the life course of the project including an investigation of compounds associated with microbialites. In addition a set of novel biomarkers derived from algal toxins only identified in P-Tr samples will be investigated.

9. Isotopic geochemistry  [AIMS 6,7]T. Algeo, K. Grice & others

   Recent studies show that the positive-negative shifting cycles of carbon isotope excursions may indicate that large perturbations of the carbon cycle, reflecting environmental changes [21]. The stable carbon isotopic ratio may also indicate CO2 levels in the atmosphere-ocean system, reflecting climate changes [16]. An electronic global database of geochemical and biomarker analysis data of the P-Tr interval will be constructed during the life course of the project.

10. Restoration traits of marine ecosystems and comparison with modern defaunation event [AIM 8]Z.Q. Chen, R.J. Twitchett, K. GriceBy comparing various restoration mechanisms of marine ecosystems following the P/Tr event in different habitats and climate zones, we will summarise the recovery traits of marine ecosystems and their controlling factors. The quantified features of marine ecosystems during the various recovery stages will enable comparison with modern defaunation events and their aftermath.