From high latitudes into the tropics: The role of palaeogeography for the biodiversification of Ordovician bryozoans of Baltoscandia

• Applicant: Privatdozent Dr. Andrej Ernst, Ph.D.
• Subject Area: Palaeontology
• Term: from 2018 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 413010093

This proposal intends study of patterns of the spatial diversity of the Ordovician bryozoans of Baltoscandia. After the Cambrian explosion, the Great Biodiversification Event (GOBE) was the second pulse of diversification of the life in the Phanerozoic. The intended study will help to reveal new insights in the processes of biodiversification during the GOBE.The central aim of the project is to identify the role of spatial diversity in the diversification. This study will answer the questions, at which level the biodiversification takes place, which ecological parameters drive it, and how strong is the influence of provinciality and migrations on the biodiversification. Bryozoans are a perfect model group for study of diversity patterns in the Ordovician because they have many advantages including possessing of calcified skeleton in the majority of clades, their modular organisation (strictly colonial), wide distribution in marine biotopes of the Ordovician. They occupied the shelves of Baltica, a palaeocontinent moved from high latitudes towards the tropics during the Ordovician. This drift resulted in a gradual climatic change which certainly affected the diversity dynamics of the benthic fauna, among them bryozoans. The combination of the fast biodiversification of bryozoans and the palaeogeographical shift of Baltica is the beneficial condition to study the temporal and spatial diversity patterns. The study of diversity (alpha-, beta-, gamma-) will be concentrated in two temporal/spatial transects: 1) Darriwilian of Norway, Sweden, Estonia, and NW Russia, and 2) Katian of Norway, Sweden, Estonia, and NW Russia. In addition, palaeobiogeographic patterns of Ordovician bryozoan faunas of Baltoscandia will be studied, in order to estimate the role for migrations in biodiversification processes. In the course of the intended study several hypotheses will be tested. Firstly, it is supposed that biodiversification was strong at the local scale, and isolation played an important role. Secondly, certain ecological factors as substrate type, depth, sediment influx, and probably nutrient support influenced the biodiversification of bryozoans in the Ordovician. Thirdly, large-scaled migration apparently suppressed the biodiversification resulting in the increase of the alpha-diversity (local) but decrease of the beta-diversity (interregional), whereas gamma-diversity (regional) remains without changes. It is expected that the all components of diversity increase during biodiversification events, whereas during mass extinctions separate parts of the global diversity (alpha-, beta-, or gamma-) are affected.

• DFG Programme: Research Grants