PhD: Palaeobiology of late Ediacaran microbial substrates

Importance of the area of research concerned:
The Ediacaran Period (635-541 Ma) witnessed some of the greatest evolutionary events in Earth history, including the appearance and diversification of complex macroscopic life. The resulting interactions between early macroscopic organisms and the microbial communities that had dominated the previous three billion years of Earth history ultimately led to the development of Phanerozoic-style marine ecosystems. Determining how the first macroscopic organisms, including the iconic Ediacaran biota, interacted with microbial matgrounds is a relatively poorly studied area. We hypothesise that microbial communities were just as susceptible to environmental factors as macroscopic organisms; that they could influence the ecology and distribution of Ediacaran macroscopic organisms; and even that they likely structured the earliest macroscopic communities. Ediacaran localities in the White Sea region of Russia offer a perfect field area in which to characterise and disentangle these relationships in a variety of sedimentary facies and palaeoenvironments.

Project summary :
This project is designed to establish a new direction in geobiology through the integrated study of an interplay between microbial communities and macroscopic organisms in late Ediacaran ecosystems. It will examine multiple bedding surfaces at classic fossil localities along the Summer and Winter Coasts of the White Sea, Russia. These sedimentary successions contain multiple lithologies, many of which yield exquisitely preserved Ediacaran fossils. The project will characterise the fine-scale, bed-by-bed sedimentology and palaeontology of the sequence, and will attempt to test existing hypotheses regarding the role of microbial surface communities in the nourishment, stabilisation, and preservation of Ediacaran fossils.

What will the student do?:
The student will undertake two 4-6 week field seasons on the White Sea coast of Russia, working on either river or coastal cliff sections. They will produce sedimentary logs of the sections at multiple localities and scales; characterize and collect specimens of microbial mat surfaces for geochemical, petrological, and microfossil analyses; and document spatial relationships between microbial surfaces, sedimentary facies, and associated Ediacaran macrofossils. Samples will be analysed either at the University of Cambridge, or at IPGG in Novosibirsk. A primary aim of the research is to document the variation in microbial communities between different late Ediacaran sedimentary facies, and to identify ecological relationships between microbial surfaces and macro-organisms.