Supervisor: Nick Butterfield (Earth Sciences)
Importance of the area of research:
Lakes host one of the planet’s major biomes, with constituent organisms providing a diagnostic account of local ecology, environment and climate. The fossil record promises similar insights into ancient systems, but is deeply compromised by differential preservation and search-image. Using a novel acid extraction procedure, we have recently identified an extraordinary assemblage of ‘small carbonaceous fossils’ (SCFs) in the early Miocene Clarkia beds of northern Idaho. The unprecedented diversity, quality and abundance of these 15 million-year-old fossils allow direct comparison with modern counterparts, and present a unique opportunity to assess ecosystem structure on evolutionary time scales.
The Clarkia biota preserves an unprecedented diversity of aquatic crustaceans, mites and larval insects, alongside terrestrial insect, fungal and plant remains. This project will focus on the extraction and biological analysis of individual taxa in the first instance, but with an eye to reconstructing larger-scale interactions and community structure – based on detailed comparison with modern systems. Incorporation of data from broadly comparable biotas in Germany and western Canada will yield an overview of temperate lacustrine ecology through the past 60 million years.
What the student will do:
The student will conduct one season of field work in Idaho in order to document the stratigraphic and palaeoenvironmental context of fossiliferous horizons, and to collect additional samples. A shorter trip, to the Eocene Messel biota in Germany, is planned for the second year. Laboratory work will focus on the gentle extraction/isolation of carbonaceous fossils, followed by anatomical and ultrastructural analysis using conventional light microscopy, SEM and TEM. Full reconstructions of cladoceran crustaceans, chaoborid and chironomid (midge) larvae, ephemopteran (mayfly) larvae and oribatid mites will be used to assess microevolutionary changes in these taxa over the past 15 million years. Trophic interactions and larger scale community dynamics will be reconstructed by integrating these aquatic forms with co-occurring insects, plants and fungi – in the context of modern lacustrine ecology. A combination of ecological and sedimentological signatures will resolve local palaeoenvironment, allowing useful comparison of the Clarkia ecosystem with other fossil biotas.
Please contact the lead supervisor directly for further information relating to what the successful applicant will be expected to do, training to be provided, and any specific educational background requirements.
Butterfield, N.J., Harvey, T.H.P. 2012. Small carbonaceous fossils (SCFs): a new measure of Paleozoic palaeobiology. Geology 40:71–74.
Smiley, C.J., Rember, W.C. 1985. Physical setting of the Miocene Clarkia fossil beds, northern Idaho. Pp. 11-31 in Smiley, C.J. (ed.), Late Cenozoic History of the Pacific Northwest; American Association for the Advancement of Science, San Francisco.