Benthic (bryozoan) response to Silurian climatic changes

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The Silurian is a time of pronounced perturbations of the global carbon cycle, expressed as strong positive delta 13C excursions with amplitudes of more than 4 permill (up to >10 permill). These changes in carbon isotope values coincide with changes in other parameters such as oxygen isotopes, sea-level, depositional environments, but also with faunal turnovers and extinction events. The steering mechanisms of these events are poorly understood. Nevertheless, these biotic events are well documented for planktic and nektobenthic organisms such as graptolites, conodonts, or hemipelagic trilobites, but very little is known if and how shallow-water sessile benthic organisms react to these perturbations. In this project Silurian bryozoans from Baltica and Laurentia will be investigated with respect to taxonomy, diversity, and biometry. Besides, it will be investigated whether their shape, size, or wall thickness show spatial and/or temporal changes which would allow for palaeoenvironmental interpretations such as changes in nutrification or carbonate saturation of the sea water.