Charlotte's PhD examines the inter-relationships of terrestrial and marine environments, the resilience of ancient ecosystems to major environmental change, and variations in response to external climatic drivers in low and high latitudes during Earth's most evolutionary dynamic time, the Devonian (416-359 Myr).
The Devonian is known as "the age of fishes" after their extraordinary diversification, and also saw the development of the first ‘modern’ ecosystems on land. Thus, the evolution of roots, wood and seed had profound effects on physical and chemical weathering processes, leading to the establishment of an oxygen rich atmosphere suitable for animal respiration and a marked increase in marine vertebrate body size. These changes to Earth's biosphere culminated in one of its greatest extinctions, in the Late Devonian. This ecological crisis is well known in the marine realm, where the loss of 57% of genera coincides with a globally widespread ocean oxygenation crisis. The Late Devonian Extinction event is poorly understood on land, but the contemporaneous diversification of plants has been proposed as the cause because of enhanced weathering and nutrient runoff affecting ocean chemistry by altering the oceanic carbon cycle.
There are strong parallels with modern global change, and the Devonian provides a wonderful case study for understanding how these processes are affecting life today.