Marcus is a paleoecologist based at GNS Science, Lower Hutt, Aotearoa-New Zealand. His research focuses on reconstructing historic and prehistoric environmental change through the analysis of sediment cores taken from lakes and wetlands. This work allows insight into how ecosystems and environments have responded to climate change, landscape evolution and human impact. His research interests include reconstructing records of climate and environmental change to provide a context for understanding current and future change and  defining pre-human ecological baseline conditions from lakes to guide restoration and conservation.