Jochen Brocks, from the Research School of Earth Sciences at the Australian National University, calls his field of research 'Paleobiogeochemistry' as he is fascinated by biological processes in deep time from the origin of life to mysterious ecosystems in Earth's earliest oceans, and events that may have spawned the evolution of complex multicellular life. To find clues about ancient ecosystems, he studies molecular fossils of biological lipids (biomarkers) that can be preserved in sedimentary rocks for billions of years. Currently he and his students investigate the question why large, multicellular and active creatures appeared on Earth some 600 million years ago, and whether ancient oceans harbored a lost world of complex life that left no traces … possibly apart from a few obsolete molecules.