John Simpson leads a research group in the School of Ocean Sciences at Bangor University in Wales, which is developing new methods to observe and model turbulence and the mixing that plays a crucial role in biological production. He is a seagoing physical oceanographer with a broad interest in shelf seas and estuaries and his research has focussed on the physical mechanisms which control the environment of the shelf seas. He has taught Physics of the Ocean at Bangor and other universities worldwide for more than 40 years and was responsible for establishing the first Masters-level course in Physical Oceanography within the UK. In 2008 Professor Simpson was awarded the Fridtjof Nansen Medal of the European Geosciences Union for his outstanding contribution to understanding the physical processes of the shelf seas and the Challenger Medal of the Challenger Society for his exceptional contribution to Marine Science. Jonathan Sharples holds a joint chair at the University of Liverpool and the UK Natural Environment Research Council's National Oceanography Centre and has taught courses in coastal and shelf oceanography at the universities of Southampton and Liverpool. He is an oceanographer whose research concentrates on the interface between shelf sea physics and biology. His work is primarily based upon observational studies at sea, combined with development of simple numerical models of coupled physics and biology. Professor Sharples has extensive seagoing experience off the NW European shelf and off New Zealand, having led several major interdisciplinary research cruises. His research has pioneered the use of fundamental measurements of turbulence in understanding limits to phytoplankton growth and controls on phytoplankton communities.