Andrew J. Watson
The 2004 Fridtjof Nansen Medal is awarded to Andrew J. Watson for fundamental contributions to the understanding of the integrated oceanic system involving both its physical and biogeochemical components.
With a pioneering view, probably inspired by his PhD supervisor, J. Lovelock, Andy always considered the Earth as a single system within which the biosphere, both terrestrial and oceanic, is an active, essential component.
His earlier research activity covered topics related to the impact on the biosphere of forest and grasslands fires, and to the planetary atmospheres of the Earth and Venus. From the early 80’s, by successfully using a variety of complementary approaches, ranging from experimental work, in the laboratory and at sea, to theoretical and numerical modelling, Andy made seminal contributions to understanding the physical and biological controls of the global biogeochemical cycles. Among these was the use of in situ iron enrichment experiments in HNLC areas to provide the proof of John Martin’s “iron hypothesis”. Another breakthrough was in the use of sulphur hexafluoride tracer release experiments to measure vertical diffusivity in deep water formation regions, critical areas for transporting atmospheric carbon dioxide into the deep ocean. He is an outstanding biogeochemist who has advanced global biogeochemical problems with remarkable intuition and great practical know-how.