The Global Ocean Sampling Expedition (GOS) is an ocean exploration genome project whose goal is to assess genetic diversity in marine microbial communities and to understand their role in nature's fundamental processes. It was begun as a Sargasso Sea pilot sampling project in August 2003; Craig Venter announced the full expedition on 4 March 2004. The two-year journey, which used Craig Venter's personal yacht, originated in Halifax, Canada, circumnavigated the globe and terminated in the U.S. in January 2006. The expedition sampled water from Halifax, Nova Scotia to the Eastern Tropical Pacific Ocean. During 2007, sampling continued along the west coast of North America.