Setting sail: Sorcerer II is heading out to sea again. Credit: J. CRAIG VENTER INST.

Scientists from the J. Craig Venter Institute have reboarded the research sloop Sorcerer II to sample microbes from the Baltic, the Mediterranean and the Black seas. The microbes will be frozen and sent back for DNA sequencing at the institute's labs in Rockville, Maryland, and San Diego, California.

Craig Venter and his colleagues have already circled the globe to collect open-ocean microbes (see Nature 446, 240–241; 2007). The new voyage, which commenced on 19 March, will "give us substantially more diversity than we find in the open oceans of the world", says Venter.

Flanked by dense human populations, the three seas are likely to paint a portrait of human effects on microbial populations, he says. The project is expected to cost around US$10 million and will be funded by the Beyster Family Foundation in San Diego, with additional grants from-anonymous donors and Life Technologies, the biotechnology company formed from the merger of Invitrogen and Applied Biosciences.