The Oceans at MIT website has a new feature story on Professor Sallie (Penny) Chisholm’s lab, which studies Prochlorococcus, the world’s smallest and most abundant photosynthetic marine organism. Chisholm, who in January received the National Medal of Science, led a team of scientists in the mid-1980s that discovered this tiny ocean microbe. The Oceans’ feature story describes how researchers in the Chisholm lab are now using information from individually sequenced Prochlorococcus genomes to identify Prochlorococcus genes in the rapidly growing common metagenomic database — a library of genes from millions of different organisms. This new approach is yielding very precise ecological information about the microbe and its relationship to its environment.