Biofilms: The good, the bad, and the slimy

1. Bacteria floating in the ocean use quorum sensing to aggregate into tightly packed, highly organized, and usually slimy communities called biofilms, which attach to hard surfaces such as ship hulls. The U.S. Navy spends more than $100 million every year on fuel to overcome drag on their vessels caused by biofilms. (Photo by Jim Canavan, Woods Hole Oceanographic Institution)