1 School of Civil and Environmental Engineering and School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA. Electronic address: kostas@ce.gatech.edu.
2 Marine Microbiology Group, Department of Animal and Microbial Diversity, Institut Mediterrani d'Estudis Avançats (IMEDEA; CSIC-UIB), Esporles, Spain.
3 Max Planck Institute for Marine Microbiology, Bremen, Germany.