Mak A Saito, Woods Hole Oceanographic Institution, Marine Chemistry & Geochemistry, Woods Hole, MA, United States, Matthew R McIlvin, Woods Hole Oceanographic Institution, Marine Chemistry and Geochemistry, Woods Hole, United States, Qi Chen, Oregon State University, Department of Microbiology, Corvallis, United States, Craig A Carlson, Bermuda Institute of Ocean Sciences, Arizona State University, St. George's, Bermuda and Stephen J Giovannoni, Oregon State University, Department of Microbiology, Corvallis, OR, United States