Energy gathering mechanism in marine bacteria via Proteorhodopsin.
With Pace and his group at Indiana University, DeLong developed a method that can be used to identify single cells phylogenetically through the use of phylogenetic stains.[3] These rRNA-based probes identify the cells based on the binding of fluorescent probes to individual cells through use of oligonucleotides that are complementary to 16S rRNA sequences of specific phylogenetic groups. The use of multiple probes with different fluorescent dyes allows for the identification of different cell types in the same field.
DeLong subsequently expanded upon this work and applied gene cloning and sequencing to the study of complex marine microbial communities and their role in the biosphere. These techniques carried significance in that microbes could be studied without the use of a standard microbial culture.
After receiving an independent study award in 1989, DeLong spent some time at the Woods Hole Oceanographic Institute in Woods Hole, Massachusetts, and would later on become associate professor in the Biology and Ecology, Evolution, and Marine Biology Departments at the University of California, Santa Barbara. DeLong's surveys during his time at UCSB led him to participate in the study of widespread abundance and diversity of marine archaea in the world's oceans. Prior to 1992, archaea were thought only to exist in the extreme environments of hypersaline lakes, hydrothermal vents, and similar places. This changed the general view of the scientific community on the role of archaea in the biosphere and opened up new possibilities in applied potential of such microbial assemblages.
In the years following, DeLong's work took him to the Monterey Bay Aquarium Research Institute and it is during his time there that he made a crucial discovery in the understanding of the Earth's carbon and energy cycles. A team of microbiologists led by DeLong discovered a gene in several species of bacteria[4] responsible for production of the protein rhodopsin, previously unheard of in the domain Bacteria. These proteins found in the cell membranes are capable of converting light energy to biochemical energy due to a change in configuration of the rhodopsin molecule as sunlight strikes it, causing the pumping of a proton from inside out and a subsequent inflow that generates the energy.[5] In 2004, DeLong moved to the Massachusetts Institute of Technology, where he worked on developing gene expression studies targeting microbial communities in the wild. At MIT, his collaborations with CMORE and Monterey Bay Aquarium Research Institute colleagues, he discovered of highly synchronized microbial populations having oscillating patterns of gene expression[6] across many species. In 2014, DeLong relocated to the University of Hawaii, where he serves as co-director for the Center for Microbial Oceanography: Research and Education, C-MORE[7] and the Simons Collaboration on Ocean Processes and Ecology, SCOPE.[8]
In April 2008, DeLong was presented with the Vladimir Ivanovich Vernadsky Medal for “important contributions to geomicrobiology and biogeochemical cycling through the innovative use of molecular tools and a genomic approach” at the European Geosciences Union[9]
The American Society for Microbiology presented DeLong with the Procter & Gamble Award in Applied and Environmental Microbiology in May 2008 and the D.C. White Research and Mentoring Award in February 2009