Bigelow Laboratory for Ocean Sciences

Ocean Life, Planet Health

David Emerson Laboratory

David Emerson Laboratory

In the Emerson Lab we study iron-oxidizing bacteria in marine and freshwater environments. Our work ranges from exploring the community of iron-oxidizing bacteria at the Loihi Seamount, to isolation of novel iron-oxidizing bacteria from marine and freshwater environments, to studying the role of iron-oxidizing bacteria in steel corrosion.

People - scientists working in the Emerson Lab

Research - research topics and projects

Publications - peer-reviewed journal articles relating to the work done in our lab

Links - related links of interest


Overview of Research in the Emerson Lab

Work in my laboratory centers on an aspect of geomicrobiology that has to do with the microbial oxidation of iron. We have discovered several new groups of bacteria that are capable of capturing enough energy to grow by oxidizing Fe(II) (ferrous iron) to Fe(III) (ferric iron). These bacteria are adapted to growing at very low oxygen levels, which is important, because at higher O2 levels, the chemical oxidation of Fe(II) becomes so rapid that the bacteria can no longer compete with it. These Fe-oxidizing bacteria (FeOB) grow and are abundant in freshwater and brackish wetlands, water wells and distribution systems, hydrothermal vents in the ocean, and other marine environments where Fe(II) is present. We have isolates of FeOB from the freshwater iron seeps, the rhizosphere, deep ocean hydrothermal vents, and coastal settings. Highlights of this work include pioneering efforts on the growth and isolation of novel Fe-oxidizing bacteria from both freshwater and marine environments. The discovery of the Zetaproteobacteria, a new class in the phylum Proteobacteria, that has a cosmopolitan distribution around the globe, but, thus far, is restricted to suboxic marine environments with high concentrations of Fe(II). My lab has demonstrated that several of the FeOB are obligate Fe-oxidizers, that is they will not grow on anything but ferrous iron; they contribute substantially to natural iron-cycling in the environment. We have been involved in sequencing the genomes from several FeOB. This latter work has opened up new metabolic possibilities for Fe-oxidizers, and allows more detailed study of their evolution allowing us to delve into the antiquity of these organisms that form unusual mineral structures that are recognized in the fossil record. Recent discoveries include demonstration that FeOB may initiate biocorrosion of steel in the marine environment, and that populations of freshwater and marine FeOB are very distinct, but may have undergone significant convergent evolution to grow on iron.  The work in my lab is funded through the National Science Foundation, NASA, and the Office of Naval Research.

 

Associate Director of the CCMP for bacteria. The Provasoli-Guillard National Center for Culture of Marine Phytoplankton (CCMP) is a world-renowned bioresource center for marine phytoplankton that has been in existence at Bigelow since 1981. It has over 2,500 strains of phytoplankton, primarily eukaryotes, and supplies over 3,000 strains/year to the scientific community. I am helping to expand the CCMP to include marine bacteria and archaea. This important group of microbes includes a very diverse array of heterotrophic and lithotrophic bacteria and archaea. Representatives can grow at both coldest and hottest temperatures for life and use a bewildering number of different substrates for growth. They are of fundamental interest to understanding marine ecosystem processes, in maintaining ocean health, and of commercial importance in biotechnology. If you have a strain you would like to deposit or one you would like to see in the collection please email me (demerson at bigelow.org).