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Upper ocean biogeochemistry

Molecular microbial biology
Project Manager: Ed DeLong
Lead Scientist: Lynne Christianson, Peter Girguis
Lead Engineer: Farley Shane, Ed Mellinger


Microbes critically impact and mediate nearly every major biogeochemical cycle on Earth. Microbial interactions that occur on the scale of microns can regulate global ocean processes on planetary wide scales. Although general procedures to detect, identify and functionally characterize and quantify microbial species and their activities in the marine environment are improving, they are still relatively crude, and lack resolution and sensitivity. 

This project will continue the development and refinement of new approaches to qualitatively and quantitatively describe microbial species and their activities in the marine environment. We will extend the development and implementation of novel genome-enabled technologies, to better characterize microbially mediated biogeochemical processes. New methodologies will be coupled to MBARI-developed platforms and systems for sampling and measurement throughout the water column, and in the benthos. Specific focal areas include determining the relative significance of newly discovered marine phototrophs, which use either rhodopsin-based or bacteriochlorophyll-based photosystems. In addition, we plan to better characterize the poorly understood planktonic archaea, that comprise 20% of all the microbial cells in the ocean, and have recently been implicated in CO2 fixation in the deep sea. In the benthos, we will further characterize those microbes responsible for anaerobic methane oxidation, a microbial process that cycles large amounts of methane in anaerobic marine sediments, and fuels chemosynthetic communities at methane seeps. We plan also to begin, with MBARI and other colleagues, the study of microbial species and processes at hydrothermal vents. Our general developmental areas of focus for this project include:

  1. Conversion of the PISUS (Picoplankton in situ Ultrafiltration System) pump motor from the ROV Ventana's hydraulic power to an electric power source.
  2. Refinement of high sensitivity techniques to quantify and map marine microbial species in space and time.
  3. Development of novel activity assays using genome sequences recovered from Monterey Bay microbes.
  4. Development of new approaches for constructing gene expression libraries, to identify and characterize important biogeochemical processes as they occur in the water column.
  5. Development of benchtop and in situ incubation systems to characterize microbial communities and activities at methane seeps and hydrothermal vents.