Molecular monitoring of picoplankton: Towards in situ analyses
Lead Scientist/Project Manager: Ed DeLong
Lead Engineer: Farley Shane

Single-celled microbes are the most abundant organisms in the worlds oceans. At concentrations of about one million cells per milliliter in surface waters, microorganisms consume an estimated 20-50% of marine primary productivity. Prokaryotic microorganisms are also biochemically versatile, mediating most of the key chemical transformations of carbon, nitrogen, and sulfur in the oceanic biosphere. The cycling of the elements in the sea is absolutely dependent on microbes, but the identity, variability, and activity of these organisms are poorly characterized, and difficult to measure. Our primary objective is to develop new approaches and procedures, using molecular biological and other methods, to rapidly and efficiently identify and quantify marine microorganisms in surface waters and the deep-sea.

Our current field studies focus on characterizing planktonic microbes, but also extend towards characterization of microbes critically involved in cycling of methane at seep sites.

The project involves collections on mooring CTD surveys, to gather synoptic data on the microbial communities and their environment, and provide material for further development of methods and protocols to analyze microbial community structure/function. Development of in situ incubation chambers, to be deployed from moorings or on the sea floor, are another component of this project. We have also begun analyses of microbial populations critically involved in anaerobic methane oxidation at methane seep sites. Instrument development associated with this project involves construction and field testing of an in situ tangential filtration device, for collecting and concentrating large volumes (500 liters) of seawater, for microbial analyses.