Biologically-Mediated Molecular-Level Transformations of Marine Organic Matter
|Comparison of DOM collected from protozoan (top) and bacterial (bottom) cultures. (Kujawinski et al., 2004 Marine Chem.)|
Although the role of the microbial web in OM cycling in the coastal and open ocean has been well-established, molecular-level understanding of the transformations within different pools of OM has not been possible due to analytical limitations. The study proposed here will examine these transformations using isotope-ratio gas chromatography / mass spectrometry (irGC/MS) and electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS). Laboratory cultures of protozoa, bacteria and/or phytoplankton will be monitored for changes in OM composition as a function of time. The prey cultures will be isotopically-labeled with either C13-acetate (bacterial prey) or C13-bicarbonate (phytoplankton prey). Incorporation of the C13-label from prey material will be tracked through the protozoan digestive process and the lability of different OM fractions within grazing cultures can be estimated. Laboratory results will be extended to the field with incubations of size-fractionated seawater from coastal (NY) and oligotrophic (Bermuda ) environments.
Funding: National Science Foundation; Grant #CAREER - OCE - 0529101
Personnel: Katie Barott (technician); Karin Lemkau (graduate student); Louisa Morrison (technician)
Publications: Kujawinski, E. B. and M. D. Behn. 2006. Analytical Chemistry 78: 4363-4373; Kujawinski, E. B. et al. 2009. Geochimica et Cosmochimica Acta 73: 4384-4399