Composition of Exopolymer Particles Produced By Marine Diatoms
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Microbial processes in the sea are an essential component of the Earth’s biosphere. Planktonic microorganisms constitute the majority of photosynthetic primary producers in the ocean in terms of both abundance and biomass. Planktonic photosynthetic microorganisms (phytoplankton) fix approximately half of the organic carbon on Earth and therefore an understanding of the fate of that carbon is essential to understand the functioning of the Earth. Impacts of finding great amounts of DNA not enclosed in a biotic organism could heavily impact species differentiation in the ocean. Exopolymer particles are excreted by phytoplankton, including diatoms. These particles are understood to contain carbohydrates and protein that can potentially serve as a food source to bacteria in the surface of the water column, also impacting the marine organic carbon cycle. This study explored the composition of the exopolymer particles produced by marine diatoms with the aid of dyes, fluorescent stains, and in the future, lectins. My central hypothesis was that marine exopolymer particles have a complex heterogeneous polymeric structure containing polysaccharides, proteins and extracellular nucleic acids. Preliminary results show that DNA is part of diatom’s exopolymer carbohydrate particles and the hypothesis was proven correct, but the results from the experiment were affected by many other factors. This decreases the confidence for the results. Results also show that protein particles do contain acid polysaccharides but that the polysaccharides that make up TEP do not contain lots of glucose and mannose, derived from staining using concanavalin A-FITC. There is reason to believe that the acidity of the Alcian Blue affected the results of the abundance of glucose and mannose in the TEP samples however.
Hinson, Audra (2013). Composition of Exopolymer Particles Produced By Marine Diatoms. Honors and Undergraduate Research. Available electronically from