FNR 45400 Lecture 7: Marine Bacterial Populations
13 Feb 2019
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2. 6 key organism groups in oceanic microbial food web: Planktonic microbe communities are very diverse both taxonomically (phylogenetic) and ecologically (in terms of how they function and process organic material). The functional groupings of planktonic microbes is based on size (indicated range of prey) and the energy pathway (autotrophic vs. heterotrophic) utilized. The two major groups for classifying functionality in planktonic microbes are organotrophs and nitrifying chemolithotrophs. Organisms from the domains eubacteria and archaea are dominant among these two major physiological groupings. Organotrophs are primarily responsible for processing non-living organic material. In the gulf of mexico, hypoxic areas called dead zones exist (fig. These are areas where the phytoplankton have over-exhausted nutrients in that area and have died leading to little to know oxygen production occurring. Organotrophs flock to these sites to process this organic material, which in turn further depletes the oxygen available. Organotrophs also use energy for growth from respiration of organic material and are heterotrophic.
