Distribution, Nutrition, Physiology and Phylogenetics of Oligobacteria

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Button 9316731 A rather even distribution of bacteria occurs in the world's oceans. They recycle a large fraction of the organic material to CO2, leaving a very dilute organic mixture, and send an unknown fraction up the food chain. Their adaptation to the dilute solution results in cellular properties that set them apart from organisms commonly cultured from the sea. These properties include small size necessitating special methods of observation, the ability to subsist in very dilute conditions suggesting the name oligobacteria, and resistance to cultivation. The development of a number of new methods is at the stage where scientists can now applied them to these typical oligobacteria: (i) dilution culture for isolating members of the population and determining their viability, (ii) population structure in sea water for estimating in situ growth rates, (iii) high resolution flow cytometry for quantifying their populations, evaluating their biochemistry, and determining their 3-dimensional distribution, (iv) phylogenetics for taxonomic evaluation, and (v) kinetic theory for interpreting the results. The overall objective of this project is to describe the balance between the concentration of dissolved nutrients and the organisms that affect nutrient concentrations through selective removal. To understand how oligobacteria regulate the concentration of organic nutrients, Dr. Button plans nutritional, kinetic and biochemical studies on isolates. Integrated in these studies are experiments to produce dense cultures to learn how dilute organic solutions regulate maximal marine populations. In addition, the project will investigate using freshly collected sea water the range of growth rates and organism characteristics that one considers common, in order to refine concepts of viability and to evaluate the effect of grazing on bacterioplankton characteristics. ***