ABSTRACT
This chapter discusses few specifics on the subtle biotic and chemical factors that regulate a dynamically changing population and community structure. Because of the ephemeral qualities of samples of seawater containing marine microbes and protists, some workers have chosen "black box" approaches to study functional problems. There are many different successful approaches to growing marine protists in the laboratory. Fortuitous/agnotobiotic cultures have the advantages of ease of setup and low-cost maintenance, but they are often unreliable. Some photosynthetic and osmotrophic marine protists are easily isolated in axenic culture, but with others considerable effort is required to axenize them or set up synxenic cultures. Aseptic technique is required to maintain them gnotobiotic. Two methods are commonly used for the isolation of axenic osmotrophs: migration and washing techniques popularized by R. L. Guillard, L. Provasoli, and co-worker and the silicone oil dilution method developed by A. T. Soldo.
