THE RELATIVE ABUNDANCE AND SEAWATER REQUIREMENTS OF GRAM-POSITIVE BACTERIA IN NEAR-SHORE TROPICAL MARINE SAMPLES

The relative abundance of gram-positive bacteria in a variety of near- shore marine samples was determined using the KOH method. Gram-positiv e bacteria accounted for 14%, 25%, 31%, and 12%, respectively, of the colony-forming bacteria obtained from seawater, sediments, and the sur faces of algae and invertebrates. A total of 481 gram-positive strains were isolated representing a wide range of morphological groups inclu ding regular and irregular rods, cocci, and actinomycetes. Seventy-sev en percent of the strains characterized did not form spores and were a erobic, catalase-positive rods with regular to irregular cell morpholo gies. Eighty-two percent of the strains tested showed an obligate requ irement of seawater for growth. None of the cocci tested required seaw ater or sodium for growth. This is the first report documenting that g ram-positive bacteria can compose a large percentage of the culturable , heterotrophic bacteria associated with the surfaces of tropical mari ne algae.