S-3-1

CHEMICAL ECOLOGY OF MARINE BACTERIA: FIRST INSIGHTS

Paul R. Jensen and William Fenical
Center for Marine Biotechnology and Biomedicine, Scripps Institutionof Oceanography
University of California, San Diego, La Jolla, CA 92093-0236


Marine bacteria are an essential component of the marine environment. Rather than being evenly distributed, various "strains" of marine bacteriaare found in symbiotic, mutualistic and pathogenic associations withall forms of marine plants and animals. Surface bacteria appear tobe highly specific and reflect the unique chemical compositions of thehost surface. Hence, "side by side" organisms commonly do not sharethe same microbial associates. Recent investigations indicate thatbacterial associations are important adaptations for survival. Bacteriafound in association with other organisms frequently produce metaboliteshypothesized to provide defenses against encroaching pathogens. Incomplex, organic-rich marine sediment communities, competition for substrateand nutritional sources may involve inter specific competition throughthe production of antibiotics. The developing picture in marine systemsis that low nutrient environments (oligotrophism) selects for species-specificadaptation to nutrient-rich niches. Examples of early research results,which involve estuarine shrimp, bacteria associated with seaweeds and ascidians,and a study of sediment bacterial communities, provide the foundation forthese hypotheses.