OLIGOTROPHY AND PELAGIC MARINE-BACTERIA - FACTS AND FICTION

Oligotrophy, or the inability of bacterial cells to propagate at eleva ted nutrient concentrations, is a controversial phenomenon in microbio logy. The exact cause of the unculturability of many indigenous marine bacteria on standard laboratory media has still not been resolved. Un fortunately the physiology of such cells is difficult to investigate a s long as high cell density cultures cannot be obtained. An extensive evaluation of experiments relating to oligotrophy and the cultivation of marine bacteria is presented in this review. When incorporating the findings of studies performed with molecular biological methods, the picture emerges that indigenous marine bacteria can be cultivated unde r certain conditions and that the 'oligotrophic way of life' is a tran sient characteristic. Although strong generalisations should not be ma de with respect to a biological system as diverse as the world's ocean s, it should be anticipated that cells with unique physiological chara cteristics appear to exist in the oceanic system. When combining conve ntional physiological approaches with molecular biological techniques it is feasible to unveil the phenotypes that go with the encountered g enotypes. In view of the enormous complexity of the oceanic system thi s will prove an ambitious, yet resourceful undertaking.