Epiphytic bacteria on the brown algae Fucus vesiculosus Linnaeus, 1753 (Barents Sea)

Brown algae in symbiotic relations with epiphytic bacteria play an important role in the bioremediation of the marine environment after the ingress of petroleum products; therefore, the study of these groups of organisms in the habitats with different pollution levels is of importance. The aim of the investigation was to study the structure of the surface of the brown algae Fucus vesiculosus and the localization of epiphytic bacteria on it in clean (Zelenetskaya Bay, East Murman) and oil-polluted (Kola Bay, Murmansk Seaport) water areas of the Barents Sea by the methods of scanning and transmission electron microscopy. To determine the number of cultivable heterotrophic bacteria, we chose the method of using liquid nutrient mediums. It was shown that most of the bacteria in the epiphytic community are concentrated in the natural “hollows” of the surface. On the surface of the algae from the polluted water area, bacteria are also localized in the mucous layer of plants, on the film and under the film of petroleum products, that covers the thallus. Besides the heterotrophic bacteria, a large number of cyanobacteria were found on the surface of algae from oil-polluted areas. It was shown that the number of cultivable bacteria on the surface of algae in the polluted area was more than 17 million cells per cm². In the clean water, the number of epiphytic bacteria reached 14.5 thousand cells per cm². The number of cultivable epiphytic hydrocarbon-oxidizing bacteria in the oil-polluted water was up to 17.4 thousand cells per cm². In the clean water, bacteria of this group were not detected.