STRUCTURAL AND FUNCTIONAL PECULIARITIES O F MARINE ECOSYSTEMS IN SHALLOW-WATER ZONES OF GASOHYDROTHERMAL ACTIVITY IN WESTERN PACIFIC-OCEAN

Novel data on gasohydrothermal ecosystems in shallow water of the isla nd bulges in the South-Western part of Pacific Ocean has been briefly outlined. The main features or the physicochemical conditions in the z ones of influence of gasohydrothermal flows were considered. Active ph oto- and chemosynthesis (up to 3 and 150 g of C per m3 per day, respec tively) was detected in the pelagial, and joint going of these process es was noted in the surface layer of the bays. Development of bacteria l and algal mats and accumulation of invertebrates was observed in the bottom vents zones saturated with hydrogen sulfide. Pogonophorans wit h methane oxidizing endosymbiotic bacteria were found it methane-rich gasohydrothermal vents at 60-degrees-C. The duration of gasohydrotherm al activity and low water exchange determine the composition and densi ty of populations of the communities.