SEASONAL-VARIATIONS OF ZOOPLANKTON BIOMASS VERTICAL DISTRIBUTIONS IN THE MESOPELAGIAL AREA OF THE SOUTHERN-OCEAN

Seasonal variations of zooplankton biomass vertical distributions for the depths between 100 and 1000 m in two latitudinal zones (55-65 degr ees and 45-55 degrees) in the Southern Ocean were studied. From 100 to 400 m the amplitude of biomass oscillations decreases abruptly and be come almost constant below 400 m. At a depth of 100 m the biomass valu es change on the order of magnitude in the southern zone, while in the northern zone the values vary by a factor of three during the year. T he phases of biomass oscillations are almost opposite at depths of 100 and 1000 m. Mathematical descriptions of biomass vertical profiles ar e suggested. The possibility of estimation of biomass distributions wa s considered for the periods with low amount of data.