PATTERNS OF PHYTOPLANKTON PRODUCTION AND HYDROLYSIS RATE OF NATURAL POLYMERS IN THE BLACK-SEA IN AUTUMN

Primary production in the water column (P-p) and mean values of chloro phyll ''a'' content in the photosynthetic zone (CHL) varied within the following ranges: 100-370 mg C/m(2)/day and 0.46-0.66 mg/m(3) in the central deep regions of the sea; 320-500 mg C/m(2)/day and 0.58-0.87 m g/m(3) in the regions of continental slope; 570-1200 mg C/m(2)/day and 2.7-4.9 mg/m(3) at the north-western shelf. Potential rate of extrace llular enzymatic hydrolysis was estimated from the combined proteolyti c and amylolytic enzymatic activities (EA) in the photosynthetic zone. Values of EA ranged from 210 000 to 370 000 e.u./m(3) (enzymatic unit s per m(3)) at eutrophic north-western shelf and from 14 000 to 100 00 0 e.u./m(3) in mesotrophic deeper regions of the sea. Spatial variabil ity of P-p in the open sea depended largely on fluctuations of insolat ion. It was shown that the autumn changes of vertical phytoplankton di stribution and concurrent decrease of EA started in the western parts of the sea and extended to east gradually. Analysis of photosynthetic light curves points to capability of phytoplankton for rapid light ada ptation during sharp change of weather conditions. Regression analysis has shown positive correlation between EA and the values of P-p, CHL and maximum assimilation number (mg C/mg chl. ''a''/hour).