engleski

DISTRIBUTION OF DAPI-YELLOW PARTICLES (DYP) IN THE NORTHERN ADRIATIC

The primary source of organic matter (POM) in pelagic ecosystem is phytoplankton. During the transfer processes of energy and organic carbon within the food web considerable amount of these organic matter is released as dissolved form or transformed into dead matter. DYP are organic, enzyme-degradable matter made mostly of phytoplankton-derived detritus and dissolved organic carbon and are considered as very degraded stage of detrital particulate matter, which is probably the reason why they are so abundant. The scope of this study was to estimate their seasonal and spatial distribution in the area of the northern Adriatic, specially because there are no earlier studies on that problem. A study was conducted from December 1996 to June 1997 within 6 stations. Samples for DYP were stained with DAPI collected on polycarbonate black filters and counted using epifluorescence microscope.DYP where grouped into three different size classes (<2µ ; m-pico, 2-20 µ ; m-nano, >20 µ ; m-micro).This study showed that total abundance of DYP varied between 0, 3-70, 4x107 L-1 with the largest proportion in the size class from 2-20 µ ; m.Statistical analysis showed significant difference between eastern and western stations whith lower abundances on eastern ones. Between southern and nortern stations there were no significant differences. Seasonal distribution showed higher abundance during winter than summer period (max. December 1996 and January 1997, min. July 1997) while vertical distibution reveal that they were more abundant in deaper layers.This study reveals high abundances of DYP in the northern Adriatic and their importance in total particulate organic matter and necessity of their further research.

DYP; Northern Adriatic

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