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PARTICULATE ORGANIC CARBON AND THE VERTICAL
LIGHT TRANSMISSON IN THE ROMANIAN INSHORE
EUTROPHIC WATERS 


Pia Elena Mihnea 
Romanian Marine Research Institute Constanta 


Abstract
The paper is dealing with the interrelation between 
phytoplanktonic community and vertical light transmision in
a marine eutrophicated area. Monthly observations from April
to October 1984 on the 5, 10 and 20 m contour line at agreed
depth have been performed along the Romanian marine inshore
waters. It was concluded that the vertical light transmission
was mainly dependent on the particulate organic carbon than 
the suspended matter, The 50 to 1% isolumes were related to
the stage of the phytoplanktonic species succesion: the heavy
bloom that occured in April and May have implied big biomasses:
143.4-1,144.4 mg C m-3. These biomasses have reduced the mean 
depth of the 50 to 1% isolumes at 3 to 4.5 m. The smaller 
biomasses in June (3.0-209.7 mg m-3) have enlarged the 1% isolume
mean depth: 5-20 m. The great quantities of the suspended matter
(200 mg 1-1)but reduced quantities of particulate organic carbon
(12.8-20.1 mg C m-3) could not determine the depth limitation
of the euphoric layer (10.5 m). In an eutrophicated marine
environment the vertical light transmission is related to the
distance, flux and rates of the waste waters outfalls and 
finally to their eutrophication effects on the sea water.