p. 81 - 86 THE USE OF 14C METHOD BY LIQUID SCINTILLATION COUNTING FOR ESTIMATING PLANKTONIC PRIMARY PRODUCTIVITY OFF THE ROMANIAN BLACK SEA COAST 1) A.S. Bologa 2) and P.T.Frangopol 3) 2) Romanian Marine Research Institute Constanta 3) Institute of Physics and Nuclear Engineering Magurele-Bucuresti Abstract Preliminary resultats by 14C method, using liquid scintillation counting, on planktonic primary productivity off the Romanian Black Sea coast during July, 1977 (238-825 mg C m-3day-1) are presented.