Bio-optical characteristics of phytoplankton have been observed during two-year monitoring in the western Black Sea. High variability in light absorption coefficient of phytoplankton was due to change of pigment concentration and chlorophyll a specific absorption coefficient. A relationships between light absorption coefficients and chlorophyll a concentration have been found: for the blue maximum (a_ph(440) = 0.0413x0.628; R2 = 0.63) and for the red maximum (?_ph(678) = 0.0190x0.843; R2 = 0.83). Chlorophyll a specific absorption coefficients decreased while pigment concentration in the Sea increased. Observed variability in chlorophyll a specific absorption coefficient at chlorophyll a concentrations <1.0 mg/m3 had seasonal features and was related with seasonal change of intracellular pigment concentration. Ratio between the blue and red maxima decreased with increasing chlorophyll a concentration (? = 2.14 x-0.20; R2 = 0.41). Variability of spectrally averaged absorption coefficient of phytoplankton (a'_ph ) on 95% depended on absorption coefficient at the blue maximum (y = 0.421x; R2 = 0.95). Relation of a_ph with chlorophyll a concentration was described by a power function (y = 0.0173x0.0709; R2 = 0.65). Change of spectra shape was generally effected by seasonal dynamics of intracellular pigment concentration, and partly effected by taxonomic and cell-size structure of phytoplankton.

Supplement to: Churilova, T Ya; Berseneva, G P; Georgieva, L V (2004): Variability in bio-optical characteristics of phytoplankton in the Black Sea. Translated from Okeanologiya, 2004, 44(2), 208-221, Oceanology, 44(2), 192-203