960 resultados para Light water reactors
Resumo:
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) = 0.0413x**0.628; R**2 = 0.63) and for the red maximum (?_ph(678) = 0.0190x**0.843; R**2 = 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/m**3 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; R**2 = 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; R**2 = 0.95). Relation of a_ph with chlorophyll a concentration was described by a power function (y = 0.0173x**0.0709; R**2 = 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.
Resumo:
Spectra of light absorption by suspended matter, phytoplankton, and detritus in the central and coastal parts of the Black Sea over the spring period (March-April 1995) were determined. Vertical homogeneity of the upper 40 m layer with respect to parameters in study was noted. Value of light absorption by phytoplankton normalized with respect to chlorophyll a was virtually independent of chlorophyll a concentration. A linear relationship between light absorption by phytoplankton and chlorophyll a concentration was established at the red spectral maximum. It is described by the equation y = 0.0153x; R**2 = 0.61. The average ratio of absorption values in the peaks was 2.29. Contribution of detritus to total light absorption at wavelength 440 nm was 23-62% regardless of depth and chlorophyll a concentration.