1988/01/01 by R.L. Oliver, Rod L. Oliver, G.G. Ganf +1
Environmental Science · #Aquatic Ecosystems and Phytoplankton Dynamics #Water Quality Monitoring and Analysis #Water Quality and Pollution Assessment
paper · doi:10.1093/plankt/10.6.1155
In situ light measurements were used to obtain information on inherent and apparent optical properties. The average vertical attenuation coefficient Kd (ave) varied from 1.1 to 4.6 In units m −1 During three periods the variation in Kd (ave) correlated with changes in chlorophyll a concentration and specific attenuation coefficients Ks , of 0.013, 0.014 and 0.022 m 2 mg Chl a−1 were calculated. Chlorophyll-specific diffuse absorption coefficients (A,) for these periods were 0.012. 0.013 and 0.017 m 2 mg Chl a−1 and only varied significantly from estimates of Ks in the period when scattering was intense. Absorption coefficients a (z mid ) and scattering coefficients b (z mid ) calculated for the mid-point of the euphotic zone ranged between 0.45 and 2.9 m and 3.5–52.0 m respectively. Chlorophyll-specific absorption coefficients Ka , of 0.005, 0.006 and 0.007 m 2 mg Chl a −1 and scattering coefficients Kb of 0.05. 0.09 and 0.191 m 2 mg Chl a−1 were measured during the three periods. The high Kb value occurred when gas-vacuolate cyanobactena were dominant. Algal photosynthesis and light absorption were related through the maximum quantum yield φ m which varied between 0.019 and 0.11 mol C Einstein −1 while average quantum yields φ a , varied between 0.006 and 0.024 with a mean of 0.013 mol C Einstein −1 A comparison of changes in the mean irradiance of the mixed zone and chlorophyll concentration indicated that growth was light limited below 0.04–0.05 Einsteins absorbed mg Chl a−1 day −1 .