Abstract |
Techniques have been developed to estimate rates of photosynthesis in macroscopic marine algae by monitoring oxygen production. Attempts to use 14C techniques were unsuccessful, because of the difficulty of recovering assimilated 14C by maceration, acid hydrolysis and strong base solubilization of thalli. Photosynthesis by macroscopic algae was strongly influenced by water movement. Under conditions of standing water, oxygen production decreased to a fraction of oxygen production in a stirred system. The effect of DDT on photosynthesis of Rhodymenia, Fucus and Ulva could not be consistently demonstrated. If any effect did occur, its magnitude was below the level of detection because of the photosynthetic variability among plants. These findings are in contrast to the pronounced effects of DDT on phytoplankton photosynthesis reported previously. |