Re: Compenstaion Points

Light compensation points for aquatic plants have been measured in the 
range of about 15 to 80 umol/m2/sec PAR (about 1 to 4% full sunlight 
intensity). This is low, which indicates, as Paul mentioned, that most 
submerged aquatic plants are shade plants. Photosynthesis is saturated at 
between 300 and 1000 umol/m2/sec PAR (about 15 to 50% full sunlight). 
There is also a CO2 compensation point for plants ... sorry no data at my 
fingertips. This is more complicated because many aquatic plants can 
utilize bicarbonate.

Dr. dave.