The maximum electron transfer rate (ETRmax) is a critical
parameter for characterizing the rate of photosynthesis of microbial
aggregates, such as multiple algal communities, and the
state of algal growth [51]. Results showed that the ETRmax
of periphyton in the control treatment fluctuated between
0.205 mol/(m2 s)−1 and 0.379 mol/(m2 s)−1 during the experiment.
The ETRmax after exposure to heavy metal pollution however,
sharply decreased from ∼0.268 mol/(m2 s)−1 in the beginning to