It is interesting to note that C. flabelliformis and A. calamus showed significantly higher photosynthetic rates in summer
and at 13:00, whereas the other species showed higher photosynthetic rates in autumn and at 11:00.
Root activity is one of the indicators reflecting root absorption capacity and the strength of root metabolic activity
(Lehmann, 2003). However, we found that root activity was not strongly correlated with ROL. Root activity also showed weak
correlations with nutrient removal. Other research has also indicated that root activity had a weak correlation with nutrient
removal in wetlands (Yang et al., 2004). More work is needed for understanding the roles of root activity in nutrient removal