Comish,Seems like the longer we go through winter without snow cover the more spirogyra algae we see.It thrives in cold clear water in midwest ponds. It seems to run in cycles as I believe it is sunlight related. Even when we test phosphate (PO4)as P and get a reading of <0.01 mg/l ,very very low we still see spirogyra as it requires very little P. I also see it in ponds where it has not been a problem in the past once amurs >grass carp< are stocked as the P level goes up as the oxygen producing,nutrient removing plants, "weeds to some" are eliminated. Another example is when chara is controled a lot of the times it is replaced by FA.As spirogyra fades out in the summer it is often replaced by lyngbya or other look alike FA's.
