On a recent trip to Reelfoot Wildlife Refuge we noticed that the Azolla, a floating fern which grows among the duckweed, had turned a reddish-brown color. The leaves of this freshwater aquatic fern really seemed to “pop” when hit by the bright sunlight.
“You stand out like a strawberry in a bowl of peas .” ~Unknown
walking on a country road 
There is another fern, similar, that is an invasive species and can smother a swamp area. We have had some of that hit areas.
I was reading about that while researching Azolla. It doesn’t sound like it would be easy to deal with. The pleuston layer at Reelfoot is made up of duckweed and Azolla (Carolina mosquitofern).
The intrusive weed is also a mosquito fern.
From up top, at a glance it looks like a cranberry bog.
Yes, it really does. 🙂