Yellow Slime Stuff

[Cap'n]

Just moved some rocks around and found a bunch of pale yellow, slimy, algae stuff on the back of one rock. It is easy to pull the longer sections off but most everything is left behind. It was in a spot of low flow so I moved the rock out with the algae-stuff exposed so I could see if it will deteriorate. There was a bit on the neighbouring rock where it has spread.

Anyone know what this might be or where I could find some pictures to possibly identify?