Unknown algae growing in the shaded areas

[FindingNem0]

Only noticed these the other night, got them growing in areas with low light.

 

[FindingNem0]

Bump

 

[taricha]

for sure a green algae of some sort. looks maybe siphonous (one big cell, rather than segmented)
https://cfb.unh.edu/phycokey/Choices/Chlorophyceae/siphonous_greens/siphonous_key.html
(not saying it's exactly one of those listed).

Anyway, look for good herbivores or your life will be hard. Others who've had similar may be able to give you a headstart on herbivore search.