I pulled this stick, coated with a green slime, out of the water because I wanted to photograph how different it looks, once immersed. It looks like a green blob of jelly when out of the water.
Isn't that an amazing transformation?
I've been struggling to I.D. it definitively, but so far it looks to my untrained algae-eye that it might be the cosmopolitan species commonly referred to as gutweed (Ulva intestinalis), which can form algal 'blooms' in eutrophic conditions and stagnant coves. The filaments are shorter than the literature indicates though, so I would love any help or guidance in identifying this algae.
UPDATE: this is likely the algae called Batrachospermum, according to help given by the Lake Stewards of Maine (LSM)