Besides nudibranchs, there were a few other people from the seashore groups that were there brought in by the low tide today.
Then I happened to see this slug or is it a nudibranch (could it be Phyllodesmium briareum? asks Ria from the blur photo I sent her) and this dude who happened to be there mentioned that it was a slug that could photosynthesize. I can't verify the species but the nugget about slugs photosynthesizing brought to mind an article I read. But first the pictures of this fair creature... I hope this is really a slug of some sort! I thought they were a cluster of mollusc eggs. I am not sure if this slug really photosynthesizes though.
But anyway, more about photosynthesizing slugs! Well they don't really but they do collect the plastids (chloroplasts basically) by feeding on the algae (they one that this slug is feeding on is presumably Bryopsis). Collecting the plastids is already quite amazing since the slugs selectively do not digest this organelle. Another most profound aspect of this ability to harness photosynthetic machinery is a gene that is co-opted by the slug in its co-evolutionary history... so baby slugs are born with one photosynthetic gene that helps maintain the ingested plastids for at least 9 months... cool.
ScienceDaily (Dec. 3, 2008) — The lowly sea slug, “Elysia chlorotica,” may not seem like the most exciting of creatures, but don’t be fooled
“Photosynthesis needs around 2,000 to 3,000 genes, and animals do not have many of the critical genes,” says Manhart. So Manhart and his co-workers looked into how the plastids consumed by the slug can continue photosynthesizing.
“We found that the slug has at least one gene required for photosynthesis in its nuclear genome, which has never been found in any animal,” says Manhart. “The critical thing is the plastids come from the alga, but the slug nucleus contains at least one, and probably more of the genes required for plastid functioning,” he adds.