Algae and medusae

Spring is still lagging behind, predictably. I went out this morning to find Crepidula eggs to hatch for experiments, and although the eggs are there, they aren't anywhere near hatching. So back to waiting and trying to farm eggs in the lab.

Stuff is definitely happening in the field, though. Most notable since my last trip was a serious explosion of macroalgae. This site is full of really thick growths of large algae through the late spring and early summer, until it gets really hot. The algae is sort of a pain -- it's probably two inches deep to wade through and covers the snails that I'm looking for. At least I was out in boots today, because walking through two inches of algae in my sandals is a little icky.

A thick bed of algae on the beach. Normally there's just sand and small cobbles here.
The small 'creek' that has been created by flowing water allows you to see just how thick the mat is.

I did find some snail eggs from other species, including this nifty sand collar.

A sand collar, or moon snail egg mass.

But by far the coolest thing I saw today was a jellyfish (species unknown). I noticed something funny-looking floating in ALL OF THE ALGAE and at first I just thought it was a dead Chondrus or something. Lots of the algae turns white when it dies. But this seemed to be weirdly radially symmetrical and, upon further inspection, to have tentacles.

Lucky I had my rubber gloves, because I do usually draw the line at handling unidentified jellies.

Jellyfish!

I was surprised to see this guy so early in the season. The jellies get super-abundant around here by August, but are pretty rare in May. It's also unusual at this particular site to see them washed near shore, though other places I work they are pretty common.

Scyphozoan jellies have a totally awesome life cycle. It has two basic stages: the medusa form (think typical jellyfish) and the polyp form (think sea anemone, to which they are related). A medusa makes gametes that turn into a larva, which grown into a polyp, which then buds into little medusae. Sound complicated? It sort of is. Here's a picture to help.

Life cycle of a scyphozoan. Photo from Wikipedia, with more details.

My favorite part of this life cycle is strobilation, step 11 in the figure above. Here's a fabulous video. And another one. Something that doesn't come across in the not-to-scale diagram but does in the video is just how small the polyps and strobilae are. They really are fascinating. I haven't ever seen a strobila in the field, but it's on my invert life-list.

For today, though, I'll settle for an adult scyphozoan. And maybe some larval Crepidula, if that's not too much to ask for.

Today's jelly, adrift in the algae.