Freshwater Jellyfish?!

Until today I didn’t even know such things existed, but this morning one of the science teachers showed up to work with a jar of water from a local lake containing about four small, live jellies. (I love how every time I’m running out of ideas for a good blog post, the universe provides something awesome!) Getting my camera to take a good photograph of a such a tiny, almost transparent, moving subject proved impossible, so I settled for a short video clip instead.

According to this fact sheet from the USGS, they’re called Craspedacusta sowerbyi and were originally native to China but are now found pretty much throughout the world. However, adult medusae like this (which are only one stage of their complex life cycle) aren’t seen all that often, only in sporadic irruptions. (An irruption is a sudden, sometimes unpredictable increase in population.) It isn’t clear whether they cause any particular problems as an invasive species – they do eat plankton, of course, which could potentially screw with aquatic ecosystems – but they’re harmless to people.

Vilas County, the county in northern Wisconsin where I live, contains more than 1300 natural freshwater lakes, the highest density of lakes found anywhere in the world. That’s literally about one lake for every fifteen people living here. I guess it’s not surprising that with so much freshwater habitat around, we occasionally find weird and surprising things!

[Update: Check out the lengthy comment below by O’fieldstream, who provides a lot more information on these creatures.]

Back to the Beach

I’ll tell you up front that there’s nothing earth-shaking in this post – no massive stranded horseshoe crabs, photogenic cottonmouths, or dead baby dolphins.  But today I did finally go for a walk on the beach for the first time in about a week (finally being sufficiently over my bronchitis to muster the energy), and took my new camera for an initial spin.  My most shocking discovery, actually, was that there were people on my beach!

Okay, so this was hardly the first time I’ve encountered other humans on what is, after all, public land, but there are a lot of people there today – people on bikes, people with buckets of shells, people with beach towels and lawn chairs and umbrellas.  Sigh.  Tourist season is here.

I don’t think I’ve posted any photos of sea cucumbers yet, and there were quite a few washed up today, which slowly expanded and contracted when I poked them – yes, these blobs are living animals, relatives of the sea stars and urchins.  Try explaining to kids that sea cucumber is an animal but sea lettuce is not.

Also lots of dead jellyfish, which are sometimes formless blobs of goo but can sometimes be surprisingly pretty, like little sunbursts at the edge of the waves.

Aaaand now I’m worn out from my walk and tempted to spend the rest of the day inside playing computer games – further proof that I’m not quite over my bug yet.  Ah well.  At least I’m sure I’ll be back at work Monday.

Waves and Sand

I am and always will be a forest person at heart, but that doesn’t mean I won’t miss walking on the beach every day when I leave Georgia.  Ambling along the wrack line, seeing what the waves have turned up today – it’s never the same twice.  The tide will carve a deep runnel midway up the beach…

…only to smooth it out again the next day.

Translucent jellyfish…

…live keyhole urchins, and their remains, which we call sand dollars…

…fist-sized knobs of “sea pork,” a colonial tunicate, which probably resembles our distant ancestors: its tadpole-like larvae have notochords, primitive “backbones” which make this one of the oldest chordate animals.

Eventually my walk takes me to the southern tip of the island, where a mixed flock of sanderlings, dunlins, willets and oystercatchers has congregated at the remains of a shrimp boat that wrecked here decades ago.

I sit on a piece of driftwood for a while, contemplating the view, before returning the way I came.  Not a bad way to spend a sunny Sunday afternoon.