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Thingy Thursday: The Blob

Thursday, December 16th, 2010

You know how images and thoughts evoke emotions or sensations? Well, considering La Nina’s recent fury and the approaching dark of the winter solstice, I figured I’d share a creature that takes me back to the heat and sun of August.

Football-sized Pectinatella magnifica bryozoan colony. Photo: Jeff Adams

One of the more common summertime unknowns (often presented with concern or disgust!) is a freshwater colonial invertebrate called Pectinatella magnifica, the magnificent bryozoan. Magnificent is part of its scientific name, but dragon boogers seemed more appropriate to my 5 year old.

These gelatinous blobs feel kind of like a jellyfish, can grow larger than a basketball and are made up of thousands of tiny individuals living on the surface. At their healthiest, they tend to be a beautiful purple color with hundreds of white-speckled groups of living individual called zooids. These clusters look like snowflakes or rosettes.

Like a jellyfish, much of the blob’s mass is water. In this case, that mass is a non-living part of the colony in which the living zooids are embedded and contribute to its formation. The tiny individual zooids are ecologically similar to corals or hydra, in that in that they have delicate tentacles that they expose to the water and use to capture fine, drifting organic material (the hydra are after tiny animals). They can also pull those tentacles into the protective, non-living body of the colony when disturbed.

Close up of Pectinatella colony and clusters of individuals. Photo: Jeff Adams

These large gelatinous blobs form in warm (>16°C or 60°F) slow or still water (the images to the right and below are from the Columbia Slough in Portland, OR).  Smaller blobs may be free floating, but larger ones usually grow on branches and vegetation. Those growing on plants may also float when plants begin to die off and drift in the late summer and fall. Sometimes, the blobs become so numerous they clog water intakes and requiring 24 hour attention.

By the time vegetation starts breaking down, the colony is probably dying off as well.  However, they leave behind an unusual reproductive structure that can withstand cold, heat, drying, and time. These seed-like statoblasts are a collection of cells inside a protective shell, and they carry on the lineage of the parent colony. The statoblast is formed out of a connection to the parent zooid’s gut and can either cling to the colony or drop to the sediments or be transported to new locations by other wildlife. Each little survival pod can start a new colony whenever and wherever conditions are favorable.

Microscope photo of Pectinatella statoblasts. Each is only slightly larger than the thickness of a dime, but can produce an entire colony. Photo: Jeff Adams

Statoblasts are a specialized characteristic of freshwater bryozoan species. Marine waters are where bryozoans are truly diverse with thousands of ocean dwelling species, while there are only a couple dozen species known in freshwaters of North America. The magnificent bryozoan is certainly the most… magnificent among them.

The magnificent brozoan is classified by the USGS Non-indigenious Aquatic Animal database as a native transplant – native to the warmer water east of the Mississippi and transplanted out west. Though it may have just been widespread and no one gave it much attention. Maybe climate change will allow it to be happier in our usually colder waters?

Now when you take a break from your winter labors, close your eyes and imagine yourself floating on the surface of a warm lake or down a slow river… Please forgive me for the slimey blobs that start bumping up against your imagination, leaving you speckled with statoblasts, and cursing me for having wrecked your perfectly good escape. Happy daydreaming!

Jeff Adams is a Washington Sea Grant Marine Water Quality Specialist, affiliated with the University of Washington’s College of the Environment, and based in Bremerton. You can follow his Sea Life blog, email to jaws@uw.edu or call at 360-337-4619.


The end is nigh

Friday, September 3rd, 2010

School buses aren’t the only harbingers of summer’s end. The last daytime minus tides of 2010 will be over the next four mornings. The tides for Bremerton over the next few days are…

We usually boil Dungenes crabs before we eat them but what the hay. Photo: Jeff Adams

Saturday – 8:00AM, -0.3
Sunday – 9:00AM, -0.7
Monday – 9:50AM, -0.7
Tuesday – 10:40AM, -0.5

What a better way to enjoy a relaxing morning than a walk on the beach. Or maybe you could enjoy a morning shellfish harvest for lunch. Thanks to toxins from plankton (paralytic shellfish poisoning or PSP) and Vibrio bacteria, many of our beaches currently have health department restrictions or advisories. Check the Washington Department of Health Shellfish Safety website before you head out.

Not only are we losing our low tides, most of us in Hood Canal, central Puget Sound and Whidbey Island area are seeing our final days of crab season. Male Dungeness and red rock crabs await the boiler, but you’ll have to catch them first.

Male and female red rock crab (Cancer productus) molts. Photo: Jeff Adams

Sexing crabs is a pretty easy business if you can get them to hold still long enough to turn them over. The abdomen of a crab is one of the things that separates the different groups of 10 legged crustaceans.

In hermit, king, porcelain and related crabs, it’s asymmetrical, somewhat exposed and (in the case of hermits) soft enough to need a shell to keep important organs from becoming fish food. In lobsters and crayfish or even shrimp, the tail is symmetrical and large with powerful muscles.

True crabs, like the graceful, red rock, Dungeness and shore crabs we commonly see on the beach, have a symmetrical abdomen that is relatively flat and tucked snugly under their body between all their legs. The male’s abdomen is narrow, generally shaped like a triangle and only fills a portion of the space between the legs. The female’s is broad, filling most of the space between the crab’s legs. This broad abdomen helps her protect her eggs while she broods them.

Female grooved mussel crab (Fabia subquadrata) loaded with eggs. Photo: Jeff Adams

I hope you had a fabulous summer and were able to enjoy all that water has to offer. Now that autumn is upon us, I hope to be a bit more regular about blogging. There is so much I’d love to share and to learn from you. Thanks and have a great weekend! JEff

Jeff Adams is a Washington Sea Grant Marine Water Quality Specialist, affiliated with the University of Washington’s College of the Ocean and Fishery Sciences, and based in Bremerton. You can follow his Sea-life blog, email to jaws@uw.edu or call at 360-337-4619.


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