The Daily Bucket is a regular feature of the Backyard Science group. It is a place to note any observations you have made of the natural world around you. Birds, bugs, moss, butterflies - you can report anything of interest going on in your natural neighborhood. All we ask is that let us know where you are located, as close as is comfortable for you.
Seattle. April 1, 2014.
The Wetland is tiny, perhaps one and a half city blocks wide and two blocks long. It sits on top of the ghost of a wetland that died about a century ago when the Montlake Cut was competed and the water of Lake Washington flowed down to equilibrate with its cousin, Lake Union.
What was left of this and other orphaned Lake Washington wetlands is described in photos from that time as "rank vegetation", trash places, places needing to be utilized in some way. Many of these were filled with the garbage of a growing city. This one just sat, a neglected part of an neglected neighborhood, until 1999, when a private foundation saw through the neglect and imagined a neighborhood rejuvenated as it was reunited with its natural history.
April 1, 2014. The Wetland Pond, looking north.
The Wetland Pond holds everything in the restoration together. It, too, is tiny, perhaps a hundred feet at its widest, just a shallow depression dug into the muck and allowed to fill with upseeping from the water table and rainwater from above. A winter creek fills when the rains come, flowing north into the lake. Mallards gather here every winter, sometimes 50 or more, courting and dabbling. It has never been a clear pond.
During the first summers, when the restoration was young and the alders surrounding the pond were only the size of three or four humans stacked one on top of the other and there was no shade and the sun beat down on the trapped water there were spectacular algae blooms. Thick mats of green, and then red and sometimes iridescent blue.
June 27, 2006. The Wetland Pond, looking north.
The Alders grew, way higher than four stacked humans. The volunteers from the private foundation planted aquatic plants in the pond shallows - Wapato, and others that I haven't been able to identify.The algae blooms quieted, and the pond began to support new life communities.
Pacific Chorus Frogs and Bullfrogs breed here now, as well as at least five species of dragonfly, and insects that skim across the surface of the water, and insects that tumble just underneath the surface of the water, and odd little aquatic worms that wave from their nests under the collected duff at the pond bottom. I knew that there was more. I just needed to be able to see it.
More under the clot of orange algae -->
I bought a microscope at the end of last year, a retirement gift from my colleagues. Now I can see what's going on underneath the surface of Wetland Pond. My notion is to collect water from the pond once a month, and to keep track of what's happening there.
The first collection was on March 18, 2014, from the shallows of the north edge of the pond. You can see the location at the far edge of both of the images above. I swirled up the rotting duff from the pond bottom and skimmed the murk into a container, maybe two ounces.
The water was cool at 49 degrees F. There wasn't much to see under the microscope that evening, just brown debris and a maybe a couple of shreds of what might be green algae. (Please chime in if you can identify this. I need all the help I can get.)
March 18, 2014. Unidentified stuff in water from the Wetland Pond.
I figured on trying again the next morning, but never got to the microscope. There was wiggling in the collection container. Big wiggles. Big enough that I could use the macro setting on my camera to get a picture through the surface of the container.
March 18, 2014. The Creature from the Wetland Pond
Ignore the thing that looks like an eyebrow or antennae. It's just a bit of debris on the side of the collection jar. But do look at the cleverness of this creature's anatomy - the two tiny bubbles of air supporting its shoulders and hips, the primitive eye spot inside a membrane surrounding its head, the faint fish-like fins projecting from the lower part of its posterior, the two little hairs at the very end of its posterior that you can't see as they whirl around, and what might be a digestive tract.
So what is this creature? A Google image search for "aquatic insect larvae with air bubbles" turned up a lovely line drawing that looked similar, and at least a genus name: Chaoborus.
"The 'phantom larva' of the midge Chaoborus (Corethra) (Chaoboridae)" - (Sorry, but you'll have to go to Google image to see this illustration. I thought it was open source, but was mistaken. The original source is the first one listed in "sources" at the end of this essay. Scroll way down to Figure#7. Note that the caption on the Google image is incorrect.)
Have you ever looked out over a stand of fresh water and seen a rising flurry of hovering insects? Those are the adult form of this creature, sometimes described as "phantom midges". By that time they're not long for the world, maybe ten days or so. Most spend the greater part of their lives under water, some even overwintering in the form of the larval individual I happened to catch on my first collection. For obvious reasons, these larvae are also known as "glassworms".
Chaoborus larvae are ferocious predators. My image is too blurry to make out the mouth parts, and though the line drawing is a bit better, neither quite show the detail of this little guy's jaws. Nor do either show the prehensile antennae that are able to grasp their prey, crunch it up and pull it into their mouth. They eat everything available: plankton, daphnia, mosquito larvae, and other larvae of their own kind. In turn, they are eaten by fish, frogs, birds, and other aquatic predators.
At first I wondered if the air bubbles were a breathing device, but it turns out that Chaoborus larvae are able to breath through their skin. The tiny bubbles are swim bladders. By pulling in or releasing air from these bladders they can position themselves up or down in the water at will, hiding down in the murk from those that would eat them at night, rising up during the day to hunt their own prey.
What do these guys look like when they pass from the larval stage into adulthood? We've all probably smooshed more than one. Adult Chaoborus have the same hunkered over predatory look of their close blood-sucking cousin, the Mosquito. Next time, wait just moment before going into smoosh mode. Adult Chaoborus can't bite - they've left their prehensile antennae and jaws behind, and their new mouths just aren't big enough to do any harm.
I couldn't find a good open source image of an adult Chaoborus, especially one that shows its similarity to a mosquito. Maybe one of the Bucketeers has one?
###
Sources:
www.metafysica.nl/nature/nomos_7.html
people.cst.cmich.edu/mcnau1as/zooplankton%20web/Chaoborus/Chaoborus.htm
www4.uwm.edu/fieldstation/naturalhistory/bugoftheweek/phantom-midge.cfm
crawford.tardigrade.net/bugs/BugofMonth05.html
###
Seattle. March 30. Chaoborus larvae are present in the Wetland pond.
###
Your turn. Any insights you might have regarding the stuff in the Wetland Pond will be welcome, but there's no need to stick to this topic. Everyone is welcome to report on anything they're seeing in their own natural neighborhood.
I have a hard time finding words before noon PDT, but promise to be here after that.
###
"Green Diary Rescue" is posted every Saturday at 1:00 pm Pacific Time on the Daily Kos front page. Green Diary Rescue has been good to Backyard Science, so take a minute to recommend, comment, and then link to your other off-Kos groups.