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 world around you. Snails, fish, insects, weather, meteorites, climate, birds and/or flowers. All are worthy additions to the bucket. Please let us know what is going on around you in a comment. Include, as close as is comfortable for you, where you are located.
As always, the Daily Bucket is an "open thread", with the intro photo diary some of what the diarist is seeing, in this case, me. Comments are wide open for observations..."from California to the New York Island, from the redwood forest, to the gulf stream waters.....sparkling sands...diamond deserts..."
April 5, 2013
Fisherman Bay, Salish Sea
Water was still as glass this day. While Mr O was in the marina store picking up brake cylinder stuff, I wandered down to the marina dock to see what the wildlife was up to. With no ripples on the surface, and good visibility still (since the plankton has not yet bloomed in earnest), it was pretty easy to see down into the water. It was much busier and more crowded below the surface than it is anywhere on land here.
To get these pictures, I was kneeling or lying flat on the floating dock surface. It is linked to fixed pilings, but the docks themselves float up and down with the tide, typically an 8 foot difference from the higher high tide and the lower low tide. It can be as much as a 12 feet, at a spring tide near a solstice. "Spring tide", btw, has nothing to do with the season spring. When the sun, moon and the earth are all lined up astronomically, the combined gravitational pull of the sun and moon creates really high tides and also really low tides. This happens near the full moon and the new moon. But since creatures on the dock are never out of the water, there's a lush subtidal community, untroubled by drying out for hours, extremes of temperature or attack by terrestrial predators. In a protected bay like this, there are no crashing waves either. There are other environmental stresses, but...that would be an interesting future discussion.
The white beauties above, each a foot or two long, are the Giant Plumose Anemone, Metridium giganteum. Relatives of jellyfish, those frilly tentacles have stinging cells that paralyze anything passing by. But unlike jellyfish, anemones are attached. Not permanently, but they don't move much. The fact that there are so many here says there's plenty of drifting food - zooplankton, fish, squid, seaweed. Below, we have a different species of anemone:
This Christmas Anemone, Urticina crassicornis
(though I learned it as Tealia crassicornis
) is common on the dock, though it lives in intertidal zones also, very low down, where it's immersed most of the time. Without the support of water, it hangs down, looking distressingly stretched out (gravity is not its friend).
Keep in mind, we are looking straight down into the water, so the anemone isn't really "upright", as it appears in this photo.
Rather, it is "sideways", but it makes no difference to the anemone, so long as it's supported by water. It lives in a three dimensional world, unlike us. Almost certainly, your brain is better able to perceive the array of creatures in this scene when their "ground", ie. the surface they are attached to, is down, and their "sky" is up. See the Blue Mussel, with it's two shells slightly apart? Actively feeding. We also have several species of red and green algae which do care where they are fastened: optimally, up near the surface of the water. As photosynthesizers, the algaes prefer shallower water where the light is brightest.
I saw several Decorator Crabs (Oregonia gracilis) clinging to the pilings themselves. There are two of them here, decorated with furry hydroids, bulbs of tunicates and shreds of sponges, scavenging detritus trapped between the pilings.
Notice how bare the piling surface is, with just a few barnacles. Partly that's because the brackets holding the docks to the pilings scrape it, going up and down with the tide, but mostly it's due to the low tide leaving it dry for hours. Unlike the sessile (attached) creatures, the crabs can go where they want, grazing on sponges, algae, shellfish, detritus, and will follow the water when it goes down.
Who else do we see in the community above, besides the two kinds of anemones? Let's dive below the orange tentacles.
Colorful aren't they? There are several palm-tree-like Feather Duster Worms (Eudistylia vancouveri ) either feeding with their purple tentacles spread, or withdrawn, showing the orange lining of their tube. That bright orange-yellow mass is a colonial tunicate, another filter feeder. There are about 50 other creatures in this little view, most of them animals.
Our rich cold waters are a lot more colorful than many people realize. One reason it's a bit of a secret is because very few people actually get in to see it. Understandable, as the water temperature ranges from 6-12 degrees C (mostly in the 40s, degrees F). Unprotected by a drysuit or a 7mm wetsuit, hypothermia will set in quickly, and you can die in an hour. I used to dive in these waters. I loved the riotous jungly kelp forests with huge colorful nudibranchs, clever octopus, wolf eels, cryptic rockfish, wildlife galore. But there came a time when the cold-water gear was too heavy and cumbersome to manage: besides the basic air tank, breathing apparatus, drysuit, instruments, I had to wear 30 pounds of lead to counteract the buoyancy of insulation. My cold-water diving days are in the past. But I can still lie on the dock looking down! You might be able to see a reflection of my camera in this photo:
Several of the Feather Duster Worm tubes here are covered entirely with sponges: red and yellow, along with some frilly hydroids.
The dockside community changes as I go further out into the bay. Close to shore, the invertebrates dominate. Further out, the algae takes over. Intermediate, we have both fighting for the valuable real estate. Pink and yellow tunicates in the lower right and upper left are holding on. It's possible the toxins in their tissue, a defense against grazing predators, may help deter the seaweeds.
On the outside of the dock, it's almost all algae. Why? Is it being out in the open, where water flows by unimpeded? Another factor I didn't think about until I started writing this diary was that there's more transient boat traffic on the outside, while the inner sections are long-term tie-up. Do boats scrape off attached creatures more out there, and then the algae grows back fastest? These fronds are less than a year old, while the anemones, tube worms, crabs, mussels, sponges, tunicates, urchins are all older, with 2-20 year life spans. The owner of this marina likes the dockside communities himself, and has allowed them to grow freely for the past 30 years as they will, unlike many dock owners who deliberately scrape off the "clutter". It makes this an oasis in the bay, since the bottom is mud, a much less suitable environment than a hard surface.
Here are two Plumose anemones at the extreme ends of their color range, which come in all shades between brown and white, though the white is most common. Did they move to this outer dock site after it was cleared of algae by a big boat, from an inside dock, or from lower down?
I've been observing the changes for here for many years. With this new hypothesis, I'll start looking at high traffic areas on the inner docksides, like the headwall in the picture below where the Blue Penguin is tied up temporarily after being put into the water after a refurbishing.
Looking out at these docks, you'd never know what a rich and busy world it is, below the waterline.
That's my backyard for today. What's happening in yours? Seen anything new for the season? Wet or dry for you? All observations are welcome in the Bucket!