February 24, 2018
Salish Sea, Pacific Northwest
I haven’t been walking very far lately so my go-to easy-walking beach — the bay I reported from last time — is where we’re visiting for today’s Bucket too.
The Daily Bucket is a nature refuge.
We amicably discuss animals, weather, climate, soil, plants, waters and note life’s patterns.
We invite you to note what you are seeing around you in your own part of the world, and to share your observations in the comments below.
|
The tide was even lower this time even though I was out there at the same time of day.
Short explanation: Tides are about an hour later each day. That has to do with the revolution of the moon around the earth, the moon’s gravitation being the primary driver of tides. Roughly speaking, it takes the moon 28 days to revolve around the earth, so each day it’s 1/28 further around. The day has 24 hours, so as the tide highs/lows advance in step with the moon overhead, they are an hour later each day. There a few other variables complicating this basic pattern, but that’s the basics.
Looking at the portion of the tide calendar above, you can see that a week ago the low tides were at night, while this week they were during the day. And that on Thursday the 22nd at 4 pm the tide was 1.5’, starting to come in, while on the 24th at 4pm the low tide was 0.5’ and just approaching lower low tide. Additionally, as we approach full moon (when the sun lines up with the moon increasing gravitational pull) the low tide gets lower. So, more beach this time.
With more of the beach uncovered, more of the Ornate Tubeworm bed was exposed. I watched a gull munching on something in the middle of the bed and discovered using my zoom lens it was NOT a tubeworm but a crab. Big surprise ;-)
There are legions of crabs of all sorts in this bay. One of the prettiest crab carapaces is that of the Helmet crab, Telmessus cheiragonus. Helmet crabs live in shallow subtidal eelgrass bottoms, eating eelgrass and other stuff there. They can bury themselves in the muddy sand for protection, but they do have predators, including sculpins (a slow moving bottom fish) and gulls. Gulls can dive a couple of feet into the water, so low tides leave these and other crabs easy prey.
Other signs of critters on the beach, dead and alive…..
Also in the frame above, shell fragments, a crab claw, and the tracks of some snail.
One of the holes in the beach belongs to a free-living polychaete, a relative of the tubeworms we met last time. I encountered Nereis vexillosa (or possibly N. virens, a similar looking worm that has the same common names and lifestyle) partially emerged from its burrow, a hazardous state at low tide with all these gulls marching up and down the beach. Variously known as a Pile worm (not to be confused with the tube dwelling Piling worm), Ragworm or Mussel worm (based on its common association with mussel beds), this pretty iridescent worm is mostly an algae eater, but like all its kind, can protect itself with its business end, as I can attest.
It squirms violently and everts its proboscis and jaws when captured, and may bite. (eol.org/...)
On this occasion I gently nudged it with my walking stick and it retreated back into its burrow.
And my last critter for today, a single shorebird quite a bit less common than the usual kinds here (Oystercatchers, Killdeer, Turnstones). I think it’s a Sanderling, but might be a Western Sandpiper. Both are pale in winter but Sanderlings are more gray.
Video of this shorebird finding something to eat.
The lower low tides are moving into nighttime hours, so there won’t be as much to see on the beach for another week.
~
Bucket’s open for your nature observations.
"SPOTLIGHT ON GREEN NEWS & VIEWS" IS POSTED EVERY SATURDAY AT 5:00 PM PACIFIC TIME AND WEDNESDAY AT 3:30 ON THE DAILY KOS FRONT PAGE. IT'S A GREAT WAY TO CATCH UP ON DIARIES YOU MIGHT HAVE MISSED. BE SURE TO RECOMMEND AND COMMENT IN THE DIARY. |