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.
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June 15-18, 2022
San Juan islands, Pacific Northwest
During the daylight hours of last week, the waters of the Salish Sea had the lowest tides in a decade. A full moon (this month June 15) around the summer solstice always has the lowest tides of the year, and this year “the wobble in the moon’s orbit is nearing its peak, making the tides roll in and out more powerfully than usual. That wobble, known as the lunar nodal cycle, is giving us the lowest tides in 13 years.” per Ian Miller of the University of Washington. More than four vertical feet below the average low water mark, an extreme minus tide.
The daily email I get from iNaturalist for those days reported a nice selection of animals that observers saw along local uncovered shorelines, animals that are rarely exposed to the air. A real treat to see any of these! Except on occasions like this you’d have to be swimming underwater to see them. And the waters of the Salish Sea are COLD: 48°F (9°C)
Echinoderms as a group are highly vulnerable to exposure in air. Only a few can handle intertidal life, and even then they prefer shady spots while uncovered by the tide.
The Morning Sunstar (in the title image) is a major predator of other seastars, including the following three:
Believe it or not, sea cucumbers are also echinoderms. Their 5-part symmetry can be seen in the five rows of tube feet running down their body, unlike under the arms of seastars.
Arthropods are much better adapted to air exposure than most invertebrates since they have a hard waterproof covering. Even so, some prefer to live subtidally.
Mollusks: vary tremendously in form. The “shellfish” among them (clams, snails etc) are pretty well protected from drying out at a low tide, but others who have no waterproof protection, like nudibranchs and cephalopods, are more vulnerable.
Three nudibranchs, found in tidepools:
And two chitons. Chitons have shells but those don’t seal them off from the air.
And a cool fish:
While spring and early summer in the Pacific Northwest have been unusually cool and rainy this year, that weather was a gift to all these animals exposed by the extreme low tides last week. In contrast, you may remember the devastating dieoff of intertidal invertebrates last year at this same time in June when a heat dome settled over this area bringing record-breaking temperatures (More than a billion seashore animals may have cooked to death in B.C. heat wave, says UBC researcher). This year, seashore creatures got lucky.
Mostly sunny in the PNW islands today. Temperatures climbing into the 60s. It’s starting to feel like summer has begun.
WHAT’S UP IN NATURE IN YOUR AREA TODAY?