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Ulva taeniata
Sea Spiral, Ruffled Sea Lettuce
29 May 2025
Florencia Bay Beach, Vancouver Island, B.C., Canada.
Tide: 0.0 foot low at 9:22am PDT (measured at Tofino Tidal Station)
Weather: Mostly clear, wind WNW 5–10 km/hour, sea rippled, low westerly swell, humidity 82%, 12 ˚C.
Moon: Waxing Crescent (9.2%, 3 days); Next phase, First Quarter, 2 June 2025 at 8:40pm PDT; Previous phase, New Moon, 26 May 2025 at 8:02pm PDT.
Figure 1: Here we see Ulva taeniata in its habitat – growing anchored to rocks at sandy beaches with at the very low tide region. It also loves to grow in tideways – channels in which the tide runs regularly. Florencia Bay, Vancouver Island, B.C. Canada. May 29, 2025. Photo ID 27809 ©Seaweedwhisperings.com
Person 1:
Somewhat like Ulva stenophylla but much neater, tidier.
Has “places to go, things to do” and keeps doing it until the job is done. Does it with flair and intention, but not hurried.
Bright green and showy. Stands out even at a distance. Has things to show and express.
When the tide goes out Ulva taeniata gently settles on the substrate, still showing its beauty.
No hurry to get going again. When the time is right (tide comes back in), that will be soon enough to get back on task.
The long corkscrew appearance of this seaweed seems in perfect balance, a perfect design.
Can do pretty well in a group, but prefers to stand out alone where it can be the center of attention.
Figure 2: Laid out on the sand at a zero foot spring low tide, two Ulva species can be compared here. The upper left area shows individuals with slightly darker green blades that are broad and punctured irregularly with holes – this is Ulva fenestrata. The lower longer, thinner, highly ruffled bright green blades are Ulva taeniata. The spiral morphology and tendency to form long narrow divisions (like branching) is seen also. Florencia Bay, Vancouver Island, B.C. Canada. May 29, 2025. Photo ID 27810 ©Seaweedwhisperings.com
Person 2:
Long foliose thalli, that can branch, but even the branches grow long and lean.
And the pattern of the green is to have ruffles all along their length and these ruffles make the most interesting spiral-looking pattern – it is as if this is an algal version of a corkscrew!
Along with the shape, the color is notable – a bright lime green. I was going to say “fresh” green, but in fact it is not quite a deep enough green for that term; this green is bright – like it is lit up..., lit up with joy!
Grows anchored to rock where it can then stretch out over expanses of sand. Very little other macro algal life populates these sandy areas, and so Ulva taeniata has full exposure to light (no shading from other species) and it has full freedom to move.
And unimpeded movement is something it loves to do. The long thalli seem to want to go on and on, reaching out into their watery world. They don’t seem to find much use for growing past a maximum width, but growing in length, this they takes on with zeal.
Living adjacent to sandy areas also means they must be ok with being somewhat sand scoured, too. I observed the long strands moving in the stirred up water as it breaks in the shallows, and the green blades become temporarily engulfed in clouds of sand particles. This might seem like a hardship, but with this bright green seaweed it felt to me more like it was a stimulating circumstance – I imagined it as feeling like being lightly tickled in hundreds of thousands of places, and then very shortly after being washed cool again by the change of water action. What sensations!!
Joy, zeal, relishing in sensation..., this seaweed experiences life with their arms outstretched to take it all in.
Figure 3: The leading edge of the surf is stirring up some sand as it approaches these individuals. The lowermost blade is almost completely obscured in a cloud of sand particles. In this habitat and at this level of the intertidal zone this kind of circumstance is common; Ulva taeniata thrives here. Florencia Bay, Vancouver Island, B.C. Canada. May 29, 2025. Photo ID 27811 ©Seaweedwhisperings.com
Discussion:
The morphology of the thallus is not only attractive, it is functional. Particles of sand common in their habitat will not be held and carried by the blade, they will be easily shed off the spiral blades.
Not much bothers them; they are in balance.
Much seems to delight them, and what doesn’t is shaken off.
Lit up with joy..., the feeling came easily, and pondering the look a bit further there is almost a neon quality to their essence.
Arms are wide open to experience.
Openly transmits how they are. Both Persons received the energy of this seaweed with notable clarity and simplicity.
In other locations when we’ve seen this seaweed in its prime - the long bright green corkscrews laid out by a midsummer low tide, the effect is, “Wow, what a spectacular sight!”
When it is showing its perfect design, it is easy to be impressed by Ulva taeniata.
Figure 4: A closer view of a blade that has formed a “deep division”. These divisions, the high degree of ruffling all along the margins, and the overall spiral effect are details that are hard to precisely discern when this annual green alga is moving in water. Florencia Bay, Vancouver Island, B.C. Canada. May 29, 2025. Photo ID 27812 ©Seaweedwhisperings.com
Biology & Natural History Information:
Description:
Annual blades, arising from a discoid holdfast, are mostly bright grass-green in color and simple or with several long narrow divisions. Long and narrow, this species is 3 – 4 cm broad and 20 to 150 cm tall. Blades lack a stipe and also lack any median strip, are densely ruffled, and commonly spirally twisted. Like other members of the genus it is only two cells thick and the membrane is thinner at the margins (where the ruffles are formed), only 30 – 45 µm thick, and at the middle sections it is thicker 75 – 140 µm thick.
Habitat:
On rock (epilithic) adjacent to sand, in small tideways in the lowermost intertidal to upper subtidal (Hughey & al. 2024).
North Pacific Distribution:
The genus Ulva is possibly the most cosmopolitan of all seaweeds (Druehl L.D. & Clarkston B.E.) being found on all of the world’s coasts. U. taeniata, as is currently understood, is distributed in warmer waters than many of the Ulva species in the North Pacific. Its range extends from British Columbia, south through the coasts of Washington, Oregon, California, and on through to the Gulf of California and Mexico.
Remarks:
The type locality is Monterey, CA, U.S.A. (Silva & al, 1996).
Classification:
Empire: Eukaryota
Kingdom: Plantae
Subkingdom: Viridiplantae
Infrakingdom: Chlorophyta infrakingdom
Phylum: Chlorophyta
Subphylum: Chlorophytina
Class: Ulvophyceae
Order: Ulvales
Family: Ulvaceae
Genus: Ulva
Species: Ulva taeniata (Setchell) Setchell & N.L.Gardner 1920
Former name(s):
Basionym: Ulva fasciata f. taeniata Setchell 1901; Heterotypic synonym: Ulva dactylifera Setchell & N.L.Gardner 1920.
Figure 5: Afloat and stretched out as the tide pulls back out to sea, the balanced growth of the spiral ruffles allows a certain kind of lift – the blades seem to joyfully dance in the light near the water’s surface. They also seem like they need to keep to a narrow beam but they love to grow longer and longer. Florencia Bay, Vancouver Island, B.C. Canada. May 29, 2025. Photo ID 27813 ©Seaweedwhisperings.com
