Corallina chilensis

Wedge-tipped Coral Seaweed

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: This boulder has only about one meter of its mass visible above the shifting sands of Florencia Bay yet it is the ideal habitat for certain seaweeds. On its surf facing slope there is a vibrant grouping of Corallina chilensis - the pinkish thalli and pinnate branching pattern are impressive. The lee side of this boulder is populated by Ahnfeltiopsis linearis and a bit of Ulva sp. too. Florencia Bay, Vancouver Island, B.C., Canada. May 29, 2025. Photo ID 27819 ©Seaweedwhisperings.com

Person 1:

Living in turbulence, in groups on isolated islands... sand-scoured boulders at Florencia Bay. The water action swirls the sand over and around Corallina chilensis, often forming deep pools below where this alga thrives.

Likes to live where it can dominate. In its isolation out in the open, it has an expansive view... everything is great! With unlimited possibilities!

My thinking is a bit clouded by too many ideas all at once. Trying to remember these to write them down. Needed to leave our prep discussion to settle down in quiet. My thoughts were fleeting, with no staying power, no patience, little retention.

Emerging with force and vigor from its crust.

Growth pattern appears very orderly, more or less aligned in the same direction when mature. Likes to be neat and smartly dressed.

I’m using the present tense more than usual.

Feel excitement while writing these notes. Don’t know why, don’t care. I had been thinking about C. chilensis for several days and was eager to get into this Whispering.

The bright whitish tips to the thallus are rather beautifully striking, capturing ones attention. Thus, easy to overlook the structural details beneath.

Figure 2: A close view shows many branch tips of this strikingly beautiful looking articulated coralline alga. White tipped lovely pinkish-gray coloration adds even more attraction to the strongly pinnate branching pattern. It looks delicate but it is tough – calcified tissues make every part of this seaweed strong like a stone, except for the tiny joints between segments. The joints add the bonus of flexibility which is very useful in wave swept locations such as the one visited this day. Florencia Bay, Vancouver Island, B.C., Canada. May 29, 2025. Photo ID 27820 ©Seaweedwhisperings.com

Person 2:

This zero foot low tide morning found us exploring the beach at Florencia Bay. Here there are vast expanses of sand that are dotted with occasional boulders and are rimmed in the distance by rocky headlands at the outermost edges. Growing from the sand-embedded boulders there was an interesting collection of marine macro algae – one suited to this particular set of habitat features.

Here we found Corallina chilensis carpeting some rocks with its lovely feathery pattered fans of pale pink. It was keeping company with other sand-tolerant seaweeds – often Ahnfeltiopsis linearis or Fredericqia decewii, and where Corallina chilensis was positioned was on the edge of the rock that faces the incoming ocean swells. This is a pretty looking alga but it is also very tough!

Corallina chilensis is an articulated coralline alga that grows from a crustose base. Therefore its anchor place is a solid layer of algal material that hugs whatever rock surface it has found to grow on. And it seems to do well where other species cannot. So, on this day, at a very low tide, we were seeing Corallina chilensis just exposed. Most days it would be underwater. This would be a saving grace, as at that point, sand abrasion would be less of a factor and while the constant flow of surf would be delivering fresh sea water full of nutrients.

However, that is not to forget the tidal conditions that it must endure when things are not so easy – and it is this that seems include the defining traits of this seaweed. Tenacious, firmly anchored yet just flexible enough, plucky, spirited and brave, and also graced with some beautiful branching patterns to keep things balanced, directed and also attractive.

The pattern of growth is really very lovely to look at, especially at the tips where it is newest. There is a strong pinnate pattern, like the fronds of a feather, especially if you think of the tip of a feather. It also is somewhat reminiscent of an arrowhead. There is a pointedness to this shape, and there is an agreement on the direction it’s moving in.

The newest growth on this alga is white and so this trims the pink branches in another attractive pattern. When it is newly budding out from its crust, there is a lot of white..., and the form that will be distinctive when it is more mature is only hinted at.

Some of the sand embedded boulders here were quite isolated. When populated with Corallina chilensis and one or two other seaweeds and observed as a whole, it looked like some kind of island forested with pink and orange or red trees! Living the island life..., that is something that involves certain aspects. You do have a certain isolation that allows you to do your own thing without interference. But you also must be self-reliant. You must be good with your own company and that of your close neighbors. And to establish new colonies, you must really set out into unknown territory in hopes of success.

I think these features shape the kind of energy I could feel from this little coralline alga. It was strong. Here to stay. Fine as it is where it is. Set to meet whatever comes its way. Tolerant of one or two neighbors but not really interested in interacting with them much. Grows with its own sand shielding armor – a calcified coating that resists degradation, but also has flexible joints so it can enjoy the surf and rebound as it chooses.

Figure 3: Growing from a rock that is totally buried in sand, here we see Corallina chilensis joined by two forked-seaweeds – Fredericqia decewii and Ahnfeltia fastigiata, and from the animal kingdom there are several retracted anemone (looking like greenish and pink gelatinous textured donuts – scientific name is Anthopleura elegantissima). Florencia Bay, Vancouver Island, B.C., Canada. May 29, 2025. Photo ID 27821 ©Seaweedwhisperings.com

Figure 4: Caught while photographing chitons, this view of the crustose base with newly budding foliose thalli shows the very young form of Corallina chilensis. Some of the new growth is already showing the opposite branching pinnate pattern. Florencia Bay, Vancouver Island, B.C., Canada. May 29, 2025. Photo ID 27822 ©Seaweedwhisperings.com

Discussion:

Living in turbulence – we thought about this further and found that Corallina chilensis relishes the excitement of the turbulence. Many persons don’t find the idea of facing turbulence to be a welcome one due to believing it involves turmoil or conflict or upheaval. This seaweed has yet to categorize turbulence as anything unpleasant and still finds excitement and joy in it; it hasn’t yet seen the downside that can come with turbulence.

Where it likes to live it is out in the open and has an expansive view; we found that for this seaweed the attitude connected to that expansive view is that “everything is great” and there was also a sense of “unlimited possibilities!” There’s a “bring it on” kind of willingness in this seaweed’s energy. It’s ready and willing and keen to jump in. As yet, they have experienced little to diminish or jade their eager disposition.

They have a lot of energy for the ‘getting started’ phase of things, but usually not so much for the keeping it going or bringing to fruition aspect. We understood that in the simple comment “emerges with force and vigor”; here “emerges with” is the key term.

Emerging with force can lead to them being able to ‘dominate’, however where they are dominating the landscape it is usually some place where the living conditions are tough. They endure and persist in areas where other ‘wiser and more experienced’ seaweeds wouldn’t bother to try. Their dominance can also be a result of the fact that they’re not very neighborly; they are not so keen on accommodating and sharing – those kinds of things are not really on their radar.

Both with their physical location and its challenges, and with interactions with others, it feels like Corallina chilensis can “take a lot of abuse” and that it just “washes over” them. They can have the ability to not take things personally, and when interacting with others they can sometimes not be personable enough.

It was interesting to see how Person 1 caught one aspect of this seaweed’s mental state; he felt that his thinking was clouded and that if he wanted to do best with his thoughts he needed to be on his own, someplace quiet (isolated) and that making notes was needed for even the most basic retention. His thoughts were fleeting and had little staying power. We pondered this a bit and found that this links with the ‘turbulence’ theme; when there is much coming at them it is better to forget the last event and clear one’s mind to be ready for the incoming one. If they can’t ‘forget’ or allow their thoughts to exist only fleetingly, then their thinking can become cluttered. In this energy their preference and their strength is the capacity to engage in the current moment. When everything else, past or future has no staying power in their thoughts, they really are able to be present at their best capacity.

The growth pattern / morphology of this seaweed is orderly – there is a dichotomous balance, especially at the leading tips. Does this growth that is more or less equal on each side give them a natural balance so that they don’t sway off course from their direction they’re intended to head? We thought that this was a definite yes. The look was almost “neat and smartly dressed” and it feels that this is their natural ‘normal’ and it is not something they have to work at. As it can be with very good looking humans, perhaps it is the result of some pretty strong luck from the gene pool. The bright whitish tips capture attention with another type of added beauty; again we felt this is something not ‘deliberate’ or ‘learned’ but much more a simple expression of their inherent nature.

This red alga loves to meet the surf head on. They find fun in that! And to add to the fact that they are sand burial and sand scouring tolerant, their habit choice has this third stress of direct exposure to wave action (at certain tide levels). This is something they’ve learned to handle in a mode that is distinctive to their clade. Their cells are literally reinforced with calcium carbonate and this gives their tissue a true toughness; and to deal with the surf..., well, they’ve added in articulating joints that are non-calcified and therefore flexible. So they have both – a toughness and inflexibility in the calcified portions of their being and an ability to react with flexibility if stresses require them to ‘bend’ a bit.

The toughness / calcification is reflected in their nature of being unbothered by the little things, not taking things personally, having a ‘bring it on’ attitude. The need for flexibility, though, is their point of vulnerability, and if that is what is stressed or damaged or attacked, they have few defenses. They can then fall apart or be seriously broken. If they survive such a situation this is one thing we felt they would ‘retain’; such strong trauma could prejudice them against repeating those damaging experiences.

With the pattern of dichotomous branching especially at the tips of the thalli there is a pointedness, a pinnate pattern or and overall arrowhead shape. All of these things suggest that there is an agreement on and a certain direction they’re going in. And they do seem to be in motion, want to be going onward, just as looking at an arrow suggests movement and looking at a circle suggests being centered in place. We felt also that in this seaweed the chosen direction is not well thought out; it is intuitively chosen AND it is enthusiastically pursued.

Thinking a bit more on the isolated habitat, and their self-reliant nature, we found that, as a whole, their energy is often notably spirited and surprisingly brave. We liked the word “plucky” for them! This seaweed also has a noteworthy crustose base that is well-adhered to rock. Having a strong connection to its own base gives Corallina chilensis the freedom to play with the surf, and to meet what comes its way without fear.

The crustose base of this seaweed is more than an anchor, it is also an area of “potential waiting to happen”. This seaweed feels as if it cannot thrive without a strong base to fall back on if things get really bad. Without that strong base they cease to exist; with it they have a cushion. It is the source of their inner energy. It’s the foundation of what they need to be a photosynthetic organism – transforming light to fuel and algal form.

Figure 5: The inset shows the long axes of the numerous thalli of C. chilensis which support the dichotomously pinnate branching at their tips. The older sections of the main axes stand out like a string of pink or white stone beads. Each ‘bead’ is separated by a genicula (joint) that is non-calcified and this permits flexibility of the thallus. Some of the deeper pink crustose base is visible and the pinnate or arrowhead pattern of the branch apexes stands out, too. Florencia Bay, Vancouver Island, B.C., Canada. May 29, 2025. Photo ID 27823 ©Seaweedwhisperings.com

Biology & Natural History:

Description:

Erect shoots, 5 – 15 cm tall, are calcareous and arise from a crustose base of indefinite extent. An articulated coralline alga, this seaweed has a structure composed of calcified intergenicula alternating with non-calcified genicula. The genicula serve as points of flexion in what would otherwise be a stiff and almost stony thallus. In C. chilensis the lower intergenicula of the axis are sub cylindrical and up to 1 mm broad; the upper intergenicula are compressed, cuneate (wedge shaped), and up to 1.25 mm broad. This difference in shape of the intergenicula is clearly visible and notable in the field. Branching of the axis is dichotomously pinnate, with progressively shorter branches occurring toward the apex of the axis – this gives the alga a feathery appearance. Branches tend to lie in one plane and the diameter of the branches, as compared to the axis is robust - nearly similar in diameter. Most of the branches are pinnately branched, with those toward the base of the axes frequently bi-pinnate.

Habitat:

On semi protected to exposed rocks from the low intertidal to shallow subtidal zones, and also in drainage channels or deep pools higher in the intertidal zone.

Distribution:

Cosmopolitan in range, this species has been identified from many countries and oceans of the world.

North America: Alaska, British Columbia, Washington, Oregon, California, Gulf of California, Mexico. South America: Chile, Peru, Argentina, Ecuador. Africa: South Africa. Antarctic and Sub-Antarctic Islands. Australia and New Zealand: Lorde Howe Island, Norfolk Island. Pacific Islands/Pacific Ocean: Galápagos Islands.

Remarks:

In his publication “Nereis Australis or Algae of the Southern Ocean”, William Henry Harvey marveled at the property of the coralline red algae to: “withdraw carbonate of lime from the waters of the sea and laying it up as a strengthening to their walls”. This calcification of the ‘plant’ renders it closer to stone in texture compared to the more typical soft and flexible “vegetable structure” of other algae. He writes that “this family of algae were once confounded with poypiferous zoophytes” and it was only in his time (publication of Nereis Australis was 1849) that “the labours of several distinguished modern observers” had established with no need for further proof that the Corallineae have “a vegetable nature”. Having studied specimens from the southern oceanic regions largely by use of “solitary specimens brought home by voyagers and preserved in herbaria” he stated: “No tribe of Algae has been more neglected than the Corallineae, or requires a more patient and attentive study from persons having access to living plants”. Written at a time when scientists expressed wonder in their written publications he also stated the opinion that: “very few exceed this family in the beauty and grace of its members. A rich harvest of novelty awaits the explorer in tropical and subtropical waters.”

The genus Corallina is present in these southern waters Harvey is referring to but also extends to high latitudes in both hemispheres, and the species are most numerous in the northern one. Corallina chilensis, with its type specimen (collected by C. Darwin) at Valparaiso, Chile, has a wide distribution in southern and northern waters.

Reinstatement in 2023 of Corallina chilensis (family Corallinaceae, phylum Rhodophyta) from Corallina officinalis var. chilensis (Decaisne), determined by a whole new set of “distinguished modern observers”, Schipper, S.R., Shivak, J.P., Hind, K.R., Miller, K.A., Hughey, J.R., Gabrielsen, P.W., & Martone, P.T., was based on DNA sequencing of the type material collected by Darwin.

Classification:

Empire: Eukaryota

Kingdom: Plantae

Subkingdom: Biliphyta

Infrakingdom: Rhodaria

Phylum: Rhodophyta

Subphylum: Eurhodophytina

Class: Florideophyceae

Subclass: Corallinophycidae

Order: Corallinales

Family: Corallinaceae

Subfamily: Corallinoideae

Tribe: Corallineae

Genus: Corallina

Species: Corallina chilensis Decaisne 1849

Former name(s):

Corallina officinalis var. chilensis (Decaisne) Kützing 1858

Figure 6: Yet another ‘island’ in this ‘sea of sand’ – the above pictured boulder has a strong population of Fredericqia decewii – the wiry forked dark red seaweed at the lower levels, then a strong showing of the pink colored Corallina chilensis, and finally topped off with a showing of ruffled bright green Ulva fenestrata blades. Florencia Bay, Vancouver Island, B.C., Canada. May 29, 2025. Photo ID 27824 ©Seaweedwhisperings.com