Tag: marine invertebrates

Collateral damage

Posted on by Allison J. Gong

My home town of Santa Cruz made national news the other day, 23 December 2024, when a series of massive swells caused part of the Municipal Wharf to collapse into the ocean. People in the restaurants and other businesses had to evacuate immediately, and three people were dropped into the water of Monterey Bay (they were all rescued safely and no human lives were lost). The bathroom building fell into the water and washed up on the beach at the mouth of the San Lorenzo River. Almost immediately, memes appeared, advertising a 2-bathroom unit with both river and ocean views, renting for $6000/month. Given the exorbitant rents here, you could argue that maybe this is a pretty good deal.

That afternoon, the same swell tore through the Santa Cruz Small Craft Harbor and replicated the damage done by the Fukushima tsunami in March 2011. The damaged docks had been replaced in 2014, but this recent damage ripped them up again. Boats and docks were thrown around and crashed into each other. An unknown amount of diesel fuel and gasoline were also “liberated” into the water.

My friend Murray has a little boat, Scherzo, that lives in the upper harbor on G dock. On the day of the worst swell, Murray had gone down to see how Scherzo was faring. At that point she had taken at least some cosmetic damage to her paint but didn’t seem to be taking on any water except rain water. The harbor patrol had closed all of the docks so he couldn’t get close enough to see if there were worse injuries. At one point another boat had come down the channel and gotten wedged under Scherzo so she was floating on top of it. Somebody rescued Scherzo and tied her up at a spot just under the ramp from her usual berth. Yesterday, Christmas Day, Murray called us to say that he was down at the boat and asked if Alex (my husband) could help him get her out of the water, as more big swells were forecast. I’m not very useful when it comes to boats, but I went along to watch things from above and hold lines and such.

Before they could take Scherzo out of the water, they had to make sure she was seaworthy enough to be driven down to the boat ramp at the lower harbor.

Dock with two large boats tied up on one side and one small boat tied up on the other side. One person in the small boat. One person crouching on the dock next to the small boat
Murray and Alex give Scherzo a check-up
2024-12-25
© Allison J. Gong

Behind Murray, who is wearing the pink cap, you can see damage to the finger dock. And notice that the big boats aren’t sitting straight in their slips. Scherzo‘s usual spot is on the other side of the ramp; she got pushed under the ramp and a kind soul tied her up here.

This is the capsized boat that had gotten wedged under Scherzo. It was now stuck under the ramp, just in front of Scherzo‘s spot.

Capsized boat wedged under a pedestrian bridge
Capsized boat under ramp
2024-12-25
© Allison J. Gong

Scherzo‘s engine started right up, and the boat itself having been deemed safe to drive by Alex the Engineer, Murray took her down the harbor slowly. Alex and I met him at the boat ramp.

While we were waiting, we noticed that some of the pilings from the busted-up Wharf, which is more correctly a pier rather than a wharf, had been hauled out of the water and set in the parking lot.

Wharf pilings in the harbor parking lot
2024-12-25
© Allison J. Gong

Knowing that the biota on the pilings would be very similar to the critters I see in the rocky intertidal, I had to investigate. And it was very sad. Most of the animals had died waiting for a high tide that wouldn’t return. Some of the barnacles were still alive, albeit just barely so.

Log lying on pavement, covered with small pink blobs and large brown objects also covered with small pink blobs.
Large barnacles (Balanus nubilus) and pink corallimorpharians (Corynactis californica)
2024-12-25
© Allison J. Gong

Here’s a close-up shot of one of the big barnacles encrusted with other animals:

Beige pyramid-shaped structure with pink blobs on the lower surfaces
Large barnacle (Balanus nubilus) and pink corallimorpharians (Corynactis californica)
2024-12-25
© Allison J. Gong

There were many empty worm tubes, former homes of the beautiful Eudistylia polymorpha. I saw one dead worm that had fallen out of its tube:

De-tubed feather duster worm, Eudistylia polymorpha
2024-12-25
© Allison J. Gong

One of the rocky intertidal denizens, the pink barnacle Tetraclita rubescens, was there, too:

Pink barnacle (Tetraclita rubescens) with smaller barnacles (Balanus glandula) and mussel byssal threads
2024-12-25
© Allison J. Gong

To get a feel for how big Balanus nubilus and Tetraclita rubescens are, my left index fingernail measures exactly 10 mm across. That B. nubilus is a big sucker!

Large volcano-shaped structure with two smaller pink volcano-shaped structures on the side. Finger for size reference
Balanus nubilus and Tetraclita rubescens
2024-12-25
© Allison J. Gong

Balanus nubilus is a strictly subtidal species that I never see in the intertidal. Tetraclita rubescens occurs in both the intertidal and the subtidal; some of these subtidal specimens were larger than the ones I see in the intertidal. Most sessile marine invertebrates can feed only when they are covered by water, which means that the ones living in the intertidal don’t feed at low tide. Thus the subtidal T. rubescens can get larger than their intertidal conspecifics, simply because they can feed 24/7. We see the same pattern with mussels in the intertidal: those higher up in the mussels’ range are smaller than the ones in the lower part of the range.

Some of the barnacles were still alive. They can close up their shells and wait out a low tide. But sitting out of the water for longer than a day was more than even they could withstand.

Other old friends were there, including many sea anemones. This is the sunburst anemone, Anthopleura sola, looking the way it does when I see it in the intertidal at low tide.

Cylindrical animal hanging down from vertical surface
Sunburst anemone (Anthopleura sola)
2024-12-25
© Allison J. Gong

Other anemones had been caught in the act of dividing. These would be the cloning anemones, Anthopleura elegantissima.


2024-12-25
© Allison J. Gong

2024-12-25
© Allison J. Gong

Probably the saddest thing was a desiccated red octopus on the pavement. It had probably plopped out of a nook and tried to make its way back to water. Poor little thing.

Grayish-brown lump with suckered arms
Red octopus (Octopus rubescens)
2024-12-25
© Allison J. Gong

The organisms on these pilings were caught in their final moments of life, just as the citizens of Pompeii and Herculaneum were when Mt. Vesuvius erupted in 79 AD. Some of them had tried to escape (the octopus) and some were not quite dead yet (the barnacles), but the inevitable is well, inevitable. At some point the pilings will be removed to the landfill. The same thing happened when the harbor docks were replaced in 2014. I happened to be there with a class and we saw all of the old docks piled up in the parking lot, with all of the attached biota slowly drying up in the sun.

So while there will be reports in the coming days about how many millions of dollars it will take to rebuild the harbor (again) and the pier, let’s not forget that there were other losses that cannot be assigned a dollar value. There is also a potentially major ecological impact of new (again) harbor docks. When the old docks were removed in 2014, they had been covered with a decades-old fouling community. The new docks were pristine new habitat for recruits, and shortly after they were put in I noticed an invasive brown alga, Undaria pinnatifida, which I hadn’t seen before. Undaria is a western North Pacific edible seaweed that is known culinarily as wakame. In recent years it has become one of the most abundant macroalgae in the lower areas of the harbor. The docks that were destroyed this week had been in place for only 10 years or so, and it will be interesting to see how primary succession occurs when new docks are installed. Hmm, that sounds like something I can have my Ecology students document and monitor!

A celebration of worms

Posted on by Allison J. Gong

Yesterday, 30 June 2023, was deemed by the National Museum of Natural History to be International Polychaete Day, and the Smithsonian had an entire day of talks and activities for visitors to learn about the marine segmented worms. And you know me: I’m in favor of any event that draws attention to the animals that are not like us. So this is my own little celebration of worms I encountered over this past week.

Living with sea stars

I’ve written before about how many of the bat stars (Patiria miniata) I see at Pigeon Point carry small commensal polychaetes on their oral surface, often associated with the ambulacral groove. Several taxa of echinoderms are known to have associations with polychaetes, and I’ve seen worms crawling around on sea stars, sea urchins, and sea cucumbers. Oxydromus pugettensis is the polychaete I’ve seen on the bat stars in the field.

5-armed cream colored star-shaped animal being held in a human hand; two small brown worms on animal's surface
Commensal polychaete worms (Oxydromus pugettensis) on oral surface of bat star (Patiria miniata) at Pigeon Point
2018-06-01
© Allison J. Gong

Years ago now, I collected some bat stars to bring back to the lab. Some of them had worms, and I was interested in seeing how long the worms stuck around once the stars were in captivity. The answer was “Not very long.” I seem to remember that the stars had lost their worms within a week. And since then, despite having many bat stars come through my hands at the lab, none of them have acquired worms.

Until now. This past week I was moving stars around and cleaning tables after flushing seawater pipes. I have a large bat star and a smaller one running feral in one of the tables. I picked up the larger star and turned it over just to check on it, and saw a dark squiggly thing. It was a worm!

Hand holding a 5-pointed star shaped animal, mottled orange and brown in color
Aboral surface of bat star (Patiria miniata)
2023-06-26
© Allison J. Gong
Hand holding a 5-pointed star-shaped animal, cream in color
Oral surface of bat star (Patiria miniata)
2023-06-26
© Allison J. Gong

Can you see the dark squiggle on the oral surface?

Here’s a close-up of the worm:

Cream-colored scales surrounding groove containing flat-topped clear tubes. Small dark brown worm tucked into side of groove.
Oxydromus pugettensis in ambulacral groove of Patiria miniata
2023-06-26
© Allison J. Gong

This is the first time I have ever seen a sea star acquire a commensal worm. It’s gotta happen, because we see worms on stars in nature. But I do wonder about this relationship. The worms are highly mobile and probably leave one star and join another quite frequently, or remain free-living (i.e., not on a host star). I had brought in some algae the previous week, and it’s quite possible that the worm came along as bycatch and found its way to the bat star. I checked on the star later in the week, and did not see the worm. It hadn’t joined the smaller of the bat stars, either.

Baby worms

This past Monday I did a plankton tow off the end of the Santa Cruz Municipal Wharf. This was my first plankton tow of the year, and I wanted to see what was there. The water was very clear and the phytoplankton were lacking, but there was a decent diversity within the zooplankton. Of particular interest to this report were the baby worms.

Baby worms are present in any plankton tow collected at any time of the year, although they may be more abundant at some times compared to others. Clearly there isn’t much seasonality to reproduction in some of our local polychaetes. The most commonly seen baby worms in plankton samples are the metatrochophores of worms in the family Spionidae.

Adult spionids are benthic and live in tubes. They have two long palps that extend from the anterior end and are typically used to scrape up organic deposits from the area surrounding the tube. Like most polychaetes, spionids are broadcast spawners that cast gametes out into the water, where fertilization and development occur. Polychaetes go through a larval phase called a trochophore, defined by a ring of cilia (the prototroch) that produces the feeding current for the animal. Incidentally, many molluscs also go through a trochophore stage, but that’s a story for another time. Some polychaetes, including the spionids, have a second planktonic stage called a metatrochophore. The metatrochophore is a much larger and more elaborate version of the trochophore, with eyespots and few to many segments complete with associated bristles. They can crawl as well as swim. Some of them can be 3 mm long, which is pretty big for something that is still up in the plankton. The spionid metatrochophore also has the two long palps, which sometimes remind me of the flaps on Elmer Fudd’s hat.

These are photos of the same individual worm. It’s about 2 mm long, a little longer if all stretched out.

Tan colored, segmented object curled into a loose circle. One end is pointed and bears two ear-like flaps that extend backwards.
Metatrochophore of spionid polychaete
2023-06-26
© Allison J. Gong
Tan colored, segmented object, approximately bullet-shaped. One end is blunt, the other tapers to a rounded point. Tentacle-like structures extend along the sides of the body.
Metatrochophore of spionid polychaete
2023-06-26
© Allison J. Gong

There was another type of polychaete metatrochophore in the sample, but I don’t recognize which family this one comes from. I should, because I see it frequently enough to know it isn’t unusual. It might be a young phyllodocid metatrochophore, but that’s just a guess. Anyhow, this creature has fewer segments than the spionid metatrochophore and lacks the spionid’s long palps. It does have eyespots, segments with bristles, and (I think) two pairs of tentacles associated with the head region. This individual also contains a lot of oil droplets, visible as those small dark circles in the dorsal half of the body behind the head. Oil droplets serve as energy stores and flotation devices. Many marine invertebrate larvae stockpile calories as they feed and store them in oil. In some cases, these calories are needed to sustain a later larval stage that doesn’t feed.

Polychaete metatrochophore
2023-06-26
© Allison J. Gong

There you have it, my belated contribution to International Polychaete Day 2023. I always enjoy finding worms in our plankton. They have a lot of personality, and it’s fun to watch them zooming around. They are really fast swimmers, and I have to squash them under a coverslip—just a little—to get them to hold still long enough to take photos. Always worth the effort, though!

Exception to the rule

Posted on by Allison J. Gong

Ask any marine biology student to list some interesting factoids about barnacles, and one of them should be “Barnacles are benthic and sessile” by which they mean that barnacles live their entire lives glued to a single spot. This definitely describes what it means to be benthic. Barnacles are indeed stuck, for better or worse, to the location that their cyprid larva selected. Once the cyprid glues its head to the rock or other hard substrate, that’s it. A bad choice could mean that the barnacle starves, desiccates, or is unable to mate. A good choice means an opportunity to live long and prosper.

How is it, then, that we have things that are called pelagic barnacles? These are barnacles that live permanently attached to objects that move through the water. The objects can be living (e.g., whales or turtles) or non-living (e.g., boats). Pelagic barnacles are not just traveling versions of the species we see in the intertidal or on docks and pilings—they are different species altogether.

Yesterday morning I went to Younger Lagoon to see what had happened during the most recent storm. The lagoon had once again breached through to the ocean, and bits of Monterey Bay were sloshing into the lagoon. None of that was unexpected.

What did catch my eye were the fuzzy blotches on some of the pieces of wood that had washed up onto the beach.

Small log festooned with interesting objects
2023-03-10
© Allison J. Gong

A closer look confirmed my thought that these were pelagic barnacles in the genus Lepas. These are a type of gooseneck barnacle, similar in overall morphology to the very common intertidal Pollicpes polymerus.

Pelagic barnacles (Lepas sp.) on piece of wood
2023-03-10
© Allison J. Gong
Lepas sp. on piece of wood
2023-03-10
© Allison J. Gong

These barnacles were small, and having been emersed for at least several hours were definitely not looking their best. They didn’t smell dead just yet, but since they had zero chance of getting back into the water before the next high tide, were doomed. A few of them had their cirri—the modified thoracic appendages that barnacles sweep through the water when feeding—extended, which I’ve seen before with barnacles on their last leg. See what I did there? I did touch some of the cirri, and the barnacles did not respond at all, although they had not yet dried out to the point of crispiness.

Lepas makes a living attached to objects that float in the ocean. I usually see them on logs or smaller pieces of wood, as they are here, but do occasionally find tiny ones on the blades of giant kelp (Macrocystis pyrifera). Living attached to objects that float with the currents means the barnacles are constantly moving through the water, able to feed 24/7 without the constraints of high and low tide. Compared to the robust gooseneck and acorn barnacles of the rocky intertidal, Lepas is translucent and delicate, with plates that are only weakly calcified. Given its lifestyle, Lepas rarely has to withstand bashing surf or waves; by the time it does, its substrate is inevitably headed onto shore, where the barnacles will die anyway.

So there you have it—a barnacle that flouts the rule and manages to be both benthic and pelagic. Or perhaps I should say that it is benthic but has a pelagic lifestyle. Either way, Lepas is making the best of both worlds, isn’t it?

A most unusual sort of snail

Posted on by Allison J. Gong

One of the many delightful animals in the rocky intertidal is the vermetid snail, Thylacodes squamigerus. Unlike their more typical gastropod relations, the vermetids don’t live in a shell, per se. Instead, they live in a calcareous tube, which forms a loose coil draped over the surface of a rock. The tubes can be up to about 12 mm in diameter, and, if straightened out, about 15 cm long. In some locations, Thylacodes can be very abundant. In a recent visit to Point Pinos in Pacific Grove, I saw many of them in the low intertidal. I occasionally see them on the northern end of Monterey Bay and points farther north, but at nowhere near the abundance I see in Pacific Grove. At a larger scale, iNaturalist shows observations of T. squamigerus from northern British Columbia down to southern Mexico.

Three coiled white tubes and one spherical snail on a rock amid greenish seaweed
Trio of vermetid snails (Thylacodes squamigerus) with their more conventional cousin, the black turban snail (Tegula funebralis)
2022-06-03
© Allison J. Gong
Loosely coiled whitish tube on a rock
Thylacodes squamigerus
2022-06-03
© Allison J. Gong

Most snails are either grazers (e.g., abalones, limpets, turban snails) or predators (e.g., whelks, conchs, cone snails). Thylacodes is a bit of an outlier with regards to feeding as well as housing, for it is a suspension feeder. Being entirely sessile, it cannot go out and forage. And unlike its doppelganger, the tubeworms Serpula columbiana and S. vermicularis, Thylacodes does not create a water current to catch food on ciliated tentacles. Instead, it spins threads of sticky mucus that thrash around in the current and capture suspended detritus. When the tide is out the snail hunkers down in its tube, same as any worm. It cannot feed unless it is immersed. Where the worms live in the low intertidal on exposed rocky coasts, the water is moving constantly, and it requires relatively little energy for Thylacodes to feed the way it does. As a bonus, even the calories expended in producing the mucus are recouped, as the snail ingests the mucus strands as well as the food particles they capture.

When the tide came back, I got to watch Thylacodes in action. At Point Pinos there are some areas that form lovely tidepools, deep enough for animals to react to the return of the water and clear enough to make photography and videography possible. So standing knee-deep in a pool I stuck the camera underwater and hoped for the best. And I got lucky—you can see the mucus threads!

See here:

Thylacodes squamigerus
2022-06-03
© Allison J. Gong

and here:

Thylacodes squamigerus
2022-06-03
© Allison J. Gong

And not only that, but I captured some video footage. I use a point-and-shoot for these underwater shots, and usually don’t know what or whether I’ve shot anything good until I download images and video at home. Color me happy to have seen these clips!

Despite the unusual aspects of its biology, Thylacodes is indeed a snail. It has a conventional snail’s radula, and uses it the way, say, an owl limpet (Lottia gigantea) uses hers to scrape algae off rocks at Natural Bridges. Only instead of scraping the radula against rocks, Thylacodes uses its radula to reel in the detritus-laden mucus threads. That’s what’s going on in the second video clip above.

So there you have it, another of my favorite animals. Thylacodes is one of those animals that doesn’t look like much when you see it just sitting there. But we get to see it only during the tiny fraction of its life that it spends emersed. As with most inhabitants of the rocky intertidal, much of Thylacodes‘ life occurs out of sight for human eyes. This makes the occasional sighting of Thylacodes under water especially enlightening. And delightful!

Natural Bridges

Posted on by Allison J. Gong

Last week we had some of the best low tides of the season, and I was grateful to spend three consecutive mornings in the intertidal. The picture-taking conditions were fantastic when I went to Natural Bridges, and I snapped away like a madwoman. Unfortunately, last week was also finals week, and it wasn’t until I got all of the grading done and actual grades submitted that I let myself look at the photos. And there were a lot of good ones!

There are many wonderful things about the early morning low tides. One of the best is that most people prefer to remain in bed rather than get up before the sun and splash around in cold water. The past several weeks had been very busy, with little time for solitude, and I badly needed some time by myself in nature.

Usually when I post an entry here I have a story to tell. This time I don’t, unless the photos themselves tell the story. Let me know what you think.

Rocks covered in green surfgrass and brown seaweed, surrounded by water. Wave breaking in the background. Clouds in the sky.
Low intertidal at Natural Bridges
2022-05-17
© Allison J. Gong

Act I

At this time of year the algae are the stars of the show. They are at their most lush and glorious for the next several weeks.

Brown and dark iridescent seaweeds on rocks
Assemblage of mid-intertidal organisms
2022-05-17
© Allison J. Gong

Even in the sand, the algae were abundant and conspicuous. In the low intertidal the most prominent algae are the kelps. Here the feather boa kelp (Egregia menziesii) and the various Laminaria species are doing really well. Egregia also occurs higher in the intertidal, but Laminaria and Macrocystis (just visible along the right edge) are low intertidal and subtidal species.

Kelps (Egregia menziesii, Laminaria setchellii, and Macrocystis pyrifera) in the low intertidal
2022-05-17
© Allison J. Gong

My absolute favorite sighting of the morning was this group of algae on top of the sand. I love the way that the algae are splayed out. They are just so pretty!

Assemblage of algae in the sand
2022-05-17
© Allison J. Gong

Macrocystis pyrifera is justifiably well known as the major canopy-forming kelp along our coast. But it does occur in the low intertidal, as mentioned above.

Long strands of golden-brown seaweed
Giant kelp (Macrocystis pyrifera)
2022-05-17
© Allison J. Gong

Intermission

Act II

And now to focus on some individual organisms. Starting with my favorites, the anemones. This time it was the giant green anemone, Anthopleura xanthogrammica, that was the star of the show.

Large bright green sea anemone
Green anemone (Anthopleura xanthogrammica)
2022-05-17
© Allison J. Gong

I experimented with close-up shots, too!

Close-up of green sea anemone tentacles
Close-up of green sea anemone tentacles
Green anemone (Anthopleura xanthogrammica)
2022-05-17
© Allison J. Gong

There was a clingfish (Gobiesox meandricus), in its usual under-rock habitat. Don’t worry, I made sure to carefully replace the rock as I found it. This fish was about 10cm long. It may be the first clingfish I’ve ever seen at Natural Bridges. Clearly, I need to do more rock flipping.

Mottled brown fish with large head, on a rock
Northern clingfish (Gobiesox meandricus)
2022-05-17
© Allison J. Gong

A clingfish’s pelvic fins are fused together and modified to form a suction cup on the ventral surface. Clingfish can hop around a bit and are super cute when they eat. They sort of dart forward and land on the food, then shuffle around as they ingest it.

The coralline algae were both abundant and flourishing. They are looking fantastic this season. Someday I’ll study up on the coralline algae and write about them. For now, here are some happy snaps of Bossiella.

Pink, stiff, seaweed. Body of repeated sections.
Bossiella sp.
Pink, stiff, seaweed. Body of repeated sections.
Bossiella sp.
Pink, stiff, seaweed. Body of repeated sections.
Bossiella sp., one of the erect coralline algae
2022-05-17
© Allison J. Gong

Such a beautiful organism!

Sticking with the pink theme, another oft-overlooked organism is the barnacle Tetraclita rubescens. It has a few common names, including pink volcano barnacle and thatched barnacle. It is the largest of the intertidal barnacles along the California coast, and can be fairly abundant in some places. It is never as abundant as the smaller white (Balanus glandula) and gray/brown (Chthamalus dalli/fissus) barnacles, though.

Large pink barnacles on a rock
Tetraclita rubescens, the large pink barnacle
2022-05-17
© Allison J. Gong

Which brings us to my favorite color, purple. The tentacles of the sandcastle worm, Phragmatopoma californica, are a beautiful shade of purple. You don’t get to see the tentacles unless the worm is under water, and with the tide as low as it was when I was there this past week, it wasn’t easy finding any Phragmatopoma that were submerged. I’ve written about Phragmatopoma before, so won’t go into details here. But look at all those fecal pellets!

Tentacles of the sandcastle worm, Phragmatopoma californica
2022-05-17
© Allison J. Gong

And last but not least, here are a couple of the many purple urchins (Strongylocentrotus purpuratus) out there. At Natural Bridges there’s a large pool fairly high in the mid-intertidal that is called the Urchin Pool because it contains dozens (hundreds?) of urchins. Most of them are burrowed into the soft rock. Those are sort of easy pickings. I like finding urchins in less-obvious places, like these.

Purple urchins (Strongylocentrotus purpuratus) tucked into burrows
2022-05-17
© Allison J. Gong

Urchins in the intertidal often cover themselves with bits of shell, small pebbles, and algae. This helps them retain water as the tide recedes. At a location where the rock is soft, such as Natural Bridges, many of the urchins have grown larger than the opening to their burrow and cannot leave to forage; these imprisoned urchins have to wait for pieces of algae to drift nearby, which they can grab with their tube feet and then transport to the mouth on the underside. So long as they don’t get pried out by otters, the urchins seem to do just fine.

I think that’s enough for now. I hope these photos give you some idea of what it was like out there a week and a half ago. The next excellent low tide series is in mid-June. Snapshot Cal Coast will be in full swing then, so get out there if you can!

When things are just a little too swell

Posted on by Allison J. Gong
Big waves breaking on beach, with cliffs on the right side

One of the things that I’ve been doing with my Ecology class since almost the very beginning is LiMPETS monitoring in the rocky intertidal. Usually we have a classroom training session before meeting in the field to do the actual work. This year we are teaching the class in a hybrid mode, with lecture material being delivered remotely, so we don’t have class meetings except for our field trips. The LiMPETS coordinator for the Monterey Bay region, Hannah, and I arranged to meet at our sampling site, where she would do a training session on the beach before we herded everyone out into the intertidal. It truly was a great plan! But the weather intervened and a spring storm blew through, bringing in a big swell. There was a high surf warning for our area the day of our scheduled LiMPETS work. Hannah and I conferred via email and decided that we’d still give it a shot, and at least the students would have an opportunity to learn about the LiMPETS program and practice with the datasheets and gear.

I arrived early to see how the surf was looking, and it was impressive. The waves were regularly covering our sampling location with whitewash, even as the tide was going out. When my co-instructor arrived and I showed him where the transect would lie, it was an easy decision to make to cancel the monitoring. But we would still be able to do the practice stuff, so we convened with Hannah on the bluff and she went into teacher mode.

College students standing in a circle, listening to instructor
Hannah (right) explaining the LiMPETS program
2022-04-22
© Allison J. Gong

We didn’t bother with the transect, but had groups of students work through some quadrats out on the intertidal bench, which you can just see in the background of the photo above. Hannah kept everyone out of the danger zone and we stressed the importance of having one member of each group keep an eye on the ocean at all times. We stayed mostly in the high zone, venturing down into the upper mid zone only when the tide was at its lowest. Even then, the big swells would surge up the channels and splash up onto the benches. Nobody got swept off, though, or even more than a teensy bit damp.

College students in the rocky intertidal
College students in the rocky intertidal
Students working in the high intertidal
2022-04-22
© Allison J. Gong

Most of the students left after what little work we had for them to do, and that gave me the freedom to poke around on my own and take pictures. I hadn’t had a chance to do this in a long time, and intended to make the most of a decent low tide that was almost wiped out by huge swell.

So here we go!

First up, the high-intertidal seaweeds:

Olive-green seaweed on rock, with mussels surrounding
Silvetia compressa
2022-04-22
© Allison J. Gong

And here’s a typical high intertidal community at Davenport Landing. Inhabitants include:

  • Several large clumps of rockweed (Silvetia compressa and Fucus distichus)
  • Several smaller bunches of tufty reds (Endocladia muricata)
  • Mussels (Mytilus californianus)
  • Many blotches of “tar spot alga” which is the encrusting tetrasporophyte phase of Mastocarpus papillatus
Clumps of olive-green seaweeds, dark red seaweeds, and mussels on rock
High intertidal community at Davenport Landing
2022-04-22
© Allison J. Gong

The water was pretty murky, so not great for underwater photography. Some of the shots turned out pretty well, though. The soft pale purple structures that you see in the photo below are papullae, used for gas exchange. You can see these only when the star is immersed.

Clumps of pale purple transparent tubes interspersed with white blotches
Aboral surface of the ochre star Pisaster ochraceus, showing papullae and spines
2022-04-22
© Allison J. Gong

The anemones were, as always, happy to be photographed. In this shot, the anemone was being photobombed by a turban snail.

Large green sea anemone and small purple snail in a tidepool
Green anemone (Anthopleura xanthogrammica) and black turban snail (Tegula funebralis)
2022-04-22
© Allison J. Gong

Here’s another typical intertidal assemblage:

Clump of sandy tubes with mussels, barnacles, and greenish-purple seaweed
Sandcastle worm (Phragmatopoma californica), iridescent alga (Mazzaella flaccida), gooseneck barnacles (Pollicipes polymerus), and mussels (Mytilus californianus)
2022-04-22
© Allison J. Gong
Gooseneck barnacles (Pollicipes polymerus)
2022-04-22
© Allison J. Gong

A couple of students stayed after the rest of the class had left. They were happy to see the nice fat ochre stars, and so many of them in one small area.

Ochre stars (Pisaster ochraceus)
2022-04-22
© Allison J. Gong

It’s always good to see so many big ochre stars. For this species, in the intertidal areas that I visit, sea star wasting syndrome (SSWS) no longer seems to be a problem. Fingers crossed! We’ll have to see what unfolds in the next months and years.

Glow

Posted on by Allison J. Gong

On this winter solstice, as we anticipate the return of light, I thought I’d write about a different kind of light.

Merriam-Webster defines fluorescence as “luminescence that is caused by the absorption of radiation at one wavelength followed by nearly immediate reradiation usually at a different wavelength and that ceases almost at once when the incident radiation stops”. It is a type of luminescence that occurs in both biological and non-biological objects. For example, mushrooms and scorpions are notably fluorescent, as are several minerals. Technically, to qualify as “fluorescent” an object can absorb any wavelength of radiation and re-radiate any other, although the re-radiated wavelength is usually longer than the absorbed wavelength.

We humans, with our three (and occasionally four) color photoreceptor types, can see only the tiny fraction of the electromagnetic spectrum that we call visible light. The visible light range (approximately 400-700nm) is bounded by UV on the short end and infrared on the long end. Other organisms have very different light perception capabilities. We know, for example, that insects can see in UV and pit vipers can see in infrared. And as for mantis shrimps, which have as many as 12 types of photoreceptors, we don’t yet understand how they see the world, but you can bet it’s nothing like the way we do. For practical purposes, fluorescence is most easily seen when an object absorbs UV light and re-radiates light of a longer wavelength that falls into the visible light range.

When you shine a UV light on one of these fluorescent objects, you see an apparent color change from whatever it looked like under visible light. This color change is most striking in the dark, because the fluorescent object will appear to glow. The same thing happens in daylight, but is obviously more difficult to see.

Here, let me show you. A few weeks ago I went to Natural Bridges to photograph the anemones, first under normal daylight conditions and then under UV light. I have a pretty wimpy UV flashlight, it turns out, but you can still see the fluorescence.

Here’s Anemone #1, under daylight:

Sea anemone in daylight
Sunburst anemone #1 (Anthopleura sola) at Natural Bridges
2021-12-07
© Allison J. Gong

And here’s Anemone #1 under UV light:

Sea anemone under UV light
Sunburst anemone #1 (Anthopleura sola) at Natural Bridges, under weak UV light
2021-12-07
© Allison J. Gong

Striking difference, isn’t it?

This is Anemone #2. It was getting dark by then, but this photo was also taken without flash and I did not increase exposure of the image.

Sea anemone
Sunburst anemone #2 (Anthopleura sola) at Natural Bridges
2021-12-07
© Allison J. Gong

And, under UV light:

Sea anemone under UV light
Sunburst anemone #2 (Anthopleura sola) at Natural Bridges, under weak UV light
2021-12-07
© Allison J. Gong

Here’s what’s going on. Pigment molecules in the anemones’ tissues are absorbing the UV radiation and re-radiating light in the visible range. It’s easier to see the fluorescence in Anemone #2 because it was much darker when I took that set of photos. Fluorescence still occurs during the day, but we can’t see it as well in the daylight. This is why our local bowling alley does their Atomic Bowling at night! They can dim the overhead lights, crank up the black lights, and let the tunes roll.

Incidentally, if you’ve ever wondered why so-called black lights are purple, there’s a reason for it. A true black light emits only UV light. UV light is invisible to us, hence the term “black”, as in pure darkness. UV lights that ordinary folks like us can buy are tinged purple so that we can see it. The purple isn’t UV, of course, but seeing the purple light keeps people from looking into the beam and frying their retinas from the actual UV radiation.

Sea anemones, of course, do not celebrate the solstice, but they do perceive it. They, and just about every other living thing, can sense the cyclical changes in day length as the year progresses. After tonight the days will start getting longer as we move through winter and towards spring. Personally, I cannot wait until we get the early morning low tides in the spring.

In the meantime, happy solstice, everyone!

Ready for battle

Posted on by Allison J. Gong

For some reason, many of the sunburst anemones (Anthopleura sola) in a certain area at Davenport Landing were geared up for a fight. I don’t know what was going on before I got there yesterday morning, but something got these flowers all riled up. We think of them as being placid animals, but that’s only because they operate at different time scales than we are used to. A paradox about cnidarians is that they don’t do anything quickly except fire off their stinging cells; that, however, they do with the fastest known cellular mechanism in the animal kingdom. Go figure.

Pale green sea anemone with slender feeding tentacles surrounding the oral disc. Below the ring of feeding tentacles there is a ring of thick club-shaped tentacles used for fighting.
Sunburst anemone (Anthopleura sola) with inflated acrorhagi
2021-06-27
© Allison J. Gong

What looks like an anemone wearing a tutu is actually an anemone ready to fight. The normal filiform feeding tentacles are easily recognized. But those club-shaped white tentacles below the ring of feeding tentacles are called acrorhagi. They are all about fighting. The tips are loaded with potent cnidocytes that usually aren’t used to catch food. They are used to fight off other anemones, and possibly predators.

Here’s another shot of the same animal, which shows how the feeding tentacles and acrorhagi are arranged in concentric rings:

Pale green sea anemone with slender feeding tentacles surrounding the oral disc. Below the ring of feeding tentacles there is a ring of thick club-shaped tentacles used for fighting.
Sunburst anemone (Anthopleura sola) with inflated acrorhagi
2021-06-27
© Allison J. Gong

So who would this anemone be fighting? This individual was the only one of its kind in the pool where it lives. I don’t know why its acrorhagi are inflated. I suppose they could be used to fend off a would-be predator, but I didn’t see any other animal in the pool that seemed a likely candidate.

But look at this duo:

Two pale green sea anemones with slender feeding tentacles surrounding the oral disc.The anemone on the right has inflated fighting tentacles. The animal on the left has fewer inflated fighting tentacles.
Sunburst anemones (Anthopleura sola) with inflated acrorhagi
2021-06-27
© Allison J. Gong

Now, clearly there is (or had been) something going on between these individuals. They both have their acrorhagi inflated. I’ve been looking at this photo for a while and can’t decide which is the aggressor. At first I assumed that the anemone on the right had initiated an attack on the other. But now I wonder if that is a defensive posture rather than an offensive one. That animal does seem to be more bent out of shape than the one on the left.

I’ve seen anemone fights before, and I’ve also seen anemones living side by side, tentacles touching, in apparently perfect amity. It’s very clear that they can coexist peacefully. Why, then, do they sometimes choose to fight? It’s important to point out that Anthopleura sola is an aclonal species. Unlike its congener A. elegantissima, whose primary mode of growth is cloning, each A. sola represents a unique genotype. With these anemones, whether or not two individuals fight is not determined by relatedness.

In a different pool these two anemones are sharing the carcass of a rock crab.

Sunburst anemones (Anthopleura sola)
2021-06-27
© Allison J. Gong

Maybe that third anemone at the top had also taken part in the feast, but at this point it seemed to be minding its own business. Given the demonstrated aggression of some A. sola, it would be interesting to know whether or not this trio ever fight amongst themselves. When we ‘ooh’ and ‘aah’ over them in the tidepools they look like passive flowers, and we forget that they are active predators. But we humans have access to the anemones’ home for only a few hours every month, and I have no doubt that they get up to all sorts of shenanigans when we’re not looking.

Serendipity, once again

Posted on by Allison J. Gong

Sometimes things just work out, through no fault of my own. In terms of good minus tides occurring in daylight hours, this weekend’s tides are the best we will have all season. Today (Saturday 29 May) is the third of five intertidal excursions I have planned. This morning I went up to Pistachio Beach to collect some things for the Seymour Center. I always feel a teensy bit apprehensive agreeing to collect for anybody but myself, because it is quite likely that I will get skunked and not be able to bring back what is needed. So usually I just agree to keep my eyes open for things that are on the wish list and make no promises.

The current wish list for the Seymour Center includes fishes. I’ve already brought them some sculpins and a clingfish, but small pricklebacks are also welcome. Pistachio is a popular place for people who fish for large pricklebacks. Apparently they (the pricklebacks) put up a good fight and make tasty eating. The usual way of fishing for them is poke-poling. I am not entirely sure how that works, but it involves a long pole and baited hooks. I think the idea is to lure a prickleback out from its hiding place at low tide, when it is sort of stranded away from open water. Adults get up to 70-80 cm long, and are as big around as my forearm.

Unlike the fishermen, I was fishing for young pricklebacks, hoping to find some that were about the length of my hand. Possessing the ideal set of characteristics for avoiding capture—a long eel-like body, small head, slimy coating, and the ability to augur really quickly into even the tiniest crack amongst the cobbles—these small fish led me on a merry chase for quite a while. However, the advantages that I have over even a wily prickleback are an enlarged cerebral cortex, opposable thumbs, and the dexterity to use both a dip net and a zip-loc baggie. When all was said and done I had two appropriately sized pricklebacks in my baggie, and two others had gotten away from me. Oh, and I did also bag another clingfish!

Having had that bit of success and not wanting to press my luck, I started poking around just for the hell of it, without any clear objective in mind. As I’ve said before, what we gain from a super low tide like this (-1.6 ft) is not only access to more real estate in the low intertidal, but more time to spend there before the tide returns. I took lots of photos, which I will present in chronological order. These will give you an idea of what it was like out there this morning.

Even the hike across the beach yielded something nice—this small stand of Postelsia palmaeformis, the sea palm. These poor junior kelps will be taking a beating with these spring tides rushing up and down. That’s the price they pay for living out there on those exposed rocky points.

Group of 6 sea palms on the beach
06:53 Postelsia palmaeformis
2021-05-29
© Allison J. Gong

The leather star Dermasterias imbricata isn’t one of the most common stars in the intertidal around here. It was one of the species that was hit pretty hard by the most recent outbreak of Sea Star Wasting Syndrome. We see one every so often, but they are nowhere as abundant as the ochre stars or bat stars.

07:10 Dermasterias imbricata
2021-05-29
© Allison J. Gong

Pistachio Beach isn’t the best place for large anemones, but of course there are some. This is one of the few big Anthopleura anemones that I saw today. There are many of the small cloning anemones, A. elegantissima, in the high intertidal, as well as the moonglow anemones, A. artemisia, in the mid and low sandy areas.

07:12 Anthopleura xanthogrammica
2021-05-29
© Allison J. Gong

I was so pleased to see my favorite red alga doing really well in the low zone! It is so pretty.

Red seaweed
07:29 Erythrophyllum delesserioides
2021-05-29
© Allison J. Gong

And at the same time I accidentally discovered a pretty big rock crab, which was tucked under a rock. For its species, this one was pretty calm and didn’t come at me with big claws up. It could be that this crab is a male, and is clasping a female beneath him. I didn’t check.

Dorsal view of a rock crab
07:29 Romaleon antennarium
2021-05-29
© Allison J. Gong

One of the things I found while turning over rocks to look for fish is this purple urchin:

Sea urchin with purple and green coloration
08:02 Strongylocentrotus purpuratus
2021-05-29
© Allison J. Gong

And a bit later, a nice healthy group of Dictyoneurum californicum. As these thalli age, they will develop longitudinal splits at the base of the blades. Right now they are young and crispy.

Blades of a brown seaweed with a waffle-like texture
08:15 Dictyoneurum californicum
2021-05-29
© Allison J. Gong

And who can resist such an exuberantly decorated limpet? Certainly not I! Reminds me of the fancy hats that ladies used to wear for Easter. Or Beach Blanket Babylon.

Limpet heavily fouled with encrusting and upright coralline algae
08:28 Limpet, probably Lottia sp.
2021-05-29
© Allison J. Gong

Chitons, the overlooked molluscs that reach peak abundance and diversity in the intertidal, can be very common along the coast. Species composition varies from site to site, though. Here at Pistachio Beach, the two species of Tonicella are very common. I found several of them on the undersides of rocks. This one is T. lokii.

Chiton with dark wavy lines on the shell plates and alternating pink and beige patches on the girdle
08:52 Tonicella lokii
2021-05-29
© Allison J. Gong

After two hours of catching fish and looking around, I was getting cold. Time to head back up and out. That took an additional half-hour or so, because I kept getting distracted by the algae. For example, look at how beautiful this Fucus is. And note the swollen tips, which mean this thallus is getting sexy. ‘Tis the season, after all.

Olive-green seaweed with wide dichotomous branches and swollen branch tips
09:15 Fucus distichus
2021-05-29
© Allison J. Gong

One of the other rockweeds, Pelvetiopsis limitata, was also very thick and abundant.

Olive-green seaweed with narrow dichotomous branches
09:19 Pelvetiopsis limitata
2021-05-29
© Allison J. Gong

The rockweeds share the high intertidal with a few species of red algae. The most common reds in this zone are the two (or however many there are) species of Mastocarpus, and Endocladia muricata.

Reddish-brown seaweed with wavy blades, covered with tiny bumps
09:21 Mastocarpus papillatus
2021-05-29
© Allison J. Gong

I always want to stop and look around in the high zone on my way down. Because when I walk past sights like this, it’s hard not to stay and study more closely. Then I remember that I can take as much time as I want in the high zone on the way out. This morning I took lots of photos of these reds and rockweeds.

How many different types of seaweed can you see?

09:24 High intertidal algal assemblage
2021-05-29
© Allison J. Gong

So there you have it, my morning summarized in about a dozen photos. I hope your Saturday was as enjoyable as mine was!

A snail’s pace

Posted on by Allison J. Gong

As we speed towards the summer solstice the days continue to get longer. The early morning low tides are much easier to get up for, as the sky is lightening by 05:30. Even so, when traveling an hour to get to the site, it’s nice when the low is later than that. This past Saturday the low wasn’t until 08:00. My parents were in Monterey for the weekend, so I decided it would be a good day to work the tide at the southern end of Monterey Bay, and then visit my parents. The Monterey Peninsula has some of the most spectacular tidepooling terrain in the region, and if I lived closer you can bet I’d know those sites better. Not that there is anything at all wrong with the sites on my end of the Bay and up the coast. But sometimes it’s good to get out of one’s comfort zone and explore the less well known.

Rocks and tidepools
Rocky intertidal at Asilomar State Beach
2021-05-15
© Allison J. Gong

So explore we did. It was cold and windy. The tide wasn’t all that low and the swell was up, so we didn’t get beyond the mid-tidal zone. My hip boots have deteriorated to the point that I have pinprick leaks at the seam where the boot part meets the leg part. Usually the tiny leaks don’t bother me, but when the water is cold I definitely feel the trickles. What all this means is that I didn’t get down into the low zone, which is fine. Biodiversity is highest in the mid zone anyway. The mediocrity of the low tide meant that I had to keep an eye out for sneaker swells, so less heads-down poking around and more scanning from above and then zooming in on individual items of interest.

One thing we noticed right away is that groups of Tegula funebralis, the black turban snail, were clumped together above the waterline of the high pools.

Black turban snails (Tegula funebralis)
2021-05-15
© Allison J. Gong

I’m trying to decide whether or not this is noteworthy. The pattern did catch my eye, but that might be only because it’s unusual (although not particularly interesting). It was a cold and drizzly morning, so the snails didn’t have to worry about desiccation. Was the clumping together benefiting the snails in any significant way? Hard to say.

The T. funebralis were also clumping together in the water! Here’s a large clump of Tegula shells in a pool.

Clump of black turban snails in a tidepool
Black turban snails (Tegula funebralis) and one hermit crab (Pagurus samuelis)
2021-05-15
© Allison J. Gong

Almost all of these are snails, but can you see the one that is a hermit crab?

Poor Tegula funebralis. It is so common that it is invisible and vastly underappreciated. I find them quite charming, though. There’s something about a grazing snail’s slow way of life that is very soothing. Not that you might not fall asleep waiting for them to do something interesting, but it is good to slow down to the pace of nature. Anyway, Tegula is one of my favorite animals, precisely because it is so unassuming and ignored. One of delightful things about Tegula funebralis is when it plays host to Crepidula adunca. I’ve written about the biology of C. adunca before and don’t want to rehash that here. I just wanted to show off my favorite photo of this trip to Asilomar:

Black turban snail with two attached slipper snails
Black turban snail (Tegula funebralis) wearing two slipper snails (Crepidula adunca)
2021-05-15
© Allison J. Gong

I don’t know why I like this photo so much. It certainly isn’t the best shot I’ve ever taken. There isn’t any vibrant color at all. The subjects are the same color as the background. But it works for me.

When it comes to a snail’s pace, you can’t find anything slower than Thylacodes. That’s because Thylacodes squamigerus is the snail that lives in a calcareous tube. Much like a barnacle, or the serpulid worms that have similar tubes, Thylacodes makes one decision about where to live and lives there for the rest of its life. I see Thylacodes at places like Pigeon Point up north, but they are much more abundant on the Monterey Peninsula.

Tube snail (Thylacodes squamigerus)
2021-05-15
© Allison J. Gong

And the snail winners in the Most Likely to be Overlooked have got to be the littorines. These little snails (most of which are smaller than 15 mm) live in the highest intertidal, where they get splashed by the ocean just often enough to keep their gill sufficiently moist. They are never entirely submerged, but they do tend to gather in cracks, even the tiniest of which will hold water longer than a flat rock surface.

Littorines (Littorina keenae) in the splash zone
2021-05-15
© Allison J. Gong

If you look closely at the photo above, you might see pairs of mating snails. Given where they live, high up in the intertidal where they are rarely covered by water, broadcast spawning isn’t a viable option for the littorines. They have to copulate. There are, I think, eight copulating pairs in this group of ~30 snails.

Copulating pairs of Littorina keenae
2021-05-15
© Allison J. Gong

Because Littorina‘s habitat makes broadcast spawning an unfeasible option, the snails must lay eggs. But the splash zone isn’t a very friendly place for the eggs of marine animals. The littorines lay eggs in gelatinous masses in crevices or depressions where water will remain. After a week or so of development, the egg mass dissolves as it gets splashed, and veliger larvae emerge. They recruit back to the intertidal after spending some period of time in the plankton.

When all is said and done it’s difficult to make the claim that snails live exciting lives. Nonetheless, they are interesting animals. The diversity of morphology and lifestyle we see in the intertidal snails makes them eminently worthy of study and appreciation. I like to think that, as biologists once again “discover” the usefulness of natural history, students will be encouraged to fill in some of the gaps in our understanding of these and other abundant animals.