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One of the best things about teaching is the opportunity to keep learning. Case in point: yesterday I attended an all-day teacher training session for the LiMPETS program, so that I can have my Ecology students participate in a big citizen science project in the rocky intertidal later this spring. In the Monterey Bay region LiMPETS is organized and run out of the Pacific Grove Museum of Natural History, where yesterday's training took place. LiMPETS has two ongoing citizen science projects, one looking at populations of mole crabs (Emerita analoga) on sandy beaches and the other monitoring population of several invertebrate and algal species on rocky shores. Of course, my interests being what they are I signed up for the rocky intertidal monitoring project.

We spent the morning learning about the history of the program and how to identify the organisms that are monitored, then after lunch went out to Point Pinos to collect some data and work through the process that we need to teach to our students. The day before we'd had a high surf advisory on the coast, and yesterday the swell was still big. We hiked out to the study site and set up the transect line, which runs from the top of a rock through the entire range of tidal heights to the low intertidal.

LiMPETS study site at Point Pinos. 6 February 2016 © Allison J. Gong
LiMPETS study site at Point Pinos.
6 February 2016
© Allison J. Gong
One of our instructors, the intrepid Emily, sets the transect line. 6 February 2016 © Allison J. Gong
One of our instructors, the intrepid Emily, sets the transect line.
6 February 2016
© Allison J. Gong

Where Emily is standing is about 10 meters along the transect line. The monitoring protocol calls for sampling at every meter on the transect. One of the other teachers, Phaedra, and I were the only ones wearing hip boots, so we volunteered to work at the lowest spot. We thought we'd start with the 10-meter quadrat and hopefully get down to the 11-meter quadrat once the tide receded a bit more. Then we got hit by a few big waves and decided that discretion is the better part of valor and gave up. It was a pretty easy decision to make, especially after the quadrat got washed away and we had to go fetch it when the waves brought it back.

Field gear. 6 February 2016 © Allison J. Gong
Field gear.
6 February 2016
© Allison J. Gong

All told the group collected eight quadrats of data. We had a little time to poke around (i.e., take pictures) before heading back to the museum for data entry.

A gorgeous chiton! 6 February 2016 © Allison J. Gong
A gorgeous chiton! I don't know which species it is.
6 February 2016
© Allison J. Gong
Codium fragile, a filamentous green alga. 6 February 2016 © Allison J. Gong
Codium fragile, a filamentous green alga.
6 February 2016
© Allison J. Gong

Codium is an interesting alga. These cylindrical structures are composed of many filaments, which in turn contain multi-nucleate cells. Yes, the cells contain multiple nuclei. Codium fragile has the common name "dead man's fingers," I suppose because. . . well, I actually have no idea. As far as I can tell they don't feel anything like a dead man's fingers, or the way I imagine a dead man's fingers would feel.

There were quite a few empty abalone shells scattered among the rocks. As we were hiking out I found this shell. When I tried to pick it up I found that it was still alive, and well stuck to the rock. This is a very good sign, as the black abs have been suffering from withering syndrome, in which the animal gradually loses its ability to hang on.

Haliotis cracherodii, the black abalone, wearing a few barnacle friends. 6 February 2016 © Allison J. Gong
Haliotis cracherodii, the black abalone, wearing a few barnacle friends.
6 February 2016
© Allison J. Gong

All in all, this workshop was a lot of fun. If I have to give up an entire Saturday to do training, it couldn't get much better than spending at least part of it in the intertidal. And Point Pinos is such a fabulous intertidal site that I certainly wouldn't turn down an opportunity to explore there again.

2

The new moon is tonight, which of course means that we are in spring tides. Yesterday afternoon my friend and colleague Scott joined me for my first visit to the intertidal in 2016. And where to go for this inaugural field excursion of the new year, but to Franklin Point? Low tide was at 15:53 yesterday, so we met up at 14:00, stopped to fill up the gas tank, and headed up the coast. Expecting it to be crazy windy as afternoons tend to be on the coast, I had dressed in extra layers. Scott and I were surprised to emerge from the car and find it wasn't windy at all, so even though the air temperature was cool at least we didn't have to deal with any significant amount of windchill factor.

Hiking over the dunes we saw Unusual Thing #1--a bridal photo shoot. A couple of stretches of the trail are covered by a boardwalk, and on the first of these we encountered a bride decked out in full regalia--wedding dress, flowers, hair, make-up--and two photographers. They were very nice and let us pass through in our decidedly inelegant boots and field gear. I didn't think it would be very nice to take their picture. However, I did think that they'd lucked out and gotten a great day for photography: the aforementioned lack of wind meant that the bride wasn't freezing in her slip of a wedding dress, and the afternoon light was flat so there were no shadows or harsh glare.

Descending onto the beach we came across Unusual Thing #2--an elephant seal.

Male elephant seal (Mirounga angustirostris) hauled out on the beach at Franklin Point. 8 January 2016 © Allison J. Gong
Male northern elephant seal (Mirounga angustirostris) hauled out on the beach at Franklin Point.
8 January 2016
© Allison J. Gong

It is e-seal haul-out time at Año Nuevo State Park a few miles down the road from Franklin Point, and I've seen them on the beach a few times before. This was the first time I'd seen an adult male, though, and he was HUGE! Without being stupid and going over to stand next to this animal it's hard to depict how large he is, and unfortunately there wasn't anything in the vicinity to give a sense of scale. So trust me, or look it up for yourself, male elephant seals are ginormous. This big guy was taking a siesta, and we could hear him snoring. He did wake up and lift his head to look at us, but we gave him plenty of room as we walked past and he returned to his nap.

One of the reasons I wanted to see Franklin Point after the El Niño storms of the past week was to see how much sand had been washed away from the beach. Sand typically accumulates on California coastal beaches during the dry storm-less months of summer and autumn, only to be flushed away by storms the following winter. After a particularly violent storm or a series of storms occurring in a short time, very large amounts of sand can be removed from a beach. For the past four years we haven't had much of a winter storm season (hence the awful drought) and the beach at Franklin Point has been tall and gently sloped. I'd grown accustomed to this state of affairs, which makes what we saw yesterday qualify as Unusual Thing #3--rocks that had been covered with sand for years and are now exposed.

To set the stage, here's a picture that I took on an afternoon low tide last year on 17 March 2015:

Franklin Point beach on 17 March 2015. © Allison J. Gong
Franklin Point beach on 17 March 2015.
© Allison J. Gong

And here's yesterday's photo from the same general area:

Franklin Point beach on 8 January 2016. © Allison J. Gong
Franklin Point beach on 8 January 2016.
© Allison J. Gong

Can you see how much steeper the beach is in yesterday's photo? And those rocks on the left side? They are not visible in the photo from last spring because they were under sand!

Here's a closer look at the newly exposed rocks:

Newly exposed rocks at Franklin Point. 9 January 2016 © Allison J. Gong
Bare rocks at Franklin Point.
9 January 2016
© Allison J. Gong

You can see exactly how high the sand was last summer. What's really exciting is that these rocks represent pristine habitat that has yet to be exploited. I can look at primary ecological succession this spring! Well, at least until the sand returns and buries the rocks again.

As we meandered among the rocks in the intertidal, Scott and I both noticed an abundance of abalone shells. Fairly early on we spotted this black ab shell lying emersed above the water line:

Black abalone (Haliotis cracherodii) at Franklin Point. 8 January 2016 © Allison J. Gong
Black abalone (Haliotis cracherodii) at Franklin Point.
8 January 2016
© Allison J. Gong

Turning the shell over we saw Unusual Thing #4--an abalone showing signs of withering syndrome:

Ventral view of a black abalone (Haliotis cracherodii) at Franklin Point. 8 January 2016 © Allison J. Gong
Ventral view of a black abalone (Haliotis cracherodii) at Franklin Point.
8 January 2016
© Allison J. Gong

We were actually surprised to see that the animal was alive. Healthy living abalone are firmly attached to rocks, tucked into crevices. This one wasn't attached to anything, just lying on the sand. We picked it up, turned it over, and found the body of the animal shriveled up and filling up only about half of the space it should have occupied. It didn't respond to gentle pokes but wasn't dead yet, or at least not dead enough to pass the stink test for deadness.

Withering syndrome is a bacterial disease that inhibits digestive function in abalone. To stave off starvation the infected animal begins to digest its own body tissues. As a result the entire body shrinks and eventually the foot can no longer stick to rocks. In California it affects black abs and red abs (H. rufescens). Until the recent years of warmer-than-usual water black abs (H. cracherodii) had been most common in southern California, but I've been seeing more of them in the past few years. Now it looks like the disease that plagues them has accompanied them up the coast. It's not surprising, given the current El Niño conditions.

This gives me another thing to keep an eye out for in my intertidal excursions. I'll start keeping track of abalone and see if withering syndrome becomes more prevalent. Might as well start with this afternoon's low tide!

In defiance of post-nasal drip and an ominous tickle at the back of my throat, I got up early again this morning and went out on the low tide. I skipped yesterday's low tide in favor of getting a little more sleep, thinking that it would help me fight off this incipient summer cold, but I didn't want to miss two of the three intertidal trips I had planned for this weekend. So I made the quick drive up to Davenport Landing, where low tide was at 06:4o.

The first thing I noticed when I got down to the beach was that the algae have started piling up. There were drifts that I sank into almost knee-deep. Fortunately they hadn't really started decomposing yet, so the smell wasn't too bad. That will change if it stays warm and the high tides don't wash any of the algal detritus back out to sea.

Looking back at Davenport Landing beach, from the north. 2 August 2015. © Allison J. Gong
Looking over piles of algal detritus towards Davenport Landing beach, from the north. 2 August 2015.
© Allison J. Gong

It's treacherous stuff, that algal duff. It covers up deep holes and slippery rocks, so each footstep becomes an adventure. Because it has been so warm I had considered going out in shorts and surf booties, but more than once this morning I was glad to be wearing my hip boots.

It was a busy day for nemertean worms. Nemerteans are unsegmented, slimy, predatory worms that feed by shooting out a proboscis and wrapping it around prey. In some nemerteans the proboscis is armed with a stylet that injects toxins to help immobilize prey, which are often small polychaete (segmented) worms. Nemerteans are not uncommon, but are often inconspicuous and easily overlooked. None of the ones that I saw today were actively hunting.

Nemertean worm (Paranemertes peregrina) at Davenport Landing, 2 August 2015. © Allison J. Gong
Nemertean worm (Paranemertes peregrina) at Davenport Landing, 2 August 2015.
© Allison J. Gong

As you can see, the body of this worm is not segmented. However, it has the same body wall musculature that you'd find in the polychaetes, which are the segmented marine worms. It uses the muscles to alternately contract and elongate the body and move forward. In most nemerteans neither the head nor the tail end is particularly distinguishable, but in worms you can usually tell the anterior (head) end by the direction of locomotion. Here's a video:

Continuing to play with the 'microscope' setting on my camera, I took this picture of a chiton (Mopalia muscosa):

Mopalia muscosa at Davenport Landing, 2 August 2015. © Allison J. Gong
Mopalia muscosa at Davenport Landing, 2 August 2015.
© Allison J. Gong

I'm still learning how to make that compromise between super-macro and depth of field on this setting. The chiton in the above photo is about 4 cm long so I wasn't zoomed in terribly far, and I like how it is in focus but some of the other critters are as well.

On the reef to the north of Davenport Landing beach there's a large pool that gets to a bit more than knee deep on me, and is cut off from the ocean during low tide. This pool has proven to be a great place to practice my underwater picture taking. The past couple of times I've come out here I've seen schools of surfperches swimming in this pool. The school contains large individuals (about as long as my hand) and smaller ones that I think are the babies of the big ones. I haven't been able to catch one--for some reason I've never included a dipnet in my collecting gear, preferring to catch sculpins with my hands--but I think they are shiner surfperches (Cymatogaster aggregata).

Before trying to photograph the fishes underwater, I shot some video from above:

It turns out that photographing fish underwater isn't as easy as I thought it might be. Surfperches are pretty skittish and I couldn't get as close to them as I wanted. However if I stood still for a minute or so they forgot about me and would resume their normal behavior. In the meantime I did sort-of-accidentally take some cool pictures of the pool from below the surface.

Large tidepool at Davenport Landing, 2 August 2015. © Allison J. Gong
Large tidepool at Davenport Landing, 2 August 2015.
© Allison J. Gong
Large tidepool at Davenport Landing, 2 August 2015. © Allison J. Gong
Large tidepool at Davenport Landing, 2 August 2015.
© Allison J. Gong

And finally, fish!

Shiner surfperches in large tidepool at Davenport Landing, 2 August 2015. © Allison J. Gong
Shiner surfperches (Cymatogaster aggregata) in large tidepool at Davenport Landing, 2 August 2015.
© Allison J. Gong

Last, but certainly not least, in this same large pool I found several anemones. The most brightly colored are the Anthopleura artemisia. I love how their tentacles can be such a vibrant translucent orange or purple, or the oral disc can have that deep saturated red color.

Anthopleura artemisia at Davenport Landing, 2 August 2015. © Allison J. Gong
Anthopleura artemisia at Davenport Landing, 2 August 2015.
© Allison J. Gong
Anthopleura artemisia at Davenport Landing, 2 August 2015. © Allison J. Gong
Anthopleura artemisia at Davenport Landing, 2 August 2015.
© Allison J. Gong

Hard to believe that these animals are the same species, isn't it? Then again, to an alien scientist studying humans it might be hard to believe that a Viking, an Australian aboriginal and I (an Asian-American) are the same species. It's all simply a matter of perspective.

3

This morning I went on a solo trip to one of my favorite intertidal sites up the coast a bit. I've been busy with stuff at the marine lab and my house is a construction zone this summer so it was really nice being alone in nature for a couple of hours before most people had gotten out of bed.

I didn't find what I was looking for but did see some great stuff that I wasn't looking for, which is just as rewarding.

The approach to the beach over the dunes is always spectacular even on a gloomy morning. I find this color palette very soothing.

The hike over the dunes, 5 June 2015. © Allison J. Gong
The hike over the dunes, 5 June 2015.
© Allison J. Gong

The site itself is rocky with a sandy bottom. Depending on the severity of recent storm action there can be more or less sand. Winter storms wash sand away, while in the summer the sand tends to accumulate and can bury the rocks to surprising depths.

Surfgrass bed (Phyllospadix sp.) and rocks at Franklin Point, 5 June 2015. © Allison J. Gong
Surfgrass bed (Phyllospadix sp.) and rocks at Franklin Point, 5 June 2015.
© Allison J. Gong

It may be an optical illusion, but when I'm scrunched down in amongst the rocks it appears that the waves are breaking at heights quite a bit above my head. Most of the water's force is dissipated as the waves wash over the rocks, and unless I've wandered out too far, by the time it gets to me all I need to worry about is whether the surge will overtop my boots. Which has indeed happened and makes for a cold squelchy morning.


And now for some happy snaps!

A small mid-intertidal pool at Franklin Point, 5 June 2015. © Allison J. Gong
An example of intertidal biodiversity at Franklin Point. The most conspicuous organisms are Ulva (sea lettuce), coralline algae (the pink stuff), small acorn barnacles, the tube-dwelling worm Phragmatopoma californica, and small anemones in the genus Anthopleura. 5 June 2015.
© Allison J. Gong
I love my hip boots!  © Allison J. Gong
I love my hip boots!
© Allison J. Gong
Pagurus hirsutiusculus hermit crab in shell of the snail Olivella biplicata, 5 June 2015. © Allison J. Gong
Pagurus hirsutiusculus hermit crab in shell of the snail Olivella biplicata, 5 June 2015.
© Allison J. Gong
A beautifully camouflaged kelp crab (Pugettia producta) hiding in plain sight, 5 June 2015. © Allison J. Gong
A beautifully camouflaged kelp crab (Pugettia producta) hiding in plain sight, 5 June 2015.
© Allison J. Gong

Because, really, doesn't everybody have a favorite red alga? This is mine. It presses gorgeously and is so damn beautiful!

Erythrophyllum delesserioides, 5 June 2015. © Allison J. Gong
Erythrophyllum delesserioides, 5 June 2015.
© Allison J. Gong

At one point I saw a worm-like thing thrashing around in a shallow pool. Turns out it was a polychaete worm, probably in the genus Nereis, doing epic battle with a predatory nemertean worm (Paranemertes peregrina). By the time I figured out what was going on and stuck my camera in the water the interaction had more of less come to an end. The polychaete did get away without apparent damage, but it was moving pretty slowly afterward. In this video Nereis is the segmented worm that's doing all the wiggling, and Paranemertes is the purple and beige unsegmented worm that you can sort of make out in the top of the frame. I wish I had been swifter on the uptake with the camera.


And the pièce de résistance for this trip:  A little sea hare! This guy was so small (about 2.5 cm long) that at first I thought it was a clump of red algae. Then I saw the little rhinophores (those ear-like projections that give them their common name) and recognized it as a sea hare. Amazingly cute!

A little sea hare (Aplysia sp.), 5 June 2015. © Allison J. Gong
A little sea hare (Aplysia sp.), 5 June 2015.
© Allison J. Gong

I was lucky enough to capture some video of this critter crawling around.

Aside from the rhinophores it doesn't look hare-like at all, does it? I wonder about common names sometimes.

All in all, it was a great morning. An early morning low tide is the best reason I can think of to crawl out of bed at 04:30!

4

Answer:  When it's a snail! Yes, there are snails that secrete and live in white calcareous tubes that look very similar to those of serpulid polychaete worms. Here, see for yourself:

Serpula columbiana, a serpulid polychaete worm, at Point Piños, 9 May 2015. © Allison J. Gong
Serpula columbiana, a serpulid polychaete worm, at Point Pinos, 9 May 2015.
© Allison J. Gong

The worms secrete calcareous tubes that snake over whatever surface they're attached to. When the worm is relaxed, it extends its delicate pinnate feeding tentacles and uses them to capture small particles to eat; they are what we call suspension feeders.

Serpula columbiana polychaete worms, Seymour Marine Discovery Center, 11 May 2015. © Allison J. Gong
Serpula columbiana polychaete worms, Seymour Marine Discovery Center, 11 May 2015.
© Allison J. Gong

But there are gastropods that secrete calcareous tubes, too. They are the vermetid snails, the local species of which is Thylacodes squamigerus. This is one of my favorite animals in the low intertidal, probably because it is so delightfully un-snail-like.

There are three individuals of T. squamigerus in this photo:

The vermetid snail Serpulorbis squamigerus at Point Piños, 9 May 2015. © Allison J. Gong
The vermetid snail Thylacodes squamigerus at Point Pinos, 9 May 2015.
© Allison J. Gong
Serpulorbis squamigerus at Point Piños, 9 May 2015. © Allison J. Gong
Thylacodes squamigerus at Point Pinos, 9 May 2015.
© Allison J. Gong

Thylacodes is also a suspension feeder, but it gathers food in a very different way. When submerged, it spins out some sticky mucus threads that catch suspended particles, then reels in the threads and eats them.

So how would you tell these animals apart if you see them? Here's a hint:  Look at the tubes themselves.

I invite you to use the comments section to tell me how you'd distinguish between Serpula and Thylacodes.

This morning I took a small group of Seymour Center volunteers on a tidepooling trip to Point Piños (see red arrow in the photo below). Point Piños is a very interesting site. It marks the boundary between Monterey Bay to the right (east) of the point and the mighty Pacific Ocean to the left (west).

Map of Monterey Bay. Red arrow indicates Point Pinos.
Map of Monterey Bay. Red arrow indicates Point Piños.
Point Pinos, 9 May 2015. © Allison J. Gong
Point Piños, 9 May 2015.
© Allison J. Gong

As is my usual habit, we began our exploration on the Pacific side of the point. Almost immediately, Victoria found an octopus! And a couple of meters away, she found another one!

Octopus rubescens at Point Pinos, 9 May 2015. © Allison J. Gong
Octopus rubescens at Point Piños, 9 May 2015.
© Allison J. Gong

As we approach the summer solstice, the algae and seagrasses are at their most lush. Point Piños is a fantastic site for algal diversity; every time I come here I want to take some back with me so I can study it at the lab. Alas, collecting at Point Piños is not allowed even for someone (like me) who holds a valid scientific collecting permit.

Beds of Phyllospadix scouleri at Point Pinos, 9 May 2015. © Allison J. Gong
Beds of Phyllospadix scouleri (surf grass) at Point Piños, 9 May 2015.
© Allison J. Gong
Macroalgae at Point Pinos, 9 May 2015. © Allison J. Gong
Macroalgae at Point Piños, 9 May 2015.
© Allison J. Gong

And yes, that log-like object towards the upper-left corner is a harbor seal (Phoca vitulina). A handful of seals were hauled out on the rocks.

However, I was much more interested in the invertebrates. I wasn't looking for anything specific, but in the back of my mind I was keeping track of certain nudibranchs and looking for small stars.

We did see many Patiria miniata (bat stars) in the 1-2 cm size range. Most of them were a bright orange-red color, but some were beige, yellow, or blotchy. There was one large (bigger than my outstretched hand) Pisaster ochraceus that was intensely orange. And Point Piños is always a good spot to see many of the six-armed stars in the genus Leptasterias.

Patiria miniata (bat star), about 1.5 cm in diameter, 9 May 2015. © Allison J. Gong
Patiria miniata (bat star), about 1.5 cm in diameter, at Point Piños, 9 May 2015.
© Allison J. Gong
Large healthy Pisaster ochraceus (ochre star), 9 May 2015. © Allison J. Gong
Large healthy Pisaster ochraceus (ochre star) at Point Piños, 9 May 2015.
© Allison J. Gong
Leptasterias sp., one of the six-armed stars, 9 May 2015. © Allison J. Gong
Leptasterias sp., one of the six-armed stars, at Point Piños,  9 May 2015.
© Allison J. Gong

In terms of nudibranchs there were many Doriopsilla albopunctata, a yellow dorid with tiny white spots. We saw quite a few of them crawling around on the emersed surf grass, as well as in pools. And of course Okenia rosacea (Hopkins' rose) was there, although not in the huge numbers I was expecting.

Doriopsilla albopunctata at Point Piños, 9 May 2015. © Allison J. Gong
Doriopsilla albopunctata at Point Piños, 9 May 2015.
© Allison J. Gong
Okenia rosasea (Hopkins' rose nudibranch) at Point Piños, 9 May 2015. © Allison J. Gong
Okenia rosasea (Hopkins' rose nudibranch) at Point Piños, 9 May 2015.
© Allison J. Gong

In the low zone I saw a few thalli of the intertidal form of Macrocystis pyrifera, the giant kelp that forms the forests that the California coast is famous for. I'd seen this intertidal form named Macrocystis integrifolia, but it appears that now the two forms (intertidal and subtidal) are both considered to be M. pyrifera. To my eye, the intertidal form differs morphologically by having rounder pneumatocysts (floats) and a holdfast that is less dense than the subtidal form.

Macrocystis pyrifera (giant kelp) growing intertidally at Point Piños, 9 May 2015. © Allison J. Gong
Macrocystis pyrifera (giant kelp) growing intertidally at Point Piños, 9 May 2015.
© Allison J. Gong

Hermit crabs are diverse and abundant at Point Piños. Here's an example of Pagurus samuelis, the blue-banded hermit crab; even when you can't see the blue bands on the legs, the bright red antennae are a major clue to this crab's identity.

Pagurus samuelis (blue-banded hermit crab) at Point Piños, 9 May 2015. © Allison J. Gong
Pagurus samuelis (blue-banded hermit crab) at Point Piños, 9 May 2015.
© Allison J. Gong

When we climbed over the point to the Monterey Bay side, I found two of these little gastropod molluscs, which I didn't recognize. They are about 1 cm long, with a brown lumpy mantle that can covers the shell, which is pinkish in color. After putting it out on Facebook that I needed help with the ID, a bunch of friends and friends of friends chimed in (thanks John, Rebecca, Barry, and David!) and I was able to determine that these little guys are Hespererato vitellina:

Hespererato vitellina (appleseed Erato snail) crawling on Phyllospadix scouleri (surf grass) at Point Piños, 9 May 2015. © Allison J. Gong
Hespererato vitellina (appleseed Erato snail) crawling on Phyllospadix scouleri (surf grass) at Point Piños, 9 May 2015.
© Allison J. Gong

On our way back up the beach we noticed long windrows of Velella velella, the by-the-wind sailors, washed up. While most of them were faded and desiccated, there were enough freshly dead ones that were still blue, which may have washed up on the previous high tide.

Windrows of Velella velella (by-the-wind sailor) washed up on the beach at Point Piños, 9 May 2015. © Allison J. Gong
Windrows of Velella velella (by-the-wind sailor) washed up on the beach at Point Piños, 9 May 2015.
© Allison J. Gong

All in all, a very satisfactory morning. I saw things I expected to see, some things I didn't quite expect but wasn't surprised to see, and some things I'd never seen before. That Hespererato vitellina was completely new to me, which is always exciting.

Next up:  What kinds of things live in white calcareous tubes?

2

This morning I went here (see arrow):

Natural Bridges State Beach, viewed from Long Marine Lab, 4 May 2015. © Allison J. Gong
Natural Bridges State Beach, viewed from Long Marine Lab, 4 May 2015.
© Allison J. Gong

See how it's covered in water? I took this picture at about 13:00, probably right at high tide. And of course when I was out there this morning at 06:00, it was low tide. It wasn't the greatest of low tides but it allowed me to see what I needed to see and have a front-row seat watching the early morning surfers going up and down on the big swell that's blowing in.

Obviously, visits to the intertidal need to be timed with the tide cycle. At this time of the year we get our lowest spring tides in the morning every two weeks or so, which is great for me because I am a creature of the morning. I can get up hours before the sun rises, but don't ask me to do anything that requires any intense brain activity after about 21:30.

Low tide this morning was at 05:29, when it was still almost full dark. There was plenty of light to see by the time I got out to the rocks. The tide wasn't very low and the swell was big, a combination that makes for some pretty spectacular wave watching. Here's a view towards the marine lab from my intertidal bench; look at all that frothy water!

View of Terrace Point from Natural Bridges State Beach, 4 May 2015. © Allison J. Gong
View of Terrace Point from Natural Bridges State Beach, 4 May 2015.
© Allison J. Gong

So the water was big and the tide was mediocre, but it was still a glorious morning. Where I was the bench looked like this:

Looking seaward, Natural Bridges State Beach, 4 May 2015. © Allison J. Gong
Looking seaward, Natural Bridges State Beach, 4 May 2015.
© Allison J. Gong

What a difference seven hours can make! See that tiny black dot in the ocean? That's a surfer. While I was out there none of the three surfers I was watching did any actual surfing.

I can't seem to stop taking pictures of anemones:

A baby Anthopleura sola, measuring about 1.5 cm in diameter, 4 May 2015. © Allison J. Gong
A small Anthopleura sola, measuring about 1.5 cm in diameter, 4 May 2015.
© Allison J. Gong
Anthopleura xanthogrammica, 4 May 2015. © Allison J. Gong
Anthopleura xanthogrammica, 4 May 2015.
© Allison J. Gong
Anthopleura sola adult, 4 May 2015. © Allison J. Gong
Anthopleura sola adult, 4 May 2015.
© Allison J. Gong

My prize of the day appeared as I was walking back. I happened to look down at the right time and saw this little guy:

Little octopus in tide pool at Natural Bridges State Beach, 4 May 2015. © Allison J. Gong
Little octopus in tide pool at Natural Bridges State Beach, 4 May 2015.
© Allison J. Gong

I was able to watch the octopus for a couple of minutes. Its mantle was about 3 cm tall, and I'd guess that all spread out the animal was perhaps a bit larger than the palm of my hand. When I got up to move around to the other side of the pool for a different camera angle, the octopus oozed underneath the mussels and just disappeared.

Before it vanished I was able to catch it in the act of breathing.

Although it looks like a head, given the position of the animal's eyes, the part of the animal that's pulsating is the mantle. The visceral mass and gills are contained in the space enclosed by the mantle; not surprisingly, this space is called the mantle cavity. The octopus flushes water in and out of the mantle cavity to irrigate its gills. When it wants to swim it closes off the opening to the mantle and forces water out through a funnel which can be rotated 360° so it can jet off in any direction. But this time the octopus didn't use jet propulsion. It just oozed away.

Yesterday I drove up the coast to Pigeon Point to do a little poking around. I had originally planned to search for little stars, survivors that had made it through the most recent outbreak of wasting syndrome. But I got distracted by other things and gave up on the stars, for now. I need to do some thinking about the best way to find tiny animals in a very complex 3-dimensional habitat.

I did spend quite a bit of time turning over rocks in tidepools. The most common critters I found were the usual suspects--porcelain crabs, limpets, snails, the odd sculpin or two, and chitons. One rock yielded a gold mine: five chitons of a species I didn't recognize (which doesn't mean I haven't seen it before, just that I didn't immediately know its name) that demonstrated a most interesting behavior.

Stenoplax heathiana, on underside of rock, 31 January 2015. Photo credit:  Allison J. Gong
Stenoplax heathiana, on underside of rock, 31 January 2015.
© Allison J. Gong

I turned the rock over and watched as the chitons ran away from the exposed surface onto the other side. Yes, RAN. I've never seen a chiton do anything this fast. Chitons, for the most part, lead apparently inactive lives. When we do get to see them in their natural setting, at low tide, they are usually scrunched down hard on the rock waiting for the water to come back. Obviously they are much more active when covered with water, but we don't get to see them then. In the lab, where they can be immersed all the time unless they crawl up the walls, they do wander around a bit; however, to see a chiton do much of anything requires time-lapse photography.

Don't believe that a chiton can run? Well, get a load of this:

This is in real-time, not sped up. Watch the chiton push a limpet and the snail out of the way. Okay, I'll grant that a limpet and a snail are not the strongest obstacles one could face when trying to flee from the light. But you can't deny that this chiton seems to be feeling a sense of urgency.

This species, Stenoplax heathiana, spends its days buried in sand on the underside of rocks. It comes out to feed at night, not on algal scums as most chitons do, but on bits of algae that drift by and get caught between rocks. Apparently the chiton can be found exposed in the very early morning. I'm going to have to try finding some this spring when we get our morning low tides back.  Anybody want to come with me?

 

The temperate rocky intertidal is about as colorful a natural place as I’ve seen. Much of the color comes from algae, and in the spring and early summer the eye can be overwhelmed by the emerald greenness of the overall landscape due to Phyllospadix (surf grass, a true flowering plant) and Ulva (sea lettuce, an alga). However, close observation of any tidepool reveals that the animals themselves, as well as smaller algal species, are at least as colorful as the more conspicuous surf grass and sea lettuce.

Take the color pink, for example. Not one of my personal favorites, but it is very striking and sort of in-your-face in the tidepools. Maybe that’s because it contrasts so strongly with the green of the surf grass. In any case, coralline algae contribute most of the pink on a larger scale. These algae grow both as encrusting sheets and as upright branching forms. They have calcium carbonate in their cell walls, giving them a crunchy texture that is unlike that of other algae. They grow both on large stationary rocks and smaller, easily tumbled and turned over rocks.

A typical coralline “wall” looks like this:

Coralline rock with critters, 18 January 2015.  Photo credit:  Allison J. Gong
Coralline rock with critters, 18 January 2015.
© Allison J. Gong

Mind you, this “wall” is a bit larger than my outspread hand. The irregular pink blotches are the coralline algae. Near the center of the photo is a chiton of the genus Tonicella; its pink color comes from its diet, which is the same coralline alga on which it lives. The most conspicuous non-pink items on this particular bit of rock are the amorphous colonial sea squirt (shiny beige snot-like stuff) and the white barnacles on the right.

What really caught my eye today were the sea slugs Okenia rosacea, known commonly as the Hopkins’ Rose nudibranch. Now, it is very easy to love the nudibranchs because they are undeniably beautiful. The fact of the matter is that they are predators, and some of them eat my beloved hydroids, but that’s a matter for another post. Today I saw dozens of these bright pink blotches dotting the intertidal, both in and out of the water:

Okenia rosacea, the Hopkins' Rose nudibranch, emersed. 18 January 2015. Photo credit:  Allison J. Gong
Okenia rosacea, the Hopkins' Rose nudibranch, emersed. 18 January 2015.
© Allison J. Gong
Okenia rosacea, immersed. 18 January 2015. Photo credit:  Allison J. Gong
Okenia rosacea, immersed. 18 January 2015.
© Allison J. Gong

Only when the animal is immersed can you see that it is a slug and not a pink anemone such as Epiactis prolifera, which I’ve seen in the exact shade of pink. But anemones don’t crawl around quite like this:

Whenever I see O. rosacea I automatically look for its prey, the pink bryozoan Eurystomella bilabiata. Lo and behold, I found it! The bryozoan itself is also pretty.

The bryozoan Eurystomella bilabiata, preferred prey of the nudibranch Okenia rosacea. 18 January 2015.  Photo credit:  Allison J. Gong
The bryozoan Eurystomella bilabiata, preferred prey of the nudibranch Okenia rosacea. 18 January 2015.
© Allison J. Gong

Can you distinguish between the coralline algae and the pink bryozoan in the photo? Is it shape or color that gives it away? If you had to explain the difference in appearance between these two pink organisms to a blind person, how would you do it?

This past Tuesday and Wednesday afternoon I took my marine biology students to the rocky intertidal at Natural Bridges State Beach. We completely lucked out with the weather; the storm system that brought some of the rain that we desperately need had cleared out, leaving calm, clear seas and little wind. Perfect weather for taking students out in the field, in fact.

First of all, we didn't see any stars. Not that I was looking for them, particularly, but I was keeping an eye out for them and at this time last year I would have seen many Pisaster ochraceus hanging out in the pools and on the rocks. Here are a couple of pictures I took at Natural Bridges in years past:

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The stars, when present, are prominent residents of the mid-intertidal zone, where they feed on mussels. But now, alas, there don't seem to be any. They WILL come back, and it will be interesting to monitor their population recovery.

I enjoy taking students in the field because many of them have never been there before, and it's always fun looking at a familiar scene with fresh eyes. When everything is new, it is very easy to be excited and enthusiastic, which these students are.

We saw, among other things:

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Fish! The fish on the right was about 15 cm long. I think it's a woolly sculpin (Clinocottus analis), but IDing sculpins in the field is pretty tricky.
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This fish was much smaller, only about 10 cm long. It could be a fluffy sculpin (Oligocottus snyderi), or it could be a smaller woolly.
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This is an encrusting sponge, Haliclona sp. I've seen it in shades of rosy pink, too. The large holes are oscula, the sponge's excurrent openings. And that's a big gooseneck barnacle (Pollicipes polymerus) hanging down from the top of the picture.
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An assortment of intertidal critters sharing space on a rock. How many chitons can you spot?  How many barnacles?  How many limpets?
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This is one of my favorite intertidal animals, the owl limpet (Lottia gigantea). These large limpets are farmers. They keep an area clear of settlers by grazing at high tide. You can see the marks left by this individual's radula. The limpets also manage their farms, letting the algal film grow on one section while feeding on another.
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I love macro shots like this! The green tufty stuff is Cladophora columbiana, a filamentous green alga. Isn't it a vibrant green color? To give you an idea of how fine the Cladophora filaments are, that snail in the background is about the size of a quarter.
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And last, a gratuitous anemone shot. Ahhh, Anthopleura xanthogrammica, what a photogenic creature!

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