The annual Snapshot Cal Coast period is scheduled to coincide with the best midsummer low tides, to maximize opportunities for people to get out and blitz the intertidal. The whole idea of Snapshot Cal Coast is to document as much biodiversity as possible, to render a comprehensive account of what our coastal and nearshore biota look like at this moment in time. For someone like me, participating in the various bioblitzes that occur during Snapshot is a good excuse to get up early and play in some of my favorite intertidal sites.
We're in the high summer growing season now, and the algae are taking off. Pigeon Point has always been a great spot for seaweed diversity, and I anticipated having a lot much phycological fun when I went there last week. And, very happily, I was not disappointed. There were many animal finds as well, including some nudibranchs that I brought back to the Seymour Center, but the algae were definitely the stars of the show. So I thought I'd show off how beautiful and diverse they are.
The red algae
The vast majority of macroalgae at Pigeon Point are red algae, in the phylum Rhodophyta. Everywhere you look is a sea of rosy pinks, dark purples, and bright or brownish reds, punctuated now and then by a brilliant splash of green which is due to the surfgrass (not an alga!), Phyllospadix. The algae cover all surfaces. They drape into and drift with the water currents. They provide shelter and food for the animals of the intertidal. They make walking a treacherous undertaking--a large part of exploring the intertidal safely is knowing which algae will support your weight and which will dump you on your butt without a moment's hesitation.
At first look, the eye is bombarded with a confounding mélange of reds, dark greens, pinks, and purples. Knowing that they are all in the Rhodophyta doesn't help you make sense of what you are seeing. As usual, what helps is an ability to flip between what I call 'forest' and 'tree' observing: you can spend some time zeroing in on individual specimens and learning or remembering their names, but every once in a while you need to step back and take note of the larger environment where and with whom these species live.
Here's a small forest view to study. How many different red algae can you see?
It's kind of a trick question. A knowledgeable person can probably pick out seven or eight different species. I can distinguish six but can identify only five with any real certainty.
Here's the same photo, with some of the algae labeled for identification:
Species A: Prionitis lanceolata
Species B: Erythrophyllum delesserioides (my favorite alga!)
Species C: either Cryptopleura or Callophyllis
Species D: Neogastroclonium subarticulatum
Species E: Mazzaella splendens
Just because it's my favorite, and is undeniably beautiful, here's another photo of Erythrophyllum:
To give you some idea of the color and morphological variety in the reds, here's a quartet:
Some of the red algae are epiphytic, living on other algae or plants. Epiphytes are not parasitic and obtain their nutrients from the surrounding water. Although they do not drain nutrients from the alga or plant on which they live, epiphytic algae can occur so densely that they shade their host and deprive it of sunlight. In the intertidal, algae in the genus Microcladia grow as epiphytes. I've seen them most often on other reds, but they'll also live on some of the browns. A while back I wrote about how Microcladia closely resembles another red alga, Plocamium, and how one of the ways to tell them apart is to examine the habitat of each. Microcladia is an epiphyte, and Plocamium grows attached to rocks.
This is Microcladia:
You can see the morphology of M. coulteri a little better here, where it is an epiphyte on host with a smoother texture:
The coralline algae are a subset of the red algae. They have a different texture from the other reds, because they deposit calcium carbonate within their cell walls. Corallines can grow as encrusting sheets over surfaces, or have upright branching forms. They are often epizoic (living on animals) or epiphytic.
The brown algae
The brown algae (Phylum Ochrophyta) are not as diverse as the reds, but can be locally abundant. The browns come into their own in the subtidal, where they form the physical structure of California's famous kelp forests. Even in the intertidal they can be among the most conspicuous of the algal flora.
Egregia menziesii, the so-called feather boa kelp, is very common on our coast. It has tough, strap-like stipes that can be 3-4 meters long and a large conical holdfast, so it is pretty conspicuous. Egregia is the most desiccation-tolerant of the kelps around here; it grows as high as the mid-intertidal. The specimen in the photo below looks a little ragged at the ends, which makes me think it might be a holdover from last year.
I've seen Egregia at every rocky intertidal site so far. Other brown algae are more particular about where they live. Dictyoneurum californicum, for example, is a brown alga that lives only in areas that get a lot of water movement. It is seasonally abundant at Pigeon Point, where it is a low intertidal resident, but I don't see it at more sheltered locations such as Davenport or Natural Bridges. This year D. californicum is at Pigeon Point, although not in large patches as it was a few years ago. As the blades mature, they develop a split in the basal region just distal to the short stipe. The blades themselves feel crunchy and brittle.
All that said, the most remarkable brown alga at Pigeon Point has got to be Postelsia palmaeformis, the sea palm.
Postelsia is restricted to the most exposed rocky outcrops, where they bear the full force of the bashing waves as the tide rises and falls. They stick up defiantly above the surrounding topography, as if daring the waves to do their worst.
Sea palms grow to a height of about half a meter, and are usually the tallest things where they live. They typically occur in small clusters. They do resemble miniature palm trees, don't they? It's the thick, very flexible stipe that allows them to live where they do. When the waves come crashing down, the stipe simply bends with the force of the water, and then pops back up after the wave recedes. This hardiness doesn't make the thalli invincible, though. After winter storms blow through, you can often see Postelsia washed up on the beach.
You might think that Postelsia gets ripped off rocks by strong waves, but you'd be wrong. The holdfast for these algae is surprisingly tough and good at doing its job. When you see Postelsia stranded on the beach, you'll usually find that it wasn't the holdfast that gave way--most likely the rock or mussel it was attached to will have been torn off along with the sea palm. That's pretty impressive! Of course, any sea palm washed up on the beach is a dead sea palm, so in that sense it doesn't matter whether it was the alga or the substrate that failed. But given the forces that these algae withstand on a daily basis, it's remarkable how well they manage to hang on in the high energy environment where they thrive.
Algae don't get a lot of love, even among marine biologists. If I think there are not many people who study the invertebrates, there are even fewer who study seaweeds. Some organisms have an easier time attracting the attention of human beings, and among macroscopic organisms the invertebrates and algae are probably tied for the bottom ranking. It amazes me that visitors to the seashore can look over a place like Pigeon Point and not see anything. I suppose it's a matter of getting lost in the forest and forgetting that it is made up of trees, or not even recognizing that it is a forest. In the intertidal the 'trees' are at foot level so it does take some work to figure out what's going on. Like most worthy endeavors, though, the effort is well rewarded.
Professor Emeritus John Pearse has been monitoring intertidal areas in the Monterey Bay region since the early 1970s. Here on the north end of Monterey Bay, he set up two research sites: Opal Cliffs in 1972 and Soquel Point in 1970. These sites are separated by about 975 meters (3200 feet) as the gull flies. My understanding is that the original motivation for studying these sites was to compare the biota at Soquel Point, which had a sewage outfall at the time, with that at Opal Cliffs, which did not. The sewer discharge was relocated in 1976, and the project has now morphed into a study of long-term recovery at the two sites. In the decades since, John has led students, former students, and community members to conduct Critter Counts at these sites during one of the mid-year low tides. Soquel Point is visited on the first day, and Opal Cliffs is visited the following day. When John founded the LiMPETS rocky intertidal monitoring program for teachers and students in the 1990s, the Soquel Point and Opal Cliffs locations were incorporated into the LiMPETS regime.
I have participated in the annual Critter Counts off and on through the years--around here, one takes any chance one gets to venture into the intertidal with John Pearse! I usually have my own plans for this series of low tides, but try to make at least one of the Critter Count mornings. This year (2019) the first 16 days of June have been designated the official time frame for Snapshot Cal Coast, giving marine biologists and marine aficionados an excuse to go to the ocean and make observations for iNaturalist. I had set myself the goal of submitting observations for every day of Snapshot Cal Coast, knowing that every day this week would be devoted to morning low tides. That's the easy part. Next week, when we lose the minus tides, I'll do other things, like look at plankton or photograph seabirds. My plans for this week included a trip to Franklin Point on Wednesday and doing the Critter Count at Opal Cliffs on Thursday. John asked me if I could also do the Wednesday Critter Count. As I alluded above, I'm not going to say "No" to an invitation like that! So I didn't make it out to Franklin Point to document the staurozoans for Snapshot Cal Coast, but that's okay. Some plans are meant to be changed.
Day 1- Soquel Point
Both the Soquel Point and Opal Cliffs sites are flat benches with little vertical topography. The benches are separated by channels that retain water as the tide recedes. The Soquel Point site has deeper channels that make the benches more like islands than connected platforms.
The benches are pretty easy to get around on, as long as you remember that surfgrass (Phyllospadix spp.) is treacherous stuff. The long leaves are slippery and tend to cover pitfalls like unexpected deepish holes. The difficulty at this site is that it takes very little rise in the tide for water in the channels to get deep. You can be working along for a while, then get up to leave and realize that you're surrounded by water. Keeping that caveat in mind, we worked fast.
For the Critter Count we keep tabs on only a subset of the organisms in the intertidal. The quadrat defines our sample; we put it down at randomly determined coordinates within a permanent study area. Some animals, such as anemones, turban snails, and hermit crabs, are counted individually. For other organisms (surfgrass, algae, Phragmatopoma) we count how many of the 25 small squares they appear in. Some quadrats are pretty easy and take little time; others, such as ones that are placed over channels or pools, are more difficult and take much longer.
Because of the rising tide I didn't have a lot of time to look around and take photos of the critters we were counting. Linda and I were worried about finishing our quadrats before the channels got deep enough to flood our boots. But here are two of the things that caught my eye:
Day 2 - Opal Cliffs
The next day we met a half hour later and a few blocks down the road. The Opal Cliffs site is a popular spot with surfers: If you've ever heard of the surf spot Pleasure Point or seen the movie Chasing Mavericks, you know about this location. As far as the intertidal goes, it's an easy site to study. The channels aren't as deep as those at Soquel Point so we could work at a more leisurely pace. As the rest of the group hauled up all the gear and left to get on with their day, I stayed behind to take pictures for my iNaturalist observations. The sky was overcast, making for good picture-taking conditions. I'll just add a gallery of photos to share with you.
There is one critter that deserve more attention here, because I'd never seen one in the intertidal before. Two of the guys finished their quadrats early and started flipping over rocks to look for an octopus. To my knowledge they didn't find any octopuses, but they did find a bizarre fish. At first it didn't look like much:
Hannah, the LiMPETS coordinator for Monterey and Santa Cruz Counties, recognized the fish right away and grabbed it by the body. She held it up so we could see the ventral surface.
This is a plainfin midshipman. These are nearshore fish found in the Eastern Pacific from Alaska to southern Baja. Clearly, I need to spend more time flipping over big rocks! The midshipman is a noctural fish, resting in the sand during the day and venturing out to feed at night. Like many nocturnal animals, it is bioluminescent--those white dots on the fish's belly in the photo above are photophores. Midshipmen are heavily decorated with photophores all over the body. This bioluminescence is used both for predator avoidance and mate choice.
The lives of plainfin midshipmen and human beings intersect in the wee hours of the morning. During breeding season these fish sing or grunt. They breed in intertidal areas, where females lay eggs in nests that are subsequently guarded by males. Both sexes make noise, but it's the breeding males that are the noisiest. They grunt and growl at each other when fighting for territory, but hum when courting females. Females typically grunt only when in conflict with others. People who live in houseboats on the water in Sausalito have reported strange sounds emanating from the water beneath them, only to learn that what they hear are the love and fight songs of fish!
I've always been a fan of the intertidal fishes. They seem to have a lot of personality. Plus, any aquatic animal that lives where the water could dry up once or twice a day deserves my admiration. Of course, all of the invertebrates also fall into this category, which may explain why I find them so fascinating.
After we admired the midshipman's photophores and impressive teeth, we put it back in the sand and replaced the rock on top of it. It was probably happy to get back to snoozing away the next few hours before the tide returned. I don't know how I never realized the midshipmen were in the intertidal. I think I just assumed that they were in deeper water. Now that I know where to find them, I will spend more time flipping over rocks. And who knows, maybe I'll even find an octopus!