The marine macroalgae, or seaweeds, are classified into three phyla: Ochrophyta (brown algae), Rhodophyta (red algae), and Chlorophyta (green algae). Along the California coast the reds are the most diverse, with several hundred species. The browns have the largest thalli (the phycologists' term for the bodies of algae), including the very large subtidal kelps as well as the smaller intertidal rockweeds. The green algae are small in both thallus size/complexity and species diversity; many of the greens are filamentous and look like nothing more than slime growing on rocks or other surfaces.
On the other hand, what appears to be simple at first glance can turn out to be delightfully complicated and puzzling upon closer examination. Take, for example, the two species of green algae in the genus Codium that occur intertidally in northern California: Codium setchellii and C. fragile. Codium setchellii is a native species here. It grows as a thick rugose mat over rocks in the mid-intertidal. Its color is a very deep olive green, but when dry it looks almost black.
Codium setchellii has a smooth texture and feels like very thick velvet. It grows on vertical faces of rocks, rarely on exposed horizontal surfaces--at least, I've not often seen it on top of a rock. Patches of C. setchellii are usually about the size of my outstretched hand, although some can be a little larger than that. When you see C. setchellii in the field, it's hard to imagine what type of structure would result in a thallus like this. To figure out what's going on, you need to look at small pieces under a microscope. It's this level of observation that reveals the filamentous nature of C. setchellii.
Phycologists have a few tricks for observing the internal structure of algae. The firm-bodied algae can be examined via cross-section, which can be more or less difficult to make depending on the species. Many simpler thalli, however, can be examined by making a squash, which is exactly what it sounds like: You take a piece of the alga, place it in a drop of water in a slide, and squash it with a cover slip.
A squash of C. setchellii revealed this mishmash of filaments:
This particular squash shows the utricles, which are the pigmented ends of the filaments. It didn't really help me understand how the filaments are organized within the thallus, though. I even tried making a cross-section of the little piece of C. setchellii I have, but it turned to mush. I did at least get one squash that showed the filaments to be arranged in approximately parallel fashion at the outer edge of the thallus.
So, seeing the internal structure of Codium setchellii allows me to understand how its closely packed filaments produce the velvety cushion of the thallus that I see in the field. The way that the filaments are aligned allows them to be tightly packed together, resulting in a cushion that is surprisingly firm rather than squishy.
The second species of Codium that we see in northern California is C. fragile, commonly called 'dead man's fingers'. It is a non-native species here, originating in the western Pacific near Japan, and has spread into the Atlantic. In California it has a patchy distribution and, in my experience at least, isn't as common as C. setchellii. I have never seen the two species together at the same site, but according to iNaturalist they do co-occur in some locations.
Like its congeneric species, C. fragile is a dark greenish color and lives in the mid- to low-intertidal. But otherwise it looks entirely different. The thallus morphology must be what gave rise to the common name. I remember learning years ago about a seaweed called 'dead man's fingers' and being disappointed when I saw it for the first time. It didn't look like dead man's anything!
This thallus resembles a clump of approximately dichotomously branching tubes. It is spongy in texture and is often colonized by bits of a filamentous red alga.
In this case, the red alga (Ceramium sp.) is in turn colonized by the benthic diatom Isthmia nervosa:
You might expect Codium fragile, having a tubular morphology, to be more amenable to being examined in cross-section. I can tell you that that isn't the case. It's easy enough to make the first transverse slice of one of those 'fingers', but the second slice, even made with a brand new razor or scalpel blade, results in a pile of mush. I made and looked at several such piles, hoping that at least one would show an approximation of the cross-sectional anatomy of this thallus. The best I could get was this:
At least it shows the radiating arrangement of the filaments. I think this is really interesting. The utricles (pigmented tips of the filaments) are a bit thicker than the unpigmented section of the filaments that make up the interior of the cylinder, but there's still space between them at their distal tips. It is this arrangement that gives Codium fragile a squishiness that C. setchellii lacks.
So there you have it. One genus, two species with radically different gross morphology but similar internal morphology. They're made of the same types of cells, at least. Like I said, I've not seen them in the same place in the field, but here in my blog you can see them side by side.
Monterey Bay is shaped like a backwards letter 'C', with Santa Cruz on the north end and the Monterey Peninsula on the south end. The top of the 'C' is comparatively smooth, while the bottom is punctuated by the Monterey Peninsula, which juts north from the city of Monterey. The most striking geologic feature is the Monterey Submarine Canyon, but of course you can't see that from land. It is crazy to realize that the canyon starts right off the jetty at Moss Landing. It is this proximity to deep water that makes the Monterey Bay Aquarium Research Institute (MBARI) so ideally situated.
Separated by 40.2 km (= approximately 25 statute miles) as measured harbor to harbor, Santa Cruz and Monterey represent both the same and slightly different marine habitats. On a large scale they are both part of the California Current system, strongly affected and biologically defined by seasonal upwelling in the spring and summer months. On a finer scale they differ in a few ways, primarily geologic. The rock on the Santa Cruz end of the bay is a soft sand- or mudstone, and at sites like Natural Bridges can be easily eroded; you can scratch it with your thumbnail, and falling on it might give you a bruise but probably won't beat you up more than that. The rock of the Monterey Peninsula is much less forgiving: granite with large quartz crystals. Falling on that stuff can leave you with bruises and a bad case of rock rash; I usually end up bleeding from at least one laceration when I'm in the intertidal there.
The difference in rock type between the north and south ends of Monterey Bay also manifests in the tidepools themselves. The soft mud stone of the Santa Cruz erodes into small particles, which form nice soft sandy beaches. Small particles also remain suspended in water more so than larger ones, which affects water clarity. Larger and heavier particles, on the other hand, sink out of the water, so that the water column itself tends to be less murky. Clear water has some marked advantages over murky water. For example, light transmission is directly proportional to water clarity. Thus, all other factors being equal, photosynthetic organisms such as algae have access to more light, in waters above large-grained sand than those above finer sediments.
That being said, it is not always the case that clearer water is better. Remember Phragmatopoma californica, one of the worms I wrote about recently? They build tubes out of sand grains. However, it turns out that they are particular about the sand grains they use. If you were to examine a Phragmatopoma tube under a dissecting scope you'd see that all of the sand grains are the same size. Just how they select and sort the sand grains isn't understood, but somehow they manage to choose the particles they want and cement them together underwater. Phragmatopoma is one of the most conspicuous animals at Natural Bridges on the north side of Monterey Bay, forming large mounds of hundreds of individuals, yet very few live on the Monterey Peninsula. There are likely several reasons for this, but part of the explanation is that the sand grains are too big to be used in the worms' tubes.
I live in Santa Cruz, on the north end of the bay, and most of my intertidal excursions these days are to locations in Santa Cruz and north along the coast. I haven't spent nearly as much time as I'd like to in the tidepools on the Monterey Peninsula and locations further south. It's tough getting to a site an hour away, when the low tide is at dawn. And with my post-concussion syndrome I don't yet feel comfortable driving myself that far away and back. Fortunately for me, I am currently mentoring a student working on an independent study project, and she was willing to drive down to Asilomar last weekend. So I tagged along with her.
Asilomar State Reserve is one of California's no-take marine protected areas (MPAs), where people can look and take pictures but are not allowed to remove anything, dead or alive. It is a glorious site. The water is clear and blue, and the biota is both similar to and different from that on the north side of the bay. I want to highlight some of the organisms that I see there, that are less common here on the north side.
Abalone (Haliotis sp.) are not unheard of here. In fact, there is a black ab (H. cracherodii) at Natural Bridges that I've been keeping an eye on since 2015, tucked into a crevice and generally not visible except on a minus tide. And further north at Pigeon Point I have seen red abalone (H. rufescens), both living and empty shells. But I've never seen as many black abs as I saw at Asilomar. Standing in a depression about as big as my kitchen table, well above the water level, I easily counted at least 20 black abs. Some of them were as big as my hand. How many can you see in the photo above?
Abalone are large herbivorous snails. They feed on macroalgae, both reds and browns. If they venture from the safety of their nooks and crannies they can chase (at a snail's pace) down algae, but then they are vulnerable to predators such as cabezons and sea otters. Abs that live in crevices, like these, have to rely on drift algae to come to them; they don't have the luxury of choosing what to eat. It's the age-old compromise between safety and food, one of the driving forces in foraging behavior.
While we have four species of anemones in the genus Anthopleura at the Santa Cruz end of the bay, as well as other anemones such as Epiactis, we don't have any in the genus Urticina--not intertidally, at least. I have seen Urticina anemones at Carmel, and last weekend saw what I think was U. coriacea. It was in a pool, and partially obscured by sand and its own pharynx.
It's own pharynx, you ask? Yes! Anemones are cnidarians, and as such have a two-way gut. This means that food is ingested and wastes are expelled via a single opening, which for politeness' sake we call a mouth even though it also functions as an anus. Sometimes, when an anemone is expelling wastes, it also turns out the top part of its pharynx. This is a temporary condition, and the pharynx will be returned to normal soon. The anemone in the picture above appears to be in the process of spitting out something fairly large and undigestible.
Here's another example of an anemone eating a big meal, this time of mussels.
What do you think this thing (below) is?
I had at first misidentified these as something else, but have since been told that they are the tubes of another of those strange terebellid polychaete worms. This one is Pista elongata. As with many terebellids, P. elongata lives in a tube, the opening end of which is elaborated into a sort of basket. They reportedly range from British Columbia to San Diego. I think I've seen them at Carmel Point, but not at Point Piños, which I've visited more often. And I'm positive I've never seen it at Natural Bridges.
At Asilomar I saw some large clusters of P. elongata in the low intertidal. They are not clonal, to my knowledge, so these aggregations would form by gregarious settlement of competent larvae when they return to shore.
One solitary ascidian that I saw at Asilomar is Clavelina huntsmani, the appropriately called lightbulb tunicate:
For people too young to remember what an incandescent light bulb looks like, they were made of clear or frosted glass. Inside the glass bulb were tungsten filaments, through which electricity flowed; the filaments heated up enough to emit light. In Clavelina, the two pink structures running down the length of each zooid resemble the filaments of an incandescent light bulb, but are in fact parts of the pharyngeal basket, the structure used for filter feeding.
We have neither Pista nor Clavelina in Santa Cruz--at least, I've never seen them. They remind me that although Santa Cruz and Monterey are part of the same ecosystem, they do not represent the same microhabitat. I'm pretty familiar with the intertidal floral and fauna in Santa Cruz, but I absolutely love exploring the intertidal along the Monterey Peninsula. There's something exciting about spending time a place I don't know as well as the back of my hand. I hope that as my brain continues to heal I'll eventually regain the stamina to travel so far for a low tide.
Today is the first day of the week of low tides dedicated to Snapshot Cal Coast, a statewide citizen science project headed in my area by the California Academy of Sciences. This week groups and individuals will be making photographing the organisms they see in the ocean or along the coast, and uploading observations to iNaturalist. Participants will include both scientists and non-scientists, making the week-long event one of the biggest citizen science projects that I regularly take part in. Next Monday I'll be taking a group of Seymour Center volunteers and staff up to Davenport to conduct a Bioblitz. The other days I'll be out on my own, or with 1 or 2 people.
This morning the low tide was very early (-1.3 feet at 05:09), so I stayed close to home and went to Natural Bridges. The tide was low but the swell was big and I wasn't able to get down to the low spots I could normally reach with this kind of tide. However, this meant that I could spend more time in the low-mid-intertidal, where there is a lot of biodiversity to document.
Today I want to write about polychaete worms. These are the segmented marine worms in the Phylum Annelida, which also includes earthworms and leeches.
Worm #1: Phragmatopoma californica
One of the most conspicuous inhabitants of this zone is the tube-dwelling polychaete worm, Phragmatopoma californica. This worm has a couple of common names: honeycomb worm, which refers to the mounds of tubes they build; and sandcastle worm, for the fact that the tubes are built of cemented sand grains. In effect, these worms are tiny masons!
Each of the tubes is inhabited by a single worm. Mounds form because competent Phragmatopoma larvae, looking for a place to settle out and live permanently, are attracted to the tubes of existing adults. This phenomenon is called gregarious settlement. Once settled and metamorphosed, juvenile worms build their tubes by selecting sand grains and cementing them together around a lining of chitin-like material. How they do it, underwater, nobody knows. And these tubes are tough! The worm inside is skinny, and a humongous one would be all of 4 cm long, but it takes a lot of force to pry apart those sand grains. The openings to the tubes are 5-10 mm in diameter. Each worm can close off its tube with a circular-ish disc of stiff, fused chaetae called an operculum; this protects the worm from both predators and desiccation.
When the tide is out the worms withdraw into their tubes and clap the operculum down. They wait for the water to return. Phragmatopoma is a filter feeder; like most of the tube-dwelling polychaetes these worms use a crown of ciliated tentacles to create water currents that draw food particles to the mouth. When the tide is in the worms pull down the operculum and extend their feeding tentacles into the water. In the field, this is the most you can see of the worm's body.
Worm #2: Serpula columbiana
Many polychaetes live in tubes, and tubes can be made of a variety of materials. Phragmatopoma californica builds tubes out of sand grains. Another worm that I saw today, Serpula columbiana, builds tubes out of CaCO3 precipitated from seawater. Like other animals that build calcareous skeletons, S. columbiana may in the future have difficulty precipitating CaCO3 in an increasingly acidic ocean. Tubes of Serpula worms are white when new and soon become fouled with algal growth, and tend to wander over the substrate. The best photo I could take this morning is a little blurry but you can see the general morphology of the tubes.
These worms are incredibly shy, and react to any perceived threat by pulling into their tubes. Their tentacles have tiny eyespots that can detect changes in light, so passing a hand over them can cause them to withdraw. Fortunately I was able to sneak up on one lazy worm in a pool, and grab a shot of its 'head' region. Worms that live in tubes are poorly cephalized, with none of the structures that we generally associate with a head. Serpula columbiana's 'head' looks like this:
The tentacles of S. columbiana are morphologically complex compared to those of Phragmatopoma. Serpula's tentacles are pinnate, or feather-shaped, and in cross-section look like a V. Cilia on the side branches of the tentacle create the feeding current, and food particles are transported by other cilia down the trough of the V to the mouth.
See that long, trumpet-shaped structure? That's the worm's operculum!
Worm #3: Unidentified cirratulid
Unlike Serpula and Phragmatopoma, worms of the Family Cirratulidae don't live in tubes. Instead, they live with most of the body hidden in crevices, and extend tentacles to feed.
As you can imagine, it is extremely difficult to identify a worm when all you can see of it are its tentacles; with the rest of the body hidden in a crevice, there are no visible characteristics to use to distinguish species. Cirratulids use their tentacles to feed, but in a way that is entirely unlike how Phragmatopoma and Serpula use theirs. Instead of feeding on particles suspended in the water, cirratulids are deposit feeders. They sweep their tentacles across the surface and collect organic deposits. Sticky mucus on the tentacles picks up organic matter, and cilia on the tentacles sweep the organic matter to the worm's mouth.
Don't believe me? Watch this!
It doesn't matter if the surrounding substrate is sand or rock. The cirratulid's sticky tentacles are very effective at gathering organic muck.
Worm #4: Flabesymbios commensalis
This worm remains an enigma. There doesn't seem to be much known about its biology. I have seen them twice, both times on the body of purple urchins (Strongylocentrotus purpuratus), and although the genus name has changed twice since the first time, I'm pretty sure it's the same worm. As the species epithet commensalis implies, this worm is a commensal on sea urchins. This means that it neither harms nor benefits its echinoderm host. Similar to the worm I've seen on bat stars, F. commensalis presumably cruises over the urchin's body and feeds on detritus or scraps of kelp that the urchin grabs.
When I took the photo in a tide pool this morning I didn't see the worm. It wasn't until I downloaded the pictures from the camera onto my computer that I saw it. See how well it blends in with the urchin's color?
Here's a tighter crop of that photo:
For many polychaete worms, another animal's body seems to be the ideal habitat. And for some reason, echinoderms are likely hosts for such commensal worms. I've written about the bat star worms, here is the urchin worm, and there's also a scale worm that I've seen crawling around on the body of a sea cucumber. What is it about echinoderms that makes them habitat for worms? Or is this type of commensalism also common, but less observed, between polychaetes and other non-echinoderm invertebrates? I don't know the answer to either of those questions, but am very intrigued.
This weekend a subset of my students and I spent a day at the Fort Ord Natural Reserve (FONR) to participate in the 2018 spring Bioblitz. We were supposed to visit FONR for a class field trip in early March to do some vegetation studies, but that trip was rained out. Today's visit was sort of a make-up for that missed lab; because it's a Saturday I couldn't compel the students to attend, but I offered a little extra-credit for those who did. It just so happened that Joe Miller, the field manager at FONR, had organized a Bioblitz for another group of students, and he welcomed my Ecology class as well.
Located adjacent to the city of Marina in Monterey County, FONR is one of five natural reserves administered by the campus of UC Santa Cruz. The other four are the Campus Reserve (on the main campus of UCSC), Younger Lagoon Reserve (on UCSC's Coastal Science Campus), Año Nuevo Natural Reserve (up the coast in San Mateo County), and Landels-Hill Big Creek Reserve (along the Big Sur coast). FONR occupies some 600 acres of a former military base that was closed in 1994. The reserve opened in 1996. As with all the other UC natural reserves, FONR exists to provide students, teachers, and researchers with natural lands to be used as outdoor classrooms and laboratories. Field courses at UC Santa Cruz and CSU Monterey Bay make extensive use of FONR, and students carry out independent studies and internships there.
After all of the participants arrived at the Reserve, Joe described the activities he had planned for the day. He told us that we could wander around the Reserve on our own if we wanted, but there were several hikes we could choose to join:
One to where some people were finishing up the day's bird banding activities
One to collect samples of environmental DNA
One to ID various tracks in the sand
One to the different habitats and vegetation types
One to check out some pitfall traps for small rodents and reptiles
Because my knowledge of the local flora is sorely lacking, I went on the plant hike with Joe. Many of the spring wildflowers had either finished or were finishing up their yearly bloom. The poison oak (Toxicodendron diversilobum) is looking amazing this year; I think it has been able to take advantage of two consecutive wet seasons with a decent amount of rain. There were many poison oak plantlets scattered around all over the place, and the established bushes are lush and green. There is no way I didn't come into contact with the stuff at least once on this hike, so today is going to be the true test of whether or not I am allergic to it.
Much of the terrain at FONR is a maritime chaparral. The soil is extremely sandy (Pleistocene sand dunes, Joe says) with a poor nutrient load and water content. It's not a desert, because we do get a fair amount of precipitation along the Monterey Bay, but the plants have adapted to thrive with low soil moisture levels. It's also often very windy, and there are no trees. Even the coast live oaks (Quercus agrifolia), which can be magnificently massive and meandering, are stunted here. Much of the foliage is low-growing perennial shrubs or annual plants.
Joe led us through the habitats of the Reserve, mostly on trails but also along narrow-to-nonexistent tracks that we called Poison Oak Lane, Rattlesnake Drive, and Tick Alley. And yes, we did see a rattlesnake! My husband spotted it, right about where he was going to put his foot. It wasn't a big snake, maybe half a meter long, and was sunning itself in a narrow opening between manzanita bushes. I didn't stop to take a picture because there wasn't a good space to do so, and I wanted to let other hikers pass the snake quickly. The snake didn't seem to react to us, but it's always a good idea to leave them alone.
Just beyond where we saw the rattler, Joe had found a pair of southern alligator lizards (Elgaria multicarinata) mating. When Joe picked them up the male had grabbed the female with a bite behind her head; he does this to keep her from running away, and it also shows his strength and suitability as a father for the female's offspring. The lizards didn't like being interrupted in copulo, so to speak, and the male released the female and escaped back to the ground, leaving his lady love behind in Joe's hand. Hopefully they were able to find each other again once they were both let go.
To me, the picture above exemplifies what a Bioblitz is all about. We have two people examining a natural phenomenon, and one of them is taking a picture that he will presumably upload to iNaturalist. People learn a lot when they participate in a Bioblitz--they usually see things they've never paid attention to before, and when their observations are ID'd or corroborated by the community of iNat experts, they get to put a name to the thing they saw. True, it's a better learning experience to sit down with a specimen, hand lens, and book to figure out what an organism is, but most people don't have either the inclination or the luxury of time and the necessary books. And while I'd rather have people look at the real thing with their eyes instead of their phones, getting people to go outdoors and pay any attention at all to their surroundings is a minor victory. I find Bioblitzes to be a little unsettling sometimes. My preferred method for observation is to examine fewer things in greater depth; this is what my graduate advisor Todd Newberry referred to as "varsity" observations. I don't think a Bioblitz has any place in varsity studies, because of its very raison d'être--to record as many observations as possible--means to some degree that instead of taking a deep look you have to glance-and-go. Still, it does have its place in natural history, and I value it as a way to get more people involved in science.
I was on the plant hike, so many of the organisms I photographed and uploaded to iNat are new to me. Some are California endemics and all have adapted to survive in the difficult conditions of a maritime chaparral.
And I did see one of the California native thistles. Invasive thistles are such a problem that the knee-jerk response is to stomp on them or yank them out of the ground. This one, for which I'm still waiting on an ID confirmation, is silvery and sort of looks like cobwebs. Joe said that its blossom is a bright pink.
And one of my newish old favorite wildflowers, Castilleja exserta, was there. The purple owl's clover occurs throughout California; in 2017 I saw a lot of it on my wildflower excursion to the southern part of the state. It varies in color from purple to pink to white and thus has multiple common names.
We also saw a lot of the peak rushrose, Helianthemum scoparium. It is a California native species that does well in dry, sandy areas, such as throughout most of Fort Ord.
While I was leaning down to photograph this plant, one of the Reserve volunteers pointed out a much paler version nearby. He told me that most of the time the peak rushrose has brilliant yellow flowers, but there are always a few that have this much more delicate color.
And speaking of yellow, I discovered another new-to-me organism! What at first glance looked like a blotch of spray paint on a tree trunk turned out to be something much more interesting--a gold dust lichen in the genus Chrysothrix.
The lichen book1 that I have describes two species of Chrysothrix, both of which can be found in coastal regions of California. The species have some overlap in habitat, with C. granulosa usually living on bark and occasionally on wood or rock, while C. xanthina can regularly be found on bark, wood, and rock. Nor is color by itself an entirely useful characteristic: C. granulosa is described as brilliant yellow, and C. xanthina can be brilliant yellow, yellow-green, or yellow-orange. There are certain tests that would be able to distinguish between the species, but field ID when the lichen is 'brilliant yellow' remains problematic. So while I'd guess that this specimen is Chrysothrix granulosa (based on a combination of color, location, habitat, and good old-fashioned gut feeling) I can't be at all certain.
The discussion of lichens brings us around to the animals. Did you know that fungi are more closely related to animals than they are to plants? Well they are, despite being included in more botany than zoology courses. And of course we did see animals on our plant hike. Hawks and turkey vultures soared overhead, song birds and hummingbirds flitted among the trees and shrubs, alligator lizards mated, and there was that one rattlesnake, which even the people on the herps walk didn't get to see. As we hiked through the various plant communities in the Reserve, Joe occasionally called out "If you see a horned lizard, catch it!" A woman in our group, Yvonne, managed to do so, despite being loaded down with a backpack and a camera. She pounced on it and held it up for us to photograph.
Cute little thing, isn't it?
The last critter we saw as we were walking back to the gate after lunch was a juvenile gopher snake (Pituophis catenifer). By the time I got there the snake was resting in the road. It was a very pretty snake. I wanted to take it home and release it into my yard, where there are enough gophers to feed an entire family of snakes, but alas, collecting is not allowed at the Reserve. I do wish that a gopher snake would move into my yard, though.
It is now about 24 hours since we got home. We did our tick checks and didn't find anything, thank goodness, then showered and scrubbed. There's no doubt that we were both exposed to poison oak; it is impossible NOT to be, this time of year. This is the real test for whether or not I am allergic to it. I haven't been so far, but there's a first time for everything and I will never say that I will never get it. My husband, who gets poison oak very easily and very badly, says it could take up to two days to be sure. I'm not itchy today. Tomorrow may be a different story, though.
1Sharnoff, S. 2014. A Field Guide to California Lichens, Yale University Press
About a year and a half ago I wrote about salmonids and beavers in the Lake Tahoe-Taylor Creek region, specifically about the non-native kokanee salmon (Oncorhynchus nerka) that were introduced into the region in the 1930s and 1940s as a game fish. Since then the kokanee has displaced the only salmonid native to the Tahoe basin, the Lahontan cutthroat trout (Oncorhynchus clarkii henshawi), to the point that the latter was thought to be extinct.
Fast forward several decades, and Professor Mary Peacock of the University of Nevada, Reno, has found some long-forgotten Lahontan cutthroats in tiny streams in eastern Nevada near the Utah border. This is Professor Peacock's story to tell, not mine, and you can read about it in this newspaper article. The article has a link to the actual scientific paper, published in an open-source avenue of the Royal Society. This truly is a resurrection story!
This week I celebrate the return of the early morning low tides! I was very much looking forward to this tide series, and even though I am in class on Tuesday, Thursday, and Friday mornings I wanted to go out on as many of the tides as possible. On Wednesday morning I went out to Natural Bridges to meet up with one of my students, Maddie, who is studying anemones for her independent research project. The tide wasn't particularly early at 07:08, but there was nobody out there. No surfers, even. The only person I saw out there was Maddie.
There are few things better than an overcast morning in the intertidal. Peaceful, calm, not windy, and uncrowded. I could feel the stress melting away as the only sounds I heard were the coming and going of the surf and the high-pitched 'cheeps' of the oystercatchers.
Natural Bridges is probably the intertidal site that I know the best. It's close to home, so access is easy. It is a state park and a marine protected area, so collecting of any sort is not allowed and the tidepools are about as undisturbed as can be, considering that it is heavily visited. And in the early morning the intertidal is just wonderful. Visiting there and having time to slow down and really pay attention is a real treat for me.
And perhaps the homecoming I felt this morning is due to the fact that just last week I gave a talk to the docents at Natural Bridges State Park. There's something about this particular group that inspires me and rekindles my interest in this special site.
It is now springtime, and the intertidal is in the full flush of reproduction. The algae are starting to regrow and hinting of the lush coverage that we'll see in the next few months.
There are several species in the genus Ulva, referred to as the sea lettuces. They come in a variety of morphs, but all are variations on the same theme: a thin sheet, two cell layers thick. Some Ulva species have blades that are large, while in other species the sheets are rolled into thin tubes or short tufts. Many of them look alike, making field ID problematic, so with few exceptions I simply call them all Ulva sp.
The other common green alga at Natural Bridges is one of the filamentous green, Cladophora columbiana. It has a short thallus, rising from the rock surface like a stout pincushion, which is what it feels like. It grows in little clumps among the mussels in the mid-intertidal.
Today I saw Cladophora with little periwinkle snails, an association that, in my experience, is unusual. The periwinkles are small, less than 10 mm from aperture to apex, and I tend to think of them as a high intertidal species. Cladophora can also occur in the high-mid intertidal but for some reason seeing them together with the periwinkles took me by surprise. There were many of the little snails crawling around in the mid zone, on bare rock or on other animals.
In fact, today was a good day to see lots of animal recruitment. Several areas of rock in the mid-intertidal that were recently devoid of animal life have been colonized by mussels or acorn barnacles.
Most of the individuals in this field of barnacles are Chthamalus dalli/fissus. Those are the small, light brown barnacles. The taller whitish barnacle near the center of the photo is Balanus glandula. But see all the teensy barnacles below and slightly to the left of the Balanus? Those are new recruits, 1-2 mm in diameter. If you click on the photo for a larger view, you can see that while most of the recruits are Chthamalus, there are a few Balanus in there as well. And notice that some of the recruits have landed on other barnacles. This is a smart decision for them. As I've described before, barnacles can't reproduce unless they have close neighbors of the same species. Settling on an established conspecific adult is one way to guarantee that a young barnacle will have potential mates when it grows up.
The largest barnacle in the intertidal around here is the pink barnacle, Tetraclita rubescens. It is fairly common at Natural Bridges, and quite conspicuous because of its size and pink color.
And take a look at this owl limpet! She's carrying a whole world on her back.
Speaking of owl limpets, their tendency to monopolize territories in the intertidal can strongly affect the makeup of the community. It's not just the barnacles that recruit to the intertidal in the spring; mussels do the same, and often quite spectacularly. The disappearance of predatory ochre stars (Pisaster ochraceus) due to sea star wasting syndrome (SSWS) allowed mussels to expand lower into the intertidal, where they would ordinarily be eaten. The ochre stars have been reappearing in the past few years, and hand-sized P. ochraceus are now very common at Natural Bridges. We would now expect predation to cause the lower edge of the mussel bed to retreat back up a bit.
Mussels cannot recruit to Lottia farms because the limpets routinely cruise around their territories and scrape off any newly settled larvae. Lottia farms occur in what would otherwise be prime real estate for mussels, except for the fact that the larvae landing there never get a chance to become established. However, even a big owl limpet doesn't live forever, and when one dies a whole swath of now-vacant area becomes available.
Those two bare patches in the photo above are former Lottia farms. I looked for the owl limpets and didn't find them. And note that band of young mussels running horizontally in the middle of the photo. They are young mussels, relatively clean of encrusting mussels or algae, but aren't new recruits. I'd guess that they've been there a few months. Whatever the age of the mussels, they are taking advantage of the space that used to be occupied and defended by an owl limpet. Or maybe two owl limpets, as that space would be a very large farm for a single limpet.
After two days of class taking me out of the intertidal, I get to spend the next two mornings back out there. I have some collecting to do!
Library of Congress I was completely unprepared for how astoundingly beautiful the Library of Congress is. From the outside it looks like another of the many federal buildings constructed in the Classical style. The interior, though, was spectacular.
The ceiling of the Great Hall is magnificent--take a look at this stained glass!
We joined a tour and the docent explained the significance of many of the architectural and artistic details she pointed out to us. She told us that when the building was designed in the 1890s, the intent was to portray the United States as a major player on the world stage, able to build in the Classical style as well as the Europeans did, while adding details that are distinctly American. For example, the mosaic floor of the great hall features a motif of an ear of corn, to represent a New World plant that isn't native to Europe.
And this painting, high up on a wall, represents Sport. It features baseball, that most American of sports! The corresponding painting on the opposite wall shows American football. And of course the athletes are naked, because that's how the ancient Greek athletes competed. Artistic nudity, either in painting or in sculpture, was not a problem in the 1890s. There were no prudes calling for fig leaves to be placed over statues' genitals, or for female nipples to be covered with pasties.
Our docent told us that the building's designers were all Americans, but that some of the actual artisans were brought over from Europe. Likewise, much of the stone came from quarries in the U.S. The marble for those columns with the fancy capitals, however, was mined near Siena, Italy. She wasn't sure if it was Cararra marble. I think the look is right for Cararra marble, though.
There a lot going on, visually, inside this building. It's exactly the kind of visual input that should have killed my brain right on the spot. However, because all of the elements conform to the theme of Classical Greek and Roman design, they fit together thematically. The net result is very pleasing to the eye. I would really like to return and go on a tour with a different docent, who would highlight other things for us to look at. The amount of symbolism and history in the building is fantastic. Every item and detail means something.
Our docent pointed out that there were no depictions of named women, anywhere in the Library of Congress. However, female figures were often used to portray broad themes such as wisdom, philosophy, culture, government, and the like. There is one mosaic of the Roman goddess Minerva:
Minerva is located at the landing on the staircase leading up to the overlook. Tour groups are allowed up to the overlook one at a time, and nobody is allowed to stop at the Minerva mosaic. The only way to photograph her is from across the room.
The overlook looks down into the Reading Room. It sounds like anybody needing to do research can obtain a library card and use the resources, including the Reading Room. As mere visitors, we were restricted to looking down from above.
The Library of Congress holds one of three existing Gutenberg Bibles printed on vellum; the other two are in Europe, housed in Paris and London.
The docent described how Gutenberg had to set, by hand, every single letter on each page he printed, and that he needed a way to organize all of the letters so he could find them easily and use them again. He decided to put all of the capital letters on the upper levels of his shelves . . . which is why we call them 'upper case' letters! And the lower case letters were, of course, organized in the lower levels of the shelves. I had no idea how or from where we inherited that terminology. If Gutenberg had put all the capital letters in boxes on the floor, 'upper case' and 'lower case' would mean the exact opposite of what they do mean!
Thomas Jefferson's library is housed in this building, as well as memorabilia from Bob Hope. It also holds much of the estates of George and Ira Gershwin, some of which is displayed in the Gershwin Room, opened as a permanent exhibit in 1998. We got to see George Gershwin's piano! It's a black Steinway grand, a smaller version of what you'd see in any concert hall and doesn't look particularly special until you consider the musical genius of the man who sat at it and composed Rhapsody in Blue and An American in Paris. Not to mention Porgy and Bess. I mean, WOW!
It doesn't get more American than that, does it?
Smithsonian National Museum of Natural History Finally, on the afternoon of our last day, we got to visit the NMNH. My friend, Dr. Chris Mah, works in the Invertebrate Zoology department of the NMNH. We arranged to meet him outside the staff entrance so we could bypass the ginormous line, then wandered the hall for a couple of hours before meeting up with him again for a tour of the behind-the-scenes stuff.
To be honest, while I love exploring any natural history museum, this one was too crowded for me to relax and enjoy. Again, it was because I was there during spring break, and all of the museums were especially packed with visitors. We had time to wander through the Ocean Hall, the fossils, and the minerals and gems. The minerals and gems are often my favorite part of a natural history museum, because (a) I'm not a geologist, so there's always stuff for me to learn; and (b) I love the colored minerals. I don't covet precious gems because of their monetary value, but I do love looking at them for their brilliant colors.
I took only one good picture on the main floor of the museum--there were too many people around for me to be able to take the time to frame shots nicely and after a while I gave up. But this is the fossil skeleton of a whale ancestor. Note that this animal didn't have just the pelvic bones that modern whales have; it had fully formed hind limbs. The most recent thinking is that Ambulocetus natans was entirely aquatic, but may have been able to walk around on the seafloor even if it never came out onto land.
The real treat for us was meeting up with Chris again at the end of the day. Chris took us through the security doors to the Invertebrate Zoology department, where the various collections are housed. This is where all the cool (and bizarre) stuff is kept. Most of the items are not going to be displayed, but are used by scientists studying particular groups of animals. Chris works at the NMNH but also travels to museums in California, Paris, and Tokyo to identify sea stars in those collections. The bowels of a museum are like the bowels of any other building--fluorescent lighting, dingy walls, old posters and whiteboards on the walls.
This was the best door sign. In recent years the federal museums have undergone reorganizations and consolidations. I don't know why and forgot to ask Chris, but the Invertebrate Zoology department inherited the entire National Parasite Slide collection. I bet it's a huge collection of parasites sectioned and mounted on slides.
In one of the collection rooms, sitting against the wall, was one of the most godawful objects I have ever seen.
It's a giant clam shell (Tridacna sp.) mounted on a silver base of mermaids. At first I thought it was a bathroom sink, but Chris said it's a punch bowl. Apparently there's a whole set of punch cups that go with it. The whole shebang was a gift to one of the early 20th-century presidents. Seems it might be a better item for the American History Museum, but may be they got right of first refusal and refused to accept it. Or maybe because of the clam shell the IZ department wanted it? Doubtful.
The collections are housed in movable shelves, in some order that hopefully makes sense to both the curators (people who decide what goes where) and the scientific users. Here's a bit of the coral collection:
Items that are being actively studied or need a temporary place while their permanent home is being decided or made ready end up spread out on big tables. This is the kind of thing that I find fascinating. The detritus of working scientists is fun to examine.
These are freshwater bivalves:
Chris said that the museum acquires items from a variety of sources: private collections, smaller museums or schools that can no longer keep all of the material in their own collections, and donations from individuals. Some of the artifacts are quite old, and arrive in quaint containers such as these nostalgic match boxes. Other things are packaged in paper towels and plastic bags. This, of course, is for dry specimens. Wet specimens, preserved in alcohol or formalin, are stored in buckets elsewhere.
Chris showed us some specimens that were of special interest to this marine biologist from California. The first were some brittle stars, Ophiocoma aethiops, collected by Ed Ricketts! Get a load of the label on this box:
There were four other boxes of the same animal. The date (March 20, 1940) and location (Espiritu Santo) indicate that this specimen and the several others just like it were collected during the trip that Ricketts and Steinbeck immortalized in their book Sea of Cortez. I read this book every so often, and use bits of it in lectures. I know that most of Ricketts' collection was deposited with the Hopkins Marine Station, part of Stanford University in Pacific Grove, after his death, and it was really cool to see this set of specimens in the Smithsonian.
The other special item that Chris likes to show visitors from California is the type specimen of one of our local sea stars, Pisaster giganteus. Before the onset of sea star wasting syndrome I'd see this star occasionally in the low intertidal, and divers would see it subtidally in kelp forests. The biggest one I'd ever seen was probably about 23 cm in diameter, a bit larger than my completely outstretched hand. What the Smithsonian has in its collection, for reasons that I don't remember, is the type specimen for this species. The type specimen is the individual (or group of individuals) that is the basis for the scientific description of a species and the species' name. You can think of it as the 'default' for a species, with an important caveat. Many times a species is named based on a type specimen that turns out to be not the norm for the species, which is why we encounter scientific names that are descriptive but make no sense.
Anyway, here's the type specimen of P. giganteus:
The tag says that this animal, which indeed lives up to its species epithet, was collected from Tomales Bay in 1857. It's easily three times the diameter of the conspecific stars that I've seen alive. And even in photos of subtidal stars, I haven't seen a P. giganteus this big. Do they just not get this big anymore? Does it have something to do with habitat? I wouldn't have expected to find P. giganteus in Tomales Bay, because I usually associate them with a rocky bottom in a more exposed habitat. So what's going on with this type specimen? I don't know, maybe nothing. This thing is remarkable for its huge size, though. Stuff like this is very cool. I always like going backstage and getting to see things that will never make it into the exhibit hall.
I like to venture out of my comfort zone every once in a while, as that's the only way to keep learning. Even though my particular area of interest is the marine invertebrates, there are a lot of other aspects of marine biology that are almost as interesting. And if I'm going to call myself a naturalist I should extend my knowledge in as many directions as I can, right? Besides, going out and learning new stuff is a lot of fun!
Shortly after the new year I went up to Año Nuevo State Park to see the northern elephant seals (Mirounga angustirostris) at their winter breeding rookery. Of course, I've known about the rookery ever since I came to Santa Cruz and have had friends in the Ph.D. program doing their dissertation out there, yet for whatever reason I never managed to get out there during the breeding season. The park is open all year, but while seals are on the beach for breeding the trail out to the rookery is accessible only via docent-led tour. This year I remembered to buy tickets ahead of time, to ensure that we'd be able to see the seals on a day we had time to do so.
The day we went, a Thursday, was threatening to be stormy, so we took our rain jackets just in case. We met up with our docent, a woman named Trevlyn, and hiked out to the beaches. Before we got there, though, we saw a mother bobcat (Lynx rufus) and her two kittens. This particular mom is well known to the folks at the park, who see her frequently. Because of the overcast skies, these normally crepuscular wild cats were active in the middle of the day.
And here is one of her kittens. There were two, but they were much shyer than their mom and hesitated to come out of the bushes.
Both of the kittens looked healthy, alert, and well fed. It looks like the heavy rains of the 2016-2017 season resulted in an abundance of prey--everything from insects to rodents to rabbits to birds--for carnivores, including bobcats. Given the bobcat's variable and adaptable diet, the future looks bright for these kittens who were lucky enough to be born in a state park. They (and their prey) will not be poisoned by pesticides or herbicides or hunted by humans, although it is likely that mountain lions (Felis concolor) prowl these trails as well.
Before arriving at the rookery we stopped so that Trevlyn could go over some elephant seal biology and give us the rules for visiting the beaches. The rules were: (1) stay behind Trevlyn at all times; and (2) do whatever she says without question. These animals are BIG and can move surprisingly fast over short distances. We were there at the early part of the season and there were only a few hundred animals at the rookery. But later, after all the adult animals have returned to land and the pups are born, it gets very crowded and stinky.
Elephant seal biology
The northern elephant seal is a highly pelagic animal, coming to land for two purposes at different times of the year: to breed in the winter and to molt. While they are hauled out for either purpose they do not feed, and survive on blubber reserves accumulated during the months foraging at sea. The different demographic groups (pups, juveniles, adult females, and adult males) haul out at different times of year.
The breeding season begins in mid-November, with the adult males arriving first. As they are staking out beach territory the females start arriving about three weeks later. They are pregnant and usually give birth a few or several days after their arrival.
A female who has given birth spends all of her time resting and nursing her pup. See how the pup in the photo above is sort of skinny, with wrinkled skin? This tells us that it is only a couple of days old. As it continues to nurse that loose skin gets filled out and the pup gets nice and fat. In the meantime, its mother is fasting while she nurses, and loses a significant portion of her bodyweight.
Sometimes the juvenile males, who have not yet proven their worth against an established bull male, get a little overexcited and try to mate with a female who has just given birth. These females are not receptive because, well, they've just given birth and have not yet gone into estrus. Watch this female above rebuff the attention of a juvenile male. Trevlyn told us that females try to rest near the larger bull males, whose presence will keep the juvenile males in line. Oh, and those markings on the young male? Those are made with ordinary hair dye, to identify the animals being studied.
Pups nurse for 28 days, then are abruptly weaned when their mothers mate and return to the sea. At this point the pups are called weaners. Weaners can't follow their mothers to the sea until they molt their pup fur and learn how to swim. They usually head out around early May, when they become fodder for white sharks lurking just offshore. The sharks ain't stupid.
The spectacular showdowns between adult male seals fighting for mating rights should be starting up about now.
Adult males are by far the largest animals on the beach. They also have a much larger proboscis. And see that pinkish stuff on the neck? That is thickened, callused skin that forms when the animals are fighting. As two bull males charge into each other they rear back and then slam forward, trying to gouge each other's neck with their teeth. The fights are not deadly but can become quite bloody before the loser decides to give in to the dominant male. While they aren't fighting or mating the males are resting to conserve their energy. This early in the season there is plenty of space on the beach and things are pretty serene, although as animals continue to arrive and pups are born, the fighting and mating will begin in earnest and there will be a lot more activity.
But at least as of early January, youngsters like these yearlings can relax on the beach without having to worry about being run over by males weighing up to 2500 kg.
Año Nuevo Island lies just offshore. When northern elephant seals began to return to this part of California they established their first breeding colony on the Island. Many pinnipeds, as well as seabirds, breed on islands because they are protected from land predators. In the case of the northern elephant seal, the major land predator was the grizzly bear.
Problem is, Año Nuevo Island has limited beach real estate. Elephant seals can't climb up even short cliffs, so can come ashore only on sandy beaches. The last wild grizzly bear in California was spotted in 1924, and since then the elephant seals have began taking over the coastal beaches near the island. All told, some couple thousand elephant seals will be on the beach at Año Nuevo this winter. This is a small rookery; the rookery south at Piedras Blancas is much larger. The northern elephant seal population in California seems pretty robust, with the animals having recovered nicely after being hunted to near extinction at the end of the 19th century. In these days when all news about the environment seems to be doom and gloom, it's nice to hear of a wildlife species doing so well.
The other day I was walking along Pescadero Beach about an hour north of where I live. My husband and I had gone on a short afternoon hike in Pescadero Marsh and decided to return to the car via the beach. It was a windy afternoon, making photography difficult, but I did enjoy the chance to get out, stretch my legs, and observe some nature. The ocean was quite lively, and as always it was fun watching surf scoters playing in the waves crashing on the beach. These ducks breed in freshwater lakes in northern Canada and Alaska, but spend their winters along the Pacific and Atlantic coasts of North America, where they forage on small invertebrates.
High on the beach well above the high-tide line we spotted some little brown puff balls, perfectly colored to match the sand and tiny enough to disappear completely in the divots formed by the footsteps of previous beach combers. They would run along the sand and duck behind a small hillock of sand, where they would be protected from the wind and from visual predators. See how well they disappear?
These are the delightful snowy plovers in their winter plumage. The field guides describe them as inconspicuous, pale little birds, which they certainly are. Unlike the sanderlings and other 'peeps' that frequent our beaches, which gather in large flocks and run away from both waves and people, snowy plovers react to human presence by hunkering down in small depressions and relying on their cryptic coloration for protection. Snowies live in California year-round, but I see them usually in the winter and spring. They nest in the sand, laying eggs in small depressions lined with shells, pebbles, and other like debris. Both parents incubate the clutch of 3-4 speckled eggs, which hatch into speckled nestlings.
It's this habit of nesting on sand that imperils the snowy plover. They are not as a species considered endangered, but some populations are declining. Human activities and the presence of dogs on beaches disrupt breeding birds and destroy eggs. Such tiny birds have a high metabolism and need to feed constantly. Every time they are disturbed into running away from humans they expend precious energy that they cannot spare. This is why some beaches where snowies are known to be nesting are closed to humans during the nesting season.
So if you see one of these signs on the beach, stay out of the fenced areas and keep your eyes open for tiny sand-colored puff balls. Even when the birds are not breeding they should be left alone and watched from a distance. Use your binoculars to get a close-up view of them.
There are certain creatures that, for whatever reason, give me the creeps. I imagine everyone has them. Some people have arachnophobia, I have caterpillarphobia. While fear of some animals makes a certain amount of evolutionary sense--spiders and snakes, for example, can have deadly bites--my own personal phobia can be traced back to a traumatic childhood event involving an older cousin and a slew of very large tomato hornworms. Even typing the words decades later makes me want to rub my hands on my jeans.
But enough about caterpillars. This Halloween I want to share something that isn't nearly as disgusting, but can still creep me out sometimes. Commonly called skeleton shrimps, caprellid amphipods are a type of small crustacean very common in certain marine habitats. They are bizarre creatures, but a close look reveals their crustacean nature. For example, they possess the jointed appendages and compound eyes that only arthropods have.
Around here the easiest place to find caprellids is at the harbor, where they can be extremely abundant. The last time I went to the harbor to collect hydroids for my class, the caprellids were swarming all over everything. When I brought things back to the lab I had to spend an hour or so picking the caprellids off the hydroids. I don't think they eat the 'droids, but they gallop around and keep messing up the field of view, making observation difficult. They're essentially just a PITA to deal with, and everything is easier after they've been removed.
Caprellids are amphipods, members of a group of crustaceans called the Peracarida (I'll come back to the significance of the name in a bit). They have the requisite two pairs of antennae that crustaceans have, and seven pairs of thoracic appendages of varying morphology. Some of these thoracic legs are claws or hooked feet that like to grab onto things. A caprellid removed from whatever it's attached to and placed by itself in a bowl of seawater thrashes around spastically. Only when it finds something to grab does it calm down. Even then, they attach with their posterior appendages and wave around the front half of the body in what I call the caprellid dance: they extend up and forward, and sort of jerk front to back or side to side. It isn't pretty.
A bunch of caprellids removed from their substrate and dumped into a bowl together will use each other as something to grab. This forms the sort of writhing mass that makes my skin crawl. I was nice enough to give them a piece of bryozoan colony to hang onto, but even so they ended up glomming together.
Now, back to the thing about caprellids being peracarids. The name Peracarida means "pouch shrimp" and refers to a ventral structure called a marsupium, in which females brood their young. Males don't have a marsupium, so adult caprellids are sexually dimorphic. When carrying young, a female caprellid looks like she's pregnant. See that caprellid in the top photo? She's a brooding female. That's all fine, until her marsupium itself starts writhing. This ups the creepiness factor again. Here's that same brooding female, in live action:
Crustaceans obviously don't get pregnant the way that mammals do, but many of them spend considerable energy caring for their young. Well, females do, at least. A female caprellid doesn't just carry her babies around inside a pouch on her belly. Although she isn't nourishing them from her own body in the way of mammals (each of the youngsters in the marsupium is living off energy stores provisioned in its egg), the mother does aerate the developing young by opening and closing the flaps to the marsupium. This flushes away any metabolic wastes and keeps the juveniles surrounded by clean water. As the young caprellids get bigger, they begin to crawl around inside the pouch, and eventually leave it. They don't depart from their mother right away, though; rather they cling to her back for a while, doing the caprellid dance in place as she galumphs along herself.
Until the juveniles strike out on their own they form a small writhing mass on top of a female who can herself be part of a larger writhing mass. And the sight through the microscope of all these long skinny bodies jerking around spasmodically can indeed be very creepy. Fortunately not as creepy as caterpillars, or I wouldn't be able to teach my class or go docking with my friend Brenna. And it's a good thing caprellids are small, 'cause if they were any bigger. . . just, no.