Cnidarians

Carol and I went to Pescadero Natural Preserve today. It was delightfully cool (about 70 degrees) with high fog blocking much of the sun. The tide was quite low when we arrived, so I wandered around looking at the variety of organisms in tide pools: sea anemones, crustaceans, molluscs, seaweeds, etc. Then we decided to walk to the mouth of Pescadero Creek and head up into the marsh.

As we followed the creek upstream under the Highway 1 overpass, Carol noticed that there were dozens of jellyfish washed up along the high tide line, translucent organisms looking a little like plastic bags filled with water. Most of the organisms were damaged; some had obviously been stepped on, some appeared to have broken in pieces, some no longer had a definable shape. I walked closer to the water, and began to find a few organisms that looked less damaged; one in particular, shown in the photograph below, retained a good deal of its structure:

When we got home, I did some online research to find out what kind of Cnidarian this was. I concluded it was a Moon Jellyfish, the common name of Aurelia species; most likely Aurelia labiata, which the authorities I consulted online agreed was the Aurelia species found along the San Mateo County coast. More specifically, what I saw was most likely the central morph of Aurelia labiata, the type specimen of which came from Monterey Bay (M. N. Dawson, Macro-morphological variation among cryptic species of the moon jellyfish, Aurelia [Cnidaria: Scyphozoa], Marine Biology [2003] 143:369-379).

Based on this tentative identification, I made two drawings of some of the structures that might be seen in the photograph. The first is based on Dawson (2003), and shows the organism from the underside; this approximates what you see when the jellyfish is lying flattened out on the sand, as in the photograph. The second drawing, based on a drawing by Richard Fox of Lander Univ., shows the organism as if it were alive and floating in the water.

The gonads are clearly visible in the photograph (note that the gonads and gastric pouch are right next to one another, so the gastric pouches are also visible). The manubrium and stomach in the center show fairly clearly. I did not see any tentacles when I looked at the organism, and none are visible in the photograph; this is not surprising as they would be quite small. Some of the radial canals are visible, enough to give the sense that the organism has radial symmetry. But the organism in the photo appears to have disintegrated somewhat.

The organism I photographed, and most of the Moon Jellyfish I saw stranded along the creek, were clear to translucent. One of them, though, was amber-colored; others had dark red or purple structures. The Encyclopedia of Life Web page on Moon Jellyfish, citing an article by the Monterey Bay Aquarium, states that Aurelia labiata are translucent when young, turning “milky white, sometimes with a pink, purple, peach, or blue tint” at maturity. So most of the individuals I saw were, apparently, young jellyfish.

Carol and I walked around the marsh for a couple of hours, and came back to the creek as the tide was beginning to flood again. I watched the tide pick up some of the stranded jellyfish, hoping to see some signs of life. One or two of the jellyfish floated away, looking intact, with their bells extended; perhaps they survived their exposure. But most of them sank beneath the water, or crumpled up, or seemed to be coming apart; it seems very unlikely these individuals survived.

Drawings revised, July 20.

More info: Article on Aurelia labiata on the Animal Diversity Web provides links to several academic references.

Note on my drawings: In making the drawings, I began with the cited sources, then consulted various online photos identified as Aurelia labiata. I saw significant variation in online photos, especially as regards tentacle length; since my drawings are not made from living specimens, they should be taken as schematic drawings, not accurate representations of live individuals.

Principles behind Sunday school Ecojustice class

Here are some of the principles behind the Ecojustice class taught at the Unitarian Universalist Church of Palo Alto (UUCPA) for the past five years.

Ecojustice class is a Sunday school program for gr. 6-8. Ecojustice class is a learner-centered program, with a flexible curriculum that can follow the interests of the teens and the teachers. We have a firm commitment to making the class as hands-on as possible — an emphasis on doing, rather than discussion. Rather than just projects done by one individual and intended for themselves, our projects tend to be done as a group and intended for use by the class, congregation, or a wider community. Ecojustice class can best be described as a “emergent curriculum,” meaning we’re often making it up as we go along; nevertheless, we have evolved some pretty firm organizing principles which may be of use to others.

Our definition of “ecojustice”:
A sign is posted in the classroom which gives our definition of “ecojustice”:

Ecojustice =
— humans treating other humans with dignity & respect
AND
— humans treating other organisms & the whole ecosystem with dignity & respect

If teens ask: “Why can’t we just say ‘Ecojustice means humans treating each other and the rest of the ecosystem with respect’?” — we can explain that white environmentalists have been criticized because they worry more about non-human organisms than they worry about humans who have a different skin color. So we want to make sure we always remember that environmental action cannot be separated from human justice.

Basic class plan is the same every week:
I/ Attendance & chalice lighting (typically indoors)
II/ Check-in (typically indoors)
III/ Reading (typically indoors)
IV/ Project for the week (most often outdoors)
V/ Closing circle (often outdoors)

Reading: Each reading is related in some way to ecojustice. We adults can read the reading, or ask the teens if one of them would like to read it. Then maybe have a brief conversation about what the reading tells us about ecology, ecojustice, or the natural and human worlds.

Project for the week: Projects may last from 1-4 weeks. Teachers pick projects based on their interests and abilities. We try to include a conversation with each porject about why we are doing the project: “what does this project have to do with ecojustice?” This can take place while we’re working, or as part of the closing circle.

Closing circle: During closing circle, have the teens say one thing they learned, or one thing they’re taking away from this class. End with the UUCPA unison benediction (used in all classes); the unison benediction is posted in classrooms in 4 languages, reflecting languages spoken by people in our congregation (English, Spanish, German, Hindi; working on a Mandarin version).

Topic areas:
We relate any project that we develop to one of seven topic areas. Those topic areas are listed below, along with sample projects that we have either completed or plan to carry out (in parentheses).

1. Food
Tire Garden — based on the UUSC Haiti tire garden project
Ongoing Gardening — digging, planting, weeding, watering, etc.
Cooking projects — using, e.g., organic ingredients

2. Energy
Rocket Stoves — based on a design by Larry Winiarski
Solar Cooking — using various solar ovens (solar s’mores esp. popular)

3. Water
Rain Barrel — installed a rain barrel; use the water to irrigate the gardens
Clay Pot Irrigation — low-water use irrigation method
(Bucket Drip Irrigation — low-water method for irrigating garden)

4. Waste
Composting — assembled two composting bins; maintain them
(Build a composting toilet)

5. Habit and Shelter
Wildlife — “tracking pit”; invertebrate observation; building birdhouses
Native Plants — tour of church’s native plant garden
Habitat for native pollinators — making “bee houses”
Support local homeless shelter which stays at our church in Sept.
(Using Natural Herbs — planned visit from a local herbalist)
(Natural Dyes — tie-dye using redwood cones and fennel)

6. Earth and Air
Disaster Plans — making a personal “go-kit” in case of wildfire evacuation
(Global climate change project — but how to make it hands-on?)

7. Toxics in the Environment (new category added in 2018)
(E-waste)
(Phytoremediation — using plants to remove toxics from the soil)

More info about each of these topic areas is below. Continue reading “Principles behind Sunday school Ecojustice class”

Beams, Concord, Mass.

Carol and I went to the Robbins House, an early nineteenth century historic house at the Minuteman National Historic Park in Concord, Mass. The house was originally occupied by Susan and Peter Robbins, two grown children of Caesar Robbins, and perhaps by Caesar Robbins himself; I say perhaps, because the history and chronology of the house, as set forth on the Robbins House Web site, is not entirely clear to me. This is not surprising, given how poorly documented African American lives of the early nineteenth century were. What’s important to know is that Caesar was an African American man who won his freedom from slavery by serving in the American Revolution, and the house was occupied by his descendants and extended family until about 1870.

We got an excellent tour from one of the interpreters, who told us a great deal about the people who lived there, and about the social history surrounding the house. But I have to admit what interested me was the construction of the house. I was particularly interested in the exposed roof beams in one room, which included both hand-hewn beams and sawn joists. The sawn lumber was manufactured using a vertical saw, not a rotary saw. Why the mix of hand-hewn and sawn lumber? The hand-hewn beams could have been salvaged from an older structure, something that was often done in the early nineteenth century, or they could have been made for that house; the sawn lumber could have replaced older joists, or they could have been original, though sawn lumber would have been more expensive than hewing one’s own beams. When the house was being restored, there were archaeology, dendrochronology, and other architectural studies were carried out; I hope the non-profit organization that operates the house publishes the tests and tells us why there are two kinds of beams.

Dusk

The past couple of evenings, the wildfires north of here have given us sunsets that are more colorful than usual. Tonight I went out and walked around the cemetery at dusk; the light was rosy with a yellowish tinge. I went up to where you can look out at San Francisco Airport, and watched a couple of jetliners land. A bank of fog was stretched from the Golden Gate across the Bay towards Oakland; an avalanche of fog curled over the top of San Bruno Mountain; here in San Mateo, the fog was several hundred feet above me, pushed upwards as it moved up the Crystal Springs Gap. Then I happened to look up, and there was a pair of White-tailed Kites hovering overhead, silhouetted against the bright low clouds; they worked their way down the hill, and for a few minutes I watched them come to a hover every minute or so, until they disappeared farther down the hill behind some trees. The rosy glow from the sunset really was lovely, even with the realization that a good bit of that lovely redness came from wildfire smoke.

Bay Area Sacred Harp

Some Stanford University undergraduates made a brief documentary on the Bay Area Sacred Harp singing community. The students were in an ethnomusicology class, and their goal was to document a local musical community. Given their time constraints, I think they give a pretty good sense of how music and community are woven together in Sacred Harp.

Notes: No one is identified in the video, but this is who you’ll hear from, in order of appearance: Pat Coghlan, Gridley, Calif.; Lena Strayhorn, San Francisco; Jeannette Ralston, Half Moon Bay; Terry Moore, Palo Alto. (Jeannette is the senior singer who was interviewed; she has been singing Sacred Harp in the Bay Area since the 1970s.) The local singings shown are Berkeley (in the church with pews); Palo Alto (in the children’s art room); and San Francisco (in the living room). You’ll hear the Palo Alto singers on Nehemiah Shumway’s Ballstown (begins 0:05; cont. 0:27 and William Billings’s Easter Anthem (begins 1:58).

Adventures in grilling

It was hot today, so we decided to grill our dinner. I hardly ever eat beef any more (can’t afford it, it’s bad for me), but Carol had gotten some local grass-fed beef from a nearby farm, so we grilled hamburgers and potatoes. That wasn’t quite enough for a dinner. Carol saw that we had a small mild white bitter melon in the refrigerator — what about grilling that? She basted it in olive oil and rosemary before she grilled it. It turned out well — slightly crispy, nicely bitter, very yummy.

Bioregional quiz

In the Winter, 1981, issue, the editors of the magazine Coevolution Quarterly published “Where You At? A Bioregional Quiz,” developed by Leonard Charles, Jim Dodge, Lynn Milliman, and Vitoria Stockley (you can find this quiz online here). The quiz was later republished in the book Home: A Bioregional Reader (New Society, 1990). Since then, others have modified the quiz; most notably, in 2006 Kevin Kelly posted a revised version of this quiz titled “The Big Here” on his blog.

As much as I like the original version of the quiz, some of the questions are specific only to certain bioregions, such as “What spring wildflower is consistently among the first to bloom where you live?” — if you live in a region where flowers bloom year-round, there is no good answer to that question. And some of the questions are maybe too difficult, such as “Name five grasses in your area” — I’ve been trying to learn how to identify grasses down to the species level, and it’s very challenging. A couple more things bother me about the quiz. First, the quiz focuses too much on book knowledge; you are merely asked to “Name five resident and five migratory birds,” you are not asked to identify them in the field. Second, the quiz ignores whole clades of organisms that would have been familiar to indigenous peoples, such as invertebrates and non-vascular plants.

So I’ve been thinking about how to revise the quiz. I wanted to create a quiz that would prompt me to learn more about my watershed, and to encourage me to get outdoors and explore that watershed. The first draft of my quiz appears below. How many answers did you get? What did I leave off that I should have included?

Continue reading “Bioregional quiz”

Lichens

Living in a cemetery gives me the opportunity to observe a nice diversity of lichens. I went out this evening to see some of this diversity; my camera served in stead of a hand lens.

This crustose lichen, covering an area about the size of a quarter, was growing on a marble gravestone. The magnification of the photo shows how the lichen has etched an indentation into the stone. To make an accurate identification of crustose lichens, I’d need both a microscope and far more knowledge than I currently have. But this may be in the genus Caloplaca: “The 25 to 30 species [of Caloplaca] reported from California … occur very widely on trees and mostly calcareous rocks. Caloplaca saxicola is common and one of the first crustose lichens collected by beginners” (Mason E. Hale Jr. and Mariette Cole, Lichens of California [Berkeley: Univ. of Calif. Press, 1988], p. 190).

The foliose lichen above, about an inch across, and found on a piece of granite, may be in the genus Xanthoparmelia. According to Hale and Cole, “Xanthoparmelia is by far the dominant foliose lichen on granites, schists, shale, and other non-calcareous rocks throughout California…. Two species, X. cumberlandia and X. mexicana, are common and collected almost everywhere in the state.”

If I were to get serious about identifying lichens, I’d need to go out and get the K, C, and P reagents, an inexpensive USB microscope, and a few other things. Then I’d have to get serious about studying them: dissecting them, looking at them under the microscope, etc. Is it enough to just look at lichens without identifying them? or do I want to engage in more serious study of them? Heraclitus advised that “those who are lovers of wisdom must be inquirers into many things indeed” (DK35); but how deeply should one inquire into each of those many things? One only has so much time in this world; a serious in-depth study of one topic means less time to inquire into the many other things.