March 3, 2014
Turning over rocks in one of the Dry Frio's many shallow and very modest rapids, nowadays beneath many rocks you find dragonfly naiads, stonefly larvae and the like, plus often there are interesting little gobs of transparent, jellylike substance adhering to the stones' submerged undersides, as shown at http://www.backyardnature.net/n/14/140302sn.jpg.
Beneath a hand lens you see that each blob contains several creamy-white items appearing to be suspended in their own orbs of gelatinous material, as shown at http://www.backyardnature.net/n/14/140302so.jpg.
I saw this kind of thing when I was a kid with an aquarium back on the farm in Kentucky, and I knew that they were snail eggs. When you do a search engine image-search on "snail eggs" you see that snail eggs come in many conditions, sometimes forming clusters like tiny, dry ping-pong balls stuck to grass stems, some like clumping grains of pinkish sand, and others in different forms, including having the eggs embedded in jelly. Some jelly-producing species deposit narrow bands of jelly, others round daubs of it, some croissant-shaped, etc.
By far the most commonly occurring aquatic snail in the Dry Frio is what we've called the Tadpole Snail, and profiled at http://www.backyardnature.net/n/a/tadsnail.htm.
Picture's of Tadpole Snail eggs on the Internet look pretty much like ours, so probably our picture shows Tadpole Snail eggs. Tadpole Snail egg packages contain between 20-400 eggs, usually less than 50, so our globs are particularly small. In warm climates the eggs hatch in a couple of weeks. The embryo and its spherical, gelatinous egg material is referred to as an egg capsule. Egg capsules are in turn suspended in a gelatinous egg mass.
Tadpole Snails are hermaphrodites; they can mate with one another, or with themselves.
SILKEN CONE BENEATH A ROCK IN THE RIVER
Beneath a flattish, limestone rock mostly submerged beneath fast-flowing water at a tiny rapids in the Dry Frio, something turned up I'd never seen: Between the size of a BB and a small pea, it was ram-horn-shaped and made of something like smooth, cream-colored paper or plastic. The open end of the horn seemed to be sealed inside with a silken lid, and the horn's opening was pointed downstream so that hydrodynamically it offered the least possible resistance to the flowing water. A diminishing carpet of silk issued from the horn's opening across the rock surface. All this can be seen at http://www.backyardnature.net/n/14/140302cc.jpg.
Aquatic spiders don't appear to create such structures. After eliminating that idea, neither volunteer identifier Bea in Ontario nor I had any idea who might have constructed such an elegant and mysterious little object. Bea submitted the picture to BugGuide.Net's identification-needed page. For a whole day there was silence as bug connoisseurs all across the planet scratched their heads, but finally Mark Melton in California commented that certain black flies produce similar cocoons for their aquatic pupae. Pursuing that lead, eventually pictures and drawings were found matching our discovery.
So, I'm fairly sure that our photograph shows the cocoon of a pupa of one of many species of black fly, genus Simulium. Another piece of evidence supporting the theory is that two weeks ago in our February 16th Newsletter we profiled a population of black fly larvae, prettily shown at http://www.backyardnature.net/n/a/simulium.htm.
Remember that the formula for insect complete metamorphosis, which is practiced by the Fly Order, the Diptera, is:
egg --> larva --> pupa --> adult
Therefore, earlier, in a similar environment with fast-flowing, well oxygenated water in the Dry Frio, we saw black fly larvae, and now some of those larvae have metamorphosed to pupae. Black fly pupae encase themselves in silken cocoons, or cases, attached to aquatic vegetation or other objects in streams. When a submerged pupa metamorphoses into an adult, it slits through its silken case and floats to the water's surface on a bubble of air. Some species mate as soon as the adults emerge.
What a pleasure to find something new to me, and figure out that thing's secretes!
MALE MISTLETOE FLOWERS
Last week we looked at female mistletoe flowers, shown at http://www.backyardnature.net/n/14/140223mt.jpg.
This week some male plants turned up, and their flowers appear at http://www.backyardnature.net/n/14/140302mi.jpg.
As with the female flowers, male mistletoe flowers bear no petals but rather the sexual parts are enclosed within a fairly fleshy, three-lobed, hairy calyx forming a deep bowl. In the above photo notice the two-chambered, yellow anthers peeking from beneath the calyx lobes arching over them. Each flower produces three stamens topped with pollen-producing anthers, and each stamen is situated directly in front of its calyx lobe.
GREEN FELT BESIDE THE SEEP
To find unusual organisms it's helpful to look in unusual environments. The slightly unusual environment I visited that day was a small seep where the Dry Frio's waters emerged from the edge of a gravel deposit completely damming the little river. With the river's water as low as it is now, maybe most of the bed consists of dry gravel, but water still flows down the river, just filtering through one gravel barrier after another.
At this particular seep at first glance nothing looked special, except maybe for a small colony of filamentous alga or cyanobacteria at the water's edge. When I poked the green pad with a finger it was fairly firm, not soft and spongy like similar algal mats and rafts on and in the water. If felt like nudging a short-haired, fat, wet mouse. You can see what it looked like at http://www.backyardnature.net/n/14/140302va.jpg.
On hands and knees the hand lens displayed structures unlike I'd seen in any alga or cyanobacteria so far. On Y-shaped structures projecting from the filaments' sides were innumerable spore-like items so small that they were hardly visible, as shown at http://www.backyardnature.net/n/14/140302vb.jpg.
Having collected some filaments, back at Juniper House the microscope showed that the filaments weren't as straight and regularly formed as other filamentous organisms we've seen, nor were individual cells apparent, as has been the case with all the green, filamentous algae we've looked at so far. You can see a filament with calcite crystals adhering to it at http://www.backyardnature.net/n/14/140302vc.jpg.
A closer view showing individual green chloroplasts suspended in cytoplasm unrestrained by cell walls is at http://www.backyardnature.net/n/14/140302vd.jpg.
The lack of cell walls suggested that it was a cyanobacterium, not an alga. However, cyanobacteria we've seen so far have been encased in gelatinous sheathes, and these filaments didn't seem to be. Much more disorienting, however, were those spores held at the tips of the Y-shaped items branching from the filaments' sides; spores we've seen produced by both filamentous algae and cyanobacteria have been produced inside cells forming the filaments, or in conjugation tubes between adjacent filaments. A close-up of one of those strange Y-shaped branches bearing a spore at the tip of each branch is shown at http://www.backyardnature.net/n/14/140302ve.jpg.
Once again we've found something so unusual that it isn't represented on the usual freshwater-organism identification webpages, and I hardly knew where to begin to identify it. Once again I was reduced to browsing thousands of search-engine-generated thumbnails before finding a picture of something similar.
Our organism is a member of the genus Vaucheria, probably VAUCHERIA GEMINATA, sometimes appropriately known as green felt. The species occurs spottily worldwide and is described as a freshwater/terrestrial species, which applies well to the muddy pool edge where we found it, its top part barely emerging above the water's surface. Ecologically green felt is thought of as a stabilizer of exposed mud.
It's true that green felt's filaments lack the obvious cells with cell walls we've seen among the algae. Green felt species are "coenocytes." Coenocytes are organisms composed of a mass of protoplasm containing several nuclei that divide without the kind of cell division seen among regular green algae. Green felt filaments are occupied with large central vacuoles -- vacuoles being bags of water containing enzymes and more -- pushing against the surrounding cytoplasm and extending along the entire length of the filaments, except for the growing tips. Chloroplasts are located on the periphery of the cytoplasm with the nuclei gathering toward the center near the vacuole.
But, what kind of organism is green felt? In the old days green felt was regarded as a plant, and an alga. Nowadays some experts place it in a whole separate kingdom from that of plants, recognized only in 2005, the Chromalveolata. The Chromalveolata includes species descended from an organism consisting of one cell with a nucleus, known as a "bikont," which assimilated into its body a species of red alga, thus forming a symbiotic relationship similar to what we saw with the Green Paramecium a while back, which symbiotically carries photosynthesizing algal cells within it.
The novelty of being placed in a different kingdom from, say, the common Spirogyra alga in our Dry Frio, is that it means that the difference between green felt and Spirogyra is approximately that of the difference between a horse and an oak tree, which also are in different kingdoms.
It was a safari stalking exotic beings attached to a feathery, thumbnail-size, green leaf of the aquatic plant called Watermilfoil, from the Dry Frio River, now suspended in a drop of water on a slide beneath the microscope. Patiently surveying scenery along the midrib, the whole field of vision was animated with gyrating, spiraling, vibrating, hungry-acting microbes, like bees and flies in a tropical swamp. In this uncanny landscape suddenly inside an angle formed by the midrib of the Watermilfoil leaf and one of its pinnae, there appeared a branching tree as otherworldly as a Boojum, a green, weirdly segmented creation whose thick branches terminated in outlandishly long, slender, stiffly sharp-pointed hairs. You can see the whole thing at http://www.backyardnature.net/n/14/140302bb.jpg.
I guessed that it was a branching, filamentous alga, but I'd never seen an alga with such long hairs. You can see individual cells close up at http://www.backyardnature.net/n/14/140302bc.jpg.
By doing an Internet image search on the keywords "algae setae" -- setae are stiff hairs -- within seconds I found a match. We had a member of the genus BULBOCHAETE, a genus of about 110 known species, commonly known as Bulbochaete algae, with species occurring in a wide variety of freshwater habitats worldwide, but mostly in temperate and subtropical zones.
The alga body consists of three distinct kinds of cells: "holdfast cells," not visible in the pictures, anchor the alga body to its substrate; cylindrical "intercalary cells" are the green cells constituting the alga's main body, and; slender, transparent "hair cells" form the long setae. The hair cells, which number more than six and include an enlarged or "bulbous" one at the hair base, are what make this genus instantly recognizable by anyone who knows about the group, for such algal cells are unusual.
Each intercalary cell contains a single green, photosynthesizing chloroplast. Our last picture shows that each chloroplast bears several dark, spherical spots. These are pyrenoids, which are tiny organs, or "organelles," whose main function is to generate and maintain a CO2-rich environment around the photosynthesizing enzyme known as Rubisco.
In the little Dry Frio, this must be a fairly rare alga, for of all those seen during previous microscopic safaris in the river's waters, never has this species shown up.
LICHEN FORMING TINY PITS IN ROCK
We've seen that lichens come in endless variations, sometimes flashy and sometimes obscure, and that they can reproduce in surprising ways. A species encountered this week presented itself as little more than a white patch inside which a multitude of tiny pits occurred, the pits extending into the limestone boulder on which the lichen resided.
This lichen occupied an unusual substrate. Along a dry arroyo, or normally dry stream, it grew on boulders consisting of conglomerate rock which itself was composed of limestone pebbles and rocks cemented together with calcium-rich marl that hardened into rock-hard cement 110 million years ago. The original loose pebbles, rocks and mucky marl had accumulated at the bottom of the shallow sea that occupied this area early during the Cretaceous Period. You can see boulders on which this lichen species occurred at http://www.backyardnature.net/n/14/140302l1.jpg.
An apple-size splotch of the white lichen with its peppering of pits is seen at http://www.backyardnature.net/n/14/140302l2.jpg.
A close-up of the pits, which are no larger than pin-pricks, is at http://www.backyardnature.net/n/14/140302l3.jpg.
The white surface in that picture is the lichen's body, or thallus, consisting of no more than a flat plane of fungal hyphae in which photosynthesizing algal cells are enmeshed. The pits are remains of reproductive structures called "ascomata." The lichen produced an acid that dissolved the limestone below each ascoma, forming the pits. I read that eventually the ascomata in these pits issue their spores, then fall out, leaving just the pits. Crustose lichens growing on stone normally dissolve some of the stone, but it's unusual for a species to go at it in this manner. Ascomata sunk in pits in rocks are said to be "endolithic."
Having so few anatomical features to work with, I could identify this species only by searching for labeled pictures on the Internet. Of the hundreds of crustose lichen pictures looked at, the best match was with CLAUZADEA METZLERI, which the LichenPortal.Org website indicates has been collected in the Texas Hill Country near San Antonio, though it appears to be best documented in Eurasia. The only English name I can find for it is Clauzadea Lichen.
Not much information is available on this lichen's presence in North America, so I'm happy to document it here.
On an outcrop along the same arroyo but on harder limestone, another white, black-speckled, crustose lichen appeared, as if to emphasize how sharply one has to focus on subtle details when distinguishing these species. This one is shown at http://www.backyardnature.net/n/14/140302l5.jpg.
Its spore-producing apothecia appear at http://www.backyardnature.net/n/14/140302l6.jpg.
In the last picture, sunlight slants in from the side emphasizing the graininess of the thallus' surface. Our previous Clauzadea lichen's thallus was smooth and pitted with tiny black dots between the larger ascoma pits. Also, the Clauzadea's apothecia either were very deep in the pits or had matured and dropped out, while on this lichen the black apothecial surface is clearly visible and is concave.
But, couldn't this just be a younger phase of what we're calling Clauzadea? Maybe its fresher thallus is not yet pitted with tiny dots, and not yet weathered to smoothness. And maybe later these apothecia will drop out just like the previous species' appear to have done.
One reason I separate these two lichens is that the latter species' apothecia are larger than those of the Clauzadea. Also, on the Internet I find pictures at reputable websites whose Clauzadea metzleri pictures match the lichens above identified as Clauzadea metzleri, while other pictures match our current lichen. They are identified as BAGLIETTOA BALDENSIS, sometimes known as Verrucaria baldensis, and without a common name. Bagliettoa baldensis is common on limestone in Europe, especially the southern part, and appears here and there in the US, especially in the southern states.
It's awkward to assign names on the basis of such flimsy evidence, yet it's important to place our observations and pictures where experts can find them and use what they want. And they'll find this page just seconds after searching on the keywords "Bagliettoa baldensis."
Nowadays animals and flowering plants doing interesting things are relatively hard to come by here, not only because it's winter but because of the drought. The landscape is brown and dusty, the tall grass in fields and along roads has faded gray and bear no flowers or grains, and their blades are brittle and tattered.
So, instead of wildflowers we look at lichens and algae. Instead of mammals and birds, it's insects and snails. This is worth thinking about.
For, it's easy enough just to accept winter's monotony and grayness, while a certain mental switch is needed to go from scanning fields with binoculars to surveying rock surfaces with a magnifying glass, and a certain mindset must be cultivated before you can thrill to graceful pirouettes of a paramecium in a drop of water, when swallows aren't available in the sky.
For me, two main reasons make these efforts to change perspective worthwhile. First, it's just fun to discover all these rare, unusual and otherwise gorgeous and mind-boggling living things around me, which I've overlooked until now.
Second, on a spiritual level, it's comforting to see that the Universal Creative Impulse devotes exactly as much energy and art arranging details of the microscopic world as we see every day in the workings of macroscopic forests and fields. This supports the idea that the entire Universe is exquisitely ordered at every level. And since it appears that everything everywhere is changing, is evolving, then there must be some kind of plan. I can't resist the mental image of the Universe as an opening blossom, with us humans as part of that blossoming, looking around, in awe. That's the notion in which my spirituality is rooted.
Of course there's the same message -- in some ways even more vividly expressed -- when we shift our minds to "focus up," to behold the details of the unknowably vast and complex Universe beyond Earth.
Everywhere, everywhere, there's attention to detail, everything working smoothly, everything just as it should be, gradually evolving toward... what?
FEATURED ESSAYS FROM THE PAST:
"'Sales are Down'" from the May 17, 2009 Newsletter, at http://www.backyardnature.net/n/p/090517.htm
"Downsizing" from the September 4, 2011 Newsletter, at http://www.backyardnature.net/n/p/110904.htm
Best wishes to all Newsletter readers,
All previous Newsletters are archived at http://www.backyardnature.net/n/.