So now, I’ve finally arrived at this single-celled alga, Chlamydomonas reinhardtii, affectionately called “chlamy”, which I’ve observed in puddle water alongside the more spectacular colonial species.
This being probably the single most heavily-studied alga in history, I felt it deserved itself a good series of blog posts to cover all of the different aspects of its biology, history, applications and my personal connections to it.
But before then, here are some of the shots I’ve managed to capture of C. reinhardtii in situ, or in its natural habitat:
Chlamydomonasreinhardtii from puddle water, imaged at 100x.
Chlamydomonas reinhardtii is quite numerous in many of the puddles that Eudorina and Pandorina also inhabit, and like those two algae it tends to swim towards and cluster in the most strongly-lit area of a sample. This picture was taken at one end of a drop of water after about 2 minutes of letting it sit on the microscope slide, after which all of the chlamy had swarmed to that end, stopped swimming so erratically, and were easier to photograph.
Chlamydomonas reinhardtii, imaged at 400x.
As is evident at the closer magnifications, the cells of chlamy aren’t just uniform blobs of green (some species of algae unfortunately do just look like that, and they’re an absolute pain to try and identify by eye alone). In my next post, I plan to cover the basic anatomy of a cell of C. reinhardtii so that these features become more obvious and meaningful as I continue my discussion of the alga. Then, I’ll do an in-depth research post to dig up some of the history of C. reinhardtii. After that, I’ll cover some of the biggest areas of biology in which chlamy is currently being used, hopefully one post per topic. And finally, I’ll legitimately discuss my lab work for the first time on this blog as I show my own cultures of this alga and explain in brief my plans for them, both currently and as I move into college (the latter is of course subject to change). In between these posts, I’ll sandwich in some other interesting finds from my puddle water samples, including the colonial alga Gonium and hopefully the giant ciliate Bursaria truncatella. Lots of good stuff planned for the next couple of weeks. Stay tuned.
In my previous two posts, I covered some of the rotifers I found in puddle water collected right outside of my high school, so in this third post I figured I would take a short break from animals and talk briefly about what really excites me in that water – algae!
About a year ago, when I first moved to Sacramento and started attending this school, I noticed the puddles left on that street after the rains had an interesting color to them. As I walked past them for the first few days, it looked like this sort of very faint lime green color. Maybe some weird dirt, I thought. But as the days became weeks, that color became very apparent as it darkened, and I finally made the decision sometime in the fall to just collect some of that water and give it a look under the microscope.
And it was…really something special.
I did manage to culture one species of algae from that puddle last year, and the preliminary results from sequencing the DNA of that species suggested it might be undescribed and unnamed…but sadly, the culture died out last summer. So, with the rains returning this year, I’ve been making regular (weekly and twice-a-week) collections of puddle water, trying to start new cultures of algae and at least document in photos all of my finds.
In this post, I’ll be giving a very broad overview of the algae and their habitat, and then I’ll profile all of the interesting species more thoroughly in future posts (as there are lots that I want to talk about in more detail). Interestingly, while the sheer quantity of algae this year seems lower than it was last year (the water hasn’t turned completely green yet – perhaps the rains came later this year, so with the colder days, the algae haven’t been able to grow as fast? Idunno really), I’ve found many more species than I noticed last year, so I am sure I’ll have a lot to talk about.
What I did today was take a used plastic water bottle from a school recycle bin and fill it up with puddle water, and then take it home. Based off of previous experience, the algae and interesting animals will probably survive in here for a week or so before they all get eaten, die off or revert to a hibernating state (finding the lighting and temperature conditions in my lab unusual, and too risky to stay active in). Eventually, I’ll mix and match pictures from all of my collection trips so I get the full diversity of organisms (which I don’t always collect in a single go), but I just wanted to show you something very cool in this particular sample. It’s illuminated by a regular desk lamp, and the bottle has been sitting still for about an hour. During this time, some of the motile algae, which have the capability to swim, move over to the side of the bottle which is most strongly illuminated, clustering at the top edge of the water towards the light. But when I gently rotate the bottle 180 degrees, so the algae once facing the light then end up at the least-illuminated edge of the bottle, they quickly form these long “streaks” in the water:
Algae swimming in a bottle of puddle water (faint green patches to the right). Notice one larger streak towards the bottom, and a second region above it.
Rather than simply swimming around the top edge of the water, back into the light, a major population of algae elected to dive straight to the bottom of the water sample. What is very interesting is that this population of algae (the bottom streak) swam very fast and soon dispersed back into the water; however, a completely different group of species formed the streak and the tail above it, staying in the shallow water and swimming as the crow flies towards the light at a slower pace. I’ll cover these different species in greater detail later, but here’s a preview shot first, just to give you an idea of what these algae look like.
The “slower” species, which generally prefer to stay in most heavily-lit sections of the sample, are the most beautiful and impressive algae in this puddle:
Mixed colonial algae of the genus Volvocales, imaged at 40x.
The algae in this picture belong to the order Volvocales, family Volvocaceae, and the genera Eudorina and Pandorina (perhaps others, but I really have no clue; only if I ran DNA tests on them could I be sure). What’s really cool about them is that they are colonial; each large raspberry-looking “unit” is not a single cell but consists of several cells, coming in powers of 2 (typically 8, 16, or 32 for these species), which should be somewhat distinguishable even at this low magnification.
I’ll save the rest for later, but in the upcoming posts I’ll be sure to cover each of the unique species and strains that are represented in this picture, as well as even smaller single-celled algae that are also found in these samples. These posts, like my previous profiles, should contain some information from my own observations, the history of their discovery and description, some neat facts about their biology or importance, and of course, lots of pictures. By the end of it all, hopefully you’ll look at puddles in a whole new light. So stay tuned.
Epiphanes senta is a relatively large rotifer (visible to the naked eye), probably around 300-500 microns in length on average, that I think is the dominant species living in the puddles along the street outside my high school. Here is one of my favorite pictures of this species:
A smaller individual of Epiphanes senta, photographed at 100x.
Its defining characteristics to me include its generally slender profile (although it can contract and become fatter), conical tapering shape, and distinctive taller tufts of cilia on its mouth (typically three), which it uses to generate current to help it swim and collect the bacteria and algae it eats. This species also has a fairly large mastax (jaw).
E. senta, 100x.
Epiphanes senta was first described a good while back – in a book called Vermium terrestrium et fluviatilium, seu animalium infusorium, helminthicorum et testaceorum, non marinorum, succincta historia written by the Danish biologist Otto Friedrich Müller in 1773. A contemporary of Linnaeus, a lot of his work was microbiological; he helped pioneer the discovery and classification of many species of worms, the algal taxa diatoms and dinoflagellates, and the “infusoria” (a general term referring to most microscopic pond life; compare animalcule) using the then newly-developed binomial nomenclature system to name his discoveries. As microbial ecology continued to develop as a field, E. senta was observed and recorded from around the world, becoming known to scientists as a cosmopolitan species. By 1997, papers had been published documenting its presence in every continent, including Antarctica. However, ten years later, a study by Schröder and Walsh examined populations of E. senta collected in floodplains in Germany, deserts in Texas, and lakes in the mountains of Hawai’i, using a variety of tests such as DNA sequencing, interbreeding experiments and electron microscopy to conclude that the taxon Epiphanes senta did, in fact, consist of more than one species which appeared too similar to the (normal microscopic) eye to differentiate. Whether or not Epiphanes senta is global in distribution remains to be seen, but that study concluded by describing three new species, suggesting that other populations around the world may simply be close lookalikes and not one species.
As I currently am not able to identify exactly which species this rotifer is (whether E. senta proper or a close relative), I’ll simply refer to it as E. senta for now. What’s interesting, however, is that I do have all of the equipment and other materials necessary to do DNA-based identification of this species. When I recollect puddle water samples, perhaps I’ll try to culture some of these (rear them in captivity) or preserve some for DNA work, as a pet project or something like that. Perhaps this could be a new species!
Closeup of E. senta corona, 100x. Note the protruding tufts of cilia.
Like this population, which lives in a temporarily-submerged aquatic habitat, other populations and species in the E. senta complex (such as E. chihuahuaensis described in Schröder and Walsh 2007) have been found in ephemeral habitats which dry up and refill periodically with rainfall, typically emerging a few days after the pool fills. It has been noted too that populations of E. senta in permanent bodies of water also have temporary peaks as well as long seasonal absences from the microfauna. This may have to do with the availability of food – this species is commonly associated with eutrophic (nutrient-rich and often consequently algae- and bacteria-rich) waters, so it may choose not to compete past the spring and summer months, when food becomes scarcer, and lie dormant in the water before emerging again next year.
So, that’s a basic profile on Epiphanes senta. In my next post, I will cover another rotifer from the school puddles. Stay tuned.
Works cited:
Gilman, D. C.; Peck, H. T.; Colby, F. M., eds. (1905). “Müller, Otho Friederik”. New International Encyclopedia (1st ed.). New York: Dodd, Mead.
Ripley, George; Dana, Charles A., eds. (1879). “Müller, Otto Frederik”. The American Cyclopædia.
Schroder, Thomas, & Walsh, Elizabeth J. (2007). Cryptic speciation in the cosmopolitan Epiphanes senta complex (Monogononta, Rotifera) with the description of new species. Hydrobiologia,593(1), 129-140.
Spärck, R.(1932) “Otto Friedrich Müller” in: Meisen, V. Prominent Danish Scientists through the Ages. University Library of Copenhagen 450th Anniversary. Copenhagen: Levin & Munksgaard, pp. 60–64.
I’m Bowen Jiang, and I am a senior at Mira Loma High School in Sacramento, California. As the blog’s title, description, and images may have given away, I’m also a passionate algae scientist! I’ve been studying algae in some form or another since I was in the fifth grade, and I’ve come to learn about many aspects of their biology, chemistry, and interactions with humans – including in food, medicine, even poisonous lakes and (perhaps one day) biofuels too. Yet as I’ve grown and collected, experimented with and observed algae from around the globe, I’ve been fortunate to discover that the microscopic world has an amazing beauty to it, as well as a fascinating science. Which I find pretty cool. So I figured, it’d be pretty cool to share that with others. So here I am.
This blog is sister to two other sites I currently maintain and post online: my Instagram, @algaenthused; and my page on Experiment, a crowdsourcing website to help scientists fund their research projects (it can be found at experiment.com/algae). The former of these is filled with carefully-selected and edited photos, mostly microscopic (of algae, of course) and occasionally of normal-sized life, as well as an assortment of truly cheesy biology-related memes. (I recommend you look at them if you want some practice cringing.) The latter site is where I funded my current line of research – investigating ways to improve the use of DNA to identify species of green algae – and it is here where I directly post updates on my most recent lab work and analyses, so it’s more technical as I exercise my scientific mumbo-jumbo skills. So it’s here that I intend to bridge the gap between the two sites, combining the strict photography of Instagram with the writing from Experiment into…hopefully a somewhat-palatable medium of the two. But while this blog will be focused on algae and other elements of my microscopic adventures, I hope to make this site more personal than either of the other two, in that it will also incorporate some of my travels, more day-to-day thoughts and the life behind the science, if you will…even if my life is, at the end of the day, mostly science.
So that’s the basics of what this is supposed to be. Exactly how often I update each site, what they will eventually contain and how it all works out, I’m not so sure yet. (It’s a decently busy time of year for high school seniors, after all.) But yeah…it’s started. So that’s that for now: Post 0, Hello World. It’s Algal Ramblings.
Algal Ramblings 