Jun 042014

Common House Centipede (Scutigera coleoptrata) Click image for source.

My daughter slept on the couch last night because there was a “giant centipede” in her room. A search on “giant centipede” turns up exotic beauties like the fabulous foot-long Scolopendra gigantea, which eats mice, snakes, lizards, birds and frogs and has even figured out how to catch bats by dangling from cave ceilings .  I doubt that my daughter’s centipede was really a giant–she only needed one hand to show me how big it was.  But it’s another reminder, if we need one, that “nature” is not off in the woods somewhere, and you don’t have to paddle to it, or ride there on an ATV.  It is under the floorboards and between the threads of our sheets.  It’s us, and it’s all over us.  As science writers like to remind us, our own skins are a fertile savannah to the microbes and mites that browse in its moist valleys and fungal thickets.  Our intestines are as lush and biologically diverse as a jungle, an Amazon you can carry around.

Too often, though, we think of nature as something that had better not be scrabbling up the leg of the bed.  It belongs in certain places, and we do like to put things where they belong.  The urge to sort things, to put them in their place, is strong in us and features prominently in lists of human universals.  When things are in the “wrong” place, we tend to not see them properly, or to not see them at all.  Take the contents of any contemporary art museum and put them out by the side of the road.  I’m pretty sure some of the artwork will still be there the next day; and some of it will probably sit there long enough to be hauled away with the trash on Wednesday morning.  Leaving aside the likelihood that the landfill is the right place for some of it, this is a small failure of perception, one that is so common and familiar that we design our public spaces to allow for it.  We have trouble seeing the art, even when it is in front of our eyes.  So, we label the art, or lift it off the ground on a slab of stone, or we build places like museums and galleries where the right kind of seeing and thinking is gently encouraged.

Seeing “nature” is almost as hard as seeing “art”. To make it possible to notice nature, we set some of it aside in special spots.  These are our sanctuaries and conservation zones: places where we can look at what would be here if we were not.  We choose a patch of ground, or pool of water–often, I’m sorry to say, one that nobody wants for anything else–and we do with it something that does not come naturally to us, something that is not “in our nature”: we leave it alone.  We just leave it to itself, so that we can go there once in a while, and look at it to see what things are like when we are not around.  Except that we are around, of course, stealthily watching.  We are there and not there at the same time.  This gives us a feeling we find so agreeable that we are willing to tax one other to pay for it all: the boardwalks and the picnic tables, the bilingual signs warning us not to interfere with it in any way.

A marsh in the Mer Bleue Conservation Area

A marsh in the Mer Bleue Conservation Area

For a couple of years, I’ve been going to one of those places as often as I can.  It is the Mer Bleue Bog, a patch of subarctic peatland inside Ottawa’s city limits.  At one time, the Ottawa River ran directly through it, but then the course of the river changed, leaving it hydrologically isolated, fed only by rainwater. For about 8,400 years, sphagnum moss has been accumulating there, to a depth of 6 metres in some places.  It is an unbroken link to the end of the last ice age, and although the city and its commercial sprawl are not far away, it has an eerie–I was about to say “unnatural”–calm that seems to startle its many visitors into speaking very quietly, as if they were in a church.

There is still some open water attached to the bog, including a cattail marsh where I collect samples to look at under the microscope.  It is what lake researchers–“limnologists”–call a “dystrophic lake.” The water is low in nutrients, highly acidic and steeped in humus.  It is the colour of a weak tea, one that happens to be filled with the most wonderful algae, ciliates and amoebae.

The chemistry of the water, and the isolation of the entire system, give it a distinctive microlife, quite different from anything in the other lakes and rivers around here.  It is much greener, for one thing.  Perhaps because it is so poor in available nutrients, many of the organisms here make their own food by photosynthesis.  In this water, I’ve found a surprising diversity of protists, including many that don’t turn up in my usual samples,and a few that have never been described before.

A new testate amoeba in the genus Arcella.

A new testate amoeba in the genus Arcella.

Some are different enough to deserve new names of their own. The most recent novelty to turn up in my jars is a testate amoeba of the genus Arcella, a creature that lives in a rather pretty proteinaceous shell.  This one resembles an amoeba described in 1918 by Playfair, Arcella costata var. angulosa.  However, it is distinct enough from anything previously described that, in the opinion of Arcella expert Ralf Meisterfeld (in personal communication), it is “certainly a new species.”



Arcella ventral view 1

Ventral view showing crenulated pseudostome.

The  main feature that sets it apart is the shape of the aperture at the bottom of the shell.  This “pseudostome” (“false mouth”) is an opening in the shell through which the amoeba extends its pseudopods.  In most Arcella it is smooth and round, but in these guys it has a frilly, “crenulated” shape, like a malformed flower. I wonder if this is a strictly local variation, or something that is found elsewhere in the world?  I would like to think it arose locally in the Mer Bleue population, perhaps because of its isolation from the surrounding waters; however, it is likely that the feature is found in many other populations, but has rarely been recorded. This line of thought risks reanimating the perpetual debate about whether microbial species have a discernible biogeography, as lemurs and wombats do. I’ll leave that alone for now, but it deserves a post of its own.

In the meantime, here’s some video of  this little jewel: