Looking Closely

Written by Anna Cates on Tuesday, December 06, 2016 at 4:05 PM

Scientists look through microscopes. This is certainly something I believed before I took any science classes. I thought they must peer at cell structures and tiny organisms and minerals for a portion of every day, say at least 25%. I was relieved to learn you can do a lot of science without even a magnifying glass, especially in agriculture where a lot of what we’re interested in- plants, water, people, eating- is definitely visible to the naked eye. I had always found it difficult to focus through microscopes, and had a hard time picking out cell structures in high school biology.

However, recently I’ve gotten involved with counting tiny organisms less than 1 mm long. I’m trying to figure out what kinds of critters are part of the food web based on decomposing plant litter. Microbes live by breaking down plant litter, and other organisms, like mites and collembola, eat the microbes. In order to get a picture of who’s involved in decomposition, we are characterizing the microbial community and also the mites and collembola. 

So last fall I found myself nervously sitting down at an actual microscope. I had to twiddle all the knobs a few times to figure out where to turn the light up and how to focus in and out. How will I ever distinguish little blobby mites, which look like ticks, from blobby soil aggregates, I worried? Don’t collembola pretty much look like shards of leaves? I got some training from an undergrad employee in Claudio Gratton’s lab, who I have seen spend days on end in front of these microscopes identifying insects, arthropods and organisms of all sorts. She pointed out a few examples. I looked through the scope behind her and was thrilled to see yes, there was the characteristic “springtail” of a collembolan, tucked underneath the segmented body. And there were the tear-shaped bodies of mites with little legs.

She left me on my own to slowly pan through a petri dish of soil, litter, and critters floating in ethanol.  Although the scene was crowded, again and again these creatures would jump to my attention. The symmetry of the mites’ bodies differentiated them from the irregular, translucent sand particles. There was something instantly recognizable as a form of life in the way the collembola curled into little C’s. Sometimes I’d run across an ant, or a fly, or a mystery (to me) and I’d ask my expert at the scope down the bench to take a look. She recognized all of them easily- isopod, fly larvae, bee.

Your eye can become trained to these patterns so quickly. It’s the same with a botanist who can identify a tree based on the bark in winter, or the birder who knows the swoop of an individual raptor, or the dairyman who could tell you something about health and milk production from a glance at a cow. On top of that, our eyes begin to recognize more complex patterns- familiar ecosystems like cottonwoods, willows and streams or processes like growth, flowering, and senescence. Training to recognize deviations from these patterns is where the rubber hits the road in terms of interesting scientific questions or innovative land management practices....at least, that’s what I tell myself while I put in time at the scope. That, and that I look like a real scientist. 

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