Science shows up in all kinds of places you might not expect. Yay! Yes, I’m a scientist. Regular readers of this blog are used to hearing about just about everything but science in this space, so the surprise and dismay at my self-identification can, and will be, forgiven. Even if it has been displayed on the sidebar since I started this blogging thing back in January. This entry, shock horror, is a science blog. It even touches on some of the things I do for a living. Really. Though I don’t do the cop thing. At least, not yet.

As I said, science shows up in all kinds of places. Prime time television drama, even. No, I mean real science. Star Trek and the SciFi channel don’t count. I’m talking about shows like CSI. But I’m willing to bet that even CSI hasn’t hit on the diatom angle yet.

Gotta give ‘em credit, though, CSI has come close. Heard of Crime Scene Insects? That’s a touring museum exhibit that’s been making the rounds for a few years now. Ever since CSI had an episode featuring forensic entomology.

For…whohahwhat? Forensic entomology. In English, that means getting crime clues using bugs. Usually flies and beetles. The kind that look upon dead bodies as free meals. There are some blowflies that can smell a corpse in the next county. And get to it with a speed that would put Superman to shame.

The short version of forensic entomology goes like this. Bug finds corpse. Lays eggs. Eggs hatch – the time to hatching is known. Larvae (maggots/grubs) emerge, and go through stages (molts – the real fancy word is instars) as they grow. The time it takes to go through each stage is known. Maggots become pupae, and finally adult bugs. Again, the time for each stage is known. Detective finds corpse, collects bugs, delivers them to science lab. Scientist identifies insect stage (egg, larva, pupa, adult) present, counts backwards. Date of death is established.

There’s more. Naturalist J.B.S. Haldane once said; “the creator had an inordinate fondness for beetles". Because scientists to date have described about 300,000 species – and there may be as many as five million of them out there. Flies are almost as bad. But for the forensic entomologist, this bad news is actually good. Because all those flies and beetles can’t all live in the same places. They divide up the world among ‘em. Some will live in cities, others in fields, still others in woodlands. And, fortunately, only a relatively small number of species will use corpses as food.

So when that scientist in the lab gets the buggy evidence from the detective, not only the life history stage but also the species of the insects is established. Presto – you not only have the date but the place of death. A corpse found in a field, but which has city bugs on it, died downtown and was dumped in that field later. If you get real lucky, the corpse will have both city and country bugs on it, so you can establish the date of the dumping.

Same kind of thing happens with diatoms. Were you wondering when I was going to get around to the diatoms? Were you wondering when I was going to tell you what a [expletive deleted] diatom is? Well, wait no more. And for those of you who got impatient, opened another browser window and did a websearch – well, this will help you sift the hits, I hope.

Diatoms are single-celled algae that literally live in glass houses. Yep, that’s right. Each one has a case made of what scientists call “amorphous silicon dioxide". Glass, near enough.

Nope, I know of no case where diatoms have gotten into stone throwing. Even though they’re all related to each other. They must be good at taking abuse and resisting temptation.

For extra credit, you can take down the scientific name of the “diatom" group. Bacillariophyceae. Sorry about your jaw. Oh – and though “algae" are usually called “plants", the diatoms are less closely related to pine trees than you are. Long story. Really long story. Another time.

Anyway. My avatar on Bloggerparty is a picture of a diatom (those of you who came over here from my Wordpress site are used to seeing an amoeba, so take a glance to the right of this page). They come in a wide range of sizes and shapes – triangular ones are unusual, which is why I use it for my avatar. You already know I’m weird, so I may as well identify myself with weird icons.

Now about that glass house. Just in case you thought it was plain glass like the windows in your house. ‘Tain’t so. The glass cell wall of your average diatom has got pores and slits and struts and spikes and all kind of things in and on it. And practically all of these ornaments are too small to see even with the best light microscopes. You need an electron microscope to see them. If a company figures out how to make chips and circuits that small, with the reliabile reproduction of the pattern that one sees in diatom cells, you’ll have laptops the size of your little fingernail. And somebody’s going to make a whole lot of money.

Don’t believe me? Don't think the diatom ornaments are really that small? Have a look at these pictures. For what it’s worth, I didn’t swipe them off the net; they’re all mine. The first one is of a living cell. Looks pretty plain, doesn’t it? The second one is the same kind of cell, with all the living parts removed – I use a bath of plain old household chlorine bleach, followed by 3% hydrogen peroxide, to accomplish this. The third one is once again the same, seen in the scanning electron microscope.

Then there’s the fourth one. Similar-looking diatom in the light microscope, but completely different in the scanning electron microscope. And that’s what leads to forensic diatomology.

Because, while there aren’t quite so many diatoms as there are beetles, there are still a lot of ‘em out there. Some 20,000 species or more have been described – who knows how many more remain to be found (100,000 maybe?), but new ones appear in the scientific literature constantly, in journals you’ve never heard of like Diatom Research. Each diatom lives in a glass house, and each species’s glass house is ornamented differently from every other ones.

And, just like with the beetles and flies, not every species of diatom can live in the same place at the same time as every other one. They divide the environment up among ‘em. Some species live in freshwater, some in salt. Some prefer cold temperatures, some warm. Some freshwater diatoms prefer more acidic waters, some more alkaline. Some float in the water, others are attached to surfaces. And on and on it goes. Right into the crime lab.

Say you find a body floating in the bay. Did that person drown? If so, there will likely be diatoms in the lung tissues. If the person was drowned, did it happen in the bay, or was the body washed down from the river? The diatoms in the lungs will tell you. Likewise, if the body was discovered in an acid lake, but the diatoms are of a type found only in alkaline water, you get the idea that somebody, sometime, moved the corpse.

It may even be possible to say when the drowning occurred, because the kinds of diatoms present in the water changes with the seasons, sometimes (especially during spring and fall) very quickly. If the body was found in May, but the diatoms in the lungs were of types that normally are found in April, you’ve established an approximate date of death. Which might be difficult to come by with any precision by any other means, if the body has really been sitting around for that long.

Some little while ago now, I threatened to write a murder mystery based on the exploits of the curator of ferns in a major herbarium. I didn’t mention that some of the clues leading to the identification of the murderer were to come from an analysis of the herbarium beetles that had started to dine out on the victim – who had been stuffed into one of the dried-plant cases.

Guess maybe the second novel in that series will have to feature a drowning, and the microscopical investigations of the museum’s curator of diatoms.

Suppose CSI will buy the screenplay? Nah …

   - O Ceallaigh

Copyright © 2006 Felloffatruck Publications. All wrongs deplored.

All opinions are mine as a private citizen.