The Sunday Scientist by Sandy Shoup

The Sunday Scientist

Being every bit the "pointy-headed science geek" my husband tells people I am, I signed up for Dr. Shimek's online course on sand bed ecology. We students were warned in advance that since there was no textbook available on the subject, we would be reading various scientific papers and doing various experiments on our own tank's sand bed. I must admit, the first week's reading assignment was tough plowing. With my Webster's unabridged dictionary, biology dictionary and a copy of Statistics for Dummies (this is an actual book!), I did my best.

The second week of class, I got my first lab assignment. Oh goody! In order to study my sand bed, the first thing I needed to do was determine the physical parameters of the substrate. It sounded simple enough. Take a couple of core samples from the sand bed, dry them in the oven, sift them through a series of mesh screens and weigh them to determine the percentage distribution of the various grain sizes. The experiment called for one dry weight sample and one wet weight sample.

The first order of business was construction of the screens. Dr. Shimek sent us five three-inch squares of nylon mesh that ranged in size from 100 microns to 55 microns. He also sent us plans for constructing a set of stacking screens that we would make from 2" PVC. Jesse James I'm not; but I felt confident I could handle a saw, some PVC pipe and PVC cement. It turned out to be a wee-bit more difficult than I expected. Using the wrong type of cement the first time didn't help (Hey, cement is cement, right? Wrong!), so I ended up doing a lot more sanding than I would have had to if I had used the correct material the first time. I also had a small issue with my husband over using his "good screwdriver" with a mallet trying to separate PVC pieces that were stuck together. However, in the end, I did get my screens constructed, a three-foot tower of stacking screens going from largest mesh to smallest with a catch cap on the end. Voila!

Step two was the core samples. The experiment called for use of a ½ inch PVC pipe to take the core samples. One of the other students in class (who was obviously a much more talented fabricator than myself) had finished his dry weight analysis before I was even done with my screens and said he ended up with only a Dixie cup full of sand using the ½ inch PVC. This hardly seemed like a large enough sample. After all, my scale only weighed in one-gram increments, so I thought a bigger sample would provide a higher level of accuracy with my scale. So, I decided to use a 1-½ inch cylinder. (The more, the better, right?) In order to take the core sample I was supposed to push the cylinder into the sand, cover the end with one hand, pull the core sample up and cover the other end before all the sand ran out. With my tank canopy pushed back out of the way, standing on my stepstool with corer in hand, I stared down into the water. I suddenly realized that without the use of a mask and snorkel (neither of which I've owned since age ten when I lived in Guam) there was no way I was getting both my hands down to the sand bed at the same time. Over the next half hour, I made several failed attempts at one-handed sand coring. The only thing I had to show for my efforts was a soaking wet tee shirt, and a big scratch on the back of my hand where I smacked it against a rock after being attacked by an angry lawnmower blenny. ("Jack" had apparently had about enough of my mucking about in his territory.) I finally did come up with a way to get the sample by using a plastic putty knife placed at an angle in the sand near the corner. I stuffed a wad of terry cloth in the open end of the corer, and slid the other end of the corer onto the putty knife. Holding the end of the corer against the putty knife, I lifted them out of the tank without losing the sand. Ingenuity triumphs again!

The next step was baking. I made sure I conducted this part of the experiment while my husband was out of town for the weekend, just in case there was a bad smell. (You see, my last experiment with Dr. Shimek involved freeze-drying Xenia in my kitchen freezer. If you've never had the pleasure of smelling freeze-dried Xenia, lucky you! That's how I plan to make my fortune. I'm going to market Xenia as a new diet plan. Just throw a few Xenia in an uncovered jar in your freezer and I guarantee you will not open the refrigerator or freezer no matter how hungry you get!) Anyway, the core samples were baked in Pyrex dishes in the oven at 170 degrees, which is the lowest setting on my oven. Another classmate had remarked that the baking of his sediments had produced a very nice sand brick. Since my plans did not include building an adobe guesthouse in my backyard, I stirred the sediments periodically while they were baking. (That's the good news about being a little behind my other classmates. I learn from their mistakes in addition to my own.) The baking part went fine, without any undue odor (I guess Xenia is as bad as it gets!) and I was ready for the sorting.

Sorting was supposed to take about a half hour. The idea was, dump the sand into the top and gently shake the sediments allowing them to sort themselves through the five screens. Grains less than 55 microns were supposed to collect in the bottom catch cap. When I took my larger core sample, I neglected to consider the volume of sand that would fit at one time into my sorting tube. As a result of this oversight, it took me an entire, bad Sunday-morning-HBO movie and an infomercial (on a drill bit sharpener) to get my sand through the sorter. Two and a half hours of shaking left me with a sore shoulder and a cramp in my right hand.

The next step was the wet analysis. This is where the fun really began! The idea was to put distilled water into the sample, stir it up and pour it through the sorting tube. Easy, right? I made a very important discovery about my sand. I used a very fine-grained silicate sand in my reef tank. I chose it because it was the right particle size and was very inexpensive. It also does not stay suspended in water. It's been great in my tank. I didn't wash the five hundred pounds of sand before putting it in the tank and I've never had sand storms. While this tendency to settle immediately is a plus in my tank, it was impossible to pour the stuff through a screen. I put the sand and water into a glass measuring cup with a pour spout, I stirred it with a glass stir rod while trying to pour it into the sorting tube. The water ran out of the cup and through the screen and the sand came out afterwards in a big, wet clump. I made numerous attempts, all failed. During these attempts, I managed to dirty every Pyrex and Tupperware container in the house while uttering expletives the likes of which my cats have never heard. The kitchen looked like a tropical storm had hit. Wet sand, puddles and containers full of water were everywhere. I have to admit, as I sat dejectedly at the kitchen table, head in hands, I was on the verge of surrender. Luckily for me, my intellectual curiosity is only exceeded by my sheer stubbornness, so I decided to try again with a smaller core sample (I had the coring technique down by this time) and a slightly modified wet sorting procedure. Using a syringe to suck up the sand and water, I was able to squirt the mixture through each screen one at a time. My arm and shoulder, already sore from the morning of sand shaking, got quite a workout with the syringe.

By the time I was done, around 6 pm Sunday, my right arm was hanging limply at my side. I was soaked with sweat and saltwater. I'm just glad no one was around to see me (or take pictures). I had just enough time to clean up the kitchen, wash all the containers, take a quick bath and look reasonably normal by the time my husband returned home Sunday evening. I related the whole story to him, and believe it or not, he thought it was funny!

The next day I went to our online class forum to post my results and do a little whining about my trials and tribulations during the experiment. What I was not expecting, however, was to learn that Dr. Shimek expected us to have some difficulty and this too was part of the lesson. Scientific research is often difficult and time consuming. It's easy for aquarists to ask why studies haven't been done on all sorts of things that relate to our hobby. It is another thing altogether to actually invest the time, effort and money to perform the study.

Unfortunately for us, there is no financial incentive to do much research on reef aquaria. Those that manufacture and sell additives of all sorts certainly don't want anyone finding out their products are unnecessary. The processes happening in closed systems like ours are of limited value for studying natural systems, so the scientific community certainly has no great incentive. (And face it, if you were a researcher and had the choice of studying a reef aquarium in Arizona, or studying the Great Barrier Reef in Australia, where would you be?) It really is up to the aquarists. We are the ones with the vested interest. We want to have healthy, happy and natural systems full of healthy, happy animals. We can, even in our limited and sometimes clumsy "Sunday Scientist" way, contribute. While I realize that our little sand bed class probably won't be publishing any results in any scientific journal, we might just shed a little light on the processes happening in our tanks allowing us to set up healthier more stable systems.

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