Chapter Five: Peach Leaves, Denitrifying Bacteria, and Spilling Hydrogen Peroxide On My Beautiful Lips (feat. Melanie, Jeff, Jamie, Sabrina, Bryden)

Note: This blog post combines weeks five and six (the weeks of 3/6 and 3/13). I felt this was appropriate because I've done much of the same work during both weeks.

Are you any good at holding your hand out once front of you and keeping it steady? Honestly, congratulations if you are, because that right there is a skill. On a scale from 0-10, I'd say that I'm about this good at keeping my hand from shaking uncontrollably. Maybe it's because I get nervous. Maybe it's because I eat a bowl of incredibly nutrient-rich, stomach-filling Cinnamon Toast Crunch for breakfast everyday. Who knows?

All I can say is that it's probably pretty bad that I'm bad at keeping my hand steady, because these past nine days, I've started working in the Colorado Plateau Stable Isotope Laboratory (CPSIL) as an intern! The CPSIL analyzes clients' samples of anything in the environment, including water, soil, animals, etc. In reference to that, here's what I've done over the past two weeks:

The Uninteresting But Important Stuff

I started my internship at the end of a digestion cycle - that is, at the wrapping-up of one of the digestion isotope analyses. Digestion is used to break up samples so that isotopes can be more easily isolated and analyzed by putting them in hotter, more pressurized, more acidic conditions. The lab had just done analyses of large soil and plant samples, so they had tons and tons of tubes that needed to be cleaned out.

A tube in the starting stage. As can be seen, collected at the bottom of the tube lies the sediment of digested plant matter. On top of that lies about forty milliliters of acidic solution.

When the sediment is swirled around, the tube turns completely murky. Ick!

All of that solution can't be dumped in a normal sink though - it's incredibly acidic! It has to be dumped in a special hazardous waste container that gets hauled off and disposed of safely.

As can be seen, all of the acids in the container make it necessary to have a pretty strict set of regulations.

After the acids are dumped, the tubes are washed out with some normal tap water. I couldn't even tell you the amount of times I sprayed water on myself.

After washing, the tubes and caps get dumped here for drying so that they can be reused. That huge bin is only half full...

...because I couldn't finish the other half. Surprisingly, it takes a really long time to clean out a single tube.

The Seemingly Uninteresting But Actually Interesting And Important Stuff

Nearly every isotope sample in the lab is measured by running the sample through a mass spectrometer. (If you don't know how a mass spectrometer works, here's an analogy. Imagine a road with a starting line and finish line. A small car and a large truck are racing each other. If both vehicles start at the same time, and if both vehicles have the same momentum throughout the entire race, which vehicle will win the race. Pause for you to think of the answer... That's right! The small car, because momentum equals mass times velocity. A mass spectrometer is similar, except that it measures the deflection of ions based on their mass-to-charge ratio. Particles are accelerated and are put in a magnetic or electric field (in the vehicle example, the momentum), and different particles will deflect different amounts based on their mass-to-charge ratio. This isolates different ions from each other, and you can figure out how much of an isotope exists based on how many particles deflect at the isotope's known deflection amount.) The mass spectrometer requires that conditions are kept the same within the entire process so that the deflection amount isn't affected by outside conditions, but because each test is run for at least twenty-four hours, it would be nearly impossible to keep conditions the same unless you were to keep the mass spectrometer in a vacuum-sealed room (which is just ridiculous). So, as a means to combat the changing environmental effects (temperature of the room, electrical surges, etc.), standardized materials - materials that have known deflection amounts under normal conditions - are cycled in every ten or so samples in order to map out the "drift" of the machine. As there are tons of samples being run through the mass spectrometer every week, tons of standard trays - Natural Abundance Standards (NAS) - need to be made. And that's where I come in. I take little tin-foil canisters and fill them with certain amounts of materials (ranging from ground-up peach leaves to polyethylene) by scooping them into the canisters and weighing them on the scale. Once the weight is within the required range, I fold the canister into a little cube. Note that all of this is done with two forceps - it took a while to master the art.

The materials needed for standard trays, including a ton of ground-up peach leaves.

A little tin-foil canister close-up.

The station close-up.

How quaint.

The most important thing in the lab, especially when making trays, is to prevent cross-contamination - you wouldn't want multiple materials inside the canister! After every change of material, I clean the station with ethyl alcohol and wipe it with kimwipes - pretty much if tissues and printer paper had a baby.

The Interesting And Important Stuff

I got to help with grinding up a sample of fish muscle and liver. (Don't worry... the fish sample was dried up.)

The sample in its original bag.

Ground up, nice and fine.

I also got to help with culturing some denitrifying bacteria. (It's a bacteria that usually respirates with oxygen gas, but in the absence of oxygen, it takes in nitrate and puts out nitrogen gas. A client wanted to know how much nitrogen is in a soil sample, but because the nitrogen is in the form of nitrate - nitrogen bonded with three oxygens - you have to convert it into nitrogen gas.)

The streaks are where the bacteria, Pseudomonas aureofaciens, is growing.

I also got to start the process of denitrification of the soil by putting P. aureofaciens into little jars and replacing the air inside the jar with helium gas (so that there isn't any oxygen gas for the bacteria to use for respiration).

The process of putting helium gas in the jars takes a couple of hours.

Unfortunately, I didn't get to finish this process, but if I do get to continue this, I'll put it in the next blog post.

Update On My Water Research

I'll be running a simple probability test based on data from 2000-2015, evaluating the probability of the DBP levels in treated water from Lake Mary to be higher than the EPA level. As was established by Thomson et. al in 2008, I'll be using a significance level of α = 0.05.

I likely won't be able to get my water sample analyzed by April, when my AP Research project is due, but that's alright - I don't need it to get a result from my research.

This next week, besides working at the lab, I'll be doing research on Reverse Osmosis, which, in the limited amount of research that I've done on it, is looking to have lots of potential for our water treatment. Further, I'll run the significance test on the data and work on my research paper and presentation.

Shoutout to Melanie, Jeff, and Jamie for being awesome staff, as well as Sabrina and Bryden for being awesome fellow students working in the lab.

End of Chapter Five.