MacGyver-ed Experiments

1 11 2012

If MacGyver were a marine biologist, I try to imagine what complicated experiments he could create using a roll of duct-tape, a shoelace, and an empty Coca-Cola bottle he found on the beach.  I have a strange imagination.

I tried to channel some inner-MacGyver while working on setting up my experiment.  Remember, I’m trying to figure out how close together two abalones must be in order to successfully reproduce.  I had a rough idea of how the experiment should go in my head, but sometimes it’s hard to connect what I envision with reality.

Tide pool used in experiments on San Nicolas Island (B. Blaud)

So here’s what I initially pictured: I would let a sperm cloud build up for five minutes using a controlled release from an IV bag, commandeered from a local hospital by sources unnamed (love you big sis!!!), then I would release the eggs all at once and collect water samples.  This seemed pretty simple and straightforward in my head until my advisor, Glenn VanBlaricom, asked how I would collect the samples.  We brainstormed different systems, one involving placing 10 people in the tide pool with bottles, scooping up water samples, and another with sampling tubes rigged onto a frame that would be anchored to the bottom of the tide pool.

Sampling bottles (B. Blaud)

What we ended up doing was something in between the two ideas.  I thought it would be useful if the sampling bottles functioned similar to a Niskin bottle, which is used in oceanography to take water samples from different depths.  It is hollow and open on both ends, which allows water to flow through.  Water samples are collected at a desired depth by triggering a mechanism that allows the stoppers on either end of the tube to close.  These bottles range from a couple hundred to several thousand dollars, are much larger than I need for my samples, and are entirely out of my budget of $52.37 (all that I had in my checking account at the time).

With the invaluable help from Julia Eggers, I was able to create unique sampling bottles using PVC pipes, racquetballs, surgical tubing, and zip-ties.  Eggers and I spent a couple afternoons scouring the local hardware stores and harassing poor Home Depot employees to figure out how we could make this contraption hold water.  After collecting supplies, we would run back to the shop at school and experiment with different designs.  Through trial and error, we came up with something pretty darn cool and simple.  To make them in bulk (I needed 40 of them), I got all the supplies together, bought pizza and beer, and invited friends over for an assembly party.  Ah, what my friends won’t do for a free beer…

Chris Yates with a water sample that has visible egg- and sperm-size particles (B. Blaud

To get the whole thing to work, the simplest plan was to place actual people into the tide pool at the time of the experiment, and run it like I had envisioned.  We had a couple other experiences in the trial and error process that were fairly painful.  To get an idea of how the experiment would go, VanBlaricom and I headed out to practice in a tide pool.  We set up an IV bag with the fake-abalone sperm and put the fake-abalone eggs into the water using a turkey baster.  One problem we didn’t anticipate: the particles floated – and so while we watched, literally $1,000 floated away into the sunset!  I could have cried, and maybe did a little.  All my research online indicated they would be neutrally buoyant in the water, but we totally discounted needing a dispersant, something that would break the surface tension of water and allow the particles to enter the water column.  Dawn detergent to the rescue!  The next day, we headed back to the same tide pool with Dawn and another batch of particles, and this time we were successful.

IV bags, the right one containing sperm-size particles (B. Blaud)

For the short experiment practicing to see how the particles would react and brainstorming how we would choreograph the entire experimental run, the IV bag worked great!  Unfortunately, in the extended, real runs, it clogged (another $1,000 floats off into the sunset with no data collected – more tears shed, and not the last).  I used swiss army knife to remove the drip chamber where the clog was occurring and attached the tube directly into the bag with duct tape (see, I AM like MacGyver, solving the world’s problems with a piece of duct-tape!).

I set up a tripod to hold the IV bag, filled it with fake-abalone sperm mixed with seawater and Dawn detergent, and let it release for 5-minutes before releasing the eggs.  Everyone had his or her own location, a set distance from the egg release location and collected water samples at precisely 0, 15, 30, 60, and 300 seconds from the time the eggs were released.  The choreography was something else that was worked out through trial and error, but after several runs (some successes, some failures), we got a good system worked out.

And thus, we completed six successful runs of simulated spawning experiments, providing me with roughly 684 samples to run process.

Next up, from the field to the lab…



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