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| Lake Ventina |
Lexy and I have been trying to come up with a nickname for our project. We quickly discovered a huge problem; scientists tend to be more literal than teachers. Our first idea, and my personal favorite, was “We Dig Cores” which is fabulous because it could mean both the literal, we dig cores with shovels as well as the hipster "We Love Cores". After proposing this to Scott and Paula, we were schooled in the fact that they don’t actually dig the cores, the process is to push a tube over... blah blah blah... Party poopers! Ok, not really, it’s just funny how different people think. Lexy then came up with saying “of cores” for everything, of course. It’s been an entertaining way to occupy our travel time. For the record, defining words like “corney” and “lame” to Italian is very difficult without using more slang.
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| Scott, Gianluca, and Emmanuelle building the skiff |
Scott jokingly told us to meet at Porta della Verita bright and early at 5:00am. He was actually able to keep a straight face for a whole 10 seconds. The actual start time 7:30am saw us off on the two hour ride up to Lake Ventina. I got to ride in the “squeakymobile,” and now I know why they call it Squeaky. Its a van that must date to the Romans. Let’s dive into the actual coring process now.
On the lake we used a floating platform or skiff that you can tell was designed by a scientist. By that I don’t mean high tech. It’s nothing more than a piece of plywood, two large pieces of foam covered in tarps and some straps. It looks pretty stable with three guys standing on it so kudos for coming up with this contraption. The foam pieces come off so it’s easy to transport. In the center of the deck there is a round hole cut out where the coring collecting tube will be inserted to collect the samples. There are four tie downs at each corner for anchors, and one spot for a pulley. That’s about it, a very simple machine. We also took along a larger boat with the skiff. This is where the supplies, the record keeper and lunch went.
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| Scott floating on the skiff, Gianluca and Emmanuelle coming to save him |
The first step for coring is finding the location. They paddled around for a bit looking for the deepest part of the lake. Since they’ve already cored this lake in years past, they had an idea of where to look. When they find the spot the four anchors are dropped and tied off for the skiff. It’s important for the skiff not to move so then the coring device can be dropped into the same hole. Once the skiff is anchored the larger boat is tied up to the skiff. Since we had such a large party today there wasn’t enough room for Lexy or I on either boat so Paula let us borrow her little blow up boat. This worked out well because we had the versatility of a small boat, the freedom of coming and going when we wanted, and didn’t have to worry about literally “rocking the boat.”
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| Scott and Gianluca prepping for another core, Emmanuelle getting the GPS coordinates |
The first core they took was just of the surface. The first step is to take a clear tube that is connected to a long metal rod, insert a plunge in the bottom of the clear tube then this contraption goes into the water. As it gets deeper, they are able to screw another metal rod to the top of the original one. A metal rod also goes on the top of the plunger and will also get additional rods. They then push the entire contraption into the bottom of the lake. And they do literally push. I had imagined them with a t-post hole digger you would use when digging a tree steak. Gianluca, Emmanuelle, and Scott all pushed down at the same time, as to not jar the sample. The metal rods were tapped off at certain intervals, so they were able to see when the clear tube is full of sediment. As the tube was pushed down into the sediment, the plunger was pushed up. Sounds more complicated than it is... You ever put your straw in your soda pop, put your finger over the top, then pull it out? Straw is still full. Same idea here the plunger takes the place of your finger. So again, with the rods marked off, they can tell how much sediment they’ve collected, then they pull the whole contraption up. Since this tube was clear, they were able to see the core pretty well. Since the plunger is in the tube, it was cut out. Then, sorbitol, or some chemical, I could be wrong on the name, was added to the remaining water in the top of the core. This causes the water to coagulate, making a solid layer on the top of the core. They capped off both ends, and this one was done. Now, you can imagine this is really wet sediment, so if that top hadn’t been solidified it would have settled like a milkshake which would have destroyed the "layers of time" preserved in the core.
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| Scott, Gianluca, and Emmanuelle taking a core |
I mentioned that they took a surface core first. The process for taking the testing cores is basically the same. This time they used a slightly different set up. Instead of a clear tube, they had a metal one that was slightly smaller in diameter. Everything else was the same though. Metal rods, plunger... Scott at one point was joking around with the guys, telling them if they are going to drop something, drop a tool. The livingston (the name of that metal tube device) ran the project about a thousand dollars. But the metal rods, (this made my jaw drop) cost $300 a piece! Crazy. All of a sudden even a nice pair of channel locks seems cheap. So, metal tube complete with plunger and metal rod is lowered into the center hole cut into the skiff. Once it hits the bottom of the lake, the guys all push on the rod to fill the metal tube. When full, they pull the whole contraption up again. This time however, they don’t leave the core in the tube. The pulley ratchet thing I mentioned earlier is then used to help push the core out onto another piece of tube. Remember those black PVC tubes I cleaned the other day??? The core is pushed out onto one of these, then the second half is set on top of it. The tube is then wrapped in saran wrap to help keep it from drying out. Cap it on top and bottom, mark what it is, and poof! One done!
I asked Scott how they are going to get the tube back in the original hole. This made sense, I should have realized. The boat is anchored from all four corners, so it’s not moving much at all. The hole if fixed in the boat, and the livingston basically acts like a plumb bob. The lake wasn’t very deep to begin with, I think about 4 meters.
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| Claire and Irene sealing up the core |
After they completed this second core, Lexy and I rowed to shore to let Paula and her son Nate have a shot. By lunch time the guys had already cored 11 meters, and by 2 when my half of the party was about to take off they were just starting a second core. All in all, very successful coring day!
Other than that, easy day. It’s neat to see them actually take these cores that we’ve been working with. Takes some of the mystery out of it. It’s also nice to see this project from head to toe, see how it all fits together. I can see how that could be useful in my classroom. Maybe instead of all the lab set up I tend to do for them, mixing the pH solutions, imbibing seeds, setting up certain apparatuses for lab, I should be letting them do this. Actually see a lab from head to toe. Would take a bit more training, but I really think the pay off would be worth it. Food for thought.
Alright, dinner in a bit. Thinking the spaghetti place again. That curry spaghetti was soooo good!!!
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