When we melted this new dive hole, we used two hotsy systems and two generators. The generator powers the hotsy. A hotsy is the device that contains glycol in a closed tube system that is heated. This system has a "hot finger" on the end to melt efficiently. All of these things together allowed us to make this great dive hole in 24 hours - that's fast! In order to fuel the equipment, we had several 55 gallon drums of fuel. These drums have been sitting beside the dive hole since we started diving here. Today, a helicopter came to take the fuel from the ice over to camp and back to town; we don't need it anymore. This meant, however, that we had to disassemble all the dive gear and secure the tent for a helicopter to land beside. This took most of the morning. The dive hole area seems much bigger now with all the drums gone!
Ian dove first to try and scout out the next location for Hal, and to collect some core samples. He pulled up a couple of nice cores! Then Peter dove to start laying out a transect line for us to sample along. As I mentioned previously, it is fairly dark in Lake Fryxell and the cloud within the sulfide zone makes it difficult to navigate. So, laying the transect line helps us to stay on course. We will collect more sediment cores, as well as water samples starting tomorrow. By the time all this work was done, it was late in the afternoon and Kay needed more time to prepare Hal properly for his new launch, so we decided to play it safe and call it a day in order to get an earlier start tomorrow.
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Peter (in red) and Ian check out the core samples that Ian just brought up from below the sulfide zone.
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(This picture and note, I posted yesterday - it is here again as a reminder)
First, notice the multiple layers of growth on the top. Then there is a layer of sand and gravel. This sand and gravel gets to the bottom by "dumping" through the ice. As the sand and gravel blows onto the lake, the sun heats it up and is starts to sink into the ice. The ice, in general, ablates (is removed) from the surface and refrozen below, so there is a basic upward movement of the ice. What this means is that any particles in the ice from the surface, move deeper into the ice. Any particles in the ice from below, move higher into the ice. The sand that originally blew onto the surface reaches the bottom of the ice, and then "dumps" to the bottom. Below the gravel in this core sample there is a black layer, then another layer of mat. The lower mat is decomposing. The black layer is the sulfur which is produced through the decomposition of the lower layer and is diffusing upward into the higher mats and being used in photosynthesis. Pretty "smart" huh?
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Check this out - this is cool! This is the core sample that Kay picked up yesterday. Today, he created an overlay of the sulfide data readings. Start at the top.... This high sulfide reading was found in the water, just above the mat. It is possible that the free living sulfur bacteria just above the mat are causing this higher level of sulfide. It may also be that there is some decomposition in the upper mat that gives off sulfide into the water. At any rate, as the probes go through the upper mat, sulfide levels drop. This is because the bacteria are using the sulfide for photosynthesis! Then, as you continue below the upper mat layer, sulfide levels start to increase again. This is because the lower, decomposing mat, is releasing sulfide. So as the probe gets closer to that layer, it can measure that the sulfide levels increase. Then levels drops off again below the lower layer. Cool data!
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One advantage of the moat melting is that we can just walk down to the shore of the lake to collect water for drinking and cooking. It always amazes me that the edge ice is strong enough to hold people. We wouldn't think of stepping on ice this thin back home. Here's Ian - "on the edge" collecting water.
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Kay also collects some water at the moat edge. Look at how much of the moat has melted - yikes!
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This is the Commonwealth Glacier on the other end of Lake Fryxell. Basically, Lake Fryxell has the Canada Glacier on one end and the Commonwealth Glacier on the other end. Both are beautiful!
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•Ms. Ellwood - rellwood@sau50.k12.nh.us
Questions may be posted with the answers on the page below.
• Questions and answers about the trip.
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Antarctica 2006 
Antarctica 2006 homepage.