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16 November, 2004

Light levels and support from town!

Temperature: 17*F

Location: Lake Hoare

Not too long ago, I had a ďlive chatĒ over the internet with my school in NH and anyone who was listening in during the broadcast. During this chat, we discussed how important the support teams are to the scientists here in Antarctica. It truly would be very difficult for most of this research to be done without the never ending support in McMurdo. There are mechanics to fix engines, computer specialists to tackle computer glitches, welders, doctors, chefs, builders, and pilots just to name a few. Itís not that the science could not get done without the support, itís just that it would be infinitely more difficult.

Yesterday, we had a dive compressor delivered from town so that we can refill our dive tanks. While we were refilling the tanks, we noticed a significant air leak from the machine. We were pumping almost as much air back out into the environment as we were putting into our tanks! We located the source of the leak and attempted to first stop the leak by tightening the bolt. Unfortunately, this decision caused the bolt to be sheered right off the machine. Without a working compressor, no diving could get done. We had enough air left in the tanks to last for three dives; depending on depth and longevity. The tanks we pull our air from for surface supply diving are huge cylinders, not regular sized dive tanks. We called the Mechanical Equipment Center, or MEC, back in McMurdo and asked for assistance.

We took digital pictures of the problem and emerald the photos to the MEC building. Within a few hours, they had a mechanic on a helicopter coming to help. Luckily for us, the problem was easily remedied and we got back to diving!

During my dive today, I took light level measurements of the water column below Lake Hoare. I took a light meter which was attached to a super long cable down under the ice with me. Once under the ice, I swam straight out from the dive hole taking measurements every 10 meters. In designated areas, I also descended to the bottom, taking light measurements every 7-10 feet. The lake, in the area where we were sampling, is only about 50 feet deep. I quite enjoyed being part of the actual data collection.

Ian then dove and collected sediment samples to analyze in the lab. Ian is interested in the photosynthetic levels of the cyanobacteria that live in these lakes. Photosynthetic organisms need light in order to photosynthesize. Ian and Kay then took the collected samples and the known light measurement values back to the lab.

1. Me tending the dive line for Ian; I am talking to him on the handset as he dives!

2. Dive tank for the back up diver; notice there are two regulators attached.

3. The "polar haven" is our dive hut on the ice. A considerable amount of our gear and the compressor are stored in this hut. It's also a place to get in out of the wind and cold.

4. A close up view of the air intake valve. The hose is connected to the compressor which forces air from the environment into our storage air tanks.

5. The "dive box." The white outlined square on the top left includes the communications cables, the power switches, and the speaker. This allows us to communicate from below ice to the surface and vice versa. The bottom left contains the hoses that go to the tanks; the knobs allow the amount of air coming out of the tanks to be controlled. The bottom right is the guage indicating the air pressure the diver is breathing through. The top right is the neumo guage which allows us to spot check the depth of the diver.

6. The dive compressor. The pointed end of the axe is resting on the broken part.

7. The broken part!

8. Back in the lab, Ian zaps the algal matt with an electrode to measure photosynthesis.

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