Photosynthesis is key for the organisms living here. Without it, these mats won't survive. The light levels fluctuate greatly between lakes, ice thickness, amount of sand on the lake surface, time of day, cloud cover, and season - don't forget.... it's totally dark here for several months each winter! These organisms are able to thrive on incredibly low levels of light. Part of our task is to measure how much light penetrates the ice and reaches the mats at various depths, as well as what wavelengths of light are reaching which depths.
This is the LiCor; it is a light sensor. This sensor measures light available in the photosynthetic spectrum. Basically, this is the same light, visible light, that you and I use. This picture was taken in shallow water at Lake Hoare. Compare it to the next photo!
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Here's the same LiCor sensor at about 34 feet in Lake Fryxell! Can you see it? It's easiest to focus on the square white top. It is sitting just in the sulfide cloud layer. I took this photo on one of my missions to retrieve the LiCor. I have retrieved the LiCor several times so that we can download the data it has collected and then set it back out. It collects a light reading every minute. Luckily, we have a line going to the LiCor when it is deployed by itself (it's usually near Hal - Hal has a cable going to him from the surface, so you can't lose him!) - otherwise - it would be quite hard to find! I told you these mats can survive on incredibly low levels of light!
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We also have the trios deployed. This is also a light sensor, but it measures light levels across the entire spectrum from Ultraviolet to infrared wavelengths. By using this sensor, we can determine which wavelengths of light are reaching the different depths, thus which wavelength(s) of light the existing mats in the region are likely to be using. Today, I took the trios to all different levels in the lake; from right up close to the underside of the ice (but not touching!) to the very bottom. I paused at different depths in the water column so Ian and Kay could get a sensor reading. Then, I brought the trios out - it's job is done for now!
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Just a fun look down the hole!
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We are getting quite a pile of ice chips from the ice we chip out of the hole each day!
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I dare you to cross the moat! Careful - it's an adventure! Can you see the camp just on the shore across the moat (it looks like a tiny horizontal black line). The moat is starting to feel like crossing one of those wooden bridges where all the planks collapse behind you. If it starts to crack... run! Of course getting the ATV across is becoming more of an adventure as well. Drive really "fast" (fast on the moat is relative!) so you don't crash through the ice!
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The ATV in its "garage" (parked over a drip pan) with the rough ice behind.
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Today, Kay collected a core sample. This is Kay back at the lab conducting an analysis. The probe is measuring hydrogen sulfide. The yellow layer is oil which was added to the top of the sample to try to capture the hydrogen sulfide that is escaping from the mat so it can be measured. Pretty cool huh?
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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.