17 January, 1997
Remember that I mentioned the stream team yesterday? There are two volunteers that are undergraduate students who work on collecting water samples from the streams when they are flowing. The PI for stream ecology in the LTER is here and during the discussion of stream flow and seasonal impact on the ecosystem in the lake, an offer came my way to go up to the Taylor Glacier along with the National Geographic photographer who is doing an arcticle on the dry valleys. Of course, I jumped at the chance since we will be gone only for an hour. The helo ride was only 5 minutes, and saved us a 4 hour walk. At the leading edge of the Taylor Glacier is blood falls, an ice flow loaded with iron deposits looking very much like a red rust. There are two streams flowing with a fairly large volume of water. On each of the two streams there is a wyer build with a sand bags and rock dam on either side. Instrumentation is in place to measure stream flow rates and volumes. Without the streams flowing, the lake would have no nutrients or minerals added. The stream team does a wide variety of water chemistry similar to the limno team who test only lake water.
There is a ridge between the two lobes of Lake Bonney. The passage between the two lake lobes is about 100 feet wide at the present time, but has a recorded width measurement made by Scott and Taylor when they discovered this valley in the early 1900's, of only 17 feet. This is one piece of evidence that the lake level is rising. There are other pieces of evidence that the climate is warming causing more glacier melt. The helicopter landing pad used to be some distance from the lake edge. It is now so close to the edge of the lake that the tail of the helo is over the water and passengers are likely to get wet when disembarking. The passage is formed by two land masses that are not directly opposite from each other. It is thought that this is evidence of river erosion action since they are offset rather than directly opposite each other as they might be if the forces were only glacial. What do you think?
Another debate is also being discussed about the age of these valleys. It is thought that Antarctica broke away as a land mass and arrived at its current position 28 million years ago. One theory says that this valley is 17 million years old based on the condition of the volcanic basalt that has not been rained on and therefore has not been changed into a glassy form. It looks like newly erupted rock. It is dated with the last eruptions of volcanoes here. Others think that the 17 million year age is wrong based on marine diatoms found at the tops of some of the transcontinental mountains thought to be only 3 million years of age. They feel that the Ross Ice Shelf formed and glacier action pushed the marine diatoms up the mountains. What to you think happened? Why is it important to understand the processes in the past?
I plan to walk back to the Lake Hoare camp tomorrow. I will get to look at the interface of several glaciers with both lakes and with a dry part of the valley. There is a New Zealand camp along the way. The "kiwis" as they are called, have cut a tunnel into one of the glaciers so we plan to look for it and even venture into the tunnel as far as we can see. This is one time that a flashlight might be needed here.
I spent 6 hours in the lab filtering water samples as part of the limno testing. We finished at about 9:30 p.m. and will have a gormet dinner now!
Send me some comments! What do you think about the research being done here in the Taylor Valley? How is this information of value to you? Lakeside, I am waiting to hear from you. More later
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