Mrs. Happ's class wrote:
Dear Dr. Sokol,These are some really good questions about glaciers. This is exactly what glaciologists are trying to figure out. I have been learning that there are many different kinds of glaciers. The ones I see in the dry valleys are relatively small alpine and piedmont glaciers. They advance from the mountains down into the Dry Valleys relatively slowly (my guess is a few feet a year). These glaciers seem to be melting or ablating as quickly as they are advancing, so they don't seem like they move very much. This is quite a contrast with the only glacier I've seen in the northern hemisphere, the Mendenhall Glacier in Juneau, Alaska. I have read that the Mendenhall Glacier has been retreating hundreds of feet each year.
Thank you so much for your wonderful answers – we are learning lots and now we have more questions about the glaciers. First of all, we were wondering if you have noticed any changes in the glaciers since you have been going to Antarctica. Is there any melting or perhaps more melting now than before? If so, does it change the amount of organisms you find when you are out collecting things?
We do anticipate that these glaciers will melt more in the near future, and we are currently working on experiments to figure out how increases in melt water in the Dry Valleys will affect the soil biology. There is some evidence that melting has increased because the lake levels are rising in Taylor Valley, and the lakes get their water from glacial melt.
The glaciers that glaciologists seem to be most interested in are outlet glaciers. These are very large glaciers that are essentially very large and very slow moving rivers of ice that "drain" the West and East Antarctic Ice Sheets. The rate at which these glaciers "flow" and melt and calve into the ocean plays a big role in determining how much ice will remain in Antarcitca, how high sea levels will rise, and how salty the ocean will be as the global climate warms. Pine Island Glacier (known as PIG) is an outlet glacier for the West Antarctic Ice Sheet that scientists are studying this year. This glacier moves very fast (meters a day), and scientists are studying it to figure out what types of environmental factors influence the mass-balance of ice in Antarctica. I believe they are focusing on how changes in ocean water temperature and salinity increase melting of the glacier where it meets the ocean.
Here are some links about Pine Island Glacier:
Finally, we learned about the snow goggles the Inuit designed a long time ago because the sun was so bright and wondered if you had to protect your eyes with more than just regular sunglasses when you are outside. We hope you have a good week.We have the same challenge in Antarctica. We have to wear sunglasses all the time when we are outside because the sun is always in the sky. Ozone depletion is particularly bad over Antarctica and more of the harmful UV rays make it through the atmosphere and to our eyes. UV radiation is what causes snow blindness by basically giving your eyes a sunburn, so we have to make sure our sunglasses can block UV radiation -- knock-off gas station sunglasses don't cut it, but I just use a nice pair of polarized sunglasses with UV protection. We have to be really careful when flying or hiking over ice and snow because the shiny surfaces reflect all of that UV radiation back at us.
Thanks for all of the really great questions!