Tuesday, February 5, 2013

Answers for Mrs. Happ's class

Mrs. Happ's class wrote:
Dear Dr. Sokol,
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?
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.

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!

Monday, February 4, 2013

Answers for Mrs. Fridson and the first grade at Hillel Day School

Mrs. Fridson and the first graders at Hillel Day School asked:
Dear Dr. Sokol,
We are so happy to be able to talk with you again this year! We know that you are on your way back home but we are certain you could answer a question or two about your experience. 
1. Is it comfy wearing all of that snow gear?
The cold weather clothes are comfortable, but they are heavy and restrict our movement and make it difficult to hike long distances (or touch your toes).  A lot of our work in the McMurdo Dry Valleys involves hiking from site to site collecting samples.  We usually wear the really warm clothes when we are standing around collecting samples or waiting for scientific instruments to make readings.  Then we pack our warm clothes into backpacks before hiking to the next spot so we don't overheat.
2. How far away is the sun from Antarctica?
The short answer is approximately 93 million miles, but the distance changes with the time of year.

The long answer is this:  According to Google, the sun is approximately 93,020,000 miles away from the Earth, on average.  The distance between your location on the Earth and the sun will change as the earth rotates -- you're closer to the sun during the day than at night.  At the south pole (or north pole) your distance from the sun doesn't change as the earth spins, because you are at the axis.  You can test this out be shining a flashlight at a globe.  Pick a spot on the globe that is light, then spin the globe until that spot is in the dark.  Is it farther away from the light?  Now look at the south pole.  If you spin the globe does the south pole's distance from the light change?

The answer get's even more complicated, however, because the earth's axis is tilted and the orbit around the sun is not a perfect circle.  In July, the earth is at its farthest point from the sun in its orbit around the sun.  However, this is when it is summer time in Michigan because the earth's axis is tilted so that the northern hemisphere of the earth receives more sun light and is warmer than the southern hemisphere.  At this time the north pole is closer to the sun than the south pole.  In January, the earth is closest to the sun.  During this time of year (winter in Michigan) the earth's axis is tilted so that the south pole is closer to the sun than the north pole, and the southern hemisphere receives more sunlight and is warmer than the northern hemisphere.
3. How do penguins survive the bitter cold?
This is a really good question that scientists are still studying.  My guess is that it is a combination of physiology and behavior. Penguins, like other birds, produce heat by metabolizing energy that is stored as fat.  They eat lots of fish during the summer, build up their fat, and use that energy to keep warm over the winter.  They are also well insulated with feathers and fat, so the insulation helps keep them from losing heat.  Some penguins live in large colonies and they huddle together to keep each other warm during the winter.  Many penguins together create heat and insulation and shelter form the wind more efficiently than a single penguin.  I read that they will take turns warming up in the middle of the group, and then stand on the edge of the group while other penguins warm up in the middle.
4. How much food and what kind of food do you eat?
At McMurdo station there is a cafeteria, probably similar to your school cafeteria, where we get breakfast, lunch and dinner.  Most of the food we get is preserved in cans, dried, or some sort of non-perishable snack food.  For example, we can have eggs at breakfast, but they are often reconstituted from dehydrated or frozen eggs.  They make okay scrambled eggs if you eat them fast enough and don't think about it.  The cooks who work in the cafeteria make really excellent baked goods.  We usually have fresh bread and/or cake or cobbler with dinner.

Out at field camps we cook our own food.  We use the same ingredients that the cooks use in the cafeteria.  Our favorite things to cook this season were frozen halibut steaks, frittatas, and pizza.  We made some really good homemade pizzas with various canned and frozen goods.
5. Do you enjoy the type of experiments you do?
Good question.  I enjoy many aspects of the science we do.  Sometimes it is a lot of work, but we learn really interesting things and get to see really interesting places.  Many of the experiments I work on are considered long-term experiments, which means they run for a long time.  Some of the experiments have been going for 10, 15, or 20 years.  This is because changes in ecosystems can happen over very long time periods.

For example, there are some experiments where we have been adding different types of nutrients to plots of soil in the Dry Valleys to see which types of nutrients the bacteria and microscopic animals in the soil need to grow.  In order to understand how these soil organisms respond to nutrients, especially in really cold dry places, we need to monitor the plots for a long time.  Part of this is because we want to know if the organisms respond to nutrients the same way in dry years and wet years, and warm years and cold years, and the weather is not very predictable in Antarctica.  I have been working on this experiment for 2 years and it is really interesting to be able to go out to the sites and see differences in measurements of how the soil organisms are responding to the nutrients, and I get to experience how cold (or warm) the sites actually are, first hand.
6. If you have sunlight all of the time, how do you sleep?
Sunlight at nighttime hasn't kept me awake.  I guess if I work hard enough, I'm tired enough to fall asleep.