Stoichiometry

This morning, Katie and I flew to the Lake Bonney basin for another two days of field work.
While we are here, we will be working on a project that will tell us how the soil and soil organisms respond to nutrients added to the soil.

There are three main elements that are very important for life everywhere: carbon, nitrogen, and phosphorus. These nutrients are important for all organisms to grow and live. If one of these elements is in short supply, organisms cannot continue to grow. So, the amount of nutrients in the soil can be limiting to life. We want to know which of these elements are limiting to life in the dry valleys.

We have set up areas where we add carbon, nitrogen, and phosphorus to the soil. Each year, we add more of the nutrients and measure how the microbes and invertebrates living in the soil respond to the additions. We add the nutrients by dissolving sugar and salt in water, then pouring the water over the plots. Some plots get sugar water (for carbon), some get water with nitrogen or phosphorus salt added, and some get both sugar and salt. In this photo, Breana is adding some nutrient water to one of the plots.

We use the plastic cone to prevent the wind from blowing the water away before it reaches the ground. Or, you can be like Uffe and wear the cones as a hula skirt:
After we add the nutrients, we measure respiration to see how active the microbes are. We also measure the amount of nematodes in the soil and how the soil chemistry changes after the nutrients are added.

We've been working on this project for many years. So far, we have learned that carbon is most limiting to life in the dry valleys. Carbon in the soil mostly comes from photosynthesis by plants. Plants are able to take carbon from the air (as carbon dioxide) and turn it into forms usable by soil organisms. Because Antarctica is so cold and dry, there are not a lot of plants. We only have some mosses and algae that can photosynthesize, and they are only found near sources of water. Because there's not a lot of photosynthesis, there is not a lot of carbon added naturally to the soil. So, carbon is often the limiting nutrient in the dry valley soils, which is why we notice the biggest response in the activity of the organisms when we add carbon.

Nitrogen and phosphorus may also become limiting in the soil, if there is enough carbon for organisms to use. That is why we look at all three of the nutrients. We want to know how increases in all three nutrients might influence soil organisms. Which nutrient is most limiting might not be the same everywhere in the dry valleys, since the different areas have different geology. Hopefully this project will be able to tell us which nutrients are limiting in the different areas.

Katie and I are only at Bonney through tomorrow, then it's back to McMurdo to process our soil samples that we collect here. Hopefully, the final member of our team will arrive tomorrow. Ross's flight should be arriving tomorrow afternoon as we're returning from the field. Let's all hope that the good weather continues!

Happy New Year!

It is 2009 down here at McMurdo!

We returned from the field on New Year's Eve. We quickly unpacked and took care of all of our samples for the evening. Then, we were ready to celebrate the holiday!

The new year starts for us 18 hours earlier than the east coast of the U.S., so we celebrated New Years Day before most of the U.S. woke up to New Years Eve. Here's Breana (one of the postdocs working with us down here from Colorado State) demonstrating how to celebrate New Years, McMurdo style:

A New Year's tradition at McMurdo is a concert called Icestock. Different groups of people working here (that also happen to be musicians) form bands (to varying levels of success) . Most have only been playing together for a few weeks or months. A big stage is set up outside where each of the bands plays short sets for the crowd of dancing Antarcticans on New Years Eve. So that you can fully experience Icestock, here's a short clip of my favorite Icestock band called Sunday Britches:

To help us ring in the New Year, some people made really cool, big puppets out of random things you can find around McMurdo. They were built on backpack frames and paraded through the crowd of people listening to the live music. They were really creative!

That's how we celebrated the coming of 2009 down here in McMurdo. Today, we are back in the lab processing our soil samples from the field and getting ready to head back out tomorrow morning!

Food, Food, We Love Food!

A very important part of doing research out in the field is staying well fed. All of the food we bring out with us to the Dry Valleys comes in a box, bag, or can. Because we don't always have a refrigerator, we don't really eat fresh foods. We make milk and juice from powder and even use dehydrated eggs. Here's the kitchen cupboards at one of the field camps in the Dry Valleys.
Every science group that comes out to the field camps brings their own food, but it often doesn't all get used. Lots of food gets left in the camp kitchen for other people to use. Some of it never really gets used and sits on the shelves for years and years. I really enjoy browsing the shelves in the kitchen looking for the oldest expiration date on food packages. Granola bars and beef jerky are generally the oldest. Today I found a Cliff bar at F6 camp that expired in 2003. I performed my own scientific experiment to see if Cliff bars change in quality over time. I banged it on the counter and the bar is a little hard. I couldn't bite through it and it tasted like cardboard. I've heard that the oldest beef jerky found and consumed expired in 1996 and that was found only last year.

Elizabeth, Becky, and I take turns making dinner in field camp. Here's a picture of Becky trying to decide between a box of Thai or a box of Mexican.

There is no running water in the field camps, so we try to use very few dishes when we eat. We often don't wash our bowls between breakfast and dinner, and only wipe them out to save water. So sometimes your dinner tastes a little bit like your breakfast. Yum, yum!
We spend large parts of the day out in the field, so we usually eat lunch away from camps. Remember those Cliff bars and beef jerky I was talking about? Those are our lunch! Here's a picture of Becky snacking on some of the food we bring out with us for long hikes.


Even though we don't have the best ingredients to create fancy meals, we eat pretty well out here and thinking of tasty dishes with what you can find on the camp shelves is always lots of fun. Happy Eating!

Process, Process, Process!

We flew back to McMurdo Station from Lake Fryxell two days ago. That ended our first week of field work.

During the past two days in town, we've been busy working in the lab. We have to process the samples that we brought back from the field. We have spent most of our time sieving soils to remove the rocks, then weighing out portions of the soil to measure the amount of salts and nutrients in them. We weigh the soils in this special bench that blows air, which prevents anything floating in the air (like dust) from falling into the bags of soil. We wear gloves so that the oils on our skin don't change the chemistry of the soil. We have only 2 days in town at McMurdo to get as much done as possible before we leave again for the field, so it has been very busy!

We are also getting ourselves ready to go back into the field on Monday. We will be going back to Lake Fryxell, but this time we will be staying on the other side of the lake at the camp called "F6". So my next post will probably be from the field!

Christmas in Antarctica

To celebrate Christmas, we went to another camp nearby on Lake Hoare to be with several other science groups working in Taylor Valley. Christmas with a group is of course more fun than by ourselves, so we hiked over to Lake Hoare on Christmas Eve to spend the holiday with our science family.

To get to Lake Hoare, we had to walk from Lake Fryxell, head up the valleyside a ways, cross over the top of a glacier, then down the other side of the mountain to Lake Hoare camp. It took about 3 hours. Here we are, about half-way through the hike, at the edge of the Canada Glacier where it meets the Lake Fryxell Basin:


There were about ten other people at Lake Hoare camp when we got there. There were limnologists (who study the lakes), glaciologists (who study glaciers), the stream-team (who study the streams), and the two camp managers. They were busy decorating the hut and baking Christmas cookies when we arrived from our hike in the afternoon. It was very warm, friendly, and smelled delicious!

At Lake Hoare, the Christmas traditions always happen on Christmas Eve. We decorate the hut, make and decorate Christmas cookies, and build a very elaborate gingerbread house. The gingerbread house is serious business. It involves heavy construction work, but the finished product is great!

After the decorating is done, we sit down to a great meal prepared by the two camp managers. We had ham, sweet potatoes, corn casserole, homemade dinner rolls, mashed potatoes, and green beans. It was the best meal I've had since I've been here! There was even bread pudding for dessert. Christmas dinner is a fancy-dress occasion. Everyone picks a wig and fancy outfit from the costume box to wear for the evening. To top off the mood, we close all of the shutters so that it's dark inside, and eat by candle and Christmas tree light! Here we are. I'm the one on the right with the silver tinsel hair, Elizabeth is behind me wearing a green feather boa, and Katie is at the end on the left with the tiara.


After dinner, we played the White Elephant present game. We gather around the tree and try to steal the best presents from each other. The present game was followed by an all-night dance party. That way we could work off all the calories we gained from the Christmas cookies and dinner. That is how we rang in Christmas morning- dancing in the hut!

On Christmas morning, we all slept in, then gradually woke up, ate leftovers for breakfast, then said our goodbyes to our "family" at Hoare. We walked our way back to Lake Fryxell, happy and full. It was a beautiful, sunny day that was great for our traditional Christmas Walk!
Of course, on our way back to the camp, we stopped to sample the soil and moss at a few spots along the way. Tomorrow we will do one last day of field work at a stream across the lake, then we're heading back to McMurdo. It'll be nice to get a shower, do some laundry, and sleep inside for a while!

Life at a Field Camp

We have been at the Lake Fryxell Camp for a few days now. There are a few permanent buildings here. The circular building is called a Jamesway. That is where we spend most of our time in camp. It has a kitchen for cooking, tables for eating and working, and wireless internet access! The other smaller buildings are laboratories for doing our science. Outside there is a lot of equipment needed for the science we do here.
We don't sleep in any of these buildings. We sleep outside in tents, like the one in the front of the picture. Because the ground is so rocky, it's hard to pound in tent stakes that won't easily fall out, so we tie our tent down to large rocks. We have very warm sleeping bags and lots of padding. When it's sunny out, the tent feels a lot like a green house, and some nights I get so hot that I actually end up kicking off most of my layers as I sleep!

Because the dry valleys are a polar desert, we have to be very careful about our water use. The water we use is taken from the lake. Water for drinking is filtered or cooked on the stove. We have to be careful that we don't spill any water outside, because in a desert, any small addition of water we make to the soil will make a huge difference to the ecosystem! So, we save all of the water we produce from cooking, washing, and our science. It gets put into barrels like the orange one outside the Jamesway and shipped off the continent at the end of the summer for proper treatment.

Since we have to be so careful about our water, we have no running water or plumbing. Our bathroom is an outhouse where we collect everything we produce. In the picture, the blue door behind my tent is for the outhouse. (I think that's where Elizabeth is walking...) No running water also means we can't shower! We use very little water to wash our faces and brush our teeth.

But, we do have some modern amenities here at the field camp. There's a gas-powered refrigerator, stove, and oven, just like in a normal house. We have a telephone, though the connection isn't always very good. We also have electricity from a big solar panel that you can see all the way to the left in this picture of the lake-side of Fryxell camp:The electricity is mostly used for science. We need to recharge batteries, run our equipment and computers, and of course the wireless internet! But, sometimes we use the electricity for fun. Sometimes we relax after dinner by watching a movie together on a laptop in the Jamesway. (You can see the laptop on the chair in the bottom, left corner). The "couch" we're sitting on is made of plywood with foam sleeping pads strapped to it and covered with an old blanket. Very classy! It's our most comfortable piece of furniture.


(P.S. If our supervisor, Ross, is reading this, I just want you to know that we neeeeever have time to watch movies. We're working all the time, of course! This picture was posed for educational purposes. No relaxing going on here...)

Measuring soil micro-organisms

Soil in the dry valleys of Antarctica is a hard place to live. It is very cold and very dry. There's not a lot of water available, and most of it is frozen. There's also not a lot of food to eat. But, believe it or not, there are organisms that can live in such a harsh environment. The organisms living in the soil here are all microscopic. That means they are too small to see with your naked eye. But, they are definitely there! We are interested in studying how these organisms change the nutrients in the soil. It's important to know how they change the nutrients because these nutrients are needed by all living things.

Because the soil organisms are so small, it's very hard to study what they do. You can't watch them individually unless you remove them from the soil and look at them under a VERY powerful microscope. So we have to use other ways to measure what the micro-organisms are doing.

One of the ways we measure what organisms do is by measuring their respiration. When living things (including people) breathe, we exhale carbon dioxide. If we're sitting still, we breathe very slowly and exhale small amounts of carbon dioxide. If we are very active and run around a lot, we breathe faster and exhale more carbon dioxide. A whole classroom of people running around can exhale more total carbon dioxide than just one person. So, more carbon dioxide is exhaled by larger numbers of more active organisms.

The soil micro-organisms in Antarctica work the same way. If we measure how much carbon dioxide is being produced in the soil, we can guess how many micro-organisms there are and how active they are. More carbon dioxide being produced would mean there are more active micro-organisms.

We have a fancy machine that helps us measure carbon dioxide in the soil. We nest it over the soil, and it measures how fast the amount of carbon dioxide changes over that patch of soil. It's called an IRGA. Here's me using it:
I am interested in knowing how the amount of carbon dioxide changes if you change the amount of water in the soil. So, I've been measuring carbon dioxide near the lake, where the soil is very wet. As I move the machine farther from the lake edge, the soil gets drier. So by moving the IRGA farther and farther from the lake each day, I am finding out how carbon dioxide respired by micro-organisms changes from wet to dry soil. In this picture, I'm making a measurement pretty close to the lake edge. Today, we moved it several meters farther back, where the soil is less wet. Tomorrow, we will move it even farther away where the soil is very dry. From the information we collect, we will know much is being breathed out by the soil micro-organisms as you go from wet to dry soils. That will let us estimate how many organisms they are and how active they are.

That is one of the ways we measure soil micro-organisms. There are many other things we do to measure what's living in the soil, but that will have to wait for another post!