Merry Christmas!

I hope everyone had a great Christmas. For the holiday, I hiked from F6 with the Stream Team to Lake Hoare, where everyone in Taylor Valley gathered for Christmas.

To make the journey, we had to ride the ATV across the ice covering Lake Fryxell to the other side of the lake. Then, we hiked up the hillside, crossed the Canada Glacier and hiked down the other side to the camp at Lake Hoare. It's the Antarctica version of going over the river and through the woods to Grandmother's house.

Here I am with the crew from F6 as we hiked over Canada Glacier:

At Lake Hoare, there are a lot of great Christmas traditions. One of the most fun is building the gingerbread house and decorating Christmas cookies! Here's this year's creation. We use only edible items to build the house, including the Twizzlers that my sister sent me in a care package. This year's gingerbread house is even energy-efficient, with solar power and a wind generator!
After the decorating, we have a big family-style dinner of ham, asparagus, potatoes, and bread pudding. We follow that up with coffee while playing the gift-swap game. Then, we turn the lights out and have a dance party until we get too tired and crawl into our tents to sleep.

It was great to spend time with my Antarctic family in the dry valleys! It was a fun Christmas as always. Here's the beautiful view we had from the front door of the hut around midnight on Christmas:

Have a happy, safe holiday season!

Patterns in Antarctic Soil

One of the most noticeable features of the soil in the dry valleys are the strange shapes that cover the ground. These are most noticeable when you're flying over the dry valleys in a helicopter. The irregular shapes are created by cracks that develop in the soil.

These polygons in the soil are very large. They can be many meters across. To give you a sense of scale, here's an aerial shot from a helicopter of F6 camp where I'm staying right now. You can see the polygons in comparison to the hut.


And here's what they look like from the ground. There's still soil the cracks. The cracks are not gaping holes that you can fall into. They are just crevices filled with finer-grained sand than the rest of the soil.
The cracks are created by the freezing and thawing of the ground ice below the soil. Water in the soil expands when it freezes and shrinks when it thaws, which creates the crack, and the finer-grained soil falls into the crack. Because ice and freezing plays a role in the formation of the cracks, they are called "cryogenic cracks".

Our research in the dry valleys has shown that biodiversity is lowest in the cryogenic cracks. So, when we walk across the soil, we specifically walk in the cryogenic cracks so that we are only harming the least diverse part of the community. As you can tell from the first photo, that means we don't walk in many straight lines!

Cryogenic cracks are not unique to the dry valleys of Antarctica. They are commonly found in cold places where permafrost underlies the soil, such as the Arctic tundra. They're even found on Mars, which is one piece of evidence that leads scientists to believe that there may be water on Mars.

New Outhouse

A helicopter delivered a package to F6 camp. It was our new outhouse!

At the camps in the dry valleys, there is no plumbing. All of our waste material has to be contained in barrels and buckets and shipped off the continent at the end of the season. We can't release it anywhere in the dry valleys, because it is a protected environment. Therefore, we use an outhouse where all of our waste is collected.

At F6, we had an old outhouse that was pretty small and rustic. There was a bucket with a seat that we used for solids. That was covered by an old garbage can lid. For liquids, boys stood outside and used a funnel in a barrel, and girls squatted over a tin can in the outhouse that was then poured into the barrel outside. Here's a shot of the old outhouse:
But the NEW outhouse is much more luxurious! It's bigger. There's two comfortable foam seats with real seat covers: one over the bucket for solids and one where girls can sit over a big funnel that leads to the can. There's a urinal inside for boys, so they don't have to stand outside. But that's not all! There's also hooks to hang up your coat, ventilation panels, and a sunroof! The plexiglass panels let in light, but also heat the outhouse like a greenhouse. Plus it's bigger, so there's more room to store the extra supplies and still be able to move around comfortably. We are very excited to have such a fancy new outhouse!

Here's a video tour of our fancy new outhouse.


Exciting times at F6!

Nunataks

Today I flew back to the camp at F6 on Lake Fryxell in Taylor Valley.

Because there were two stops we needed to make before dropping me at F6, I got to fly over some pretty cool scenery. Instead of coming in the mouth of Taylor Valley from the (frozen-over) sea ice, I flew from over the Asgard Range of mountains that border Taylor Valley on the north side. There are alpine glaciers that cover a lot of the area up there.

This is the view I had coming over the Asgard Range, most of which is covered by the glacier. Just beyond the mountain peaks in the foreground is Taylor Valley. (In the background of the photo are the Kukri Hills, which make up the southern border of Taylor Valley.)

There is a lot of land under the glacier, we just can't see it. However, some of the mountain peaks are tall enough to poke out of the glacier. These are called "nunataks". You can see an example of a nunatak on the right-hand side of the picture above. Nunataks are isolated from the rest of the land by the surrounding ice, which is how they get their name. "Nunatak" is an Inuit word that means "lonely peak". They are not created by the glacier, but were a part of the mountain range before the glacier was there. While organisms living on land below the glacier will probably be killed by the glacier, they may be able to survive for a long time on the nunatak. Scientists find all sorts of organisms living on nunataks in Antarctica, such as bacteria, lichens, and mites. So, even though nunataks are isolated, they are not uninhabited.

Back in Town

Friday evening I returned to McMurdo Station from Cape Royds. In Antarctic lingo, we call that going back to "Mactown." There, I met up with two more of my group members that have just arrived in Antarctica. Here we are, all three together!We will be a three-member team until early January, when Ross (our fourth member) arrives.

During my two days in town, I've been processing the samples I collected from F6 and Cape Royds. One of the things I have to do is clean the soil off of the moss I've been collecting, so that I can measure the nutrient content of the moss back in the U.S. To do this, I have to place the moss in a dish under the microscope:
I showed you before what patches of moss look like in the field. It looks like a piece of carpet, and it's hard to tell the individual plant stems apart. This is what a piece of that patch looks like through the microscope lens:The green parts you see are just a small part of the moss. Those are the leaves, which grow on a stem. Below all of those green tops are a large mass of brown rhizoids, that work like roots for keeping the moss in place and collecting nutrients. In this picture, the stems are bigger than the rhizoids, but in the moss I work with, there's a lot more rhizoids than stems. There's a lot of soil stuck in that tangle of rhizoids, and I have to wash all of that out. If I don't, when I take my nutrient measurements, I won't be able to tell the difference between what nutrients are in the moss versus the soil. It's very time-consuming, and requires a lot of patience!

Once the moss is clean, I put it in an oven (at a low temperature) to dry it out so that I can safely ship it back to the U.S. for analysis.

This is just one of the chores I've been doing since I've been in Mactown. It's been busy, because tomorrow I head back to F6 on Lake Fryxell for more field work!

[Photo credits: Moss diagram from http://www.botany.hawaii.edu]

The Wonders of Penguin Poo

Yesterday evening I left Lake Fryxell and flew to Cape Royds, one of the penguin rookeries on Ross Island.

While I am here, I will be measuring respiration from soil covered with penguin poo! When most soil organisms respire, they produce carbon dioxide (abbreviated CO₂). Humans do this when we breath, too. By measuring the amount of CO₂ coming out of the soil, we are measuring how much the soil organisms are respiring. Since penguin poo has a lot of nitrogen and phosphorus, I expect much more CO₂ to be respired from these soils than the dry valleys. (Just think about what you would do... if someone gave you a lot of yummy things to eat, you'd run around and be more active, and therefore respire more. The same thing happens for soil organisms!)

Here's a measurement being taken at the rookery. All the light-colored pink and tan stuff... that's penguin poo! The small machine down by the lake edge is what measures CO₂ coming out of the soil.

The penguins are very funny to be around. Many of them are very curious... just as curious as we are about them! Here's Adrian, who volunteered to help me with my measurements today. Who's studying who?

The great moss hunt

This is my second day of field work in the dry valleys. Today I was sampling along stream edges for moss. I've been sampling moss for a few years in the dry valleys, and I'm trying to sample from new areas this year that I haven't sampled in the past.

Moss is the only true plant in the dry valleys, though it hardly fits the definition of "plant" that most of us think of. Moss are bryophytes, which are a type of non-vascular plant. In the dry valleys, where temperature, sunlight, and dryness are very harsh to deal with, they grow very slowly. We find them mostly in small patches near sources of water, like streams and snowpatches. Here's a photo of some moss I was sampling at Crescent Stream. Can you see the moss? It's reddish-brown and looks kind of fluffy.During the winter there's no sunlight for photosynthesis, but during the summer the sun can be so intense that it can actually damage plants. (Largely due to the intense UV radiation that I mentioned a couple days ago.) Most of the time you do not find moss that is lush and green, because it's usually too cold, too dry, or there's too much sun damage. The moss I find tends to be brown, because it is "moribund". That means it's not dead, but also not very healthy. The moss is less active in that state, but parts of it can be. I can find green moss in spots where it's protected from the intense sun, though. Here's a little patch of green moss that I uncovered when I moved a rock out of the way at Crescent Stream.

Just like all other plants, moss need water and nutrients to grow. I want to know where the moss is getting its nutrients from. I'm interested in the nutrients in moss because, when mosses die, they decompose in the soil. The carbon and nutrients released from mosses when they decompose are probably a very important part of the soil food web that our group studies. So, when I sample the moss, I also sample the soil, stream water, and ground water, which are the possible sources of nutrients for the moss. You can see some of my tools in the photo above. I scoop the moss into a bag with a spoon, then the soil beneath with a little plastic shovel. I take stream water right out of the stream into a bottle. The trickier part is getting the ground water. To do that, I use a miniature well called a piezometer. Essentially, I insert a tube into the ground until it hits the ground water, then I use a vacuum pump to pull the water up into my flask. Here's a video showing you how it works (as well as some nice scenery along Crescent Stream!).



Since the dry valleys are a desert, moss need to grown near a source of water. The easiest place to find them is right next to a stream. So, to do this sampling, I tagged along with the Stream Team as they went about their daily chores at some of the streams. They have to measure the amount of water flowing in each of the streams and take stream water samples for chemistry. Since I can't travel by myself, I was able to go to the streams they scheduled to visit today to do my moss sampling at the same time. This is what they were doing while I was sampling moss:I was able to sample moss from four streams since I've been here, all along the south side of Lake Fryxell. I hiked from one end of the lake to the other, stopping at each un-sampled stream area that I came across. I'm tired!