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It’s been a long time since we’ve updated, but we’ve been very busy. After having isolated sampling dates where we were able to get into the Dry Valleys for the first few weeks, we finally ran into two solid weeks of great weather. Today we’ll talk about the experiments we maintained and sampled, what we do with the samples once we get them back into the lab, what sorts of animals we’re looking for in the soil and the trip Diana, Uffe, Byron and Ian took to the Beardmore Glacier.
Our experiments for the Long Term Ecological Research (LTER) work we do here are spread out along the south sides of three lakes in the Taylor Valley. From east (on the right, closest to the Ross Sea) to west (on the left, closest to the polar plateau) the lakes are Lake Fryxell (with F6 camp), Lake Hoare and Lake Bonney.
Over the last week and a half we’ve been to each of our sites at these three lakes and sampled from and then treated another of our long-term experiments, the Biotic Effects Experiment. This experiment has four treatments: added water, increased temperature (about 2 degrees Celsius), increased temperature and added water and a control (which if you remember from our discussion of the stoichiometry experiment is there to provide us with baseline data without the influence of the treatment manipulations).
Adding water is pretty straightforward. Much like the stoichiometry experiment, we added 5.6 liters of water to each plot that was supposed to be watered. We did this with the jugs and watering spouts we used in the stoichiometry experiment. Temperature is also pretty straightforward, and to raise the temperature of the plots we let the sun do the work. The cones we use to outline where we need to water in the Biotic Effects and Stoichiometry experiments are actually used for the temperature treatment. They’re made of nearly-clear fiberglass that helps to trap heat from the sun in the area beneath the cone, and in this way we can leave the cones tightly strapped down to stakes on the plots year-round and let the sun do all of the work for us. You can see the cones placed on the sites below.
With this experiment, we can see what the effects of changes in climate might be on the soil animals in the dry valleys. If the dry valleys get warmer and wetter, our experiment will help to predict in what ways the soil animals will respond. The design also allows us to see how each of these climate variables may affect the soil animals alone, without the influence of the other variable. This means we can also say what proportion of the change we see due to increased temperature and precipitation may be due to the effects of the increased temperature by itself, or the extra water.
While we were out at Lake Bonney, we also set up another experiment that we plan on monitoring for many years to come. Last year this area where our experiments are located got very wet when an increase in streamflow resulted in a large patch of moving water and seeps. We had the boundary of the wet area marked out last year, and this year we were able to put in spikes with copper tags to indicate areas we wanted to sample from over the next several years. Additionally, we also ran three lines (transects) that extended from the areas that had been dry throughout last year through the area that had become flooded and then back out again into dry soil. Each of these transects was located roughly parallel to the others, with one toward the base of the slope our experiments are located on, another halfway up the slope, and a third quite far up the slope. Once we had these sampling locations marked out, we took our first batch of samples, as you can see here with Uffe happily getting some soil for us:
When we sample soil, we do two things. First, we scrape off the very top layer of soil in order to see how much photosynthetic activity the algae that live in this area are undergoing, and then we try to collect the top 10 centimeters in the small area directly under where we sampled the algae. This soil is put into bags labeled with the experiment we’re conducting as well as the particular site or plot the sample came from so that we know the origin of each sample. We then take the bags back to the laboratory and there we extract the animals and measure the moisture of the soil.
Measuring soil moisture is very simple. First we weigh small cans and write down their weights. We then add 50 grams of soil into each can and note the number of the can and which soil sample was added into it. Finally we place the soil cans into an oven at 105 degrees Celsius for a day, which causes all of the water in the soil to boil off and leaves only the dried soil. Once these dried soils are weighed, we can subtract the weight of the can itself and then calculate the difference between the wet and dry soils and then determine what percentage of the wet soil was water.
The process to extract soil animals is much more involved, and we usually have three people performing various steps at the same time. The first step is done while we’re weighing out soil for soil moisture: once the soil for soil moisture has been measured out into a soil can, the person working at the balance also measures out 100 grams of soil for extracting the animals. We do this in a special “laminar flow hood” that helps to filter the air blown over the samples in order to minimize contamination–nematodes are everywhere, and we want to try and extract only the nematodes that are in the soils we have collected. This 100 grams of soil is then placed into a small beaker that is half-filled with water. The soil is then mixed up in the water to make a sort of soup. All of the heavy particles such as rocks and bits of sand fall back down to the bottom of the beaker while the lighter particles float around in the water. These lighter particles include small soil particles, but more importantly they also include the nematodes and other soil animals that we’re interested in collecting.
This soil and water mixture is then poured over a series of sieves and sifted out so that only the very small particles are captured and transfered into a centrifuge tube. We then spin the tubes in a centrifuge very quickly for 5 minutes in order to push all of the animals down to the bottom of the tube. After the 5 minutes is up, we pour out the extra water on top (being careful to keep some of the water that might have animals in it) and then add in the magic ingredient: sugar water. Once we add the sugar water, we mix it up with the soil in the centrifuge tube, which tosses the soil animals back up to the top of the water column. This time we centrifuge the tube for only one minute, and then take it out. All of the soil gets tossed to the bottom of the tube but all the animals stay in the water because the sugar keeps them afloat. We then pour the water out over a very fine mesh screen and then rinse the screen into a clean tube, and voila! We have a small sample of water that contains the animals from all the soil we started with.
When we look at the animals under the microscope, we identify the nematodes to species and then further break them down into the number of males, females and juveniles and how many are alive and dead. We also count other organisms such as mites, tardigrades or rotifers, and you can see some images and movies of these animals here. First you’ll see a tardigrade (or “water bear”) followed by a nematode. Later on, 1:05 in, a rotifer appears. This video gives a good idea of what it’s like to look through soil samples!
Earlier this week Diana, Uffe, Byron and Ian (from the University of Waikato in New Zealand) got a chance to start sampling for another of the grants we have going. Early Tuesday morning they got onto a small “twin otter” plane and flew from the ice shelf outside of McMurdo down to the Beardmore Glacier. This glacier is very far south, and rises from the ice shelf up to the polar plateau–this is the same glacier that Shackleton and Scott used to get up to the plateau and eventually (for Scott) to the south pole. Here they landed near Mount Kyffin, which is mostly covered by snow except for a few areas that have exposed soil. They climbed across the ice and snow over to these exposed areas and collected samples to examine back in the lab.
With these samples, they are looking to see what animals are found on the exposed rock surfaces that act like islands amidst the glacier and snowcover. They’ll take the animals they find and sequence their DNA, and then check to see if the populations of animals they collect have diverged through time and if so try to estimate how much time has passed since the populations were together. They can then compare these estimates with the age of the surface of the soil they collected the animals from and determine whether the animals are newer arrivals or whether they’ve been there since the time the soil patches were isolated from each other. Neat stuff!
It’s been exciting the past couple days! After being stuck in McMurdo Station due to bad weather on Monday and Tuesday–the helicopters won’t fly when there’s too much wind or storms rolling around–we finally were able to get a period of weather good enough for us to leave. Bishwo (a Nepalese graduate student from Brigham Young University) and Zach got ready to catch their helicopter ride to F6 camp in the Dry Valleys when things began to look bad–another weather delay. The weather also continued to keep Diana, Uffe and Byron (a professor from Brigham Young University that’s been on our team for many years) from flying down to the Beardmore Glacier to collect soil samples for one of our other projects.
Fortunately the weather quickly lifted and Bishwo and Zach were called back down to the heliport where they weighed their gear in to let the pilots know how much cargo was on board. Once they had all their equipment they got into the helicopter and then took off–after all the delay, fieldwork at last! The glacier team wasn’t so fortunate, though, and remained stuck in McMurdo for at least another day.
The helicopter flew out over the sea ice and after a half-hour flight over the frozen Ross Sea the pair finally made it to F6 camp on the shore of Lake Fryxell. There’s a permanent hut set up there with a kitchen, entryway and lab area: there’s an outhouse on the side of the building and everyone sleeps in tents. In order to minimize impacts on the Dry Valleys, nothing aside from the huts and other necessary items is left here and all trash and waste must be sealed into containers to return to McMurdo. The research based out of here involves both our work with soils (such as the stoichiometry experiment we described last entry, which is also what Bishwo and Zach flew out to add nutrients to) and work on the many streams that feed into Lake Fryxell from the surrounding glaciers. This work is all conducted for the long-term ecological research site stationed in the Dry Valleys, and involves researchers not only from Colorado State University but also Brigham Young University, Dartmouth College, the University of Colorado and many other universities around the country. Research sites are spread all around both the camp and the lake, making it very much a science-based area.
Once they had landed and gotten their gear offloaded Bishwo and Zach realized that there was another problem. In all the confusion trying to get the helicopter flights out, somehow the last half of the water and nutrient solutions hadn’t been loaded–they wouldn’t be able to work on the experiment without it! A quick call back to McMurdo notified the helicopter crews of the issue and the solutions were to be sent out as quickly as possible. To make use of the time available, Bishwo and Zach walked over with Becky (a member of the soils team from Dartmouth College that had made it out to F6 camp earlier in the week – her blog is here) to check some of the other experiments. The group wanted to be sure that nothing had blown away or broken in the year since the wormherders had last been in Antarctica. Once the team had checked and made sure that everything was still in place and in working order, they went into the hut to get a cup of tea to warm up. While enjoying the tea, a helicopter could be heard getting closer and sure enough, the supplies had arrived and work could begin!
The crew carried the 35 (heavy) 10 L jugs of nutrient solutions over to the stoichiometry plots and got ready to pour the solutions on the appropriate plots. Becky has worked on these plots for several years and so she helped oversee Bishwo and Zach while they carried the solutions over to the plots. They started by adding only water to the plots indicated by Becky that weren’t getting any additional nutrients (the control for the experiment to make sure that any changes in the soil animals were due to the nutrients and not the water that was added).
Once at the indicated plot, they double-checked to make sure they were in the right plot by reading the copper tag anchored on the ground and checking the two plots next to them matched what was shown on the map. Bishwo and Zach then placed clear plastic cones down to outline where they were supposed to pour the liquid and then carefully watered the plots. Each of the different solutions had to be poured on 8 separate plots, and so once they had the water poured they moved on to the carbon and nitrogen solutions, then the phosphorus and carbon/nitrogen and finally the carbon/phosphorus solutions. Here you can see Bishwo carefully applying carbon solution to one of the plots:
The solutions had to be slowly poured onto the plots, so that the water would seep into the soil and not just run off the surface and away from the plots. All of the liquid needs to soak into the soil and completely wet the top 5 inches in order to provide the nutrients to all the animals that lives in that space–if the water were poured too quickly, it would run off the plots and be wasted or could contaminate nearby plots and ruin the experiment. Notice the careful positioning of Zach and Bishwo’s feet as they bent over the cones to pour the solutions without stepping in the plots!
While they had been engrossed in getting the plots treated with the solutions, storm clouds rolled in and it began to snow–no helicopter was going to be able to fly in the storm. The afternoon in the camp was fun and our team got to meet the “stream team” and four “GK-12″ graduate students (their blog is here) from the University of Colorado who were also working out of F6 camp, bringing the total number of people to 9. Everyone played cards and chatted when word came over the radio just as dinner was being prepared around 7:30: There was a helicopter at another camp just to the west that was going to stop at F6 to pick up Bishwo and Zach and bring them back to McMurdo! They quickly rushed to get their gear outside and when the helicopter arrived packed on all of the now-empty jugs and their backpacks and then they were off!
The helicopter quickly flew over the valleys to the edge, where they meet the sea ice. The weather between the Dry Valleys and McMurdo Station wasn’t good enough to fly through, and so the helicopter pilot decided to “boomerang” back to camp. Just in time for dinner!
It snowed off and on all day, with up to an inch of snow on the ground at times. The Dry Valleys are an extremely cold desert (even though they’re cold, they’re also very, very dry as the name suggests) and the snow would disappear quickly–the air is so dry that a lot of the moisture evaporates off before the water in the snow can even get into the soil. Look how different the valleys look covered in snow:
In the afternoon the snow began to clear up, and at 5 pm the helicopter they had tried to go home on the night before took off to refuel and then returned to bring Bishwo and Zach back to McMurdo. They got picked up around 5:45 and after a smooth ride made it back into McMurdo around 6:15. Just in time for dinner!
Now that everyone’s back in town, we’re looking at all of the samples under the microscope to see what nematodes and other soil animals are living in the soil samples we collected. This weekend Zach and Bishwo are going back to F6 camp to work on some of the other experiments there, and Diana, Byron and Uffe are hoping to finally go far south to the Beardmore Glacier with Ian, one of our team members from Waikato University in New Zealand.
Once we had gotten through all of the training we needed to do, it was time to start setting up the lab. This involved unpacking all of the boxes of material we had put away for storage at the end of last year as well as picking up shiny new equipment for the lab for this year. All the things we had carefully washed last year were rinsed and dried before being put back on the shelves where they belong and we picked up things like our microscopes, soil cans (used to see how much water is in the soils we collect), lab computers and chemicals we’ll be using throughout the time we’re here. Now that the lab is all set up, you can see Bishwo hard at work!
Life here wasn’t all work while we get settled in, though! Even though we had to work during the weekend to get everything set up, there was still time to enjoy life in McMurdo. This past weekend featured two of McMurdo’s winter traditions: IceStock, an all-day concert featuring local bands and the Scott’s Hut 10k race.
First up was IceStock on Saturday. The bands started playing at noon on a big stage set up in the middle of town and kept playing until 7. You can see the stage here, all painted up for the festival this year–every year has different stage artwork made up special each year. We missed the first few bands performing, but did manage to hear bands like “Level Five”, “Unsorted Trash” (we have to sort our trash here into things like food waste, recyclables and things they can compress to ship back home to be taken care of) and “Safety Band”. As you may have guessed, Safety Band sang songs about how to avoid getting hurt or doing things that would injure other people–not something you’d hear anywhere else! Here you can see a picture of Bishwo, Diana, Zach, Ross and Uffe at IceStock:
And here’s a picture of the stage artwork:
and one with the last band of the day playing:
There was a short break for dinner at 7, and then the concerts continued until late into the night in different buildings. Some bands played more relaxed, acoustic music and others were more of the loud rock and roll style–something for nearly everyone! Being the diligent scientists that we are, however, we went and made sure that everything was squared away in the lab after dinner and then took the rest of the night off.
Sunday morning, bright and early, was the Scott’s Hut race. The race started at 9 in the morning and was a bit less than 10 kilometers (that’s about 6 miles) from McMurdo Station over to Scott Base (run by the New Zealanders). After running through town, the participants had to race uphill with the wind blowing down on them–not easy–and then down the other side into Scott Base. Once they got there, it was time to turn around and run back. Not many people ran it this year because of the strong winds, but here’s a picture of Bishwo and Byron coming to the finish line!
The real reason we’re here, though, is for the ecology work that we do. Most of the time we’re here is spent getting the lab set up, running our experiments (or keeping them in running condition between years) or looking at all of the soil we collected to see what organisms are present and what effects the experiments might have. Weather has unfortunately kept us from getting into the field just yet–compare the image out our lab window here with the one from last week!
Once we can get into the field, however, we’re going to begin sampling and maintaining the experiments we run here. Our group might change year to year depending on who comes down to work each winter, but our experiments run for many years at a time in order to provide us with information about how the soil system down here works. This week we’re going to be working on the Stoichiometry experiments we have in place at our F6 site. It sounds really confusing, but it’s actually fairly straightforward.
In the Dry Valleys, one of the questions we’re interested in are how differences in nutrients (carbon, nitrogen and phosphorus) between the different sites we have around the lakes in the dry valleys affect the animals and other critters that live in soil. Secondly, we want to learn which of these three nutrients has the greatest effect on the organisms living in soil, so we’re looking for changes in the activity or number of living things in the soil when we add either carbon, nitrogen or phosphorus.
There’s very little plant life to provide carbon to soils (plants undergo photosynthesis and take carbon dioxide in the air and turn it into sugar or use it to grow bigger): you can see how empty these sites look below!
Because there’s so little plant growth in these sites there is very limited amounts of available nutrients in the soils and adding nutrients will therefore increase the number of organisms in the soil and how active they are – nutrients control how quickly organisms (including humans) grow and reproduce. One of the most important and often limiting nutrients is carbon, but sometimes other nutrients also influence growth rates. The field sites we chose for this study differ in the amounts and availability of nitrogen and phosphorus, with nitrogen being limited at Lake Fryxell and phosphorus being limited at Lake Bonney. In contrast, the sites are fairly similar in carbon levels, although carbon is also in short supply. So we predict that carbon additions will have a positive influence at both field sites but that nitrogen is limiting soil function and faunal populations at Lake Fryxell whereas phosphorus is in short supply at Lake Bonney, and a strong positive effect of carbon additions will only be observed if we also add nitrogen and phosphorus at the two sites, respectively.
To get all these nutrients added to the sites, we have to carry in a lot of water with the nutrients dissolved inside. You can see all the containers we have to bring with us below.
We add either carbon, nitrogen or phosphorus by themselves in order to see what happens when only one of the nutrients is added to a plot of soil, and we also add nitrogen or phosphorus with carbon in order to see what happens if two of them are combined–remember, sometimes the soil organisms can’t make use of the extra nitrogen or phosphorus if they don’t have enough carbon to grow. Sometimes we also add nothing, just so we know what the plots are like alone. And finally, because we’re adding all of those nutrients with water, we also add only water to some of the plots in order to make sure that any changes we see are due to the nutrients and not the water!
Once we got into McMurdo and had a chance to settle in, most of us had to go through training to remind us of the right way to do things. Zach had never been down here before, though, and so he had to attend “Happy Camper” or “Snow School”. This is required for everyone new to McMurdo that plans to go off-station for any reason, and teaches you what to do in case of emergency and you get stuck somewhere–things like how to start a small camp stove to cook food, how to set up tents for shelter or how to cut snow bricks to build walls to protect you from the wind and how to dig a snow trench to sleep in if you don’t have a tent! Since we got in late on the 30th of December, this meant that Snow School was going to run from the morning of December 31st into January 1 of the New Year!
The first thing he had to do for Snow School was to listen to some discussions about safety theory and how to minimize risk while gone, and then it was time to travel away from McMurdo off onto the ice shelf, where the snow is deep. It isn’t too far to the place where they set up the camp, but you can really tell you’re in a different part of the world, because everything looks so different! McMurdo sits on Ross Island, which is surrounded by water to the north and ice to the south, and the island itself has three mountains, one of which is much more obvious than the others–Mount Erebus, an active volcano! You can see in the picture the material floating away from the top, but the volcano is very quiet and stable, and isn’t a danger.
Once here Zach’s instructor talked to him about how unpredictable weather can be in Antarctica, and how suddenly snow storms can blow up and possibly catch you while you’re out. He talked about how to use a “survival bag” filled with sleeping bags, sleeping pads (to keep you off the snow while you sleep!), tents, food and a small gas-powered stove. Once this was done, Zach and his group picked a spot to set up their camp and began to raise the tents. They then began to saw block-shapes into the snow to make snow bricks! These bricks ended up being used to build a wall to protect them and their tents from the wind, which would help to keep warm. Even though the weather was really nice, with a lot of sun and temperatures right around 34 degrees, wind would pick up every few minutes and make it feel a lot colder–the wall really helped to keep them warm just by stopping all the wind from hitting the little camp! Here you can see the tents all set up, with the snow-brick wall built to the side of the big tent in the middle; everyone is standing in the kitchen, which was built next.
Now that they had a camp built, it was time to learn how to make shelters if the tents were lost. To do this, they learned how to dig holes into the snow and then hollow out little trenches to sleep in, protecting them from the wind and providing a little spot to put a sleeping bag into. Not the most luxurious way to spend New Years Eve, but after a long day of setting up a campsite, it still felt good to sleep in! A hot dinner was made from dehydrated camping food and then they made cocoa, tea or coffee to stay warm for the next few hours. They stayed up to ring in the new year, and then got their sleeping bags out and settled in for a night under the sky.
Everyone slept in the trenches all night, and got a surprisingly good amount of sleep out of it–six or seven hours at least! In the morning, they all made breakfast on the stoves and then took down the tents and packed them back up into sleds to drag over to a nice warm hut for the next part of their training. After some tea or cocoa to warm up after the night spent outside, everyone had to learn how difficult it can be to get around outside in a white-out blizzard. The super high tech solution to let them experience how hard it is to see and hear in really strong storms? Buckets!
With the buckets on our head, their task was to find a “missing camper” who had gotten lost during a white-out. They were allowed to use anything in the hut to assist them in finding the lost person, and finally settled on good, old fashioned rope. Wandering out holding the rope, they managed to stumble out to (and into!) the outhouse, only to find their friend wasn’t there. Finally, after much tripping and walking into bamboo flag poles later, they found the missing camper and safely returned back to the warm hut where they were allowed to remove their stylish headgear. This taught them the number one rule about going out in bad weather: don’t go out in bad weather! The bucket made it impossible to see, but it also made it nearly impossible to hear anything. This meant that once they got more than a few feet away from something, it was very difficult to tell how far away they were and that made it easy to get disoriented and wander.
After that, it was a simple matter of eating lunch and then waiting for the vans to bring them back to McMurdo. Now Zach is ready to go out with the rest of the group to sample and collect the data that we’ll use to conduct our scientific experiments! Until we can get out, though, we can enjoy the wonderful view out our lab window!