This BEE doesn’t sting!

Taylor Valley, Antarctica

Diana, Ross, Martijn, Ashley, Ruth, and Sabrina traveled to Taylor Valley to apply scheduled treatments to the Biotic Effects Experiment (BEE) plots. The  BEE plots are located at 3 places in Taylor Valley: near Lake Fryxell at F6, near Lake Bonney, and near Lake Hoare. All of the BEE plots were established during the 1999-2000 season, and are sampled every few years. We are not sampling these plots this year, as that sampling was just completed last field season (to read about sampling the BEE plots click here).

Helicopter leaving after dropping our team off at F6 camp, Taylor Valley, Antarctica.

Lake Fryxell in the foreground, with the Commonwealth Glacier behind in Taylor Valley, Antarctica.

There are four different treatments at the BEE plots:

1. Control (no treatment)
2. Soil warming with chamber
3. Water added
4. Soil warming and water added

Martijn carries the supplies that we’ll need to the field site near Lake Bonney!

This experiment allows us to explore the Antarctic soil ecosystem’s response to environmental change. We expect that soil temperature and moisture will increase in the future due to climate change. With the BEE, we can study the effect of these changes on the soil animals in the dry valleys and our experiment will help predict how the soil animals will respond to warmer and wetter soil in the future. The design of the BEE also shows how each of these climate variables may affect the soil animals alone, without the influence of the other variable. This means we can determine what proportion of the change may be due to the effects of the increased temperature by itself, or the extra water.

Ashley (left) and Martijn (right) add water to the water addition plots at the BEE site. The chambers in the picture warm the soil by trapping solar heat and blocking wind. 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.

For the treatments, the soil warming is continuous (with the use of the soil warming chamber, see photo above) during the austral summer;  however, we need to apply water to the ‘water added’ plots each year to maintain increased soil moisture for those treatments. Adding water is pretty straightforward. We added 5.6 liters of water to each ‘water added’ plot. We did this using jugs (pre-marked for measuring the appropriate amount of water) and watering spouts to help distribute the water softly and evenly. As Diana described to us, it feels much like “watering your garden.”

Ross explains the Biotic Effects Experiment to Ruth near Lake Fryxell.

 

Coming up next: sampling the new P3 experiment, and working in the lab to extract, identify, and count nematodes!

Can’t wait for more? Here’s a beautiful, female Scottnema lindsayae to hold you over until next time!!

Preparing for a field season in an extreme environment: Snow School

Once in Antarctica, there are some necessary training procedures to ensure everyone’s safety while working in and studying this extreme continent. Ashley, Sabrina, and Ruth had never been to Antarctica before and were required to attend “Happy Camper”, AKA “Snow School”. This training is essential for everyone new to McMurdo who will go off-station for any reason (field work, collecting samples, tending experiments). Anyone who has already been to McMurdo and participated in Snow School previously also gets a shorter, “Refresher” course upon arrival.

Ashley is ready for Happy Camper (Snow School)!

Snow School teaches about cold weather and outdoor skills, hazards, and what to do in case of certain emergencies (such as getting stuck in the field during bad weather). This training lasts for 2 days and covers: how to use high frequency radios, send emergency signals, set up tents, cut snow blocks to build walls for wind protection, dig a snow trench to sleep in if you need shelter, and how to maintain body warmth in frigid temperatures. Our Snow School session had 10 participants, and together, we learned and practiced these techniques, built a camp, cooked meals, and practiced rescue/emergency scenarios. First our group set up tents for the camp. We learned how to set up the Scott tent, which was designed for and used by the R.F. Scott expeditions in Antarctica in the early 1900s. We still use these tents today because the design is perfect for standing up to the tough Antarctic weather (plus, you can cook inside of it!!).

Our group sets up the Scott tent!

Next, the happy campers built the snow wall to protect the camp from wind and blowing snow. Even though the temperature was just a little below freezing, cutting snow blocks is hard work and warms you right up! Ruth and Sabrina took off their parkas while working to avoid getting too warm and sweating too much.

Ruth (Left) and Sabrina (Right) cut snow blocks to help build the camp’s wall. The wall will help protect the campers from wind and blowing snow.

After the wall was in place, the group learned how to make shelters if the tents were lost (such as in a storm). To do this, they learned how to dig into the snow and then hollow out trenches to sleep in. The trench protects from the wind and harsh weather and provides a cozy place to snuggle into a sleeping bag. Ruth and Ashley slept in the trenches that they dug, while Sabrina opted for one of the tents – all three got a good, solid, and warm night’s rest.

Sleeping trench with the finished camp (completed snow wall, tents, and snow kitchen) in the background!

Completed Snow Camp!

We also learned about communications while in the field, we discussed VHF radios, HF radios, Iridium phones, and signal mirrors. We practiced using the VHF radios and HF radio. We set up the HF radio and called South Pole station (they were expecting our call!) to run through the whole radio process.

Our Snow School group learning about the HF radio!

After 2 days of Snow School, we headed back to McMurdo Station. We are all ready for a safe and productive field season in Antarctica!!

View of Mount Erebus from our Snow School camp!

Preparing for a field season in an extreme environment: Extreme cold weather gear

Before flying to Antarctica, the Wormherders had a few days to prepare for our field season in Christchurch, New Zealand. Christchurch is the staging place for the United States Antarctic Program (USAP). From there, USAP participants deploy to McMurdo and South Pole stations.

USAP Building in Christchurch

While laying over in Christchurch, we went to the USAP’s clothing distribution center (CDC) where we were issued our customary ‘orange bags’ containing the necessary extreme cold weather (ECW) clothing and got prepared to go to McMurdo Station in Antarctica. We were each issued: parkas, windbreakers, snow pants, bunny boots, balaclavas, hats, mittens, gloves, socks, goggles, long underwear, and fleece pants, shirts, and jackets! We had to try everything on to check the fit of our gear (better to find out at the CDC if something does not fit or is not comfortable than in the field in Antarctica!). Then, we were ready to go to Antarctica!

Here’s Ruth trying on her big red parka! Looks good!

There’s so much gear to take – it gets all spread out in the changing rooms! We take everything out of our orange bags and try it all on! Here’s Diana trying on her bunny boots (Left), Ruth in the fleece pants and parka (Middle), and Sabrina in the windbreaker (Right).

The ECW gear will keep us warm, protecting our bodies from extreme cold and wind while we do our work in Antarctica. We even have to wear our ECW gear for our flight to Antarctica in case of an emergency and we need to stay warm.

Wormherders in the USAP terminal in Christchurch ready to board the plane! (L-R: Martijn, Diana, Ashley, Sabrina)

We caught our first views of the Antarctic continent from the plane!

With our ECW gear, we will be better able to stay warm and safe while collecting soil samples and performing experiments while in the field in Antarctica! Stay tuned: new blog coming soon about Snow School, which teaches newcomers about safety and survival in the harsh, cold conditions of Antarctica!

Wormherders back on the ice for the 2013 field season!

Happy New Year to you all!

The  McMurdo Long Term Ecological Research (LTER) Soils Team this year consists of Diana Wall, Martijn Vandegehuchte and Ashley Shaw from Colorado State University, John Barrett, Kevin Geyer and Eric Sokol from Virginia Tech and Ross Virginia and Ruth Heindel from Dartmouth College. The season started with a sequence of flights from Denver to Los Angeles to Sydney to Christchurch, where we had to wait a day to get our extra cold weather gear issued and fitted. So we visited the Canterbury Museum and the botanical gardens. The museum had a temporary exhibition about Scott’s last expedition, with great information about Scott’s expedition to the South Pole and some interesting pieces such as handwritten lecture notes by Scott. The next day we boarded a C-130 Hercules airplane for an eight hour flight, which was fitted with skis so that it could land on the ice runway which is in poor shape at the moment because some strong winds deposited sediment onto the runway which causes it to melt. We had just stepped out of the airplane and were greeted by an excited Adélie penguin. Our ride to McMurdo station, Ivan the Terrabus, actually had to drive onto a “magic carpet” that was then pulled by a tractor across the ice. The next day the new team members Ashley, Sabrina and Ruth went to Snow School, which you will read more about in the next post. In the meanwhile the others did a refresher survival course, a course on environmental safety and some other training. We spent the past few days planning the field work, setting up the lab at McMurdo and getting our field gear ready. Right now the snowy weather is keeping us from flying a helicopter to the field sites, but hopefully that will change soon and we can go out to the Dry Valleys!

Team B-507-M has landed on the ice.

Stoichiometry Experiment

Byron, Jeb, Eric and Martijn went out into the field recently to sample and treat the Stoichiometry Experiment. This experiment is replicated at two different sites within Taylor Valley; one near Lake Fryxell and one near Lake Bonney, at the Bonney Riegel. The purpose of the field experiment is to investigate which nutrients are most limiting to Antarctic Dry Valley soil communities and the ability of soil communities to respond to nutrient additions. You can read more about the sampling of this long-term experiment during the 2010-2011 season on Dr. Becky Ball’s blog http://polarsoils.blogspot.com/2010/12/fertilizing-polar-desert.html.

Because Dry Valley soils are generally carbon limited, we wanted to test if i) carbon additions will increase soil respiration (a measure of the level of activity of organisms) and biomass of soil communities, ii) the nutrients nitrogen and phosphorus alone will not increase the activity of organisms and iii) elevated levels of nitrogen will increase nematode mortality. In addition, the soils of the Bonney Riegel have high nitrogen and ow carbon and phosphorus content and are expected to respond to the addition of carbon, or carbon and phosphorus, but not to nitrogen additions. Fryxell soils on the other hand have a high phosphorus content, and nematode communities are expected to respond most to carbon and possibly carbon and nitrogen additions, but not to carbon and phosphorus additions.

The experimental design consists of different plots that are organized into replicate blocks within each site. Each plot is treated in one of the following ways:

1. An unamended control
2. Addition of water only as a control for the water that is required to add the nutrient elements
3. Addition of carbon in the form of mannitol, a compound found in algae
4. Addition of nitrogen
5. Addition of phosphorus
6. Addition of both carbon and nitrogen
7. Addition of both carbon and phosphorus

The helicopter leaves after dropping off the wormherders at F6 Camp near Lake Fryxell

Jeb carries a jug with nutrient solution from the landing pad next to F6 Camp to the experimental site.

The Von Guerard stream drains into Lake Fryxell with the Commonwealth Glacier in the background.

The team went to the Fryxell site on Wednesday, December 21 and then to the Bonney site on Friday, December 23. They first sampled all of the plots. The topmost layer of the soil was first collected for measurement of the chlorophyll a concentration, which helps provide an estimate of the photosynthetic productivity of the soils.  Soil samples from each plot were then collected to a depth of 10 cm, to be used in measuring soil chemistry, soil moisture and extractions of the soil animals present. The samples were brought back to the Crary Lab at McMurdo station where the soil invertebrates were extracted and counted. After sampling the soils, the nutrient treatments mentioned above were applied to the plots.

The weather on both days was very nice, and the landscapes were stunning as always. On Friday at Lake Bonney, the helicopter was a little late to pick the team up at Lake Bonney, so there was some time to explore the area. Martijn walked up to the edge of the Taylor Glacier, named after Griffith Taylor, geologist and leader of Scott’s Western Journey Party of the British Antarctic Expedition (1910-14). The glacier had been discovered by Scott during the British National Antarctic expedition (1901-1904) but Scott thought it was a part of the Ferrar Glacier at the time. Taylor, however, discovered that these were not parts of the same glacier, but two glaciers side-by-side.

Jeb and Martijn are using jugs with a pour cap and open top chambers to apply nutrient solutions to the soil plots.

The edge of Taylor Glacier.

Sampling the BEE plots

While the rest of the LTER Soils team was busy setting up the new experiment near Many Glaciers Pond, Zach, Jeremy, and Martijn went to sample soil and apply scheduled treatments at the Biotic Effects Experiment (BEE) plot near Lake Fryxell at F6 in Taylor Valley, one of three locations where BEE plots have been established in the Taylor Valley. All of the BEE plots were established during the 1999-2000 season.

F6 is the name for a U.S. field camp situated near where Van Guerard Stream empties into Lake Fryxell. Field camps have been established at strategic locations throughout the Dry Valleys to support ongoing scientific work in the area. They serve as camping, staging, and emergency survival locations for scientists.

F6 field camp

Van Guerard Stream

The BEE plots (stakes and ITEX chambers seen) with Lake Fryxell and the Commonwealth Glacier in the background

There are four different treatments at the BEE plots:

1. Control (no treatment)
2. Soil warming with ITEX chamber
3. Water added
4. Soil warming and water added

The purpose of the experiment is to see how the soil ecosystem throughout Taylor Valley will respond to environmental change. As predicted by climate change models, it is expected that the soil temperature will increase and that more water will be present in the soil.

Zach holding a spare ITEX chamber used to add water to the water only plots. Permanent chambers are staked into the ground in the background.

The first step was to sample soil from the 24 plots. A few of the plots still had ice right underneath the surface from adding water last year! We had to get creative to chisel out enough soil to sample. Next, we needed to add 5.6 liters of water to the “water added” plots. Our final task was to perform maintenance on the ITEX chambers by making sure that they were all strapped down securely. Strong katabatic winds in the Dry Valleys can destroy experiments if they are not securely anchored.

Zach and Martijn filling up a portable watering can with water

Jeremy watering a temperature warming and water added plot

We were able to finish up our work quickly so the helicopter picked us up a little bit early.

Beginning of 2011-2012 Season

The Wormherders are back on the Ice!

The crew this season consists of Dr. Martijn Vandegehuchte and Zach Sylvain, both from Colorado State, joined by Dr. Byron Adams, one of the LTER co-PI’s from BYU, and his student Jeremy Whiting. We’ll also be working with other members of the McMurdo LTER Soils Team throughout the season.

Since this is their first season on the Ice, Martijn and Jeremy had to do snow school, perhaps more famously known as “Happy Camper” school. The basic premise is that snow school prepares you to survive in Antarctica for a few days in case you are in a survival situation. You also learn how to set up a proper field camp. The class lasts a full day and half, including an overnight stay on the McMurdo Ice Shelf.

Martijn built a snow trench, which really ended up being more like a cave. He crafted stairs, built a cold sink (a dip in the cave for the cold air to settle), and had a heavily fortified roof. Despite the snowfall during the night, he was nice and warm inside his trench.

Martijn's cozy snow trench

Jeremy reported that he had a great night of sleep. Everyone was disappointed that he slept in a tent rather than in a snow trench. He said that snow school was a lot of work but contained valuable training for camping in general, especially snow camping.

A row of mountain tents at snow school

We have already returned from our first sampling trip in the field. We went to the south side of Lake Hoare in Taylor Valley to sample the soil of two experiments– the Long Term Monitoring (LTM) plots and the algae addition plots. The LTM plots are a collection of 64 1-meter square plots with a variety of treatments applied to them. The treatments include increasing temperature, adding water, adding simple table sugar (sucrose) mixed with water, adding natural sugar (mannitol, a sugar found in algae) mixed with water, and different combinations of each of those. Additionally, there are plots established as controls. The experiment was set up during the 1993-1994 season and the treatments discontinued during the 2004-2005 season. Since then, Wormherders have continued monitoring the recovery of the soil ecosystem to document the changes. Later, actual dried algae (without water) was added to a separate set of plots and another series of controls were established as well. These 16 plots became known as the algae addition experiment, or just the algae plots. The experiment was established in the 1994-1995 season and was decommissioned at the same time as the LTM experiment, so our current sampling is to document the recovery of the soil ecosystem just like with the LTM plots.

Zach and Byron sampling the Algae plots

Martijn and Byron sampling the LTM plots

After the sampling was complete, we dropped off Byron at a new experiment being established near Lake Fryxell while the rest of the Wormherders returned to McMurdo for sample processing. We’ll talk more about the new experiment in a later post.

Biogeography

Individual species have ranges that limit where they live–not all species are found everywhere. For over a century, naturalists and ecologists have worked to discern what governs the limits of those ranges, and therefore determines what species are in a given location or where a species might be found. This field is known as “biogeography” and it demonstrates the intricate linkages between ecology and evolutionary biology. The most obvious foundations for this field of study were set down by Darwin during his voyage on the Beagle (seeing all the different organisms spread across the globe helped to get him thinking about his theory of evolution by natural selection), as well as by Alfred Russel Wallace, a less well-known contemporary of Darwin’s who independently and near-simultaneously came up with the theory of evolution of species while studying birds in New Guinea (Wallace even has an imaginary boundary named after him that separates the very different organisms of Asia from those of the Australian and New Guinean areas).

Questions about what limits species ranges aren’t limited to organisms like birds, trees or mammals, though. Part of the work we do down here is looking at what controls the ranges of the species of soil animals we find, and how long those animals have been where they are. In order to do this, we have to get out of Taylor Valley (where most of our work, such as the LTER, is carried out) and collect samples from the other valleys and areas of exposed soils (such as nunataks, or mountaintops that stick out from glacial cover). When we do this, our aim is to try and cover a variety of different habitat conditions, such as available moisture, visible mosses, algae or lichen, the amount of salts in the soil, size of the soil particles, how much exposure to sun the area gets and other factors that may influence how habitable different places in the valley are, which can inform us as to why we do or don’t find certain species in a given location. Last year, Byron, Uffe, Diana and Ian Hogg (our colleague from Waikato University in New Zealand) were able to get down to the Beardmore glacier and collect samples at many different locations there, which is much further south than the Dry Valleys. This year, we were fortunate enough to have Ian and Jeb Barrett (another of our colleagues, from Virginia Tech) send us samples from this region again; in addition, a group of New Zealand researchers led by Craig Carey have been sending us samples from some of the more southern Dry Valleys such as Miers and Hidden Valley.

This year, Byron, Uffe and Zach were able to get to some less-visited parts of the Dry Valleys to collect samples. They first started by going to Mount Suess, which is further north in the Transantarctic Mountains than Taylor Valley. Mount Suess sticks up out of the surrounding Mackay Glacier, and has a lower ridge that projects from the east side of the mountain. This ridge is covered with soil and dotted with small meltponds, which harbor mats of algae and patches of moss. Here you can see a picture of the mountain, with the soil-covered ridge in the foreground.

And here is a picture of one of the small ponds.

The three of us each went a different way from the helicopter, while the pilot stayed by the helicopter for our return. Each of us had a radio so that we could check in periodically, and to make sure we were all okay–if something happened to one of us, we could let the others know. Uffe went downhill and sampled by some of the meltponds and surrounding area while Zach moved along a small rocky ridge and Byron moved along the top of the ridge toward some other small ponds. Below you can see an example of one of the patches of soil we sampled, and note the small patches of green moss along the bottom of the rocks in the top-center!

We spent an hour and a half on the ground here collecting samples, and then got back into the helicopter to travel to Wall Valley, named after our own Diana Wall! Wall Valley was a short 30 minute flight west and slightly south of Mount Suess, and we passed over some pretty stunning areas that make you realize how big the Dry Valleys are, as you can see here:

Right before we got to Wall Valley, we passed Virginia Valley, named after Ross Virginia, from Dartmouth College, whom Diana has worked down in Antarctica with for over 20 years! As we made our approach, we got a picture of Wall Valley:

Previous sampling at Wall Valley by the Wormherders wasn’t successful in recovering nematodes, as the soil down at the bottom of the valley is too high in salts, which the nematodes can’t tolerate. So this time, we went up along the edge of the valley, sampling in the scree piles that slope up along the valley’s walls. Here you can see the helicopter on the valley floor, and up to the top right stretches a scree slope that Uffe has gone up to sample:

Again, we collected samples for an hour and a half and then made our way back to the helicopter to travel to our last destination, Hawkins’ Cirque. The Cirque, named after the head helicopter pilot at McMurdo, is a small hemisphere-shaped break in the wall of Wright Valley, and sits nearly all the way back in the valley just above the glacier. Here you can see across the Cirque, with the glacier to the left:

After we finished collecting samples, we posed for a group photo: from left to right are Uffe, Byron and Zach.

Once we’ve extracted and had a chance to examine these samples under the microscope, we can look at these data together with the data from other samples collected by ourselves and our colleagues, and begin to put together a better picture of what governs why we find species of soil animals where we do in the Dry Valleys. By looking at overall patterns in distributions, and through use of several dating tools (both by examining age of the exposed rock surfaces as well as comparing the times that different populations of animals in different areas may have been separated by, using molecular genetics), we can start to explain how dispersal throughout the valleys may have occurred, and why some areas were colonized while others were not!

Players or Poseurs?

Dry Valley soils are cold and salty – basically the same environmental conditions that are used for long-term storage of DNA. Sure, Dry Valley soils may be diverse, but are all of these different microbes actively playing a role in soil ecosystems? Or do they just blow in here from other places, hang out in the soil, but never actually contribute anything? Because past studies inferred diversity based on the presence of DNA, it is it possible that the diversity of microbes that play active roles in Dry Valley ecosystem functioning is only a small subset of the microbes present in the soil? Dry Valley soils look diverse, but is the diversity functionally relevant?

Suppose for a moment that we were collecting DNA from Siberian ice cores and inferring ecological function based on the taxonomic affinities of the DNA sequences. When we encounter a chunk of frozen wooly mammoth tissue what would we infer about biological diversity and ecological function? That giant herbivores are running around and shaping Siberian ecosystem processes? Clearly our inferences would be a poor reflection of what actually goes on!

Long-term climate observations by the McMurdo Long-Term Ecological Research group are revealing increased frequency and magnitude of ‘pulse- events’ – periods of rapid warming and ice melt that lead to increased liquid water moving across/through the Dry Valley landscape. Which microbes are active in dry soils? Which microbes are responding to pulse events? Which microbes are completely dormant, waiting for more favorable conditions?

To answer these questions we set up a contained experiment that will capture the microbial response to a pulse wetting event. In the experiment we wet some soils with stable isotope labeled water (O18). The microbes that respond to the wetting event by taking up the O18 will incorporate the label into their DNA. We then extract the DNA from all the microbes in the soil and separate the strands of DNA that have incorporated the label from the strands of DNA that did not incorporate the label. We then sequence the two pools of DNA to reveal which taxa responded to the pulse and which did not – essentially, when it comes to identifying who responds to pulse events, we’ll be able to distinguish the players from the poseurs. Additionally, in order to link the response to actual ecosystem processes, we are measuring CO2 flux in the soils as a surrogate of microbial activity. For example, soils pulsed with water are expected to increase in ecological activity, and thus an increase in CO2 flux through the soil ecosystem.

This involved several steps. First, the experiment was set up conducted near the McMurdo Long-term ecological research (LTER) stoichiometry plots at F6 (Lake Fryxell, Taylor Valley). We outlined a patch of soil 8 m long and 1 m wide, with 8 replicates of 1 m2. Six PVC collars were placed in each of these 8 replicates, color coded to make it easy to tell which sampling period each represented – a control that wasn’t treated at all, so we’d know what the background of each little plot was, and collars to be sampled at 12, 24, 48, 72 and 144 hours after the treatments were added. You can see the collars here:

These collars were placed into the soil, one of each color-coded sample per plot—the locations of these colors within the small plot were randomized beforehand, and here you can see Uffe setting the collars into the soil as Zach reads off where each is supposed to go.

Once the collars were in place, Diana went around with a ruler to measure how much space was between the surface of the soil and the top of the collar—this is important because the machine that Byron would later use to measure how much CO2 was emitted from each plot needs to know how much space is being measured!

Once this information was collected, Uffe and Zach added water to the plots (the treatment), and Byron added the O18 to the experimental plots. Here you can see Uffe and Zach carefully treating their collars, and in the background Byron is taking respiration measurements:

Byron then had to stay out all week (and will have to go out once more) in order to take the respiration measurements at each time period—one 12 hours after the treatments were conducted, one 24 hours later, and so on until all the appropriate readings were taken. The microbial responses are collected in a time series of 12, 24, 48, 72, and 144 hours. The DNA sequencing and analyses will be done off the ice at Brigham Young University. Here you can see him set up to take these measurements.

Kicking off the field season in 2011!

Happy New Year, everyone! The Wormherders are back on the ice!

We began our field season with the necessary (but not exactly pleasant) travel from the United States on the 31st of December. Our field team for the season met once again in Los Angeles, with Diana Wall and Uffe Nielsen flying from Denver, Colorado, Byron Adams from Sacramento, California and Zach Sylvain from Portland, Maine. From LA, it was roughly a 13 hour flight to Auckland, New Zealand and then another hour to Christchurch. Although we left at 11:30pm on December 31st, we didn’t arrive into New Zealand until the 2nd of January because of the International Date Line–a whole day, lost! Fortunately we didn’t have to wait long before heading down to Antarctica, and so late at night on the 3rd, we caught our C17 flight (seen here landing on the ice runway at the end of last field season) down to McMurdo.

Once we had arrived in Antarctica, we spent the morning going through a wide variety of updates about the facilities and responsibilities down here, and then began to set up the lab. The flight had arrived very early in the morning on the 5th (we started our first briefings upon arrival at 5:30am!), and so most of our group opted to take a quick nap before getting to work. What sort of work goes into setting up the lab, you ask? First, many pieces of equipment must be picked up and moved into our empty lab, such as microscopes and a variety of chemicals as well as glassware such as beakers, flasks, and vials. How much glass (and plastic) ware do we need to carry out all the extractions we do while we’re down here? Quite a bit!


On the left is a cart full of plastic falcon tubes that we use to collect the nematodes during extractions (and the caps to the tubes), with a pile of plastic spoons and scoops below–to the right are all of the plastic beakers we need for our extractions, as we mix soil with water in these prior to sieving (more on extractions later!).

After two days of gathering everything we required to start working, we finally were able to begin extracting soil samples in order to see what animals (nematodes, rotifers and tardigrades) we can find. This is the good stuff–taking the soil and running it through all the steps we do in order to see what lives within it is exciting, letting us explore the mystery of where we might find life on this harsh continent. Fortunately, we had many samples from a colleague stored in a freezer waiting for us, so we were able to get to work today without having had to go into the field just yet! Each of us helped in extracting the samples in order to get the animals out and under the microscope. Zach began by weighing out 100g of each soil sample into one of those plastic beakers shown above: we weigh the soil samples so that we can compare each sample to every other sample more easily.

After a sample has been weighed, it gets mixed with water in the plastic beaker, and the water is then poured over two sieves stacked together–this helps strain out some of the soil and rocks and collects liquid with the soil animals on the sieve at the bottom, which has very small holes in it to catch the animals but let most of the water flow through. The sieve is then rinsed over a funnel into one of those small plastic falcon tubes to collect the soil animals (and some residual soil). Here you can see Diana rinsing the sieves between samples, which she is doing in order to prevent one sample from contaminating another: if she didn’t do this, we may end up with animals from one sample being transferred to another, which would provide incorrect data of what lives in each area the samples were collected from.

Samples in the falcon tubes are then passed to someone operating the centrifuge. Here, the samples from the first run of the sieves are checked to make sure the water levels are roughly equal and then are added into the centrifuge four at a time: this first run lasts five minutes, and helps to move all the soil animals down onto a pack of soil. Once this first spin through the centrifuge is complete, all but the very last remnants of water are poured out as waste–the vast majority of soil animals are all tightly packed along with the soil at the bottom, and not in the water in the tube. We then add a solution of water and sugar, mix the soil up into this to re-suspend the nematodes into the solution, and then replace the tubes into the centrifuge for an additional minute. In this last centrifugation, the soil is spun into the bottom of the tubes while the soil animals remain suspended in the sugar solution. Here you can see Byron checking the level of water in the falcon tubes prior to operating the centrifuge:

When the second spin through the centrifuge is complete, the samples are passed back to be sieved once more, this time over a small sieve with an extremely fine mesh. This sieve is then rinsed once more over a new falcon tube, and all of the soil animals are concentrated into this tube for examination under the microscope. In this image, Uffe is looking at a sample under the microscope, where he will count the number of living and dead nematodes from each species present, as well as the number of rotifers, tardigrades and other soil animals.

These numbers will be entered onto a data sheet and then be checked so that we can conduct analyses on our data later. Once we have completed looking at all the samples from a given experiment, the samples will be preserved with formalin and then packaged to be shipped back to the US, along with the unused soil from each sample that wasn’t used in the extractions or for obtaining characteristics of the soil such as soil moisture or nutrient levels (such as carbon, nitrogen and phosphorus).