Holiday Field Work

Christmas was very festive here at Rothera Station. One Christmas Eve, everyone on station gathered together after dinner to sing carols, drink mulled cider, and eat mince pies and other holiday goodies. Christmas Day was a day off for most people. Uffe and I did a bit of work in the lab before the big Christmas dinner. The chefs put together an excellent five-course meal using REAL fresh vegetables, complete with traditional British krackers and Christmas pudding.

Boxing Day (the day after Christmas) was also a day off for most people, but some of us went to our next field site on Jenny Island.

Jenny Island has not been visited very often, because it is outside the typical boating range in uncharted waters. (We were able to go because there's a large vessel in the area that would've rescued us in an emergency.) It was fun for us to be able to go! As it turns out, Jenny Island was an excellent place to sample soil. We found very large beds of moss and grass that provided great soil samples. You can see some of the moss bed in the picture above. We got a lot of great samples, which we are now processing in the lab.

There are a lot of elephant seals on Jenny Island. This one was very curious about our boat and kept shoving it. Elephant seals can weigh a couple tons, so they are quite capable of swamping the boat! One person always had to stay near the boats to shoo them away if they caused a problem, which made this elephant seal very unhappy!

Marine biology

There are a lot of neat creatures living in the ocean around Antarctica: not just whales, seals, and penguins! There’s quite a diversity of invertebrates (animals without backbones) living on the ocean floor. We call these benthic invertebrates. (“Benthic” means they live on the bottom.)

There are several scientists at Rothera who study these benthic invertebrates, and they shared some of their animals with me. There are some animals you are probably familiar with: sea stars (or starfish), brittle stars, sea cucumbers, and anemone. There are also other really neat animals that you may not know, like feather stars, sun stars (big sea stars with lots of arms), sea lemons (a type of snail), and nudibranchs (a type of mollusk). You can see many of these animals in these pictures I took from the marine water tanks in the lab.

Sun star with a feather star in the background

Sea star, with a sea cucumber to the right

Sea lemon, sea star, and brittle star

Nudibranch

Terri, one of the marine biologists, tells me that they’ve learned that these benthic invertebrates are less abundant in the water here than they used to be. With the increasing temperatures from climate change, there is less ice over the water. Specifically, the “fast sea ice” is declining. Fast ice is the ice that’s thick and fastened to land, so it doesn’t float or drift around. It holds everything floating on the water in place, including icebergs. Fast sea ice used to cover the ocean for around 8 months of the year. Now, because it’s warmer, the fast sea ice is only around for 2 months of the year. Without the fast ice, ice bergs can float around and move more than they used to. The bottoms of ice bergs are very deep and, here along the coast, they scrape the bottom of the ocean. The benthic invertebrates at the bottom of the ocean can’t run away from the ice bergs. Because most of them have soft bodies without shells, and get smashed by the moving ice bergs. That is one of the many changes this region is experiencing due to climate change!

Is there soil in Antarctica?

Most of the scientists that work from Rothera Station study either ice or the ocean. There are not many soil scientists. One of the questions we get asked a lot is, “There’s soil here?” Yes, there’s soil in Antarctica!

Soil is formed from the weathering of rock, which breaks it down into small particles. Those small particles get colonized by biology. In Antarctica, it’s easy to see that rock gets weathered by the wind. There are also organisms living here, so that means we have soil! Many people don’t think it’s soil, because it looks more like sand to them. The soil at home has more noticeable plants and decomposition happening. But in Antarctica we have lichen and moss growing on the soil, and a lot of microscopic organisms in the soil. Bacteria, fungi, nematodes, Tardigrades, and other microscopic invertebrates live here, so there’s biology even if you can’t see it without a microscope!

 This photo captures the formation of soil in Antarctica. It starts off in the crevices of rocks, for example. The biology turns that weathered material into soil, and over time it can build up and turn into a larger expanse of soil like we see at Mars Oasis.

Next field site: Anchorage Island

Yesterday we took a boat out to our next field site at Anchorage Island, which is an island near Rothera Station. So it is the farthest north of the sites we've sampled so far.

We collected soil in the same way we collected from our previous sites, by taking replicate soil samples from beneath different above-ground growth types. In addition to moss and algae, we were able to take soil from beneath grass. The reason Anchorage Island is interesting is because it's one of the most southern sites along the Antarctic Peninsula where you can find grass.

There's only one species of grass in Antarctica, and it mainly only grows in the more northern, less cold areas. The species of grass is Deschampsia antarctica, commonly known as Antarctic hairgrass. Here's what the grass looks like at Anchorage Island. Until recently, it was covered with snow, so it's still mostly brown, but soon it will perk up and turn green!

I think sampling the islands is fun, because we get to take a boat out on Marguerite Bay. Here's what it looks like riding back to Rothera Station from Anchorage Island on the boat:

Lab Work

Now that we’ve collected soil samples, we need to extract and identify the organisms living in the soil. We also need to measure the chemistry of the soil to understand the organisms’ habitat. For the past few days, we’ve been working quite a lot in the lab.

We first preserve part of the soil to measure the bacteria and fungi back at home in the U.S. We separate some of the soil into a vial and add a solution that preserves the bacteria and fungi. These vials will be sent home and analyzed there. We will use microscopes to count the number of bacterial and fungal cells in each sample, and we will find out what species they are using their DNA.

From another portion of soil, we extract the nematodes that live in the water around the soil particles. This is done by wrapping the soil in a tissue and placing it on a rack that’s submerged in water. The nematodes float out of the soil into the water, then drop to the bottom of the dish. We’ll collect the nematodes from the bottom of the dish and look at them under a microscope to identify them. Other animals also live in the water around soil particles, such as Tardigrades and rotifers, which we may find in these samples.

We also extract larger invertebrates from the soil. These are removed from the soil using two methods. One of the methods uses heat created by a light bulb. We place soil or moss on a funnel and attach a light bulb. (You can buy official versions, but we made our own out of drink cans, gauze, and Christmas lights!) We gradually turn up the dimmer switch over a few days, which heats and dries the soil. The organisms try to move deeper in the soil to stay cool, which makes them fall down through the funnel into our vial. So far, we have found a lot of mites and springtails in these samples.

We also plan to measure the chemistry of the soil. We want to know how much nutrients are available in the soil (like nitrogen, phosphorus, and carbon). We want to know the pH of the soil and how salty it is. All of these are important for the organisms living in the soil. If it’s too salty, too acidic, or if nutrients are too low, they may not be able to survive. We expect to find that the different types of growth on the soil (moss, lichen, algae, etc.) house different communities of organisms because they create different soil chemistry.

First Field Trip

We have returned from a 9-day trip out to a few different field camps. We were finally able to start collecting our soil samples!

The first place we went is called Mars Oasis. To get there, we flew on a Twin Otter airplane that landed on Utopia Glacier. We camped on the glacier for 6 days. Here’s a picture of the glacier that we landed and camped on. We set up our camp near the dark spots towards the back, where the plane had enough space to land and there were no known crevasses.

We skied from our campsite to Mars Oasis at the base of the glacier, which is an area of exposed soil under some cliffs. That’s the hunk of land sticking out at the left of the picture. This is where we collected our first set of samples!

Our goal is to collect soil from beneath different types of plant and fungal growth. We want to know how different above-ground organisms influence the microscopic organisms living in the soil. We collected soil from beneath moss, lichens, and algae. We also collected bare soil with no above-ground growth to compare these to. When we extract the bacteria, fungi, and invertebrates (like nematodes and mites), we will find out whether the soil community is more abundant or more diverse under particular types of growth.

An area of mixed lichen, algae, fungi, and moss growth

 We collect five soil samples from beneath each growth type, so we collected 20 samples total from Mars Oasis. Five samples gives us replication. That way, we know that we are measuring a real pattern. If we only took one sample from under moss and found a large amount of soil diversity, we wouldn’t know if it was because of the moss or if it just happened to be that way by accident. If we find a large amount of diversity under all five moss samples, we will be more certain that moss has a big influence over soil diversity.

We also traveled to a second field site at Sky Blu. This site is much farther south on the mainland of the continent, and is almost completely covered by ice. The only soil available is from the tops of large mountains that poke through the ice. These mountain tops are called nunataks. We sampled soil from the nunataks as well, so that we can compare how above-ground growth influences soil organisms at multiple sites.

Sky Blu has a permanent camp, so we were able to stay in shelters instead of camping in tents. It was -14°C while we were there. I’ve been traveling with a bear from Mrs. Metcalfe’s class in Phoenix, AZ. Here he is at Sky Blu camp with one of the nunataks in the background.

 Now that we have collected our first set of soil samples, we have a lot of work to do in the lab. We need to extract the organisms we are interested in measuring, and we need to measure the chemistry on the soils. I will tell you more about that in my next post. However, right now, I need to get back to work in the lab!

Seal Watch

We STILL can't get to our field sites. Mars Oasis is too cloudy for the plane to  land. Maybe tomorrow!

Instead, today I helped the marine biologists. There are many marine biologists at Rothera Station that study the invertebrates living on the bottom of the ocean. To do their research, they have to scuba dive in the bay that borders the research station. The cold water is their first danger, so they wear protective suits. There are a couple other dangers they must avoid, which are leopard seals and orcas (killer whales). Humans in dive suits underwater can easily be mistaken for a seal, penguin, or other tasty morsel that these animals eat. Because they have attacked humans before, the marine biologists can't dive if one is in the area

Safety rules require that someone be on what we call "seal watch". That person scans the area for leopard seals and orcas for 30 minutes before the diver gets in the water, and also while they're diving. If one is seen, the diver must immediately leave the water and cannot go back in for four hours after the animal was last seen. There's nothing we can do to remove the animal if one is seen, so the divers have to wait until they decide to leave, which could be days!

The pier at Rothera Station

So this morning I was on Seal Watch for the marine biologists. I stood at the end of the pier and watched the bay for wildlife with a pair of binoculars. It's pretty nice job, since it was sunny, with no wind, and relatively warm! I didn't see any seals or whales at all, so the marine biologist was able to complete her work.