Antarctic gardening

We have been busy working in the field to set up our main experiment. This is an important way that we can study the plant-soil feedbacks during succession. How do you know for sure that adding a plant changes the soil? You add a plant to bare soil, and see how the soil changes! So, we are starting a "transplant" experiment. 

We are taking grass, moss, and algae from the surrounding area and planting them into bare soil in an early succession zone. (So, we are "transplanting" the plants from one area to another.) We sampled the bare soil before adding plants, so that we can understand the early succession soil before plants colonize.

Here I am, sampling the bare soil in one of our soon-to-be transplant plots.

We will measure the bacteria, fungi, and invertebrates in the bare soil. We will also measure the amount of nutrients and other chemical properties that are important for sustaining life. That will give us a picture of the soil before plants arrive.

Then, we did a little gardening! A couple days ago, we moved tufts of the Antarctic hairgrass into our bare soils. 

Dr. Hannah is happy to plant her grass.

Today we moved two different species of moss. Not all moss are the same! Some mosses are pleurocarps, like Sanionia on the left side of the photo. They spread out on the surface of the soil, growing overtop of what's below them. They make a mat that you can peel up from the ground, almost like a carpet. (They can also regenerate from pieces of the mat that have blown in the wind, and survive on top of rocks, making them good pioneers in early succession!) Other species, like Polytrichastrum on the right side of the photo, are acrocarps. They grow into the soil. Their rhizoids (the root-like part of the plant) intertwine into the soil like turf. Those we have to move in tufts like grass.

Sanionia (the pleurocarp) is being laid down on the left. Grass is in the middle, and Polytrichastrum (the acrocarp) is on the right.

We have one more plant left to move, which is the algae. We will hopefully be able to finish that tomorrow, and our experiment will be set up!

As the plants grow, they will begin changing the soil. They will perhaps add nutrients, create a habitat for more soil organisms, and change the temperature and moisture of the soil. We will revisit these transplants for three years to measure how the plants change the soil as they grow. By making the same measurements as we make on the bare soil at the start of the experiment, we will see how the plants change the soil chemistry and biological community.

It feels good to have our main experiment almost completely set up!