We know a lot about microbes already. We know that they produced almost all of the world's free oxygen so that later, complex organism could evolve. They help us digest our food. They break down waste products. But there's still a lot we don't understand about microbes.
We can see nutrients going into this ecosystem dominated by microbes, and we can see other nutrients come out, but what happens in between? Who is sharing iron? How does sulfur get from point A to point B? What factors limit their productivity?
Microbes need buddies. One kind of microbe uses a lot of one nutrient, but then their waste products become food for someone else. What factors makes each kind of microbe more or less productive? Is it their genes? Is it environmental factors like amount of light, or amount of salt?
If we can understand these relationships, we can apply this knowledge to more complex ecosystems in the world. In other places, things get complicated quickly with multicellular plants and animals and pesky things like the water cycle. Here, its just the microbes, sealed off from the world by 3+ meters of ice, hanging out with their buddies.