After reading my first few posts from Antarctica, you may be wondering where the science fits in with all this training and getting ready. But finally, after all of our trainings, our field season has really started: we’ve been out to the Dry Valleys and we’ve begun processing samples in the lab. Since our focus has turned toward our scientific goals, I thought this would be a good time to give an overview of the science being done in our group (affectionately known as B-507, the Wormherders, or the Dry Valleys LTER Soils Team).
The McMurdo Dry Valleys Long Term Ecological Research (LTER) project is within the LTER network, an umbrella that includes many other projects in widely varying ecosystems (Toolik Lake in Northern Alaska, where I spent a season as an undergraduate, is the location of another LTER). Long-term data sets are often hard to come by in the field of ecology, so the LTERs (many of which have been running for decades) provide valuable information about basic properties of ecosystems and how they change over time, especially in response to recent global warming.
The Dry Valleys LTER, which joined the network in 1993, provides a unique perspective on ecosystem dynamics because of its unusual characteristics as the coldest and driest LTER site. The McMurdo Dry Valleys make up the largest area of ice-free land on the continent of Antarctica; instead of being buried by miles of glacier ice, the Dry Valleys are full of steep rock slopes, barren glacial till, perennially frozen lakes, and ephemeral streams.
At first look, the Dry Valleys seem like the last place in the world to study ecology: life here doesn’t exactly stand out. On closer inspection, however, there are algae mats lining many streams, mosses growing nearby, and nematodes, rotifers, and tardigrades thriving in the soils.
The relative simplicity of the species interactions, combined with the harsh conditions and sensitivity to change make the Dry Valleys an incredibly important area to study. While much of the ice-covered Antarctic continent responds slowly to climate change, the Dry Valleys’ streams, lakes, and soils can respond rapidly.
Just like the LTER network is an umbrella, the Dry Valleys LTER itself is an umbrella, including teams focused on the streams, lakes, soils, and glaciers of the Dry Valley systems. As the Soils Team, we are interested in how the physical characteristics of the soil – such as the nutrient content and moisture level – impact the diversity and productivity of the soil communities. Part of our team (including me) measures those physical characteristics, while the other members describe the biological community (by identifying and counting the nematodes, rotifers, and tardigrades in each soil sample).
In addition to describing the communities that naturally exist in the Dry Valleys, the Soils Team is also involved in a number of long-term experiments. These experiments work by altering some physical condition of the soils and watching how the biology responds. One experiment, for instance, looks at how soil moisture and soil temperature interact to influence the soil biota. Some plots receive additional water, other plots have warming chambers, while a third set of plots receive both the water and warming treatments. In another experiment, phosphorus, nitrogen, and carbon are added to the soils. And in a new experiment the team hopes to get running next year, additional subsurface water flow is introduced through trenches dug at the top of a slope.
Although we focus on the soils, it is impossible to be out in the Dry Valleys without considering interactions among the various components of this system. The amount of moisture available to the system, for instance, is directly linked to snowfall and glacial melt.
The nutrient content of the soils is related to the rock types found within the glacial till.
This last interaction is something that I hope to investigate in greater depth – check back soon for more details!