Courtesy of the McMurdo Dry Valleys Long Term Ecological Research Program
The McMurdo Dry Valleys are the coldest and driest desert system in the world and represent 2% of the Antarctic Continent that is free of ice. This polar desert is a configuration of barren ground, alpine, terminal, and piedmont glaciers, and ephemeral streams. The high winds and bitter cold (average air temperature of -20ºC) extremely dry climate, and seasons of complete darkness or complete light create a harsh environment for life. In 1903 when Robert Falcon Scott and his party from the Discovery Expedition discovered the Dry Valleys, they referred to them as the “Valley of the Dead.” Of course now, thanks to some dedicated researchers, we know that the Dry Valleys are full of life, its just really little.
"We have seen no living thing, not even a moss or lichen."
- Robert F. Scott, 1903
"On first inspection the habitat seems as sterile as the surface of autoclaved glassware... but the trained eye, aided by a microscope, sees otherwise."
- E.O. Wilson, The Future of Life, 2002
Stream Hydrology and Ecology
Numerous ephemeral streams link the glaciers and lakes within the dry valleys for 6 to 14 weeks during the austral summer. These glacial meltwater streams recharge the dry valley lakes and are important sources of nutrients to the lakes. The McMurdo LTER has in place an extensive network of gauging stations where streamflow is continuously measured throughout the austral summer. To quantitatively describe the relationship between climate and flow in the glacial meltwater streams that feed the lakes, streamflow measurements are being used in conjunction with data on climatic conditions to develop a watershed scale model of ecological dynamics in Taylor Valley. Additionally, detailed ecological and geomorphological characteristics of 16 stream sites have been mapped using a total station and GPS equipment, establishing permanent stream sites at which the ecological responses to increased streamflow can be monitored over long time scales.
Microbial mat and moss communities are often found within and along the margins of streams in the dry valleys. Of primary interest is determining the processes that control distribution, biomass, and productivity of these communities. Despite the extreme harshness of the environment, a total of 30 taxa of cyanobacteria and chlorophytes and 45 species of diatoms are present in dry valleys streams. Diatom communities are monitored in many dry valley streams to determine ecosystem responses to seasonal and annual environmental changes.
The “Stream Team” as they are called has been actively keeping a blog and website for the past several seasons. You can also learn more about the amazing diatoms in these streams.
You can also read a great story about a seal that got lost in the Dry Valleys.
For more information contact,
Diane McKnight
University of Colorado
INSTAAR
1560 30th Street
Campus Box 450
Boulder, CO 80309-0450
Soil Ecosystems
The Dry Valley soils account for the majority of the valley surface area. Although the soils are up to five million years old, profiles are generally poorly developed. Despite the appearance of uniformity, Antarctic soils have a high degree of spatial and temporal heterogeneity in soil properties, hydrologic regimes, and biological composition, which relates to the general biological productivity of the dry valleys. The primary research goal is to understand how soil properties influence the distribution, abundance, and and how soil biota influence ecosystem processes.
Globally, there are no other soil systems where nematodes represent the top of the food chain and where food webs have such simple structure. The majority of soils sampled across the valleys (65%) support up to three invertebrate taxa (tardigrades, rotifers, nematodes), but in contrast to other ecosystems, many soils lack invertebrates. Despite their trophic dominance, species diversity of nematodes in dry valley soils is very low, and most soils are dominated by a single species, Scottnema lindsayae.
The simple food webs found in dry valley soils appear to be strongly influenced by human disturbance. The simple food chains found in dry valley soils appear to be strongly influenced by human disturbance, both directly (trampling) and indirectly (climate change). Populations of soil biota decrease drastically in walking paths, and are slow to recover. Studies on the impact of global climate change have shown that increased temperature and moisture inputs can change the structure of the food web, causing increases in an algal feeding nematode and decreases in a dominant bacterial feeder. These changes have important impacts on ecosystem processes in Antarctic soils.
For more information, contact:
Diana H. Wall
Colorado State University
Natl Resource Ecol Lab
200 W Lake Street
Fort Collins, CO 80523-1499
Ross Virginia
Dartmouth College
Environmental Studies Program
6182 Steel Hall
Hanover, NH 03755
Useful Links:
McMurdo Dry Valleys LTER
Latitudinal Gradient Project: Soil Biodiversity and Response to Climate Change - Regional comparison of Cape Hallet and Taylor Valley, Antarctic
Dr. Wall’s Soil Biodiversity Lab
Green Algae in Wharton Creek:
The algal mats in the Dry Valleys remain in a dehydrated state for most of the year until liquid water returns. Within 20 minutes of receiving liquid water, they are living and breathing again. No one knows how long these mats can remain in this state until their cells break down and they are no longer viable. A current study has just rehyrdated, or brought back to live, mats there are over 8,000 years old. Are the organisms in these mats related to the ones found in the Valleys today? Can this survival mechanism these organisms use be used by possible life on other planets, such as Mars? For more information, contact Jenny Baeseman ( This e-mail address is being protected from spambots. You need JavaScript enabled to view it )