Greetings from the Dry Valleys of Antarctica! The McMurdo (MCM) Long-Term Ecological Research site is located in the middle of an extreme polar desert, and is regarded as the end-member of the LTER program. The Dry Valleys are representative of the 2% of Antarctica that is ice-free, and are also considered one of the harshest environments on the planet because of low temperatures, scarce precipitation, and 24-hour darkness over the winter months. However, the terrain is not completely barren, and for the past 20 years the MCM LTER has been monitoring lake levels, streamflow, soil transects, and glacial melt in order to better understand this harsh environment.
Our group, the “Stream Team”, arrived at McMurdo Station in late October, and has since been preparing for our upcoming field season by washing sample bottles at Crary Laboratory and completing the numerous training exercises necessary to conduct safe and responsible research in a pristine environment. The next few months will be spent at our camp in the Dry Valleys, and over the next couple of weeks we will be repairing and readying equipment so that we will be ready to study streamflow later in the austral summer. This includes utilizing helicopters and ATV’s to visit each of our stream gauging stations, which are located at the outlet of each stream on the valley floor. These stream gauges will record the amount of water that is flowing though the streams during the flow season, which can be anywhere from several weeks to several months out of the year.
Many people are surprised to hear that there are lakes and streams on the continent of Antarctica. Not only do they exist, but they are quite special compared to water bodies found elsewhere in the world. For example, the lakes that the MCM LTER studies have year-round ice cover, and many of them are closed-basins, meaning that they do not have an outlet. The streams are also unique in that they do not have any vegetation along the sides and are fed almost exclusively by glacial melt. By measuring water as it travels from the glacial source, through the streams, and finally into the lakes, we can get a glimpse into the water cycle of the Dry Valleys, and compare this season’s melt with seasons past.
While there are no higher plants or animals in the Dry Valleys (the largest organism is the nematode), there are some very interesting microbial communities in the soils, lakes, and streams which we study and still have much to learn about. Liquid water is the limiting resource for many of these communities, and while some may be dormant for the Antarctic winter, many are reactivated during the summer when water becomes available. For example, the microbial communities in the streams, which persist throughout the year as a dried crust, are re-hydrated by streamflow and resume photosynthesizing soon after. In addition to physical measurements, we will additionally be sampling some of these organisms to better understand life at its limits on Earth.
This year, we have multiple projects planned along with our usual monitoring, which should provide a nice look into the ecology of these extreme systems. We look forward to sharing more about our research later in the season!
Tyler Kohler, Graduate Student, University of Colorado at Boulder