Dry Valley Critters

It may be surprising that a continent so famous for its seals and penguins would not have any living in the dry valleys. While they don’t live here, seals and penguins do get lost and wonder into the valleys occasionally.  This generally doesn’t end well for the critter, and penguin and seal mummies are found all over the valleys, sometimes in quite surprising places. These can be very old, and some of them have signs of being picked apart by the Skua, which is a sea bird that occasionally flies through the valleys and is known for, among other things, its ability to steal a sandwich out of your hand.

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While there are no animals or plants living in the dry valleys (and the biggest creature you are likely to come across is a nematode), microbial life is abundant in the soils, lakes, and ponds. The Stream Team is particularly interested in the microbial mat communities that grow on the bottom of the streams. These mats are mostly made up of cyanobacteria, which hold the communities together. On the top of these mats is a protective layer of orange or black pigment that shades the mat from the harsh Antarctic radiation. Below this may be a whole host of creatures such as diatoms, tardigrades, and bacteria found in different layers of the mat.

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As part of the long-term ecological research (LTER) monitoring, these microbial mats are sampled from the streams in early to mid-January. This is done by taking a known area of the mat from the stream bottom with a brass cork borer for each type of mat present. This sampling has been done almost every year since the early 1990’s at transects across certain streams in order to look for changes occurring in a particular stream over time. What we now know is that some streams really don’t change all that much from year to year, while in other streams the algal mats have completely disappeared.

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Understanding the environmental conditions that control the abundance and distribution of these mats is important for making sense of observations such as these, but also for similar mat communities in other parts of the world. Perhaps more interestingly, these mats may tell us what primitive life on earth might have been like, as well as in other extreme habitats. Additionally, since old streambeds have recently been found on Mars, it is interesting to think that if life has ever existed there, it may have been very similar to our Antarctic mats. 

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