Sunday, January 4, 2009

Now where was that?

The plants and animals that live in the Dry Valleys are very small. Because they are so small, they are often difficult to locate, and even more difficult to find a second time.

This picture shows how closely you have to look to find the mosses that we study.

There are also no road signs pointing us in the direction of our research sites. We study certain spots in the field during one research season and try to get back to those same locations the next year. This is challenging because there are very few land features that we can use to remember a certain location and some things change from year to year. The streams are fed by melted snow, so they change depending upon how much snow falls during the winter and melts in the summer. This stream might have looked completely different last year, so finding a particular bend in the stream is nearly impossible.

Because of these navigational challenges, we use a GPS to help us find places in the Dry Valleys.
GPS stands for Global Positioning System. It uses satellites orbiting the earth that transmit signals, which enable GPS receivers to determine their current location. A GPS tells you your location in latitude and longitude coordinates. When we want to be able to find a certain spot again, we record the latitude and longitude coordinates so that we can later return to that exact location using the GPS.

Here's a picture of Elizabeth using a GPS to record the coordinates of a study site. If she wants to come back later, all she has to do is tell the GPS to find those coordinates and it will point an arrow in the direction we need to walk to get there. It also tells you distance.

A GPS isn't perfect. Sometimes we have a really hard time finding a spot using the coordinates a GPS gives us. It is often about 10 meters off, which is a lot when your study subject is only 1 centimeter tall. But the GPS is a very useful tool and we are very happy that it's in our scientific toolbox!