Happy New Year from the Stream Team!
Stream visits are the reason we are in Antarctica. So now that the streams are flowing and the holidays are out of the way, stream visits will be keeping us busy for next month or so. There are stream gauges at about 15 different sites in the dry valleys, and many more streams are not gauged but are monitored for water quality. As we have mentioned before, these gauges consist of a big wooden box full of gadgets that essentially record the resistance it takes to pump a bubble of nitrogen out, which is proportional to the height of the water column above. However, the trick is to know the relationship between this value and the amount of water that is actually flowing in the stream at a given moment. To do this, we make manual discharge measurements.
Manual measurements are done either with a pygmy meter (an updated version above) or a portable flume (below). The pygmy meter is an elegant tool that requires you measure the depth and the speed of the water by counting the rotations of a wheel at the bottom of a staff along different parts of a transect. By knowing the amount of water passing through the resulting “little rectangles”, one can calculate the discharge for the entire stream. The flume on the other hand uses marks on the sides to measure how much water is passing through at a given moment. The portable flume can therefore be a much quicker method, but can only be used at low stream flows.
Another important aspect of a stream visit includes taking water samples. We collect small amounts of water in bottles, then take these samples back to camp where they are filtered and preserved until they can be sent back to McMurdo for analysis. Many different tests are done, such as measuring the amount of dissolved organic carbon, nitrogen, and phosphorus. Filtering the particulates out of water samples generally takes a fair amount of time once back at camp. Good thing we washed all those bottles at the beginning of the season!
We also collect “other kinds of water” while in the field. Since the Antarctic policy is to leave no trace, all waste is collected and shipped off continent. This applies to waste generated while sampling streams, and when natures calls, you better have a Nalgene bottle ready, because the nearest outhouse may be a helicopter ride over pristine glaciers and rocky peaks away!