McMurdo LTER Data Sets
STREAMS
One of the most important measurements for understanding watershed processes is streamflow as a function of time. In the McMurdo Dry Valleys, streamflow measurements become even more important because of the importance of the brief summer melt period to the ecosystem. Measurements of stream flow during the LTER have indicated a decrease in total discharge over time. Numerous ephemeral streams link the glaciers and lakes within the dry valleys for six to ten 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 now has in place an extensive network of gauging stations where streamflow is continuously measured throughout the austral summer. During the 1993-94 and 1994-95 field seasons, LTER scientists focused efforts on determining the influence of stream channel characteristics on stream flow and annual water budgets for lakes in Taylor Valley. Their results show that there are interannual variations in relative flow even among streams where stream length and location in the basin are similar. They also found that longer streams have generally higher concentrations of major ions due to greater interaction with the hyporheic zone. The 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. 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. 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. Studies by LTER scientists show that the abundance of algae and mosses in dry valley streams appears to be controlled by geomorphology or gradient and flow conditions. Studies also show that algal species are spatially segregated across the stream channel according to their adaptations to fast, slow, or marginal stream environments.
Stream Locations, Measurement Sites:
Stream Hydrology:
Stream Biology:
Stream Chemistry:
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