Case Study
Alaska: Monitoring Mixing Dynamics and Water Quality

Application Type:
Monitoring lake heat content and water column mixing

Contributors Include:
Sally MacIntyre, Bridget Benson, J.P. Fram; University of California Santa Barbara and Arctic LTER.
Christie Haupert, University of Alaska Toolik Lake Field Station
George Kling, University of Michigan and Arctic LTER

Products Used:
CR10X (Now the CR1000), T-Chain

Toolik Lake is 130 miles south of Prudhoe Bay in Northern Alaska and is classified as a dimictic lake, meaning a lake that undergoes two mixing periods during the Spring and Fall. The lake is thermally stratified during the summer as colder denser water sinks to the bottom, while warmer water sits on top. During this period, the thermocline is formed and lake turnover will not occur until later in the year when winds pick up and the solar radiation has decreased.

Researchers are interested in monitoring the thermal stratification in Lake Toolik as well as its mixing dynamics in order to look at the movement of nutrient flux (how nutrients flow and are processed in a lake). Nutrient flux is critical when studying ecosystem processes. Studies have shown that during a three week warming period at Toolik, after ice has disappeared from the surface, vertical mixing was detected near the lake’s slopes providing inorganic nitrogen to phytoplankton. Phytoplankton production relies upon the inorganic nitrogen movement within the lake.

A Temperature Chain (T-Chain purchased from Precision Measurement Engineering, Inc.) was used in conjunction with a Campbell C10X data logger. The Temperature Chain and logger are designed to collect real-time continuous data of temperature with an accuracy of +/- .01 degrees C.

This instrument can be designed with temperature, dissolved oxygen and Photosynthetically Active Radiation (PAR) sensors. Each chain is custom designed according to desired specifications.