Crater Lake is the deepest lake in the United States (580 m) and one of the clearest and most pristine lakes in the world. Climate change threatens to alter the fundamental lake processes in Crater Lake that make it so awe-inspiring to the public. A USGS-NPS partnership funded study has shown that warming fall-winter air temperatures at Crater Lake will likely reduce the frequency of deep-water mixing events (an exchange of water between the surface and depths below 300 m) or halt them all together due to warming water temperature.

In this study, we will address the questions:

• How will such a change in the frequency of deep-water mixing events affect water clarity?
• What is the effect of climate change on the timing of the onset of stratification and the depth of summer thermocline?
• How do these two consequences of climate change interact to determine effects on water clarity?
• How will such a change in the frequency of deep-water mixing events affect deep-water oxygen concentration?