Crater Lake Limnological Studies Final Report
Long-Term Monitoring Program
The 10-year limnological study of Crater Lake revealed many of the components and processes important to lake clarity and to the dynamics of the lake ecosystem as a whole (Table 1). Although the relative importance of these components was well documented in many instances, many questions were generated which could not be addressed in sufficient detail within the scope of the program. This shortfall poses a problem because several human-related activities were identified which may have negative impacts on the lake (Table 2). Crater Lake is a unique lake from a global perspective, and it is highly valued both nationally and internationally. Responsibility for management of such a system should be a priority. Furthermore, the long-term data set that now exists for the lake has great scientific value for understanding processes that are common to all aquatic systems. Few pristine lakes have received such extensive study. The scientific value of these data will grow immensely if additional data can be added. The National Park Service, the agency charged with maintaining the pristine condition of the lake, must regulate human activities within the context of existing information and regulations, and simultaneously support the collection of additional information. Long-term monitoring of selected features of the lake system coupled with special short-term studies is needed for additional information for management and scientific purposes.
|
Component or Process |
Relative Importance to Understanding Lake Clarity |
Relative Importance to Understanding the Lake System |
Level of Knowledge |
|---|---|---|---|
|
Lake level |
Moderate |
Moderate-High |
Moderate |
|
Water budget |
Moderate |
High |
Moderate |
|
Depth of surface mixing in winter |
High |
High |
Moderate |
|
Thermal stratification |
High |
High |
Moderate |
|
Depth of surface mixing in fall |
High |
Moderate |
Low |
|
Abiotic particles: mudslides, avalanches, runoff & storm events |
High |
Low-Moderate |
Low |
|
Nutrient budget |
Moderate |
High |
Moderate |
|
Hydrothermal inputs |
Low |
High |
Moderate |
|
Organic detritus |
Moderate |
High |
Moderate |
|
Nutrient upwelling from the deep lake |
High |
High |
Moderate |
|
Spring 42 nitrate – N |
Low |
Low |
High |
|
Atmospheric deposition |
Moderate |
High |
Moderate |
|
Particle flux |
Moderate |
High |
Moderate |
|
Boat and automobile Emissions/Petroleum wastes |
? |
? |
Low |
|
Phytoplankton production dynamics |
Moderate-High |
High |
Moderate |
|
Zooplankton production dynamics |
Low-Moderate |
High |
Low-Moderate |
|
Benthic flora (production & nutrient dynamics) |
Low |
High (?) |
Low |
|
Benthic fauna (production dynamics) |
Low |
Moderate |
Low |
|
Fish production dynamics |
Low-Moderate |
High |
Low-Moderate |
|
Issues of Concerns |
Processes or Components Impacted |
Level of Understanding of the Impact |
|---|---|---|
|
Atmospheric deposition |
Nutrients |
Moderate |
|
Automobile and boat emissions |
Carbon particles |
Low |
|
Contamination of Spring 42 |
Nitrate-N concentration |
High |
|
Road and parking lot runoff |
Release of petroleum products |
Low |
|
Global climate change |
Depth of surface mixing |
Low |
|
Introduced species: |
Benthic food web |
Low |
|
Rainbow trout |
Predation on: |
Low |
|
Kokanee salmon |
Predation on: |
Low |
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