Seasonal changes in phytoplankton populations and related chemical and physical characteristics in lakes in Loch Vale, Rocky Mountain National Park, Colorado
McKnight D, Brenner M, Smith R, Baron J. 1986. Seasonal changes in phytoplankton populations and related chemical and physical characteristics in lakes in Loch Vale, Rocky Mountain National Park, Colorado. U.S. Geological Survey (USGS) Water Resources Investigations Report. Water-Resources Investigations Report 86-4101. USGS. Denver, CO
Phytoplankton populations and related chemical and physical characteristics were monitored in Sky Pond and The Loch in Loch Vale, Rocky Mountain National Park, Colorado, during the spring, summer, and fall of 1984, as part of a long-term study to determine the effects of precipitation chemistry on biogeochemical processes in high-elevation lakes and drainage basins that might be adversely affected by acid rain. Three distinct periods in the sequence of phytoplankton populations were observed: (1) A spring population peak that was dominated by diatoms, mainly Asterionella formosa, and some green algal species; (2) a midsummer population minimum, when the diatom populations decreased 10- to 100-fold; and (3) a fall population peak, which was almost unialgal, dominated by a filamentous blue-green alga, Oscillatoria limnetica. The spring diatom peak could have been caused by the two-fold increase in nitrate concentration during the spring snowmelt. The midsummer diatom decrease most likely was caused by zooplankton grazing, or photoinhibition, or both, rather than by phosphate depletion because orthophosphate concentrations increased at this time. It is further hypothesized that the rapid flushing rates during spring are an important factor regulating phytoplankton populations in these lakes.
- Type
- Published Report
- Authors
- McKnight, Diane; Brenner, Mark; Smith, Richard; Baron, Jill
- Date of Issue
- 1986
- Publisher
- USGS
- Units
- ROMO , WRD
- Keywords
- aquatic environment, Aquatic Habitats, Aquatic Sciences, Clemson, Contaminant, Water resource, WRBIB