Phosphorus
•Limiting nutrient
•Critical levels 12 to 15 ppb
| As Kirsten mentioned earlier
in the presentation, phosphorus is the primary limiting nutrient in
freshwater ecosystems - primarily dependent on P to grow and small
concentration increases can trigger high increases in algal growth |
|
| Go over phosphorus cycle: external
sources enter in runoff (some of which taken up by phytoplankton,
some complexes with ions and settles on bottom b/c in form not usable
by plants) |
|
| also internal sources from breakdown
of dead organic matter |
|
| And internal recycling
which occurs from low oxygen levels in hypolimnion: phosphorus that was in
sediment is released increasing P levels in hypolimnion - may not be issue
when lake stratified unless turbulence draws water to surface |
|
| Mention critical levels |