| Abstrakt: |
We surveyed 14 ponds in 1999 and 28 ponds in 2000 to better understand the basic limnology of alpine ponds and to predict how the planktonic and epipelic (sediment-living) algal communities may respond to nutrient deposition and climate change. Based on nitrogen to phosphorus ratios, nitrogen limitation is likely common in these alpine ponds, which makes them particularly susceptible to current increases in atmospheric N deposition. Regression and redundancy analysis (RDA) showed phytoplankton abundance and community composition was best explained by total phosphorus (TP), pH, and conductivity. Epipelon abundance was best explained by nitrite plus nitrate and community composition was best explained by TP and dissolved organic carbon (DOC) in addition to nitrite plus nitrate. Some of these chemical variables, DOC, pH, and conductivity, have been linked to climate in alpine ponds and lakes and in low elevation lakes, which suggests alpine ponds may be sensitive to climate change. However, because we found interannual variability in the environmental-algal relationships, several years of study may be required in order to make realistic predictions on how algal communities will respond to increasing nutrient deposition and climate change. [ABSTRACT FROM AUTHOR] |
