Table 2.
Average and range of values of the different variables measured in the SML and surface plankton of the studied lakes.
| Variable | SML | Surface | P (paired t-test) |
|---|---|---|---|
| PHOTOTROPHIC PICOPLANKTON | |||
| Total PPP abundance | 7.1 103 (0.3−18.9) | 6.3 103 (0.5−12.6) | NS |
| Picocyanobacteria | 2.4 103 (0−13.0) | 1.3 103 (0−9.5) | 0.02 |
| Small eukaryotes | 4.7 103 (0.3−13.7) | 5.0 103 (0.2−10.8) | NS |
| Ratio small eukaryotes:cyanobacteria | 150 (0-650) | 238 (0−800) | 0.03 |
| Number of diff. PPP populations | 4.1 (1−7) | 4.5 (2−7) | NS |
| Number of diff. picocyanobacterial pop. | 0.8 (0−2) | 0.6 (0−2) | NS |
| Number of diff. small eukaryotes populations | 3.3 (1−5) | 3.9 (2−6) | 0.04 |
| HETEROTROPHIC PICOPLANKTON | |||
| Total heterotrophic prokaryotes | 1.0 106 (0.3−2.0) | 0.8 106 (0.3−1.8) | 0.03 |
| NADS-Live prokaryotes | 5.0 105 (0.7−9.9) | 4.9 105 (1.1−12.1) | NS |
| NADS-Dead prokaryotes | 5.1 105 (1.8−11.2) | 3.2 105 (0.8−5.4) | 0.01 |
| HNF abundance | 3.0 103 (0.9−8.8) | 2.0 103 (0.9−5.7) | 0.02 |
| Ratio Total heterotrophic prokaryotes:HNF | 482 (63−1297) | 491 (135−1122) | NS |
| CTC positive prokaryotes | 3.7 104 (2.1−6.1) | 2.8 104 (1.6−5.8) | 0.01 |
| Prokaryotic heterotrophic act. (leucine inc.) | 9.5 (1.4−29.0) | 27.9 (7.4−61.4) | <0.01 |
| Cell-specific prokaryotic activity | 9.9 (3−31) | 36.0 (16−64) | <0.01 |
| % Live prokaryotes | 49 (22−70) | 59 (44−82) | <0.01 |
Abundances in cells ml−1. Bacterial activity in pmol Leu ml−1 h−1 and cell-specific activity in amol cell−1 h−1. Averages and the statistical comparison of the picophytoplankton (PPP) abundance data do not include Bassa de les Granotes, an obvious outlier. All variables were log transformed to achieve normality prior to the paired t-test.