Population dynamics of autotrophic picoplankton in relation to environmental factors in a productive lake |
| |
| Authors: | Télesphore Sime-Ngando |
| |
| Institution: | (1) CNRS-URA 1944, Biologie Comparée des Protistes, Université Blaise Pascal (Clermont-Ferrand II), les Cézeaux, F-63177 Aubière Cedex, France |
| |
| Abstract: | Spatial and seasonal fluctuations in autotrophic picoplankton (APP) abundance in a eutrophic, dimictic lake (Lake Aydat, France) were measured concurrently with a variety of environmental variables. Cell number ranged from 0.03 to 2.36×106 cells·ml–1 (highest concentrations were >5-fold higher than in oligotrophic lakes) and averaged 24 ± 7% of total picoplankton abundance (APP + heterotrophic bacteria). APP abundance (1) peaked in spring simultaneously with heterotrophic flagellate and ciliate densities, (2) decreased during the nitrogen-limited and summer stratification period, and (3) increased with fall turnover. In summer-autumn, the contribution of single-cell eukaryotic (up to 66%) and colonial prokaryotic (18%) forms to total abundance peaked in the bottom waters. Multivariate regression analyses suggest that >40% variance in APP number changes may be explained by ciliate abundance (at 0–4 m depth-range), heterotrophic flagellate number and oxygen concentration (5–9 m), and ciliate carbon biomass (10–14 m). The model accounting for changes in heterotrophic bacterial abundance (5–9 m) indicates chlorophylla concentration (r
2=58%) and ciliate abundance (r
2=34%) as dominant covariates. The data presented here suggest that micrograzers control APP abundance in Lake Aydat. |
| |
| Keywords: | Lake autotrophic picoplankton microzooplankton |
| 本文献已被 SpringerLink 等数据库收录！ |
|
