Composition and dynamics of autotrophic picoplankton and spectral light distribution in saline lignite mining lakes of Germany

Abstract

In two saline turbid mining lakes, the seasonal dynamics of autotrophic picoplankton (APP) were investigated. APP biomass accounted for 10-96% (annual average 48%) of the total autotrophic biomass. Eucaryotic picoplankton was dominant during spring and autumn (0.4-9 l07 cells 1-5). Picocyanobacteria appeared from June to September, reaching abundances of up to 1.3 x 108 cells 1 -t. The total phosphorus content varied in the range 7-46 p~g P 1 i and chlorophyll a (chla) in the range 0.5-5.2 ~g chla 1 -I. The euphotic zone (l%-light level) extended only over the upper part of the epilimnion during the 1997 growing season. Red light (620-720 nm) was available within the water body. Blue or green light (430-580 nm) was mostly absent because of the high contents of suspended particles in lakes. This may be a reason for the occurrence of only phycocyanin-rich picocyanobacteria in the lakes investigated. This study shows that the APP constitutes a significant part of the phytoplankton in these slightly saline (6.5-8%0) turbid mining lakes. Because of their small cell size, higher uptake rates of inorganic nutrients and possibility of efficient utilization of low light intensities, they might have had an advantage for the development in the lakes investigated.

Abundance and biomass of prokaryotic and eukaryotic microorganisms coupled with environmental factors in an arid multi-pond solar saltern (Sfax, Tunisia)

“…Our results were much higher than those found in the Arabian Sea (S = 36 ‰, <7.5 × 10 3 cells · ml −1 , Garrison et al , 2000), the China Sea (North Pacific, 6 × 10 3 cells · ml −1 , Jiao et al , 2005), an Italian saline lake (salinity > 62 ‰, mean = 27 × 10 3 cells · ml −1 , Zippel & Schimmele, 1999), and Spanish salterns (0.3 × 10 3 cells · ml −1 , Estrada et al , 2004). The highest densities were recorded in ponds A16, C2-1 and M2 (salinity range: 70–200‰).…”