The community structure and biomass of pelagic phototrophs, with a particular focus on the picoplanktonic fraction, were studied in three small, soft-water lakes in the Pomerania Lake District (north Poland). The smallest phototrophs were usually dominated by picocyanophytes, both single-celled and colonial. Picochlorophytes were less frequent, and they formed dense populations only in one lake. The nano- and microplankton included many groups of organisms, but the main groups were comprised of dinoflagellates, chrysophytes and chroococcoid and/or filamentous cyanophytes and large raphidophytes. Community structure changed significantly with depth and in all lakes remarkable differences were observed between the epilimnion and both the meta- and hypolimnion. The hypolimnion was characterized by the presence of photosynthetic green sulfur bacteria or their symbiotic consortia.
2
Dostęp do pełnego tekstu na zewnętrznej witrynie WWW
The structure of plankton in a lowland river was studied with a particular focus on autotrophic as well as heterotrophic picoplankton cells. Water samples were collected in the middle, meridional section of the Warta River in 2005. Heterotrophic picoplankton (HPP) were represented by bacteria varying in size and form, but mainly by cocci and rods. HPP abundance ranged from 3.5 × 10^6 to 9.5 × 10^6 cells m1^-1. Autotrophic picoplankton (APP) densities were considerably lower and ranged from 1.2 × 10^3 to 92 × 10^3 cells ml^-1. They were represented by prokaryotes (picocyanobacteria) and eukaryotes (small chlorophytes). Both components occurred together but eukaryotic APP usually prevailed in terms of biomass. In terms of biomass, APP seemed to play a minor role in this ecosystem in comparison with heterotrophic picoplankton.
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.