The importance of Protozoa in controlling the abundance of planktonic algae in lakes
ABSTRACT Apart from ciliates, there are other protozoans which can form an important element in the herbivorous zooplankton of lakes.The protozoans discussed in this paper feed on colonial algae. They can greatly reduce the numbers of certain Chlorophyta in Windermere, Esthwaite Water and Blelham Tarn, lakes in the English Lake District.A very short period, often 7–14 days, can suffice for the destruction of more than 99% of an algal population.Experiments with a species of Pseudospora showed that it would only ingest one out of six green algal species, although, in nature, Pseudosporae which are morphologically similar to this species have been observed in all these algae.The importance of such protozoans, and of parasitic fungi, has been underrated or neglected in studies of the quantitative relationships between primary and secondary production in the plankton.
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ABSTRACT: This study provides data to define an efficient biocide-free strategy based on zosteric acid to counteract biofilm formation on the membranes of submerged bioreactor system plants. 16S rRNA gene phylogenetic analysis showed that gammaproteobacteria was the prevalent taxa on fouled membranes of an Italian wastewater plant. Pseudomonas was the prevalent genus among the cultivable membrane-fouler bacteria and Pseudomonas putida was selected as the target microorganism to test the efficacy of the antifoulant. Zosteric acid was not a source of carbon and energy for P. putida cells and, at 200 mg/L, it caused a reduction of bacterial coverage by 80%. Biofilm experiments confirmed the compound caused a significant decrease in biomass (-97%) and thickness (-50%), and it induced a migration activity of the peritrichous flagellated P. putida over the polycarbonate surface not amenable to a biofilm phenotype. The low octanol-water partitioning coefficient and the high water solubility suggested a low bioaccumulation potential and the water compartment as its main environmental recipient and capacitor. Preliminary ecotoxicological tests did not highlight direct toxicity effects toward Daphnia magna. For green algae Pseudokirchneriella subcapitata an effect was observed at concentrations above 100 mg/L with a significant growth of protozoa that may be connected to a concurrent algal growth inhibition.International Journal of Molecular Sciences 01/2014; 15(6):9497-9518. · 2.46 Impact Factor
- Journal of Plankton Research 01/1986; 8(2):393-398. · 2.44 Impact Factor
Article: MicroalgacultureCritical Reviews in Biotechnology 09/2008; 4(3):369-438. · 7.84 Impact Factor