Decomposition of Lake Phytoplankton. 2. Composition and Lability of Lysis Products

• Published in: Oikos 1986, Vol.46 (1), p.45-50
• Main Authors: Krog, Gudrun F., Hansen, Lisbeth, Søndergaard, Morten
• Format: Article
• Language: English
• Subjects: Algae; Amino acids; Carbon; Chemical composition; Diatoms; Freshwater; Low molecular weights; Molecular weight; Molecules; Phytoplankton; Polysaccharides
• ISSN: 0030-1299; 1600-0706
• DOI: 10.2307/3565378

The lysis process of phytoplankton was followed in 24 h incubations in three Danish lakes. By means of gel-chromatography it was shown that the dissolved carbon leaching from different algal groups differed in molecular weight composition. Three distinct molecular weight classes (> 10,000; 700 to 10,000 and < 700 Daltons) leached from blue-green algae in almost equal proportion. The lysis products of spring-bloom diatoms included only the two smaller size classes, and the molecules between 700 and 10,000 Daltons dominated. Measurements of cell content during decomposition of the diatoms revealed polysaccharides and low molecular weight compounds to dominate the lysis products. No proteins were leached during the first 24 h after cell death. By incubating the dead algae in natural lake water, it was possible to detect a high bacterial affinity towards molecules between 700 and 10,000 Daltons, although the other size classes were also utilized. Bacterial transformation of small molecules to larger molecules could be demonstrated. /// Процесс лизиса фитопланктона наблюдали при 24-часовой инкубации в трех озерах Дании. С помоцью гелевой хроматографии было показано, что растворенный углерод, выщелоченный из разных групп водорослей, различался по составу молекул с разньм весом. Три четко различаюцихся по молекулярному весу класса соединений (>10000; 700-10000 и