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Title (Primary) Inorganic carbon limitation and mixotrophic growth in Chlamydomonas from an acidic mining lake
Author Tittel, J.; Bissinger, V.; Gaedke, U.; Kamjunke, N.;
Journal Protist
Year 2005
Department SEEFO; UV;
Volume 156
Issue 1
Language englisch;
Keywords mixotroph; osmotroph; Chlamydomonas; CO2 limitation; acidic mining lake; DOC
Abstract Plankton communities in acidic mining lakes (pH 2.5–3.3) are species-poor because they face extreme environmental conditions, e.g. 150 mg l−1 Fe2++Fe3+. We investigated the growth characteristics of the dominant pigmented species, the flagellate Chlamydomonas acidophila, in semi-continuous culture experiments under in situ conditions. The following hypotheses were tested: (1) Low inorganic carbon (IC) concentrations in the epilimnion (e.g. 0.3 mg l−1) arising from the low pH limit phototrophic growth (H-1); (2) the additional use of dissolved organic carbon (mixotrophy) leads to higher growth rates under IC-limitation (H-2), and (3) phagotrophy is not relevant (H-3). H-1 was supported as the culture experiments, in situ PAR and IC concentrations indicated that IC potentially limited phototrophic growth in the mixed surface layers. H-2 was also supported: mixotrophic growth always exceeded pure phototrophic growth even when photosynthesis was saturated. Dark growth in filtered lake water illuminated prior to inoculation provided evidence that Chlamydomonas was able to use the natural DOC. The alga did not grow on bacteria, thus confirming H-3. Chlamydomonas exhibited a remarkable resistance to starvation in the dark. The compensation light intensity (ca. 20 μmol photons m−2 s−1) and the maximum phototrophic growth (1.50 d−1) fell within the range of algae from non-acidic waters. Overall, Chlamydomonas, a typical r-strategist in circum-neutral systems, showed characteristics of a K-strategist in the stable, acidic lake environment in achieving moderate growth rates and minimizing metabolic losses.
ID 3844
Persistent UFZ Identifier
Tittel, J., Bissinger, V., Gaedke, U., Kamjunke, N. (2005):
Inorganic carbon limitation and mixotrophic growth in Chlamydomonas from an acidic mining lake
Protist 156 (1), 63 - 75