TY  - JOUR
A1  - Spijkerman, Elly
A1  - Wacker, Alexander
T1  - Interactions between P-limitation and different C conditions on the fatty acid composition of an extremophile microalga
JF  - Extremophiles : life under extreme conditions
N2  - The extremophilic microalga Chlamydomonas acidophila inhabits very acidic waters (pH 2-3.5), where its growth is often limited by phosphorus (P) or colimited by P and inorganic carbon (CO(2)). Because this alga is a major food source for predators in acidic habitats, we studied its fatty acid content, which reflects their quality as food, grown under a combination of P-limited and different carbon conditions (either mixotrophically with light + glucose or at high or low CO(2), both without glucose). The fatty acid composition largely depended on the cellular P content: stringent P-limited cells had a higher total fatty acid concentration and had a lower percentage of polyunsaturated fatty acids. An additional limitation for CO(2) inhibited this decrease, especially reflected in enhanced concentrations of 18:3(9,12,15) and 16:4(3,7,10,13), resulting in cells relatively rich in polyunsaturated fatty acids under colimiting growth conditions. The percentage of polyunsaturated to total fatty acid content was positively related with maximum photosynthesis under all conditions applied. The two factors, P and CO(2), thus interact in their effect on the fatty acid composition in C. acidophila, and colimited cells P-limited algae can be considered a superior food source for herbivores because of the high total fatty acid content and relative richness in polyunsaturated fatty acids.
KW  - Acidophilic algae
KW  - Cellular P quota
KW  - Chlamydomonas acidophila
KW  - Chlorophyceae
KW  - Colimitation
KW  - CO(2)
KW  - Fatty acid composition
KW  - Food quality
KW  - Glucose
KW  - Mixotrophy
KW  - Photosynthesis
KW  - Phytoplankton
KW  - Phosphorus limitation
Y1  - 2011
U6  - https://doi.org/10.1007/s00792-011-0390-3
SN  - 1431-0651
VL  - 15
IS  - 5
SP  - 597
EP  - 609
PB  - Springer
CY  - Tokyo
ER  - 
TY  - JOUR
A1  - Spijkerman, Elly
A1  - Lukas, Marcus
A1  - Wacker, Alexander
T1  - Ecophysiological strategies for growth under varying light and organic carbon supply in two species of green microalgae differing in their motility
JF  - Phytochemistry : an international journal of plant biochemistry
N2  - Mixing events in stratified lakes result in microalgae being exposed to varying conditions in light and organic carbon concentrations. Stratified lakes consist of an upper illuminated strata and a lower, darker strata where organic carbon accumulates. Therefore, in this contribution we explore the importance of dissolved organic carbon for growth under various light intensities by measuring some ecophysiological adaptations in two green microalgae. We compared the non-motile Chlorella vulgaris with the flagellated Chlamydomonas acidophila under auto-, mixo-, and heterotrophic growth conditions. In both algae the maximum photosynthetic and growth rates were highest under mixotrophy, and both algae appeared inhibited in their phosphorus acquisition under heterotrophy. Heterotrophic conditions provoked the largest differences as C. vulgaris produced chlorophyll a in darkness and grew as well as in autotrophic conditions, whereas Chl. acidophila bleached and could not grow heterotrophically. Although the fatty acid composition of both phytoplankton species differed, both species reacted in a similar way to changes in their growth conditions, mainly by a decrease of C18:3n-3 and an increase of C18:1n-9 from auto- to heterotrophic conditions. The two contrasting responses within the group of green microalgae suggest that dissolved organic carbon has a high deterministic potential to explain the survival and behaviour of green algae in the deeper strata of lakes.
KW  - Chlamydomonas acidophila
KW  - Chlorella vulgaris
KW  - Chlorophyceae
KW  - Ecophysiology on freshwater phytoplankton
KW  - Glucose
KW  - Mixotrophy
KW  - Osmotrophy
KW  - Heterotrophy
KW  - Photosynthesis
KW  - Fatty acids
Y1  - 2017
U6  - https://doi.org/10.1016/j.phytochem.2017.08.018
SN  - 0031-9422
SN  - 1873-3700
VL  - 144
SP  - 43
EP  - 51
PB  - Elsevier
CY  - Oxford
ER  -