Seasonal and diel changes in photosynthetic activity of the snow alga Chlamydomonas nivalis (Chlorophyceae) from Svalbard determined by pulse amplitude modulation fluorometry
Language English Country Great Britain, England Media print
Document type Journal Article, Research Support, Non-U.S. Gov't
PubMed
17313577
DOI
10.1111/j.1574-6941.2006.00264.x
PII: FEM264
Knihovny.cz E-resources
- MeSH
- Chlamydomonas isolation & purification physiology MeSH
- Fluorometry methods MeSH
- Photosynthesis physiology MeSH
- Seasons * MeSH
- Snow chemistry microbiology MeSH
- Light MeSH
- Darkness MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Geographicals
- Arctic Regions MeSH
The seasonal and diel dynamics of the physiological state and photosynthetic activity of the snow alga Chlamydomonas nivalis were investigated in a snowfield in Svalbard. The snow surface represents an environment with very high irradiation intensities along with stable low temperatures close to freezing point. Photosynthetic activity was measured using pulse amplitude modulation fluorometry. Three types of cell (green biflagellate vegetative cells, orange spores clustered by means of mucilaginous sheaths, and purple spores with thick cell walls) were found, all of them photosynthetically active. The pH of snow ranged between 5.0 and 7.5, and the conductivity ranged between 5 and 75 microS cm(-1). The temperature of snow was stable (-0.1 to +0.1 degrees C), and the incident radiation values ranged from 11 to 1500 micromol photons m(-2) s(-1). The photosynthetic activity had seasonal and diel dynamics. The Fv/Fm values ranged between 0.4 and 0.7, and generally declined over the course of the season. A dynamic response of Fv/Fm to the irradiance was recorded. According to the saturating photon fluence values Ek, the algae may have obtained saturating light as deep as 3 cm in the snow when there were higher-light conditions, whereas they were undersaturated at prevalent low light even if on the surface.
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