Open AccessSeasonal and diel changes in photosynthetic activity of the snow alga Chlamydomonas nivalis ( Chlorophyceae ) from Svalbard determined by pulse amplitude modulation fluorometry
Author(s) -
Stibal Marek,
Elster Josef,
Šabacká Marie,
Kaštovská Klára
Publication year - 2007
Publication title -
fems microbiology ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.377
H-Index - 155
eISSN - 1574-6941
pISSN - 0168-6496
DOI - 10.1111/j.1574-6941.2006.00264.x
Subject(s) - diel vertical migration , biology , photosynthesis , chlorophyceae , snow , botany , chlamydomonas , algae , irradiance , photosynthetically active radiation , chlorophyll fluorescence , chlorophyta , ecology , physics , optics , biochemistry , meteorology , mutant , gene
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 μS cm −1 . The temperature of snow was stable (−0.1 to +0.1°C), and the incident radiation values ranged from 11 to 1500 μmol photons m −2 s −1 . The photosynthetic activity had seasonal and diel dynamics. The F v / F m values ranged between 0.4 and 0.7, and generally declined over the course of the season. A dynamic response of F v / F m to the irradiance was recorded. According to the saturating photon fluence values E k , 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.