Motility and photosynthetic responses of the green microalga Tetraselmis subcordiformis to visible and UV light levels.

MA, Z.; HELBLING, E.W; LI, W.; VILLAFAÑE, V. E.; GAO, K

JOURNAL OF APPLIED PHYCOLOGY

SPRINGER

Lugar: Berlin; Año: 2012 vol. 6 p. 1613 - 1621

0921-8971

To test the effects of photosynthetic active radiation (PAR, 400–700 nm) and ultraviolet radiation (UVR, 280–400 nm) on phototaxis and photosynthesis of free swimming microalgae, experiments were performed withTetraselmis subcordiformis (Wille) Butcher under a solar simulator. In particular, we evaluated the effects of different PAR levels and radiation regimes (i.e., PAR only and PAR+UVR) on those two processes.We found that the cells preferred tomove to a particular area (e.g., receiving 100 Wm−2 PAR) with little photochemical suppression or inhibition of carbon fixation. Adding UV-A to high PAR decreased its swimming capacity and photosynthetic capability, and further adding UV-B led to more inhibition. The suppression of the moving capability of T. subcordiformiswas reversible but the cells exposed to PAR combined with UVR needed longer time intervals to recover their motility as compared with those irradiated only with PAR. Based on the above results, we postulate that in nature, the motile capability and photosynthesis of free swimming the green microalga might be impaired by enhanced solar UVR. On the other hand, the cells can reduce the damage caused by high irradiances (and even get the optimum light level for photosynthesis) by a behavioral swimming response.