Open AccessEcological consequences of photomovement and photobleaching in the marine flagellate Cryptomonas maculata
Author(s) -
Häder DonatP.,
Rhiel Erhard,
Wehrmeyer Werner
Publication year - 1988
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1988.tb02642.x
Subject(s) - phototaxis , flagellate , photobleaching , biology , photosynthesis , botany , ecology , fluorescence , physics , quantum mechanics
The marine flagellate Cryptomonas maculata is bleached and eventually killed by exposure to even moderate white‐light fluence rates. Bleaching affects all of its photosynthetic pigments and the kinetics depend on the fluence rate of the radiation the organisms are exposed to. Nitrogen‐deficient cells which show a reduced pigment concentration and impaired photosynthetic efficiency tolerate bleaching white‐light exposure far better than the normally colored cells. In their natural environment the organisms escape this situation by a pronounced negative phototaxis at fluence rates above 3.6 klx (= 15 W.m −2 ), while they show positive phototaxis at lower fluence rates. In nitrogen‐deficient cells, however, though being less prone to photobleaching, negative phototaxis commences even at a fluence rate of about 830 lx (= 3.5 W.m −2 ). The ecological consequences of the remarkable light sensitivity and the phototactic orientation are being discussed.