ISSN 1063-0740, Russian Journal of Marine Biology, 2006, Vol. 32, No. 1, pp. 20–27. © Pleiades Publishing, Inc., 2006.
Original Russian Text © G.M. Voskoboinikov, M.V. Makarov, I.V. Ryzhik, 2006, published in Biologiya Morya.
The adaptations of the algal photosynthetic appara-
tus to reduced irradiance have been studied in various
systematic groups of macrophytes. Increased contents
of photosynthetic pigments in macrophytes in response
to reduced light levels have been found in nature and in
experiments [9, 11, 15, 18, 19, 25].
There are contradictory reports on the effect of full
darkness on the photosynthetic apparatus and viability
of algae. In some algae, in the absence of light, the pho-
tosynthetic apparatus was destroyed  or the photo-
synthetic rates were reduced . On the other hand,
the accumulation of pigment was observed in algae
after 3 months in full darkness [17, 22].
This study examines alterations occurring in algae
at high latitudes in darkness.
MATERIALS AND METHODS
Thalli of the brown algae
L. collected in the Barents Sea in summer
were placed in containers and then in the sea at a 1 m
depth. The container is a wire carcass covered with fab-
ric. Experiments were carried out in containers of black
fabric, which absorbs over 95% of transmitted light,
and white fabric, which transmits 65% of light. The
amount, composition, and ratio of photosynthetic pig-
ments, as well as the structure of tissues and cells of
algae in the containers, were compared with those of
wild plants collected in summer and in winter (polar
night). The duration of the experiments was 15 and
The qualitative and quantitative composition of pig-
ments was studied according to modiﬁed techniques [4,
5, 7]. The contents of
-carotene, violaxanthin, fucox-
anthin, and chlorophylls
were determined. The
concentrations of pigments were calculated per gram of
thallus wet weight. The dry matter content was calcu-
lated in percent of wet weight according to the gener-
ally accepted technique.
The tissue and cell morphology was examined using
standard and modiﬁed techniques [1, 13]. Morphome-
try of the electron microscopic photographs (analysis
of chloroplasts, mitochondria, and physodes) was made
according to the method of Stefanov .
In the natural environment, in summer, the total
amount of photosynthetic pigments (chlorophylls and
Changes in the Composition of Photosynthetic Pigments
and Cellular Structure of the Brown Algae
L. from the Barents Sea during a Prolonged
Period of Darkness
G. M. Voskoboinikov, M. V. Makarov, and I. V. Ryzhik
Murmansk Marine Biological Institute, Kola Scientiﬁc Center, Russian Academy of Sciences, Murmansk, 183038 Russia
Received June 10, 2005
—The effect of a prolonged absence of light on the photosynthetic pigment content and cell ultrastruc-
L. from the Barents Sea was investigated during a 30-day experi-
ment in summer and under natural conditions in winter (at the end of the polar night). With decreasing irradi-
ance, the accumulation of photosynthetic pigments, mainly violaxanthin, occurred. In the absence of light, the
contents and ratio of pigments remained unchanged. At the end of the experiment, the following changes
occurred in the cellular ultrastructure: the disappearance of the stored substances and the change in the shape
and compression of the physodes. Higher proportions of mitochondria in the cell and of cristae in the mitochon-
dria are indicative of the enhancement of the respiration processes. No degradational changes were found in the
tissues and cells of fucoids during prolonged periods of darkness. This suggests the possibility of their transition
from photoautotrophy to endogenous nutrition.
Fucoids, polar night, darkness, cellular structure, physodes, photosynthetic pigments, endogenous