Blue Ligth Effect On Growth

Aquatic Botany 78 (2004) 265–277

Blue light effect on growth, light absorption
characteristics and photosynthesis of five
benthic diatom strains
Jesús M. Mercado a,∗ , M. del Pilar Sánchez-Saavedra b ,
Gabriel Correa-Reyes b , Luis Lubián c , Olimpio Montero c ,
Félix L. Figueroa d
a

Centro Oceanográfico de Málaga, Instituto Español de Oceanograf´a,
ı
Puerto Pesquero s/n. Apdo.285,E-29640, Spain
b Departamento de Acuicultura, Centro de Investigación Cient´fica y Educación Superior de Ensenada
ı
(CICESE) Apdo. Postal 2732, C.P. 22830 Ensenada, Baja California, Mexico
c Instituto de Ciencias Marinas de Andaluc´a (CSIC) E-11510 Puerto Real, Cádiz, Spain
ı
d Departamento de Ecolog´a, Facultad de Ciencias, Universidad de Málaga, E-29071 Málaga, Spain
ı
Received 19 November2002; received in revised form 16 September 2003; accepted 19 November 2003

Abstract
Bio-optical characteristics and photosynthetic performance of five strains of benthic diatoms
belonging to three different species (Nitzschia thermalis Kützing var. minor Hilse sensu Podzorski,
Nitzschia laevis Hust and Navicula incerta Grunow) were examined. The effects of treatments with
monochromatic bluelight (BL) were also determined. The values of photosynthesis rate at saturating photon fluence rate (PFR) (Pmax ) and ascending initial slope of the P-PFR curves ( ) ranged
from 0.22 to 3.58 mol O2 per mg Chl a min−1 and from 0.012 to 0.169 mol O2 per mg Chl a
( mol photons m−2 s−1 )−1 respectively. Onset of light saturation parameter (Ek ) ranged from 43
to 12 mol photons m−2 s−1 . Thesevalues were comparable to those reported from measurements
performed with sub-tidal benthic communities. In vivo effective optical cross-section of Chl a (a∗
values) was correlated to average cell surface area. Interestingly, a∗ and α were also negatively correlated, probably indicating that a higher pigment packaging affects negatively to α. The acclimation
of the five strains to monochromatic BLfor 2 weeks produced a reduction of Pmax and α although
the effective quantum yield of photosystem II ( F/Fm ) was not affected. In addition to these
changes, chlorophyll a increased and a∗ decreased in the five strains. Therefore, it was concluded

∗ Corresponding author. Tel.: +34-952476955; fax: +34-952463808.
E-mail address: jesus.mercado@ma.ieo.es (J.M. Mercado).

0304-3770/$ – see frontmatter © 2004 Elsevier B.V. All rights reserved.
doi:10.1016/j.aquabot.2003.11.004

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J.M. Mercado et al. / Aquatic Botany 78 (2004) 265–277

that the reduction of a∗ could contribute to the changes in the photosynthetic performance in BL.
© 2004 Elsevier B.V. All rights reserved.
Keywords: Bio-optic; Benthic diatoms; Chlorophyll fluorescence; Light quality; Photosynthesis

1.Introduction
Benthic diatoms are cultured usually under controlled conditions in order to be used
as food for other organisms such as abalone and sea urchin (Dunstan et al., 1994) or for
biotechnological applications (Stoermer and Smol, 1991). In spite of their potential uses,
only a few reports describe the effects of culture condition changes in the benthic diatom
strain growth (Tadros andJohansen, 1988). Recently, several species potentially usable
for culturing abalone have been isolated and the effect of different treatments have begun
to be studied (Correa-Reyes et al., 2001; Simental-Trinidad et al., 2001). Overall, among
the factors which control the production of microalgae valuable in aquaculture, several
studies have tested the effect of changes on spectral composition oflight. In particular,
some works have investigated the effects of the monochromatic blue light on the growth
in a number of phytoplankton species (Flaak and Epifanio, 1978; Sánchez-Saavedra and
Voltolina, 1994, 1995). According to these reports, this manipulation of the light field
produces changes on growth rates and pigment contents which affect the nutritional value
of the microalgae....