International Journal of Marine Science 2016, Vol.6, No.01, 1-8
1
ResearchArticle Open Access
Biological Responses of the Marine Diatom
Chaetoceros simplex
Ostenfeld
to Different Treatments of Phosphate andNitrate
Nassar M.Z.
1,
, Hamdy R. M., Galal.
2
, Khairy H.M.
1
, Rashedy S.H.
1
1. National Institute of Oceanography and Fisheries, Hydrobiology Lab, Egypt.
2. Botany Department, Faculty of Science, South Valley University, Egypt
Corresponding author email
International Journal of Marine Science, 2016, Vol.6, No.01 doi: 10.5376/ijms.2016.06.0001
Received: 28 Sep., 2015
Accepted: 09 Nov., 2015
Published: 01 Jan., 2016
Copyright
©
2016 Nassar et al., This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted
use, distribution, and reproduction in any medium, provided the original work is properly cited.
Preferred citation for this article:
Nassar M. Z., Galal H. R. M., Khairy H. M., and Rashedy S. H., 2016, Biological Responses of the Marine Diatom
Chaetoceros simplex
Ostenfeld to Different
Treatments of Phosphate and Nitrate, International Journal of Marine Science, Vol.6, No.01 1
-
8
)
Abstract
Chaetoceros simplex
Ostenfeld of marine diatoms was isolated and purified from the sub-surface waters of the
north-western part of the Red Sea, Egypt
(Hurgada). The isolated grown cells are exposed to different concentrations of nitrate and
phosphate to estimate their effects on the growth and some metabolic activities of the organism. In general, the results indicated that
concentrations of 100 μM nitrate and 5μM phosphate stimulated the algal growth by 60% and 32 %, respectively in the 8
th
day of
culture. While, the values of 300 μM nitrate and 50 μM phosphate exhibited a decrease in the algal growth by 44 % and 49 %,
respectively as compared with the control culture. The photosynthetic pigments (Chl-a, Chl-c and Carotenoids), total soluble proteins
and carbohydrates of
Chaetoceros simplex
followed a similar pattern of change to that of growth in response to different treatments
of nitrate and phosphate. While, the addition of different treatments of nitrate and phosphate to F/2 medium decreased the total lipids
of
C. simplex.
Statistical analysis of the data indicated that 5 μM phosphates and 50 μM nitrates were the highly significant and
most effective concentrations that positively affect most of different metabolic activities of
Chaetoceros simplex
. Thus,
Chaetoceros
simplex
culture could be used as larval feed or other purposes cultured using 50 μM nitrate and 5μM phosphate
.
Keywords
Chaetoceros simplex
; Nitrate; Phosphate;Metabolic activities
Introduction
The phys iology of microalgae is affec ted b y
physicochemical factors such as water temperature,
salinity, light intensity, nutrient concentrations, and
pH. It, however, is hard to identify the influence of
environmental factors on the microalgae directly in
nature. Thus , the phys iolo gic a l exper iments
are generally applied to understand the mechanism of
environmental impacts on the different metabolic
activities of microalgae through the laboratory culture
studies (Cho et al., 1998).
Concentrations of cells in phytoplankton cultures are
generally higher than those found in nature. Microalgae
cultures must therefore be enrichedwith nutrients to make
up for the deficiencies in the seawater. Macronutrients
include nitrate, phosphate (in an approximate ratio of 6:1),
and silicate. Silicate is specifically used for the growth of
diatoms that utilize this compound for production of an
external shell. Micronutrients cons ist of various
trac e metals and the vitamins like, thiam ine
(B1), cyanocobalamin (B12) and sometimes biotin.
Two enric hment media that have been us ed
extens ively and are suitable for the growth of
most marine microalgae are Walne medium and
Guillard’s F/2 medium. Generally, the most common
nutrient medium used is F/2 standard described by
Guillard and Ryther (1993). The complexity and cost
of the above culture media often excludes their use for
large scale culture operations. Alternative enrichment
media that are suitable for mass produc tion of
microalgae in large-scale extensive systems contain
only the most essential nutrients and are composed of
agric ulture grade rather than laboratory grad e
fertiliz ers (La ve ns and Sorg e loos , 1996).
Krichnavaruka et al. (2005) studied the optimal
growth conditions and the cultivation of
Chaetoceros
calcitrans
in airlift photobioreactor, and they found
that a modified of standard F/2 medium with a two
folds of silica and phosphorus concentrations was
illustrated to result in a better growth of this diatom.
Vitamin B12 in the range from 1 to 3 μg·l
−1
did not
significantly affect the growth.
