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CHAPTER 2
LITERATURE REVIEWS
2.1 Introduction to Cladophora
Genus Cladophora Kützing is a branching, filamentous green alga
(Chlorophyta, Cladophorales, Cladophoraceae) in both marine and freshwater
ecosystems. It grows in various habitats and environments. Generally, Cladophora is
an attached alga but may also form free-floating or loose mats on soft substrates
(Prescott, 1975; Dodds and Gudder, 1992; Smith, 1950; Bootsma and Jensen, 2007)
(Figure 1-2).
Figure 1. Cladophora A. The alga attaches on rocks in Nan River B. A
photograph of whole plant
Morphologically, it is characterized by its multinucleate cells, reticulate
chloroplasts, thick cell wall and filamentous-branched thalli. Branching of freshwater
Cladophora consists of uniseriate filaments inserted at oblique to horizontal angles,
and may be sparsely to profusely spaced. Development of this alga is dominated
A B
5 cm 0.5 cm
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either by apical growth with acropetal organization or intercalary growth with an
irregular organization (Smith, 1950; Dodds and Gudder, 1992; Bootsma and Jensen,
2007; Sze, 1998; Wehr and Sheath, 2003).
Figure 2. Photomicrographs of Cladophora sp.
2.1.1 Taxonomy of freshwater Cladophora
Taxonomic identification within the genus Cladophora is difficult because this
genus exhibits high morphological variation under different ecological conditions
(van den Hoek, 1963; Whitton, 1967; Usher and Blinn, 1990; Dodds and Gudder,
1992; Bergey et al., 1995; Wilson et al., 1999; Ross, 2006). van den Hoek (1963)
established 11 sections, 38 species of the genus Cladophora based primarily on their
morphology; 11 freshwater and 27 marine. Freshwater species are found in six
sections:
Aegagropila
Cladophora aegagropila (L.) Rabenh.
Glomeratae
C. fracta var. fracta (Mull. Ex. Vahl) Kutz.
C. fracta var. intricata (Mull. Ex. Vahl) Kutz.
100 m
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C. glomerata var. glomerata (L.) Kutz.
C. glomerata var. crassior (L.) Kutz.
Cladophora
C. rivularis (L.) v.d. Hoek
C. surera Brand
Cornuta
C. cornuta Brand
Affines
C. kosterae Hoffm. Tild.
Basicladia
C. basiramosa Schmidle
C. pachyderma (Kjellm.) Brand
In Thailand, two species of freshwater Cladophora have been reported in Nan
river: C. glomerata and Cladophora sp. (Peerapornpisal et al., 2006; Peerapornpisal,
2007). In addition, Chaisuk and Waiyaka (2001) reported C. glomerata from Mekong
river, Chiang Rai.
2.2 Carotenoids
Carotenoids are organic pigments that occur naturally in plants including
algae, some fungi and bacteria. They are divided into two classes, carotenes (contain
no oxygen such as β-carotene, -carotene and lycopene; molecular formula C40H56)
and xanthophylls (contain oxygen such as lutein and zeaxanthin; molecular formula
C40H56O2). In algae, carotenoid normally exist in the chloroplasts, however they can
be in the cell wall and distribute within the chloroplast. Carotenoids assist in taking
up light energy, function as photoprotectants and antioxidants, serve as precursors for
biosynthesis of plant growth regulator, abscisic acid and protect the photosynthetic
apparatus (Goodwin, 1980; Naik et al., 2003; Wikipedia, 2007).
Carotenoids in green algae and plants are produced in two different
compartments and by two different pathways i.e. the acetate-mevalonate pathway and
the phosphoglycerraldehyde-pyruvate pathway. In all organisms, carotenoids are
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further synthesized from isopentenyl diphosphate and its isomers (Cunningham, 2002;
Goodwin, 1980; Ladygin, 2000).
Carotenoids are powerful antioxidants. Some carotenoids that are beneficial
to human health include beta-carotene (a precursor to vitamin A as well as a cancer-
preventing antioxidant), lutein and zeaxanthin (naturally present in the macula of the
human retina and which protects it by filtering phototoxic blue light and near-
ultraviolet radiation) (Burtin, 2003; Maryland Medical Center, 2006; George Mateljan
Foundation, 2006 ). Previous studies have suggested that carotenoids can prevent or
delay cancer and degenerative diseases in human and animals by contributing to
antioxidative defenses against metabolic oxidative byproduct (Omenn et al., 1996;
Tapiero et al., 2004).
2.2.1 Carotenoids in Cladophora and other algal species
Reports of carotenoids and carotenoid composition in Cladophora are few.
Powtongsook (2000) reported 340 µg g-1 of total carotenoid in Cladophora collected
from the Nan River. Whereas, Traichaiyaporn et al. (2007a) reported 840 µg g-1 of
carotenoid in Cladophora culture in 60-100% of canteen wastewater. Yoshii et al.
(2004) reported that carotenoid composition of Cladophora albida, C. coelothrix, C.
glomerata, C. japonica, C. ohkuboana, C. pellucida, C. sericea and C. vagabunda
were as follows: 22, 14, 13, 12, 12, 11, 14 and 16 µg g-1 dry weight (dw) of β-
carotene; 22, 4, 36, 2, 7, 3, 37 and 29 µg g-1 (dw) of lutein, respectively. Dere et al.
(1998) investigated carotene content in C. glomerata by extraction with three solvents
(methanol, diethyl ether and acetone) obtaining 18.8, 19.2 and 20.1 g g-1 fresh
weight, respectively.
Khuantrairong et al. (2009a) studied the effect of phosphorus on pigments
production of Cladophora sp. in mass culture with addition of di-potassium hydrogen
orthophosphate (K2HPO4) at 0-5 mg L-1. The pigments (in g g-1) were observed as
follows: chlorophyll a 148.34–347.97, chlorophyll b 55.58–249.42, total carotenoid
823.23-1,063.16, carotene 44.30–86.36, xanthophyll 778.93–997.29, -carotene
20.01-61.03, lutein 172.80-296.70 and zeaxanthin 24.62-72.17.
In other species, such as blue-green alga Spirulina, Shimamatsu (2004)
reported 4,770 µg g-1 of carotenoid of dried Spirulina powder of Siam Algae
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Company. Whereas, Chainapong and Traichaiyaporn (2009) reported 5,750–6,620 µg
g-1 of carotenoid of S. platensis cultivated under mixotrophic condition. Promya et al.
(2008) reported that -carotene content of S. platensis cultured in 100% kitchen
wastewater and 10% oil-extracted fermented soybean water were 290 and 370 µg g-1,
respectively.
Granodo-Lorencio et al. (2009) stated that zeaxanthin of a green alga
Scenedesmus almeriensis was 340 µg g-1. Whereas, Norziah and Ching (2000)
reported -carotene content of 52 µg g-1 in edible seaweed Gracilaria changgi.
2.2.2 Factors related to carotenoids production in algae
Previous studies showed that phosphorus was effective in carotenoid
production in algae. Brinda et al. (2004) reported that phosphate limitation enhanced
astaxanthin in a green alga Haematococcus pluvialis. In addition, Forján et al. (2007)
suggested that phosphate and sulfur limitation enhanced the production of β-carotene,
zeaxanthin and violaxanthin, whereas nitrogen limitation decreased those carotenoids
in marine microalga Nannochloropsis gaditana. In contrast, Khuantrairong et al.
(2009) suggested that phosphorus supply increased total carotenoid, xanthophylls,
carotene, β-carotene, lutein, zeaxanthin, chlorophyll a and chlorophyll b of
Cladophora sp. Leonardos and Geider (2005) stated that phosphorus and nitrogen
ratio was related to carotenoid and chlorophyll a production in cryptophyte
Rhinomonas reticulata. Latasa and Berdalet (1993) suggested that synthesis of
pigments in dinoflagellate Heterocapsa sp. stopped under phosphorus limitation.
Celekli et al. (2009) reported that phosphate effected biomass and carotenoid
production of Spirulina platensis and the best phosphate concentration was 0.50 g L-1.
Lin (1977) reported that hydrolysis of polyphosphates (reactants in carotenoid
pathway) by C. glomerata in the Milmaukee River was related to pH and dissolved
phosphorus in water.
Orosa et al. (2005) cultured a green microalga Haematococcus pluvialis in
different NaNO3 concentrations and found that nitrate decreased astaxanthin but
increased β-carotene, the optimum concentration of NaNO3 was 0.15 g L-1.
Cifuentes et al. (2003) cultured Haematococcus pluvialis at varying light
intensity, nitrate and acetate, suggesting that these factors affected carotenoid
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production of this species and light intensity was the best inductive carotenogenic
factor.
2.3 Nutritional values of algae
Algae are one of the significant sources of human food and they are high in
nutritional values that are beneficial for supplemental use as human food source and
animal feed. In Thailand, edible freshwater alga Cladophora is well known for
consumption in the Northern part and it is cultured for fish supplemental feed,
especially Mekong Giant Catfish (Traichaiyaporn et al., 2007b). A summary of the
nutritional values of Cladophora has been reported (in percent dw) to compose of
protein 28, fat 6.81, neutral detergent fiber 19.29, acid detergent fiber 19.06, ash
20.80, moisture 13.19, phosphorus 0.36 and carbohydrate 30.34; vitamins (in µg 100g-1
dw): vitamin B1 169.50, vitamin B2 541.10 and vitamin E 4.20; minerals (in mg 100g-1
dw): calcium 943.90, sodium 716.90, magnesium 170.5, manganese 5.36, iron 162.0,
copper 310.00 and zinc 0.65 (Ruangrit et al., 2005; Peerapornpisal, 2007).
Zbikowski et al. (2007) reported mineral content of Cladophora sp. (in mg g-1
dw) collected from Southern Baltic, Gulf of Gdansk and Vistula Lagoon, Poland were
as follows: calcium 4.5, 3.9 and 5.4; magnesium 19.4, 15.0 and 14.9; sodium 37.3,
20.9 and 17.1; potassium 53.4, 38.5 and 30.7; zinc 67.5, 63.0 and 73.1, respectively.
Whereas, Whitton (1970) reported mineral content (in percent) of C. glomerata as
sodium 0.93, potassium 3.0, magnesium 0.43, calcium 0.77 and phosphorus 0.70.
However, Keeney et al. (1976) reported that zinc values in C. glomerata collected
from Deadman Bay and Main Duck, Canada were 23.7 and 8.2 g g-1 dw,
respectively. Elenkov et al. (1996) reported that lipid content of C. vagubunda in
Lake Pomorie, Bulgaria was 1.70-3.17 mg g-1 dw.
Nutritional values of edible freshwater algae in Thailand, Spirogyra spp. (Tao)
(in g 100g-1 dw) were also reported i.e. protein 18.65, fat 5.21, carbohydrate 56.31,
fiber 7.66, ash 11.78 and moisture 8.05. Vitamin and mineral contents (in mg 100g-1
dw) were provitamin A 0.25, vitamin B1 0.04, vitamin B2 0.55, vitamin B6 0.84,
niacin 3.65, iron 33.85, manganese 35.80, magnesium 241.10, potassium 1.19, sodium
1.56, calcium 26.88 and phosphorus 125.76 (Peerapornpisal, 1992)
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Nutritional values (in g 100g-1 dw) of blue-green alga Spirulina were reported
as follows: protein 61.40, fat 8.50, moisture 3.00, fiber 3.00 and ash 7.70; vitamins
(in mg 100g-1): provitamin A 214.00, vitamin B1 1.98, vitamin B2 3.63, vitamin B6
0.59, vitamin B12 0.11 and vitamin E 11.80; minerals (in mg 100g-1 dw): phosphorus
914.00, iron 57.40, calcium 171.00, potassium 1,770, sodium 1,050 and magnesium
257.00 (Shimamatsu, 2004).
Norziah and Ching (2000) reported nutritional contents (in percent dw) of
edible seaweed Gracilaria changgi as follows: protein 6.9, lipid 3.3, fiber 24.7 and
ash 22.7; vitamin and minerals (in mg 100g-1): vitamin C 28.5, calcium 651, iron
95.6, zinc 13.8, copper 0.8 and cadmium 0.3. Whereas, McDermid and Stuercke
(2003) revealed vitamin C content of 3 mg g-1 in Hawaiian seaweeds Enteromorpha
flexuosa.
Gressler et al. (2010) reported nutritional values (in percent dw) of four
species of seaweeds Laurencia filiformis, L. intricate, Gracilaria domingensis and G.
birdiae as follows: soluble protein 6.2, 7.1, 18.3 and 4.6; total lipid 1.3, 1.3, 6.2 and
1.1; and ash 23.8, 22.5, 38.4 and 33.5, respectively. Whereas, nutritional values of
edible seaweed Palmaria palmate and Enteromorpha spp. were reported as follows:
9.7-25.5% of protein in Palmaria palmata; 9-14% of protein and 32-36% of ash in
Enteromorpha spp. (Galland-Irmouli et al., 1999; Aguilera-Morales et al., 2005).
Ash (in g 100g-1 dw) and mineral contents (in mg g-1 dw) were reported from five
edible marine seaweeds of Spain as follows: Fucus vesiculosus, ash 30.10, Na 54.69,
K 43.22, Ca 9.38, Mg 9.94, Fe 0.04, Zn 0.04 and Mn 0.06; Laminaria digitata
(Kombu), ash 37.59, Na 38.18, K 115.79, Ca 10.05, Mg 6.59, Fe 0.03, Zn 0.02 and
Mn <0.01; Undaria pinnatifida (Wakame), ash 39.26, Na 70.64, K 86.99, Ca 9.31,
Mg 11.81, Fe 0.08, Zn 0.02 and Mn 0.01; Chondrus crispus (Irish moss), ash 21.08,
Na 42.70, K 31.84, Ca 4.20, Mg 7.32, Fe 0.04, Zn 0.07 and Mn 0.01; Porphyra tenera
(Nori), ash 20.59, Na 36.27, K 35.00, Ca 3.90, Mg 5.65, Fe 0.10, Zn 0.02 and Mn
0.02 (Rupérez, 2002).
Nutritional values of microalgae were reported from Chaetoceros muelleri,
Chaetoceros sp., Isochrysis galbana, Isochrysis sp., Pavlova salina, Pavlova sp.,
Micromanas pusilla, Prasinophyta sp. and Chlorella vulgalis (Martínez-Fernández et
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al., 2006; Ponis et al., 2006; Cai et al., 2007; Janczyk et al. 2007). These species
showed high protein contents suitable for fish larvae feed.
The vitamin contents of five microalgae used for aquaculture in France were
reported. On a dry weight basis, Tetraselmis suecica contained 4,280 μg g−1
provitamin A and 6,323 μg g−1 vitamin E; Pavlova lutheri 1,162 μg g−1 vitamin B12
and 837 μg g−1 vitamin C; Isochrysis galbana 183 μg g−1 vitamin B6 and Skeletonema
costatum 710 μg g−1 vitamin B1 (Roeck-Holtzhauer et al., 1991).
The vitamin C content (in mg g-1 dw) were reported from seaweeds Alaria
valida 0.53, Egregia menziesii 0.04, Fucus evanescens 0.24, Hedophyllum sessile
0.21, Macrocystis pyrifera 0.19, Postelsia palmaeformis 0.09, Agarum fimbriatum
0.02, Costaria costata 0.02, Desmarestia munda 0.01, Laminaria bullata 0.02,
Enteromorpha sp. 0.15, Ulva lactuca 0.46, Gigartina papillata 0.41, Grateloupia
Cutleriae <0.01, Halosaceion glandiforme 0.13, Iridaea sp. 0.26, Porphyra naiadum
0.36, P. nereocystis 0.53, P. perforata 0.60, Prionitis lyallii 0.03, Turnerella pacifica
0.09, Agardhiella tenera <0.01, Anatheca fureata <0.01, Callophyllis sp. <0.01,
Dasyopsis plumosa <0.01, Hymenena sp. <0.01, Opuntiella californica <0.01,
Polyneura latissima <0.01 and Ehodymenia pertusa <0.01 (Norris et al., 1936).
2.4 Biomass production and biomass production rate of Cladophora
The reports on biomass production and growth rate of Cladophora are few.
Pitcairn and Hawkes (1973) reported biomass production (in g m-2 dw) of Cladophora
growth in rivers of UK were as follows: River Arrow 34.6-73.7, River Cole 5.0-50.1,
River Blythe 52.6-60.3, River Tean 20.3-31.6, River Ray 14.5-66.4, River Great Stour
5.0-74.7 and River Darent 62.9. Whereas, Parker and Maberly (2000) observed
biomass production of Cladophora in South Basin and North Basin of Windermere,
UK were 29 and 4.7 g m-2 dw, respectively. The biomass production (in g m-2 dw) of
Cladophora vagabunda were reported from Childs River, 220 and Sage Lot Pond,
USA, 37 (Peckol and Rivers, 1996). Whereas, biomass production (in g m-2 dw) of C.
glomerata were reported from the Neva Estuary, Russia, 95-508 (Gubelit, 2009) and
the Laurentian Great Lake, Canada, 175-200 (Higgins et al., 2008).
Traichaiyaporn et al. (2007a) reported the highest biomass production of
Cladophora culture in laboratory with canteen wastewater, 360 m g-2 wet weight.
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Whereas, biomass production and growth rate of Cladophora in mass culturing were
reported from Cladophora cultured in cement raceway ponds using canteen
wastewater, 253-3,187 g m-2 (wet weight) and Cladophora culture in soil raceway
ponds using fish pond water, 3,117-20,250 g m-2 (wet weight), the highest growth rate
were 1,247 and 1,747 g m-2 week-1, respectively (Traichaiyaporn et al., 2010).
Auer and Canale (1982) indicated that Cladophora growth rate was strongly
related to tissue phosphorus content which was between 1 to 2 µg mg-1, the specific
growth rate was generally between 0.10-0.25 day-1.
2.4.1 Factors related to biomass production and morphology of Cladophora
Many factors, including light intensity, water temperature, pH, water velocity,
suspended solids, and nutrient concentrations were found to influence growth, growth
rate, primary production and morphology of Cladophora (Whitton, 1967; Wong and
Clark, 1976; Birch et al., 1981; Auer, 1994; Graham et al., 1982; Hoffmann and
Graham, 1984; Painter and Kamaitis, 1987; Wilson et al., 1999; Bootsma et al., 2004;
Sandgren et al., 2005; Bootsma et al., 2006; Higgins et al., 2006a; Bootsma and
Jensen, 2007).
Cladophora requires a hard surface for attachment, a relatively high light
environment, ambient pH between 7 and 10, and some degree of water motion. It
grows in oligotrophic to eutrophic ecosystems. Excessive growth is generally
associated with eutrophic water (Whitton, 1970; Higgins et al., 2008).
Reports on nitrogen limiting Cladophora growth from freshwater ecology are
few and a majority of studies indicated phosphorus as limiting nutrient for growth
(Higgins et al., 2008). Pitcairn and Hawkes (1973), Wong and Clark (1976), Birch et
al. (1981), Wharfe et al. (1984), Painter and Kamaitis (1987), Bootsma et al. (2004)
and Higgins et al. (2006a) suggested that phosphorus is a main factor related to
growth and production of freshwater Cladophora. It can also be abundant in habitats
where nitrogen supply limits primary production (Dodds, 1991; Dodds and Gudder,
1992). In addition, Parker and Maberly (2000) stated that nitrogen is not an important
growth limiting factor for Cladophora in North and South Basin of Windermere,
Cumbria, UK, the main factor is phosphate phosphorus.
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Painter and Kamaitis (1987) reported that Cladophora growth in Lake
Ontario, Canada was limited due to low concentrations of phosphorous. The critical
phosphorus level for Cladophora in this lake appears to be below 0.01 mg L-1.
Whereas, research in Lake Michigan showed that Cladophora blooms were related to
high phosphorus levels in water, mainly as a result of human activity such as
agricultural runoff, land fertilizer, poorly maintained septic systems and inadequate
sewage treatments. While phosphorus input from rivers may support Cladophora
production near river outlets, a comparison of estimated phosphorus demand with
river phosphorus inputs suggests that most Cladophora productions is supported by
phosphorus cycling processes within Lake Michigan (Bootsma et al., 2006).
Whereas, C. glomerata bloom in the Neva Estuary, Russia was started in mid-May,
when the water temperatures reached +10 OC. The biomass productions were 95-508
g m-2 dw (Gubelit, 2009).
Higgins et al. (2006b) stated that Cladophora growth in Eastern Lake Erie was
highly sensitive to spatial and temporal variations in soluble phosphorus
concentration. Whereas, Auer (1994) observed that high dissolved phosphorus values
in water induced an increase in stored phosphorus and growth rate of Cladophora.
These were supported by Wharfe et al. (1984). They reported that high dissolved
phosphorus effected the growth rate and hence the accumulation of C. glomerata at
downstream of the River Great Stour, England.
Hagen and Braune (2000) observed that the main environmental factors
controlling C. glomerata growth in the river Ilm, Germany are light intensity, current
velocity, pH, soluble reactive phosphorus and ammonia-nitrogen.
Bellis and McLarty (1967) suggested that light and temperature are very
important ecological factors with respect to growth and periodicity of C. glomerata in
Southern Ontario, Canada. Whereas, Cheney and Hough (1983) reported that
productivity of C. fracta in Shoe Lake, Michigan correlated most strongly with total
alkalinity and pH when phosphorus and nitrogen were above the limiting
concentrations. Higgins et al. (2008) stated that C. glomerata blooms in the
Laurentian Great Lake, Canada related to ecosystem level changes in substratum
availability, water clarity and phosphorus recycling.
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Study on the cultivation of Cladophora using canteen wastewater had been
done by Traichaiyaporn et al. (2007a; 2010). They suggested that the optimal
phosphate concentrations of canteen wastewater on algal growth in laboratory cultures
were 0.11-1.88 mg L-1. Whereas, the optimal phosphate concentration of canteen
wastewater on algal growth in mass culture was 0.01-14.78 mg L-1. They concluded
that biomass production was strongly correlated to temperature, light intensity and
nutrient concentrations and this alga can improve water quality with decreased BOD,
COD and nutrients of wastewater.
Laboratory experiments by Auer and Canale (1982) indicated that Cladophora
growth rate was strongly related to tissue phosphorus content. They observed that
tissue phosphorus content was between 1 to 2 µg mg-1, the specific growth rate was
generally between 0.10-0.25 day-1. This was supported by Bootsma et al. (2006), who
suggested that tissue phosphorus content of Cladophora was positivly correlated to
growth rate and biomass. van den Hoek (1963) observed that C. glomerata
apparently requires eutrophic conditions, where the pH is rather high (7.5-8.5).
Pitcairn and Hawkes (1973) cultured Cladophora in flasks with synthetic
media containing phosphorus from 0.1 to 7 mg L-1 and found no significant increase
in growth when phosphate was above 1 mg L-1, but it was significant when phosphate
was below 1 mg L-1.
Whitton (1967) cultured C. glomerata in flasks with a modified CHU No. 10
medium at varying temperatures and light intensities and found that rapid growth
occurred between 15 and 25 °C, whilst 6 and 30 °C were the lower and upper limits of
detectable growth. The algal growth rate increased when the light intensity was up to
7,500 lux. It was found that light intensity had a marked effect on the growth form at
all temperatures tested (15-25 °C) and that higher light intensity induced a greater
degree of branching. Bellis (1968) found that cultures of C. glomerata were killed at
initial pH values less than 7.0 and above 10.0.
Robinson and Hawkes (1986) studied the growth of C. glomerata in flasks
with continuous flow culture. They revealed that optimal specific growth rate
occurred at 20 OC, light intensity 6,000 lux, photoperiod 24 h, ammonia-nitrogen 0.18-
0.20 mg L-1, nitrite-nitrogen 0.077-1.057 mg L-1, nitrate-nitrogen 7.2-15.2 mg L-1 and
phosphate-phosphorus 0-1.9 mg L-1.
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Hoffmann and Graham (1984) revealed that temperature was the first factor
affecting dry weight production of Cladophora in laboratory culture. The maximum
dry weight production occurred at 25 OC. The second and third factors were light
intensity and photoperiod, the highest dry weight was observed at light intensity 125
mol m-2 s-1 and photoperiods 16 h. In addition, the photoperiod is the primary factor
influencing zoosporogenesis, 8 h light:16 h dark photoperiods elicited the greatest
number of zoosporangia.
Laboratory experiments of Cladophora showed that photosynthetic production
of dissolved oxygen decreased significantly below 25 °C, the maximum
photosynthetic rate was observed at 25 °C to 31 °C (Graham et al., 1982).
Cladophora grown in nutrient-depleted media do not produce any branches,
but generate long cells (Wilson et al., 1999). In natural environments, exposure to
strong sunlight can decrease the diameter of Cladophora cells (Bellis and McLarty,
1967). Rönnberg and Lax (1980) reported reduced cell lengths in filaments of
Cladophora exposed to high wave action in the littoral region of the north Baltic. van
den Hoek (1963) showed a trend for increased branching of Cladophora with
increased water velocity.
Data from Wilson et al. (1999), Usher and Blinn (1990) and Salovius and
Bonsdorff (2004) indicated that high suspended sediment decreased biomass and cell
length of C. glomerata, but increased cell width. Bergey et al. (1995) reported a
reduction of branch number and fragmentation of C. glomerata in high water
velocities. Shyam (1980) observed that the morphology of C. callicoma in natural
and cultural conditions were similar. Whereas, Khuantrairong and Traichaiyaporn
(2008) stated that addition of phosphorus in standard media decreased cell width and
cell length of Cladophora sp. under standing water cultures.
Cladophora is usually absent in fast flowing water. It is abundant in water
with appropriate flow rate of 20 cm s-1 (Pitcairn and Hawkes, 1973). Zimmermann
(1961) studied the effect of flow rate and concentration of sewage on various algal
growth, found that growth of C. glomerata in the presence of the highest sewage
concentration tested occurred at flow rates of 20 cm s-1 and 80 cm s-1.
Furthermore, Menendez et al. (2002) cultured a green macroalga
Chaematomorpha linum in different phosphorus and nitrogen concentration and found
15
that these nutrients affected biomass production, the highest biomass was observed
when both phosphorus and nitrogen were added.
2.5 Molecular study of Cladophora
Identification of Cladophora is difficult because of its morphological
variations in different ecosystems (van den Hoek, 1963; Whitton, 1967; Usher and
Blinn, 1990; Dodds and Gudder, 1992; Bergey et al., 1995; Wilson et al., 1999; Ross,
2006). Therefore molecular studies were performed for taxonomic and phylogenetic
studies within the genus Cladophora and often amplified in the ribosomal internal
transcribed spacer (ITS) region (Ponsen and Looijen, 1995). ITS refers to a piece of
non-functional RNA situated between structural ribosomal RNA (rRNA) on a
common precursor transcript. This polycistronic rRNA precursor transcript contains
the 5’ external transcribed sequence (5’ETS), 18S rRNA, ITS1, 5.8S rRNA, ITS2,
28S rRNA and 3’ETS (Wikipedia, 2008).
Studies on nucleotide sequences of rRNA ITS region in Cladophora albida by
Bakker et al. (1992) indicated that the ITS sequences of C. albida within Atlantic and
Pacific regions had similarity of 99% and 99.5%, respectively, whereas between these
regions similarity sequence was 79%. Moreover, Bakker et al. (1995a) studied the
phylogeographic relationships of C. vagabunda from the Atlantic and Pacific oceans
based on these nucleotide sequences. They suggested that C. vagabunda was closely
related to C. albida and this species from Pacific region is a monophyletic group.
Bakker et al. (1994) explored some of the diversity within the generic
complex Cladophora and its siphonocladalean allies using 18S rRNA gene sequences
and confirmed that there is no basis for the independent recognition of the
Cladophorales polyphyletic. Studies of nuclear rRNA ITS sequences in the 13
species of Cladophora albida/sericea clade showed six ITS sequence types, four of
which exhibited virtually no within-type sequence divergence (Bakker et al., 1995b)
Ross (2006) amplified the ITS region of freshwater Cladophora from North
America, including cultures of C. glomerata var. glomerata, C. glomerata var.
crassior and C. fracta var. fracta from Europe. The results indicated that the
sequences of these species had high similarity (98%). Whereas, Marks and
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Cummings (1996) reported the DNA sequences variation in the ITS region of C.
glomerata, C. albida, C. columbiana and C. vagabunda.
Bot et al. (1991) analyzed the reassociation kinetics of the DNA from C.
pellucid and indicated that the genome of this alga comprised of approximately 75%
repetitive sequences and no significant divergence was observed between the single-
copy sequences of this species isolated from the East Atlantic coast and
Mediterranean Sea. Whereas, Báez et al. (2005) suggested that Cladophora in the
western Mediterranean Sea and the Adriatic Sea were significantly similar in
distribution patterns (Chorotypes).
Hanyuda et al. (2002) performed molecular phylogenetic analyses using
nuclear 18S rRNA gene sequences to reveal the relationship between Aegagropila
linnaei and Cladophora sp. They stated that A. linnaei from two localities (Lake
Akan and Lake Dannemora) showed identical nucleotide sequences and there was
0.9% divergence between A. linnaei and Cladophora sp.
Leliaert et al. (2007) studied the molecular phylogeny of the Siphonocladales,
Clodophorophyceae based on partial large subunit (LSU) and small subunit (SSU)
rRNA of 166 samples. The results revealed that nine siphonocladalean clades were
observed and all siphonocladalean architectures may be derived from a single
Cladophora-like ancestor.
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