Using of phytoplankton compiled with hydrographical parameters as

indicator of pollution in El-Timsah Lake, Ismailia, Egypt.

Abeer Shaker Amin

Botany Department, Faculty of Science, Suez Canal University, Ismailia, Egypt

ABSTRACT Biological studies and hydrographical parameters are compiled to assess the

environmental status of El-Timsah lake. The lake subjected successive shrinking due to

human activities, including construction of navigation pavements, buildings, recreation

centers required for development planning. Samples were collected from six sites covering

the lake during the period summer 2005-spring 2006, representing the four seasons, including

water and phytoplankton samples, in order to evaluating phytoplankton algal community and

hydrographic parameters. A total of One-hundard and two taxa have been identified. Most of

them belong to Chlorophyceae (8); Bacillariophyceae (56); Dinophyceae (18); Cyanophyceae

(20) were recrded. The maximum occurrence of the total phytoplankton density (1788 & 1718

cells.l-1

) was recorded in winter at sites I and II. The productivity was high for Bacillariophyta

(60.2 & 59.5 %) and cyanophyceae (19.3 & 19.7 %) which may be attributed to

concentrations of NH4 - N, PO4 -P and NO3-N, NO2-N and relatively higher values of salinity

(33.8-32.2 ppt). Where the species richness (Alpha Diversity) was ranged between 6.586

during summer and 14.287 in winter while relative evenness (H') was fluctuated between

1.684 in summer and 1.902 in winter Chlorophyll a varied between 0.3 at site I and 26 µg.l-1

at site II. It exhibited high values during winter, while the lowest one during summer.

Abundance of phytoplankton species may be attributed to High PO4, lower water temperature,

and NH4–N and NO3–N were relatively high. The N:P ratio in Lake-Timsah, ranged between

1.07 and 9.45. The lowest value occurred at sites I, II and IV This could be attributed to

eutrophication caused by wastewater and domestic input into the lake. This result indicate that

The Lake Timsah classified as eutrophic where The N:P ratio is lower in eutrophic than

oligotrophic lakes. The result also was confirmed by the presence of some algal

phytoplankton species are known to be a highly tolerant organic pollution and others as

pollution indicators Most of the phytoplankton species recorded in this study was registered

as pollution indicator species, others as toxigenic species for human beings and producing

odor compound that impart water quality.

ITRODUCTION

Algal bioindicators and bioassay methods are very well suited for analyzing

autoecological, as well as synecological problems, by combining

hydrographical, and biological measurements to glean relevant information for

the management of coastal waters (Palmer, 1980; Baruah, and Das, 2001).

Different stages of the life history of a species can also be affected differently by

pollution (De Lange, 1994). Furthermore, species diversity in itself is not

necessarily a reliable estimator of water quality; the cleaner the water, the more

extreme the environment, which can then induce low species diversity. "Pure

water would not be a good medium for algal growth"! Moreover, mild pollution

could have an enriching effect. Growth, productivity, biomass, and

reproduction/fitness measurements have frequently been used as laboratory or

field bioindicator to evaluate levels of pollution (Dale, 2001). Algal species

tolerant to organic pollution are significant in the recovery of a stream or lake

because they add oxygen to the water during photosynthesis and incorporate

organic and inorganic nutrients into their cells, thus removing pollutants from

the water (Diaz, et al., 1998).

Ecology is the study of relationships between organisms and their

surroundings. This study is fundamental to an understanding of biology because

organisms cannot live as isolated units. The activities which comprise their lives

are dependent on, and closely controlled by, their external circumstances, by the

physical and chemical conditions in which they live and the populations of other

organisms with which they interact (Moss, 1998). Phytoplankton represents the

basis of the food chain within many environmental habitats and forms an

essential food for many filter-feeding animals (Boney, 1989). It was found in

almost every habitat in environment and in every kind of water habitats.

Phytoplankton consists primarily of different groups (Chapman & Chapman,

1988). No phyla are confined to freshwaters but fifteen phyla are found only in

the ocean. This distinction probably applies even more to the numbers of species

present (Moss, 1998). The composition and distribution of species ( in both the

Red and the Mediterranean Seas and in the Canal) could be a strong indicator of

the current regime in the Suez Canal (Madkour, 2000).

The first record on phytoplankton distribution throughout the Canal was

made by MacDonald (1933), six genera of diatoms with 17 taxa and 5 genera of

dinoflagellates with 13 taxa were recorded. Ghazzawi (1939) identified 43

diatom species and 17 dinoflagellates in phytoplankton samples collected from

the canal. Distribution of phytoplankton with emphasis of seasonal distribution

of diatoms along the Suez Canal was studied by (Dorgham, 1974, 1985, 1990).

Further study on the total phytoplankton species in the canal reveled the

occurrence of 182 diatom species, 88 dinoflagellates, and 1 species of

silicoflagellates (Dowidar, 1976). El-Sherief and Ibrahim (1993) identified 94

species of diatom and 36 of dinoflagellates from the entire Canal . Madkour

(1992, 2000) discussed the structure, dynamics and the relationships between the

hydrographic conditions of the Suez Canal and the distribution and abundance

of phytoplankton species. On the other hand, Gab-Allah (1985) studied the

species composition and monthly abundance of phytoplankton in Lake Timsah.

EL-Manaway, (1987) discussed the ecology of seaweeds of the Suez canal and

the result indicated that the marine flora of lake Timsah comprised about 80

species of seaweeds, 10% are blue green, 28% are green algae, 14% are brown

algae and 46% are red algae.

Distribution of phytoplankton is useful for the general monitoring of

certain aspects of the environment, such as hydrogaphic events, eutrophication,

pollution, warming trends and long-term changes which are signs of

environmental disturbances (Moss, 1998). These aspects affect other important

biological research, like fisheries investigation. The major objectives of this

study are to investigate the phytoplankton community and its distribution within

Lake Timsah and the relationships of the different communities to various

hydrographical parameters. In addition to study the effect of pollution on the

quality of water and phytoplankton populations and their seasonal distribution

and abundance in Lake Timsah with emphasis on use of phytoplankton algal

species for bio-monitoring of water pollution.

Materials & Methods

Study area

Lake Timsah is a saline shallow-water basin with an average depth of

about 6 m. and a surface area of about 15km2. It is located nearly half way along

Suez Canal between 30° 13' 00" to 32° 35' 18" North and 32° 16' 30" to 32° 18'

30" East. The lake was a swamp which, long ago, used to be flooded by Nile

waters at very high floods through the Tumilat valley. This site receives sewage

water from the sewage canal passing behind C hevalier Island. The lake receives

fresh water through the Ismailia Canal, in addition to fresh water drains from

neighboring cultivated land which open into some of the western lagoons

communicating with the lake. This fresh water has been reported to reduce the

surface salinity to about 35 ppt (El-Sabh, 1969). Six sites were chosen for

regular sampling, representing different habitats in the Lake (Figure 1). Site I

(Taawen Beach) is near the beach club at the southern entrance of the lake, This

site is characterized by a lot of mixing and currents caused by the passage of

ship Site II (Fayrooz Beach) and III (Bridge) at the western part of the lake, and

received pollution from fishing and human activities through tourism villages.

Site IV (Chevalier Island) at the northern entrance of the Lake ,it receives

sewage water from the sewage canal passing behind Chevalier Island. Also this

site receives an amount of fresh water from the Ismailia fresh water Canal

through mitre gate at this outlet. Site V (North -EL-Timsah 1) and VI (North-

EL-Timsah 2 ) are located at northern east of Lake and receives a little source of

pollution when compared with other sites along the Lake.

Sampling of water

Sampling started in, summer 2005 and was carried out seasonally until

spring, 2006. Samples (2 L) were collected from 6 sites by water sampler.

Seasonally monitoring was found sufficiently enough to allow colonization and

stabilization of algal populations. Subsurface water samples were taken at all

sites. Four replicates were collected from different sites surrounding each

sampling site at different distances. These replicates were mixed together and

again divided into 4 or more portions. Water temperature, pH, and fixation of O2

for subsequent analysis were recorded in the field at the sites of collections.

Water samples for hydrographical parameters were collected in polyethylene

bottles of one liter capacity, and laboratory analysis started within few hours

from the time of collection.

(Figure 1): Location of sampling sites along Lake Timsah

Hydrographical Parameters analysis

Portable field meters were used to record the subsurface water

temperature (glass mercuric thermometer (110°C with 0.5

°C graduation),

oxygen (Oxygen-meter, Cole Parmer model 5946-70), pH (Digital pH-meter,

Cole-Parmer, model 5938-50), turbidity (Turbidity-meter, Chemtrix, Type 12

FSc) and conductivity (Conductivity-meter, Chemtrix Type 700). Water samples

for other parameters and chlorophyll a were collected in polyethylene bottles

and laboratory analysis was started within few hours from the time of collection.

Analysis of water included alkalinity, chemical oxygen demand (COD), silicate,

nitrate, nitrite, ammonia, and phosphorus. Analysis is based on the methods

recommended by the American Public Health Association (1985). Dissolved

oxygen (DO), biological oxygen demand (BOD) and ammonium (NH4-N)

samples were collected first from Nisken’s bottle then fixation was carried out

for each of DO and NH4-N samples just after collection. DO was determined (to

calibrate that of the probe) at the same day of collection using the classical

1km

1

2

3

4 5

6

N

Lake Timsah

Winkler method. DO samples was measured initially and after incubation for 5

days at 20 °C. The BOD values were calculated from the differences between

the initial and final DO concentrations. Chlorophyll "a" was measured using the

method given by the APHA (1995).

Phytoplankton Sampling

Phytoplankton samples were preserved in 500 ml glass bottles with lugol's

solution. The technique developed by Utermohl (1958). The preserved samples

with Lugol's solution were concentrated to 100 ml by decanting, species

identification (X500-X1000 magnification) and cell counting (X100

magnification) were made with an inverted microscope; an Olympus 1X70

equiped with Panasonic color monitor TC-1470 Y. Also, live samples for

identification of some phytoplankton were collected.

Sedjweck-rafter cell was also repeatedly used for cell counting (APHA

1985).. The standing crop was then calculated as the number of cells per liter.

Qualitative analysis was carried out using the preserved as well as fresh

samples. These were examined microscopically for the identification of the

present genera and species. Concerning diatoms, it was necessary to clear it

using conc. H2SO4, to be well identified. The algal taxa were identified

according to the following references: Hustedt (1930-1937), Desikashary

(1959), Hendey (1964), Vinyard (1975), Taylor (1976), Humm and Wicks

(1980), Bourrely (1968), Prescott (1978), Sykes (1981), Van-Heurck (1986),

Hindak (1984, 1988, 1990) and Tomas (1997).

Data Analysis

Species richness (alpha diversity) was calculated for each phytoplankton

algal group as the average number of species per seasons. Species turnover (beta

diversity) was calculated as a ratio between the total numbers of species in

certain algal group and its alpha diversity. Relative evenness (H': Shannon-

Weiner index) and relative concentration of dominance (C: Simpson's index)

were expressed according to the following equations:

H' = -Σ s Pi (log pi) and C = Σ

s (Pi)

2

i = 1 i = 1

where "s" is the total number of species and 'Pi' is the relative importance value

(relative cover) of the ith

species ( Whittaker, 1972; Pielou, 1975; Magurran,

1988).

Results and Discussion

Environmental parameters

The minimum & maximum values of hydrographical parameters are present in

Table (1). The seasonal variations of them are represented in Figures (2 a-i ).

Table (1). Range of change in some physicochemical parameters of water -

El-Timsah Lake- at different sites during the period Summer 2005-

Spring 2006.

Sites Site I Site II Site III Site IV Site V Site VI

Parameters Min Max Min Max Min Max Min Max Min Max Min Max

Temperature °C 14 29 14 29 14.5 29.5 14.5 29.5 15 31 15 31.5

pH 7.4 8.5 8 8.8 8.6 8.9 7.9 8.4 7.3 7.9 7.2 7.9

Conductivity µmohs.cm-1

42.5 52.5 51.5 78 77 85 42 67.1 68 107 79 90.2

Salinity ppt 33.8 41.9 32.2 44.6 33 43.8 31.4 42.7 41.2 44.9 39.9 44.8

Turbidity m 2.6 2.9 2.8 2.9 2.2 2.6 1.8 2.4 0.24 0.45 0.39 0.5

Dissolved Oxygen mg.l-1 7.2 8.4 7.3 10.2 6.2 8.9 5.6 9.6 6.3 9.8 7.1 8.8

Nitrate µg.l-1

15.6 114.1 29.5 130 53.2 112.2 32 130.4 32.2 98.4 28.2 92

Nitrite µg.l-1 2.7 25.2 1.4 19.2 1.3 22.1 1.1 19.1 1 10 1 13

Ammonium µg.l-1

118 253 121 188 115.3 159.3 112 157.2 98.3 148 92.2 134.9

Phosphate µg.l-1

13.2 20.4 12.2 29.6 13.7 28.5 10.5 26.2 12.2 26.8 6.9 25.9

Silicate mg.l-1

3.4 6.6 3.8 6.4 3.3 5.8 3.1 5 2.7 6.7 3.4 6.8

Chlorophyll a µg.l-1

0.3 24 2.8 26 3.2 18.1 4.2 16 3.9 17.9 4.7 19.3

N: P ratio 1.07 5.59 1.8 5.82 2.8 4.75 2 6.74 1.98 4.8 2.03 9.45

The lowest water temperature registered in winter (14°C) and the highest was

(31.5°C) detected in summer at most sites. pH values recorded in the lake fall in

the alkaline range (7.2 – 8.9). Conductivity varied between 42 at Site IV and 107

µmohs.cm-1

at site V. Its highest values recorded in summer and the lowest in

winter. Salinity reached its maximum value (44.9 ppt) in summer and its

minimum value of 31.4 ppt in winter. Their lowest readings (31.4 – 32.2 ppt)

registered at sites IV & II due to the fresh water discharge from sewage drainage

and the village tours settled at these sites, while its highest readings (44.9 – 44.8

ppt) recorded at sites V & VI at the northern east of the lake. Miller & Munns

(1974) stated that salinity will be always high and often complete dissolution of

the salt bed, due to the high evaporation rate. However, the recent uncontrolled

development in and around the lake and the discharge of sewage drainage

increases the fresh water into the lake and consequently the salinity may be

reduced. Turbidity ranged from 0.24 to 2.9 m. The euphotic zone does not

extend to the bottom in these regions. This may be due to the movements of the

ships in this area and the high density of phytoplankton which cause the water to

be turbid. In other sites in the northern east side, the photic zone may extend to

the bottom. Dissolved oxygen in the surface water fluctuated between 5.6 mg O2

l-1

at site IV and 10.2 mg O2 l-1

at site II. Its lowest values recorded in summer

and the highest during winter. NO3-N concentrations ranged between 15.6 µg.l-1

at site I and 130.4 µg.l-1

at site IV. It exhibited high values during winter, while

the lowest one during summer. The source of high concentration is due to

organic matter supply carried with fresh water from domestic sewage from the

tourism villages on the western side of the lake. NO2-N concentrations remained

below 25.2 µg.l-1

in all seasons along the selected sites with the exception of

winter season which recorded the highest value. NH4 –H values in all sampling

sites varied between 92.2 µg.l-1

at site VI and 253 µg.l-1

at site I. It had higher

values in winter and autumn. PO4-P which forms about 5% of the total

phosphorus in a lake (Wetzel, 1983), and is the most available form for

phytoplankton. PO4-P levels as compared with (Gab Allah, 1985), doubled in

the past decades. This is could be attributed to eutrophication caused by waste &

input of drain terminating in the lake along the western side. It reached its

maximum value 29.6 µg.l-1

at site II in winter and its minimum value of 6.9 µg.l-

1 at site VI during spring. SiO3-Si values fluctuated between 2.7 mg.l

-1 at site V

and 6.8 mg.l-1

at site VI. Its highest values occurred in spring and the lowest in

autumn. The importance of the element lies in its significance for the

construction of the cell wall of diatoms. This element is not a limiting factor for

diatoms in the lake. Willem (1991) reported dissolved silica content between

0.03 mg.l-1

and 0.20 mg.l-1

as limiting level for diatom growth.

The N:P ratio in the water is an important variable since it can denote which of

these nutrients appears to be in excess for phytoplankton growth. Redfield

(1958) found an average ratio of 15 in oceans, a value that also applies to

freshwater. Unicellular algae such as phytoplankton and benthic microalgae

have an elemental ratio of carbon to nitrogen to phosphorus (C/N/P) of

approximately 106:16:1. (Baird, and Middleton, 2004). In Lake-Timsah, the

ratio ranged between 1.07 and 9.45. The lowest value occurred at sites I, II and

IV This could be attributed to eutrophication caused by wastewater and

domestic input into the lake. In this connection Knuuttila et al.(1994), stated

this ratio is lower in eutrophic than oligotrophic lakes.

0

5

10

15

20

25

30

35

Site I Site II Site III Site IV Site V Site VI

Sites

°C

Summer 05 Autumn 05

Winter 06 Spring 06

0

10

20

30

40

50

Site I Site II Site III Site IV Site V Site VI

Sites

pp

t

Summer 05 Autumn 05

Winter 06 Spring 06

(a )Temperature °C ( b ) Salinity ppt.

0

0.5

1

1.5

2

2.5

3

3.5

Site I Site II Site III Site IV Site V Site VI

Sites

m

Summer 05 Autumn 05

Winter 06 Spring 06

0

2

4

6

8

10

12

Site I Site II Site III Site IV Site V Site VI

Sites

mg

.l-1

Summer 05 Autumn 05

Winter 06 Spring 06

(c ) Turbidity m ( d ) Dissolved oxygen mg.l

-1

0

20

40

60

80

100

120

140

Site I Site II Site III Site IV Site V Site VI

Sites

µg

..l-

1

Summer 05 Autumn 05

Winter 06 Spring 06

0

5

10

15

20

25

30

Site I Site II Site III Site IV Site V Site VI

Sitesµ

g..

l-1

Summer 05 Autumn 05

Winter 06 Spring 06

(e ) Nitrate µg.l

-1 ( f ) Nitrite µg.l

-1

0

5

10

15

20

25

30

35

Site I Site II Site III Site IV Site V Site VI

Sites

µg

.l-1

Summer 05 Autumn 05Winter 06 Spring 06

0

1

2

3

4

5

6

7

8

Site I Site II Site III Site IV Site V Site VI

Sites

mg

.l-1

Summer 05 Autumn 05

Winter 06 Spring 06

(g ) Phosphate µg.l

-1 ( h ) Silicate µg.l

-

0

5

10

15

20

25

30

Site I Site II Site III Site IV Site V Site VI

Sites

µg

.l-1

Summer 05 Autumn 05

Winter 06 Spring 06

0

2

4

6

8

10

Site I Site II Site III Site IV Site V Site VI

Sites

N:P

ra

tio

Summer 05 Autumn 05

Winter 06 Spring 06

( j ) Chlorophyll a µg.l

-1 (i ) N: P ratio

Figure 2 (a-i): Seasonal variations of some physicochemical parameters

along different sites

Biological parameters

Chlorophyll a

Phytoplankton biomass that is represented by chlorophyll a varied between 0.3

at site I and 26 µg.l-1

at site II (Table 1). It exhibited high values during winter,

while the lowest one during summer (fig 2 j). Its concentration is reflecting the

number of individuals and increasing of nutrients.

Species composition and population density

The result suggested the presence of phytoplankton continuum in the area with

dispersion of some species in certain microhabitat conditions. A total of 102

taxa have been identified (Table2). Most of them belong to Chlorophyceae (8);

Bacillariophyceae (56); Dinophyceae (18); Cyanophyceae (20). while the

distribution of phytoplankton species among the algal groups of Lake Timsah

explained in (Fig.3). The seasonal variation of these groups presented in (Fig.4)

and Table(4) showed the range of variation in some diversity indices calculated

of the phytoplankton algal group per seasons where the species richness (Alpha

Diversity) was ranged between 6.586 during summer and 14.287 in winter while

relative evenness (H') was fluctuated between 1.684 in summer and 1.902 in

winter while ( C ) value was measured as 0.015 in winter and 0.033 in summer .

The maximum occurrence of the total phytoplankton density (1788 & 1718

cells.l-1

) was recorded in winter at sites I and II (Fig.4) and can be attributed to

concurrent increase of Bacillariophyceae (60.2 & 59.5 %) and cyanophyceae

(19.3 & 19.7 %) which may be attributed to concentrations of NH4 – N, PO4 – P

and NO3 – N, NO2 -N and relatively higher values of salinity (33.8-32.2 ppt).

The blooming of Bacillariophyceae and Cyanophyceae developed when the

concentration of PO4 – P and NH4 – N are high and NO3 – N is comparatively

low (Abdul Hussein and Mason, 1985), and according to Greenwald &

Hurburt (1993), stated that the phytoplankton abundance increases as salinity

ranges from ( 17-42 ‰). This statement seems to be in agreement with our

results.

Table (2) . Species composition of phytoplankton in El-Timsah Lake - Suez

Canal- Egypt during the study period ( Summer 2005- Winter 2006)

Chlorophyceae

1. Actinastrum hantzschii Lag

2. Ankistrodesmus falcatus (Corda) Ralfs *

3. Cladophora crispata (Roth) Kϋtzing

4. Cosmarium panamense Prescott

5. Kirchnerilla obesa (W. West.) Schem.

6. Scenedesmus quadricauda* (Turp.) De

Breb.

7. Tetraedron minimum (A.Br.) Han.

8. T. Trigonium (Naeg.) Han.

Bacillariophyceae

1. Achnanthes brevipes var. brevipes Agardh

2. Achnanthes lanceollata (Breb.) Hϋst.

3. Amphiprora alata Kϋtz.

4. A. paludosa W. Smith

5. Amphora ovalis var. ovalis Kϋtzing

6. Astrionella formosa Hass.

7. A. japonica Cleve

8. Bacillaria paradoxa Gmelin

9. B. paxillifer (O.F. Mull) Hendey

10. Biddulphia mobiliensis (Bail) Grun. Ex.

Van Haurk

11. Chaetoceros didynus Ehrenberg

12. Coscinodiscus lineatus Ehrenberg

13. Cocconeis placentula Ehrenberg

14. C. scutellum Ehrenberg

15. Cyclotella comta (Ehr.) Kϋtzing *

16. C. glomerata Bachmann. *

17. C. meneghiniana kϋtz. *

18. C. ocellata Pant. *

19. Cymatopleura solea Breb.

20. Cymbella ventricosa var. ovata (Agardh)

Kϋtzing

21. Diploneis ovalis (Hilse) Cl

22. Fragilaria crotonensis Kitton

23. Gomphonema parvulum var. parvulum

(Kϋtzing) * Grunow

24. G. ventricosum Gregory. *

25. Gyrosigma attenuatum (Kz.) Rabh.

46. Skeletonema subsalsum

47. Stauroneis anceps Ehrenberg

48. Stephanodiscus hantzschii (Grim.)

49. Surirella angustata Kϋtzing

50. Surirella clypus Kϋtzing

51. S. ovalis var. ovata Kϋtz.

52. S. robusta Ehr.

53. Synedra acus var. radians Ehr. *

54. S. ulna var. ulna (Nitzsch.) Ehr. *

55. Tabellaria fenestrata ( Lyngb.)

56. Thalassionema nitzschoides Grun.

Cyanophyceae

65. Anabaena bergii (Kissel.) Ka. (O)

66. A. Constricta (Szalf) Geitler. (O)

67. A. variabilis Kϋtzing (O)

68. Arthrospira jenneri Stizen ex. Gom.

69. Chroococcus. Limneticus Lemm.

70. C. turgidus (Kϋtz.) Nägeli

71. Merismopedia tenussima Lemm.

72. Microcystis elabens (Bréb.) Kϋtz. (O)

73. Oscillatoria chalybea (Mert) Gom. **(O)

74. O. limosa Ag.Ex. Gom. ** (O)

75. O. planktonica Woloszynksa ** (O)

76. O. subtilissima Kϋtz. ** (O)

77. O. subuliformis Kϋtzing ** (O)

78. Phormidium molle Kϋtzing (Gomont) *

79. Pseudoanabaena limnetica (Lemm.) Kom.

80. Spirulina major Kϋtzing

81. S. subsalsa Ostred.

82. S. subtilissima (Kϋtz.) ex. Gom.

83. Synechocystis salina Wisl.

84. Tetrapedia reinchiana Archer

Pyrrhophyceae

85. Amphidinium acutum Loh.

86. A.henoides Wulff

87. Ceratium egyptiacum Halim

88. C.xtensum (Gour.) Cl.

89. C. furca (Ehr.) Claparéde and Lachmann

26. G. scalproides (Rabh.) Cleve.

27. Melsira granulata var. granulata (Ehr.)

Ralfs *

28. M. nummuloids (Dillw) Ag.*

29. Navicula abrupta Gregory

30. N. cardinalis Ehrenberg *

31. N. cryptocephala Kϋtz.*

32. N. dicephala (Ehr.) W.Sm.*

33. N. digitoradiata *

34. N. Hungarica Grun.*

35. N. Salinarum Grun. *

36. N. viridula var. viridula Kϋtz. *

37. Nitzschia acicularis W. Smith. *

38. N. closterium (Ehr.) W. Sm. *

39. N. Panduriformis Ehr. *

40. N. Pseudo-delicatissima Hasle. *

41. N. punctata (W.Sm.) Grun. *

42. N. obtusa W. Sm. *

43. N. sigmoidea (Ehr.) W.Sm. *

44. Rhizosolenia fragilissisma Berg.

45. Rhopalodia gibba (Ehr.) Mϋller

90. C. tripos (Mϋller) Nitzsch

91. Dinophysis caudata Saville-Kent (X)

92. Exuviella compressa Ostef

93. Gymnodinium mitratum Schil.

94. G. Simplex Loh.

95. Peridinium cerasus Paulsen

96. P. pulchellum Paulsen

97. Prorocentrum compressum (Baily)ABFP

& DoDge

98. P. dentatum Stein.

99. P. gracile Shutt.

100. P. minimum (Pavillard) Schil.

101. P. scutellum Schröder

102. Protoperidinium oceanicum Van.Hofen.

** High organic pollution tolerance

* Less organic pollution tolerance

(X)Toxic species

(O) Producing Odor compound in water

0.00%

10.00%

20.00%

30.00%

40.00%

50.00%

60.00%

Chloro. Bacillario. Cyano. Pyrrho.

Figure ( 3) Distribution of phytoplankton species among the algal groups of

Lake Timsah

Table (3). The population density of algal groups and their percentage

abundance to total cell numbers of phytoplankton throughout the study

period at various sites

Sites Site I Site II Site III Site IV Site V Site VI

Seasons Total % Total % Total % Total % Total % Total % Chlorophyceae

Summer 05 18 2.12 21 2.6 21 2.8 16 2.4 17 3.2 12 2.9 Autumn 05 46 4.3 56 5.7 46 5.8 39 4.6 25 3.9 29 5.6 Winter 06 121 7.04 132 7.4 116 6.9 95 6.2 69 6.2 80 8.8 Spring 06 28 2.2 37 3.01 35 2.8 30 2.6 26 2.8 30 4.2

Bacillriophyceae Summer 05 484 57.1 419 51.04 363 47.6 318 48.5 184 34.5 154 37.6 Autumn 05 534 50.5 485 49.2 354 44.5 399 47.1 240 37.6 182 35 Winter 06 1035 60.2 1064 59.5 983 58.4 878 57.6 616 54.9 475 52.4

Spring 06 492 38.02 470 38.2 460 37.3 392 33.4 274 29.8 192 27.1

Cyanophyceae Summer 05 45 5.3 44 5.4 51 6.7 31 4.7 24 4.5 19 4.6 Autumn 05 229 21.7 196 19.9 172 21.6 153 18.07 120 18.8 97 18.7 Winter 06 332 19.3 352 19.7 340 20.2 294 19.3 220 19.6 170 18.8

Spring 06 113 8.7 104 8.5 135 10.9 96 8.2 81 8.8 51 7.2

Pyrrhophyceae Summer 05 301 35.5 337 41.05 327 42.9 291 44.4 308 57.8 225 54.9 Autumn 05 249 23.5 249 25.3 224 28.1 257 30.3 253 39.7 212 40.8 Winter 06 230 13.4 240 13.4 245 14.5 258 16.9 217 19.3 181 19.9 Spring 06 661 51.1 620 50.4 604 48.9 655 55.8 539 58.6 435 61.4

0

500

1000

1500

2000

Site I Site II Site III Site IV Site V Site VI

Sites

No

. o

f cell

s.l-

1

Summer 05 Autumn 05

Winter 06 Spring 06

Figure (4). The seasonal variation of algal groups during the study period

( 2005-2006)

The percentage contribution of chlorophyceae to the total phytoplankton density

fluctuated between 2.12 % at site I during summer (Table 3) when salinity and

water temperature were high (Figs 2a & b ) and 8.8 %, 7.04 % respectively at

site VI and II during winter when PO4 – P, NO3 –N were relatively high where

they receive organically polluted water from domestic sewage and recreational

swimming. Scenedesmus quadricauda (Turp.) de Breb and Actinastrum

hantzschii (Lagerh) were the most dominant species in winter and the former

species are considered as less organic pollution tolerant (Palmer 1969). They

are known to be common in various conditions of sewage ponds, Gray (1989).

Table(4) Variation in some diversity indices calculated of the

phytoplankton algal group per seasons in the study area

Statistical Analysis Summer 05 Autumn 05 Winter 06 Spring 06

Total Number of Species /Season 87 100 102 96

Relative Evenness (H') 1.684 1.846 1.902 1.732

Simposons Diversity (C) 0.033 0,017 0.015 0.027

Species Richness ( Alpha Diversty) 6.586 7.917 14.287 10.716

Beta Diversity 13.2 12.6 7.1 9

Bacillariophyceae constituted the dominant algal groups in terms of cell

numbers and taxa. This was also recorded by Gab Allah (1985&1991) on Lake

Timsah & Manzalah, this may be due to their tolerance to salinity. The

minimum occurrence of diatom observed during spring (27.1% ), while the

maximum one (60.2 %) recorded in winter when water temperature was 14 °C,

NH4 – N and NO3 – N were relatively high Figs. (2 a & e) when compared to

PO4-P concentrations (Fig 2 g). The increase in populations of this group at high

nitrogen concentrations and low temperatures agrees with the findings of

Tilman et al.(1986), who stated that diatoms are good competitions for

phosphorus but weak competitors for nitrogen.

Among the dominant species of diatoms were Thalasssionema nithzschoides

Grum, Nithzchia pseudo delicatissima Hasle (less organic pollution tolerance)

and Nitzzschia closterium (Her.) (less oraganic pollution tolerance) W. Smith.

Thalassionema nithzschoides (Grum.) which was recorded by Gab-Allah

(1985), in Timsah lake is known as an indicator of high nutrient conditions and

tolerate extreme variable conditions (Van Tprene et al., 1987). Its peak

occurred in summer at all sites when water temperature and salninty were high.

Nithzchia pseudo delicatissima Hasle is geographically widely distributed

genus restricted to marine plankton (Tomas, 1997). It is worth mentioning that

at the time of predomination of this genus, it produces domoic acid (Martin et

al., 1990) Domoic acid may be a worldwide threat on temperate coasts.

The algae are affected by pollution in different ways. They may be

discouraged from growing as a result of being the deprived of sun light, the

substances may be toxic or may ecologically modify the physical or chemical

environment sufficiently to retard or prevent their growth. They may suddenly

have competition with additional organisms; certain algae may be stimulated to

increase growth and multiplication. A change may also occur in the individual

types or the groups of organisms that predominate (Palmer, 1969; Danilov, and

Ekelund, 2001).

Cyanophyceae constituted the second important group in terms of cell numbers.

Being dominant in Autumn (21.7 %) and winter (20.2 %). Its high regional

occurrence observed at SitesI, II and III during the study period and this may be

attributed to High PO4. Anabaena bergii (Kissel.) Ka., Oscillatoria chalybea

(Nert.) Gomont (high organic pollution tolerant), Spirulina major and

Phormidium molle were the most dominant species. Confirming our results,

Gab Allah (2001) stated that Oscillatoria chalybea (Nert.) Gomont and

Phormidium molle were the most dominant species in marine water. Some

species of blue green algae are able to develops a foul odor and taste, and can

even become toxic in water habitats. (Hyenstrand, 1999). Anabaena,

Aphanizomenon, Microcystis, Nodularia and Oscillatoria have been reported as

toxigenic species responsible for acute lethal poisonings for animals (Sivonen,

1996; Carmichael, 1998; Gomaa et al., 2000) and may be a health hazard for

human (Codd et al., 1999).

Dinophyceae increased during spring due to the luxuriance growth of

Prorocentrum compressum, P. dentatum Stein , P. gracile, and P. minimum

(Pav.) Sch.. Dinophysis caudata Saville-Kent (are known as a toxigenisc

species in marine water bodies (Hallegraeff et al., 1991; Oshima, et al., 1993)

Ceratium furca Her. and Exuviella compressa was dominant throughout the

study period but in few numbers. Protoperidinium oceanicum Van Hoffen

showed an increase of 62-99cells.l-1

in summer in all sites when salinity and

temperature were high. This dinoflagellate are known for its euryhalinity

(Smayda, 1983), and relatively high temperature tolerance (Boney, 1975)

One of the plankton ecologist's main goals is to identify what factors influence

the distribution, abundance and species composition of plankton. This goal is

made difficult by the complexity of natural marine environments. A useful

approach is to examine habitats that differ in as few respects as possible, the

differences seen in the plankton can be attributed to these differences in habitat,

and used as a basis for experiments designed to attach cause to effect

(Kimmerer and Mckinnon, 1985). These were the basis of the present

investigation which paid special attention to phytoplankton, the most important

planktonic plants in Lake Timsah.

Lake Timsah, according to the lake classification proposed by Thienemann

(Komarovsky, 1959) has characteristics that fit it into the eutrophic class.

However, Gab-Alla (1985) concluded that the lake falls within the oligotrophic

category. However, this was not strictly the case in a further study upon lake by

Sharaf, 1990. It was appear that Lake Timsah was a less eutrophic lake,

compared to all other lake in the same climatic region, for it had the physical,

chemical and biological features of eutrophic lakes though it was not as highly

productive as the Delta lakes, and this results not in agreement with our result in

this study.

Conclusions

The present study is essentially providing a base information concerning

the population density and species composition if phytoplankton in relation to

the hydrographical parameters of Timsah-Lake, mandatory for further

hydrographical, biological and geological studies carefully and frequently due to

the over-exploitation of economic and tourism activities. The hydrographical

parameters analysis indicate that water in this Lake remains polluted throughout

the year with slight self purification capacity at site V and VI Moreover, the

study provides a sort of data-base necessary for water lake management and

predictions for further evaluations of ecosystems. Most of the phytoplankton

species recorded in this study was registered as pollution indicator species,

others as toxigenic species for human beings and producing odor compound that

impart water quality.

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لملخص العربىا

أستخدام الهائمات النباتية والعوامل الهيدروجرافية كدالئل للتلوث فى بحيرة التمساح

مصر . األسماعيلية ب

عبير شاكر أمين

قسم النبات -جامعة قناة السويس –كلية العلوم

ل حديةد هذه الدراسةة هدةدا الةر سراسةة العوامةي البيولوجيةة ممة اكة مةل العوامةي الديدر جاا يةة

لألنمةةة ل غياات بيئية كثياة كن يجة طبيعيةةحيث أن هذه البحياة هعاضت . الحالة البيئية لبحياة ال مساح

بناء علر هذا هم .بعد بناء العديد من القاى السياحية المواطئ بدذه المنةقة خي األنسان ل د الحضاية

عظةم أجةءاء البحيةاة خةلف ال ةاة مةن ةي هجميل عينات مياه هائمات نباهية مةن سة ة محةةات همثةي م

هحليةي العوامةي ذلك لحصا مح وى كةم الدائمةات النباهيةةليمثي أربل صوف 5002ح ر ربيل 5002

, نوعةة 205 سلةةت الن ةةائ أن عةةدس أنةةواا الدائمةةات النباهيةةة ال ةةر سةةجلت ةةر هةةذه ال ةةاة . الديدر جاا يةةة

22) مجموعةةة الةةدياهومات , ( أنةةواا 8) ةحالةةا الرضةةااء معظةةم هةةذه األنةةواا هن مةةر الةةر مجموعةةة ال

سةجلت . الةحالا الرضااء المءرقة ه مثي بعماين نوع ( نوا 28) مجموعة الدينو لجيلت , ( نوا

5, 2 ةر صةي المة اء ةر المحةةة رقةم ( خلية لكي ل ا 2188, 2128) كثا ة األنواا للدائمات النباهية

مجموعةةة % ( 2..2., 20.5)أن عةةام مجموعةةة الةةدياهومات ال ةر همثةةي نسةةب دا هةذا ياجةةل الةةر يةاسة

الةةذى ياجةةل الةةر أح مةةاف يةةاسة % ( 1..2, 1..2) الةحالةةا الرضةةااء المءرقةةة ال ةةر همثةةي نسةةب دا

11.8 – 15.5) مونيوم ال وس ات الني ةاات الني ايةت الةر الءيةاسة الة ي ةة ةر الملوحةةاألهاكيءات

خةةلف 2.282بةةين ( أل ةةا -أخ ل ةةات ) هاا حةةت الن ةةائ األحصةةائية لكثا ةةةاألنواا . (البليةةون جةةءء ةةر

ةر الصةي كةان ةر 2.288بةين ( ح')معةدف ال واجةد هاا حبينما 28.581الصي كانت ر الم اء

نةت هاكيءاهة كا 2 ر المحةة رقةم .,1هاكيءات الكلور يي هاا حت بينبينما . 05..2. الم اء يسا ى

ميكا جةةاام لكةةي ل ا كانةةت أعلةةر ال اكيةةءات ةةر صةةي المةة اء سةةجلت أقةةي ال اكيةةءات ةةر صةةي 52

ياجل ياسة األنواا مةن الدائمةات النباهيةة ال ةر سةجلت الةر يةاسة ال وسة ات قلةة سرجةة حةاارة الصي

ةر 82..الر 2.01اا حت بين ا جين الر ال وس ور قد هينالأما نسبة . ياسة الني اات الني ايت الماء

هةذا يمكةن أن ياجةل الةر 5 2 قد كانت أقي معدالهدا ةر المحةةة رقةم ( محي الدراسة)بحياة ال مساح

ف الصةاا د ياسة الملوثات ر ورة ياسة االمواس المغذية الدائمات النباهية الذى ياجةل الةر يةاسة معة

هصن علةر أندةا منةقةة ذه الن ائ هؤكد أن بحياة ال مساح ه. الصحر هدخي األنسان السلبر ر البحياة

حيةث أن نسةبة الن ةا جين الةر ال وسة ور ( ن يجة لءياسة المواس المغذية الدائمات النباهيةة )غنية بالملوثات

هذه الن ائ أيض سعمت ب سجيي أنواا . يكون أقي ر المناطق الغنية بالملوثات عن المناطق قليلة ال لوث

عةاي ةر منةاطق غنيةة بالملوثةات العضةوية لدائمات النباهية هع با كدالئي لل لوث بعضةدا كمحةا للمن ا

قد هم هسجيي أنواا أيض من الدائمات النباهية من المعا ا أندا ه ا مواس سامة هؤثا سلبي علر األنسان

. بعضدا ي ا ماكبات ضارة هغيا من رائحة المياه