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 NH 4 - N, PO 4 -P and NO 3 -N, NO 2 -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 PO 4 , lower water temperature, and NH 4 –N and NO 3 –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
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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
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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