18
F. A. Khan et al.
2.1 Introduction
Freshwater is an indispensible resource and essential for
life. Freshwater constitutes only 2.5 % of all freely available
water on earth’s surface, of which only 0.3 % is readily accessible in lakes, reservoirs and rivers (Kalff 2001). Some major
problems that humanity is facing in the twenty-first century are related to water quantity and/or water quality issues
(UNESCO 2009). The anthropogenic activities result into
large-scale contamination or pollution of water. The quality
of surface water may degrade if quantities of suspended particles, organic and inorganic substances and microorganisms
increase than their usual amounts and hence water becomes
unfit for use. "Eutrophication" is the excessive enrichment of
surface water with nutrients corresponded by high production of autotrophs, especially algae and cyanobacteria. The
high productivity leads to high respiration rates, resulting in
hypoxia or anoxia in poorly mixed waters. Low dissolved oxygen (DO) causes the loss of aquatic organism (Corell 1999).
The undesirable overgrowth of phytoplankton and their subsequent death forms a greenish slime layer over the surface
of water body, which restricts the light penetration (Khan
and Ansari 2005, Ansari et al. 2011a, b and c). The death and
decay of aquatic plants produce a foul smell and makes the
water more turbid (Beeton 2002). Lake Taihu and Lake Baiyandian of China, several Danish lakes, Greek lakes, Lake
Chapala of Mexico, Lake Yamoussoukro of West Africa, several water reservoirs and rivers in Asia, Europe, north and
south America are highly eutrophic owing to nutrient loads
from agriculture households (Jeppesen et al. 1999, Qin 1999,
Jose et al. 2000, Raja 2000, Tripathi and Adhikari 1990, Nagy
et al. 2002, Huang et al. 2003, Mama et al. 2003, Voutsa et al.
2004, Khan and Ansari 2005, Ansari et al. 2011a, b , c).
In past 30 years, seasonal variations in the characteristics
of water bodies have been studied considering a wide range
of water quality parameters. The DO in surface water layers
and biomass of aquatic macrophytes of fresh water Surinsar
Lake (Jammu, India) covaried seasonally (Sehgal and Jyoti
1987). The monsoon seasonality effectively regulated functions and processes of an artificial lentic ecosystem in Seoul
(South Korea) and had important implications to eutrophication (An 2003, An et al. 2003). The algal and phytoplankton densities were found mainly related to seasonal water
discharge in Rhine and Meuse rivers of Netherlands (Naim
1993, Ibelings et al. 1998). The seasonal variability in number and biomass of zooplanktons corresponded with O 2 availability in a polytrophic Mutek Lake, Poland (Widuto 1988).
The seasonal water quality variation in northern coast of Karawang (West Jawa) was directly related with eutrophication.
In wet season, excessive input of organic waste with high
amount of dissolved inorganic nitrogen and phosphate from
agriculture increased chlorophyll-a concentration (Sachoemar and Yanagi 1999). The nitrogen concentration in Yuqiao
reservoir basin of China declined in the average flow season
near the source and increased in rainy season (Chen et al.
2002). The seasonal changes in summer increased orthophosphate content in Tokyo Bay (Japan) and reflected variations
in biological activity (Miyata and Hattori 1986). In Austrian
part of river Danube, the seasonal patterns of nutrients were
minimum in summer and maximum in winter (Weilguni and
Humpesch 1999). The long-term studies of nutrient pattern in
Kentucky Lake (USA) revealed that the seasonal variations
in nutritional discharge were more pronounced than the actual variation in the reservoir with regulated discharge. Greater
variation in the nutrient concentrations were found on eastern
forested side of Kentucky Lake (USA) than on agriculturally
dominant embayment (Yurista et al. 2004).
Increasing inputs of inorganic fertilizers and pesticides
and inefficient use of organic wastes in agriculture adversely
affected the biophysical environment creating serious threats
to human beings (Mukhopadhyay et al. 2005). Addition of
agricultural nutrients (fertilizers) altered the nutrient cycles
of watersheds of agro-ecosystems. Nutrients enter the watersheds via precipitation, fertilizers, nitrogen fixation, irrigation, and weathering. The nutrient losses are also derived
from stream flow, subsurface flow, deep seepage, and loss
of volatile gases as well as the harvest of plants and animal
products (Kormondy 2003). Agriculture activities and livestock breeding are the two main nutrient sources responsible
for the eutrophication, besides human–urban and industrial
wastewater discharges (Sala and Mujeriego 2001).
Accelerated eutrophication of surface waters is often
caused by high phosphorus losses from agricultural fields
(Sharpley et al. 2001, Schroeder et al. 2004, Djodjic and
Bergstrom 2005, Khan and Ansari 2005, Vadas et al. 2005,
Ansari et al. 2011a, b and c). In India, the use of fertilizers
(urea, phosphate and potash) has increased manifold in the
past 40–50 years. A significant quantity of these nutrients
reaches nearby water bodies through rain water, irrigation
channels and seepage. Flood prone and rainfed water bodies
around cultivated areas often show algal blooms. In the present study the seasonal variation in the population of Lemna
minor and Spirodella polyrrhiza and water quality of the Lal
Diggi pond, close to the Aligarh Muslim University campus
has been studied at monthly interval with special reference to
variations in local meteorological variables. The duckweeds
are very sensitive to surrounding atmospheric factors. Their
potential as indicators of water quality has been studied by
several workers (Cheng et al. 2002, Khan and Ansari 2005,
Ansari and Khan 2008, 2009, Ansari et al. 2011a, b and c).
2.2 Literature Review
The domestic waste (rich in phosphate and nitrate) when
discharged in water bodies makes them highly productive
or “eutrophic”. Nutrient enrichment is the starting point of
eutrophication in any water body and is followed by uncon-
F. A. Khan et al.
2.1 Introduction
Freshwater is an indispensible resource and essential for
life. Freshwater constitutes only 2.5 % of all freely available
water on earth’s surface, of which only 0.3 % is readily accessible in lakes, reservoirs and rivers (Kalff 2001). Some major
problems that humanity is facing in the twenty-first century are related to water quantity and/or water quality issues
(UNESCO 2009). The anthropogenic activities result into
large-scale contamination or pollution of water. The quality
of surface water may degrade if quantities of suspended particles, organic and inorganic substances and microorganisms
increase than their usual amounts and hence water becomes
unfit for use. "Eutrophication" is the excessive enrichment of
surface water with nutrients corresponded by high production of autotrophs, especially algae and cyanobacteria. The
high productivity leads to high respiration rates, resulting in
hypoxia or anoxia in poorly mixed waters. Low dissolved oxygen (DO) causes the loss of aquatic organism (Corell 1999).
The undesirable overgrowth of phytoplankton and their subsequent death forms a greenish slime layer over the surface
of water body, which restricts the light penetration (Khan
and Ansari 2005, Ansari et al. 2011a, b and c). The death and
decay of aquatic plants produce a foul smell and makes the
water more turbid (Beeton 2002). Lake Taihu and Lake Baiyandian of China, several Danish lakes, Greek lakes, Lake
Chapala of Mexico, Lake Yamoussoukro of West Africa, several water reservoirs and rivers in Asia, Europe, north and
south America are highly eutrophic owing to nutrient loads
from agriculture households (Jeppesen et al. 1999, Qin 1999,
Jose et al. 2000, Raja 2000, Tripathi and Adhikari 1990, Nagy
et al. 2002, Huang et al. 2003, Mama et al. 2003, Voutsa et al.
2004, Khan and Ansari 2005, Ansari et al. 2011a, b , c).
In past 30 years, seasonal variations in the characteristics
of water bodies have been studied considering a wide range
of water quality parameters. The DO in surface water layers
and biomass of aquatic macrophytes of fresh water Surinsar
Lake (Jammu, India) covaried seasonally (Sehgal and Jyoti
1987). The monsoon seasonality effectively regulated functions and processes of an artificial lentic ecosystem in Seoul
(South Korea) and had important implications to eutrophication (An 2003, An et al. 2003). The algal and phytoplankton densities were found mainly related to seasonal water
discharge in Rhine and Meuse rivers of Netherlands (Naim
1993, Ibelings et al. 1998). The seasonal variability in number and biomass of zooplanktons corresponded with O 2 availability in a polytrophic Mutek Lake, Poland (Widuto 1988).
The seasonal water quality variation in northern coast of Karawang (West Jawa) was directly related with eutrophication.
In wet season, excessive input of organic waste with high
amount of dissolved inorganic nitrogen and phosphate from
agriculture increased chlorophyll-a concentration (Sachoemar and Yanagi 1999). The nitrogen concentration in Yuqiao
reservoir basin of China declined in the average flow season
near the source and increased in rainy season (Chen et al.
2002). The seasonal changes in summer increased orthophosphate content in Tokyo Bay (Japan) and reflected variations
in biological activity (Miyata and Hattori 1986). In Austrian
part of river Danube, the seasonal patterns of nutrients were
minimum in summer and maximum in winter (Weilguni and
Humpesch 1999). The long-term studies of nutrient pattern in
Kentucky Lake (USA) revealed that the seasonal variations
in nutritional discharge were more pronounced than the actual variation in the reservoir with regulated discharge. Greater
variation in the nutrient concentrations were found on eastern
forested side of Kentucky Lake (USA) than on agriculturally
dominant embayment (Yurista et al. 2004).
Increasing inputs of inorganic fertilizers and pesticides
and inefficient use of organic wastes in agriculture adversely
affected the biophysical environment creating serious threats
to human beings (Mukhopadhyay et al. 2005). Addition of
agricultural nutrients (fertilizers) altered the nutrient cycles
of watersheds of agro-ecosystems. Nutrients enter the watersheds via precipitation, fertilizers, nitrogen fixation, irrigation, and weathering. The nutrient losses are also derived
from stream flow, subsurface flow, deep seepage, and loss
of volatile gases as well as the harvest of plants and animal
products (Kormondy 2003). Agriculture activities and livestock breeding are the two main nutrient sources responsible
for the eutrophication, besides human–urban and industrial
wastewater discharges (Sala and Mujeriego 2001).
Accelerated eutrophication of surface waters is often
caused by high phosphorus losses from agricultural fields
(Sharpley et al. 2001, Schroeder et al. 2004, Djodjic and
Bergstrom 2005, Khan and Ansari 2005, Vadas et al. 2005,
Ansari et al. 2011a, b and c). In India, the use of fertilizers
(urea, phosphate and potash) has increased manifold in the
past 40–50 years. A significant quantity of these nutrients
reaches nearby water bodies through rain water, irrigation
channels and seepage. Flood prone and rainfed water bodies
around cultivated areas often show algal blooms. In the present study the seasonal variation in the population of Lemna
minor and Spirodella polyrrhiza and water quality of the Lal
Diggi pond, close to the Aligarh Muslim University campus
has been studied at monthly interval with special reference to
variations in local meteorological variables. The duckweeds
are very sensitive to surrounding atmospheric factors. Their
potential as indicators of water quality has been studied by
several workers (Cheng et al. 2002, Khan and Ansari 2005,
Ansari and Khan 2008, 2009, Ansari et al. 2011a, b and c).
2.2 Literature Review
The domestic waste (rich in phosphate and nitrate) when
discharged in water bodies makes them highly productive
or “eutrophic”. Nutrient enrichment is the starting point of
eutrophication in any water body and is followed by uncon-