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Analysing lakes

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Prof. A.Balasubramanian
Prof. A.Balasubramanian

Analyzing a lake ecosystem is an interesting and everlasting area of Environmental Studies. Since these water bodies are subjected to pollution and degradation, analyzing them is an essential requirement. These analytical works come under a special branch of Science called Limnology.

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BY PROF. A. BALASUBRAMANIAN Centre for Advanced Studies in Earth Science University of Mysore, India
•large in-land bodies of fresh or salt water •good aquatic ecosystems providing a lot of benefits to human beings and to animal life •slow-moving or standing water bodies with good water resource and biodiversity • used as water sources for drinking, domestic utilization , irrigation and recreation
•A lake moderates the surrounding region’s temperature and climate and thereby attracting people to settle around. •Many lakes are used for developing fisheries and aquaculture. •City dwellers establish pathways around a lake. These tracks help them to walk around every day. •Boating is a good recreational activity for children and adults in a lake.
•People cut the aquatic plants and supply them as fodder to cattle and also use them for general purposes. •The flowers of lake vegetation are unique collections for selling and decorations. •Many towns and municipalities survive only with lake water as their primary source of drinking water to the entire population.
•Analyzing a lake ecosystem is an interesting and everlasting area of Environmental Studies •Since these water bodies are subjected to pollution and degradation, analyzing them is an essential requirement •These analytical works come under a special branch of Science called Limnology
Limnology is the scientific study of inland water bodies. It may be a pond, lake, river, estuary with fresh or saline waters. It is a unique branch comprising many interdisciplinary subjects like Geology, Hydrology, Meteorology , Botany, Zoology, Physics, Chemistry, Ecology, Environmental Science, Fishery Biology, Civil Engineering, Environmental Engineering and Pollution Control.
Since lakes are aquatic ecosystems with various biotic and a biotic factors, Limnological Research involves an interdisciplinary analysis. The methodology of research in limnology may be the same but the application area may be different like a lake or a river or an estuary. Each one of these have their own uniqueness in water quantity, quality, fauna, flora and dynamism. Sometimes, inland seas are considered for limnological studies.
•Lakes are extremely varied in terms of origin, occurrence, size, shape, depth, water chemistry, and other features. •They are dynamic ecosystems. •Most of them are under the direct or indirect influences of human activities and development. •A lot of factors lead to the deterioration of lakes and their survival.
•Protection of a lake from pollution or degradation is a major aspect of development. •Intelligent utilization of a lake’s all natural resources requires a detailed analysis. •In this module, let us see the factors which are very essential while analysing a lake as an ecosystem.
1. GEOGRAPHIC SETTING 2. MORPHOMETRY OF A LAKE 3. WATERSHED CHARACTERISTICS 4. CLIMATOLOGY 5. HYDROLOGY 6. HYDROCHEMISTRY 7. ENVIRONMENTAL BIOLOGY 8. SEDIMENTOLOGY 9. MICROBIOLOGY 10. POLLUTION AND POLLUTANTS 11. TROPHIC STATE & EUTROPHICATION 12. RESTORATION.
The location of a lake and its geographic setting are to be understood first. Its Boundary , latitude, longitude and altitude. Origin of the lake- Natural (Glacial/Tectonic/ Volcanic/ erosional ); Artificial ( Reservoirs, waterworks) Ownership - National/ State ; Riparian jurisdictions Demographic conditions
•Lakes are characterized by their basin morphometry which is the actual depression holding the water and its physiography. •This analysis involves the measurement of surface area , Depth and thickness of water column and volume of lake water available in storage, the shorelines, their shape and areal extent . •Bathymetric charts are prepared for this purpose.
•Every lake belongs to a watershed with its own isolated or regional catchment area. •This includes the topography, drainage network and other surface water resources which have direct or indirect influence. •Landuse- agriculture, urbanization, industrialization, lawns, parks, infrastructural development. •Landcover – vegetation and forest cover, soils, grassland, marshy land, wasteland, rangeland, •Major Geological features- Rock types – Distribution. •Structures like Faults , Lineaments and joints. •Dykes and surface exposures.
•Lakes are mainly influenced by the regional or local climate and weather systems. •Since climate has a direct role in most of the processes that happen in a lake, meteorological parameters are to be analysed thoroughly. •Daily variation in Temperature, Sun shine hours , rainfall, Evapotranspiration, humidity in air, wind velocity and direction, atmospheric pressure , evaporation and interception.
•The quantity of water existing within a lake and the inflow- outflow volumes are very essential in understanding the dynamics of a lake. •These depends on the basin size, rainfall pattern, runoff components, soils profile, infiltration of soils, evapotranspiration, diversions, and recharge into groundwater systems. •Water balance of a lake with reference to time is a basic requirement. •The relationship between rainfall, inflow-outflow, consumption by various organisms and processes are also related to lake water levels. •The chemistry of lake water is also controlled by the quantity of inflow and pollutant load carried by it.
•The quality of water in a lake is determined by its • Physical Properties • Chemical composition • Biological Properties and • Pollutant characteristics. •Without analysing these properties, research on lake as ecosystems may have little significance.
•Surface water temperature, color, odour •Thermal stratification with depth. •Light penetration •Turbidity •Transparency level using Secchi disks at all locations.
•Electrical conductivity, Total Dissolved Solids •pH •Oxidation-Reduction Potential •Major Cations- Calcium, Magnesium, Sodium, Potassium •Major Anions- Bicarbonate, Carbonate , Chloride, Sulphate, Fluoride. •Trace Elements- Iron, Aluminum, Copper, Nickel, Cadmium, Chromium, Lead, Zinc, Mercury, Arsenic, and Cobalt. •Nutrients- Nitrates & Phosphate. •Ammonical Nitrogen.
•Dissolved Oxygen •Biochemical Oxygen Demand •Chemical Oxygen Demand •Volatile Organic Carbon •Total Coliform •Feacal Coliform
•Phytoplankton, Zooplankton •Benthic fauna and flora, Nektons •Macrophytes, Biomass, Productivity •Emergent vegetation, invasive plants •Species density and composition •Biodiversity , Fish species •Birds , fouls and other animals. •Uptake of nutrients by plants and animals •Growth rates, excretion rates, mortality rates and settling rates.
•Lake sediments are called as lacustrine deposits. •Inflowing water carries a lot of sediments into a lake. •Pollutants and nutrients may travel through inflow. •Suspended and bed load sediments may enter into a lake during every season of rainfall.
•Urban sewage water may also add to these volumes. •Chemistry of sediments are to be analysed with reference to their major ions, trace metals and nutrients •Data of Daily , monthly and annual sediment loads are essential while analysing the lake dynamics. •Rate of siltation and their impact on the volume of water storage.
•The material at the bottom of a lake, or lake bed, may be composed of a wide variety of inorganics, such as silt or sand, and organic material, such as decaying plant or animal matter. •The composition of the lake bed has a significant impact on the flora and fauna found within the lake's environs by contributing to the amounts and the types of nutrients available.
Diatoms, algae, fungi Bacteria,- pathogenic and non-pathogenic Solmonella Microbial mobility Decaying rates
Domestic pollution- pollutants Municipal Sewage water inflow Urban storm drainage water inflow Industrial sewage or effluent, if any Agricultural runoff Agrochemical inputs Cleaning of automobiles Oil spills from boating operations Other human disturbances.
•The trophic state of a lake is determined based on various physico-chemical parameters which we have seen just now. •The quantities of nitrogen, phosphorus, and other biologically useful nutrients are the primary determinants of a lake's trophic state index (TSI). •Nutrients tend to be the limiting resources in standing water bodies, so increased concentrations will result in the increased plant growth, followed by corollary increases in subsequent trophic levels. •Consequently, a lake's trophic index may sometimes be used to make a rough estimate of its biological condition.
Lakes can be also categorized on the basis of their richness in nutrients, which typically affect their plant growth. Nutrient-poor lakes are said to be oligotrophic lakes and are generally clear, having a low concentration of plant life. Mesotrophic lakes have good clarity and contain an average level of nutrients. Eutrophic lakes are fully enriched with nutrients, resulting in good plant growth and possible algal blooms. This itself may affect the life of the lake.
•Hypertrophic lakes are bodies of water that have been excessively enriched with nutrients. •These lakes typically have poor clarity and are subject to devastating algal blooms. •Lakes typically reach this condition due to human activities, such as heavy use of fertilizers in the lake catchment area. •Such lakes are of little use to humans and have a poor ecosystem due to decreased dissolved oxygen.
It is necessary to protect the life of every lake. Lakes need continuous monitoring and protection. Once the ecosystem is disturbed then restoration becomes a tedious and expensive affair. Silt control, weed control, pollutant load control, aeration and inflow management are essential steps.
•It is our duty to conserve and preserve the natural resources. •Detailed analysis of the ecology of such natural resources will alone help us to understand and go for proper management methods. •Analysing lakes will be an interesting research area for all geographers, geologists, environmentalists, biologist, chemists, experts in physics, biochemistry, naturalists, engineers , economists, taxonomists, and town planners. •The preliminary methods have alone been seen now. •Further information is also available for researchers in various forms.
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More Related Content

Analysing lakes

  • 1. BY PROF. A. BALASUBRAMANIAN Centre for Advanced Studies in Earth Science University of Mysore, India
  • 2. •large in-land bodies of fresh or salt water •good aquatic ecosystems providing a lot of benefits to human beings and to animal life •slow-moving or standing water bodies with good water resource and biodiversity • used as water sources for drinking, domestic utilization , irrigation and recreation
  • 3. •A lake moderates the surrounding region’s temperature and climate and thereby attracting people to settle around. •Many lakes are used for developing fisheries and aquaculture. •City dwellers establish pathways around a lake. These tracks help them to walk around every day. •Boating is a good recreational activity for children and adults in a lake.
  • 4. •People cut the aquatic plants and supply them as fodder to cattle and also use them for general purposes. •The flowers of lake vegetation are unique collections for selling and decorations. •Many towns and municipalities survive only with lake water as their primary source of drinking water to the entire population.
  • 5. •Analyzing a lake ecosystem is an interesting and everlasting area of Environmental Studies •Since these water bodies are subjected to pollution and degradation, analyzing them is an essential requirement •These analytical works come under a special branch of Science called Limnology
  • 6. Limnology is the scientific study of inland water bodies. It may be a pond, lake, river, estuary with fresh or saline waters. It is a unique branch comprising many interdisciplinary subjects like Geology, Hydrology, Meteorology , Botany, Zoology, Physics, Chemistry, Ecology, Environmental Science, Fishery Biology, Civil Engineering, Environmental Engineering and Pollution Control.
  • 7. Since lakes are aquatic ecosystems with various biotic and a biotic factors, Limnological Research involves an interdisciplinary analysis. The methodology of research in limnology may be the same but the application area may be different like a lake or a river or an estuary. Each one of these have their own uniqueness in water quantity, quality, fauna, flora and dynamism. Sometimes, inland seas are considered for limnological studies.
  • 8. •Lakes are extremely varied in terms of origin, occurrence, size, shape, depth, water chemistry, and other features. •They are dynamic ecosystems. •Most of them are under the direct or indirect influences of human activities and development. •A lot of factors lead to the deterioration of lakes and their survival.
  • 9. •Protection of a lake from pollution or degradation is a major aspect of development. •Intelligent utilization of a lake’s all natural resources requires a detailed analysis. •In this module, let us see the factors which are very essential while analysing a lake as an ecosystem.
  • 10. 1. GEOGRAPHIC SETTING 2. MORPHOMETRY OF A LAKE 3. WATERSHED CHARACTERISTICS 4. CLIMATOLOGY 5. HYDROLOGY 6. HYDROCHEMISTRY 7. ENVIRONMENTAL BIOLOGY 8. SEDIMENTOLOGY 9. MICROBIOLOGY 10. POLLUTION AND POLLUTANTS 11. TROPHIC STATE & EUTROPHICATION 12. RESTORATION.
  • 11. The location of a lake and its geographic setting are to be understood first. Its Boundary , latitude, longitude and altitude. Origin of the lake- Natural (Glacial/Tectonic/ Volcanic/ erosional ); Artificial ( Reservoirs, waterworks) Ownership - National/ State ; Riparian jurisdictions Demographic conditions
  • 12. •Lakes are characterized by their basin morphometry which is the actual depression holding the water and its physiography. •This analysis involves the measurement of surface area , Depth and thickness of water column and volume of lake water available in storage, the shorelines, their shape and areal extent . •Bathymetric charts are prepared for this purpose.
  • 13. •Every lake belongs to a watershed with its own isolated or regional catchment area. •This includes the topography, drainage network and other surface water resources which have direct or indirect influence. •Landuse- agriculture, urbanization, industrialization, lawns, parks, infrastructural development. •Landcover – vegetation and forest cover, soils, grassland, marshy land, wasteland, rangeland, •Major Geological features- Rock types – Distribution. •Structures like Faults , Lineaments and joints. •Dykes and surface exposures.
  • 14. •Lakes are mainly influenced by the regional or local climate and weather systems. •Since climate has a direct role in most of the processes that happen in a lake, meteorological parameters are to be analysed thoroughly. •Daily variation in Temperature, Sun shine hours , rainfall, Evapotranspiration, humidity in air, wind velocity and direction, atmospheric pressure , evaporation and interception.
  • 15. •The quantity of water existing within a lake and the inflow- outflow volumes are very essential in understanding the dynamics of a lake. •These depends on the basin size, rainfall pattern, runoff components, soils profile, infiltration of soils, evapotranspiration, diversions, and recharge into groundwater systems. •Water balance of a lake with reference to time is a basic requirement. •The relationship between rainfall, inflow-outflow, consumption by various organisms and processes are also related to lake water levels. •The chemistry of lake water is also controlled by the quantity of inflow and pollutant load carried by it.
  • 16. •The quality of water in a lake is determined by its • Physical Properties • Chemical composition • Biological Properties and • Pollutant characteristics. •Without analysing these properties, research on lake as ecosystems may have little significance.
  • 17. •Surface water temperature, color, odour •Thermal stratification with depth. •Light penetration •Turbidity •Transparency level using Secchi disks at all locations.
  • 18. •Electrical conductivity, Total Dissolved Solids •pH •Oxidation-Reduction Potential •Major Cations- Calcium, Magnesium, Sodium, Potassium •Major Anions- Bicarbonate, Carbonate , Chloride, Sulphate, Fluoride. •Trace Elements- Iron, Aluminum, Copper, Nickel, Cadmium, Chromium, Lead, Zinc, Mercury, Arsenic, and Cobalt. •Nutrients- Nitrates & Phosphate. •Ammonical Nitrogen.
  • 19. •Dissolved Oxygen •Biochemical Oxygen Demand •Chemical Oxygen Demand •Volatile Organic Carbon •Total Coliform •Feacal Coliform
  • 20. •Phytoplankton, Zooplankton •Benthic fauna and flora, Nektons •Macrophytes, Biomass, Productivity •Emergent vegetation, invasive plants •Species density and composition •Biodiversity , Fish species •Birds , fouls and other animals. •Uptake of nutrients by plants and animals •Growth rates, excretion rates, mortality rates and settling rates.
  • 21. •Lake sediments are called as lacustrine deposits. •Inflowing water carries a lot of sediments into a lake. •Pollutants and nutrients may travel through inflow. •Suspended and bed load sediments may enter into a lake during every season of rainfall.
  • 22. •Urban sewage water may also add to these volumes. •Chemistry of sediments are to be analysed with reference to their major ions, trace metals and nutrients •Data of Daily , monthly and annual sediment loads are essential while analysing the lake dynamics. •Rate of siltation and their impact on the volume of water storage.
  • 23. •The material at the bottom of a lake, or lake bed, may be composed of a wide variety of inorganics, such as silt or sand, and organic material, such as decaying plant or animal matter. •The composition of the lake bed has a significant impact on the flora and fauna found within the lake's environs by contributing to the amounts and the types of nutrients available.
  • 24. Diatoms, algae, fungi Bacteria,- pathogenic and non-pathogenic Solmonella Microbial mobility Decaying rates
  • 25. Domestic pollution- pollutants Municipal Sewage water inflow Urban storm drainage water inflow Industrial sewage or effluent, if any Agricultural runoff Agrochemical inputs Cleaning of automobiles Oil spills from boating operations Other human disturbances.
  • 26. •The trophic state of a lake is determined based on various physico-chemical parameters which we have seen just now. •The quantities of nitrogen, phosphorus, and other biologically useful nutrients are the primary determinants of a lake's trophic state index (TSI). •Nutrients tend to be the limiting resources in standing water bodies, so increased concentrations will result in the increased plant growth, followed by corollary increases in subsequent trophic levels. •Consequently, a lake's trophic index may sometimes be used to make a rough estimate of its biological condition.
  • 27. Lakes can be also categorized on the basis of their richness in nutrients, which typically affect their plant growth. Nutrient-poor lakes are said to be oligotrophic lakes and are generally clear, having a low concentration of plant life. Mesotrophic lakes have good clarity and contain an average level of nutrients. Eutrophic lakes are fully enriched with nutrients, resulting in good plant growth and possible algal blooms. This itself may affect the life of the lake.
  • 28. •Hypertrophic lakes are bodies of water that have been excessively enriched with nutrients. •These lakes typically have poor clarity and are subject to devastating algal blooms. •Lakes typically reach this condition due to human activities, such as heavy use of fertilizers in the lake catchment area. •Such lakes are of little use to humans and have a poor ecosystem due to decreased dissolved oxygen.
  • 29. It is necessary to protect the life of every lake. Lakes need continuous monitoring and protection. Once the ecosystem is disturbed then restoration becomes a tedious and expensive affair. Silt control, weed control, pollutant load control, aeration and inflow management are essential steps.
  • 30. •It is our duty to conserve and preserve the natural resources. •Detailed analysis of the ecology of such natural resources will alone help us to understand and go for proper management methods. •Analysing lakes will be an interesting research area for all geographers, geologists, environmentalists, biologist, chemists, experts in physics, biochemistry, naturalists, engineers , economists, taxonomists, and town planners. •The preliminary methods have alone been seen now. •Further information is also available for researchers in various forms.