DOCSLIB.ORG

An Introduction to the Processes, Problems, and Management of Urban Lakes

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
An Introduction to the Processes, Problems, and Management of Urban Lakes GEOLOGICAL SURVEY CIRCULAR 601-K An Introduction to the Processes, Problems, and Management of Urban Lakes An Introduction to the Processes, Problems, and Management of Urban Lakes By L. J. Britton, R. C. Averett, and R. F. Ferreira WATER IN THE URBAN ENVIRONMENT G E 0 l 0 G I C A l S U R V E Y C I R C U l A R 601-K 1975 United States Department of the Interior ROGERS C. B. MORTON, Secretary Geological Survey V. E. McKelvey, Director First printing 1975 Second printing 19 77 Free on application to U.S. Geological Survey, National Center, Reston, Va 22092 CONTENTS Page Page Glossary of selected terms ....................... IV Planning and management of watersheds and lakes Conversion factors ............................. VI for water quality control--Continued Abstract ..................................... 1 Watershed management . 13 Man and his lakes .............................. 1 Lake management . 13 What this report is all about ...................... 2 Water quality control . 13 Physics, chemistry, and biology of lakes ............ 2 Algal blooms . 13 Physical characteristics ..................... 2 Light penetration ...................... 2 Anaerobic conditions . 14 Temperature ......................... 3 Fish kills . 15 Suspended sediment ................... 5 Sediment deposition . 15 Morphology .......................... 5 Summary of management options . 15 Chemical characteristics ..................... 5 Conducting lake studies . 15 Major chemical constituents ............. 5 Measuring the properties of lakes . 16 Minor chemical constituents ............. 5 Physical measurements . 16 Major plant nutrients ................... 6 Mapping.......................... 16 Dissolved gases ........................ 6 Temperature . 16 Biological characteristics .................... 6 Light penetration . 17 Plankton ............................ 6 Chemical measurements . 17 Benthos ............................. 6 Dissolved oxygen . 17 Nekton ............................. 6 Alkalinity and pH . 17 Processes in lakes .............................. 9 Major chemical constituents and Photosynthesis and respiration ............... 9 specific conductance . 17 Eutrophication ........................... 10 Minor chemical constituents . 18 The biogeochemical cycle ................... 10 Major plant nutrients . 18 Sedimentation ........................ 11 Biological measurements . 19 Nutrient cycling ....................... 11 Phytoplankton and periphyton . 19 Planning and management of watersheds and lakes Zooplankton . 20 for water quality control ...................... 12 Benthic invertebrates . 20 Lake basin planning ........................ 12 References cited . 21 ILLUSTRATIONS Page Figure 1. The major life zones of a lake . 3 2. Seasonal thermal profiles of a warm monomictic lake . 4 3. Representative lake organisms . 9 4. Effect of man upon the eutrophication of lakes . 11 5. Sources and cycling of elements in a lake . 12 6. Typical growth pattern of blooming unicellular algae . 14 TABLE Page Table 1. Common forms, minimum requirements, and some sources of elements essential for the growth of algae 7 III GLOSSARY OF SELECTED TERMS [Many of the definitions in this glossary were obtained or modified from Slack and others (1973).] Absorption (n). To take up and incorporate within the Consumer (n). An organism that is unable to manufac­ body. ture its food from nonliving matter and is dependent Adsorption (n). To take up and hold by adhesion to the on the energy and materials stored in other living surface. things. Aerate (v), aerator (n). To charge or treat with air or Decomposition, decomposer (n). The breakdown of other gases, usually with oxygen. dead plant and animal tissue by bacteria to the Aerobic (adj). Having oxygen. elemental state. Alga, algae (n), algal (adj). A group of simple primitive Density (n). The quantity or mass of a substance per plants that live in wet or damp places, and generally unit volume. Computed as grams per cubic centi­ are microscopic in size, containing chlorophyll and metre, in the case of water. lacking roots, stems, and leaves. Detritus (n). Fragmented material of inorganic or Algal bloom (n). A high concentration of a particular organic origin. algal species, amounting to ~ million to I million Diatom (n). A unicellular or colonial alga having a cells per litre of water or more. siliceous shell. Algicide ( n). A chemical that kills algae. Dinoflagellate (n). A typically yellow-brown unicellular Anaerobic {adj). Devoid of oxygen. alga that swims by means of two laterally attached Assimilation (n), assimilate (v). To take up or incor­ appendages called flagella (fig. 3). Dystrophic (adj). Brown-water lakes with a very low porate within the body. Technically, secondary pro­ lime content and a very high humus content, often ductivity plus respiration and other losses. characterized by a severe lack of nutrients (Ruttner, Autumn overturn (n). The mixing of the entire water 1963, p. 254). mass of a lake in the autumn. Ecosystem (n). The community of plants and animals Bacterium, bacteria (n), bacterial {adj). Microscopic interacting together with the physical and chemical unicellular organisms. Some bacteria cause disease environment. while others perform an essential role in the recycling Emersed plant (n). A rooted aquatic plant with leaves or of materials. other structures extending above the water surface Benthos, benthic zone (n). Organisms living in or on the (sometimes called emergent plant). bottom of an aquatic environment. The bottom of a Enrichment (n). Addition or accumulation of plant lake or stream. nutrients within a body of water (Greeson, 1971, Biochemical oxygen demand (BOD) (n). The quantity of P• 139). 1 Environment (n). The sum of all the external physical, dissolved oxygen, in milligrams per litre, used for the chemical, and biological conditions and influences decomposition of organic material by microorga­ that affect the life and development of an organism. nisms, such as bacteria. Epilimnion (n), epilimnetic (adj). The upper, relatively Biomass (n). The amount of living matter present in a warm, circulating zone of water in a thermally unit area or volume, at any given time. stratified lake. Biota (n), biotic (adj). All the plants and animals in a Erosion (n). The general process or group of processes particular area. whereby the materials of the Earth's crust are Blue-green algae (n). A group of algae with a blue loosened, dissolved, or worn away, and removed from pigment, in addition to the green chlorophyll. Blue­ one place to another by weathering, solution, cor­ green algae group usually causes nuisance conditions rasion, and transportation (Gary and others, 1972). in water. Euphotic zone (n). That part of the aquatic environment Carbohydrate (n). Chemical compounds containing car­ where light penetration is sufficient for photosyn­ bon, hydrogen, and oxygen, such as sugars, starches, thesis. Refers to the combined littoral and limnetic or celluloses. Most are formed by green plants and zones of lakes. serve as basic food units for animals. Eutrophication (n), euthrophic (adj). The natural Compensation level or depth (n). The depth of water at process of enrichment and aging of a body of water which oxygen production by photosynthesis balances that may be accelerated by the activities of man. oxygen uptake by respiration of plants and animals. Pertains to water bodies in which primary production The depth is usually where light intensity is reduced is high because of a large supply of available to about 1 percent of the surface light (Odum, 1971, nutrients. (See also Dystrophic, Mesotrophic, and p. 301). Oligotrophic.) IV Fauna (n), faunal (adj). A collective term for all the Monitoring (n). A type of sampling program designed to types of animals in an area. determine time-trend changes. Food chain (n). The transfer of food energy and Monomictic ( adj). Lakes having only one circulation materials from plants through other organisms, with period per year. repeated eating and being eaten. Nekton (n). Actively swimming aquatic organisms, such Fungus, fungi (n). Plants lacking chlorophyll, including as fish. molds, yeasts, mildews, rusts, and mushrooms. Nutrient (n). Any chemical element, ion, or compound Grab (n). An instrument designed to "bite" into the that is required by an organism for the continuation bottom sediment of a lake or stream to sample the of growth, reproduction, and other life processes. bottom materials and the benthos. Nymph (n), nymphal (adj). An immature stage of an Green algae ( n). Algae that have pigments similar in insect in which the body form resembles the adult. color to those of higher green plants. Some forms (See also Larva.) produce algal mats or floating "moss" in lakes. Oligotrophic (adj). Pertaining to waters in which primary Heterotroph (n), heterotrophic (adj). An organism that production is low as a consequence of a small supply requires organic material as a source of nutrition; of available nutrients. includes all animals and most bacteria. Organic (n). Pertaining or relating to a compound Homothermous ( adj). At the same temperature through­ containing carbon. out. Oxidation (n). The process in which oxygen chemically Hypolimnion (n), hypolimnetic (adj). The lower, rela­ combines with a substance, or in which an element tively cold, non-circulating water zone in a thermally loses electrons. stratified lake. Periphyton (n), periphytic (adj). The community of Interpretative (adj). A type of sampling program or microorganisms, such
Load more

Recommended publications
  • Pond and Lake Ecosystems a Pond Or Lake Ecosystem Includes Biotic
    Pond and Lake Ecosystems A pond or lake ecosystem includes biotic (living) plants, animals and micro-organisms, as well as abiotic (nonliving) physical and chemical interactions. Pond and lake ecosystems are a prime example of lentic ecosystems. Lentic refers to stationary or relatively still water, from the Latin lentus, which means sluggish. A typical lake has distinct zones of biological communities linked to the physical structure of the lake. (Figure below) The littoral zone is the near shore area where sunlight penetrates all the way to the sediment and allows aquatic plants (macrophytes) to grow. Light levels of about 1% or less of surface values usually define this depth. The 1% light level also defines the euphotic zone of the lake, which is the layer from the surface down to the depth where light levels become too low for photosynthesizers. In most lakes, the sunlit euphotic zone occurs within the epilimnion. However, in unusually transparent lakes, photosynthesis may occur well below the thermocline into the perennially cold hypolimnion. For example, in western Lake Superior near Duluth, MN, summertime algal photosynthesis and growth can persist to depths of at least 25 meters, while the mixed layer, or epilimnion, only extends down to about 10 meters. Ultra-oligotrophic Lake Tahoe, CA/NV, is so transparent that algal growth historically extended to over 100 meters, though its mixed layer only extends to about 10 meters in summer. Unfortunately, inadequate management of the Lake Tahoe basin since about 1960 has led to a significant loss of transparency due to increased algal growth and increased sediment inputs from stream and shoreline erosion.
    [Show full text]
  • Lake Ecology
    Fundamentals of Limnology Oxygen, Temperature and Lake Stratification Prereqs: Students should have reviewed the importance of Oxygen and Carbon Dioxide in Aquatic Systems Students should have reviewed the video tape on the calibration and use of a YSI oxygen meter. Students should have a basic knowledge of pH and how to use a pH meter. Safety: This module includes field work in boats on Raystown Lake. On average, there is a death due to drowning on Raystown Lake every two years due to careless boating activities. You will very strongly decrease the risk of accident when you obey the following rules: 1. All participants in this field exercise will wear Coast Guard certified PFDs. (No exceptions for teachers or staff). 2. There is no "horseplay" allowed on boats. This includes throwing objects, splashing others, rocking boats, erratic operation of boats or unnecessary navigational detours. 3. Obey all boating regulations, especially, no wake zone markers 4. No swimming from boats 5. Keep all hands and sampling equipment inside of boats while the boats are moving. 6. Whenever possible, hold sampling equipment inside of the boats rather than over the water. We have no desire to donate sampling gear to the bottom of the lake. 7. The program director has final say as to what is and is not appropriate safety behavior. Failure to comply with the safety guidelines and the program director's requests will result in expulsion from the program and loss of Field Station privileges. I. Introduction to Aquatic Environments Water covers 75% of the Earth's surface. We divide that water into three types based on the salinity, the concentration of dissolved salts in the water.
    [Show full text]
  • Freshwater Ecosystem: Part 2
    Paper : 12 Principles of Ecology Module : 22 Types of Ecosystems: Aquatic Ecosystem-Fresh Water Ecosystem: Part 2 Development Team Principal Investigator : Prof. Neeta Sehgal Department of Zoology, University of Delhi Co-Principal Investigator : Prof. D.K. Singh Department of Zoology, University of Delhi Paper Coordinator : Prof. D.K. Singh Department of Zoology, University of Delhi Content Writer : Dr. Sushma Bhardwaj , Deshbandhu College, DU Ms. Harshita Mishra, Research Scholar, DU Content Reviewer : Prof. K.S. Rao Department of Botany, University of Delhi 1 Principles of Ecology ZOOLOGY Aquatic Ecosystem: Freshwater Ecosystem: Part 2 Description of Module Subject Name ZOOLOGY Paper Name Zool 12 Principles of Ecology Module Name/Title Types of Ecosystems: Aquatic Ecosystem Module Id M22: Aquatic Ecosystem: Freshwater Ecosystem: Part 2 Keywords Lentic, lotic, community, lake, temperate lake, zone, eutrophy, Langmuir circulation Contents 1. Learning Objectives 2. Introduction 3. The Lentic Aquatic System 3.1. Zonation in Lentic Systems 3.2. Characteristics of Lentic Ecosystem 3.3. Lentic Community 3.3.1. Communities of the littoral zone 3.3.2. Communities of Limnetic Zone 3.3.3. Communities of Profundal Zone 4. Lake Ecosystem 4.1. Thermal Properties of Lake 4.2. Seasonal Cycle in Temperate Lakes 4.3. Biological Oxygen Demand 4.4. Eutrophy and Oligotrophy 4.5. Langmuir Circulation and the Descent of the Thermocline 4.6. Types of Lakes 5. State of Freshwater Ecosystems in Present Scenario 5.1. Causes of Change in the properties of freshwater bodies 5.1.1. Climate Change 5.1.2. Change in Water Flow 5.1.3. Land-Use Change 5.1.4.
    [Show full text]
  • Comparison of Littoral and Limnetic Zooplankton Communities of Lake Mead
    Publications (WR) Water Resources 5-1987 Comparison of littoral and limnetic zooplankton communities of Lake Mead Patrick Joseph Sollberger University of Nevada, Las Vegas Follow this and additional works at: https://digitalscholarship.unlv.edu/water_pubs Part of the Biology Commons, Environmental Indicators and Impact Assessment Commons, Environmental Monitoring Commons, Fresh Water Studies Commons, Natural Resources and Conservation Commons, Terrestrial and Aquatic Ecology Commons, and the Water Resource Management Commons Repository Citation Sollberger, P. J. (1987). Comparison of littoral and limnetic zooplankton communities of Lake Mead. Available at: https://digitalscholarship.unlv.edu/water_pubs/84 This Thesis is protected by copyright and/or related rights. It has been brought to you by Digital Scholarship@UNLV with permission from the rights-holder(s). You are free to use this Thesis in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s) directly, unless additional rights are indicated by a Creative Commons license in the record and/ or on the work itself. This Thesis has been accepted for inclusion in Publications (WR) by an authorized administrator of Digital Scholarship@UNLV. For more information, please contact [email protected]. QL. Comparison of Littoral and Limnetic Zooplankton Communities of Lake Mead by x Patrick Joseph Sollberger A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Biological Sciences Department of Biological Sciences University of Nevada, Las Vegas May, 1987 UNIVERSITY OF NEVADA, LAS VEGAS LIBRARY thesis of Patrick Joseph Sollberger for the degree of tester of Science in the Biological Sciences is approved.
    [Show full text]
  • Aquatic Ecosystem Part 1 a SHORT NOTE for B.SC ZOOLOGY
    2020 Aquatic ecosystem part 1 A SHORT NOTE FOR B.SC ZOOLOGY WRITTEN BY DR.MOTI LAL GUPTA ,H.O.D ,DEPARTMENT OF ZOOLOGY,B.N.COLLEGE,PATNA UNIVERSITY [Type the author name] DEPARTMENT OF ZOOLOGY,B.N COLLEGE, P.U 4/16/2020 Aquatic ecosystem part 1 2 1 Department of zoology,B.N College,P.U Page 2 Aquatic ecosystem part 1 3 Contents 1. Learning Objectives 2. Introduction 3. The Lentic Aquatic System Zonation in Lentic Systems Characteristics of Lentic Ecosystem Lentic Community Communities of the littoral zone Communities of Limnetic Zone Communities of Profundal Zone 4. Lake Ecosystem Thermal Properties of Lake Seasonal Cycle in Temperate Lakes Biological Oxygen Demand Eutrophy and Oligotrophy Langmuir Circulation and the Descent of the Thermocline Types of Lakes 5. State of Freshwater Ecosystems in Present Scenario Causes of Change in the properties of freshwater bodies Climate Change Change in Water Flow Land-Use Change Changing Chemical Inputs Aquatic Invasive Species Harvest Impact of Change on Freshwater Bodies Physical Transformations 6. Summary 2 Department of zoology,B.N College,P.U Page 3 Aquatic ecosystem part 1 4 1. Learning Objectives After the end of this module you will be able to 1. Understand the concept of fresh water ecosystem. 2. Understand the characteristics of the Lentic ecosystems. 3. Know the communities of lentic ecosystems and their ecological adaptations. 4. Know properties of Lake Ecosystems and their types. 5. Understand the major changes that are causing the threats to freshwaters ecosystems. 2. Introduction Freshwater ecology can be interpreted as interrelationship between freshwater organism and their natural environments.
    [Show full text]
  • A Primer on Limnology, Second Edition
    BIOLOGICAL PHYSICAL lake zones formation food webs variability primary producers light chlorophyll density stratification algal succession watersheds consumers and decomposers CHEMICAL general lake chemistry trophic status eutrophication dissolved oxygen nutrients ecoregions biological differences The following overview is taken from LAKE ECOLOGY OVERVIEW (Chapter 1, Horne, A.J. and C.R. Goldman. 1994. Limnology. 2nd edition. McGraw-Hill Co., New York, New York, USA.) Limnology is the study of fresh or saline waters contained within continental boundaries. Limnology and the closely related science of oceanography together cover all aquatic ecosystems. Although many limnologists are freshwater ecologists, physical, chemical, and engineering limnologists all participate in this branch of science. Limnology covers lakes, ponds, reservoirs, streams, rivers, wetlands, and estuaries, while oceanography covers the open sea. Limnology evolved into a distinct science only in the past two centuries, when improvements in microscopes, the invention of the silk plankton net, and improvements in the thermometer combined to show that lakes are complex ecological systems with distinct structures. Today, limnology plays a major role in water use and distribution as well as in wildlife habitat protection. Limnologists work on lake and reservoir management, water pollution control, and stream and river protection, artificial wetland construction, and fish and wildlife enhancement. An important goal of education in limnology is to increase the number of people who, although not full-time limnologists, can understand and apply its general concepts to a broad range of related disciplines. A primary goal of Water on the Web is to use these beautiful aquatic ecosystems to assist in the teaching of core physical, chemical, biological, and mathematical principles, as well as modern computer technology, while also improving our students' general understanding of water - the most fundamental substance necessary for sustaining life on our planet.
    [Show full text]
  • Part 1 – Freshwater Ecology
    PART 1 – FRESHWATER ECOLOGY Physical and chemical properties of water · Water is 775 times as dense as air at 0 o C · Exists in liquid form at normal atmospheric temperature and pressure · Water is found on earth in three forms – liquid, solid and gas · Density – maximum density is at 4o C not at freeing point of 0 o C and expands as it freezes so ice floats · The boiling point of water is 100 o C · The H20 molecule is polar and hydrogen bonding is present · Water molecules are attracted to other water molecules termed cohesion · Cohesion of water molecules at the surface of a body of water (surface tension) is very high · Water is attracted to other types of molecules termed adhesion · Water is an excellent solvent for ions and polar molecules · Capillary action due to stickiness (cohesion) of water molecules allows water to go up a small tube 1 Water Cycle 97 % of the water on earth is salt water in the ocean. Of the 3% of water that is fresh water, 2% is frozen in ice caps and only 1% is usable by organisms as liquid water or water vapor found in lakes, rivers, streams, ponds, in the ground water, and as vapor in the atmosphere The six major process in the water cycle are · Precipitation – water from the clouds fall to earth rain, snow, hail or sleet · Surface Runoff – water on the surface of the land that flows downhill into bodies of water such as streams, rivers, ponds, and lakes · Infiltration – rain water soaks into the ground through soil and rock layers under the soil with some remaining underground as groundwater · Evaporation – liquid water changes to a gaseous state as water vapor · Transpiration – water that has been absorbed by plants will evaporate through the leaves as water vapor · Condensation – water vapor is changed into a liquid Water vapors join dust particles to form clouds 2 Watershed A watershed or drainage basin is an area of land where water from rain and melting snow or ice drains downhill into a body of water, such as a river, lake, reservoir , wetland.
    [Show full text]
  • Chapter 10, “Legal Framework.”
    Lake Ecology: 1 Getting Your Feet Wet Introduction pollutants move through lakes, why exotic plants thrive in some lakes but not others, how quickly some To understand how to manage a lake, you must lakes will fill in, and other dynamics. Even as this know something about the lake itself. This is not trove of lake knowledge builds, however, there con- easy because lakes are complex, dynamic biological tinue to be many unanswered questions. This chapter systems that both influence and are influenced by provides an introduction to what is currently under- their environment. Countless examples can be found stood about how New York State lakes function. of how lakes and their environments interact. Just ask the people who live in the western Adirondacks A lake by any other name or Central New York and must contend with lake effect snowstorms that form over the Great Lakes The term “lake” will be used throughout this each winter. In short, lakes are more complex than manual as the general term encompassing ponds and the simple concept of big fish eating little fish. While reservoirs as well as true lakes. While everyone has this is a prominent feature of lake environments, and some idea of the differences among these ponded a microcosm of the complex interactions that govern waters, and while some legal distinctions are unique lake ecology, it is much too simplified. to each, no hard and fast boundaries separate ponds The study of freshwater systems, including lakes, from lakes from reservoirs in New York State. All is known as limnology.
    [Show full text]
  • Aquatic Ecosystems
    Aquatic Ecosystems The sea, once it casts its spell, holds one in its net of wonder forever. - Jacques Ives Cousteau 1 Aquatic Ecosystems ● Aquatic ecosystems, like those on land, have a series of abiotic factors that influence what organisms can survive there. ● Salinity is the amount of dissolved salt in the water. ● Salt is formed when rainwater dissolves rocks, releasing minerals into the water. 2 ● Water temperature, which is mostly influenced by sunlight. 3 ● Availability of sunlight, which decreases with water depth. Bering Sea, 1300 ft below the surface. Oceandoctor.org 4 ● Oxygen gas, which is dissolved in areas of turbulent water (waves and rapids). Whirlpool Rapids Gorge, Niagara River, NY 5 ● Plant nutrients such as nitrates and phosphates, which runoff from land. Algae Blooms, Western Lake Erie 6 ● Turbidity, or the cloudiness of the water, is caused by soil eroded from land. Confluence of Mississippi River(flows from right) and Minnesota River(flows from top) 7 Types of Aquatic Organisms ● Plankton are free-floating or weakly swimming. ● Phytoplankton are plant-like and include algae. ● Zooplankton are animal-like, including organisms like single-celled protozoa or jellyfish. ● Nekton are strong swimmers and consumers. ● Fish, whales, sea turtles, etc. 8 ● Benthos are bottom-dwellers that either anchor themselves to bottom structures or walk along the sea floor. ● Sea stars, lobsters, mussels, etc. ● Decomposers break down dead organisms and wastes into nutrients that can be re-used. ● Bacteria. 9 Lakes and Ponds ● Lakes and ponds contain standing water, some of which is too deep for emergent vegetation. ● Emergent vegetation includes plants that are rooted to the bottom and emerge above the water’s surface.
    [Show full text]
  • Fish in the Zone
    Illustrations by Bill Reynolds ▼ oung Y Fish in the naturalists Zone During the year, fish travel between zones of plant and animal life. Fish all have their favorite spots in a lake. If you fish, you’ll learn where certain fish are most likely to be found. Why does a fish choose to live in one part of the lake rather than another? Where fish hang out depends on the time of year. As weather changes from season to sea- son, conditions in a lake change. For example, as weather gets warmer, some parts of the lake warm up. Then fish might move to a different place, or zone, to find food and shelter. Fish also change zones as they grow. Like babies, larval yellow perch—average newly hatched fish need different kinds of food length 6 millimeters (less than one-quarter inch) and shelter than grown-up fish do. This story follows young yellow perch from spring through winter. As the seasons change and the perch grow, they travel to new lake zones. By Roland Sigurdson May–June 2012 47 grow there and her eggs need plants. After about 15 days, larvae hatch Her eggs come out as long, jellylike rib- from the eggs. Less than a quarter- First Home bons, some more than 6 feet long. The inch long and just beginning to grow In April the sun’s rays warm the lake ice, chunks. The wind blows the ice chunks ribbons get tangled around the under- fins, perch larvae don’t look much like causing millions of tiny cracks.
    [Show full text]
  • Understanding Lake Ecology
    BIOLOGICAL PHYSICAL lake zones formation food webs variability primary producers light chlorophyll density stratification algal succession watersheds consumers and decomposers CHEMICAL general lake chemistry trophic status eutrophication dissolved oxygen nutrients ecoregions biological differences The following overview is taken from LAKE ECOLOGY OVERVIEW (Chapter 1, Horne, A.J. and C.R. Goldman. 1994. Limnology. 2nd edition. McGraw-Hill Co., New York, New York, USA.) Limnology is the study of fresh or saline waters contained within continental boundaries. Limnology and the closely related science of oceanography together cover all aquatic ecosystems. Although many limnologists are freshwater ecologists, physical, chemical, and engineering limnologists all participate in this branch of science. Limnology covers lakes, ponds, reservoirs, streams, rivers, wetlands, and estuaries, while oceanography covers the open sea. Limnology evolved into a distinct science only in the past two centuries, when improvements in microscopes, the invention of the silk plankton net, and improvements in the thermometer combined to show that lakes are complex ecological systems with distinct structures. Today, limnology plays a major role in water use and distribution as well as in wildlife habitat protection. Limnologists work on lake and reservoir management, water pollution control, and stream and river protection, artificial wetland construction, and fish and wildlife enhancement. An important goal of education in limnology is to increase the number of people who, although not full-time limnologists, can understand and apply its general concepts to a broad range of related disciplines. A primary goal of Water on the Web is to use these beautiful aquatic ecosystems to assist in the teaching of core physical, chemical, biological, and mathematical principles, as well as modern computer technology, while also improving our students' general understanding of water - the most fundamental substance necessary for sustaining life on our planet.
    [Show full text]
  • Largest Zone of the Lake Is? 1
    11 ÷ªÙÞœüŒî¦ô¢Ù 4 íƇvñ÷J 2020 email: [email protected] Ecology and Environment 8 Marks Question Largest zone of the Lake is? 1. Describe lake as an ecosystem giving H Still deeper are the submerged plants such examples for the various zones and the 4 Marks Questions as Limmetic biotic components in it? ⎯→ Hydrilla Zone 1. What is summer stratification? Explain. A. Lake eco system: To understand the funda- ⎯→ Chara Littoral A: During summer in temperature lakes, the ⏐ Zone mentals of an aquatic ecosystem, let us take density of the surface water decreases ⎯→ Potamogeton a 'lake' as an example. This is fairly a self- H because of increase in its temperature sustainable unit and rather a simple exam- The free bloating vegetation includes ° ⎯→ (21-25 C). This ‘upper more warm water ple that explains even the complex interac- Pistia layer’ of a lake is called epilimnion. ⎯→ tions that exists in an aquatic ecosystem. Wolffia Profundal Below the epilimnion there is a zone in Lake Ecosystem Zone Lakes are large inland water bodies con- ⎯→ Lemna (duck weed) which the temperature decreases at the taining standing/ still water. They are deeper ⏐⎯→ Azolla rate of 1°C per meter in depth and it is than ponds (pond is not an ideal example as it ⎯→ Eclihornia Target-2020 called thermocline / metalimnion. The is very shallow). Most lakes contain water H The phytoplankton of the littoral zone bottom layer is the hypolimnion where throughout the year. In deep lakes, light can- → cosinodisus Junior Inter water is relatively cool. Stagnant and not penetrate more than 200 meters, in depth.
    [Show full text]