Ecology and Ecosystem.pdf

ECOLOGY ❑ The term Ecology’ was derived from two Greek words, OIKOS (means house) and LOGUS (means study of) to denote the relationship between the organisms and their environment. ❑ Ecology is a branch of science which deals with the study of inter- relationship bet...

ECOLOGY ❑ The term Ecology’ was derived from two Greek words, OIKOS (means house) and LOGUS (means study of) to denote the relationship between the organisms and their environment. ❑ Ecology is a branch of science which deals with the study of inter- relationship between biotic and abiotic components of nature as well as relationship among the individuals of the biotic components. ❑ Ecology is studied at many levels, including organism, population, community, ecosystem, and biosphere. Classification of Ecology The important sub-divisions of ecology are animal ecology and plant ecology. we can classify ecology into following branches:  ECOSYSTEM ❑ The term ecosystem was coined in 1935 by the Oxford ecologist Arthur Tansley to encompass the interactions among biotic and abiotic components of the environment at a given site. ❑ The function of ecosystem is related to energy flow and material cycles within and outside the system. Types of Ecosystem There are two main types of ecosystem. 1. Natural ecosystem – It is a naturally produced biological environment found in nature. It includes deserts, forests, grasslands, lakes, mountains, ponds, rivers, oceans, etc. 2. Artificial ecosystem – It is an artificial environment which is created and maintained by man. It includes an aquarium, crop fields, gardens, parks, zoo, etc. ECOLOGY AND ECOSYSTEM 11  Ecology derived from two Greek word “oikos” means house, habitation or place of living & “logos” means Ecology study. Definition: Ecology is the study of interrelationship between living organism and their physical and biological environment. Biological environment = Biotic factors Physical environment = Abiotic factors 12 Biotic Factors 13 Abiotic Factors 14  The inter-relationship between organisms in population and diverse communities Objectives of The temporal (sequential) changes (seasonal, annual, ecological successional etc) Structural adaptation and functional adjustments study The behavior under natural conditions The development in the course of evolution The biological productivity and energy flow in natural system 15  Helps us to tackle problems like pollution, floods, O3 depletion, global warming Is necessary in maintaining ecological balance and understanding different cycles (oxygen, nitrogen, sulfur, carbon etc.) Scope of ecology Helps in protecting flora and fauna We can maintain balance in nature and can prevent ecological disasters Plays an important role in human welfare, agriculture, conservation of wildlife. 16   Classification of ecology 1) Autecology 2) Synecology Autecology: It deals with the study of individual organism or an individual species. In other words it is study of inter relationship between individual species or its population and environment.e.g. a tree in forest Synecology : it deals with the study of group of organism or species which are associated together as a unit. e.g. a forest. It is concerned with structure, nature, development of that community 17 Further subdivisions of ecology is based on following: 1) Based on the taxonomic affinities : According to this ecology is divided in two part: Plant ecology and animal ecology 18 2) Based on the habitats Ecology Aquatic Terrestrial Ecology Ecology Grass Land Marine Ecology Ecology Fresh water Forest Ecology Ecology Stream Ecology Desert Ecology 19 3)Based On the level of organization: Depending upon the level of organism synecology can be divided into may types : Desert Ecology Autecology Synecology Population Ecology Community Ecology Ecosystem Ecology 20 The Ecosystem Definitions of ecosystem: 1. All organisms, their interactions with one another and their environments make up an ecosystem. 2. It is a community of interdependent organisms together with the environment. 3. Any unit that include all of the organisms in a given area interacting with the physical environment, so that a flow of energy leads to clearly defined trophic structure, biotic diversity and material cycles within the ecosystem. 21  Ecology Definition: Ecology derived from two Greek word “oikos” means house, habitation or place of living & “logos” means study. Ecology is the study of the interrelationship between living organism and their physical and biological environment. 22 Types of ecosystem Ecosystem can be Natural or Artificial a) Natural ecosystems: These operate under the natural conditions without any major interference by man. Further it can be classified: 1) Terrestrial Ecosystem 2) Aquatic Ecosystem 23 b) Artificial Ecosystem These are maintained artificially by man where by addition of energy and planned manipulation, natural balance is disturbed regularly. E.g. Cropland ecosystem 24 1)Terrestrial Ecosystem: Eg: Forest ,Grassland ,Desert 2) Aquatic Ecosystem: a) Fresh water :- which may be lotic (e.g. running water as stream, rivers) or lentic (e.g. standing water as lake, pool) b) Marine ecology :- Deep bodies as a ocean 25 26 Characteris It is a major structural and functional unit of tics of Ecology. Ecosystem Its structure is related to its species diversity; the more complex ecosystem have species diversity and vice versa. The relative amount of energy needed to maintain an ecosystem depend on its structure. The more complex the structure, the lesser the energy it needs to maintain itself. It matures by passing from less complex to more complex states 27 Structural features 1. Biotic structure The plants, animals and microorganism present in an ecosystem form the biotic component. a) Producers: They are mainly the green plants, which can synthesize their food themselves by making use of carbon dioxide present in the air and water through the process of photosynthesis. ‘Photoautotrophs’ = (Photo=light, auto=self; troph=food). 28 Structural features b) Consumers: all organisms which get their organic food by feeding upon other organism are called consumers, which are following types: i. Herbivores (plant eaters): e.g. Rabbit, insect, goat, cattle. ii. Carnivores (meat eaters): e.g. Snake, cat, fox etc. iii. Omnivores: e.g. humans, rat, fox etc. iv. Detritivores: (Detritus feeders or saprotrophs) v. Predetor:(Kills other organism for food) e.g. wolf, beer. 29  c) Decomposers: They derive their nutrition by breaking down the complex organic molecules to simpler organic compound and ultimately into inorganic nutrients. Structural e.g. bacteria, fungi etc. features 30 31 32 primary consumers Also known as HERBIVORES , such as: mice, deer, cows, and elephants Herbivores eat ONLY PLANTS 33 Secondary Consumers Are CARNIVORES – they eat only animals If the animal must be killed before it is eaten, the secondary consumer is known as a predator. However, sometimes the animals does not have to be killed to be eaten. 34 Secondary Consumers Omnivores they eat Both : Plants and Animals 35  Scavengers Feeds on the bodies of dead organisms. 36 37 Decomposers Break down wastes and dead organisms, and so complete the cycle by returning nutrients to the ecosystem. (to the soil or water and carbon dioxide to the air and water) 38  The producers of an ecosystem take up several basic inorganic nutrients from their nonliving environment. These nutrients get transformed into biomass of Biogeochemical the producers. Cycle Then they are utilized by the consumer population and ultimately returned to the environment with the help of reducers and decomposers. The cyclic exchange of nutrients materials between living organisms and their nonliving environment is called biogeochemical cycle. 39 1) Biogeochemical cycles helps as to understand the flow of pattern various nutrients, water, gases etc. needed for development of life 2) Hydrological cycle deals with the interchange water between living organisms & environment. 3) Gaseous cycle deals with the interchange of gases like Oxygen, Nitrogen, Carbon Dioxide. 4) The sedimentary cycles deals with the interchange of minerals like sulphur, phosphorus. 40 Water cycle 41 ▪ Water never leaves the Earth. It is constantly being cycled through the atmosphere, ocean, and land. ▪ This process, known as the water cycle, is driven by energy from the sun. ▪ The water cycle is crucial to the existence of life on our planet. 42 Evaporation Hydro_cycle_sm Evaporation: Process by which the sun heats up liquid water and changes it to a gaseous form (vapours). 43 Condensation Hydro_cycle_sm Condensation: Process by which water rises into the atmosphere, cools and becomes a liquid again. 44 Precipitation Hydro_cycle_sm Precipitation: Process by which water condenses and falls back to the earth. 45 Transpiration Hydro_cycle_sm Transpiration: The process of evaporation from plants. Factors affecting transpiration: Sun light intensity, relative humidity, soil moisture availability, wind movement, types of plants. 46 Runoff Hydro_cycle_sm Runoff: Water that collects in rivers, streams, and oceans 47 48  An element The basis of life of earth What Is Carbon? Found in rocks, oceans, atmosphere 49 Plants Use Carbon Dioxide Plants pull carbon dioxide from the atmosphere and use it to make food –— photosynthesis. The carbon becomes part of the plant (stored food). 50  Animals Eat Plants When organisms eat plants, they take in the carbon and some of it becomes part of their own bodies. C is also released back as CO2 after respiration and combustion 51 Plants and Animal Die When plants and animals die, most of their bodies are decomposed and carbon atoms are returned to the atmosphere. Some are not decomposed fully and end up in deposits underground (oil, coal, etc.). 52 Carbon Slowly Returns to Atmosphere Carbon in rocks and underground deposits is released very slowly into the atmosphere. This process takes many years. 53 54 Carbon cycle 55 Carbon in Oceans Additional carbon is stored in the ocean. Animals die and carbon substances are deposited at the bottom of the ocean. Oceans contain earth’s largest store of carbon. 56 57  Fossil fuels release carbon stores very slowly Burning anything releases more carbon into Human Impact atmosphere — especially fossil fuels Increased carbon dioxide in atmosphere increases global warming Fewer plants mean less CO2 removed from atmosphere 58  Burn less, especially fossil fuels Promote plant life, especially trees What We Need to Do 59 Nitrogen Cycle 60 Forms of Nitrogen Urea → CO(NH2)2 Ammonia → NH3 (gaseous) Ammonium → NH4 Nitrate → NO3 Nitrite → NO2 Atmospheric nitrogen →N2 Organic N (Amino acids--RCONH2) 61 Roles of Nitrogen Plants and bacteria use nitrogen in the form of NH4+ or NO3- It serves as an electron acceptor in anaerobic environment Nitrogen is often the most limiting nutrient in soil and water. 62  The Nitrogen Cycle (4) Denitrification (1) Nitrogen Fixation Nitrogen Cycle (3) Nitrification (2) Ammonification 63  Atmospheric nitrogen (about 78% of our air) is converted to ammonia or nitrates. N N Atmospheric Nitrogen (N2) N N Ammonia (NH3) Nitrates (NO3) Nitrogen combines Nitrogen combines with Hydrogen to make with Oxygen to make Ammonia Nitrates 64  It is one of nature’s great ironies… Nitrogen is an essential component of DNA, RNA, and proteins the majority of the air we breathe is nitrogen yet most living organisms are unable to use nitrogen as it exists in the atmosphere. 65  “Nitrogen Fixation” is the process that causes the strong two-atom nitrogen molecules found in the atmosphere to break apart so they can combine with other atoms. Nitriteion Oxygen Hydrogen N Nitriteion Nitriteion N Hydrogen N N Nitriteion N Oxygen N Nitrogen gets “fixed” when it is combined with oxygen or hydrogen. 66 Free Living Bacteria (example of nitrogen fixation) Highly specialized bacteria live in the soil and have the ability to combine atmospheric nitrogen with hydrogen to make ammonia (NH3). N N H N H3 Free-living bacteria live in soil and combine atmospheric nitrogen with hydrogen (NH3) Nitrogen changes into ammonia Bacteria 67  Legume plants Symbiotic Relationship Bacteria Bacteria live in the roots of legume family plants N and provide the plants with ammonia (NH3) in exchange for the plant’s NH3 carbon and a protected home. N Roots with nodules where bacteria live Nitrogen changes into ammonia. 68 Ammonification: Bacteria (decomposers) break down amino acids from dead animals and wastes into ammonium. Bacteria decomposers break down amino acids into ammonium 69 Microorganisms convert the organic nitrogen to ammonium. The ammonium is either taken up by the plants (only in a few types of plants) or is absorbed into the soil particles. Ammonium (NH4) in the soil is stored up to later be changed into inorganic nitrogen, the kind of nitrogen that most plants can use. Bacteria converts organic nitrogen to ammonium (NH4) Ammonium (NH4) is used by some plants Bacteria Ammonium (NH4) is stored in soil. 70 Nitrification: Nitrifying bacteria in the ground combine ammonia with oxygen to form nitrites. Then another group of nitrifying bacteria convert nitrites to nitrates which green plants can absorb and use. Nitrifying bacteria in soil combine ammonia with oxygen Ammonia changes to nitrites Nitrifying bacteria in soil convert nitrites to nitrates Ammonia Nitrites Nitrates Plants absorb nitrates and grow! (NH3) (NO2) (NO3) 71 Denitrification: The conversion of nitrates (NO3) in the soil to atmospheric nitrogen (N2) thereby replenishing the atmosphere. Marsh Nitrogen in atmosphere (N2) Nitrates (NO3) in Soil 72 Denitrifying bacteria live deep in soil and in aquatic sediments where conditions make it difficult for them to get oxygen. The denitrifying bacteria use nitrates as an alternative to oxygen, leaving free nitrogen gas as a byproduct. They close the nitrogen cycle! Marsh Nitrogen in atmosphere closes the nitrogen cycle! (N2) (NO3) Denitrifying bacteria live deep in soil and use nitrates as an alternative to oxygen making a byproduct of nitrogen gas. 73 74 Nitrogen cycle 75  Transfer of Energy in an Ecosystem 76  Herbivores – eat plants Transfer of Energy in an Omnivores Carnivores Ecosystem –eat both plants & CONSUMER – eat animals animals Scavengers – feed only on dead organisms 77  Energy flow heat Producers Consumers Decomposers heat This pattern of energy flow among different organisms is the TROPHIC STRUCTURE of an ecosystem. 78  To maintain life energy is required. Energy enters in an ecosystem from solar radiations. In earth’s atmosphere about 15x108 cal/m2/year of solar energy is present. Out of which only 47% of the energy reaches the earth surface Energy Flow and only 1-5% of energy reaching the ground is converted into chemical energy by green plants. in Ecosystem The plants make use of raw material from the environment in the form of water, salts and carbon dioxide to prepare food with the help of sun light. Thus energy form the sun enters the living world through photosynthetic organisms and passes on from one organism to another in form of food. 79  The flow of energy is unidirectional and non cyclic. Energy enters the ecosystem form solar radiation and converted into chemical energy by producers, from them energy passes to lower tropic level to higher one. This one way flow of energy is governed by laws of thermodynamics which state that : a) The energy can not be created not destroyed but may be transferred from one from to another b) During the energy transfer there is degradation of energy from concentrated form to a dispersed form(Heat) 80 No energy transformation is 100% efficient; it is always accompanied by some dispersion or loss of energy in the form of heat. Heat energy is not utilized by biological system and ultimately lost from the body 81 82  Models for energy flow in ecosystem The flow of energy through various trophic levels in an ecosystem can be explained by: 1) Single channel energy flow model 2) Y shaped or double channel energy flow model 3) Universal energy flow model 83 Ecological Pyramid This shows how energy is transferred and changed when going up the pyramid. 84  A. Pyramid of Energy – shows the amount of energy in calories (Kcal / Three Types cal) of Ecological B. Pyramid of Biomass – shows the Pyramid biomass of all organisms and individuals C. Pyramid of Numbers – shows the number of individuals feeding at 85 Pyramid of Energy 86 Pyramid of Biomass 87 Pyramid of Numbers 88 Food Chain Organisms in one level feed upon organisms at the lower level. 89  Trophic Levels Each link in a food chain is known as a trophic level. Trophic levels represent a feeding step in the transfer of energy and matter in an ecosystem. 90 Trophic Levels E Tertiary consumers- top carnivores N Secondary consumers- E small carnivores R Primary consumers- Herbivores G Producers- Autotrophs Y 91 92 Types of Food chain 93 94 Significance of Food Chain Biological magnification (Biomagnification) *Harmful chemicals like insecticides and pesticides which are used to protect crops from insects and pests are absorbed by plants and enter the food chain. *Since these chemicals are non biodegradable, they get accumulated at every trophic level and their concentration increases. *The increase in concentration of harmful chemicals in the bodies of organisms at higher trophic levels is called biological magnification. 95 Biological magnification (Biomagnification) Biomagnification of DDT Biomagnification of Mercury 96 Biological magnification (Biomagnification) The biomagnification of pollutants can be estimated with the help of Biological Concentration Factor (BCF). Concentration of toxic material in organism Concentration of toxic material in Environment BCF = 97 Food Web It is a network of interacting food chains. 98  Food Web Food web- shows all possible feeding relationships in a community at each trophic level Represents a network of interconnected food chains 99  Food web :- Food web is a group of several interconnected food chains. In a food web an organism gets food from more than one group of organisms. Examples of Terrestrial food web 100 Examples of Aquatic food web 101  Forest Ecosystem Grassland Ecosystem Desert Ecosystem Aquatic Ecosystem Estuarine Ecosystem Major Ecosystems 102 Major ecosystems Determined primarily by precipitation Forests (> 75 cm rain per year) Grasslands (30-75 cm rain per year) Deserts (< 30 cm rain per year) 103 Tropical Forest: Vertical stratification with trees in canopy blocking light to bottom strata. Many trees covered by epiphytes (plants that grow on other plants). 104 105 Example of Tropical, Dry Forest 106 Temperate Deciduous Forest: Mid-latitudes with moderate amounts of moisture, distinct vertical strata: trees, shrubs, herbaceous sub- stratum. Loss of leaves in cold, many animals hibernate or migrate then. Original forests lost from North America by logging and clearing. 107 Deciduous forest 108 http://www.ccet.ua.edu/hhmi/images/Autumn.JPG Coniferous forest: Largest terrestrial biome on earth, old growth forests rapidly disappearing, usually receives lots of moisture as rain or snow. 109  Coniferous forest 110 http://www3.newberry.org/k12maps/module_07/images/coniferous.jpg Desert: Sparse rainfall (< 30 cm per year), plants and animals adapted for water storage and conservation. Can be either very hot, or very cold (e.g. Antarctica) 111  Desert http://pangea.stanford.edu/~hsiao/desert.jpg 112 Temperate Grassland: Marked by seasonal drought and fires, and grazing by large animals. Rich habitat for agriculture. 113 Estuary: Place where freshwater stream or river merges with the ocean. Highly productive biome; important for fisheries. Often heavily polluted from river input so many fisheries are now lost. 114  ECOSYSTEM BIOTIC ABIOTIC FACTORS FACTORS Forest Ecosystem High rainfall Large number of organism and flora Highly diverse population Stability of ecosystem is very sensitive 116 Abiotic Biotic Sunlight  Primary producer Temperature  Herbivores  Carnivorous Precipitation  Omnivores Water or Moisture  Detritivores Soil or Chemical content 117  What is forest? A forest is a community of trees, shrubs, herbs, and associated plants and organisms that cover a considerable area that use oxygen, water and soil nutrients as the community attains maturity and reproduces itself. 118 Forest Ecosystem ▪ An ecosystem is a biological community of interacting organisms and their physical environment. ▪ A forest ecosystem is a terrestrial unit of living organisms (plants, animals and microorganisms), all interacting among themselves and with the environment (soil, climate, water and light) in which they live 119  Meaning that every organism depends on every other living and nonliving element of the system. A Forest Living components of the forest = producers (able to make food), consumers (eats other producers and Ecosystem Is consumers), and decomposers (break down organic “Interdependent” material). Non-living components = soil, water and climate. 120  ABIOTIC FACTORS BIOTIC FACTORS Sun: Provides light for photosynthesis Producers: Plants that are a source of food and/or O2 Soil: Provides minerals and nutrients for Primary Consumers: Herbivores that feed plants(producers) to grow. on producers FACTORS OF Water: Helps in Photosynthesis, Secondary Consumers: Carnivores that AN hydration of flora and fauna, maintains feed on primary consumers and/ or other optimum climate secondary consumers ECOSYSTEM Air: Provides CO2 for photosynthesis and Decomposers: Organisms that O2 for respiration decompose dead matter and supply minerals and other substances for the improvement to the soil 121 FOOD WEB Within a food web there are ‘predators’, that is, animals that hunt and prey on smaller animals for a source of food. In a food chain, the transfer of energy begins with the producer and ends with the highest order consumer, as follows: tree → insect → mouse → owl → eagle However, in a food web the interaction between organisms becomes more complex. 122 For example: 123 The natural vegetation of India can be divided into 6 main types. 124  Tropical evergreen forest This type of vegetation is found in areas which are not more than 900 mts above the sea level and receive the rainfall more than 250 cm and the temperature ranges between 250c and 270c. 125  Temperature and humidity are responsible for it They grow about 60mts tall. Canopy is formed In India, most of these forests are found on the western side of the Western Ghats, in the North-Eastern states and the Andaman Nicobar Islands. They occupy 2.6 lakh hectares. 126 Ebony, Mahogany & Rose Wood trees Rubber Tree Bamboo Bushes 127 Deciduous Monsoon Forests They cover a greater part of India. They found in regions where the rainfall is between 75 cm and 250 cm. It forms 65.5% of the total area of forests. Since India is having monsoon climate, this type of forest is distributed widely. They shed their leaves during dry winter. They are also called tropical deciduous forests. 128 Teak, sal 129 Tropical Grassland This type of vegetation is found in the central parts of the Peninsular Plateau, border areas of Thar desert to the west of Aravalli hills where the annual rainfall is between 60 cm and 75 cm. These forests have trees with short trunks Babool, Seesum types of grass are seen here. 130 Tropical Grassland 131 Mangrove Forests These forests are formed due to tides. They are found along the deltas and estuaries of rivers that are subjected tides. The deltas of river Ganges, Godavari, Mahanadi and Krishna have these forests. In Ganges delta, there are plenty of Sundari trees and hence the forests are known as ‘Sundarbans’ The total area of mangrove forest is 4.4 thousand km2 132 Mangrove Forests 133 Desert Forests This type of vegetation is found in regions where the annual rainfall is less than 50 cm, Rajasthan’s Thar Desert, and the adjacent parts of Punjab, Haryana and Gujarat have this type of vegetation. The trees which grow here are short, have deep roots, thick leaves and thorns. Date palms are common near the oasis. Babul, palms and cactus are the important trees. 134 Desert Forests 135 Alpine forests of Himalayan Different types of forests are found here. As height increases the tropical type of climate changes in to the polar type of climate. According to the changes in climate, various types of plants are found. The important types of trees growing in this type of forest are sal, byra, toon, silver spruce, laurel etc. These trees have pointed leaves. 136 Importance of Forests Forests are a very essential natural resources. They provide raw materials to industries such as – Timber, bamboo, cane, gum, medicinal plants, shrubs etc. They provide fodder to animals. Forests provide moisture in the atmosphere and lower the temperature. They obstruct the rain-bearing winds and cause rainfall. Prevent soil erosion and preserve the fertility. Forests provide a home for many animals and birds. Forests help to preserve the ecological balance. They provide animal sanctuaries which attract tourists. 137 Conservation of Forests Protection of forests from human beings, animals, and natural disasters is called Conservation of forests. Indian forests areas are gradually decreasing, because of expansion of agriculture, animal-grazing, construction of road and rail routes, irrigation projects, forest fires, mining forest, fires etc are the main causes for the destruction of forests. 138 Methods of Conservation Cutting down dried-up and abrasing trees which causes forest fires. Protecting against diseases. Planting saplings Sowing seeds Guarding against illegal cutting of trees. Avoid domestic animals to graze in the forest Creating awareness among people. Social forestry projects. 139 Desert Ecosystem High temperature, intense sunlight and low water Flora and fauna are very poorly developed and scarce Organisms are xeric adaptive Scarcely populated 140 Types of desert Sand desert Stony desert Rock desert Plateau desert Mountain desert Cold desert 141 Types of desert Sand desert Stony desert 142 Types of desert Rock desert Plateau desert 143 Types of desert Mountain desert Cold desert 144 Features of desert ecosystem Rainfall Temperature Soil light Plants and animals are adapted to live in extremities 145 Functions of desert ecosystem Solar energy resource Mineral resource 146 Grassland Ecosystem Marginal rainfall Vegetation is dominated by grasses Unimproved wild-plant communities Densely populated 147 Types of Grassland Ecosystem Tropical grassland Temperate grassland Others 148 Grassland of India The Himalayan pasture belt Terai region - Sal forest ecosystem - tall elephant grass (five meters) Shola grasslands - Western Ghats, Nilgiri and Annamalai ranges 149 Function of grassland ecosystem Grassland provide food Grasslands Are Breeding Areas Human habitat 150 Uses of grassland Grasslands are the grazing areas of many rural communities. Grass is also used to thatch houses and farm sheds. Fuel wood 151 Threats to grassland ecosystems? Overgrazing Converting grassland to farmland Forest Fires 152 Aquatic Ecosystems 153 What is an aquatic ecosystem? Aquatic ecology is the study of water based ecosystems. They are an area of water, in which ‘significant’ biological activity can occur This definition excludes most groundwater systems Aquatic ecosystems can involve flowing or still water, and can be fresh or saline 154 Aquatic Ecosystem Low temperature and sunlight Soil and vegetation is submerged Flora and fauna had adapted Densely populated. 155 How many types are there? Several, depending on how close we look! Freshwater (Limnology) Lakes (lentic) Rivers (lotic) Groundwater Brackish water (inter-tidal) Marine water (Oceanography) Anthropogenic waters (i.e drinking water) 156 Features of aquatic ecosystem Light and temperature Current Chemistry Competitive organism 157 Function of Aquatic Ecosystem Recycles nutrients Purify water Responsible for proper rainfall Attenuate floods Recharge ground water 158 Freshwater Ecosystems Include: Ponds, Lakes, Streams, Rivers, and Wetlands Wetlands– Area of land that are periodically under water or whose soil contains a great deal of moisture Normally on the edge of a pond , lake or river. 159 Characteristics of Aquatic Ecosystems Factors such as temperature, sunlight, oxygen, and nutrients determine which organisms live in which area of the water. Three groups of aquatic organisms include: Plankton - mostly microscopic organisms that float or drift freely in the water, and can be microscopic animals (zooplankton) or microscopic plants (phytoplankton). Nekton - are all organisms that swim actively in open water, independent of currents. Benthos - are bottom-dwelling organisms of the sea or ocean and are often attached to hard surfaces. 160 Lakes and Ponds Can form naturally where groundwater reaches the Earth’s surface. Humans intentionally create artificial lakes by damming flowing rivers and streams to use them for power, irrigation, water storage, and recreation (reservoir). Structured into horizontal and vertical zones. The types of organisms present depend on the amount of sunlight available. 161 Life in a Lake Littoral zone -shallow zone where light reaches the bottom and nurtures plants, and aquatic life is diverse and abundant. In open water, plants, algae, and some bacteria capture solar energy to make their own food during photosynthesis. Benthic zone - region near the bottom of a pond, lake or ocean which is inhabited by decomposers, insect larvae, and clams. Some bodies of fresh water have areas so deep that there is too little light for photosynthesis. Bacteria live in the deep areas of freshwater. Eventually, dead and decaying organisms reach the benthic zone. 162 How Nutrients Affect Lakes Eutrophication -increase in the amount of nutrients, such as nitrates, in an aquatic ecosystem. As the amount of plants and algae grow, the number of bacteria feeding on the decaying organisms also grows. These bacteria use the oxygen dissolved in the lake’s waters. Eventually the reduced amount of oxygen kills oxygen loving organisms. 163 RIVER A river is usually cold and full of oxygen and runs swiftly through a shallow riverbed. As a river flows down a mountain, it may broaden, become warmer, wider, slower, and decrease in oxygen. A river changes with the land and the climate through which it flows. 164 Streams & Rivers Bodies of flowing water moving in one direction Found everywhere—they get their start at headwaters, which may be springs, snowmelt or even lakes Travel all the way to their mouths, usually another water channel or the ocean 165 Life in a River Mosses anchor themselves to rocks. Trout and minnows are adapted to the cold, oxygen rich water. Plankton can float in the warmer, calmer waters. Plants here can set roots in the river’s rich sediment. Fish such as catfish and carp also live in these calmer waters. 166 Rivers in Danger Industries use river water in manufacturing processes and as receptacles for wastes. People have used rivers to dispose of their sewage and garbage. These practices have polluted rivers with toxins, which have killed river organisms and made river fish inedible. Today, runoff from the land puts pesticides and other poisons into rivers and coats riverbeds with toxic sediments. 167 What factors can alter aquatic ecosystems? Artificial Succession- humans add N & P to water via fertilizer & sewage causing succession to happen faster = EUTROPHICATION 168 What factors can alter aquatic ecosystems? Water Pollution Excessive use of Fertilizers Industries Waste Disposal 169