Cycles of Matter - Biology Foundations PDF

Cycles of Matter Key Questions Recycling in the Biosphere How does matter move Energy passes in one direction from one trophic level to the next. through the biosphere? Eventually it escapes into the environment...

Cycles of Matter Key Questions Recycling in the Biosphere How does matter move Energy passes in one direction from one trophic level to the next. through the biosphere? Eventually it escapes into the environment as heat along the way. How does water cycle Energy in the form of sunlight is constantly entering the biosphere. But through the biosphere? Earth doesn’t receive a steady supply of new matter from space. Instead, What is the importance matter is recycled. Elements, such as oxygen, carbon, and hydrogen, of the main nutrient cycles? pass from one organism to another and from one ecosystem to another. How does nutrient They also pass among parts of the biosphere through closed loops availability relate to the primary called biogeochemical cycles. The flow of energy powers these cycles. productivity of an ecosystem? Cycles of matter involve biological processes, geological processes, and chemical processes. Human activity can also play an important role. Matter is transformed as it moves through these cycles. It is never created or destroyed—just changed. The processes involved in biogeochemical cycles can be classified in the following ways: Main Idea and Details Chart Make a main idea and details chart ▶ Biological Processes Biological processes consist of any and all using the green and blue headings activities performed by living organisms. These processes include in this lesson. Fill in the details as eating, breathing, “burning” food, and eliminating waste products. you read to help you organize the information. ▶ Geological Processes Geological processes include volcanic eruptions In Your Workbook Go and the formation and breakdown of rock. They also include major to your workbook to learn more movements of matter within and below the surface of the earth. about making a main idea and details chart. Complete the chart for ▶ Chemical and Physical Processes Chemical and physical processes Lesson 3.4. include the formation of clouds and precipitation. They also include the flow of running water and the action of lightning. Energy The MaTTer MiLL of Matt Nutrients are recycled through cles er Cy biogeochemical cycles. These cycles are powered by the one-way flow of energy through the biosphere. 68 Chapter 3 Lesson 4 ▶ Human Activity Mining and burning fossil fuels, and burning forests, affect the cycles of matter. So does clearing land for building and farming. Manufacturing and using fertilizers also influence cycles of matter. These cycles pass the same atoms and molecules around again and biogeochemical cycle again. Just think—carbon atoms in your body may once have been a process in which elements, chemical compounds, and other part of the tail of a dinosaur! forms of matter are passed from one organism to another and Key Question How does matter move through the biosphere? from one part of the biosphere Matter is recycled within and between ecosystems. to another ROOT WORDS The Water Cycle The term biogeochemical is formed Water constantly moves between the oceans, the atmosphere, and land. It by combining the words biological, can be inside organisms or outside them. Water molecules usually enter geological, and chemical. the atmosphere by evaporating from bodies of water or from plant leaves. When it evaporates, water becomes a gas called water vapor. Winds can transport water vapor over great distances. In cooling air, the vapor condenses into tiny droplets that form clouds. When the droplets become large enough, they fall to Earth’s surface as precipitation. This can be in the form of rain, snow, sleet, or hail. Precipitation can become runoff, flowing along the surface of land into a river or stream. It can also be absorbed into the ground, becoming groundwater. Groundwater enters plants through their roots or flows into bodies of water. If it penetrates deeply into the ground, it becomes part of underground reservoirs. Water that re-enters the atmosphere through transpiration or evaporation begins the cycle again. The Water Cycle This diagram shows the main processes in the Key Question How does water cycle through the biosphere? water cycle. Scientists estimate that Water continuously moves between the oceans, the atmosphere, it can take as long as 4000 years and land. Sometimes the water is outside living organisms and to complete one cycle. sometimes it is inside them. Water from Atmospheric Water falls to oceans and lakes Water (H2O gas) the surface as evaporates precipitation. and then Surface runoff condenses to leads through form clouds. Groundwater rivers to lakes is taken up by and oceans. plant roots and Some water then, through seeps into the transpiration, ground and released to the becomes atmosphere. groundwater. Ocean Groundwater Biological Physical/Chemical Lesson 3.4 InterActive Art 69  Nutrient Cycles Nutrients are chemical substances organisms need to build tissues and carry out life functions. Like water, they pass through organisms and the environment through biogeochemical cycles. The three most important cycles move carbon, nitrogen, and phosphorus through the biosphere. The Carbon Cycle Carbon is a major component of all organic The Carbon Cycle Carbon is compounds, including carbohydrates, lipids, proteins, and nucleic acids. found in several large reservoirs There are several major carbon reservoirs in the biosphere. For example, in the biosphere. In the atmosphere, carbon is found in calcium carbonate (CaCO3). This mineral is found it is found as carbon dioxide gas (CO2); in the oceans, as dissolved in animal skeletons and several kinds of rocks. Carbon and oxygen carbon dioxide; on land, in form carbon dioxide gas (CO2). CO2 is an important component of the organisms, rocks, and soil; and atmosphere and is also dissolved in oceans. Coal, oil, natural gas, and underground, as coal, petroleum, forests also are important carbon reservoirs. and calcium carbonate. Biological Human Geological activity Atmospheric Geological releases CO2. Carbon (CO2 gas) Physical/Chemical CO2 dissolves in rainwater. Burning of forests and fossil fuels releases CO2. CO2 dissolves in oceans and returns to the atmosphere. Forests Dissolved CO2 CO2 is taken up by producers during photosynthesis and released by cellular Fossil Fuels respiration. Consumers (coal, oil, and eat producers and Carbonate Green natural gas) release CO2 through Rocks Algae cellular respiration. Decomposition, pressure, and heat turn organic matter to fossil fuel over Geological activity millions of years. Carbon in turns marine Marine Sediments sediments into rock. 70 Chapter 3 Lesson 4 The figure to the left shows the carbon cycle. Notice how carbon often moves between different parts of the cycle as carbon dioxide. Stored carbon is found in organic matter, fossil fuels, rocks, and the skeletons of organisms. nitrogen fixation the process of converting nitrogen The Nitrogen Cycle All organisms need nitrogen to make amino gas into nitrogen compounds that acids and nucleic acids. Nitrogen exists as a gas (N2) in the atmosphere. plants can absorb and use – Nitrogen compounds such as ammonia (NH3), nitrate ions (NO3 ), denitrification – the process by which soil bacteria and nitrite ions (NO2 ) are found in soil. These compounds also exist in wastes and decomposing organic matter. Several forms of dissolved convert nitrates into nitrogen gas nitrogen can be found in the oceans and other large water bodies. ACADEMIC WORDS Nitrogen gas is the most common form of nitrogen on Earth. But The verb accumulate means only certain kinds of bacteria can use nitrogen gas directly. These “to collect or gather.” Carbon accumulates, or collects, in the soil bacteria use a process called nitrogen fixation to convert nitrogen and in the oceans where it cycles gas to ammonia. These bacteria live in the soil and on the roots of among organisms or is turned into certain plants, such as peanuts and peas. Other kinds of soil bacteria fossil fuels. convert ammonia into nitrates and nitrites. Primary producers use these compounds to make proteins and nucleic acids. Consumers eat producers and reuse the nitrogen to make their own proteins and nucleic acids. Decomposers release ammonia, nitrates, and nitrites from wastes and dead organisms. Producers can reuse these compounds. There are also some soil bacteria that convert nitrates The Nitrogen Cycle The atmosphere to nitrogen gas. The process of converting nitrates to nitrogen gas is the largest reservoir of nitrogen in is called denitrification. Denitrification provides the bacteria with the biosphere. Nitrogen also cycles energy. Humans also add nitrogen to the biosphere by manufacturing through the soil and through the and using fertilizers. Runoff often carries excess fertilizer into surface tissues of living organisms. water or groundwater. Atmospheric N2 gas is turned Nitrogen (N2 gas) into fertilizer and Some N2 gas is applied to crops. fixed by lightning. Excess may wash into rivers, streams, Fertilizer and the ocean as plant runoff. Bacteria fix Bacteria release N2 gas. Bacteria fix N2 gas through Crops N2 gas. denitrification. Bacteria Animals Bacteria Bacteria Dissolved Nitrogen Roots Soil Nitrogen (NH3, NO2–, Bacteria Green NO3–) Algae Biological Human Nitrogen is taken up by primary producers, Physical/Chemical reused by consumers, and released by excretion and decomposing matter. The Biosphere 71  Biological Phosphorus is mined, turned into fertilizer, Human and applied to crops. Excess may wash into Geological rivers, streams, and the ocean as runoff. Fertilizer plant Mine Crops Phosphate Rock Geological activity washes phosphates Soil from rock into the Animals Phosphates ocean. Dissolved Phosphates Green Phosphorus is taken up by primary Algae Geological activity producers, reused by consumers, turns marine sediments and released by excretion and into rock. decomposing matter. Phosphates in Marine Sediments The Phosphorus Cycle Phosphorus in the biosphere cycles among the land, ocean, sediments, and living The Phosphorus Cycle Phosphorus is essential to living organisms. organisms. Unlike other nutrients, It is an important part of molecules such as DNA and RNA. Although phosphorus is not found in significant phosphorus is important biologically, it is not abundant in the quantities in the atmosphere. biosphere. Phosphorus does not enter the atmosphere in large amounts. Phosphorus remains mostly on land and in the ocean as inorganic phosphate. On land it is found in phosphate rock and soil minerals. In the ocean, it may be dissolved or found in phosphate sediments. Rocks and sediments release phosphate as they wear down. Some phosphate stays on land and cycles between organisms and soil. Plants bind phosphate into organic compounds when they absorb it from soil or water. Organic phosphate moves through the food web to the rest of the ecosystem. Other phosphate washes into rivers and streams, where it dissolves. This phosphate may eventually make its way to the ocean, where marine organisms process and incorporate it into biological compounds. Key Question What is the importance of the main nutrient cycles? Organisms need nutrients to build tissues and carry out life functions. The main nutrient cycles move carbon, nitrogen, and phosphorus through the biosphere. Nutrient Limitation Primary productivity is the rate at which primary producers create organic material. If even one essential nutrient in an ecosystem runs short, primary productivity will be limited. A nutrient whose supply limits productivity is called a limiting nutrient. 72 Chapter 3 Lesson 4 Nutrient Limitation in Soil On many farms, growth of crop plants is limited by a lack of one or more nutrients in the soil. That’s why farmers use fertilizers! Most fertilizers contain large amounts of nitrogen, phosphorus, and potassium. These nutrients help plants Micronutrients grow better in poor soil. Micronutrients such as calcium, magnesium, sulfur, iron, and manganese are necessary in relatively small amounts. These elements are sometimes included in specialty fertilizers. Chemical fertilizers do not contain carbon. Plants get carbon from Potassium carbon dioxide during photosynthesis. All nutrient cycles work Phosphorus together like the gears in the figure to the right. If a nutrient runs short, the whole system slows down or even stops. Nutrient Limitation in Aquatic Ecosystems The open oceans of Nitrogen the world are nutrient-poor compared to many land areas. In saltwater environments, nitrogen is typically the limiting nutrient. Phosphorus is typically the limiting nutrient in freshwater environments. Sometimes an aquatic ecosystem receives a large input of a limiting interlocking nutrients nutrient. For instance, a heavy rain may cause runoff from heavily The movement of each nutrient fertilized fields. The extra nutrients can cause a dramatic increase in through ecosystems depends on the the amount of algae and other primary producers. If there are not movement of all the others, because enough consumers to eat the algae, an algal bloom can occur. During all are needed for living systems to function. an algal bloom, algae can cover the water’s surface and disrupt the functioning of an ecosystem. Key Question How does nutrient availability relate to the primary productivity of an ecosystem? The availability of nutrients may limit primary productivity, even when sunlight and water are plentiful. Apply Vocabulary The corn receives plenty of sunlight and water, Use the highlighted words from the lesson to but does not grow well. What might be complete each sentence correctly. preventing the corn from growing? 5. Write to Learn Answer the fourth clue to the 1. Bacteria convert nitrogen gas into ammonia mystery. Think about how nitrogen enters the using a process called ______. water. Is the increase in nitrogen in the water 2. Nutrients move between organisms, the caused by nitrogen fixation or denitrification? atmosphere, the land, and the water in a series of processes called ______. Critical Thinking 3. Explain How does the way that matter flows Recently, researchers discovered that levels through an ecosystem differ from the way that of dissolved nitrogen in the bay have energy flows? increased. Since human activity hasn’t changed much, which organisms in the bay 4. Relate Cause and Effect A farmer plants a field of might be responsible? (Hint: See p. 71.) corn and fertilizes it with a low-nitrogen fertilizer. Lesson 3.4 Lesson Assessment Visual Analogy The Biosphere 73