ICS 1 sem1 block 4 Biogeochemical cycles Packet Standards ES 7 a, b, c, d

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1 ICS 1 sem1 block 4 Biogeochemical cycles Packet Standards ES 7 a, b, c, d To be accepted for grading it must be in order and signed Period Name Print Sign Parent/Guardian: Print Sign Date 1. Cover Sheet / Agree-Disagree 2. WCW-warm-up, critical thinking, wrap-up 3. Standard ES 7 a, b, c, d 4. Vocabulary- Biogeochemical Cycles of Earth 5. Carbon Cycle Notes 6. Carbon Cycle Handout 7. Nitrogen cycle Notes 8. Nitrogen cycle Handout 9. Global Carbon Cycle Notes 10. Global Carbon Cycle Handout 11. Matter-Energy Notes 12. Matter-Energy Handout 13. Study-guides 14. CST-Practice-Questions Content Objective Students know the carbon cycle of photosynthesis and respiration and the nitrogen cycle. Students know the global carbon cycle: the different physical and chemical forms of carbon in the atmosphere, oceans, biomass, fossil fuels, and the movement of carbon among these reservoirs. Students know the movement of matter among reservoirs is driven by Earth s internal and external sources of energy. Students know the relative residence times and flow characteristics of carbon in and out of its different reservoirs. Language Objective Understand the proper use of the words, carbon dioxide, oxygen nitrogen, photosynthesis and respiration. Be able to explain the path of carbon through the world using key concepts such as calcification, bicarbonate s, greenhouse effect, and fixation. Explain the internal and external heat sources of the Earth which control energy movement, flow properties, and reservoir times. Explain the materials for, the creation process, and the storage of fossil fuels. Fossil fuels are the major source of energy for today, coal, gasoline, natural gas and oil are all fossil fuels. Be able to Describe the path of the carbon among these components and how this influences the environment.

2 WCW- #2 Warm-up 9/24 even 9/25 odd Describe the cycle in the picture Critical thinking When the amount of oxygen doubles, the amount of carbon dioxide Wrap-up Carbon enters the atmosphere by and leaves the atmosphere by. The two processes are related by Warm-up /27 even or 9/28 odd In the process of Photosynthesis, Sunlight +? + water/nutrients Creates oxygen +? Critical thinking How are decomposers and producers involved in the carbon and nitrogen cycles? Wrap-up Describe how nitrogen can be fixed and unfixed.

3 Warm-up 10/1 even 10/2 odd Critical thinking Describe the Relation between Fossil Fuel combustion, Tropical deforestation and global carbon cycle CO 2 sources Flux (Gt C/yr) Fossil fuel combustion 5.5 ± 0.5 Tropical deforestation 1.6 ± 1.0 Wrap-up From standard 7b bottom This release of has increased the concentration of dioxide in the atmosphere. dioxide is a primary g gas, and its concentration in the atmosphere is tied to climatic conditions. Warm-up 10/2 odd 10/3even Explain the cycle of Carbon through Photosynthesis and respiration in three steps. Critical thinking under warm-up Explain the heat provided by a meteor hitting the Earth. (i.e. explain how it adds heat) Use the pictures to help you You have it in the packet Example answer beginning 1 Ingredients 2 Process 3 Outcome Animal carbon dioxide oxygen sucrose Wrap-up Cell Respiration: An produces and consumes in its metabolism of food. is a typical food and a metabolic reaction can be represented by: C6H12O6 + 6O2 6 CO2 + 6 H2O

4 ES 7. Each element on Earth moves among reservoirs, which exist in the solid earth, in oceans, in the atmosphere, and within and among organisms as part of biogeochemical cycles. As a basis for understanding this concept: ES 7. a. Students know the carbon cycle of photosynthesis and respiration and the nitrogen cycle. Carbon and nitrogen move through biogeochemical cycles. The recycling of these components in the environment is crucial to the maintenance of life. Through photosynthesis, carbon is incorporated into the biosphere from the atmosphere. It is then released back into the atmosphere through respiration. Carbon dioxide in the atmosphere is dissolved and stored in the ocean as carbonate and bicarbonate ions, which organisms take in to make their shells. When these organisms die, their shells rain down to the ocean floor, where they may be dissolved if the water is not saturated in carbonate. Otherwise, the shells are deposited on the ocean floor and become incorporated into the sediment, eventually turning into a bed of carbonate rock, such as limestone. Uplifted limestone may dissolve in acidic rain to return carbon to the atmosphere as carbon dioxide, sending calcium ions back into the ocean where they will precipitate with carbon dioxide to form new carbonate material. Carbonate rocks may also be subducted, heated to high temperatures, and decomposed, returning carbon to the atmosphere as volcanic carbon dioxide gas. Carbon is also stored in the solid earth as graphite, methane gas, petroleum, or coal. Nitrogen, another element important to life, also cycles through the biosphere and environment. Nitrogen gas makes up most of the atmosphere, but elemental nitrogen is relatively inert, and multicellular plants and animals cannot use it directly. Nitrogen must be fixed, or converted to ammonia, by specialized bacteria. Other bacteria change ammonia to nitrite and then to nitrate, which plants can use as a nutrient. Eventually, decomposer bacteria return nitrogen to the atmosphere by reversing this process. ES 7. b. Students know the global carbon cycle: the different physical and chemical forms of carbon in the atmosphere, oceans, biomass, fossil fuels, and the movement of carbon among these reservoirs. The global carbon cycle extends across physical and biological Earth systems. Carbon is held temporarily in a number of reservoirs, such as in biomass, the atmosphere, oceans, and in fossil fuels. Carbon appears primarily as carbon dioxide in the atmosphere. In oceans carbon takes the form of dissolved carbon dioxide and of bicarbonate and carbonate ions. In the biosphere carbon takes the form of sugar and of many other organic molecules in living organisms. Some movement of carbon between reservoirs takes place through biological means, such as respiration and photosynthesis, or through physical means, such as those related to plate tectonics and the geologic cycle. Carbon fixed into the biosphere and then transformed into coal, oil, and gas deposits within the solid earth has in recent years been returning to the atmosphere through the burning of fossil fuels to generate energy. This release of carbon has increased the concentration of carbon dioxide in the atmosphere. Carbon dioxide is a primary greenhouse gas, and its concentration in the atmosphere is tied to climatic conditions. ES 7. c. Students know the movement of matter among reservoirs is driven by Earth s internal and external sources of energy. The energy to move carbon from one reservoir to another originates either from solar energy or as heat from Earth s interior. For example, the energy that plants use for photosynthesis comes directly from the Sun, and the heat that drives subduction comes from the solid earth. ES 7. D Students know the relative residence times and flow characteristics of carbon in and out of its different reservoirs. Carbon moves at different rates from one reservoir to another, measured by its residence time in any particular reservoir. For example, carbon may move quickly from the biomass to the atmosphere and back because its residence time in organisms is relatively short and the processes of photosynthesis and respiration are relatively fast. Carbon may move very slowly from a coal deposit or a fossil fuel to the atmosphere because its residence time in the coal bed is long and oxidation of coal by weathering processes is relatively slow.

5 Vocabulary item #4 1. Reservoirs container, holding area 2. Photosynthesis- process that uses sunlight, carbon dioxide water and nutrient sto make oxygen and glucose 3. Biosphere-specific region on Earth that harbors life 4. Respiration-breathing, oxygen in carbon dioxide out 5. Carbon dioxide- 6. Limestone- 7. Acid rain- 8. Subduction- 9. Fossil fuels- 10. Bacteria- 11. Biomass- 12. Sugar- 13. Greenhouse gas- 14. Matter- 15. Solar Energy- 16. Convection cells- 17. Residence times- 18. Atmosphere- 19. Oxidation- 20. Weathering-

6 Notes: item #5 Carbon Cycle of Photosynthesis & Respiration Photosynthesis -plants make food photo = light synthesis = putting together Plants take in carbon dioxide from the air water/nutrients from the soil in the presence of light energy and chlorophyll to produce sugar (glucose) and oxygen. Chlorophyll is the green pigment found in plants. Both chlorophyll and light energy need to be present for photosynthesis to take place, but they are not used up in the process. Some of the sugar produced during photosynthesis is used by the plant for its life processes (such as growing and reproducing ); the excess is converted mainly to starch and stored in various plant parts which may be used as food by animals and humans. Oxygen produced during photosynthesis replenishes the oxygen that was used up by living things during respiration This cycle of photosynthesis and respiration maintains the balance of carbon dioxide and oxygen on earth. carbon dioxide + water chlorophyll light energy sugar (glucose) + oxygen Photosynthesis Respiration Occurs in the presence of light (and chlorophyll in plant cells) Requires energy (light) to make sugar (glucose) Complex substances (sugar) are formed from simpler ones. Carbon dioxide and water are the raw materials Oxygen is given out. Occurs at all times in cells Releases energy from sugar Complex substances (sugar) are broken down into simpler ones. Carbon dioxide and water are the waste products. Oxygen is taken in.

7 Item 6 Carbon Cycle Worksheet Name Class 1.What inorganic molecule is carbon normally found in? 2.Name an organic molecule that carbon is found in. 3.What molecule do trees get their carbon from? 4.Where do primary consumers get their carbon from? 5.What process adds carbon to the atmosphere? 6.What process removes carbon from the atmosphere? 7.How does oxygen get into the water? 8.What do producers produce? 9.List 3 groups of producers? 10.What group eats producers? 11.How does carbon get back into the atmosphere from the food we eat? 12.Where do secondary consumers get their carbon from? 13.Where does an animal s or plant s carbon go when it dies? 14.Why should the amount of carbon in the atmosphere stay the same? 15.How is extra carbon getting into the atmosphere today? 16.List 3 ways that we could reduce the extra carbon that is getting into the atmosphere

8 17. In the space below, draw your own version of the carbon cycle. Use arrows to show which way the carbon is going. Label - Producers, Primary Consumers, Secondary Consumers CARBON CYCLE

9 Notes: Nitrogen item #7 Nitrogen (N) All need nitrogen to survive Huge amounts in the atmosphere, but most animals and plants can t get it It needs to be fixed i.e. put into useful compound Then it can move through the cycles and organisms in an ecosystem Where Can You Find It? Main sources of nitrogen atmosphere The other source of nitrogen is in the nitrates of soil. Nitrogen can be converted into useful nitrate compounds by bacteria, algae, and even lightning. Once in the soil, the nitrogen becomes biologically accessible Borrowing Nitrogen Plants are the main users of nitrogen in the soil. They are able to take in the nitrates through their root system. Once inside the plant, the nitrates are used in organic compound that let the plant survive. Organic compounds have carbon atoms. Compounds might be proteins, enzymes, or nucleic acids Herbivores convert amino acids into new proteins. Nitrogen atoms are returned to the soil in feces and Decaying matter

10 Item # 8 Nitrogen Cycle Worksheet Name Class 1. Why do plants and animals need nitrogen (N)? 2. What molecule in the atmosphere is nitrogen normally found in? 3. What molecule in the ground is nitrogen found when there is no oxygen around? 4. What molecule in the ground is nitrogen found when there is oxygen around? 5. What organic molecule is nitrogen found in? 6. What are 2 ways that atmospheric nitrogen gets into the ground? 7. What organisms (living things) do the nitrogen fixation for plants? 8. Why don t farmers have to put nitrogen fertilizer on soybeans? 9. Where do plants get their nitrogen from? 10. How do primary consumers get their nitrogen from? 11. How do secondary consumers get their nitrogen from? 12. What s another term for a primary consumer? 13. What s another term for a secondary consumer? 14. Where does an animal s or plant s nitrogen go when it dies? 15 Who breaks the dead organisms body back into inorganic nitrogen? In the space below, draw your own version of the nitrogen cycle. Use arrows to show which way the nitrogen is going.

11 Label Producers(Plants), Nitrogen Fixing Bacteria, Primary Consumers, Secondary Consumers, Decomposers NITROGEN CYCLE

12 Item # 9 The Global Carbon Cycle More than any other element, carbon is associated with our changing climate. Where does carbon reside? What trends in atmospheric CO 2 have been observed? What regulates the flow of carbon between its various reservoirs? Is it possible that feedback mechanisms regulate the amount of atmospheric CO 2?

13 How is carbon cycled at a global scale? Cell Respiration: An animal produces carbon dioxide and consumes oxygen in its metabolism of food. Glucose is a typical food and a metabolic reaction can be represented by: C 6 H 12 O 6 + 6O 2 6 CO H 2 O Photosynthesis: A plant and green bacteria, on the other hand, produces oxygen and consumes carbon dioxide. Energy in the form of electromagnetic radiation (or photons) is supplied so that the lowenergy-content carbon dioxide can be converted to high-energy-content glucose. An overall reaction for the complicated multi-step photosynthesis reaction can be represented by: 6CO H 2 O C 6 H 12 O 6 + 6O 2 + 6H 2 O

14 Item # 10 Global Carbon Cycle 1. If 100 kg of carbon dioxide is photosynthesized, does this contribute to the amount of free oxygen (O or O 2 ) in the atmosphere or deduct from it? How much oxygen is produced or destroyed? How much carbon is produced or destroyed? Photosynthesis generates free oxygen. The atomic weight of CO 2 is 44 with 12 AMU from Carbon and 32 AMU from Oxygen. If 100 kg of CO 2 is photosynthesized, 72.7 kg of free oxygen (2 atoms for every one molecule of CO 2 ) is produced and 27.3 kg of Carbon (in the form of carbohydrates) is produced. (The carbohydrates would weight kg.) The reaction for photosynthesis is: CO 2 + H 2 O + hv --> CH 2 O + O 2 2. During the early evolution of the earth, what was an important source of free oxygen? Did it eventually help sustain a new processes of oxygen production? What was that new process? Free oxygen may have been created by photodissociation of water vapor in the early Earth. This created free oxygen and eventually ozone which enabled plantlife and photosynthesis to exist on land. It is probably that photosynthesis already existed in the oceans before the ozone layer. 3. If under global warming, the amount of photosynthesis decreases (due to reduced extent of boreal forests) from 200 Gt-O/yr to 100 Gt-O/yr, how long will the oxygen in the atmosphere last? In steady state, photosynthesis and respiration are in balance. If photosynthesis were to decrease by 50%, this represents a net sink of 100 Gt-O/yr. Given that the reservoir is 1.1x106 Gt. Oxygen would last 1.1x106/100 years or about 10,000 years. 4. Identify at least one rapid process not mentioned in class that may constrain the amount of atmospheric oxygen between certain minimum and maximum bounds. Fire may help constrain the levels of atmospheric oxygen. If oxygen levels become too high, fires will burn stronger and longer thus depleting atmospheric O2. If oxygen levels decrease, fewer fires will occur and they will not burn as strongly. It is believed that this has helped constrain levels of oxygen in recent millenia to between roughly 10% and 30%. 5. Why is the amount of "free" oxygen in the atmosphere related to the amount of carbon in the atmosphere? If one increases the amount of carbon in the atmosphere does this increase or decrease the amount of "free" oxygen? Carbon in the atmosphere is precominantly found in CO 2. If carbon reacts (to form sediments for example) this releases free oxygen in the atmosphere. If carbon reacts to re-enter the atmosphere (through respiration for example) this removes oxygen from the atmosphere. If one were to increase the amount of carbon in the atmosphere, this would decrease the amount of free oxygen.

15 1. Estimate the time scale for emptying the sedimentary reservoir by geologic processes given that volcanic outgassing amounts to about 0.05 Gt C/yr and the reservoir is contains roughly 60 million Gt-C. Volcanic outgassing is a process that depletes sedimentary carbon and would deplete a reservoir of 60 million Gt in about 1.2 billion years. 2. If the oceans were to stop absorbing carbon (due to saturation for example), what percentage increase in atmospheric carbon (per year) would initially occur? The oceans absorb about 50 GtC per year. If this were to stop, the atmosphere would gain 50 GtC per year which is about 6.7% of the 750 GtC held by the atmosphere. If you tried to use the numbers from Table it would be incorrect because that Table shows the net imbalance between dissolution and evaporation of carbon, not the net dissolution. 3. What carbon compounds are produced by photosynthesis and exploited by living beings for energy? What reactants are required to generate these compounds? Carbohydrates (C-H 2 O) and oxygen are produced by photosynthesis from the reactants of CO 2, H 2 O and light. 4. If the deep ocean circulation were to accelerate and thus increase the existing exchange of carbon with surface oceans, what impact might this have on the surface ocean and, eventually, the atmosphere? In the net, the exchange of carbon between the deep ocean and the surface ocean contributes bicarbonate ions to the surface ocean. If upwelling were to increase the surface ocean would have more bicarbonate ion and would eventually saturate, reducting the amount of CO 2 that would disolve in the upper ocean and atmospheric carbon levels would eventually increase. 5. Propose an investigation aimed at reducing the amount of carbon dioxide in the atmosphere based on what you know about the long-term or short-term carbon cycles. To do so, simply state a process relevant to atmospheric CO 2 levels and suggest an hypothesis you'd like to investigate for modulating its rate. There are many possible answers to this. For example, one might attempt to modulate the rate of carbon uptake by the surface oceans by enhancing photosynthesis in the surface oceans. Currently, experiments that contribute iron to the upper ocean are exploring this possibility. Many other experiements can be envisioned.

16 Notes matter energy item#11 The movement of matter among reservoirs is driven by Earth s internal and external sources of energy The energy to move carbon from one reservoir to another originates either from Internal sources of energy Heat in the Earth 1 source Remnants of heat from impacts with planetesimals early in Earth's history. Impacts with large bodies such as these (including the impact which led to the formation of the moon) trapped the thermal energy of the collision in the surrounding rock of the planet, and may have been enough in certain circumstances to completely melt the early Earth. 2 source remnant of an early Earth event known as the Iron Catastrophe. With much of early Earth still molten, denser metals, particularly iron and nickel, migrated to the center of the planet. Tremendous amounts of frictional heat was created, enough to completely melt the planet once again. 3 source from compression due to gravity. 4 source the decay of radioactive elements. This source of heat is gradually declining due the decreasing amounts of radioactive isotopes, the decrease being caused by the decay. Ex Driving force of subduction External sources of energy Solar Radiation The driving force of weather on Earth. In the "water cycle", the sun is responsible for evaporation of ocean surface water. As this happens, the water vapor rises. The combination of the Earth's rotation and the changes in atmospheric pressure is the primary determinant for when and where the rain comes down. Ex Driving Force of photosynthesis by its residence time in any particular reservoir. Example Carbon may move quickly from the biomass to the atmosphere and back because its residence time in organisms is relatively short and the processes of photosynthesis and respiration are relatively fast. The relative residence times and flow characteri stics of carbon in and out of its different reservoirs Carbon moves at different rates from one reservoir to another, measured Carbon may move very slowly from a coal deposit or a fossil fuel to the atmosphere because its residence time in the coal bed is long and oxidation of coal by weathering processes is relatively slow.

17 1. V = d/t speed equals distance divided by time Suppose the Speed of a molecule is 10% the speed of light or 30,000,000 meters per second. What is the time it took to travel 1,000,000 m?

18 Item # 12 Matter energy Handout Atmosphere 78% ammonia proteins denitrification Nitrate nitrogen-fixing plants animal s waste plants 1. Our atmosphere is nitrogen gas. 2. Animals and plants cannot directly use all the nitrogen found in our. 3. Only special bacteria can directly use nitrogen in our atmosphere and fix it so other organisms can benefit. These bacteria are called - bacteria. 4. Higher organisms use nitrogen to make their. 5. Animal waste decay by the action of bacteria which create and products rich in nitrogen, and useful for plants to use again. 6. bacteria in the soil can break down the ammonia into the gaseous form of nitrogen, which is not available for use by plants or animals. 7. In another part of the cycle, animals eat containing nitrogen, which is again returned to the soil by animal or decaying and. 8. Draw a diagram of the Nitrogen cycle using the words in the text box. Oxygen Cycle Photosynthesis Ozone Waste Crust Oceans Respiration 1. Plants release billion tons of oxygen during process of. 2. Atmospheric oxygen in the form of provides protection from harmful ultraviolet rays. 3. Oxygen is found everywhere on Earth, from Earth s (rocks) to the where it is dissolved. 4. Oxygen is vital for by animals, a process which produces CO 2.and water. 5. Oxygen is also necessary for the decomposition of into other elements necessary for life. 6. Write the equation for respiration. 7. Draw a diagram of the Oxygen Cycle using the words in the text box.

19 Item # 13 is only on website 1. Carbon is essential to life because A. It s the most common element. B. It is the molecule around which all the molecules of life are built. 2. Where do plants gets their supply of carbon? A. Cellular Respiration B. Photosynthesis 3. Where does the carbon for your body come from? A. From eating plants and animals B. From breathing it in 4. Where does the oxygen for your body come from? A. From eating plants and animals B. Photosynthesis in plants 5. Which of the following does not use up oxygen and produce carbon dioxide? A. Cellular Respiration B. Photosynthesis 6. Nitrogen is essential to life because A. It is needed for building proteins (growth) B. It is breathed in by all life. 7. Plants get nitrogen from A. Breathing it in B. Absorbing it through roots from the ground 8. Nitrogen-fixing bacteria are important because A. They turn nitrogen from the air into nitrogen compounds in the soil. B. They are essential for plants being able to carry out photosynthesis. 9. During decomposition, A. Bacteria use oxygen to produce nitrates from ammonium. B. Bacteria produce the oxygen needed for photosynthesis. 10. Excess nitrates in water causes problems for the Chesapeake Bay because A. They cause excessive cellular respiration in plants and animals, resulting in a large amount of carbon dioxide production. B. They cause excessive algae growth, blocking sunlight and reducing oxygen when it dies.

20 Carbon Cycle (2 points each) Use the following word bank to answer a) CELLULAR RESPIRATION b) GLUCOSE (CARBOHYDRATES) c) EATING PLANTS d) CO What inorganic molecule is carbon normally found in? 12. Name an organic molecule that carbon is found in. 13. What process adds carbon to the atmosphere? 14. Where do primary consumers get their carbon from? Use the following word bank to answer a) GROUND b) PHOTSYNTHESIS AND RESPIRATION SHOULD BALANCE EACH OTHER OUT. c) CELLULAR RESPRATION d) PRIMARY CONSUMERS 15. How does carbon get back into the atmosphere from the food we eat? 16. Where do secondary consumers get their carbon from? 17. Where does an animal s or plant s carbon go when it dies? 18. Why should the amount of carbon in the atmosphere stay the same?

21 Use the following word bank to answer Nitrogen Cycle (2 points each) a) AMMONIA (NH 3) b) TO BUILD PROTEIN MOLECULES c) NO 3 d) N Why do plants and animals need nitrogen (N)? 20. What molecule in the atmosphere is nitrogen normally found in? 21. What molecule in the ground is nitrogen found when there is no oxygen around? 22. What molecule in the ground is nitrogen found when there is oxygen around? Use the following word bank to answer a) HERBIVORE b) EATING ANIMAL PROTEIN c) EATING PLANT PROTEIN d) THE GROUND (NO 3 ) 23. Where do plants get their nitrogen from? 24. How do primary consumers get their nitrogen from? 25. How do secondary consumers get their nitrogen from? 26. What s another term for a primary consumer?

22 Item #14 CST prep Carbon / Nitrogen Cycles Quiz 1. Carbon is essential to life because A. It s the most common element. B. It is the molecule around which all the molecules of life are built. C. It is found in inorganic molecules. D. Plants can t live without it. 2. Where do plants gets their supply of carbon? A. Cellular Respiration B. From the ground C. From the waste of animals D. Photosynthesis 3. Where does the carbon for your body come from? A. Cellular Respiration B. From breathing it in C. From eating plants and animals D. Photosynthesis 4. Where does the oxygen for your body come from? A. Cellular Respiration B. From the ground C. From eating plants and animals D. Photosynthesis in plants 5. Which of the following does not use up oxygen and produce carbon dioxide? A. Cellular Respiration B. Photosynthesis C. Decomposition D. Burning fossil fuels like coal and oil 6. Nitrogen is essential to life because

23 A. It is the most common element. B. It is the molecule around which all the molecules of life are built. C. It is breathed in by all life. D. It is needed for building proteins (growth) 7. Plants get nitrogen from A. Breathing it in B. Absorbing it through roots from the ground C. Basic photosynthesis D. Cellular Respiration 8. Nitrogen-fixing bacteria are important because A. They turn nitrogen from the air into nitrogen compounds in the soil. B. They are essential for plants being able to carry out photosynthesis. C. They break up dead plants and animals in the soil. D. They release excess nitrogen from the soil into the atmosphere. 9. During decomposition, A. Bacteria use oxygen to produce nitrates from ammonium. B. Bacteria produce the oxygen needed for photosynthesis. C. Bacteria put oxygen back into the atmosphere. D. Bacteria use oxygen to produce ammonium from dead material. 10. Excess nitrates in water cause problems for the Chesapeake Bay because A. They cause excessive cellular respiration in plants and animals, resulting in a large amount of carbon dioxide production. B. They cause excessive bacteria growth resulting in too much oxygen which hurts photosynthesis in plants. C. They cause excessive algae growth, blocking sunlight and reducing oxygen when it dies. D. Nitrates are poisonous to fish, crabs, and oysters.