Chemical/Nutrient Recycling in Ecosystems

1. Chemical/Nutrient Recycling in Ecosystems 1

2. DO Now 1.In addition to energy, what do organisms need to survive?

3. Anything that has mass and takes up space Matter is recycled in ecosystems What is matter composed of? Matter

4. Levels of organization in the biosphere

5. Levels of organization in the biosphere

6. Elements in Living Things The elements found in significant amounts in organisms are Carbon Hydrogen Oxygen Nitrogen “HONC” HONC if you love science! Also phosphorus and sulfur “HONC-PS”

7. Law of Conservation of Mass Matter is neither created nor destroyed! So what happens when matter seems to just “appear” or “disappear”?

8. What happens to matter in the biosphere? Matter is recycled by naturally occurring chemical reactions!

9. What four elements primarily make up living organisms? Hydrogen, Oxygen, Nitrogen, Carbon • These elements (along with others such as _sulfur__ and _phosphorus_ are the basis of life’s most important compounds:water, carbohydrates, lipids, nucleic acids and proteins

10. CYCLES OF MATTER • In other words, a handful of elements combine to form the building blocks of all known organisms. • However, organisms cannot manufacture these elements and do not “use them up”. • Where these essential elements come from?

11. CYCLES OF MATTER Unlike the one-way flow of energy, matter is recycled within and between ecosystems

12. BIOGEOCHEMICAL CYCLE • Process in which elements, matter is passed from one organism to another. • As matter moves through these cycles, it is transformed which means that it is never created or destroyed, just changed.

13. The Water Cycle

14. The Carbon and Oxygen CyclesThe pathway of carbon and oxygen through an ecosystem

15. The Carbon and Oxygen Cycles 1. Almost all oxygen in Earth’s atmosphere originally came from the photosynthetic activities of plants 2. How do C and O cycle through the biosphere? 2 processes – PHOTOSYNTHESIS AND CELLULAR RESPIRATION

16. The Carbon and Oxygen Cycles

17. Carbon Cycle • How have humans affected the carbon cycle? • What processes are putting too much carbon dioxide into the atmosphere? • What problem does this lead to?

18. The Nitrogen CycleThe pathway of nitrogen through an ecosystem 18

19. Nitrogen is an important element in living things Used to make proteins and nucleic acids! Nitrogen gas (N2) makes up 78% of the earth’s atmosphere However…most organisms cannot use N2 directly Why can’t organisms use N2 directly?

20. How do plants get nitrogen? • Rely on Nitrogen Fixing Bacteria! • These bacteria live in the roots of some plants (legumes – peas, peanuts, beans) and in the soil • These nitrogen fixing bacteria are the only organisms that can “fix” atmospheric nitrogen into a usable form (ammonia)

21. Plants and Nitrogen Compounds So, nitrogen is obtained by plants either directly from the bacteria in their roots, or in the soil Some nitrogen in the soil also comes from decaying matter – decomposers break down waste and dead organisms into usable forms of nitrogen

22. What are the usable forms of nitrogen? • Most plants usenitrogen in two inorganic forms to make proteins • NH3 (ammonia) and NO3- (nitrate)

23. Animals must eat plants to meet their nitrogen needs So, what organisms are absolutely necessary for the nitrogen cycle to continue? BACTERIA!!

24. How does nitrogen get back into the atmosphere? Other bacteria convert nitrates back into nitrogen gas. This process is called DENITRIFICATION.

25. Atmospheric nitrogen fixation – a relatively small amount of nitrogen gas is converted into usable forms by lightning

26. The Nitrogen Cycle

27. The Phosphorus Cycle • Movement of phosphorus from environment to organisms and back to environment • P is needed to form bones and teeth in animals • P is needed to form nucleic acids

28. How do plans and animals get phosphorus? • Plants get it from soil and water • Animals get it by eating plants or other animals that have eaten plants • Slow cycle, does not usually involve atmosphere

29. How does P enter soil? • When rocks erode, a little P dissolves as phosphates in soil and water • P added to soil and water when excess p is excreted in waste from organisms and when organisms die and decompose

30. How do plants and animals get phosphorus? • Plants absorb phosphates in the soil through their roots • Animals eat plants • Some p washes off land and ends up in oceans • Many phosphate salts not soluble in water, so they sink to bottom of ocean and accumulate as sediment

31. How do humans affect phosphorus and nitrogen cycles? • Fertilizer use!