OPTION C.6 NITROGEN & PHOSPHORUS CYCLES

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1 OPTION C.6 NITROGEN & PHOSPHORUS CYCLES

2 C.6 B

3 IB BIO C.6 The phosphorus cycle describes the movement of phosphorus in an ecosystem. 3 It is a essential nutrient as it is needed to produce many molecules and structures. Examples include: DNA RNA ATP Phospholipids in the cell membrane

4 IB BIO C.6 4

5 IB BIO C.6 5 The weathering/erosion of rocks releases phosphates which are readily taken up by plants before entering the food chain. Marine sediments/mineral deposits contain the largest stocks.

6 IB BIO C.6 6 U4: can be added to the phosphorus cycle by application of fertilizer or removed by harvesting of crops. Like the nitrogen cycle, the phosphorus cycle can be affected by human activities. This is primarily observed in agriculture, where farmers use phosphate-based fertilizers.

7 IB BIO C.6 7 U4: can be added to the phosphorus cycle by application of fertilizer or removed by harvesting of crops. Phosphorous can be removed or added from the cycle by humans in two primary ways: Added - is mined to form fertilizer, which is transported and used in fields. Removed - is taken up and assimilated by plants. These are then harvested and carried away, remove phosphorus from the system.

8 IB BIO C.6 8 U5: The rate of turnover in the phosphorus cycle is much lower than the nitrogen cycle. A nutrient s turnover rate is the rate that amounts are moved from one stock to another The turnover rate of phosphorus is much lower than that of nitrogen. Turnover Rate Since phosphate is released through weathering, it is released slowly into ecosystems compared to nitrogen. Nitrogen, on the other hand, can be removed from the atmosphere.

9 IB BIO C.6 9 Skills S2: Assess the nutrient content of a soil sample. Soil sample kits are readily available at garden supply stores. These include chemicals that react with nutrients and change colour. Colors can be compared to included keys to study levels of nutrients.

10 IB BIO C.6 10 U6: Availability of phosphate may become limiting to agriculture in the future. The mining of phosphates for use in fertilizer is slowly depleting geological stocks. It is unknown when these will be depleted fully, but it is estimated to occur in the next years.

11 IB BIO C.6 11 U6: Availability of phosphate may become limiting to agriculture in the future. The future lack of availability of phosphate will limit fertilizer production. This will then affect yields in farmland production. This has the potential to result in famine as phosphates cannot be synthetically produced (unlike ammonia).

12 REVIEW IB BIO C Define the phosphorus cycle. 2. List three biological molecules that are synthesized using phosphorus. 3. Outline how human activities can add/remove phosphorus from the phosphorus cycle. 4. Define turnover rate. 5. Compare the turnover rate of nitrogen with that of phosphorus. 6. Outline the future availability of phosphorus and its affect on agricultural food production.

13 VIDEOS IB BIO C.6 CrashCourse: Nitrogen & s 13 Battling the Blook: Lake Eerie Phosphate Fertilizer