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Ecological Cycles

Ecological Cycles. Nitrogen, Carbon-Oxygen, Phosphorus, Sulfur. The Nitrogen cycle. The Nitrogen Cycle. Nitrogen is used by living organisms to produce a number of complex organic molecules like amino acids , proteins , and nucleic acids . 78% of the world’s atmosphere is nitrogen

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Ecological Cycles

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  1. Ecological Cycles Nitrogen, Carbon-Oxygen, Phosphorus, Sulfur

  2. The Nitrogen cycle

  3. The Nitrogen Cycle • Nitrogen is used by living organisms to produce a number of complex organic molecules like amino acids, proteins, and nucleic acids. • 78% of the world’s atmosphere is nitrogen • Despite its abundance in the atmosphere, nitrogen is often the most limiting nutrient for plant growth. This problem occurs because most plants can only take up nitrogen in two solid forms: ammonium ion (NH4+ ) and the ion nitrate (NO3- ) and CONNOT use raw atmospheric nitrogen

  4. Four processes participate in the cycling of nitrogen through the biosphere: • nitrogen fixation • atmospheric fixation by lightning • biological fixation by certain microbes • industrial fixation – making ammonia • decay (ammonification) – bacteria convert dead matter and wastes into ammonia • nitrification – bacteria convert ammonia into nitrates and nitrites • denitrification – bacteria return nitrogen to the atmosphere

  5. Human Influence on Nitrogen Cycle • artificial nitrogen fertilization • planting of nitrogen fixing crops • N2O has risen in the atmosphere as a result of agricultural fertilization, biomass burning, cattle and feedlots, and other industrial sources (N2O also destroys ozone) • eutrophication

  6. Water Cycle

  7. Water Cycle – Man’s Influence • Tropical Rain Forest – deforestation • Less trees = less tramsiration = less water in atmosphere = less rain • Olalla Reservoir • Huge groundwater store in central U.S. • Being depleted faster than replenished

  8. Carbon Cycle

  9. Carbon Cycle • O.03 carbon dioxide in atmosphere • Plants take in CO2 and release O2 in PHOTOSYNTHEIS • Animals take in O2 and release CO2 in CELLULAR RESPIRATION • Decay also release CO2 into the atmosphere

  10. Man’s Influence on Carbon Cycle • Burning fossil fuels releases CO2 into atmosphere • Cellulose in dead plant material is hard to breakdown (too big) • Accumulates undecomposed over time forming peat • Peat over time and under pressure forms fossil fuels • When fossil fuels are burned – releases carbon

  11. Sulfur Cycle • Sulfur • Component of proteins • Component of vitamins • Most sulfur is in rock and mineral slats • Released naturally into atmosphere from volcanoes and decomposition in wetlands • In atmosphere, SO2 reacts with water to produce sulfuric acid

  12. Man’s Influence • We release excess SO2 into the atmosphere by: • Burning fossil fuels • Refining petroleum products • Mining processes

  13. Chemosynthesis • Ocean vents in trenches • Bacteria use hydrogen sulfide H2S as energy source

  14. Phosphorus Cycle • Phosphorus important in • DNA molecules • ATP • Cell membranes • Bones • Teeth • shells

  15. Slow cycle • Not much in atmosphere – but in soil, rock, and water • Big water component

  16. Phosphorus Cycle

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