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Check In HW and Set Up 5 Yeast Dilutions

Check In HW and Set Up 5 Yeast Dilutions. Sentinel Species?. Warwick E. Kerr. Sentinels of Global Warming?. Biogeochemical Cycles. How do biogeochemical cycles reflect the 1 st law of thermodynamics?. Nutrient Cycles.

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Check In HW and Set Up 5 Yeast Dilutions

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  1. Check In HW and Set Up 5 Yeast Dilutions

  2. Sentinel Species?

  3. Warwick E. Kerr

  4. Sentinels of Global Warming?

  5. Biogeochemical Cycles

  6. How do biogeochemical cycles reflect the 1st law of thermodynamics?

  7. Nutrient Cycles • Materials necessary to build tissues and carry out essential life functions • Examples: Carbon, Phosphorus, Nitrogen

  8. HYDROLOGIC CYCLE • Evaporation • Condensation • Powered by solar radiation

  9. Primary Productivity v. Rainfall

  10. Carbon Cycle • Appx. 49,000 metric gigatons of carbon on Earth and in atmosphere • 71% in ocean • 22% fossilized • 3% in dead matter • 2% in live matter • 1% in atmosphere

  11. Mutualism & The Carbon Cycle • Photosynthesis “fixes” gaseous carbon (in form of CO2) into a more stable form (glucose/C6H12O6) • Cellular Respiration releases carbon in form of CO2

  12. A Precarious Balance • CO2 is only a small fragment of the atmosphere (0.04%) • Less than 2% of the world’s CO2 comes from burning fossil fuels • YET, the carbon cycle is rapidly becoming unbalanced in its ability to absorb the increases in CO2

  13. NITROGEN CYCLE • 78% of atmosphere is DIATOMIC NITROGEN (N2) • N2 is essentially useless to living organisms as the triple covalent bonds between nitrogen atoms make it chemically inert • To “liberate” nitrogen it must be chemically reacted with other atoms

  14. ABIOTIC NITROGEN FIXATION • High energy reactions like lightning and vulcanism can break the triple bonds of N2 • Liberated nitrogen reacts with oxygen to create Nitrate (NO3) and Nitrite (NO2)

  15. BIOTIC NITROGEN FIXATION • Rhizobium bacteria use the enzyme nitrogenase to break apart N2 in the absence of oxygen • To isolate themselves from oxygen, Rhizobium live in nodules on legumes

  16. Phosphorus & Algal Blooms • Excess phosphorus in aquatic ecosystems allows for algal populations to increase drastically by raising the carrying capacity • However, biological oxygen demand becomes too high and system crashes

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