Fig 5417 because mineral nitrogen can be transported

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Unformatted text preview: al nitrogen cycle. Fig. 54.17 Because mineral nitrogen can be transported in the air, “nitrogen deposition” is occurring all over the surface of the Earth Too Much of a Good Thing Negative effects of increased nutrient input include anaerobic "dead zones," harmful algal blooms, and eutrophication— the conversion of a water body to a (short-term) highly productive ecosystem with rapid decomposition, low oxygen levels, and rapid filling with decomposing organic matter. Taihu Lake, Wuxi, China Too Much of a Good Thing: Nitrate Runoff from Agricultural Fields Impacts Marine Communities Anaerobic "dead zones” such as those that occur in the Gulf of Mexico are one result. Nitrate input causes algal blooms; when algae die, decomposer populations get large and use up available oxygen in the water column, resulting in a dead zone. Eutrophication In 2011, the gulf dead zone was predicted to be the most extensive ever due to the flooding in the Mississippi drainage. Fortunately, Tropical Storm Don disrupted the area in late July. In 2012, the gulf dead zone was the fourth smallest on record due to the severe drought in the midwest and southern USA. The Carbon Cycle (2 of 4 Reservoirs) Elemental Composition Of Life Forms (by mass) 1 Gt= 1015g = billion metric tons Global Carbon Cycle net release 7.9 to atmosphere net 4.5 to land & ocean Limestone: 18,000,000 geological reservoir coal, oil, natural gas 5000 to 10000 •  diagram shows pools and fluxes •  Photosynthesis takes CO2 out of atmosphere; net uptake=P-R •  Respiration releases CO2 into atmosphere •  Net Flux from atmosphere to land/oceans is 4.5 Gt C /year •  Net Flux from land/oceans to atmosphere is 7.9 Gt C /year •  Thus, the atmospheric carbon pool is increasing. A general model of Carbon Cycling. Arrows indicate the processes that move carbon between 4 primary reservoirs. Most carbon is locked in mineral or fossil reservoirs (calcium carbonate, coal, oil, gas, peat) Photosynthesis & respiration are closely balanced Burning of fossil fuels is adding to atmospheric carbon Net addition to atmosphere each year = over 10 billion metric tons World Population Growth, Energy Transitions, and Urbanization The transition to fossil fuels, coal and oil, ushered in the industrial revolution and introduced a radically new type of so...
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This test prep was uploaded on 03/20/2014 for the course BIOLOGY 171 taught by Professor Hunter during the Fall '09 term at University of Michigan.

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