Oceanography exam 1 - Oceanography: Exam 1 Introduction...

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Oceanography: Exam 1 Introduction Oceanography: Ocean issues for the upcoming decades o Overpopulation Creates enormous demands for resources, food demand will double in 50 years, energy consumption will double in 40 years Near quintupling of grain harvest this century, industry and fertilizer (primarily nitrogen) Harvests not likely to get much more efficient o Affluence Hard to tell people to give up cars Recent economic declines have lessened our environmental impact o The Fragile and dangerous coastal zone 60% of worlds population resides within 100 km of the coastline Susceptible to storm damage o Overfishing Overexploitation, large animals taken, bycatch often very large, management focus on single species Fisheries Status: fisheries employ 200 million people and supply 19% of total animal protein consumed Yields leveling off in 1990s at 100 million tons Half of fish stocks fully exploited, 22% overexploited Removes 8% of total gross primary production Loss/alteration of habitat Loss of bio diversity, long lived animals strongly affected Shark population down 99% of north American easy coast. Rays and skates have increased sharply, they feed on mollusks. Scallop population has declined markedly Overfishing of sharks in Caribbean allows carnivorous fish to increase Increased predation on parrotfish and other algae eaters Allowed algae to dominate over corals o Pollution Eutrophication Excess input of nutrients We have doubled the amount of total N Toxic algal blooms Bioaccumulation of toxins PCBs, Hg First born dolphins in Sarasota bay almost always die
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Estimated 20,000 human made chemicals that were not present even 20 years ago o Ocean Hypoxia: “Dead Zones” Defined as a O2 < 2mL/L and stress to benthic organisms Excess nutrients stimulate plant growth, decay of plant tissue, depletes O2 Strong declines in fisheries, collapse of Norwegian lobster fishery Dead zones have doubled each decade since the 1960s 400 systems; over 245,000 km2, only 4% show signs of recovery Climate change an important factor – warming decreases o2 availability, warming increases rainfall and nutrient runoff, increase storm activity beneficial, 2005 storms aerated gulf of mexico Solution: keep fertilizers on land and or reduce use o Limiting resources Fuel and water Shrinking glaciers, declines in groundwater and climate change limiting availability of water Evidence suggest oil production peaked in 2006 Oil consumption expected to rise by 2020 Number of cars expected to increase from 0.7 to 1.2 billion by 2025 Recycling? o
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This note was uploaded on 02/02/2012 for the course ZOL 353 taught by Professor Idk during the Fall '11 term at Michigan State University.

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Oceanography exam 1 - Oceanography: Exam 1 Introduction...

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