ENV200H1 Lecture Notes - Lecture 13: Water Cycle, Overfishing
17 Sep 2019
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Document Summary
The global ocean: covers 3/4 of earth"s surface, essential to hydrologic cycle, vast wilderness, no nation owns the open water, ocean is overused, tragedy of commons, used to believe dilution is the solution. Pollution & deteriorating habitat: pollution from land, runoff in rivers, atmospheric contaminants, the ocean is a dumping ground. Ocean dumping: several canadian cities dump sewage, plastics are a real, trash collects in certain areas, e. g. great pacific garbage patch, some estimate that 10% of all plastics end up in the ocean. Impacts on coral reefs: about 1/4 of all reefs at high risk, silt smothers reefs, overfishing, tourism, warming bleaching. Political considerations: offshore oil poses threats, remember the bp deepwater horizon oil spill in 2010. Climate change: rise in sea levels, could influence patterns of oceanic circulation, oceans expected to become more acidic, weakening of exoskeleton and shells. Case study: the arctic ocean and the northwest passage.
