shervette uses and abuses lecture_final

shervette uses and abuses lecture_final - USES AND ABUSES...

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1 USES AND ABUSES USES AND ABUSES OF THE OCEAN OF THE OCEAN Chapt Chapt 15 15 Classifications of Marine Resources Classifications of Marine Resources Physical resources Marine energy resources Biological resources These resources can be further classified as renewable or non-renewable. The ocean’s resources are useful and convenient. Proper management is required so resources are not depleted. Salt and various minerals are mined in Salt and various minerals are mined in the sea: the sea: Magnesium Manganese nodules Manganese nodules Phosphorite Phosphorite (for fertilizers) (for fertilizers) Metallic sulfides and Metallic sulfides and muds muds Sodium chloride (table salt) Sodium chloride (table salt) Salt evaporation Salt evaporation ponds, Ecuador ponds, Ecuador Toxic Substances are commonly Toxic Substances are commonly released into the environment as a released into the environment as a consequence of mining, manufacture, transportation or use transportation or use Examples: Examples: Metals Metals Pesticides PCBs Petroleum Petroleum Point source pollution Point source pollution – a specific discharge location like a specific discharge location like drain pipes, ditches, sewer outfalls, smokestacks; drain pipes, ditches, sewer outfalls, smokestacks; Easy Easy to to identify blame when discovered ( identify blame when discovered ( “smoking gun smoking gun ”), and to ), and to monitor and regulate monitor and regulate Review: Review:
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2 Nonpoint source pollution - runoff such as from farm fields and feedlots, lawns and gardens, golf courses, roads, and construction sites; Spread over large areas (no specific location), so they are difficult to identify, monitor and regulate METALS • Effects of metals on marine organisms varies, but there is a strong correlation between high metal concentrations in sediments and declines in species diversity in benthic communities • Mercury – Neurological disorders (e.g. “mad-hatters” disease) – Minimata Bay, Japan disaster – Mercury in food fish is highest in top carnivores due to food web magnification •C a dm i um – Affects kidney function – Blue crabs • Lead – Neurological disorders – Found in high concentrations in marine sediments – Lead and other toxic metal levels are monitored in mussels Pesticides • Mostly man-made (synthetic) organic compounds – Microorganisms like bacteria don’t have enzyme systems to detoxify them, so they stick around a long time • Non-discriminatory and are toxic to most organisms • Sprayed in excess on land, so non-point runoff is inevitable • Amplified through trophic webs – see below • Have long half lives and therefore long-term negative effects on natural communities
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This document was uploaded on 11/01/2011 for the course MSCI 210 at South Carolina.

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shervette uses and abuses lecture_final - USES AND ABUSES...

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