Nutrient Input and Eutrophication 1

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Nutrient Input and Eutrophication 1

• Agricultural activities and sewage add nutrients,
  as well as disease organisms, to marine
  environments

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Nutrient Input and Eutrophication 2

• Agricultural activities and sewage add nutrients,
  as well as disease organisms, to marine
  environments
• Eutrophication is the addition of dissolved
  nutrients to a water body, resulting in large
  increases of phytoplankton production

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Nutrient Input and Eutrophication 3

• Eutrophication sources from land
• Point sources such as sewage treatment outfall
  pipes
• Point sources such as sewer overflows, which may
  be connected to sewage systems (Combined Sewer
  Outflows or CSOs)
• Commercial fertilizer used in agriculture - can
  be in runoff - non-point source

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Nutrient Input and Eutrophication 4

• Eutrophication sources from land
• Point sources such as sewage treatment outfall
  pipes
• Point sources such as sewer overflows, which may
  be connected to sewage systems (Combined Sewer
  Outflows or CSOs)
• Commercial fertilizer used in agriculture
• Animal waste in lagoons, connected to waterways

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Nutrient Input and Eutrophication 5
Rain water
Typical Urban Solution - When it rains, pollution
spills over into estuary
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Nutrient Input and Eutrophication 6

• Atmospheric sources
• Aerosols from agricultural fertilizer
• Nitrogen oxide deposited as nitrates on coastal
  ocean from fossil fuel emissions

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Nutrient Input and Eutrophication 7
Animal waste 4
Atmospheric nitrate 25
Atmospheric ammonium 14
Fertilizers 34
Point Sources 23
Contributions of nitrogen to Chesapeake Bay
watershed
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Nutrient Input and Eutrophication 8

• Effects of Eutrophication
• Development of Hypoxia
• Nutrients stimulate phytoplankton growth
• Not all phytoplankton is grazed
• Bacteria consume dead phytoplankton
• Oxygen declines
• If water is stratified or circulation is
  sluggish benthic animals die (or emigrate) owing
  to oxygen loss

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Development of hypoxia
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Nutrient Input and Eutrophication 9

• Treatment of Sewage
• Primary treatment - solids intercepted by screens
• Secondary treatment - more toxic nitrogenous
  compounds and colloids are stirred in aerobic
  tanks so that only phosphates, nitrates, ammonium
  released in coastal water
• Tertiary treatment - dissolved phosphates,
  nitrates, and ammonium removed (use of chemical
  techniques, microbial approaches to remove N
  compounds)

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Nutrient Input and Eutrophication 10

• Treatment of Sewage
• Objective of primary treatment to reduce organic
  material input, to reduce Biological oxygen
  demand (BOD)
• Primary treatment has been successful in the
  increase of dissolved oxygen in polluted water
  bodies such as New York Harbor

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Nutrient Input and Eutrophication 11
Oxygen Saturation
BOD Loadings from NYC (metric tons/day)
Relation of input of organic solids to oxygen in
water - NY Harbor