Title: Nutrient Input and Eutrophication 1
1Nutrient Input and Eutrophication 1
- Agricultural activities and sewage add nutrients,
as well as disease organisms, to marine
environments
2Nutrient 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
3Nutrient 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 -
4Nutrient 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
-
5Nutrient Input and Eutrophication 5
Rain water
Typical Urban Solution - When it rains, pollution
spills over into estuary
6Nutrient Input and Eutrophication 6
- Atmospheric sources
- Aerosols from agricultural fertilizer
- Nitrogen oxide deposited as nitrates on coastal
ocean from fossil fuel emissions
7Nutrient 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
8Nutrient 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
9Development of hypoxia
10Nutrient 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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12Nutrient 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
13Nutrient 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