1. Eutrophication & Management
Topic 8
A.S: K – N
REMEMBER TO STUDY FOR THE QUIZZY
S.D. A-J ON TUESDAY AFTER BREAK!!!

2. Eutrophication
The addition of excess nutrients (phosphates and nitrates) to a body of water…..can be natural, but is usually accelerated by humans (Anthropogenic).

3. Anthropogenic phosphates & nitrates
Agriculture sources:
Fertilizer
Animal Waste/Manure
Non-agriculture sources:
Detergents
Industrial effluent
Sewage
Are most of these point source or non-point source pollutants?

4. Process of Eutrophication
Run-off including phosphates and nitrates enter body of water.
Algae begin to quickly grow.
Algal bloom forms (mats of algae)
What does this cause?
Aquatic Plant Death (not enough light)
Because there are now less plants (macrophytes):
What 2 things will this cause?
Bacteria pop increase/increased turbidity
Describe the feedback going on here:

6. A Second Positive Feedback
As the animals, plants, and algae die, what happens to BOD and Why?
~ BOD goes up (increases) b/c of bacteria pop increase
So what is happening to even more of the oxygen in the water?
Decreases
Now describe another feedback:

7. Macrophytes decrease

8. Turbid Water
Fish Kill

9. Death of the lake or “Dead Zones”
At some point there is not enough oxygen to support aquatic life. This can cause a collapse of the food chain and decreased diversity.
This increases the sediments in the bottom of the lake as it settles.

10. Local Example… The Chesapeake Bay

11. The Watershed Over 64,000 square miles
Incorporates 6 states: DE, MD, NY, PA, WV, VA, and Washington D.C.
~16 million people live in the watershed
Over 100,000 streams, creeks, and rivers flow into the bay

12. A Quick History of the Bay
The first explorers reached the Bay in the 1500s
By 1650, land around the watershed was being cleared for agriculture and timber production.
As early as 1750, some ports became unnavigable due to increased sediment
By the end of the nineteenth century, 60% of watershed forests had been cleared.

13. State of the Bay
Over Half of the forested lands surrounding the bay have been cleared.
Over half of the wetlands are gone.
90% of underwater grasses are gone.
98% of the Bay’s oyster population is gone.
They used to filter entire volume of the Bay in 3 to 6 days….now it takes about a year!
Chesapeake Bay Foundation gives a State of the Bay ranking every 2 years:
Lowest in 1983 of 23/100 when the first CB Agreement was signed
Has been steadily increasing to a 34/100 in 2016 (C-)

15. 2016 State of the Bay = 34 C-

16. Pollution Management – Altering Human Activities:
Using alternative detergents with no phosphates
Using crops that need less fertilizer or rotational planting/grazing.
Use of cover crops in off season.
What will this do?
Planting riparian buffers =
Vegetated area to protect water quality.
Education through PSA’s

18. Pollution Management – Regulate
Governmental control on the amount of development
Harvesting Regulations:
MD and VA have harvesting regulations (size, sex and amount of crabs and oysters)
Clean Water Act
Regulations on sewage treatment facilities to better remove phosphates from effluent.
Restrictions on fertilizer use (difficult to control)

19. Pollution Management – Restoration
Dredging sediments and algae out
Pumping oxygen into body of water (small fountains can help with this).
Construction of oyster reefs
Since 1997, CBF has transplanted 7 million oysters; plan to produce 31 million in the next 10 years.
Submerged Aquatic Vegetation (SAV) planting.