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

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

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?

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:

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:

Macrophytes decrease

Turbid Water Fish Kill

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.

Local Example… The Chesapeake Bay

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

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.

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-)

2016 State of the Bay = 34 C-

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

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)

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.