Water Pollution and Eutrophication

Pathogens

Organic wastes

Sediment

Chemical pollutants

Nutrients

In past ~ 40 yrs, reduction in:

toxic dischargespoint sources of Phosphorus

Still largely uncontrolled:sewage inputs of Nitrogennon-point source N & P

Eutrophication = nutrient over enrichment

Phosphorus freshwater

Nitrogen salt & brackish

Limiting nutrient: The one in shortest supply relative to demand. If you add more of that nutrient the plants/algae will grow

Consequences

Dead zones

Harmful algal blooms

Coral death

Phytoplankton = floating algae, at base of foodweb

Limiting nutrient

Decomposing Phytoplankton consume oxygen

O2

Gulf coast dead zone

Fish and large animals swim away from poor water, small things die

May be responsible for sharks coming inshore near TX, shark bites high this summer

Lake Erie Dead Zone

Basics of lake stratification

ice

winter springwind

mixing, all same temp

heating faster than mixing

summerwarm water less dense, floats, need lots of wind to mix

Summer stratification

thermocline

dep

th (

m)

temperature (C)0 10 3020

0

10

30

20

region of rapid temp change

Lake Erie Dead zone

But…… point source controls of Phosphorus are in place.

Why would the central basin of Lake Erie be getting “over fertilized”?

What other conditions might contribute to the formation of a dead zone (it doesn’t happen every year)?

What might help stop dead zone formation?

What will happen if it isn’t stopped?

Harmful algal blooms in Oceans: Pfiesteria

Coast of Carolinas

Floating microrganisms that thrives in nutrient conditions

Highly toxic to fish and humans

Blue-green algae bloomBlue-green algae bloomAugust 2003August 2003

MicrocystisMicrocystisA toxic blue-green algaA toxic blue-green alga

Microcystis bloom coversMicrocystis bloom covers600 sq. km600 sq. km

Coral Reef overgrowth

Nutrients stimulate algae that cover coral\

Loose habitat and biodiversity

Loose economic benefits

Water Pollution and Eutrophication

Pathogens

Organic wastes

Sediment

Chemical pollutants

Nutrients

PathogensDisease causing bacteria, viruses and other parasites

Waste from an infected person or animal deposited in water that contacts another person

Cholera: common in US in 1800s, present in places with poor sewage treatment, can also be in food

Current outbreak in Senegal:

The first case diagnosed on October 11, 400 dead

Emergency water treatment now in place

Street merchants banned from selling water, fruit juice and other foods

It is the first cholera epidemic in Senegal since 1997.

Typhoid fever: common in developing world, vaccine available, contact with water, person or food

Giardia: common in US, carried by many animals (beaver fever), water (while swimming or drinking untreated, touching surface with microbe)

E. coli: common in US, water or food born, may not be toxic but indicates recent fecal contamination, causes beach closing locally (Maumee Bay and Put-in-Bay), can come from farms or people

Avoid Disease

Don’t drink untreated water: -camping, boil or treat w/ iodine or bleach-don’t drink lake water while swimming-traveling in developing world, bottled H2O, boil, or treat

Wash hands frequently, don’t put them in your mouth after touching public surfaces of any kind

decomposition

O2

Organic (biotic) waste

Sediment

w. Erie, Sept 18 2004

Maumee River

Silt filled spaces

Open spaces between gravel. Good spots for fish eggs and bugs