Water Pollution and Eutrophication Pathogens Organic wastes Sediment Chemical pollutants Nutrients

In past ~ 40 yrs, reduction in: toxic discharges point sources of Phosphorus Still largely uncontrolled: sewage inputs of Nitrogen non-point source N & P

Eutrophication = nutrient over enrichment Phosphorusfreshwater Nitrogensalt & 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 O2O2

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 winterspring wind  mixing, all same temp  heating faster than mixing summer warm water less dense, floats, need lots of wind to mix

Summer stratification thermocline depth (m) temperature (C) 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 bloom August 2003

Microcystis A toxic blue-green alga

Microcystis bloom covers 600 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

Pathogens Disease 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 H 2 O, boil, or treat Wash hands frequently, don’t put them in your mouth after touching public surfaces of any kind

decomposition O2O2 Organic (biotic) waste

Sediment w. Erie, Sept Maumee River

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