Eutrophication. Pollution Effects on Society

Transcription

1 Eutrophication Pollution Effects on Society

2 Eutrophication What is eutrophication? Eutrophication is a natural process by which lakes and reservoirs become more productive as a result of increased nutrient concentrations, especially nitrogen (N) and phosphorus (P) with time Productivity here essentially refers to the net rate of photosynthesis The rate of productivity increase generally increases with time (100 yr.)

3 Eutrophication stages of eutrophication

4 Eutrophication phytoplankton (algae) Phytoplankton are defined as freefloating unicellular, filamentous, and colonial organisms that grow photoautotrophically in aquatic environments. Phytoplankton is the base of food chainsweb and directly provide food for zooplankton, fishes, and some aquatic animals. Phytoplankton responds quickly to environmental changes Phytoplankton abundance and diversity are widely used as biological indicators of still-water quality in lakes

5 Eutrophication phytoplankton (algae) Non point and point sources (N and P) N + P O 2 CO 2 Epilimnion Upper mixed layer H 2 O Photosynthesis Sugars and other organic molecules DO T N + P Hypolimnion Very slow/no mixed layer Sediment decomposition of dead biomass, bacteria, bentic macrofauna 5

6 Eutrophication phytoplankton (algae) Non point and point source sources (N and P) N + P H 2 O CO 2 Epilimnion Upper mixed layer O 2 Respiration Sugars and other organic molecules DO T N + P hypolimnion Aphotic zone Very slow/no mixed layer Sediment decomposition of dead biomass, bacteria, bentic macrofauna 6

7 Eutrophication Cultural Eutrophication Human activities that cause nutrient release, accelerate eutrophication sewage discharges storm sewer discharges chemical fertilizer livestock waste

8 Eutrophication So what s wrong with algae? Oxygen Depletion Decomposition of organic material in the sediment causes hypoxia on the bottom of water bodies Odor and taste problems Degrading of the aesthetic and recreational value of water bodies Lake Winnipeg (2010)

9 Eutrophication So what s wrong with algae? Some algae blooms are toxic Cyanobacteria harm aquatic biota, animals, and humans Symptoms: nausea, vomiting, abdominal cramps, diarrhea Severe cases include neurological symptoms: headache, dizziness, seizures, disorientation, memory loss, respiratory difficulty, coma

10 Eutrophication Cyanobacteria Aphanizomenon sp. July 13, 2011 Anabaena sp. 10

11 Eutrophication harmful algae Lake Taihu, China (2007) low water level and high temperature led to massive blue-green algae bloom 2 million residents in the City of Wuxi were without tap water for a week Lake Erie, USA (2014) cyanotoxins were detected in the tap water of Toledo, OH Lake Erie (2011) 500,000 residents were advised not to use tap water for three days Controlling phytoplankton bloom is a major challenge for the water quality management and water supply industry

12 Eutrophication How to prevent? Raise awareness of eutrophication. Eutrophication and its effects are not well understood by the public or policymakers. use cleaning agents and detergents that are biodegradable and that do not contain phosphates reduce the amount of nutrients that are causing an overgrowth of algae in lakes and streams More water treatment plants Higher standards for water quality Prevent illegal dumping find alternative ways to fertilize and control pests Implement regulations to mitigate nutrient losses, such as standards, technology requirements, or pollution caps for various sectors.