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Eutrophication. Eutrophication : the natural nutrient enrichment of a shallow lake, estuary or slow moving stream, mostly from runoff of plant nutrients from the surrounding land.
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Eutrophication • Eutrophication: the natural nutrient enrichment of a shallow lake, estuary or slow moving stream, mostly from runoff of plant nutrients from the surrounding land. • Cultural eutrophication: human activities accelerate the input of plant nutrients (mostly nitrate- and phosphate-containing effluents) to a lake. • 85% of large lakes near major population centers in the U.S. have some degree of cultural eutrophication.
Eutrophication Relation to Pollution • Gets into our water supply from runoff, etc. • Not normally in the water Considered to be pollution
Cause/Effect • CAUSE: Fertilizers, erosion, sewage, etc. get into water and the effect is high photosynthetic productivity. • EFFECT: Water is cloudy because of the algae and cyanobacteria that are supported by the nutrients.
Environmental Justice • “The fair treatment and meaningful involvement of all people regardless of race, color, national origin, or in income with respect to the development, implementation, and enforcement of environmental laws, regulations and policies.” • EPA (Environmental Protection Agency)
POLLUTION OF FRESHWATER STREAMS • Flowing streams can recover from a moderate level of degradable water pollutants if they are not overloaded and their flows are not reduced. • In a flowing stream, the breakdown of degradable wastes by bacteria depletes DO and creates an oxygen sag curve. • This reduces or eliminates populations of organisms with high oxygen requirements.
Normal clean water organisms (Trout, perch, bass, mayfly, stonefly) Trash fish (carp, gar, leeches) Fish absent, fungi, sludge worms, bacteria (anaerobic) Trash fish (carp, gar, leeches) Clean Normal clean water organisms (Trout, perch, bass, mayfly, stonefly) Types of organisms 8 ppm Dissolved oxygen (ppm) 8 ppm Clean Zone Recovery Zone Septic Zone Decomposition Zone Clean Zone
POLLUTION OF FRESHWATER STREAMS • Most developed countries have sharply reduced point-source pollution but toxic chemicals and pollution from nonpoint sources are still a problem. • Stream pollution from discharges of untreated sewage and industrial wastes is a major problem in developing countries.
Global Outlook: Stream Pollution in Developing Countries • Water in many of central China's rivers are greenish black from uncontrolled pollution by thousands of factories.
Case Study: India’s Ganges River: Religion, Poverty, and Health • Religious beliefs, cultural traditions, poverty, and a large population interact to cause severe pollution of the Ganges River in India. • Very little of the sewage is treated. • Hindu believe in cremating the dead to free the soul and throwing the ashes in the holy Ganges. • Some are too poor to afford the wood to fully cremate. • Decomposing bodies promote disease and depletes DO.
Case Study: India’s Ganges River: Religion, Poverty, and Health • Daily, more than 1 million Hindus in India bathe, drink from, or carry out religious ceremonies in the highly polluted Ganges River.
POLLUTION OF FRESHWATER LAKES • Dilution of pollutants in lakes is less effective than in most streams because most lake water is not mixed well and has little flow. • Lakes and reservoirs are often stratified (layers!)and undergo little mixing. • Low flow makes them susceptible to runoff. • Various human activities can overload lakes with plant nutrients, which decrease DO and kill some aquatic species Eutrophication!
POLLUTION OF GROUNDWATER • Can take hundreds to thousands of years for contaminated groundwater to cleanse itself of degradable waste • Non-degradable wastes: • Lead, arsenic, fluoride • Present in water permanently • Slowly degradable wastes: • DDT • Present for decades
POLLUTION OF GROUNDWATER • Leaks from a number of sources have contaminated groundwater in parts of the world. • According the the EPA, one or more organic chemicals contaminate about 45% of municipal groundwater supplies. • By 2003, the EPA had completed the cleanup of 297,000 of 436,000 underground tanks leaking gasoline, diesel fuel, home heating oil, or toxic solvents.
Case Study: Arsenic in Groundwater - a Natural Threat • Toxic Arsenic (As) can naturally occur at high levels in soil and rocks. • Drilling into aquifers can release As into drinking water supplies. • According to WHO, more than 112 million people are drinking water with As levels 5-100 times the 10 ppb standard. • Mostly in Bangladesh, China, and West Bengal, India.
Marine Ecology Importance of the Ocean Environment
Area • Saltwater covers about 71% of the earth’s surface Life: There are 250,000 known species of marine plants and animals, many are food for other organisms, like us.
Temperature • Solar heat is distributed by ocean currents & as ocean water evaporates. • The oceans are major players in the earth’s climate & are a gigantic reservoir for carbon dioxide (storage) • Help regulate the temperature of the troposphere (where all weather takes place!)
Estuary Where fresh water and salt water meet Coastal body of water, partly surrounded by land, with access to the open ocean and a large supply of fresh water from a river
Salinity • Total amounts of dissolved salts • Salinity fluctuates with tidal cycles, the time of year, & precipitation. • The organisms that live here must be able to tolerate these conditions
Fertility of Estuaries • Estuaries are the most fertile ecosystems in the world • Greater productivity than either the adjacent ocean or the fresh water upriver
Reasons for High Fertility • Nutrients are transported from the land into rivers that flow into the estuary • Tidal action circulates nutrients and helps remove wastes • A high level of light due to shallow water • Many plants provide an extensive photosynthetic carpet
Difficulties-Sandy Beach • Shifting environment that threatens to engulf them & no protection against wave action. • Most animals bury into the sand. They move with the tides, so they’re always underwater & don’t dry out.
Difficulties-Rocky Shore • High wave action at high tide; drying out & temperature changes during low. • Animals have a way of sealing in moisture like a shell & cling to the rocks so they don’t get washed away with waves.
