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Threats to Aquatic Environments - Dams, Freshwater Diversion And Use, Water Pollution Poses A Threat, Sediment—good And Bad, Air Pollution Affects Water Quality

According to the U.S. Geological Survey in "How Much Water Is There on (and in) the Earth?" (http://ga.water.usgs.gov/edu/earthhowmuch.html), about 326 million trillion gallons of water make up the total water supply of the planet. This provides an enormous aquatic habitat for a wide variety and number of animal and plant species. The aquatic environment is threatened by many human activities around the world. Humans consume vast amounts of freshwater and exert control over water flows in many rivers and streams. Land development, agricultural practices, industrialization, and commercial fishing have all affected the aquatic environment in some way.

Additional Topics

Threats to Aquatic Environments - Dams

Dams have affected rivers, the lands abutting them, the water bodies they join, and aquatic wildlife throughout the United States. Water flow is reduced or stopped altogether downstream of dams, altering aquatic habitats and drying wetlands. Some rivers, including the large Colorado River, no longer reach the sea at all, except in years of unusually high precipitation. Keeping enough water in rive…

Threats to Aquatic Environments - Freshwater Diversion And Use

Freshwater is a vital resource to humans. It is used for a variety of purposes—drinking water, hydroelectric power production, irrigation of crops, watering of livestock, and for commercial and industrial applications. Diversion of water from natural waterways, such as rivers and streams, stresses aquatic animals living in those habitats. The Klamath Basin in southern Oregon and northern Ca…

Threats to Aquatic Environments - Water Pollution Poses A Threat

Water pollution poses a considerable threat to many aquatic species. Contaminants include chemicals, biological substances (such as manure and sewage), solid waste materials, and dirt and soil eroded from riverbanks or nearby lands. In general, aquatic creatures are not killed outright by water contamination. A major exception is an oil spill, which can kill many creatures through direct contact. …

Threats to Aquatic Environments - Sediment—good And Bad

Erosion of river and stream banks brings dirt into waterbodies. Once in the water, this dirt is known as silt or sediment. Most of these particles settle to the bottom. However, sediment is easily stirred up by the movement of fish and other aquatic creatures, many of which spawn or lay eggs at the bed of their habitats. The dirt that remains in suspension in the water is said to make water turbid…

Threats to Aquatic Environments - Air Pollution Affects Water Quality

Water quality can be affected by pollutants emitted into the air during fossil fuel combustion or industrial, agricultural and forestry activities. Nutrients, oil and dirt particles, and some chemicals (such as mercury) are known to be carried through the air and deposited onto waterbodies. This process is called atmospheric disposition. In addition, aquatic environments can be harmed indirectly, …

Threats to Aquatic Environments - Fishing—far-reaching Consequences

Worldwide, the demand for fish and other edible aquatic creatures has risen dramatically in recent decades. The National Marine Fisheries Service in Fisheries of the United States-2004 (November 2005, http://www.st.nmfs.gov/st1/fus/fus04/index.html) summarizes data collected about commercial and recreational fisheries. The report notes that in 2003 the world's commercial fishery and aquacul…

Threats to Aquatic Environments - Unwelcome Guests—aquatic Invasive Species

Invasive species can be domestic or foreign. Some aquatic invasive species have been introduced purposely to U.S. waterbodies, for example, to improve sport and recreational fishing. Others have been introduced unintentionally. The primary source of these aquatic invasive species has traditionally been ship ballast water, which is generally picked up in one location and released in another. Accord…

Threats to Aquatic Environments - Multiple Threats Combine

Most aquatic lifeforms are not imperiled by a single threat to their survival, but by multiple threats that combine to produce daunting challenges to recovery. The lethal combination of historical overfishing and habitat degradation is blamed for the problems of many endangered and threatened aquatic species. Habitat degradation can be caused by many factors, including dams, water pollution, and i…

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