Environmental Protection Agency, U.S

The first Earth Day, on April 22, 1970, highlighted a new commitment to environmental protection. Significantly, this year also saw the establishment of the U.S.

Erosion and Sedimentation

Erosion in the context of soil and watershed conservation is the detachment and movement of soil particles by natural forces, primarily water and wind. More broadly, erosion is the process of wearing away rocks, geologic, and soil material via water, wind, or ice (e.g., glaciers).


Estuaries are defined as semi-enclosed coastal bodies of water that have a free connection with the sea and within which sea water is measurably diluted by Taskinas Creek, a low-gradient, meandering tidal stream, snakes its way through York River State Park within the Chesapeake Bay National Estuarine Reserve in Virginia. A small subestuary of the York River is located on the river's southern side.

Ethics and Professionalism

The term "moral behavior" is applied in evaluating the personal conduct of a citizen and is judged in comparison to society's norms. The term "ethical behavior" is applied to that citizen's conduct in professional matters and is judged in comparison to the standards of the profession, which are formally expressed in statements called codes of ethics.


Sometimes called the "River of Grass," the Florida Everglades is one of the most extensive, complex, and renowned wetland ecosystems in the world. Located in South Florida, the Everglades is really a long, shallow river nearly 80.5 kilometers (50 miles) wide and more than 161 kilometers (100 miles) long.


At least 20,000 species of fishes live in the world's lakes, streams, estuaries, and oceans. Adult fish may be very small, such as the guppies that many people keep in their home aquariums, or extremely large, such as whale sharks that can weigh over 15 metric tons and reach 12 meters (about 40 feet).

Fish and Wildlife Issues

Fish and wildlife depend on water just as humans do. However, humans often reduce the access of fish and wildlife to sufficient quantities of usable water.

Fish and Wildlife Service, U.S

The U.S. Fish and Wildlife Service is a government bureau housed in the Department of the Interior.

Fisheries, Fresh-Water

In broad usage, the term "fisheries" refers to the capture and processing of sea, coastal, and inland aquatic animals and plants for commercial, recreational (sport), or subsistence (survival) purposes. The term "fishery" could refer to a small fresh-water stream, one of the Great Lakes, or the entire Atlantic Ocean.

Fisheries, Marine

People enjoy eating seafood, and eat a lot of it. The more than 6 billion people on Earth consume an average of 15.4 kilograms (almost 34 pounds) of seafood (marine and fresh-water plants and animals) each year.

Fisheries, Marine: Management and Policy

Marine capture fisheries are the source of livelihood for an estimated 200 million people worldwide. Yet they are imperiled by overfishing, habitat loss, and growing human demands.

Fishes, Cartilaginous

Sharks, rays, and chimaeras or ratfishes make up the cartilaginous fishes (Chondrichthyes), one of the two major groups of fishes. The other major group is the ray-finned fishes (Actinopterygii).

Floodplain Management

A floodplain is a land area subject to overflow from a river or lake, and to a variety of human management schemes. The management strategies encompass a spectrum from leaving the area in its natural state to comprehensive changes in both the water flow and the societal uses of the land.

Florida, Water Management in

In a sense, there are two Floridas: the north with hills, forests, lakes, and rivers; and peninsula Florida with flat expanses and large wetlands. Underlying the state is a system of aquifers.

Food from the Sea

Although a large percentage of the aquatic plants and animals that eventually become human food are either captured by fishers or produced by mariculturists in the world's oceans, a significant amount also comes from fresh water. The term "seafood" commonly is used to describe aquatic plants and animals consumed by humans, regardless of source.

Food Security

Influenced by prominent English economist Thomas Malthus (1766–1834), people in the nineteenth century began to fear that the planet Earth might not produce enough food for its growing population. Yet it turns out that Malthus was wrong.

Forest Hydrology

Forest hydrology combines aspects of two separate disciplines: hydrology and forestry. Hydrology is the science that studies the waters of Earth.

Fresh Water, Natural Composition of

Although water has the simple formula H2O, it is a complex chemical solution. "Pure" water essentially is nonexistent in the natural environment.

Fresh Water, Natural Contaminants in

Contaminated groundwater and surface water generally is associated with human-related activities such as illegal dumping of chemicals, over-application of agricultural chemicals, and improperly constructed or maintained septic systems. Yet natural chemicals, elements, or particles from the land and in the subsurface can affect the quality of fresh water, including its potability (drinkability).

Fresh Water, Physics and Chemistry of

Every water molecule (H2O) consists of one atom of oxygen and two atoms of hydrogen, as shown below. Each hydrogen atom is attached to the oxygen atom by a covalent bond in which the hydrogen atom shares an electron with the oxygen atom.

Garrels, Robert

Robert Minard Garrels revolutionized the use of experimental physical chemistry data for addressing problems in geology and geochemistry. His work helped bring about a new understanding of, and appreciation for, the use of physical chemistry methods and data in the earth sciences.

Geological Survey, U.S

The U.S. Geological Survey (USGS) is the nation's largest earth and biological science and civilian mapping agency, and has the principal responsibility within the federal government for appraising the nation's water resources.