Water Transitions

Essay by Matt PinderA+, November 1996

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Brackish water is a fairly salty mixture of freshwater and sea water. It is

unique in numerous ways and is a life giving ecosystem. To understand what

brackish water is, a background should be known about its sources.

First of all, there is freshwater. Out of all the water on the planet, only three

percent of it is fresh, and only one fiftieth of one percent is readily available.

Freshwater is not pure in that it contains minerals and other particles. There are

numerous plants and animals that depend on freshwater for their lives. Humans are

one of them. Seventy percent of the human body is made up of freshwater (744


Next, there is saltwater, or seawater. Seawater consists of fifty-five percent

chlorine, and thirty-one percent sodium (Groliers). It makes up approximately

ninety-seven and two tenths percent of the total volume of the world's water, and

covers more than seventy percent of the earth's surface (Groliers).

Sea water

doesn't just contain hydrogen, oxygen, sodium, and chlorine; it also contains every

naturally occurring element. Although seawater has a fairly constant ratio of major

elements, salinity and seawater can fluctuate. Normally, the salinity is thirty-four to

thirty-seven parts per thousand (ppt.), but on a particularly rainy morning, the salinity

may decrease to something as low as thirty-two ppt. (Stuller 29).

The mixing of freshwater and sea water forms a third type of water, known as

brackish water. Brackish water can be found in a variety of mixing zones such as

river deltas, freshwater title marshes, estuaries, fjords, and in the middle of the


(Stuller 30). To begin with, freshwater traveling towards the sea carries suspended

particles. As the particles make contact with saltwater, an electrochemical reaction

called flocculation takes place. The clay with a positive charge, and the sodium...