Hobbies And Interests
Water Temperature and Dissolved Gases
As its temperature increases, water holds less essential dissolved gases, including oxygen. Fish and other aquatic life come under stress when water temperature rises, as there is less oxygen available to breathe; too little dissolved oxygen can drastically alter an aquatic ecosystem. If the fish in a river or lake are showing signs of stress, scientists can monitor water temperature with thermometers to determine if thermal pollution is a factor.
Sources of Thermal Pollution
Some types of industrial equipment and power plants require large-scale cooling to keep machinery running properly; in many cases, a nearby river or lake serves as a convenient source of cooling water; after use, the water returns to the river or lake, warming it. Laws typically limit the temperature of discharged water to prevent environmental damage, making temperature monitoring a necessity. Thermal pollution can also be a lowering of water temperature, as when cool water in a reservoir is discharged into a warmer river or lake.
Using a Thermometer
Scientists use special thermometers to monitor water temperature; they have precise temperature markings to a fraction of a degree and are extra rugged to stand up to demanding outdoor conditions. A scientist lowers the thermometer into the water by means of a string or rope tied to the thermometer̵7;s case, then raises it after a few minutes to record the temperature. Convenient digital electronic thermometers for monitoring water are also available.
Infrared Camera
In addition to thermometers, scientists also use infrared cameras to study water temperature. Although they are much more expensive than traditional thermometers, the cameras render the temperature as a range of colors, clearly identifying hot and cold spots in a body of water. When the pictures are taken from a plane or satellite, an infrared camera can capture entire streams, lakes and even oceans in a single image.