Underwater flashlights: What light can tell us about water quality

Water is essential for life. The particles and dissolved chemicals found in rivers, lakes, and oceans are constantly changing with weather, seasons, and human activities. The substances found in water can be helpful or harmful to humans and other organisms. New technologies allow scientists to use waterproof computers (called sensors) to record the quality of water as it changes throughout the day or night. Many sensors use the interaction of water with light, or other energy forms, to learn about what is in it. Through observing what happens to light energy in water, scientists can reveal the sources and movements of harmful pollutants or essential nutrients for plants, animals, and bacteria. Networks containing many sensors work together to provide continuous information about the ever-changing conditions that affect all living organisms that depend on water.