Question

What is the role of the anomalous behaviour of water in preserving aquatic life in regions of cold climate?

Explain the role of anomalous behaviour of water in preserving aquatic life in cold climate.

Answer 1

During the winter in frigid places, the temperature of the atmosphere drops significantly below 0°C. As the temperature drops, the water on the surfaces of lakes and ponds contracts. As a result, its density rises, and it sinks to the bottom. This process continues until the temperature of all the water in a lake drops to 4°C. As the water near the surface cools more, reaching temperatures below 4°C, it begins to expand rather than compress. As a result, its density drops, and it remains on the surface. The temperature of the water at the surface continues to decrease to 0 degrees Celsius. Finally, the water at the surface turns into ice, but the water behind the layer of ice remains at 4°C. Ice does not transfer heat well. As a result, the ice layer at the surface prevents heat from leaving the water and entering the atmosphere. Fish, other aquatic animals, and plants can survive in the water beneath the ice layer since the temperature remains at 4°C.

Answer 2

1. In cold climate, temperature of water in ponds and lakes starts falling.
2. On getting colder, water contracts. As a result, density of water increases and it goes down. To replace it, warmer water from below rises. This process continues till temperature of water at the bottom of pond becomes 4°C.
3. Water, due to its anomalous behavior, possesses maximum density at 4°C.
4. If the temperature lowers further, ice will form at the surface of a pond, with water below it.
5. Ice, a poor conductor of heat, blocks further heat exchange between the atmosphere and the water in the pond.
6. This prevents water freezing below the surface of ponds or lakes, enabling the survival of aquatic life.