Explain how the properties of water are important to organisms that live in rocky intertidal zones, where they are exposed to air and direct sunlight at low tide.

Water has a high specific heat capacity, so large amounts of heat energy are needed to raise its temperature. This means that when the tide goes out and organisms are exposed to direct sunlight, their body fluids and cells do not heat up rapidly, preventing overheating and large temperature fluctuations.

Water also has a high latent heat of evaporation. A large amount of energy is required to evaporate water, so the loss of water from the organisms’ bodies is slow. This reduces desiccation and helps prevent dehydration when the organisms are exposed to air and sun.

Finally, water is an excellent solvent and many metabolic reactions require water as a reactant or medium. By retaining water, the organisms can continue to carry out essential chemical reactions and maintain their metabolism even during low tide.

These properties of water therefore protect intertidal organisms from overheating, dehydration and metabolic disruption when they are exposed to air and direct sunlight.