Why is it important?
Water transparency is a key factor in ocean ecology as the sun is source of energy for all biological phenomena.
Transparency reduction is due to the presence of particles in the water. When light attenuates, it alters or limits the capacity of life of some of the biological communities that live in the sea. It reduces the possibility of photosynthesis (a process that produces the oxygen vital to the ecosystem). It implies as well a reduction of visibility which prevents fishes and zooplankton to see their prey and their predators. It has also some considerable effects on human perception of recreational water bodies, fishing or even health. When there is a harmful alga bloom for example, mussels cannot be collected because it would be dangerous for the health. This has important economic consequences.
Water transparency is therefore often used as an indicator of water quality.