Water clarity is more specific than water quality. The term “water clarity” more strictly describes the amount of light that passes through water or an object’s visibility in water. The term “water quality” more broadly refers to many characteristics of water, including temperature, dissolved oxygen, the amount of nutrients, or the presence of algal blooms. How clear the water appears is only one component of water quality.  
An underwater ecosystem can have high water clarity yet low water quality, and vice versa. Scientists have observed that many lakes are becoming less clear while also recovering from acid rain. This phenomenon has been seen in the northeastern United States and northern Europe. In the past, some lakes were ecologically bare, yet clear, while acidity was high. In recent years, as acidity is reduced and watersheds become more forested, many lakes are less clear but also ecologically healthier with higher concentrations of dissolved organic carbon and more natural water chemistry.