The Color of Water

Di Vittorio sheds light on the science behind water’s many colors

​Water’s infinite hues, from captivating crystal-clear blues to sometimes off-putting murky browns, are influenced by a complex interplay of physics, biology, and chemistry. Faculty Affiliate Dr. Courtney Di Vittorio, an engineer who studies water resources, explains the dynamics behind water’s appearances in a recent piece for The Conversation’s “Curious Kids” series. Pure water naturally exhibits a slight blue tint due to its absorption and scattering properties. Crater Lake’s famously blue hues owe to the lack of streams carrying sediments into its depths. On the other hand, the presence (or stirring up) of things like silt, algae, or organic matter can alter this intrinsic color, leading to greenish or brownish appearances. For example, Florida’s Lake Okeechobee absorbs significant runoff from highly developed areas, including farm and lawn fertilizers, leading to excessive and harmful algae levels. Scientists use these variations to guide assessments around pollution levels and safety for activities like swimming or fishing. ​