What is the function of secchi disc ?

A Secchi disc is a simple, flat, white disk used to measure water clarity in bodies of water such as lakes, rivers, and oceans. It is lowered into the water until it is no longer visible, and the depth at which it disappears is recorded as the Secchi depth. This measurement is used to estimate the transparency of the water, which can provide information about the amount of suspended particles, algae, and other substances in the water. Monitoring water clarity with a Secchi disc can help scientists and researchers assess water quality, track changes over time, and understand the health of aquatic ecosystems.