Translation is the communication of the meaning of a source-language text by means of an equivalent target-language text. The English language draws a terminological distinction (not all languages do) between translating (a written text) and interpreting (oral or sign-language communication between users of different languages); under this distinction, translation can begin only after the appearance of writing within a language community.
In the marine environment human activities and other factors can result in algal blooms and habitat destruction, which may affect people's health and local communities. A common method for assessing the status of water quality is by measuring its optical properties to determine sewage impact, dissolved organic matter, sediment loads or biological activity.