Geology (from the Ancient Greek γῆ, gē, i.e. "earth" and -λoγία, -logia, i.e. "study of, discourse") is an earth science concerned with the solid Earth, the rocks of which it is composed, and the processes by which they change over time. Geology can also refer to the study of the solid features of any terrestrial planet or natural satellite, (such as Mars or the Moon).
Andrew Herbert Knoll. Gaidos E, Knoll AH. Frontiers of Astrobiology. Cambridge: Cambridge University Press; 2012. Our evolving planet: From dark ages to evolutionary renaissance. pp. 132–153.
Josiah Gilbert Holland, in Rev. S. Pollock Linn Golden Gleams of Thought from the Words of Leading Orators, Divines, Philosophers, Statesmen and Poets, A.C. McClurg & Company, 1881, p. 280.
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.