The document provides an overview of coastal environments and properties of water. It discusses that 97% of water on Earth is in oceans, with the remaining 3% being fresh water. Water covers around 3/4 of the Earth's surface. More than half of the world's population lives within 60km of a coastline. Water has unique properties like absorbing or releasing heat during temperature changes, being a good solvent, and existing in three physical states. Coastal systems include beaches, rocky coasts, estuaries, deltas, and reefs. The document then discusses various chemical and physical properties of water in more detail.