The vibrant blue colors visible in this image are caused by phytoplankton bloom off Australia. The coastline is located in the Southwestern portion of Australia, several hundred kilometers East of Perth. The body of water seen here is a part of the Great Australia Bight, a large, open bay in the Southern Ocean.
Therefore the shoreline is comprised mostly of high reefs. The brown and tan colors visible in the image indicate the presence of desert; very little rainfall occurs there. As a consequence, very little runoff occurs and therefore the ocean receives very little in the way of nutrients, making the surrounding waters a virtual biological desert.
However, on occasion, currents deep beneath the ocean surface reach the coastline and are forced to the surface. Tiny, microscopic plants called phytoplankton are poised to rapidly exploit this temporary resource. Therefore growing very rapidly under such conditions. The area is also known for its sharks and Southern right whales.