This pattern has been called intertidal zonation. Although Intertidal Zonation as a concept is usually only applied to rocky shore animals and algae, it also occurs on sandy and muddy shores . In this web site I will use a generalised scheme based on assumed tide levels for any Australian shore. In southern Australia, on high-energy sandy beaches, the sand is coarse and generally slopes away into the water. This is a constantly shifting environment, with sand grains buoyed up in the water when the tide is high.
Animals have to be very specialised to live here.
These beaches have the lowest number of animals. Protected beaches have fine sand, which if supported by water, is easy to bury down into, and always remains moist. Here a very large range of microscopic animals move among the sand particles in suspension. In Australia we know very little about these minute animals. No large algae can survive here, only microscopic algae.