These three symbols all involve oceanic preservation and awareness. The first is coral reef destruction (left). Australia is represented because it harbors a large amount of the coral reef. The negative space in the middle is an image of a piece of coral. The coral looks as if it is spreading through Australia, much like awareness for the coral reef should be spreading.
The next two (middle, right) are representations of oil in our ocean. The middle image deals with the separation of oil and water and how they should not go together and need to be separated, which makes a lot sense considering they literally don't mix. The image on the right is for offshore drilling and how it is turning our water black due to oil spills, leaks, and damage to the ecosystems of the ocean.