Not every beach is made of sand.
In fact, there are beaches that are made up of volcanic rocks, pebbles, shells, and coral. I’ve been lucky enough to snorkel from a beach that was made up of dead, broken pieces of coral that were piled up from thousands of years of heavy coastal storms. What materials a beach is comprised of can tell you a lot about the area, including how much energy is involved through wind and wave action, what the waves are like, and the history of the beach—but those are topics for another post!
Today we head over to Australia, the continent of many species that could and will kill you. However, the beach that I’ll be talking about is probably one of the safest places to swim, especially for those who aren’t strong swimmers.
Shell Beach, is found within Western Australia’s Shark Bay, making it an embayed beach. This beach is unique for a few reasons.
The first unique feature is that the immediate water has a salinity that is twice that of the ocean! This occurs because the rate of evaporation is greater than the rate that rain falls, so more water is lost due to the heat than is replaced. When the salt water evaporates, the salt stays behind. Add to this the fact that a massive sea grass bed sits at the mouth of the bay, blocking a lot of tidal flow, and this makes for a super salty environment.
But it’s okay, because this leads into the second unique thing about this place. The salty water conditions have created a safe haven for a specific kind of shelled creature, Fragum erugatum, which is a species of cockle. A cockle is a bivalve—its shell is divided into two halves—and it is very similar to oysters and clams.
The f. erugatum cockle can survive the hypersalinity of the waters of Shell Beach, but its natural predators cannot, meaning that this species thrives in this place. In fact, they’ve survived here in L’Haridon Bight for thousands of years with no decline in their population.
How can we tell? When shelled organisms die, their bodies are consumed or they decay, leaving only their shells behind. So when f. erugatum cockles die, their shells remain in the area, and over thousands of years their shells eventually replaced all the sand and other sediments of the beach.
Today, Shell Beach stretches for about 44 miles and is comprised of only cockle shells, and the shells extend about 26−30ft down below the immediate surface. That’s a lot of shells! The shells even make up the sea bed and stretch quite a ways into the bay. On the back part of the beach there are so many shells that they’ve fused together in places to form large hard shapes, which were mined for a while to make decorative blocks until Shark Bay became a protected site.
I think this beach would be a cool place to go because it is so different. Not a lot of creatures can survive the water, so you don’t have to worry so much about potential animal accidents. And the water is easy to float in, much like the Dead Sea in Jordan, so it’s a great place to relax and float in peace. Also, the beach is a pretty snow-white color and was created in such an inspiring way, at least to someone like me!
Sources and cool links:
Ocean: The Definitive Visual Guide made by the American Museum of Natural History