For a Curious Mind,
Sea foam is created in a healthy ocean environment, and is completely harmless to humans (for the most part). It is made from algae and other decaying organic material (ewww 🤮) being crashed into by waves. But why is there so much of it? Well essentially, they are just lots and lots of tiny bubbles being created with the force of the waves into the shore. And they end up sticking to the sand and staying there.
I hope this helped,
Dear Letterbox