What is the soil like in the kelp forest?

Question

What is the soil like in the kelp forest?

Answer 1

The "soil" is the bottom of the ocean - mostly sand mixed with the remains of  shells, coral, and wastes produced by the animals swimming above.  But this is what occurs between larger rocks which is what the kelp attach themselves to by way of holdfasts (like roots in that they anchor, but different in that they don't absorb water or nutrients).