What lives in the sand in the ocean?

Various organisms inhabit the sand in the ocean, including sand dollars, sea cucumbers, and various types of crustaceans like crabs and shrimp. Many burrowing species, such as clams and polychaete worms, also make their homes in the sandy substrate. These creatures often play essential roles in the ecosystem, contributing to nutrient cycling and serving as food for larger marine animals. Additionally, microorganisms like bacteria and protists thrive in the sand, further enriching the marine ecosystem.