How do lamp shells filter food particles from seawater?

Lamp shells, which belong to the phylum Brachiopoda, are lophophorates that utilize a specialized organ called a lophophore to obtain nutrients.12

To feed, the animal opens its shell and uses the lophophore—a horseshoe-shaped organ equipped with filaments—to generate water currents. This process is driven by the lashing of cilia, which are hairlike structures attached to the lophophore's filaments. These currents bring food particles, such as minute organisms or organic matter, toward the animal. Often, these particles are trapped in mucus and transported along grooves in the lophophore directly to the mouth.1

Some species further refine this process by using specific anatomical features to separate incoming, food-bearing currents from outgoing, waste-bearing currents. While the term "branchiopod" (a group of crustaceans) is sometimes confused with "brachiopod" (lamp shells), their feeding mechanisms differ significantly; branchiopods typically use specialized limbs to gather food, whereas lamp shells rely on their ciliated lophophore.13