Underwater at a pier in the Yaquina Estuary in Oregon. Underwater piers and docks in particular act as artificial reefs, harboring an abundance of shallow-water fish. While not intentionally designed to attract marine life, these partially underwater structures often serve as oases for both common and extraordinary organisms in locations that may otherwise amount to aquatic deserts. Even though the diversity of life under piers may seem to be relatively sparse when compared with healthy Pacific coral reefs, the sheer variety of animals, plants and microorganisms drawn to these man-made formations can be vast and the associated food web exceedingly complex.