The Once and Future Reefs 1. Dinoflagellate residents of the reefs will die when stressed, leaving the coral polyps without their helpful symbionts. Human activities are destroying the reefs with pollution and physical damage. Life Along the Coasts A. Estuaries 1. Estuaries are partially enclosed regions where fresh and salt water meet.
Estuaries are incredibly productive feeding and breeding grounds for many animals.
B. The Intertidal Zone 1. The mid-littoral is submerged during the regular tide and exposed at the lowest tide of the day. The lower littoral is exposed only during the lowest lunar tide. C. Upwelling Along Coasts 1. Upwelling is the upward movement of deep, nutrient-rich water along the margins of continents.