Ebbs

Ebb is the period in the tide cycle when the water level falls and the shoreline recedes toward the sea. The term is used as both a noun (the ebb) and a verb (to ebb). In nautical language, ebb tide denotes the outgoing phase of the tide, opposite the flood tide, which is the incoming phase. Ebb is part of the regular rise and fall of coastal waters.

Causes and dynamics: Tides are generated primarily by the gravitational forces of the Moon and the Sun. At a coastline, the tidal system consists of two daily bulges; as the bulge near the land passes, water rises to high tide, then flows away, creating the ebb current. The rate and timing of an ebb are influenced by coastline shape, ocean floor depth (bathymetry), coastal orientation, and local wind and atmospheric pressure. In some places the ebb can be rapid, channelized by estuaries or seafloor features.

Implications and uses: Ebb currents affect navigation, harbor operations, and fishing schedules. They influence the exposure of tidal flats, allowing certain organisms to feed at specific times. Tidal energy projects may exploit ebb phases for generation. In poetry and prose, ebb is often used metaphorically to describe decline or receding prospects.

Origin and terminology: The word ebb derives from Old English ebban, meaning to recede. Ebb and flow pair describes the alternating movement of water between high and low tides. The term is widely used in oceanography, coastal geography, and navigation.