Ebb tide in the context of "Rip tide"

Mangrove forests, also called mangrove swamps, mangrove thickets or mangals, are productive wetlands located in tropical and subtropical intertidal zones. Approximately 80 mangrove species exist, all adapted to areas where slow-moving water allows for the deposition of fine sediment and low-oxygen soil conditions. These trees cannot endure freezing temperatures, which restricts their distribution to warmer climates.

Their distinct, stilt-like roots allow the trees to slow the movement of tidal waters, causing the settlement of suspended sediments and acting as a protective barrier to reduce coastal erosion. These roots also provide an important habitat for many species.

Southern dispersal, also known as the great coastal migration or rapid coastal settlement, was an early human migration along the southern coastal route, from the Arabian Peninsula via Persia and India to Southeast Asia and Oceania, with later descendants of those migrations eventually colonizing the rest of Eastern Eurasia and the Americas.

According to this thesis, the dispersal was possible thanks to the development of a multipurpose subsistence strategy, based on the collection of organisms, fish, crustaceans, molluscs, algae, which are part of the biotic communities of the intertidal zone, the transition ecosystem between land and sea between the upper limit of high tides and the lower limit of low tides, i.e. organisms left behind by the waters which retreat during ebb tide, and which people could harvest from the ground and reefs left unsubmerged or in shallow water at low tide. - In support of this hypothesis there are the remains found on an ancient Pleistocene reef, now emerged, near the locality of Abdur in Eritrea. Its rocks are the result of the compaction of marine debris about 125,000 years ago and contain fossil remains of a complex biotic community of the coast of the time: large colonies of corals, oyster shells, large clams and other bivalve molluscs, gastropods and echinoderms. A group of geologists and paleontologists found many blades and tools made of quartz, obsidian and other fine volcanic stone, mixed with the remains of shells. This would prove that over 100,000 years ago human populations of Homo sapiens exploited the intertidal zone for food purposes.

In hydrology, a current in a water body is the flow of water in any one particular direction. The current varies spatially as well as temporally, dependent upon the flow rate, stream gradient, and channel geometry. In tidal zones, the current and streams may reverse on the flood tide before resuming on the ebb tide. On a global scale, wind and the rotation of the earth greatly influence the flow of ocean currents.

In a stream or river the current is influenced by gravity; the term upstream (or upriver) refers to the direction towards the source of the stream (or river), i.e. against the direction of flow. Likewise, the term downstream or downriver describes the direction towards the mouth of the stream or river, in which the current flows. The terms left bank and right bank refer to the banks as seen from the direction of flow, in the downstream direction.