Areas strongly influenced by large, unidirectional, organized, coherent flows of water in horizontal motion. These include freshwater inflows and tidal flows. Geostrophic flows are currents in the deep ocean that flow along lines of constant pressure or baroclinic surfaces. Wind-driven currents along the shore, called longshore currents, flow parallel to the land and play a role in sediment transport and structuring of the habitat. Current systems play an especially important role by governing productivity, providing transport for early-life stages (e.g. eggs and larvae) and adults, and flushing pollutants out to sea.