The Groins are hard structures and used to maintain uplift beaches as to restrict longshore sediment transportation form tasking place. Are meant to capture sand transportation by the currents.
While the jetty is another type of shore perpendicular structure that is placed adjacent to the tidal inlets and controls the inlet migration. Both of them are used to destabilize coastal systems and disrupt the natural sediment regimes.
The Tropic of Capricorn (or the Southern Tropic) is the circle of latitude that contains the subsolar point on the December (or southern) solstice. It is thus the southernmost latitude where the Sun can be directly overhead. Its northern equivalent is the Tropic of Cancer.
