Sand movement and erosion
People can also have problems when they
build something on or close to beaches. The wind can move the sand and
cause the sand dunes to start wandering, and with time engulf buildings
and other man-made constructions. When such a situation is evident, plants
are planted to try and stabilize the sand dunes and stop sand movement.
Waves and currents also have the ability to erode and carry
away beach material, so that constructions that were earlier situated
far from the beach come closer and closer to the shoreline. When such
a situation arises, such constructions run the risk of being undermined
and destroyed. This type of erosion is difficult to stop.
Nice things can show up
Erosion together with land elevation (isostatic
re-adjustment) can also have positive efftects - if you are interested
in Marine organisms. Since the several kilometre thick ice caps from the
last ice age melted (about 10 000 years ago), most of the Swedish
coast, except for Skåne, is increasing in height above sea level.
Because of this, it is possible to find shells,
i.e. mussels, washed up onto the beach that were, many years ago,
living in water that was several metres deep. Without land elevation and
erosion we would seldom find the remains of certain deep bottom-living
organisms on the shore.
Sand bottoms as living environments
The bottom-living environment is affected
by several factors, amongst the most important are wave movement, particle
size and the amount and type of decaying organic material.