Marine erosion: types, examples and consequences

Let’s start by clarifying what marine erosion consists of, that is, what is the definition of marine erosion . We can say that it is about the continuous wear of the coast and also the elimination of sediments, caused mainly by the effect of waves and marine currents and, to a lesser extent, by the tide and marine fauna.

Some of the characteristics of marine erosion are the following:

• This phenomenon happens both in rocks and in sand.
• The speed of wear is determined by the amount of rocks present on the coast.
• The fewer the rocks, the faster the erosion process.
• With regard to the large rock formations, they are not homogeneous but rather have softer rocky areas.
• In areas of softer rocks, erosion can act more intensely, giving rise to different formations due to marine erosion, which we will discuss in another section.

As we mentioned in the previous section, marine erosion is mainly caused by the effects of waves and ocean currents. This is how sea erosion occurs :

Waves

Waves are a powerful force that causes marine erosion due to coastal degradation , and their strength can triple during storms. They are made up of two movements: the first, constructive movement, where the wave rises and hits the shore, degrading it. The second, backward movement, in which the wave retracts and carries sediment . Although the waves are continuously degrading the coasts, the modifications by erosion take thousands of years. Here below we show you a short video about the waves.

Ocean currents

The main effect of ocean currents is sediment carry-over. When the wave retracts, it produces a bottom current, that is, a movement in a perpendicular direction with respect to the current of the wave, in which it carries sediment from the coast. In addition, currents can occur in a parallel direction, when the waves hit the shores obliquely.

Next, we will tell you about the different types of marine erosion that exist and their particularities.

Abrasion

It happens due to friction between the rocks on the coast and those that are carried by the waves. The results of abrasion depend on the size of the rocks and the speed of their movement.

Hydraulic starters

Hydraulic starts occur when sediment is poorly settled. When the waves hit them, the sediments are completely washed away.

Corrosion

Here the salts present in the sea come into play (here we will tell you why sea water is salty ). They have the ability to dissolve many materials, including limestone rock. In this way, the rock breaks down into small pieces and contributes to abrasion.

Biological processes

Marine fauna intervenes in biological processes , however, their involvement in marine erosion is practically insignificant. Its effect is due to the fact that some marine animals, due to their behavior, are capable of degrading the rock or transporting fragments of limestone rock to form coral reefs. For its part, marine vegetation also influences erosion since its roots facilitate the breakdown of rocks.

Marine erosion is one of the processes of relief and geoform formation. For this reason, here we will show you which geoforms are caused by marine erosion :

• Cliffs: one of the best known marine geoforms is cliffs. They are defined as steep rocky slopes caused by the continuous crash of the waves.
• Marine arches: they are cliffs that have a perforation. Said drilling is the product of intensified coastal erosion processes in a particular area.
• Sea caves : sea caves originate when the wear of rocks of less hardness than the rest of the rock of the cliff occurs.
• Littoral arrows: they are produced by the deposit of sediments arranged parallel to the coast. Littoral arrows are usually attached to the shoreline at some point.
• Abrasion platforms: these are rocky platforms eroded by the action of the sea, which can be seen when the tide reaches low level

If you read this far, you will know that the marine erosion process is responsible for the various coastal reliefs that exist. However, the formation of the relief is not the only effect of marine erosion .

This erosive process has important economic consequences for coastal cities. To understand these consequences, we must bear in mind that the sea mist disperses beyond the coast and with it carries the same salts that cause the corrosion of rocks, a process described above. Like rocks, all material that is exposed to sea salts undergoes some type of degradation and, therefore, the construction materials of houses, buildings and more are not free from this degradative process.

After learning all this and seeing some images of marine erosion, you may now want to expand your knowledge by reading these other articles on What is water erosion, types, causes and consequences and Types of erosion .