Continental Shelf

Author: Manan Agrawal


What is Continental Shelf?

Continental Shelf is the submerged part of the landmass of a continent into the sea. It’s an edge of the continent that lies underneath. Though under the sea, it forms part of the continent. Geologically, it is defined as an immersed extension of a coastal state. A continental shelf consists of seabed and subsoil. It extends from coastline to a drop off point called the shelf break.

If we talk about the boundaries of the continent, it does not start with the coastline shore but from the edge of the continental shelf itself.

Structure of the Continental Shelf:

The Continental shelf can be wide or narrow with a steep or gentle slope depending upon the formation of the coast. The shelf shallower than other formations of the coast and that is the reason light can reach there. Its gradient or Slope is 1° or even less. A part of the land of the continent may break and drop in elevation setting in as a portion of the shelf. Ocean water also deposits sediments and rocks on the bed of the shelf. Certain areas of a continental coast have no shelf. These usually occur where there is a meeting of tectonic plates at the coastline.  It does not include the deep ocean floor.

Accordingly, they are narrow, rough, and steep off mountainous coasts but broad and comparatively level offshore from plains. These are generally coated with a layer of sand, slits, and silty muds. Surface features small hills and ridges that alternate with shallow depressions and valley-like troughs. The standing height of the crust is determined by the density and thickness of the crust.

Why is Continental shelf important?

The shelves make up less than 10 percent of the total area of the oceans. Yet all of the ocean’s plants and many types of algae live in the sunny waters.

Water depth over the continental shelves averages about 60 meters (200 feet). Sunlight penetrates the shallow waters, and many kinds of organisms flourish—from microscopic shrimp to giant seaweed called kelp. Ocean currents and runoff from rivers bring nutrients to organisms that live on continental shelves. This is important for many animals, including most of our major fishery species, because bottom habitats are generally safer than open ocean habitats due to the complexity of the environment. Any habitat that combines food availability with safety is going to be prime real estate. Some results of this are that a huge proportion of the fish we eat either comes directly from continental shelves or spends at least part of their life cycle on continental shelves.

A lot of fuel we use is collected from beneath the continental shelves. They also play an important part in predicting earthquakes and other natural phenomena.

Perhaps, the most notable feature of Continental Shelves is their use in understanding Earth’s history.

Guidelines and appropriate Laws:

The Law of the Seas governs the Limits of the Continental Shelf. The law of the sea is a body of customs, treaties, and international agreements by which governments maintain order, productivity, and peaceful relations on the sea. NOAA’s nautical charts provide the baseline that marks the inner limit of the territorial sea and the outer limit of internal waters.

The shelf has been defined as extending either to the edge of the continental margin or to 200 nautical miles from the baseline, whichever is further. The Coastal States do not have to proclaim a continental shelf, but they must define its limits. Where the physical limits of the continental shelf extending beyond 200 nautical miles, the coastal State must delineate it, according to one of several formulas, using straight lines that do not exceed 60 nautical miles in length. A Commission on the Limits of the Continental Shelf makes recommendations to coastal States on matters related to the establishment of outer limits of the continental shelf where they extend beyond 200 nautical miles.

North Sea Continental Shelf (Federal Republic of Germany/Netherlands) case-

These cases concerned the delimitation of the continental shelf of the North Sea as between Denmark and the Federal Republic of Germany, and as between the Netherlands and the Federal Republic, and were submitted to the Court by Special Agreement. The Parties approached ICJ to state the principles and rules of international law applicable and undertook thereafter to carry out the delimitations on that basis. The Court, having found Denmark and the Netherlands to be in the same interest, joined the proceedings in the two cases. The Judgment which was delivered in 1969, the Court found that the boundary lines in question were to be drawn by agreement between the Parties and in accordance with equitable principles in such a way as to leave to each Party those areas of the continental shelf which constituted the natural prolongation of its land territory under the sea, and it indicated certain factors to be taken into consideration for that purpose. The Court rejected the contention that the delimitations in question had to be carried out in accordance with the principle of equidistance as defined in the 1958 Geneva Convention on the Continental Shelf. The Court took account of the fact that the Federal Republic had not ratified that Convention, and held that the equidistance principle was not inherent in the basic concept of continental shelf rights and that this principle was not a rule of customary international law.