The Kamchatka Peninsula, the Kuril Islands and the Japanese island of Hokkaido block the Sea of Okhotsk from the Pacific Ocean. Today a lot of work has been done to recognize the latter as internal for the Russian Federation, and there is every reason for this.
The Sea of Okhotsk occupies 1603 thousand km² of area, and its average depth is more than 1700 m. The sea has a significant maximum depth of more than 3900 m, but its western part is located above a gentle continental ledge, so the depths are quite small here. But today is our story about the shelf.
Definition of the term “shelf”
Since we are talking about the shelf of the Sea of Okhotsk, it is first of all necessary to give an exact definition of what the shelf is. This is a leveled part of the underwater margins of the continents, which adjoins land. The shelf always has common geological characteristics with the mainland. From English this word is translated as "sandbank".
In order to clearly determine which shelf is offshore, certain standards have been adopted. Shelves have borders that are called brow. In fact, this is a sharp inflection of the bottom surface, behind which the continental slope begins. But it was more difficult to enter the depths above the brow into the general standards. Basically, the depth is from 100 to 200 m. But in some seas, shelf depths are from 500 to 1500 m. For example, in the Sea of Okhotsk (in some places) the shelf is more than 1600 m deep.
Geomorphology of the shelf bottom of the Sea of Okhotsk
Geomorphology studies the reliefs of the earth's crust. The shelf of the Sea of Okhotsk is clearly divided into coastal shallows and the outer shelf. Shallow depths are characteristic of the coastal shallows - not more than 200 m. These are parts of the leveled surface of abrasion-accumulative origin.
The relief of the outer shelf is characterized by a complex structure. In this part, there are both large elevations and deep depressions. The most notable are the elevations of the Academy of Sciences and the elevations of the Institute of Oceanology. The deepest troughs that cut through this shelf are the trough of Deryugin and TINRO. Both the elevations and depressions of the outer shelf are former elements of the continental relief. The bottom surfaces of these areas, as well as offshore shallows, are aligned with abrasion. In the depressions of the bottom, marine sediments accumulate. The entire shelf has a continental type of the earth's crust.
Benthal Shelf Inhabitants
All reservoirs are divided into two biotopes. The water column is called pelagial, and the bottom is called benthal. Accordingly, the inhabitants of the bottom are called benthos. The shelf of the Sea of Okhotsk is populated by diverse benthos. Scientists have discovered in this place several hundred species of plants and thousands of species of animals. Here there are different types of snails, amphipods, wood lice, gammarids, isopod crustaceans, sea acorns, large colonies of mussels and bivalves live, there are hermit crabs, polychaete worms, oysters, fan crabs. Commercial gastropods and crabs are found in large numbers. The plant world of the shelf bottom is represented mostly by thickets of Fucus, scarlet, sea salad, zoster grass and other species.
Shelf minerals
According to forecasts, the hydrocarbon resources of the Sea of Okhotsk shelf are estimated at more than 6 billion tons of oil equivalent. To date, over 4 billion tons of oil reserves have been explored. The most significant deposits are contained in the Russian shelf off the coasts of Sakhalin, Kamchatka, the Khabarovsk Territory and the Magadan Region. The most studied deposits of the shelf of Sakhalin Island. 7 large oil and gas condensate fields and 1 gas field were discovered here.
Legal regime
For a long time, part of the water was considered an open sea. This meant that it was not included in the economic zone of Russia, although it was surrounded on all sides by it. Sea slang calls such territories “bagels”. The Okhotsk bagel occupied 52 thousand km². Many countries fished in this territory.
This conflict has arisen as a result of the fact that the law of the sea establishes the boundaries of the continental shelf within 200 nautical miles. Further, the international seabed extends. In 2001, Russian diplomats and scientists submitted an application to the UN commission for recognition of the disputed zone as Russia's continental shelf . The basis for the claim was that the bottom under the disputed area is a natural continuation of the mainland plate, which means it is the shelf of the Russian Federation. The first application was rejected. The second (more evidence-based) was filed in 2013. In 2014, a positive decision was made. Thus, it is officially recognized that the disputed middle part of the Sea of Okhotsk is the shelf. This means that it belongs to Russia.
The work done is very beneficial for Russia. The shelf of the Sea of Okhotsk is extremely rich in fossils and biological resources. The current precedent allows us to hope that other applications affecting the Arctic shelf will also be satisfied. However, studies on the Arctic shelf are carried out by many interested countries, so achieving positive results will be much more difficult.