What does the underwater world look like?

The seabed is part of the solid surface of the Earth, so it is not as flat as we think, and it has ups and downs. If the sea really turns into mulberry fields, we will find that the appearance of the underwater world is very similar to the land we live in, with majestic mountains, deep trenches and canyons, and vast plains. The seabed of the world's oceans resembles a large basin of water, with a shallow continental shelf at the edge, a deep-sea basin in the middle, and a deep sea basin on the ocean floor.

According to a large number of bathymetric data, we know that the basic outline of the seabed is such a coastal land, extending outward from the coast, which is a relatively flat seabed with a small slope, this area is called the "continental shelf"; Further out there is a rather steep slope, descending sharply to a depth of 3,000 meters, and this slope is called the "continental slope" from which you descend to the vast bottom of the ocean. The continental shelf and continental slope account for about 20% of the total ocean area, and the ocean floor accounts for about 80%. The seabed topography of the shallow seabed of the continental shelf is generally not very undulating and is covered with a layer of sediment and gravel of varying thickness, which is mainly carried from land by rivers.

However, in some places (such as the Pacific coast of North and South America and the Mediterranean coast), the mountains are close to the sea, and the seabed terrain is relatively rugged and steep; In some places (such as the coast of the Yellow Sea and the estuaries and bays of the lower reaches of the great rivers) the land is flat, and the seabed is also a wide continental shelf with little undulation. The bottom of the ocean is located at a depth of several thousand meters. The ocean floor is mainly deep-water basins, deep-sea large plains, large-scale submarine seamounts and submarine plateaus, as well as some isolated ocean-bottom volcanoes, huge coral islands and reefs, etc.

These terrains, unlike terrestrial terrain, are formed in the ocean. The bottom surface of the ocean is covered with a layer of seafloor sediment of modest thickness, called abyssal soft mud. The majestic submarine mountains, the vast submarine plains, and the deep ocean trenches are all covered with varying thickness.

1. The fiery red or black sediments decorate the ocean with majestic and majestic magnificence. The seafloor profile is determined by the crustal structure of the seafloor. The oceanic crust is dominated by basalt layers with a thickness of about 5 km, while the continental crust is dominated by granite layers with an average thickness of 33 km.

The ocean floor is always renewed and growing, and about 6 centimeters of new ocean floor is reborn every year. The mid-ocean ridge is the "backbone" of the ocean floor uplift, and the total length of the world's mid-ocean ridge is about 80,000 kilometers, accounting for 1 3 of the ocean floor area, and the seafloor expansion begins here.

Beneath the huge thick layers of water in the ocean, there are tens of thousands of kilometers of mountain ranges, thousands of square kilometers of large plains, basins and volcanoes that have erupted or are in the process of erupting, and of course, you can also find two steep slopes and extremely magnificent underwater canyons. After more than 100 years of surveying and research, it has been found that most of the submarine canyons are distributed on the outer edge of the continental shelf at the edge of the ocean, and the canyons are winding and curved, with branch valley channels, and the valley floor slopes downward, often extending from the shallow sea shelf or the upper part of the slope to the bottom of the slope with a water depth of more than 2,000 meters.

In the world's oceans, the length of submarine canyons, the height of the valley walls, and the slope of the valley floor vary greatly. The short submarine canyon is only six or seven kilometers long; The long submarine canyon reaches hundreds of kilometers. The walls of submarine canyons are generally 800 900 meters high.

Currently, the deepest canyon ever discovered, the Grand Canyon of the Bahamas, has a height of 4,280 meters on its walls. In fact, it is difficult to accurately measure the wall height of an undersea canyon, and the above data is calculated based on data obtained from bathymetry technology.

1. At that time, the moon passed through the meridian. Jupiter rises in the east. In the midst of this peaceful nature, the sky and the sea compete with each other to be quiet, and the sea makes the moon ring of the night the most beautiful and sleepy mirror, and I am afraid that this mirror has never been so beautiful to reflect the shadow of the moon.

2. The wind blew to the east, and the moon was revealed. The sea sparkles under the moon. This merciful moon has rekindled our resentful strength.

3. The scene of the seabed is also very different from the underwater forest in the previous time, there is no fine sand, seagrass, and no forest.

4. The sunlight casts on the quiet seabed, as if it is a ray of light that is tortuously analyzed through the spectrum, which is beautiful. Even the rocks, plants, shells, and corals at the bottom of the sea are dyed in the sun's colors, which is amazing.

5. The shape of the trees is very strange, and the branches and leaves are stretched towards the sea surface, and do not sway with the water waves. And even if you bend it hard, it won't be long before it returns to its original shape. The forest floor is undulating and interspersed with small rocks, making it difficult to walk.

The professor found that at the bottom of the sea, animals and plants were simply indistinguishable.