the sea is close

In the geological annals of our planet, algae also left an imprint in the form of stromatolites, diatomites and limestones.

Algae act as producers also in terrestrial habitats, in particular, most often in those that are not suitable for the life of higher plants.

Algae play an important role in the synthesis of organic matter on Earth. In the complex of organisms that carry out the cycle of substances in nature (producers — consumers — reductants), algae together with autotrophic bacteria and higher plants form a link of producers, due to which all chlorophyll-free organisms on the planet exist.

The speed of sound in water does not depend on its frequency and height and ranges from 1,450 m/s to 1,570 m/s, and with increasing temperature, salinity, and pressure (i.e., depth), this value increases, but most under the influence of temperature.

On average, with a temperature change of 1 °C, the speed of sound changes by 4.4 m/s, with an increase in salinity by 1 ‰ — by 1.2 m/s, with an increase in depth by 100 m — by 1.75 m/s.

The highest water level occurs in narrow bays of the open sea or ocean. For example, the height of tides in the Bay of Fundy on the east coast of North America reaches 18 m.

High tide occurs when the Moon passes through the meridian of a given place. The same thing happens simultaneously on the opposite side of the Earth. So, if the Moon passes through the zero meridian, then the tides are observed on the 0° and 180° meridians, and the ebb tides are 90° long in both hemispheres.

Marginal seas, located near the motherland on continental shoals and slopes, not far from land, are characterized by a wide connection with the ocean, and are sometimes separated from the ocean by a chain of islands.

Depending on the number of continents whose shores the sea washes, internal seas are divided into intercontinental (Mediterranean and Red Seas) and intracontinental (Yellow, White, Black Seas, etc.).