South Sinai offers travelers quite a few unique natural gems. One of them is, undoubtedly, the Ras Mohammed Marine National Park, which has no equal in the Northern Hemisphere in terms of the quantity and quality of corals, marine flora and fauna. The Ras Mohammed Marine National Park ranks third in the world for the beauty of the underwater world, yielding the first two steps of fame only to the Australian Great Barrier Reef and the famous Maldives.
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The Ras Mohammed Marine National Park is located just 25 km from the popular Egyptian resort of Sharm El Sheikh on the southernmost point of the Sinai Peninsula, where the Arabian and Suez Gulfs meet. Ras Mohammed, opened in 1989, covers an area of 480 sq. km, two thirds of this space is the sea. Most of the visitors to Ras Mohammed come here to enjoy the vivid pictures of the underwater world. However, we came to Ras Mohammed National Park to see, first of all, very unusual plants - mangroves.
Mangrove plants are found on the border of land and sea along the tropical coast of the entire globe - the coasts of East Africa and South Asia, Australia and Oceania. One of the places where they grow is Egypt, where mangroves can be seen on the territory of the Ras Mohammed and Nabq national parks.
The first mention of the mangroves was left to us by Nearchus, one of the generals of Alexander the Great, back in 325 BC. During his voyage from India to Mesopotamia Nearchus discovered in the Persian Gulf thickets of unknown plants, which he called "forests growing from the sea." It is believed that the name of these plants - "mangrove" (mangrove) comes from the merger of two words: Portuguese mangue - which means "curve", and English grove - "grove". Dozens of species of mangroves and shrubs existing on our planet are united by a unique ability to grow on saline soil, very poor in mineral elements, periodically covered by tides. The homeland of mangroves is Southeast Asia. The southern coast of the island of New Guinea is distinguished by the greatest variety of mangrove plants in our time.
Mangrove plants are a group of various evergreen trees and shrubs that have developed a set of physiological adaptations that allow them to survive on muddy, periodically flooded areas of sea coasts and river mouths, in conditions of low oxygen content and rather high salinity of water. Mangrove plants are characterized by the presence of such morphological features as salt glands, succulence of leaves and ultrafiltered roots. Adaptations developed in mangroves for habitation in the intertidal zone are practically absent or extremely rare in communities of other plant types.
Mangrove plants are represented by 54 species from 20 genera included in 16 families. The most common types are red, black and white mangroves. Mangroves are under water on average up to 40% of the total time. Sea tides often flood plants to the top. Mangrove nutrients are obtained from salt water, while purifying it of organic impurities and other harmful substances.
In red mangroves, the roots of the plant desalinate more than 90% of the water using a kind of ultrafiltration mechanism. After passing through such a root "filter", the water contains only about 0.03% salt. All salt entering the plants accumulates in old leaves, which the plants then discard, as well as in special cell vesicles, where it no longer causes any harm to the plant. White (sometimes also called gray) mangroves can excrete salt due to the presence of two salt glands at the base of each leaf. The leaves of these plants are generously covered with white crystals of salt.True, we did not manage to see such crystals on the leaves, because three days before our arrival, a very rare guest of the desert - rain - hosted in these places.
To limit the loss of life-giving moisture through mangrove leaves, special mechanisms have also been developed. For example, they can restrict the opening of stomata on the surface of leaves, through which the exchange of carbon dioxide and water vapor occurs during photosynthesis; in addition, during the day, to reduce moisture evaporation, mangroves rotate their leaves in such a way as to avoid hot sunlight as much as possible.
Since mangroves live in areas where the soil is poor in nutrients, these plants have changed their roots to get the best possible nutrients. Many mangroves have developed a system of aerial or stilted roots that anchors the plant in semi-liquid silt and allows it to receive gaseous substances directly from the atmosphere and various other nutrients from the soil. The roots also accumulate gaseous substances so that they can then be recycled when the roots of the plant are under water at high tide.
Nature has taken very original care of protecting the reproduction of the genus of mangrove plants. All mangroves have floating seeds adapted to spread through water. Many mangrove plants are viviparous, not yet separated from the tree, their seeds begin to germinate. As long as the fruit hangs on the branch, a long sprout sprouts from the seed, either inside the fruit or through the fruit to the outside. The seedling formed in this way can feed on its own using photosynthesis, and when it ripens, it rushes down into the water. Water is the main means of transportation. For full maturation, the seedling must hold out in the sea for at least a month. During their sometimes very long swimming, the seedlings are able to endure drying out and remain dormant for even more than a year - until they get into a favorable environment.
When such a seedling - a traveler is ready to take root, it begins to control its position in the water, changing its density in such a way as to "roll over" and take a vertical position in the water - bud up, roots down. In this form, it is easier for him to stick into the mud and start life in a new place. If the seedling cannot take root in this place, it is able to change its density again and again set off on a new journey in search of more favorable conditions. But quite often the seedling grows so long that it reaches the mud before the fruit falls.
Mangroves are a very complex separate ecosystem. Mangroves contain coastal salinization and resist coastal erosion. Their fallen leaves serve as food for all kinds of microorganisms at the beginning of the food chain. Aerial roots, flooded with water, become a refuge for many small fish, shrimp, crabs and various marine microorganisms. Many species of migratory birds find a place for nesting and resting in mangroves, which are difficult to reach for humans and large animals. Parrots and monkeys live in the crowns of mangroves. Terrestrial animals feed on the leaves of some mangrove plants.
Once upon a time, mangrove plants occupied almost two-thirds of all coasts in the tropical latitudes of our planet. Today, the area of mangroves is shrinking at an alarmingly increasing rate, humanity has already lost more than half of the world's mangrove forests.
