Some people say that what's fun about the coast is that all you see is the sea. Apart from the beach, there are also reefs at the foot, which is too monotonous compared to high mountains, canyons, forests, and grasslands.

People who say this may not have enough understanding of China's coastline. China is a maritime power with a blue land area of 3 million square kilometers and a continental coastline of over 18000 kilometers. From the steep bedrock coast of reefs to the soft and soothing sandy coast, from the muddy coast that attracts countless seabirds to the vibrant and colorful mangrove and coral reef coasts, the landscape types and natural ecology are rich and colorful, and each coastal type is greatly observable, worth savoring slowly. Let's walk into this unique land and sea world together and see how exciting China's coastline is.

China's land boundaries and coastline, mapping @ Lepersil/visualizing planets

The continental coastline, as the name suggests, is the boundary between land and the ocean. The Terrestrial ecosystem and marine ecosystem are constantly crisscrossing here, creating rich resources. The coastline of our country includes both mainland coastline and island coastline, with a winding shape and a total length of about 1.5 times that of the land boundary.

The interaction between sea and land has formed a variety of coastal landforms, mainly divided into two categories: plain coast and mountainous and hilly coast. In the Tropic of Cancer and to the south, driven by the subtropical and tropical Seasonal tropical forest climate, mangrove coast and coral reef coast are formed here.

The natural distribution range of mangroves is between Sanya in Hainan Province and Fuding in Fujian Province; Coral reefs are distributed along the coast of the South China mainland, as well as on islands in Taiwan, Hainan, and the South China Sea. There are both typical coastal reefs and island type coral reefs.

Huidong Yanzhou Island Mangrove Wetland Protection Zone

What is' mangrove forest '? It is a cluster of trees growing on the mudflat of the coastal Intertidal zone. When the tide rises, some of these trees are completely submerged, and some only part of the crown is exposed on the water surface. When the tide ebbs, the trees and the silt under their feet will be completely exposed. In this unique forest that is often soaked in seawater, whether it is fish, shrimp, snails, crabs born under trees, water birds living on trees, or even the trees themselves, they have developed a special set of survival skills to cope with rising and falling tides.

Coral reefs in Wenchang, Hainan

And coral, besides coastal residents, most people have heard of it because it has been a rare treasure since ancient times. Coral is a spirit from the sea, a gem that embodies life. That life is a coral worm. Coral insects enjoy social life the most, reproduce quickly, the old constantly die, the new constantly grow, and so on. The bones built up accumulate sand and become towers, eventually forming coral reefs, a colorful underwater garden. And these two huge ecosystems have created the two most important biological coasts in China.

The sediment carried by rivers accumulates in the estuaries and coastal zones on both sides, coupled with the complex and varied coastal geological structures, forming a long and diverse coastal wetland here. For example, coastal marshes, estuarine deltas, mudflat, mangroves, etc.

Main Coastal Landform Types, Mapping @ Lepersil/Visualized Planet

Distribution of Major Coastal Wetlands, Mapping @ Lepersil/Visualization Planet

Coastal wetlands contain abundant resources. Regular tides bring small fish and Invertebrate in the sea to the shoal. These small creatures are a feast in the eyes of waders. Therefore, mudflat wetlands attract a large number of waterfowl to come here to feed and roost when migrating.

The coastal areas of China are located at the center of the migration route from East Asia to Australia, and are the throat for migratory birds to and from breeding and wintering areas. Migratory bird habitats are scattered throughout the southeastern coast of China, and currently less than half of the habitats are in a protected state. When migratory birds travel between their breeding grounds in Russia and their wintering grounds in Australia, they must find suitable habitats here to rest and replenish their energy. The number of coastal habitats is crucial for the survival of migratory birds.

Migratory bird migration pathways and coastal habitats, mapping @ Lepersil/visualizing planets

The abundant resources around the coastline also attract people to settle, develop, and make a living here. The ten coastal provinces account for 15% of the land area, but they carry over 40% of China's population and contribute 60% of the country's GDP. Among the top ten provinces in terms of GDP, coastal provinces occupy six seats.

The ocean has been a channel for trade and cultural exchanges between China and foreign countries since ancient times. Marine trade was initiated in the Spring and Autumn period. Sailors set out from the Liaodong Peninsula, passed through the Korean Peninsula, and sailed to Japan, opening the first overseas route. Nowadays, China has 2007 coastal ports, and the cargo throughput of ports above designated size has reached 9212.94 million tons, ranking among the top in the world.

Distribution of ports above coastal scale, mapping @ Lepersil/visual planet

In China, bedrock coast is mainly distributed in the southern end of Liaodong Peninsula, Shanhai Pass Huludao, Shandong Peninsula, Zhejiang, Fujian and Taiwan. Among them, the Liaodong Peninsula protrudes between the Bohai Sea and the Yellow Sea, and is mostly composed of dense and hard ancient Quartzite; The Shandong Peninsula is inserted into the Yellow Sea and is mostly shaped by granite; The coastal sections of eastern Zhejiang and northern Fujian to the south of Hangzhou Bay are mostly composed of Igneous rock; The bedrock coasts of southern Fujian, Guangdong, and Hainan are mostly formed by granite and basalt.

From the Planet Research Institute

The Sea Erosion Arch Bridge in Dalian Jinshitan

On the west coast of the Bohai Sea - Liaodong Bay, Bohai Bay, Laizhou Bay, and the Jiangsu coast on the west coast of the Yellow Sea, you will see a sediment accumulation coast. It is vast and magnificent. The mudflat between high and low tide lines can be more than 10km wide, and generally 3-5 km wide. This is the muddy plain coast. Unlike sandy coasts dominated by wave action, these coasts are generally located in coastal areas with abundant sediment sources and more pronounced tidal effects. In shallow water areas around the world, tides transport a large amount of fine-grained sediment - silt, clay, organic debris... These fine-grained substances ranging from 0.05 to 0.001 millimeters form vast and flat tidal flats on muddy plain coasts.

From the Planet Research Institute

Yancheng mudflat in central Jiangsu

Sandy and gravel coasts are mainly developed on both sides of river inlets. Rivers provide abundant sand sources for sandy and gravel coasts, and waves push the sediment into the sea to accumulate on the shore, forming charming beaches. The sandy and gravel coast best meets people's need to get close to the sea, with delicate beaches and blue seawater, making it a standard configuration for people to spend summer. The sand dune coast in China is not long, but it is widely distributed, such as between Qinhuangdao and Beidaihe along the eastern coast of Hebei, and between the Yanghe River mouth and the Luan River mouth; Penglai and Weihai in Shandong Peninsula; Some places in Zhanjiang, Guangdong and Hainan Island.

From the Planet Research Institute

Fuzhou Pingtan Elephant Trunk Bay, from the Institute of Planet Research

The coastline, as the interaction between the two natural plates of the Earth - the continent and the ocean, has a rich landscape that far exceeds our imagination.

Walking slowly along the coast, you will find that the color of the seawater changes with the weather and light, and each time the seawater rushes ashore, it will "bloom" with different waves; Reef is also considerable. The sea erosion column, Sea cave, sea erosion cliff formed by sea erosion are strange in shape and full of magic color; You will also encounter creatures that inhabit the coastal zone, such as shellfish, algae, fish, birds... They will make you dizzy and overwhelmed.

The Queen's Head Mushroom Stone in Yeliu Geopark, Taiwan, from the Institute of Planet Research

Of course, over the past 70 years, China's mainland coastline has undergone significant changes, with more and more natural shorelines being replaced by industrial shorelines such as reclamation and docks. While achieving rapid development, human activities such as excessive reclamation and aquaculture, intensive port and dock construction, and land reclamation have brought a series of ecological and environmental problems to the coastline, affecting the balance of the ecosystem. How to protect resources and the environment while enjoying them is an eternal issue that accompanies human development.