Oceanography

Focusing on the question of "where does the water on the coast go during the low tide", this paper introduces the related concepts of tides and intertidal zones, and explains the principle that the tides are formed by the tide-generating force of the moon and the sun. The water at the low tide does not disappear into thin air, but only temporarily flows to nearby low-tide areas and flows back at high tide.

This paper focuses on the problems of large population and cities in the Estuary Delta. It points out that the Estuary Delta has gradually developed large cities and urban agglomerations due to its livable conditions such as flat terrain, fertile land, convenient waterways, and rich resources. At the same time, the region's ecological environment is fragile and it is one of the areas with the greatest pressure of ecological crisis.

Focusing on the question of "why do estuarine deltas have different shapes", this paper explains that the formation of estuarine deltas is affected by various factors such as river sediment concentration and estuarine hydrodynamic forces. There are significant differences in their size, geometry and shoreline shape. They are mainly divided into three types according to their shapes: fan shape, bird foot shape, and pointed shape, and the formation reasons and typical representatives of various deltas are introduced respectively.

Focusing on the question of why there are deltas in almost all estuaries entering the sea, this paper introduces the origin of the name of the delta, explains the formation of the estuarine delta, explains that the delta includes both land and underwater parts, and lists the situation and reasons for not forming deltas in a few estuaries such as the Amazon River and the Qiantang River.

Focusing on the question of "Why do there are sand dunes on the coast like deserts?" This paper introduces the distribution of coastal sand dunes, clarifies the conditions such as rich sand sources, suitable wind conditions, and broad terrain space required for the formation of coastal sand dunes, and explains the specific formation process of coastal sand dunes. It also explains the factors that influence the differences in the development scale and type of coastal sand dune in different regions.

Focusing on the question of "Is the coastline a line?", this paper points out that the coast is not a line but a transitional zone for the interaction between land and the ocean, namely the coastal zone. It introduces the scope of the coastal zone, the divided supratidal zone, intertidal zone, and the characteristics of the three areas of subtidal zone, as well as the ecological environment characteristics of the coastal zone and the importance of protection.

This paper focuses on the problem that the Southern Ocean can absorb a large amount of carbon dioxide. It explains that the core reason is that the wind and waves formed by the strong westerly winds prevailing all year round stir the sea surface, causing carbon dioxide in the atmosphere to dissolve in the surface seawater. At the same time, it introduces that the carbon dioxide absorbed by the Southern Ocean is only 9%, and most of it will be transported north to the subtropical sea area under the combined action of ocean currents and vortices. Part of the carbon dioxide will enter a depth of 1000 meters with the Antarctic surface water sinking near 55° south latitude. Then as the ocean currents move north near the equator, a counterclockwise vortex with an average diameter of about 100 kilometers also plays an important role in the sinking of carbon dioxide

This article focuses on the question of why fishing grounds are mostly built in areas where the sea water is rising. It points out that upwelling can bring nutrients from deep seawater to the surface and promote the reproduction of plankton to attract fish. The primary production, plankton production and fish production in the upwelling area are much higher than those in non-upwelling areas. The catch in the upwelling area, which accounts for only 0.1% of the world's ocean area, accounts for half of the world's total marine fish production. Russia's Thousand Islands Fishing Ground, Many famous fishing grounds such as Canada's Newfoundland Fishing Ground, Peru Fishing Ground, and China's Zhoushan Fishing Ground are built in waters with significant upwelling.

Focusing on the question of why the sea water in some places rises and the sea water in some places sinks, this paper introduces the principle and related examples of the joint action of stroke and geostrophic deflection forces in coastal waters to form upwelling and downwelling currents. It also explains the mechanism and typical cases of counterclockwise and clockwise atmospheric vortices in open waters that cause the sea water to rise and sink respectively.

This article focuses on the question of "why can the sea carry messages", introducing the QQ mailbox drift bottles, introduces the historical origin of the drift bottles, and explains that the sea can carry messages because there is a constantly circulating and intertwined ocean current circulation system on the surface of the global ocean. At the same time, it explains that the uncertainty of the drift bottle and the probability of being successfully picked up are extremely low

Focusing on the question of "Where did the Kuroshio come from", this paper introduces the origin of its name, physical characteristics, impact on fisheries and East Asian coastal climate, as well as its origin in the equatorial Pacific Ocean's flow path, snake-shaped large curved characteristics and other related knowledge.

Focusing on the question of "Are currents a river in the sea?" This paper introduces the discovery process of the Gulf Stream, the basic characteristics of the Gulf Stream and the Kuroshio, explains the formation of currents and the operating mechanism of the global ocean circulation system, explains the causes of deep currents and the important role of the current system, and points out that changes in currents may have considerable impact on the global climate.