A VIDEO capturing a large tract of mudflats in Shenzhen Bay has recently gone viral on the internet, with a caption stating that the seawater in Shenzhen Bay was “drying up,” which sparked a heated discussion online.

However, several experts in the fields of hydrology, meteorology and oceanography have clarified that this phenomenon is the result of a normal tidal pattern rather than the “drying up of seawater,” Shenzhen Evening News reported.

In response to the phenomenon of “seawater was drying up” on the Shenzhen Bay online video, a staffer from Shenzhen Bay Park said that this is a normal and natural phenomenon, which is what we call rising and falling tides.

“The footage the netizen provided showed exactly what happened after a low tide, when a large area of mudflats and mud on the beach are exposed, with a large number of crabs and mudskippers coming out. However, the seawater comes back when the tide rises,” the staffer told the News.

Ma Haipeng, a guest lecturer at Shenzhen University’s College of Life Sciences and Oceanography, explained that the tidal pattern that appears along Shenzhen’s shorelines is mixed semidiurnal tide, which means that there are two high tides and two low tides within a 24-hour period, but the high and low tides differ in height.

According to Ma, tides result from the gravitational influence of the moon and sun on Earth’s ocean waters. The tidal range is affected by lunar phases, and the tides with the biggest difference between high and low are called “extreme high tides” and those with the smallest are “extreme low tides.”

The scene in the video happened when there was an extreme low tide in Shenzhen Bay, so it was a natural phenomenon that a large area of mudflats was exposed, Ma said.

Kui Yanwei, a Shenzhen teacher who has won the provincial excellent geography teacher title, elaborated on tides from a geographical perspective.

When Earth rotates, the seawater will rise under the inertial force, and with the influence of the moon’s gravitational force, the seawater will rise further. During each lunar month, two sets of extreme high tides and extreme low tides occur, Kui said.

Shenzhen Bay Park is renowned for its large number of migratory birds and extensive mudflats, making it a beloved spot for many Shenzhen residents. The bay’s tidal movements create an ideal habitat for various waterbirds, as the mudflats exposed at a low tide are especially suitable for them to forage for food.

“Tides not only influence changes in the coastline and water levels, but also impact the distribution and activities of marine life, making them a crucial factor that fishermen pay close attention to while fishing,” Chen Liang, a hydro-meteorological expert, was quoted saying.

Chen said that Shenzhen offers rich coastal resources as a coastal city. He said that those interested in beachcombing usually check the tide schedule on the official platform in advance when planning their itinerary.     (Zhang Yu, Chen Yuying)