File photo taken on May 13, 2015 shows the workboat of a Chinese archaeological team for the archaeological work of the Shanhu Island No. 1 shipwreck in the Xisha archipelago in the South China Sea. Photo: Xinhua

Researchers have discovered that sand cays in the Xisha Islands in the South China Sea accurately recorded paleocyclones, or cyclones, in ancient times, according to a recent study published in the journal Geophysical Research Letters.

Researchers from the South China Sea Institute of Oceanology under the Chinese Academy of Sciences and the University of Queensland studied sediments collected from the Xisha Islands, the Xinhua News Agency reported on Sunday.

Sand cays are valuable means of understanding the variability of ancient Holocene tropical cyclones, said the research paper.

The cays' development process was closely related to tropical cyclone activities, which could potentially record paleocyclones. The researchers reconstructed the paleocyclone sequence of the Xisha Islands in the last 500 years and recognized the frequency and strength of the cyclones around the northern South China Sea.

The research shows that frequent cyclones cannot accelerate the accumulation of sand cays, but diversifies the source of the accumulated materials, especially ancient coral samples.

Researchers also found that one sand cay in the Xisha Islands gained two meters in the past 500 years.

The results provide a theoretical basis for further study into the accumulation process and dynamic changes of sand cays, as well as records of the ancient environment.

Chinese scientists are carrying out research in the South China Sea. 

The National People's Congress (NPC), China's top legislature, proposed that a national park being constructed in the South China Sea is needed to better preserve the region's marine ecology. 

Current knowledge on the South China Sea, such as ocean currents and water temperature, is very limited, which makes scientific research in the region more urgent, NPC deputies said earlier.

Xinhua-Global Times