Information Times (Reporter Cheng Xiaozhen, Correspondent Li Shu) Recently, Chen Tianran, a researcher from the Coral Reef and Environmental Recording Group of the Key Laboratory of Marginal Sea and Ocean Geology, Chinese Academy of Sciences, and Professor Zhao Jianxin of the University of Queensland, Australia, have made achievements in the study of coral reef development patterns. The latest progress, relevant research results were published in the "Journal of General Environmental Science").
The dead staghorn and pontoic corals are shocking; each U-Th peak corresponds to the death of a large number of corals that year. Photo courtesy of the correspondent
Most of the nearshore coral reefs are showing a rapid trend of degradation
The earth has entered a new era, the "Anthropocene", which is characterized by "significant changes in the earth system by human activities". According to reports, compared with the oceanic coral reefs far away from the mainland, in addition to the stress of climate change, the near-shore coral reefs are also superimposed by the strong interference of human activities, and most of them show a trend of rapid degradation, that is, they gradually transition to (or have become) "marginal coral reefs" ".
It is understood that the Northwest Pacific (including Southeast Asia and the northern part of the South my country Sea) and the Atlantic Caribbean Sea are two typical regions in the world, but the research on coral reefs in the South China Sea is far lower than that in the Caribbean Sea. This is mainly due to the lack of long-term observations and accumulation of historical data and data, which restricts a comprehensive and in-depth understanding of the degradation and development history of coral reefs in the South China Sea and their "causes".
Mass coral die-off occurred as early as around 1950
Using high-precision U-Th radioisotope dating technology, the researchers measured about 100 massive and branched coral samples from Weizhou Island in the northern South China Sea, and analyzed the death age and species, revealing the evolution of coral reefs in the past 100 years. history. The study found that the massive death of corals and the degradation of coral reefs actually occurred as early as around 1950, far earlier than the records of modern observations, and coincided with the "Great Acceleration of the Anthropocene".
The study also revealed that the frequency and extent of coral mortality in the northern South China Sea has gradually increased since 1980. The main periods of staghorn coral death and community collapse occurred in 1960, 1984, and 1998, with trends such as sharp reductions in coral cover and changes in dominant species.
Based on the distribution curve of coral death years, the researchers correlated peak coral mortality with specific extreme climate events (such as winter cold events) and human activities (such as fishing, mariculture, agricultural reclamation, tourism development, infrastructure Construction) one by one, and found the "cause": the destruction of human activities in this area far exceeds the impact of climate change.
In addition, the study also found that the ancient coral reef deposits on land (uplifted) were mainly composed of staghorn corals, and their ages were distributed since the late Holocene, indicating that the northern fringing reef area of the South China Sea is likely to be dominated by staghorn corals for thousands of years. In just 50 years after the "Great Acceleration", human activities have completely changed the developmental pattern that coral reefs have maintained for thousands of years, thereby gradually "marginalizing".
Based on the results of the study, the researchers made a scientific answer to the "Question of Coral Reefs in the South China Sea" and gave scientific advice on how to effectively protect and restore coral reefs. It is reported that this research was funded by the National Natural Science Foundation of China, the Southern Ocean Science and Engineering Guangdong Laboratory (Guangzhou) team project and the Guangdong Provincial Natural Science Foundation.
Source: Information Times