New progress has been made in the study of "Millennium Development Pattern of Coral Reefs in the Northern South China Sea"

Recently, Chen Tiantian, a researcher in the Key Laboratory of Coral Reef and Environmental Recording in the Key Laboratory of Marginal Sea and Ocean Geology of the Chinese Academy of Sciences, and Professor Zhao Jianxin of the University of Queensland, Australia, have made the latest progress in the study of coral reef development patterns, and the relevant research results have been published in science of The Total Environment (Journal of Total Environmental Science).

The Earth has entered a new era characterized by "significant changes in the Earth system by human activities", the "Anthropocene". In contrast to oceanic coral reefs far from the mainland, in addition to being subject to the stress of climate change, in addition to being subject to strong human interference, most of them show a sharp trend of degradation, that is, gradually transitioning to (or have become) "marginal reefs". The Northwest Pacific Ocean (including Southeast Asia and the northern part of the South China Sea) and the Atlantic Caribbean Sea are two typical regions in the world, but the study of coral reefs in the South China Sea is far lower than that in the Caribbean Sea, mainly due to the lack of long-term observation and historical data and data accumulation, which restricts a comprehensive and in-depth understanding of the degradation and development history of coral reefs in the South China Sea and its "causes".

Through high-precision U-Th radioisotope dating technology, the researchers determined about 100 bulk and branch coral samples on Weizhou Island in the northern South China Sea, and analyzed the age of death and species, revealing the evolutionary history of coral reefs in the past hundred years, and found that a large number of coral deaths and degradation of coral reefs had actually occurred as early as 1950, far earlier than the records of modern observations, and coincided with the "The Great Acceleration of the Great". Studies have revealed that the frequency and extent of coral death in the northern South China Sea have gradually increased since the 1980s, and the main time of death and community collapse of staghorn corals occurred in 1960, 1984 and 1998, and there were trends such as sharp declines in coral cover and changes in dominant species. Based on the distribution curve of coral death ages, the researchers linked the peak of coral death with specific extreme weather events (such as winter cold events, El Niño high temperature events) and human activities (such as fishing, mariculture, agricultural reclamation, tourism development, infrastructure construction) that occurred at various times in the past 50 years, and identified the "causes" and pointed out that the damage of human activities in the region far exceeded the impact of climate change.

In addition, the study also found that the sedimentation of paleo coral reefs on land (uplifted) is mainly composed of staghorn corals, and its dating distribution since the Late Holocene (3000 yr BP) indicates that the reef area on the northern coast of the South China Sea for thousands of years is likely to be the top ecological model of staghorn corals as the dominant species, and in just 50 years after the "Great Acceleration", human activities have completely changed the development pattern of coral reefs that have maintained for thousands of years, and gradually "marginalized". Based on the results of the study, the researchers targeted Prof. "The wicked problem of China's disappearing coral reefs" by Hughes et al., see Hughes, et al. 2013, Conservation Biology) gave scientific answers and gave scientific advice on how to effectively protect and restore coral reefs.

This research was supported by the National Natural Science Foundation of China (41676049, 41476038), the Guangdong Provincial Laboratory of Southern Ocean Science and Engineering (Guangzhou) Team Project (GML2019GD0206) and the Guangdong Provincial Natural Science Foundation of China (2018A030313142).

Guangzhou Daily all-media reporter Long Kun Correspondent Li Shu Guangzhou Daily all-media editor Li Fenghe