Journal of Tropical Oceanography ›› 2025, Vol. 44 ›› Issue (3): 206-216.doi: 10.11978/2024132CSTR: 32234.14.2024132

• Marine Environmental Science • Previous Articles     Next Articles

Changes and controlling factors of seawater phosphorus in Weizhou Island over the past 30 years: Insights from high-resolution coral records

CHEN Yuyue1(), JIANG Wei2(), YANG Haodan2, YU Kefu2   

  1. 1. College of Marine Science and Technology, China University of Geosciences, Wuhan 430070, China
    2. Guangxi Laboratory on the Study of Coral Reefs in the South China Sea, School of Marine Sciences, Guangxi University, Nanning 530004, China
  • Received:2024-06-27 Revised:2024-07-29 Online:2025-05-10 Published:2025-06-04
  • Contact: JIANG Wei
  • Supported by:
    National Key Research and Development Program of China(2023YFF0804801); National Natural Science Foundation of China(41976059)

Abstract:

The change in phosphorus (P) content in surface seawater is an important parameter to evaluate the nutrient content of marine ecosystem, and plays a significant role in regulating the evolution of the Earth’s environment. Weizhou Island is the largest and youngest volcanic island in China. The change in surface phosphorus content in seawater over a long time scale is not well documented, and the influencing factors remain unclear. Coral skeleton P/Ca is a reliable index for retrieving seawater phosphorus content and is widely used to reconstruct the high-resolution history of seawater P content. In this study, continuously growing corals from northwest Weizhou Island were taken as the research object, and an age framework was established from 1985 to 2015 based on coral oxygen isotopes to reconstruct the P/Ca change history of surface seawater in monthly resolution from 1985 to 2014. The results showed that the coral P/Ca value varied greatly in different years and seasons, with low P/Ca values observed from 1998 to 2003, generally lower than the annual average. The change in coral P/Ca ratio was highly correlated with the change in monsoon intensity (P<0.05), and the coral P/Ca value increased significantly during the monsoon and typhoon periods, indicating that the sea ~surface wind was the main factor controlling the change in seawater P content in this region. Additionally, volcanic eruptions, oil spills, and tourism can also cause a temporary increase in P content, but the effects are limited. However, there was no significant correlation between the inter-annual variations of rainfall and changes between wet and dry seasons and the P/Ca values, indicating that terrigenous materials had limited influence on the change in P content in seawater.

Key words: Weizhou Island, phosphorus, coral reefs, geochemistry

CLC Number: 

  • X145