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ORIGINAL RESEARCH article

Front. Mar. Sci.
Sec. Coastal Ocean Processes
Volume 11 - 2024 | doi: 10.3389/fmars.2024.1460450

Observations of waves and currents on the fore-reef and reef flat of a coral reef atoll in the South China Sea

Provisionally accepted
Renfu Fan Renfu Fan 1,2Hao Wei Hao Wei 3Yanfang Mai Yanfang Mai 4*Lin Zhang Lin Zhang 1,2*Jitao Yu Jitao Yu 1,2*Daoru Wang Daoru Wang 1,2*
  • 1 Hainan Academy of Ocean and Fisheries Sciences, Haikou, China
  • 2 Yazhou Bay Innovation Institute of Hainan Tropical Ocean University, Sanya, China
  • 3 School of Marine Science and Technology, Tianjin University, Tianjin, China
  • 4 College of Computer Science and Technology, Hainan Tropical Ocean University, Sanya, China

The final, formatted version of the article will be published soon.

    Understanding the wave and current conditions of coral reef ecosystems is essential for maintaining their health, as many reef processes are controlled by these hydrodynamic conditions. In this study, high-frequency measurements of tides, waves, and currents were made using acoustic, electromagnetic, and pressure instruments over a 28-d period on the fore-reef and reef flat of a coral reef atoll in the South China Sea. The research revealed wave transformation, tidal and wave modulation of flow, and wave setup conditions for the first time at this typical atoll. Three large wave processes dominated by gravity waves (GWs) are observed in the fore-reef. The GWs are significantly attenuated on the reef flat, whereas infragravity (IG) waves strengthened. The tidal modulation of GWs and IG waves on the reef flat is significant when the incident wave height exceeded 1 m. In the fore-reef, the modulation of progressive tidal waves and large waves leads to relatively stronger upper-layer currents, and weak near-bottom currents are primarily attributed to the dissipation of tidal wave energy by the rough coral terrain. In calm conditions, flow variations on the reef flat are modulated by tides, thereby allowing seawater flow to pass through the reef flat during spring tides. Conversely, during periods with large waves, tidal modulation of flow on the reef flat is less significant, and the cross-reef flow velocity increases with increasing incident wave height. The occurrence of wave setup on the reef flat enhances cross-reef flow towards the lagoon. The wave setup is positively linearly correlated with the incident wave height. The magnitude of wave setup is associated with the distance between the measurement sites on the fore-reef and reef flat.

    Keywords: coral reef, waves, Currents, Reef flat, South China Sea

    Received: 06 Jul 2024; Accepted: 26 Aug 2024.

    Copyright: © 2024 Fan, Wei, Mai, Zhang, Yu and Wang. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence:
    Yanfang Mai, College of Computer Science and Technology, Hainan Tropical Ocean University, Sanya, China
    Lin Zhang, Hainan Academy of Ocean and Fisheries Sciences, Haikou, China
    Jitao Yu, Hainan Academy of Ocean and Fisheries Sciences, Haikou, China
    Daoru Wang, Hainan Academy of Ocean and Fisheries Sciences, Haikou, China

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