Precision Light Attenuation to Reestablish Coral Spawning Synchrony

Abstract

This project investigates the effects of artificial light at night (ALAN) on synchronized spawning of reef-building corals in the Chaojing Bay Marine Protected Area, northeastern Taiwan. It also aims to establish a coastal restoration framework based on the recovery of natural coral spawning rhythms. Preliminary experiments indicate that even low-intensity artificial light can disrupt coral responses to natural darkness and lunar cycles, thereby reducing spawning synchrony. This disruption may subsequently reduce fertilization success and larval recruitment, with implications for coral population persistence and reef resilience.

We will integrate gamete development monitoring, spawning observations, and larval recruitment surveys to compare coral reproductive responses before and after improvements to the nighttime light environment. This comparison will determine whether reducing nighttime artificial light can restore synchronized spawning and increase larval recruitment. The results will provide a scientifically grounded, practical, and scalable framework for coastal light management and coral reef restoration.

Methodology and Implementation Steps

1. Establishment of Underwater Light Monitoring System
   A long-term underwater light monitoring framework is established in the Chaojing Bay Marine Protected Area. A self-developed underwater spectral monitoring system is deployed to quantify artificial light intensity, spectral composition, and natural lunar illumination. These measurements provide baseline information on nighttime light environments and their potential influence on coral reproductive processes.
2. Monitoring of Coral Reproductive Status
   During the coral spawning season, reef-building coral colonies are regularly monitored to evaluate gamete development and reproductive maturity. These observations provide essential information on coral reproductive cycles and the relationship between spawning patterns and environmental cues, including lunar cycles.
3. Observation of Spawning Synchrony and Data Collection
   Nighttime underwater observations are conducted in combination with a customized coral egg collection system to record spawning timing, gamete release, and colony-level spawning synchrony. These data are used to evaluate how artificial light exposure influences coral reproductive rhythms and spawning coordination.
4. Precision Light Attenuation and Habitat Restoration
   Based on underwater light assessments, targeted precision light attenuation strategies are implemented to reduce artificial light disturbance. Approaches include shading, reducing light intensity, and adjusting light direction while maintaining necessary coastal operational requirements. The effectiveness of these measures is evaluated through continuous environmental monitoring.
5. Assessment of Larval Settlement and Ecological Recovery
   Biomimetic molded settlement plates developed by the research team are deployed to quantify coral larval settlement and juvenile recruitment. These measurements are used to evaluate whether improved nighttime light conditions enhance coral population recovery and ecosystem restoration potential.
6. Data Integration and Restoration Framework Development
   Environmental light conditions, gamete development, spawning synchrony, and larval recruitment data are integrated to compare ecological responses before and after restoration. The results will support the development of a science-based and scalable framework for coastal light pollution management and coral reproductive rhythm restoration.

Innovation and Cross-Disciplinary Collaboration

本計畫提出「精準降光修復珊瑚同步產卵」策略，將夜間光環境管理納入珊瑚生態復育架構，從恢復珊瑚自然生殖節律與族群更新功能的角度，建立新的保育模式。研究於潮境海灣海洋資源保育區執行，具備長期生態監測與保育示範的重要價值。計畫結合海洋生態、光學監測與環境管理，並與國立海洋科技博物館合作，整合科學研究、保育實務與環境教育資源，建立可複製的沿岸光害治理與珊瑚保育模式。

Expected Results and Contributions

本計畫預期建立以科學監測為基礎的精準光環境管理模式，揭示人類夜間活動與珊瑚生殖節律之間的關聯，並提供兼顧沿岸發展需求與海洋保育的調節策略。透過量化光環境與珊瑚反應，本研究將實現對自然生態條件的精準調整，在維持人類活動與產業運作的同時，降低對珊瑚繁殖的干擾。成果將作為海洋資源保育區光害管理、永續沿岸利用及生態友善發展的重要科學依據。