Microplastic chemicals threaten coral reproduction in hawaiian waters

Under the new moon’s glow in Kāneʻohe Bay, Oʻahu, millions of coral egg and sperm bundles rise from the reef in a spectacular display of nature’s timing. But this ancient reproductive ritual now faces a modern threat: microplastic pollution that may disrupt the delicate chemical signals guiding coral reproduction.

Hawaii’s location near the Pacific Garbage Patch means these floating reproductive bundles increasingly share waters with microplastics and their toxic chemical leachate. While most research has focused on how adult corals are affected by ingesting plastic particles, University of Hawaiʻi at Mānoa coral biologist Keiko Wilkins examined something different—how plastic chemicals impact the earliest, most vulnerable stages of coral life.

Her groundbreaking study, published in Frontiers in Marine Science, reveals that plastic leachate affects coral reproduction in complex ways, with different impacts on fertilization versus larval settlement. “The effects that we’re seeing on the fertilization and the effects that we’re seeing on the larvae settling are very different,” Wilkins explained.

This research adds another layer of concern for coral reefs already struggling with bleaching from rising ocean temperatures, ocean acidification, and pollution. The findings suggest that microplastic contamination could be undermining coral reproduction at its most critical stages, potentially hampering reef recovery efforts. As coral spawning depends on precise chemical cues and lunar timing, any interference with these natural processes could have cascading effects on reef ecosystems that millions of marine species call home.