FW: Growing limestone sand with electricity to save beaches and islands
Tom Goreau
October 8, 2025
Electrifying coralline algae to regenerate white sand beaches and eroding islands against climate change
Thomas J. F. Goreau, PhD
President, Global Coral Reef Alliance
ABSTRACT
Increasing global sea level rise and storm strength, caused by global warming from fossil fuel Green House Gases (GHGs), are accelerating beach erosion worldwide, simultaneously with an increasing global crisis of suitable sand availability. Coralline Green and Red algae, especially Halimeda, are the most productive source of limestone in the ocean, and generate most tropical white beach sand, naturally replenishing sand inevitably lost to erosion. A single species, Halimeda opuntia, is the most important source of tropical white beach sand, having ideal genetic, physiological, and ecological adaptations for large-scale cultivation to regenerate beaches. With Biorock electric reef technology growing coralline algae directly in front of eroding beaches, while also protecting beach sand from wave erosion, natural white limestone sand beaches have been grown at record rates without any dredging, pumping, or dumping of sand. Examples from the Caribbean, Indian Ocean, Pacific, and South East Asia are shown. Actively growing beach sand where it is most needed makes sand supply no longer a zero-sum game, reliant on expensive sand shipments, stealing it from other beaches, rivers, or dredging the ocean and damaging coral reefs. Halimeda opuntia sand beaches can be grown around the tropics, and red coralline algae (Maerl) beaches in cold waters. A dozen sites around the world that would immediately benefit from Biorock sand farming technology are discussed. Matching sea level rise by actively growing new coralline algae sand supplies, while simultaneously protecting beaches from erosion using Biorock electric reef technology, creates a completely new strategy to save severely eroding beaches and low islands from sea level rise, with global applications for coastal climate change adaptation.
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