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The first type of experimentation involved the assessment of marine invertebrate survivability and colonization within glass cullet mixtures. Experimental bioassays were divided into five, three-container series (total of 15), with each series testing 23 kg of proportioned natural sand/glass cullet mixtures.

Photograph 1. Experimental bioassays containing marine life and glass cullet

Crabs, mollusks, urchins, and microscopic organisms, were introduced to each bioassay and analyzed through direct observations. After a two-month exposure to recycled glass cullet matrices, it was determined that an artificial cullet substrate does not adversely affect macrofauna habitation or microfauna colonization. Of particular note, was the use of the cullet as defensive camouflage by the test crustaceans and mollusks. In order to shield themselves from predators or direct UV light, the sargassum and blue crabs would thrust their carapaces backward into the cullet until they were completely covered. These experiments indicate that recycled glass cullet is a biologically benign material that can be used to mitigate development of erosional hot spots in nourished beaches. By doing so, a proactive recycling program can be initiated to protect one of Earth’s most valuable resources, the coastline.

Photograph 2. Variable sea urchin, Lytechinus variegates, on a recycled glass cullet substrate.

Photograph 3. Example of macrofauna, blue crab (Callinectes sp.), introduced to a 100% cullet substrate.

Photograph 4. Blue crab (Callinectes sp.) using recycled glass cullet as camouflage.

Photograph 5. Sargassum crab (Portunus sayi) using recycled glass cullet as camouflage. This defensive measure caused no adverse effect to the crustaceans.

Photograph 6. Interstitial copepod moving within 100% glass cullet at 400x. Colonization of microfauna was observed in all the experimental treatment series.
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