Facts

Bioherms, Stromatolites aka Great Salt Lake Coral

Bioherms at Hat Island

Bioherms cover about 10 percent of Great Salt Lake's bottom. A bioherm is a mound of calcium and magnesium carbonate deposits produced by the blue-green algae Apthanothece packardii. Bioherms dominate shallow water and shore areas where wave activity is strong—they can be as small as a few inches and as tall as 3–4 feet and 12 feet in diameter! Stansbury Island, the northwest end of Antelope Island, and the southwest side of the Promontory Range are fantastic spots to find bioherms.