Pillar Coral

William Harrigan took this beautiful photo of endangered Pillar Coral. It rises from the sea floor like pillars covered with small hairs. The hairs are actually tiny tentacles that extend from the stalks. Pillar Coral is vulnerable to coral bleaching which occurs in higher ocean temperatures. It's also vulnerable to ocean acidification, which occurs when the ocean's pH decreases due to excessive carbon dioxide, a result from burning fossil fuels.