双色鹦嘴鱼群在安达曼海的珊瑚礁上向水中排泄沙子

ish sand production is visible in real time as a school of Ember Parrotfish (Scarus rubroviolaceus) defecates pulverised coral into the water column on this Andaman Sea reef. Each fish grinds swallowed limestone in a specialised pharyngeal mill, expelling the indigestible calcium carbonate as fine white sand while absorbing the algae within. The school moves as one unit between coral patches, repeating the process reef wide. 4K, wide angle, vertical medium shot, scuba diver POV. Andaman Sea, Krabi Province, Thailand.