Respiratory and acid-base physiology of the purple sea urchin, Strongylocentrotus purpuratus, during air exposure: presence and function of a facultative lung. From: The Biological Bulletin | Date: August 1, 2002| Author: Burnett, Louis; Terwilliger, Nora; Carroll, Amy; Jorgensen, Darwin; Scholnick, David | COPYRIGHT 2002 Marine Biological Laboratory. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan.  All inquiries regarding rights should be directed to the Gale Group.Copyright information

Upon exposure to air (emersion), the purple sea urchin Strongylocentrotus purpuratus releases an "emersion fluid" from its esophagus. Release of this fluid causes air to appear within the test (or calcareous theca), most likely inside the intestine. The air space is large, occupying 33.5% of the volume of the intrathecal space. The intestine containing air forms a facultative lung and contributes to the oxygenation of the perivisceral coelomic fluid (PCF) during emersion. During emersion, t...