This flows into a network of branched tubes called the respiratory tree, which takes in oxygen from the seawater. (newscientist.com)
Most of the carbon - 14 wound up in the respiratory tree, with very little in the digestive system, suggesting it was being taken in through the anus and respiratory system. (newscientist.com)
But the respiratory tree can take in more than oxygen, says Richard Strathmann of the University of Washington in Friday Harbor — it also takes up dissolved organic compounds. (newscientist.com)