Why don’t whales get the bends, ask scientists in articles in ScienceDaily 25 April 2018 and Proceedings of the Royal Society B 25 April 2018 doi: 10.1098/rspb.2018.0482.
Ever since decompression sickness was known about in human divers scientists have been intrigued as to why diving animals such as whales, dolphins and sea turtles seem to be immune to it.
Now researchers at Fundacion Oceanografic, Spain, and Woods Hole Oceanographic Institution, USA, have surveyed the research on how diving animals breathe and developed a new theory as to why air breathing mammals and reptiles can survive rapid deep dives and re-surfacing without getting decompression sickness (“the bends”).
Decompression sickness is caused by nitrogen from the air in the lungs being absorbed into the blood stream, and then coming out of solution and forming bubbles before it can diffuse out of the blood back into the lungs. Diving animals have a very flexible chest structure that enables their lungs to compress, but scientists were not sure how this helped avoid the nitrogen problem. The researchers studied CT scans of a deceased dolphin, seal and pig taken in a compression chamber that simulated a deep dive. The lungs of the marine mammals formed into two regions – one became collapsed and the other contained most of the air.
The researchers suggest the animals direct most of their blood flow through the collapsed region where it is not exposed to the air thereby minimising the absorptions of nitrogen into the blood. Previous studies have found structures in the blood vessels of their lungs that would facilitate this. The air-filled regions still absorb some oxygen and release carbon dioxide, but nitrogen dissolves at a different rate to these gases so less nitrogen is absorbed into the blood. The separation into air filled and collapsed regions did not occur in the pig.
Daniel García-Parraga of the Fundacion Oceanografic said this mechanism would prevent whales from taking up too much nitrogen, but more research is needed to confirm the theory. The researchers also suggest that this system may fail during extreme stress, and this may explain why some stranded whales have been found to have gas bubbles in their tissues.
Editorial Comment: This ongoing research is yet another serious challenge to the theory that a land-dwelling animal, with a breathing system well suited to living on land, (textbooks have often favoured cows), evolved into a creature that can live in the sea, but still breathe air. If stress causes whales, which are well suited to the marine life, to get the bends, what must have happened to any half-evolved creature that accidently dived too deep before it had fully evolved? Evolution is a process of struggle and competition so there would have been plenty of stress as a land animal struggled to become a deep diving marine animal.
The more we learn about how well marine mammals and reptiles are designed for their ocean-going life, the sillier and more speculative evolutionary theories are. It is far more sensible to believe the Biblical record of Genesis, which tells us God made sea creatures as fully functioning creatures to reproduce after to their own kind.
Genesis also clearly denies the story that land dwelling mammals and reptiles turned into sea creatures. Sea creatures were made on the fifth creation day, whilst land animals were made on the sixth day. This is one of a number of flat contradictions between Genesis and evolution in the order of origins of living things. Those who want to compromise the Bible with evolutionary theory should take note of this, and decide whose authority they are going to submit to – the word of God who was there, or the ever changing speculations of people who were not.
Evidence News vol. 18, No 4
2 May 2018
Creation Research Australia
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