British Scientists Discover a Chemical That Helps Deep-Sea Fish Maintain Water Molecular Networks in Cells to Withstand Pressure.
Pseudoliparis swirei filmed at a depth of about 8,000 meters in the Mariana Trench. (Video: UW)
In the Mariana Trench, the deepest part of the Earth’s crust, water pressure reaches up to 8 tons per square inch. How do fish and many other species survive in such a lethal environment? According to a new study published in the journal Communications Chemistry on September 28, the secret lies in a naturally occurring chemical in their cells.
Normally, under standard atmospheric pressure, water molecules in living cells form a tetrahedral-like network. If that network changes shape—such as through the impact of external pressure—then crucial biochemical processes cannot occur within the cells. When this happens on an organism-wide scale, it can lead to death.
Led by Dr. Harrison Laurent and Professor Lorna Dougan, scientists at the University of Leeds in the UK discovered that within deep-sea organisms, a molecule called TMAO (trimethylamine N-oxide) keeps the molecular network of water in their cells from deforming. The deeper the animals’ habitat, the higher the TMAO concentration in their cells.
Pseudoliparis swirei in the Mariana Trench.
In an experiment at the STFC Rutherford Appleton Laboratory in Oxfordshire, the research team fired neutron beams at samples of water with and without TMAO stored at high or low pressure. The results showed that the hydrogen bonds in water molecules without TMAO were deformed under pressure, and the molecular network as a whole became tightly compressed. However, in samples with added TMAO, the hydrogen bonds remained very strong and stable, while the network structure was maintained.
“TMAO provides a structural anchor that allows water to withstand the extreme pressures it encounters. This discovery is significant because it helps us understand the processes through which organisms have adapted to survive in harsh ocean conditions,” emphasized Laurent.
Based on the experimental results, the research team was also able to develop a model to predict the necessary levels of TMAO in the cells of organisms living at specific depths in the ocean.
“Our research bridges the gap between water under pressure at the molecular level and the remarkable adaptability of marine organisms, those that thrive under high pressure in the dark depths of the ocean,” Dougan added.
