Sharks recycle ammonia from their surroundings

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Sharks recycle ammonia from their surroundings

October 30, 2016 - 10:12
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Researchers discovered that sharks can absorb the ammonia from their surroundings and convert it into urea, so as to maintain the salinity of their tissues.

Sharks absorb ammonia at high rates through their gills

Ammonia is a toxic waste product, produced by the breakdown of amino acids. Instead of being repelled by ammonia (a substance excreted by other animals), sharks actually absorb it at high rates through their gills.

"The amount the shark is able to take in through their gills and convert could amount to almost a third of the nitrogen they need from their diet," said zoologist Chris Wood, from the University of British Columbia.

This ammonia is then used to build up the shark's urea stores. Urea is essential to prevent the shark from drying out in the salty seawater.

He and PhD student Marina Giacomin made the discovery after exposing ten Pacific spiny dogfish to varying concentrations of ammonia ranging from 100 to 1,600 micromoles per litre. The findings of their research was recently published in the Journal of Experimental Biology.

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