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Tag: denticles

Climate Change Killing the Environment Part 1000000 – How Ocean Acidification is Damaging Shark Scales

What is Ocean Acidification and How Does it Affect Sea Life?

During Climate Change the amount of carbon dioxide (CO2) in the atmosphere increases which also increases the amount of CO2 in the ocean. This CO2 which dissolves in the ocean combines with water to create carbonic acid. This added acid lowers the pH of the water which therefore acidifies the seawater. When the pH is lowered, the acid harms organisms like coral or other calcium-based structures because the acid starts to break down their calcium. 

Coral Facing the Effects of Ocean Acidification in the Great Barrier Reef

How Does This Affect the Sharks? 

If you look closely at most fish you will see that they have flat scales but Sharks, on the other hand, have scales that resemble teeth and are called denticles. Unlike other fish, Shark denticles cover their entire bodies and influence the way they swim. The denticles on Sharks are also made up of compounds containing calcium which is sensitive to a lower pH. Sadly because of this Sharks like corals will suffer from the effects of Ocean Acidification.  

Shark Denticles under a Microscope

The Study 

The article by the Heinrich-Heine University Dusseldorf focuses on the study which was performed by the research team from two South African research institutions the University of Duisburg-Essen and Heinrich-Heine University. They studied both puffadder shysharks who live on the bottom of the Atlantic Ocean off the coast of Cape Town and ones who lived in the DAFF Research Aquarium in Cape Town. For several weeks the researchers kept one group of sharks in a controlled seawater environment and another group in acidic water. After this time the researchers compared the denticles of these two groups and noticed that on average about 25% of the acidic water shark’s denticles had been damaged while in the controlled group the percentage was less than 10%. The acidic group’s denticles were damaged where it affected their ability to swim. Furthermore, Shark’s teeth are made of a similar compound to their denticles so the acidity also affected their food intake. 

Puffadder Shyshark on the bottom of the ocean floor

How Are Sharks Combatting 

Researchers continued their study and analyzed the blood of the animals in the acidic and normal environments. They discovered that the blood of sharks in the acidic environments had higher concentrations of both CO2 and bicarbonate. Interestingly, as sharks have more bi-carbonate in their blood this prevents the blood from becoming too acidic. This shows that sharks have acid-base regulatory processes for adapting to environmental changes. Although Sharks have a way to combat these changes not all animals have ways to protect themselves. So as more climate changes issues happen it is vital that we as humans are aware of the harm and strive to find ways to reserve its effects. 

Shark Skin is Impressive!

George Lauder from Harvard University, USA, explains that the fish have long inspired human engineers, but more recently attention has focused on how the fish’s remarkable skin boosts swimming.” The Ridges called denticles that cover the shark helps it swim faster.The denticles not only increase speed, they also “improve thrust.” When sharks swim, the water goes through their furrows, reducing friction and ultimately helping them swim faster.

“The shark’s skin is so rough that contact with it can injure prey.” The coarse denticles point facing the tail so if you were to rub your hand down towards the tail it would feel smooth. Oppositely if you were to rub towards shark’s head it would feel very rough.

“Sharkskin is well adapted for moving through water at high speeds, so engineering a similar coating could be useful in making wind and water turbines run more efficiently. To do that, scientists need to understand exactly how denticles work.” A study at Harvard showed that denticles help the shark move 12% faster in comparison to a shark who does not have denticles!

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