Prolonged exposure to high carbon dioxide (acidified) seawater may corrode tooth-like scales (denticles) covering the skin of puffadder shysharks, a study in Scientific Reports suggests. As ocean CO2 concentrations increase due to human activity, oceans are becoming more acidic, with potential implications for marine wildlife. Although the effects of acidified water have been studied in several species, this is the first observed instance of denticle corrosion as a result of long-term exposure.
Lutz Auerswald and colleagues investigated the effects of exposure to acidified seawater in puffadder shysharks. The authors found that in three sharks housed in acidified seawater for nine weeks, 25% of denticles on average were damaged, compared to 9.2% of denticles in a control group of three sharks that had been housed in non-acidic water. They suggest that such corrosion may impair the sharks’ skin protection and open-water sharks’ ability to swim, as denticle surface affects their swimming speed. They also speculate that similar corrosion may occur in sharks’ teeth (which have the same structure and composition as denticles), which may negatively impact their feeding.
However, the authors also found that although exposure was linked with increased carbon dioxide concentrations in blood taken from a total of 36 sharks housed in acidified seawater for different periods of time, concentrations of carbonate also increased. This prevented the blood from becoming more acidic, suggesting that these sharks may be able to adjust to high CO2 conditions during periods of exposure.
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Article and author details
Acid-base adjustments and first evidence of denticle corrosion caused by ocean acidification conditions in a demersal shark species
Corresponding author:
Lutz Auerswald
Department of Environment, Forestry and Fisheries and Stellenbosch University, Stellenbosch, South Africa
DOI
10.1038/s41598-019-54795-7
Online paper
https://www.nature.com/articles/s41598-019-54795-7
~cr comment. PH of 7.3 expected in the year 2300, probably under RCP 8.5
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That SN FB article is at https://www.facebook.com/sciencenews/posts/10157772201641870?__tn__=-R
The sharks had a good run, can’t say I’ll miss them.
Salute!
OMG!!!! Hell!
Can Discovery Channel ever run another “Shark Week”? Maybe we can watch re-runs on History Channel.
Gums asks…
Another something may or not happen sometime science
“Prolonged exposure to high carbon dioxide (acidified) seawater may corrode tooth-like scales (denticles) covering the skin of puffadder shysharks”
And that is why we must stop using fossil fuels and bring the ugly and dirty industrial economy to an end
https://tambonthongchai.com/2019/12/14/ocean-acidification-2019/
Sharks have been around like forever and now they want to claim that they depend on the CO2 concentration. How stupid do they think we and the sharks are? It’s embarrassing.
Organisms have physiological power that handles these weak chemical changes that the alarmists would like to think are fatal to everything on Earth. One has to remember that the world has been through huge climate swings over 600 million years and life is still here.
So a simple question… Did this shark species survive the last time CO2 was this high in the atmosphere?
If yes, then the study is obviously bogus. (I could not find any references to fossils of this shark)
If no, then this is a relatively new species and is adapted to a very specific environment, and therefore more prone to extinction. Generalists generally survive change, specialists often do not (it depends on the change).
So having read the posting, I am wondering if they were dunking the sharks into vats of hydrochloric acid? It says “acidified water”, the last I checked sea water is alkaline.
The paper does not say “acidified water” it says “hypercapnic” and it is achieved in the experiments by adding CO2.
The gills would dissolve long before the scales do.
Puffadder Shysharks – really! I don’t recall seeing any of these when I was growing up around Bremerton, WA [Puget Sound]. These are clearly one of the more common specie of shark! NOT! I must have just missed them. Perhaps they are not common precisely because they show some sensitivity to ocean acidity.
nw sage
From the original article, “Puffadder shysharks are already adapted to a highly variable environment and are restricted in their distribution to the Southern tip of Africa without a possibility of a range shift to mitigate against negative effects of climate change.” So, don’t expect to be seeing them in Puget Sound.
I can’t see how this ”paper” has inspired so much discussion and argument. It’s a pile of junk.
Charles
You commented, “PH of 7.3 expected in the year 2300, probably under RCP 8.5.” Actually it is totally hypothetical, based on the following rationalization: “The hypercapnic level (pH 7.3, expected by year 2300 according to IPCC scenario) was chosen to be below the range of what occurs regularly during upwelling and taking into account that pH levels are usually well below the global average pH of 8.1 in the BCLME.” That is, they are extrapolating 200 years into the future to discern what might happen to a creature adapted to acute decreases in pH, if the conditions were to become chronic and worsen. So, if definitely is a worst-case scenario.
Fresh water ph is normally in the acidic range ie 7.0
Therefore bull sharks – that regularly inhabit rivers – cannot have denticles.
Basic logic!
The fresh water from the source for our drinking water is usually in the 7.5 to 8.5 range (It has approached 8.9 in the summer as algae removes CO2 from the water). In 30+ years of treating it I’ve never seen it “acidic”.
Of course other bodies of fresh water pH values can vary depending on what feeds them, but I doubt if 7.0 and below is the norm.
Does this give these sharks a somewhat ability to fly ?
If this is true, with all these extreme events linked to CO2, mankind may face Sharknadoes !
Sharks evolved in the Ordovician and Silurian eras.
Since then they have survived 400-500 million years during which atmospheric CO2 has ranged from 200 up to 5-10,000 ppm.
But today, an increase of atmospheric CO2 from 280 to 500 ppm is somehow going to dissolve their scales?
Shark scales were just fine at 5000 ppm CO2.
Why would they dissolve at 500 ppm?
Is it too alkaline form them?
Here is a Silurian shark.
Sharks evolved in the Ordovician and Silurian during which atmospheric CO2 ranged approximately from 1000-10,000 ppm.
https://images.app.goo.gl/SQ8pV73eZraynFbh6
On the shark’s skin, the scales did just fine and the oceans were just as alkaline then as now.
In the shark’s brains, the first developments were taking place that would later evolve into human’s ability to fabricate false climate disaster stories as a strategy to gain power in hominid societies.
“Acidified oceans may corrode shark scales”
Or maybe not.
Machael 2
It is telling that the sharks have evolved the ability to replace the denticles, much as they do their teeth. The question is whether the denticle replacement is a fixed period or a response to decrease in swimming efficiency. Also unknown, is if it is currently a fixed period, whether that might be changed by reduced swimming efficiency.
My bs-o-meter has just gone off the scale.
Consider the Bull Shark (a.k.a “Zambezi shark” and “Lake Nicaragua shark”)
“Bull sharks can thrive in both salt and fresh water and can travel far up rivers. They have been known to travel up the Mississippi River as far as Alton, Illinois, about 700 miles from the ocean.” [wiki “Bull Shark”]
“… it was discovered that they were able to jump along the rapids of the San Juan River (which connects Lake Nicaragua and the Caribbean Sea), almost like salmon. As evidence of these movements, bull sharks tagged inside the lake have later been caught in the open ocean (and vice versa), with some taking as little as 7–11 days to complete the journey.” [wiki ‘Lake Nicaragua’]
I wonder what are the pHs of the Mississippi River and Lake Nicaragua?
Bull sharks would likely travel further up the Mississippi if there were no locks and dams. Alton is where the dams begin.
Charles Rotter / ~cr comment: always good for an unexpected / undeserved laugh:
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Marine biology: Acidified oceans may corrode shark scales
Prolonged exposure to high carbon dioxide (acidified) seawater may corrode tooth-like scales (denticles) covering the skin of puffadder shysharks, a study in Scientific Reports suggests. As ocean CO2 concentrations increase due to human activity, oceans are becoming more acidic, with potential implications for marine wildlife. Although the effects of acidified water have been studied in several species, this is the first observed instance of denticle corrosion as a result of long-term exposure.
Lutz Auerswald and colleagues investigated the effects of exposure to acidified seawater in puffadder shysharks. The authors found that in three sharks housed in acidified seawater for nine weeks, 25% of denticles on average were damaged, compared to 9.2% of denticles in a control group of three sharks that had been housed in non-acidic water.
They suggest that such corrosion may impair the sharks’ skin protection and open-water sharks’ ability to swim, as denticle surface affects their swimming speed. They also speculate that similar corrosion may occur in sharks’ teeth (which have the same structure and composition as denticles), which may negatively impact their feeding.
However, the authors also found that although exposure was linked with increased carbon dioxide concentrations in blood taken from a total of 36 sharks housed in acidified seawater for different periods of time, concentrations of carbonate also increased. This prevented the blood from becoming more acidic, suggesting that these sharks may be able to adjust to high CO2 conditions during periods of exposure.
###
Article and author details
Acid-base adjustments and first evidence of denticle corrosion caused by ocean acidification conditions in a demersal shark species
Corresponding author:
Lutz Auerswald
Department of Environment, Forestry and Fisheries and Stellenbosch University, Stellenbosch, South Africa DOI 10.1038/s41598-019-54795-7
Online paper:
https://www.nature.com/articles/s41598-019-54795-7
From EurekAlert!
~cr comment. PH of 7.3 expected in the year 2300, probably under RCP 8.5
Another miracle of self-propagation:
– ocean warms, outgassing CO₂
– CO₂ warming atmosphere: warms the oceans
– external energy supply unneeded for that “tipping points game!”
– poor sharks can’t help, shortened life expectancy AND maroded living quality due to teeth maladies.
____________________________________
What will Mrs. Shark think of Mr. “bad teeth” Shark.