Research press release


Scientific Reports

Marine biology: Acidified oceans may corrode shark scales


今回、Lutz Auerswaldたちの研究グループは、モヨウウチキトラザメを使って、酸性化した海水への曝露の影響を調査した。酸性化した海水中で9週間飼育した3匹において、小歯状突起の平均25%が損傷していた。非酸性の水で飼育した3匹のサメ(対照群)では小歯状突起の9.2%が損傷していた。Auerswaldたちは、小歯状突起の表面がサメの遊泳速度に影響するため、小歯状突起の侵食は、サメの皮膚の保護と外洋に生息するサメの遊泳能力を損なう可能性があるという考えを示している。さらにAuerswaldたちは、(構造と組成が小歯状突起と同じ)サメの歯にも同様の侵食が起こり、摂食に悪影響を与えるかもしれないと推測している。


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 CO2 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.

doi: 10.1038/s41598-019-54795-7


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