Ocean acidification could degrade sharks’ tough skin
The tough, toothy skin of sharks may be no match for the acidified oceans of the future. After nine weeks of exposure to seawater doctored to mimic projected acidic levels in 2300, corrosion had frayed the edges of many denticles — the toothlike protrusions that make up sharkskin — on three puffadder shysharks, researchers report December 19 in Scientific Reports. Damaged denticles could make sharks more vulnerable to infection or injury and increase the drag on shark’s sleek skin. Oceans gradually acidify as the seawater absorbs increasing amounts carbon dioxide from the atmosphere and converts it into carbonic acid (SN: 6/2/19). Climate change scientists estimate that, if humans continue to burn fossil fuels and emit CO₂ at current levels, the average pH of oceans will dip from 8.1 today to 7.3 by 2300. Ocean acidification can cause a host of problems for marine life: It can weaken the calcium carbonate shells of clams and other bivalves (SN: 8/26/19), make corals more brittle (SN: 2/23/16) and...