“Ocean acidification and warming concerns, however, are vastly overstated and generally far out of touch with reality. In almost every instance, the predicted degree of harm is exaggerated due to improper scenario inputs that utilize the most extreme scenarios of future temperature and seawater pH. Furthermore, their projections fail to take into account the ability of species to acclimate and adapt, both within and across generations.”
Shark Week has become a staple of American television. Debuting in the summer of 1988 the event has morphed into a week-long block of programming at the Discovery Channel featuring all kinds of entertaining and educational shows focusing on sharks.
Hot off the heels of this year’s event, I could not help but be drawn to the title of an article pertaining to these menacing but often misunderstood fish species: “Shark teeth can resist ocean acidification.”
Written by Leung et al. (2022) and published in the journal Global Change Biology, the article examined how the supposed twin-evils of the radical environmental movement, i.e., global warming and ocean acidification, might impact sharks, and in particular, their teeth.
To insert a little background here, for decades now climate alarmists have prostituted model-based projections into claiming that global warming and ocean acidification are inflicting serious harm and damage across Earth’s flora and fauna. And if such damage is not stopped, they say it will ultimately lead to the extinction of numerous species.
Ocean acidification and warming, however, are vastly overstated and generally far out of touch with reality. In almost every instance, the predicted degree of harm is exaggerated due to improper scenario inputs that utilize the most extreme scenarios of future temperature and seawater pH. Furthermore, their projections fail to take into account the ability of species to acclimate and adapt, both within and across generations.
When these and other constraints are properly accounted for, predictions of future doom and gloom give way to scenarios of hope with scientists recognizing global warming and ocean acidification to be largely non-problems.
The paper by Leung et al. falls into this latter category, despite the fact that they utilized one of the more extreme scenarios of future global warming and ocean acidification. Focusing on the Port Jackson shark (Heterodontus portusjacksoni) the team of six researchers reared newly-hatched juvenile sharks for two months under two temperature (ambient or ambient +3°C) and two ocean acidification (ambient seawater pH or ambient -0.3 pH units) regimes under controlled laboratory conditions.
At the end of the experimental period the authors examined mechanical and mineralogical properties of the sharks’ teeth in an effort to discern any differences among treatments. The importance of their work are its implications for predator-prey interactions and energy dynamics in future marine environments, where ocean acidification and warming are predicted to compromise them.
Results of the study revealed slight differences in various mechanical properties under ocean acidification alone or temperature alone. Higher temperature, for example, decreased both teeth elasticity (indicated by a higher elastic modulus) and mechanical resilience, whereas ocean acidification increased teeth elasticity and reduced teeth hardness (see Figure 1).
Figure 1. The mechanical properties of shark teeth, including (a) hardness, (b) elastic modulus and (c) mechanical resilience after exposure to different seawater temperature and pH treatment conditions (mean + SE, n = 4). Control = 16°C, pH 8.0; OA = 16°C, pH 7.7; Temp = 19°C, pH 8.0; OA × Temp = 19°C, pH 7.7. Source: Leung et al. (2022).
However, when in combination, Leung et al. found that this “benthic shark was able to adjust mineralogical properties of its teeth to maintain their durability under future seawater conditions (i.e. increased acidity and temperature), suggesting a potential acclimatization capacity to tolerate climate change stressors.”
In other words, the researchers observed that the durability of the sharks’ teeth increased; they were “less prone to physical damage due to the production of more elastic teeth.” Consequently, Leung et al. conclude their findings “offer a more optimistic sense about [the shark species’] fitness and survival in the future.”
So it is that another scientific study has shown ocean acidification and warming to be a non-problem. And that is good news for the producers of future Shark Week television events—they will continue to get all the footage they could ever want of those enormous pearly-whites chomping away in another good old-fashioned shark-feeding frenzy!
Leung, J.Y.S., Nagelkerken, I., Pistevos, J.C.A., Xie, Z., Zhang, S. and Connell, S.D. 2022. Shark teeth can resist ocean acidification. Global Change Biology 28: 2286-2295, DOI: 10.1111/gcb.16052.