Climate change is one of the greatest threats to biodiversity and ecosystems across the planet. Research into climate change typically highlights the effects on whole habitats and ecosystems. However, new research on octopuses details how a change to the environment can impact a single species, affect their growth and potentially damage their chances of survival.
It is well documented that almost every ecosystem worldwide is threatened by climate change; in particular due to warming temperatures [1]. These hotter climates can cause various problems, from prolonged droughts in grasslands [2] to melting sea ice in the Arctic. Earth’s oceans take up over 70% of space on the planet, acting as the largest heat sink, already having absorbed 80% of the heat produced by climate change. As a result, marine ecosystems are under major threat. Whilst a lot of research has been done into the large-scale impacts of climate change on the ocean, only recently have scientists begun to look at the smaller-scale impacts on species or individual organisms. For example, male sea turtles may become increasingly rare due to the hatchlings’ sex being dependent on the temperature of the egg, with females being produced at higher temperatures; the subsequent effects of this on the population’s genetic health could be dire [3].
Octopus larva (Photo: Matt Wilson)
To further research into how climate change may affect key development processes in individual organisms, scientists from Australia experimentally exposed octopus embryos to future projected ocean temperatures and compared their success to embryos growing in current ocean conditions. The team used Southern keeled octopus (Octopus berrima) embryos, native to Australia, and exposed them to 3 different temperature conditions. The first was a lower average summer temperature of 19℃, the second, a higher average summer temperature of 22℃, and finally, the projected average summer temperature of 26℃ by the end of the century, produced by the IPCC (Intergovernmental Panel on Climate Change). The scientists then compared how the octopus hatchlings developed at these different temperatures.
Hatching success was over 60% lower at 26℃ than it was at 19℃, offering a worrying sign for the future if climate change continues. Hatchlings born in the present conditions weighed twice as much as the embryos kept in the warmer future conditions. Finally, eye development was significantly lower at projected future temperatures than in the current, cooler waters. Since vision plays a key role in cephalopod ecology and behaviour [3], these impacts of warming waters may significantly damage juvenile octopuses’ ability to hunt prey and to evade predators. If hatching success rates are reduced by climate change, the Southern-keeled octopus population may begin to shrink. This research may suggest that other cephalopods could be impacted by climate-driven warming. With octopuses, squid and cuttlefish playing important roles in food chains and ecosystems, global warming could cause significant problems for marine ecosystems [4].
How to Find Another Way
No one wants to imagine baby octopuses – already with the odds stacked against them – having more physiological challenges to face. This study and others like it, offer an important understanding of how species may perform under predicted future global warming. To help this issue, it all goes back to reducing your carbon footprint, which will, in turn, help slow global warming, not only helping tiny baby octopi but so many other species as well.
Article by Fin Mills
Header photo: Tara Silber
References:
Case study: Hua QQ, Kültz D, Wiltshire K, Doubleday ZA, Gillanders BM. Projected ocean temperatures impair key proteins used in vision of octopus hatchlings. Global Change Biology. 2024 Apr;30(4):e17255.
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[5] Borges FO, Sampaio E, Santos CP, Rosa R. Climate-change impacts on Cephalopods: A meta-analysis. Integrative and Comparative Biology. 2023 Dec;63(6):1240-65.
