Cuttlefish take a strong place in our imagination. They are the original sea monsters immortalized in Jules Verne's classic novel Twenty Thousand Leagues Under the Sea and in Scandinavian folklore, where a cephalopod creature emerges from the sea to wreak havoc as octopus.
New Science shows that nobody should write them off in the real world. They will probably be much longer than humans, even if the planet is exposed to strong climatic changes.
Some marine biologists have assumed that the squid population would be hit in waters with higher carbon dioxide concentrations. And that makes sense: squid blood is very sensitive to changes in acidity, and scientists say the animals are already at the edge of their oxygen levels because their swimming technique is so energy-intensive.
An ocean of climate problems
Atmospheric concentrations of carbon dioxide are bound to increase. Before the Industrial Revolution, 280 ppm (parts per million) was measured. Today, this figure has risen to 400ppm and is expected to rise to over 900ppm by the end of the century unless emissions are reduced. Rapid change is expected to have a profound impact on ocean ecosystems.
Carbon dioxide dissolved in the water forms carbonic acid. This increased acidity could lead to a chain reaction that is detrimental to most animals. In 2017, Chinese scientists found that it has a negative effect on tiny cyanobacteria. These tiny creatures play a crucial role in the oceans' ecosystems as they perform a process called nitrogen fixation and convert nitrogen into ammonia and other molecules that many organisms need.
The hope is that new regulations will prevent the carbon dioxide concentration from ever reaching 900 ppm. The James Cook researchers were curious how this value could affect cuttlefish.
Cuttlefish sets new standards
They chose two types of tropical cuttlefish: the bicolor dwarf and the bigfin reef squid – and caught them with mesh nets. Back in their laboratory, the researchers have divided them into different tanks with different carbon dioxide concentrations.
CO2 levels of the century, "said lead researcher Blake Spady in a statement.
The scientists speculated that the results were not only unaffected, but even suggested that the octopus would perform well in the altered ecosystem. If their typical predators and their prey are adversely affected, this would help the squid find food.
"We believe that certain species are well suited to succeed in our fast-changing oceans, and these squid species could be among them," Spady added. "It is very certain that it will be a completely different world."