Global Warming Could Allow Squid to Thrive

Ellie Teng ‘21

Figure 1. Squid could potentially have a resilience to increased CO2 content.

The unique swimming technique of squid requires energy and oxygen. Jet propulsion allows the cephalopods to rapidly move about, but requires a large output of energy, thereby increasing the demand for oxygen. There is evidence suggesting increased CO2 has adverse effects on squid respiratory performance, however, there has been no research on the effects of prolonged exposure to CO2 for adult cephalopods. In this study, the research team experimented with two tropical cephalopod species: the two-toned pygmy squid, Idiosepius pygmaeus, and the bigfin reef squid, Sepioteuthis lessoniana.

The researchers found both the cephalopods’ aerobic performance and recovery after exhaustive exercise while in the presence of elevated CO2 levels to be unaffected. In cephalopods, the effects of increased CO2 content on respiratory performance seem to be both species specific as well as life stage specific. Very high CO2  content had no effect on oxygen consumption in juvenile common cuttlefish (Sepia officinalis), but similar amounts of CO2 reduced oxygen uptake during the late-stage embryo incubation period. The reduced oxygen uptake is suspected to be a result of  acid–base regulatory mechanisms in cephalopods. Acid–base regulatory ability is a trait in cephalopods that allows them to successfully confront the issue with respiratory CO2 that can result in intracellular and extracellular pH differences.

The ability of these two cephalopod species to cope with prolonged exposure to elevated CO2 without a change in their aerobic abilities suggests some resilience to an increasingly CO2 rich environment. These results indicate that cephalopods are likely to be resilient to increasing CO2 levels in their habitats.



  1. B. Spady, et al., Aerobic performance of two tropical cephalopod species unaltered by prolonged exposure to projected future carbon dioxide levels. Conservation Physiology (2019). Doi: 10.1093/conphys/coz024.
  2. Image retrieved from:



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