Aerobic performance of two tropical cephalopod species unaltered by prolonged exposure to projected future carbon dioxide levels

Abstract

Long-term exposure to projected future CO 2 levels has no effect on the aerobic performance of two tropical cephalopod species. The resting oxygen uptake rates, maximal oxygen uptake rates, aerobic scope, and recovery time of both bigfin reef squid and two-toned pygmy squid were unaltered by elevated CO 2 .

Metabolic proxy for cephalopods: Stable carbon isotope values recorded in different biogenic carbonates

“…Commonly, the metabolic rate of marine ectotherms is determined by directly measuring oxygen consumption through respirometry in laboratory experiments (Burford et al, 2019;Grigoriou & Richardson, 2009;Seibel et al, 1997;Spady et al, 2019).…”

“…Commonly, the metabolic rate of marine ectotherms is determined by directly measuring oxygen consumption through respirometry in laboratory experiments (Burford et al., 2019; Grigoriou & Richardson, 2009; Seibel et al., 1997; Spady et al., 2019). However, this method cannot be applied in the field to determine their metabolic performance (Treberg et al., 2016).…”

Antagonistic Interactions and Clutch-Dependent Sensitivity Induce Variable Responses to Ocean Acidification and Warming in Squid (Doryteuthis pealeii) Embryos and Paralarvae

“…Metabolic suppression was long suggested as an expected impact of OA on squid because squid hemocyanins are very sensitive to pH, squid operate at the very peak of blood oxygen utilization, and the resultant Bohr shift would starve the animal of oxygen (Pörtner, 1990(Pörtner, , 1994Fabry et al, 2008;Seibel, 2016). While metabolic suppression was observed in jumbo squid, Dosidicus gigas, exposed to 1000 ppm CO 2 , more recent studies have demonstrated no metabolic impacts to adults of bigfin reef squid, Sepioteuthis lessoniana, and pygmy reef squid, Idiosepius pygmaeus, as well as adults and juvenile D. gigas, and D. pealeii at equal or greater levels of acidification (Rosa and Seibel, 2008;Hu et al, 2014;Birk et al, 2018;Spady et al, 2019). It is possible that metabolic sensitivity to acidification is life stage dependent in cephalopods with juveniles and adults having the robust physiological machinery needed to manage under OA stress, while the gears of development may be slowed in embryos.…”

“…Variability of pH in natural systems is thought to decrease impacts in some organisms by reducing exposure time, which appears to be an important factor in acidification's impact on D. pealeii eggs (Shaw et al, 2013). While a growing body of literature is beginning to suggest squid, at least embryos and adults (there is still a great deal left to understand with respect to paralarvae), may be fairly robust in the face of OA, these responses may be taxon, population, or region specific making it difficult to generalize (Kroeker et al, 2017;Birk et al, 2018;Spady et al, 2019). Warming, however, clearly has its limits in D. pealeii embryonic development, but squid have the advantage of mobility in coping with that (Doubleday et al, 2016).…”

Adaptándose a un medio cambiante:

“…Para evaluar la plasticidad conductual de los calamares ante estas alteraciones, científicos de la Universidad de James Cook (Spady et al, 2019) expusieron al calamar pigmeo bicolor (Idiosepius pygmaeus) y al calamar de arrecifes (Sepiotheutis lessoniana), dos especies que ocupan nichos completamente diferentes, a las posibles futuras condiciones de CO 2 . Sus experimentos los llevaron a obtener resultados completamente inesperados: la acidificación del océano no es ni será un obstáculo para los procesos fisiológicos de los calamares, ya que demostraron que, aún exponiéndose a condiciones extremadamente altas de CO 2, sus habilidades respiratorias permanecen completamente estables.…”