Influence of CO2-induced acidification on the reproduction of a key Arctic copepod Calanus glacialis

Medium-term exposure of the North Atlantic copepod <i>Calanus finmarchicus</i> (Gunnerus, 1770) to CO<sub>2</sub>-acidified seawater: effects on survival and development

“…Incubation in seawater acidified with ∼ 1000 ppm CO 2 had no significant effect on the hatching success of eggs from wild-caught females of either C. helgolandicus (Mayor et al, 2012) or C. glacialis (Weydmann et al, 2012). The results from the present medium-term study on cohorts of C. finmarchicus eggs revealed no apparent effect on survival after 28 days of exposure to seawater acidified with 3300 ppm CO 2 .…”

“…Exposure to high levels of CO 2 -induced acidification has previously been shown to reduce hatching success. The hatching success of C. finmarchicus (Mayor et al, 2007) and C. glacialis (Weydmann et al, 2012) eggs was severely reduced by incubation in seawater acidified with ∼ 8000 and ∼ 7000 ppm CO 2 , respectively. Within this range of CO 2 levels the present study also revealed a strong and significant reduction of the survival in the raised cohorts; survival was reduced by ∼ 50 % in the treatment with 7300 ppm, while no animals developed at 9700 ppm CO 2 (except two individuals which survived arrested as nauplii in one of the three replicates).…”

“…In a similar experiment, where more moderate CO 2 levels were applied, no significant effect on hatching success was observed when eggs from wildcaught Calanus helgolandicus (Claus, 1863) females were incubated in seawater with 1000 ppm CO 2 (e.g., a level that may be reached within the end of the century) (Mayor et al, 2012). Recently, Weydmann et al (2012) reported that egg production in wild-caught Calanus glacialis (Jaschnov, 1955) females were unaffected by a pH level of 7.6 and 6.9 (corresponding to a pCO 2 of ∼ 1000 and ∼ 7000 ppm at the in situ temperature used, respectively), but a reduced hatching success was observed among the eggs that were incubated at pH 6.9. In wild-caught Calanus sinicus (Brodsky, 1962), no effect on adult survival and egg production rate was observed below 10 000 ppm CO 2 during an eight day long incubation period (Zhang et al, 2011).…”

Sensitivity to ocean acidification parallels natural pCO 2 gradients experienced by Arctic copepods under winter sea ice

“…Copepods have a mainly chitinous exoskeleton, so they are not as vulnerable to calcium carbonate undersaturation as other calcifying Arctic organisms, such as pteropods (10). However, evidence for impacts of elevated CO 2 have been demonstrated for a number of temperate copepod species and life history stages (11)(12)(13) [although only one study (11) showed responses occurring at levels projected for the year 2100], whereas others, including temperate calanoids, appear more resilient (14,15). OA impacts are most likely to occur as a result of increased energetic costs of maintaining homeostasis of physiological processes [e.g., acidbase balance (16)] under elevated CO 2 conditions, with resultant shifts in growth, fecundity, and survival, yet these responses remain relatively understudied for this ecologically important group.…”

Effects of acute ocean acidification on spatially-diverse polar pelagic foodwebs: Insights from on-deck microcosms

“…In terms of direct physiological responses, most studies have found no direct effects on copepods at CO 2 levels within the range expected by the end of this century (Kurihara et al 2004;Watanabe et al 2006, Kurihara and Ishimatsu 2008, Zhang et al 2011, Vehmaa et al 2012, Weydmann et al, 2012, McConville et al 2013, Niehoff et al 2013. It is to be noted that the majority of these studies focussed on adult females whereas only a few have concentrated on other life-history stages which are likely to show greater sensitivity to elevated pCO 2 (Kurihara et al 2004, Fitzer et al 2012, Lewis et al 2013, Cripps et al 2014).…”