Temperature tolerance of different larval stages of the spider crab Hyas araneus exposed to elevated seawater PCO2

Abstract

IntroductionExposure to elevated seawater PCO2 limits the thermal tolerance of crustaceans but the underlying mechanisms have not been comprehensively explored. Larval stages of crustaceans are even more sensitive to environmental hypercapnia and possess narrower thermal windows than adults.ResultsIn a mechanistic approach, we analysed the impact of high seawater CO2 on parameters at different levels of biological organization, from the molecular to the whole animal level. At the whole animal level we measured oxygen consumption, heart rate and activity during acute warming in zoea and megalopa larvae of the spider crab Hyas araneus exposed to different levels of seawater PCO2. Furthermore, the expression of genes responsible for acid–base regulation and mitochondrial energy metabolism, and cellular responses to thermal stress (e.g. the heat shock response) was analysed before and after larvae were heat shocked by rapidly raising the seawater temperature from 10°C rearing temperature to 20°C. Zoea larvae showed a high heat tolerance, which decreased at elevated seawater PCO2, while the already low heat tolerance of megalopa larvae was not limited further by hypercapnic exposure. There was a combined effect of elevated seawater CO2 and heat shock in zoea larvae causing elevated transcript levels of heat shock proteins. In all three larval stages, hypercapnic exposure elicited an up-regulation of genes involved in oxidative phosphorylation, which was, however, not accompanied by increased energetic demands.ConclusionThe combined effect of seawater CO2 and heat shock on the gene expression of heat shock proteins reflects the downward shift in thermal limits seen on the whole animal level and indicates an associated capacity to elicit passive thermal tolerance. The up-regulation of genes involved in oxidative phosphorylation might compensate for enzyme activities being lowered through bicarbonate inhibition and maintain larval standard metabolic rates at high seawater CO2 levels. The present study underlines the necessity to align transcriptomic data with physiological responses when addressing mechanisms affected by an interaction of elevated seawater PCO2 and temperature extremes.Electronic supplementary materialThe online version of this article (doi:10.1186/s12983-014-0087-4) contains supplementary material, which is available to authorized users.

Impact of ocean acidification on thermal tolerance and acid–base regulation of Mytilus edulis from the White Sea

“…Our findings on oxygen and acid-base status of haemolymph provide evidence that the T P is also shifted downwards by CO 2 as reported for other marine ectotherms (e.g. Metzger et al 2007;Walther et al 2009;Dissanayake and Ishimatsu 2011;Schalkhausser et al 2012;Schiffer et al 2014; for review see Pörtner 2012). Haemolymph PO 2 was initially slightly increased under hypercapnia but decreased progressively above 19 °C a pattern that only occurred above 22 °C under normocapnia.…”

An atlas of larval organogenesis in the European shore crab Carcinus maenas L. (Decapoda, Brachyura, Portunidae)

“…Laboratory and field studies on the development of brachyuran larvae have fostered our understanding of diverse ecophysiological aspects such as phenotypic plasticity in developmental traits, heterochrony in developmental patterns, carry-over effects on life-history traits, and adaptive mechanisms that enhance tolerance to fluctuations in environmental abiotic and biotic factors. Furthermore, a diverse range of biological topics has been analysed using brachyuran larvae as models including aspects of the physiology of aquatic-terrestrial and marine-limnic transitions, dispersal potential of invasive species, adaptive significance of abbreviated development, and effects of acclimation (reviews [ 4 , 7 ]) but also the effects of environmental change-induced abiotic stress on ontogenetic stages of marine organisms [ 14 ].…”

The sea urchin Lytechinus variegatus lives close to the upper thermal limit for early development in a tropical lagoon

“…2013; Schiffer et al. 2014). In at least one species of crab, the late larval stages show less tolerance to thermal stress than do early larval stages (Storch et al.…”

“…The few published studies demonstrate that different life stages often have different thermal tolerances, but do not provide support for a consistent pattern. Studies of crustaceans have found that larval stages have lower thermal tolerance than adults (e.g., Miller et al 2013;Schiffer et al 2014). In at least one species of crab, the late larval stages show less tolerance to thermal stress than do early larval stages (Storch et al 2011).…”