Ocean acidification and temperature rise: effects on calcification during early development of the cuttlefish Sepia officinalis

Abstract

Abstract:This study investigated the effects of seawater pH (i.e. 8.10, 7.85 and 7.60) and temperature (16 and 19°C) on (i) the abiotic conditions in the fluid surrounding the embryo (viz. the perivitelline fluid),(ii) growth, development and (iii) cuttlebone calcification of embryonic and juvenile stages of the cephalopod Sepia officinalis. Egg swelling increased in response to acidification or warming, leading to an increase in egg surface while the interactive effects suggested a limited plasticity of the swelling modulation. Embryos experienced elevated pCO 2 conditions in the perivitelline fluid (> 3-fold higher pCO 2 than that of ambient seawater), rendering the medium under-saturated even under ambient conditions. The growth of both embryos and juveniles was unaffected by pH, whereas 45 Ca incorporation in cuttlebone increased significantly with decreasing pH at both temperatures. This phenomenon of hypercalcification is limited to only a number of animals but does not guarantee functional performance and calls for better mechanistic understanding of calcification processes.

Environmental pH, O2 and Capsular Effects on the Geochemical Composition of Statoliths of Embryonic Squid Doryteuthis opalescens

“…Aragonite is a solid, acellular, metabolically inert, crystalline structure [76] that is ~95% CaCO 3 [35] and differs from other calcified structures found in cephalopods that are porous, cellular and metabolically active, such as cuttlebone, which have been shown to become less porous (hypercalcification or increased CaCO 3 density) in response to hypercapnia [47,77]. Further, if hypercalcification or hypocalcification is induced by a treatment, we would expect all element:calcium ratios to be significantly increased (hypocalcification) or decreased (hypercalcification).…”

“…The structures of the capsule can connect the external chemical environment to the embryo via the capsular membranes, interstitial jelly and the chorion membrane (hereafter, these effects are collectively referred to as "capsular effects"). The pH/pCO 2 and [O 2 ] of the perivitelline fluid that surrounds the embryo are impacted additively by the environment and by the physiological processes of the embryo itself [17][18][19][42][43][44][45][46][47]. Elemental incorporation within statoliths can be influenced by the environment [30,33,34,48], but physiological process impacts on statolith geochemistry, including processes within the statocyst [41], embryo [18,19,45,46], as well as within outer-embryo structures [49,50], are not well understood.…”

“…The cephalopod-embryo metabolic rate greatly increases at the end of development [42,45,46] and is variable among embryos within the capsule [53]. The molluscan metabolic rate is highly influenced by temperature [45,46,54] and environmental oxygen [20,55,56]; cephalopods can be influenced by environmental pH/pCO 2 levels at the embryonic stages [45][46][47]52], but are tolerant at older stages [57,58]. As the statolith grows, the volume of the statolith increases exponentially.…”

Temperature and acidification variability reduce physiological performance in the intertidal zone porcelain crab Petrolisthes cinctipes

“…survival, via the CSR). Reduced constant pH alone has been shown to reduce the metabolism of embryonic and larval porcelain crabs Ceballos-Osuna et al, 2013) and larval urchins (Dorey et al, 2012), resulting in reduced scope for growth. Yet there are complexities in metabolic responses whereby not all individuals reduce metabolism to the same degree, if at all Ceballos-Osuna et al, 2013), suggesting the potential for adaptive responses to ocean acidification exists.…”

Biochemical adaptation to ocean acidification

“…Taxon-specific analysis reveals the most heavily calcifying groups (calcified algae, corals, mollusks and the larval stages of echinoderms) are most negatively affected by decreases in pH (Kroeker et al, 2013). It is likely that there are environmental pH threshold limits to plastic responses, beyond which acclimation does not occur and fitness is impaired (Dorey et al, 2013).…”