Assessment of ocean acidification and warming on the growth, calcification, and biophotonics of a California grass shrimp

Abstract

Cryptic colouration in crustaceans, important for both camouflage and visual communication, is achieved through physiological and morphological mechanisms that are sensitive to changes in environmental conditions. Consequently, ocean warming and ocean acidification can affect crustaceans’ biophotonic appearance and exoskeleton composition in ways that might disrupt colouration and transparency. In the present study, we measured growth, mineralization, transparency, and spectral reflectance (colouration) of the caridean grass shrimp Hippolyte californiensis in response to pH and temperature stressors. Shrimp were exposed to ambient pH and temperature (pH 8.0, 17 °C), decreased pH (pH 7.5, 17 °C), and decreased pH/increased temperature (pH 7.5, 19 °C) conditions for 7 weeks. There were no differences in either Mg or Ca content in the exoskeleton across treatments nor in the transparency and spectral reflectance. There was a small but significant increase in percent growth in the carapace length of shrimp exposed to decreased pH/increased temperature. Overall, these findings suggest that growth, calcification, and colour of H. californiensis are unaffected by decreases of 0.5 pH units. This tolerance might stem from adaptation to the highly variable pH environment that these grass shrimp inhabit, highlighting the multifarious responses to ocean acidification, within the Crustacea.

Vulnerability of juvenile hermit crabs to reduced seawater pH and shading

“…other species may have their exoskeletal mineral composition unaffected (Lowder et al, 2017), as observed for P. criniticornis in the current study, even under the combined stressors treatment. The ability to maintain, or even increase calcification rates and/or compensate dissolution rates when exposed to seawater acidification is well known amongst crustaceans (McDonald et al, 2009;Ries et al, 2009;Wickins, 1984), mollusks and echinoderms (Findlay et al 2011;Wood et al, 2008).…”

Tolerant Larvae and Sensitive Juveniles: Integrating Metabolomics and Whole-Organism Responses to Define Life-Stage Specific Sensitivity to Ocean Acidification in the American Lobster

“…Among marine invertebrates, crustaceans, and especially decapods, are considered to be among the least affected calcifying species by the exposure to low pH/high p CO 2 conditions [ 8 , 12 ] in terms of survival, growth, metabolism, acid-base balance, carapace mineralisation, and behaviour [ 21 , 22 , 23 , 24 , 25 , 26 ]. While different species can show opposite responses [ 27 , 28 ], this overall low sensitivity to OA may be linked to crustaceans homeostatic and regulatory abilities, their capacity to relocate exoskeletal calcium (Ca 2+ ) and carbonate (CO 3 2− ) ions during moulting, and their impermeable cuticle protecting the carapace from dissolution and limiting exchanges with the surrounding environment [ 28 , 29 , 30 ].…”

Impacts of pH on the Fitness and Immune System of Pacific White Shrimp

“…Mantis shrimps did not show any changes in their survival or growth following exposure to reduced pH of 7.57 for 6 months (DeVries et al, 2016). Lowder et al (2017) reported that California grass shrimps exposed to a pH of 7.48 survived 7 weeks without any significant difference in carapace length compared to the controller group (pH of 7.98). Other studies documented negative impacts at similar low pH levels.…”