Juvenile Eastern Oysters More Resilient to Extreme Ocean Acidification than Their Mud Crab Predators

Abstract

Ocean acidification is predicted to impair marine calcifiers' abilities to produce shells and skeletons. We conducted laboratory experiments investigating the impacts of CO2‐induced ocean acidification (pCO2 = 478–519, 734–835, 8,980–9,567; Ωcalcite = 7.3–5.7, 5.6–4.3, 0.6–0.7) on calcification rates of two estuarine calcifiers involved in a classic predator‐prey model system: adult Panopeus herbstii (Atlantic mud crab) and juvenile Crassostrea virginica (eastern oyster). Both oyster and crab calcification rates significantly decreased at the highest pCO2 level. Notably, however, oysters maintained positive net calcification rates in the highest pCO2 treatment that was undersaturated with respect to calcite, while mud crabs exhibited net dissolution (i.e., net loss of shell mass) in calcite‐undersaturated conditions. Secondary electron imaging of oyster shells revealed minor microstructural alterations in the moderate‐pCO2 treatment, and major microstructural and macrostructural changes (including shell dissolution, delamination of periostracum) in the high‐pCO2 treatment. These results underscore the threat that ocean acidification poses for marine organisms that produce calcium carbonate shells, illustrate the strong biological control that some marine calcifiers exert over their shell‐building process, and shows that ocean acidification differentially impacts the crab and oyster species involved in this classical predator‐prey model system.

The Effect of Ocean Acidification on Skeletal Structures

“…Their experiment also shows that freshwater acidification impairs the feeding rates of crayfish, which likely contributes to their negative calcification response to freshwater acidification by reducing the amount of energy available for their molt-mediated process of shell formation. Notably, similar trends have been observed for marine species of decapod crustacea, including for mud crabs whose rates of feeding [15] and calcification [16] were both impaired under acidified conditions.…”

Influence of seagrass on juvenile Pacific oyster growth in two US west coast estuaries with different environmental gradients

“…The full carbonate chemistry system was calculated with CO2SYS (Lewis & Wallace 1998, Orr et al 2018) using CO 2 system constants from Millero (2010), K HSO4 constants of Dickson (1990), and K HF constants of Perez & Fraga (1987). In this study, we focused on the carbonate saturation state of calcite (Ωcalcite) rather than aragonite because, al though less soluble than aragonite, it is thought to be the primary material utilized for shell building in post-settlement juvenile oysters (Gazeau et al 2007, Ries 2011, Dodd et al 2021. Estimated standard sampling errors for metrics of interest were calculated based on a subset of Niskin sampling when 3 crimp-sealed bottle samples from each of 8 Niskins were collected and processed.…”