Ocean acidification, warming and feeding impacts on biomineralization pathways and shell material properties of Magallana gigas and Mytilus spp.

Citation

Mele I, McGill RA, Thompson J, Fennell J & Fitzer S (2023) Ocean acidification, warming and feeding impacts on biomineralization pathways and shell material properties of Magallana gigas and Mytilus spp.. Marine Environmental Research, 186, Art. No.: 105925. https://doi.org/10.1016/j.marenvres.2023.105925

Abstract
Molluscs are among the organisms affected by ocean acidification (OA), relying on carbon for shell biomineralization. Metabolic and environmental sourcing are two pathways potentially affected by OA, but the circumstances and patterns by which they are altered are poorly understood. From previous studies, mollusc shells grown under OA appear smaller in size, brittle and thinner, suggesting an important alteration in carbon sequestration. However, supplementary feeding experiments have shown promising results in offsetting the negative consequences of OA on shell growth. Our study compared carbon uptake by δ13C tracing and deposition into mantle tissue and shell layers in Magallana gigas and Mytilus species, two economically valuable and common species. After subjecting the species to 7.7 pH, +2 °C seawater, and enhanced feeding, both species maintain shell growth and metabolic pathways under OA without benefitting from extra feeding, thus, showing effective acclimation to rapid and short-term environmental change. Mytilus spp. increases metabolic carbon into the calcite and environmental sourcing of carbon into the shell aragonite in low pH and high temperature conditions. Low pH affects M. gigas mantle nitrogen isotopes maintaining growth. Calcite biomineralization pathway differs between the two species and suggests species-specific response to OA.

Keywords
Pollution; Aquatic Science; General Medicine; Oceanography

Journal
Marine Environmental Research: Volume 186