CO2-driven ocean acidification weakens mussel shell defense capacity and induces global molecular compensatory responses. (March 2020)

• Record Type: Journal Article
• Authors: Zhao, Xinguo; Han, Yu; Chen, Bijuan; Xia, Bin; Qu, Keming; Liu, Guangxu
• Is Part Of: Chemosphere. Volume 243(2020)
• Publication Date: 2020-03
• Subjects: Ocean acidification -- Mussel -- Calcification -- Acid-base status -- Defense capacity -- Mantle transcriptome sequencing; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2019.125415
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: Oceanic uptake of atmospheric CO2 is reducing seawater pH and shifting carbonate chemistry within, a process termed as ocean acidification (OA). Marine mussels are a family of ecologically and economically significant bivalves that are widely distributed along coastal areas worldwide. Studies have demonstrated that OA greatly disrupts mussels' physiological functions. However, the underlying molecular responses (e.g., whether there were any molecular compensation mechanisms) and the extent to which OA affects mussel shell defense capacity remain largely unknown. In this study, the thick shell mussels Mytilus coruscus were exposed to the ambient pH (8.1) or one of two lowered pH levels (7.8 and 7.4) for 40 days. The results suggest that future OA will damage shell structure and weaken shell strength and shell closure strength, ultimately reducing mussel shell defense capacity. In addition, future OA will also disrupt haemolymph pH and Ca 2+ homeostasis, leading to extracellular acidosis and Ca 2+ deficiency. Mantle transcriptome analyses indicate that mussels will adopt a series of molecular compensatory responses to mitigate these adverse effects; nevertheless, weakened shell defense capacity will increase mussels' susceptibility to predators, parasites and pathogens, and thereby reduce their fitness. Overall, the findings of this study have significant ecological and economic implications, and will enhance our understanding of the future of the mussel aquaculture industry and coastal ecosystems. Graphical abstract: Image 1 Highlights: OA will damage shell structure, and reduce shell strength and shell closure strength. OA will lead to extracellular acidosis and Ca 2+ deficiency. OA will significantly alter gene expression profile in mantle tissue. OA will weaken mussels' shell defense capacity, and thus reduce their fitness. The findings of this study have significant ecological and economic implications.