Transcriptomic response of the Antarctic pteropod Limacina helicina antarctica to ocean acidification

• Published in: BMC Genomics
• Main Authors: Kevin M. Johnson, Gretchen E. Hofmann
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2017
• Subjects: Limacina helicina antarctica; Pteropod; Ocean acidification; Ross Sea; pH; Southern Ocean; Biotechnology; TP248.13-248.65; Genetics; QH426-470; Antarctic; The Antarctic; Antarc*; Antarctica; Limacina helicina
• Online Access: https://doi.org/10.1186/s12864-017-4161-0; https://doaj.org/article/0368f6ee18204a929b97d33dd1950de5

Abstract Background Ocean acidification (OA), a change in ocean chemistry due to the absorption of atmospheric CO2 into surface oceans, challenges biogenic calcification in many marine organisms. Ocean acidification is expected to rapidly progress in polar seas, with regions of the Southern Ocean expected to experience severe OA within decades. Biologically, the consequences of OA challenge calcification processes and impose an energetic cost. Results In order to better characterize the response of a polar calcifier to conditions of OA, we assessed differential gene expression in the Antarctic pteropod, Limacina helicina antarctica. Experimental levels of pCO2 were chosen to create both contemporary pH conditions, and to mimic future pH expected in OA scenarios. Significant changes in the transcriptome were observed when juvenile L. h. antarctica were acclimated for 21 days to low-pH (7.71), mid-pH (7.9) or high-pH (8.13) conditions. Differential gene expression analysis of individuals maintained in the low-pH treatment identified down-regulation of genes involved in cytoskeletal structure, lipid transport, and metabolism. High pH exposure led to increased expression and enrichment for genes involved in shell formation, calcium ion binding, and DNA binding. Significant differential gene expression was observed in four major cellular and physiological processes: shell formation, the cellular stress response, metabolism, and neural function. Across these functional groups, exposure to conditions that mimic ocean acidification led to rapid suppression of gene expression. Conclusions Results of this study demonstrated that the transcriptome of the juvenile pteropod, L. h. antarctica, was dynamic and changed in response to different levels of pCO2. In a global change context, exposure of L. h. antarctica to the low pH, high pCO2 OA conditions resulted in a suppression of transcripts for genes involved in key physiological processes: calcification, metabolism, and the cellular stress response. The transcriptomic ...