A transcriptomic analysis of the response of the arctic pteropod Limacina helicina to carbon dioxide-driven seawater acidification

Abstract

Ocean acidification from the uptake of anthropogenic carbon dioxide (CO 2 ) is regarded as a critical threat particularly to marine calcifying organisms. The arctic pteropod Limacina helicina may be one of the first polar organisms that are expected to display early sensitivity to ocean acidification, but a molecular approach as a foundation for understanding the effect of ocean acidification on this pteropod has rarely been reported. In this study, we examined the sublethal effects of CO 2 -driven seawater acidification at the transcriptome level in L. helicina. cDNAs, treated under control (pH 8.2), high-CO 2 (pH 7.5), and extreme-CO 2 (pH 6.5) conditions, generated a total of 31,999,474 reads, comprising a total of 2,271,962,654 bp, using the Illumina platform. De novo assembly yielded 53,121 transcripts comprising 31.79 Mbp. Among the upregulated genes, 346 (0.7 %) and 655 (1.2 %) genes responded to extreme-level CO 2 (pH 6.5) and high-level CO 2 (pH 7.5), respectively. Also, 76 (0.1 %) transcripts were commonly upregulated in both conditions. Among the downregulated genes, 690 (1.3 %) and 739 (1.4 %) genes were in response to extreme-level CO 2 and high-level CO 2 , respectively. Also, 270 downregulated genes (0.5 %) were affected in both acidic stress conditions. Moreover, 504 transcripts (1 %) of biomineralization-related genes were identified; 16 of these genes showed differential expression in response to acidified seawater. The dataset provides the first comprehensive overview of changes in transcript levels in the arctic pteropod L. helicina in response to increased CO 2 , emphasizing the potential impact of future environmental change and ocean acidification on Arctic species with external calcified structures.

El Niño-Related Thermal Stress Coupled With Upwelling-Related Ocean Acidification Negatively Impacts Cellular to Population-Level Responses in Pteropods Along the California Current System With Implications for Increased Bioenergetic Costs

“…At the cellular and physiological level, however, we observed a remarkable shift from temperature to low pH and low ar -driven responses. The upwelling-induced low ar /pH conditions elicit similarly high levels of cellular stress and damage, as preliminarily demonstrated by Koh et al (2015), and can resonate on physiological levels. At the cellular level, the action mode of low ar and pH elicits an excess in ROS production.…”

“…LPX might have double negative implications for organisms: First, PUFA sensitivity to LPX results in their decrease (Yin and Pörter, 2003), leaving organisms without the essential lipid structure and reserves. Second, LPX increases ROS-induced structural damage of cell membranes (Bou et al, 2008), as demonstrated by the activation of genes involved in membrane processes (Koh et al, 2015).…”

Determining how biotic and abiotic variables affect the shell condition and parameters of <i>Heliconoides inflatus</i> pteropods from a sediment trap in the Cariaco Basin

“…The link between food availability and shell growth has been proposed for another species of pteropod in the same superfamily as H. inflatus, Limacina retroversa, which was found to form smaller shells when food resources were lim-ited (Meinecke and Wefer, 1990). Furthermore, the availability of food has been found to offset, or even negate, the negative effects of increased pCO 2 levels or low pH in other groups of marine calcifiers such as mussels, oysters, and corals (Heinemann et al, 2012;Hettinger et al, 2013;Kroeker et al, 2016;Ramajo et al, 2016;Thomsen et al, 2013;Towle et al, 2015), presumably because organisms require energy for biomineralization (Palmer, 1992). Feeding rates in calcifiers can also be affected by acidified conditions, with responses varying according to phylum, feeding style, life stage, and exposure time.…”

Assessing annual variability in the shell thickness of the pteropod <i>Heliconoides inflatus</i> in the Cariaco Basin using micro-CT scanning

“…Manno et al, 2017). The impact of predicted future conditions on live specimens has been assessed using wide variety of parameters, including calcification (Comeau et al, 2009(Comeau et al, , 2010Maas et al, 2018;Moya et al, 2016), shell degradation (Bednaršek et al, 2012b;Bergan et al, 2017;Lischka and Riebesell, 2012), metabolic rates (Maas et al, 2011;Seibel et al, 2012), respiration (Comeau et al, 2010;Maas et al, 2018;Moya et al, 2016), and gene expression patterns (Koh et al, 2015;Maas et al, 2015Maas et al, , 2018Moya et al, 2016;Thabet et al, 2017). Generally, previous studies have found that as the aragonite saturation state decreases, pteropod calcification rates decrease (Comeau et al, 2010(Comeau et al, , 2009Lischka and Riebesell, 2012).…”