Resilience of Atlantic Slippersnail Crepidula fornicata Larvae in the Face of Severe Coastal Acidification

Abstract

12Globally, average oceanic pH is dropping, and it will continue to decline into the foreseeable 13 future. This ocean acidification (OA) will exacerbate the natural fluctuations in pH that nearshore 14 ecosystems currently experience daily, potentially pushing marine organisms to their physiological 15 limits. Adults of Crepidula fornicata (the Atlantic slippersnail) have proven remarkably resilient to 16 many environmental changes, which is perhaps not surprising considering that they are common 17 intertidally, have a geographically large native range, and have been extremely successful at invading 18 coastal water in many other parts of the world. However, the larvae of C. fornicata have been shown 19 to be somewhat more vulnerable than adults to the effects of reduced pH. Research to date has focused 20 on the physiological impacts of OA on C. fornicata larvae; few studies have explored shifts in gene 21 expression resulting from changes in pH. In the present study, we examined the response of young (4-22 day old) C. fornicata larvae to two extreme OA treatments (pH 7.5 and 7.6) relative to pH 8.0, 23 documenting both phenotypic and genome-wide gene expression responses. We found that rearing 24 larvae at reduced pH had subtle influences on gene expression, predominantly involving 25 downregulation of genes related to growth and metabolism, accompanied by significantly reduced shell 26 growth rates only for larvae reared at pH 7.5. Additionally, 10-day old larvae that had been reared at 27 the two lower pH levels were far less likely to metamorphose within six hours when exposed to inducer. 28However, all larvae eventually reached similarly high levels of metamorphosis 24 hours after 29 settlement induction. Finally, there were no observed impacts of OA on larval mortality. Taken 30 together, our results indicate that far future OA levels have observable, but not severe, impacts on C. 31 fornicata larvae, which is consistent with the resilience of this invasive snail across rapidly changing 32 nearshore ecosystems. We propose that future work should delve further into the physiological and 33 transcriptomic responses of all life history stages to gain a more comprehensive understanding of how 34 OA impacts the intertidal gastropod C. fornicata. 35

Ocean acidification promotes broad transcriptomic responses in marine metazoans: a literature survey

“…However, differences in larval oxygen consumption are evident as they develop into mature feeding larvae, eventually displaying increases in metabolic rate under elevated pCO 2 (1318 μatm) [84]. Larval growth rate and metamorphosis at 6 h post hatching is delayed in the Atlantic slippersnail, Crepidula fornicata, under high pCO 2 (1480 μatm), which coincides with an overall transcriptomic depression, including downregulation of multiple GO categories associated with metabolism and growth [64].…”

Parental whole life cycle exposure modulates progeny responses to ocean acidification in slipper limpets

“…Our previous acute exposure experiment (14 days) showed that C . onyx was resilient to OA stress, and observations on the conspecific C. fornicata also suggest similar trends (Kriefall et al, 2018; Noisette et al, 2016). Collected from a coastal site where present‐day pH ranged from pH 7.6 to 8.2, larval C .…”

“…Non-genetic mechanisms that confer resilience include changes in gamete quality and quantity (Foo & Byrne, 2017;Vehmaa et al, 2012); transfer of macromolecules, for example, protective chaperone proteins (Wang et al, 2018), and microbiota (Chen et al, 2018); as well as, epigenetic variations, for example, DNA methylation, miRNAs, and chromatin modifications (Eirin-Lopez & Putnam, 2019). Our previous acute exposure experiment (14 days) showed that C. onyx was resilient to OA stress, and observations on the conspecific C. fornicata also suggest similar trends (Kriefall et al, 2018;Noisette et al, 2016). Collected from a coastal site where present-day pH ranged from pH 7.6 to 8.2, larval C. onyx showed a high degree of behavioral plasticity, increasing their clearance rate and settling faster, when exposed to OA conditions (Maboloc & Chan, 2017).…”

TagSeq for gene expression in non-model plants: a pilot study at the Santa Rita Experimental Range NEON core site

“…Many subsequent studies have successfully used a similar approach in other non-model animals (e.g. Kenkel and Matz, 2016;Dixon et al, 2018;Kriefall et al, 2018;Rocker et al, 2019) . In plants, however, TagSeq studies to date appear to have been confined to model species for which a high quality reference genome is available (Meyer et al, 2014;Des Marais et al, 2015;Lovell et al, 2016;Kremling et al, 2018;Chu et al, 2019;Razzaque et al, 2019;Weng et al, 2019) .…”