Effects of carbon dioxide on juveniles of the freshwater mussel (Lampsilis siliquoidea [Unionidae])

Abstract

Carbon dioxide (CO ) has shown promise as a tool to control movements of invasive Asian carp, but its effects on native freshwater biota have not been well studied. The authors evaluated lethal and sublethal responses of juvenile fatmucket (Lampsilis siliquoidea) mussels to CO at levels (43-269 mg/L, mean concentration) that bracket concentrations effective for deterring carp movement. The 28-d lethal concentration to 50% of the mussels was 87.0 mg/L (95% confidence interval [CI] 78.4-95.9) and at 16-d postexposure, 76.0 mg/L (95% CI 62.9-90.3). A proportional hazards regression model predicted that juveniles could not survive CO concentrations >160 mg/L for more than 2 wk or >100 mg/L CO for more than 30 d. Mean shell growth was significantly lower for mussels that survived CO treatments. Growth during the postexposure period did not differ among treatments, indicating recovery of the mussels. Also, CO caused shell pitting and erosion. Behavioral effects of CO included movement of mussels to the substrate surface and narcotization at the highest concentrations. Mussels in the 110 mg/L mean CO treatment had the most movements in the first 3 d of exposure. If CO is infused continuously as a fish deterrent, concentrations <76 mg/L are recommended to prevent juvenile mussel mortality and shell damage. Mussels may survive and recover from brief exposure to higher concentrations. Environ Toxicol Chem 2017;36:671-681. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.

Lethal and sublethal responses of native mussels (Unionidae: Lampsilis siliquoidea and Lampsilis higginsii) to elevated carbon dioxide

“…These results differ from earlier findings of comparable PE growth in L. siliquoidea across treatments (up to 110 mg•L -1 or ~ 85 000 µatm PCO 2 ; Waller et al 2017). In the same study, PE growth rate of control mussels (L. siliquoidea) was significantly less than the rate during exposure (Waller et al 2017), suggesting that the former rate was influenced by a factor unrelated to CO 2 treatment. Based on growth of control mussels, we suggest that results of the present study are more indicative of shell growth following recovery from CO 2 exposure.…”

“…Few studies have compared the effects of elevated CO on juvenile and adult freshwater mussels and, to our knowledge, no studies have been conducted with U.S. federally listed species. In separate studies, juvenile (~ 6 mo old; Waller et al 2017) and adult (L. siliquoidea) mussels (Hannan et al 2016c) were exposed to elevated CO 2 for 28 d. Juvenile mussels died at 42 000 µatm PCO 2 (Waller et al 2017), whereas adult mussels survived 55 000 µatm PCO 2 (Hannan et al 2016c). Lampsilis siliquoidea is abundant, geographically widespread (Cummings and Cordeiro 2012), and has become a common species for toxicity testing (e.g., Bringolf et al 2007a, b;Wang et al 2007;Wang et al 2011;and others).…”

“…The exposure duration simulates the use of CO 2 as a long-term or seasonal barrier to deter fish movement. Mortality, shell growth, and behavioral responses to CO 2 were measured on both mussel species and provided comparable data to evaluate interspecies differences (L. higginsii vs L. siliquoidea) and intertrial variation in responses of L. siliquoidea (Waller et al 2017). Condition indices and transcriptional responses were limited to L. siliquoidea because both analyses required sacrifice of individuals which we avoided with L. higginsii.…”

Chronic exposure of a freshwater mussel to elevated pCO2: Effects on the control of biomineralization and ion‐regulatory responses

“…Overall, the data from the present study provide a mechanistic understanding of the potential consequences for biomineralization and ion‐regulatory processes of freshwater mussels to elevations in p CO 2 . No mortality occurred over the course of the experimental period in the present study, and similar levels of p CO 2 (42 mg/L) caused low mortality in juvenile L. siliquoidea , indicating that L. siliquoidea were reasonably tolerant to elevations in p CO 2 . However, although survival was not significantly impacted by exposure to 28 d of elevated p CO 2 , sublethal impacts were evident―particularly when mussels were exposed to 50 000 μatm p CO 2 (Figure ).…”

“…This post‐exposure increase in mantle cs mRNA likely provided a compensatory mechanism for alterations in shell formation that may have occurred during p CO 2 exposure. A subsequent fall in mantle cs mRNA after 14 d of recovery further suggests that once the p CO 2 stressor was removed, normal shell formation may resume―as was observed in juvenile L. siliquoidea after 16 d post‐exposure to elevated p CO 2 .…”