title: Responses to elevated CO2exposure in a freshwater mussel, Fusconaia flava.
abstract: Freshwater mussels are some of the most imperiled species in North America and are particularly susceptible to environmental change. One environmental disturbance that mussels may encounter that remains understudied is an increase in the partial pressure of CO2(pCO2). The present study quantified the impacts of acute (6 h) and chronic (up to 32 days) exposures to elevated pCO2on genes associated with shell formation (chitin synthase; cs) and the stress response (heat shock protein 70; hsp70) in Fusconaia flava. Oxygen consumption (MO2) was also assessed over the chronic CO2exposure period. Although mussels exhibited an increase in cs following an acute exposure to elevated pCO2, long-term exposure resulted in a decrease in cs mRNA abundance, suggesting that mussels may invest less in shell formation during chronic exposure to elevated pCO2. In response to an acute elevation in pCO2, mussels increased hsp70 mRNA abundance in mantle and adductor muscle and a similar increase was observed in the gill and adductor muscle in response to a chronic elevation in pCO2. A chronic elevation in pCO2also increased mussel MO2. This overall increase in hsp70 mRNA levels and MO2in F. flava indicates that exposure to elevated pCO2initiates activation of the general stress response and an increased energy demand. Together, the results of the present study suggest that freshwater mussels respond to elevated pCO2by increasing processes necessary to 'deal with' the stressor and, over the long-term, may reduce their investment in non-essential processes such as shell growth.
authors.affiliation: Department of Natural Resources and Environmental Science, University of Illinois at Urbana-Champaign, 1102 South Goodwin Avenue, Urbana, IL, 61801, USA. jjeffrey@illinois.edu.
authors.forename: Jennifer D
authors.initials: JD
authors.lastname: Jeffrey
authors.affiliation: Department of Natural Resources and Environmental Science, University of Illinois at Urbana-Champaign, 1102 South Goodwin Avenue, Urbana, IL, 61801, USA.
authors.forename: Kelly D
authors.initials: KD
authors.lastname: Hannan
authors.affiliation: Department of Natural Resources and Environmental Science, University of Illinois at Urbana-Champaign, 1102 South Goodwin Avenue, Urbana, IL, 61801, USA.
authors.forename: Caleb T
authors.initials: CT
authors.lastname: Hasler
authors.affiliation: Department of Natural Resources and Environmental Science, University of Illinois at Urbana-Champaign, 1102 South Goodwin Avenue, Urbana, IL, 61801, USA.
authors.forename: Cory D
authors.initials: CD
authors.lastname: Suski
mesh_terms: D060105:Animal Shells / Q000187:drug effects / Q000254:growth & development; D000818:Animals; D049872:Bivalvia / Q000187:drug effects* / Q000502:physiology; D002245:Carbon Dioxide / Q000494:pharmacology*; D002687:Chitin Synthase / Q000235:genetics; D005618:Fresh Water; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics*; D009132:Muscles / Q000187:drug effects / Q000378:metabolism; D010101:Oxygen Consumption / Q000187:drug effects*; D012333:RNA, Messenger / Q000378:metabolism
chemical_list: D018840:HSP70 Heat-Shock Proteins; D012333:RNA, Messenger; D002245:Carbon Dioxide; D002687:Chitin Synthase
keywords: Bivalve; Chitin synthase; Heat shock protein 70; Metabolic rate