Ocean Acidification-Category 1- Impact of ocean acidification on survival of early life stages of planktonic copepods in the genus Calanus in the northern

• Main Authors: Runge, Jeffrey A., Christensen, John P.
• Format: Text
• Language: unknown
• Published: DigitalCommons@UMaine 2015
• Subjects: Biological Oceanography; Population Dynamics; Biogeochemical cycles; Biogeochemistry; Oceanography; Arctic; Arctic Ocean; North Atlantic; Ocean acidification; Copepods
• Online Access: https://digitalcommons.library.umaine.edu/orsp_reports/365; https://digitalcommons.library.umaine.edu/cgi/viewcontent.cgi?article=1371&context=orsp_reports

While attention concerning impacts of predicted acidification of the world's oceans has focused on calcifying organisms, non-calcifying plankton may also be vulnerable. In this project, the investigator will evaluate the potential for impacts of ocean acidification on the reproductive success of three species of planktonic copepods in the genus Calanus that are prominent in high latitude oceans. C. finmarchicus dominates the mesozooplankton biomass across much of the coastal and deep North Atlantic Ocean. C. glacialis and the larger C. hyperboreus are among the most abundant planktonic copepods in the Arctic Ocean. Previous research showed that hatching success of C. finmarchicus eggs was severely inhibited by increased CO2 and lower pH in seawater, but only tested at an extreme level. Preliminary results in the investigator's laboratory indicate that hatching success of C. finmarchicus is substantially reduced at increased seawater CO2 concentrations corresponding to pH levels between 7.9 and 7.5. Predictions of likely decline of surface pH levels to 7.7-7.8 over the next century raise questions about impacts on Calanus population dynamics if these preliminary results are confirmed. C. finmarchicus, for example, is presently at the southern edge of its range in the Gulf of Maine. The combination of higher surface layer temperature and lower pH may inhibit reproductive success during the late summer/fall bloom, which the PI hypothesize is critical to sustain the overwintering stock in this region. The investigators will collect C. finmarchicus females from the Gulf of Maine and, with the assistance of Canadian colleagues, C. glacialis and C. hyperboreus females from the deep lower St. Lawrence Estuary. They will conduct laboratory experiments in which hatching success, development and growth of Calanus nauplius stages are measured in controls of natural seawater and at a series of treatments in which CO2 concentrations, pH and temperature are rigorously controlled to represent possible future states of the ...