Award: OCE-1041081

It is well established that carbon dioxide (CO2) concentrations in the ocean are increasing as a consequence of rising CO2 levels in the atmosphere. Due to a series of chemical reactions in seawater, higher CO2 concentrations result in a lower pH, more acidic surface ocean. This National Science Foundation award addresses concerns about the long term effects of this change on marine life. Research supported by this award investigated whether lower seawater acidity would affect planktonic animals that support the marine food web in the coastal and deep North Atlantic Ocean. One species of zooplankton, the planktonic marine copepod, Calanus finmarchicus, is particularly important in coastal ocean food webs on both sides of the North Atlantic Ocean. This energy rich species, about the size of a grain of rice, is the primary prey for herring and other forage fish as well as for the endangered northern right whale in the productive ecosystems of the Gulf of Maine including Georges Bank. It is also the foundation species supporting herring, cod and other groundfish species in the Norwegian Sea. A series of experiments conducted at the Darling Marine Center, University of Maine, and with Norwegian colleagues at the Austevoll Research Station near Bergen, Norway, did not find any significant effects of increased CO2/lower pH levels predicted to occur over the next century. C. finmarchicus grew just as well in tanks at pH 7.6 (the most severe prediction for year 2100) as in tanks using ocean water at todayÆs present CO2 concentrations. The species' feeding rates, growth rates, metabolism and the hatching success of its eggs were not signficantly different between the present day and representative future CO2/pH conditions. In the Gulf of Maine, C. finmarchicus resides at the southern edge of its subarctic range. Over the past decade, temperatures have been warming in the Gulf of Maine at a rate that is 10-20 times faster than the average over the past century. Research supported by this award indicates that rising temperature, changes to transport from Canadian waters where Calanus is abundant and the timing of winter-spring blooms of planktonic algae will be more important than ocean acidification in determining whether this key species will persist in the Gulf of Maine in the coming decades. Last Modified: 01/28/2015 Submitted by: Jeffrey Runge