Relative Impact of Sea Ice and Temperature Changes on Arctic Marine Production
We performed a series of experiments with a modern Earth system model to determine the relative importance of ice and temperature on the primary production and the air-sea CO2 flux across the Arctic Ocean. Our experiments indicate that the relative impact of ice and temperature is heterogeneous across the Arctic Ocean but, in general, as the climate warms the loss of ice cover will have a larger impact on ocean temperature and primary production than direct temperature changes.
Our study has provided an improved understanding of the importance of sea ice cover and water temperature in controlling marine production. This knowledge will help in predicting the production response to future environmental changes, and in the allocation of time and resources for future model development efforts.
Through its impact on water temperature and sea-ice cover, changes to the global climate system are likely to have large implications for the Arctic marine ecosystems and consequently Arctic marine production and the carbon cycle. Here we performed a series of experiments with a modern Earth system model to determine the relative importance of ice and temperature on the primary production and the air-sea CO2 flux across the Arctic Ocean. We compared model estimates by a validated baseline run to estimates from a model that had been driven with a warmer atmosphere, as well as to predictions from a model that had artificially reduced sea ice. Our experiments indicate that as the climate warms the loss of ice cover will have a larger impact on ocean temperature and primary production than direct temperature changes. The change in carbon fixation by phytoplankton in response to increased temperatures and reduced ice was generally more than a magnitude larger than the changes to CO2 flux, highlighting the importance of fully considering the marine ecosystem when assessing Arctic carbon cycle dynamics.