The gases N2O and CH4 will be treated in a similar manner to the short-lived trace gases in WG1. However, one significant difference is the increased emphasis on coastal regions and the development of a typology for scaling up individual studies to estimate global fluxes.
Carbon dioxide fluxes in the coastal zone also take high priority. These fluxes are disproportionately large in relation to the spatial extent of coastal areas, because of the high productivity of such seas. Upscaling to global fluxes from regional budgets and individual studies is hindered by the heterogeneity of the coastal zone. Following the example of the LOICZ international programme, WG3 will develop a typology of coastal regions and net CO2 fluxes, and populate this typology with available data. This will provide the mechanism for quantifying a significant unknown in the ocean carbon cycle.
WG3 takes on the task of interpolating and synthesising the open ocean CO2 fugacity measurement database under development by various researchers. The resulting product of global pCO2 can be converted into a flux using the transfer velocity products of WG2. An important part of WG3’s work is to compare estimates of fluxes from observations with those from both atmospheric inversion and oceanic biogeochemistry models.
Understanding how the air–sea flux of CO2 will change in the future is critical to simulations of climate. The ocean has taken up ~30% of the anthropogenic CO2 released to date, but the future rate of intake is unknown. There is an urgency to coordinate experiments that simulate the behaviour of ocean ecosystems in a high CO2 world. Europe leads the field in this activity with the mesocosm experiments (at the Bergen large-scale facility), and there are funding plans in the EU Sixth Framework Programme FP6 CarboOcean, in the United Kingdom and in Germany. However, this activity must expand to include the development of protocols for replication and intercomparison in a manner analogous with the terrestrial carbon community.
Products:
- Database of N2O, CH4 and CO2 sea and air concentration measurements including representation of the coastal zone.
- Typology of coastal regions for scaling local to global fluxes.
- Protocol for mesocosm simulations of ocean ecology in high CO2 conditions, and plans for long-term and large-scale ecosystem manipulations.