Towards Long-term Monitoring of the CO2 System in Arctic Rivers


Arctic Research Initiative
2009 Funded Project


The CO2 system (pH, pCO2, DIC, and TAlk) in rivers and their estuaries plays a critical role in regulating fluxes of inorganic carbon, including CO2, into and out of these aqueous ecosystems, and yet these systems remain heavily understudied, particularly for high latitude drainage basins.  Currently, we do not have a clear understanding of how much riverine and estuarine systems contribute to the global CO2 budget, and therefore are unable to make reasonable projections on how these systems will respond, or contribute to, rising atmospheric CO2 concentrations that serves as a primary driver of global climate change.  Previous measurements of the CO2 system in Arctic rivers and their estuaries are grossly inadequate relative to those for the open ocean.  In particular, we lack information on long-term trends and short-term variations in fluvial CO2 system dynamics, which are essential to predict how these systems, as well as their estuaries and adjacent coastal waters, respond to accelerated climate change in Arctic region. 

The Arctic Ocean receives large riverine fluxes of organic matter, suspended material, and nutrients from surrounding rivers, with this riverine influence being the most substantial among all major ocean basins.  The Arctic is also considered particularly sensitive to global climate change.  The CO2 system in Arctic rivers will likely undergo a significant and observable change within a relatively short time period (decades).  As temperature- and hydrologicallydriven weathering processes increase and permafrost destabilizes in the Arctic, fluvial inorganic carbon fluxes is also likely to increase.  This may have significant impacts on riverine and coastal carbon cycles, and related ecosystem functioning.  The expected increase in riverine organic carbon flux from Arctic drainage basins may enhance organic carbon degradation and microbial respiration, both of which may drive aqueous CO2 level towards over-saturation, and thus release more CO2 to the atmosphere.  To study these potential changes in Arctic rivers, both long-term and short-term measurements are required.  

I propose to initiate time-series measurements of the CO2 system in the Mackenzie River, the major Arctic river in North America.  The field campaigns will include both diurnal and monthly sampling of all primary CO2 system parameters in river water.  All measurements will be performed at high precision and accuracy using state-of-art instrumentation and analytical techniques that the PI is both familiar with and has helped to develop.  This work will serve as the initial step towards long-term measurements and studies of the impacts of global warming on the CO2 systems in Arctic rivers, their estuaries, and adjacent coastal waters.  In order to enhance information content, the PI will coordinate his sampling campaigns with ongoing research programs in the Mackenzie River basin, and will also help existing activities by undertaking samples for other WHOI researchers.  This cost-efficient approach will both maximize the scientific output from this project and lay the foundation for more in-depth studies.  In particular, the award will give the PI (a new Assistant Scientist in MC&G) valuable leverage and preliminary data to justify funding for long-term observations of biogeochemical changes in the Arctic.  This study will also complement existing WHOI ARI research programs, as well as the on-going Arctic-GRO program of the Woods Hole Research Center, and will provide a unique opportunity for the PI to establish long-term collaborations with WHOI and non-WHOI scientists interested in the Arctic research.