The goal of the proposed study is to establish an Arctic Observing Network (AON) for sea surface partial pressure of CO2 (pCO2) and pH in the perennially ice-covered portion of the Arctic Ocean. The carbon cycle is of particular concern in the Arctic because it is unknown how carbon sources and sinks will change in response to warming and the reduction of summer sea ice cover, and whether these changes will lead to increased greenhouse gas accumulation in the atmosphere. Furthermore, the penetration of anthropogenic CO2 into the Arctic Ocean is leading to acidification with potentially serious consequences for organisms. Little is known about pCO2 and the inorganic carbon cycle in the central Arctic Ocean because most measurement programs to date have focused on the Arctic shelves during the accessible summer period. The investigators propose to use an existing component of the Arctic Observing Network, the Ice-Tethered Profilers (ITP), as platforms for deployment of in situ pCO2 and pH sensors. ITPs are automated profiling systems distributed throughout the perennial Arctic ice pack that telemeter data back to shore: 44 ITPs have been deployed since 2004 and the project is currently slated to continue through 2013. In the proposed work, a total of 6 ITPs will be equipped with CO2 sensors and four of these will also have pH sensors. The sensors will be fixed on the ITP cable ~2-4 m below the ice. Each unit will include additional sensors for dissolved O2, salinity, and photosynthetically available radiation (and in some cases chlorophyll-a fluorescence) and will be capable of making 12 measurements per day for at least one year. These data, available in near real-time on the ITP web site (www.whoi.edu/itp/), will lead to a better understanding of the Arctic Ocean's role in regulating greenhouse gases and how the ecology of the Arctic will change with warming and acidification. The investigators will also engage in outreach programs including public presentations, podcasts, and school visits. A portion of the budget is also dedicated to the development of a climate-change/ocean acidification exhibit to be displayed in the University of Montana?s science museum. The exhibit will reside at the museum for three months, then visit over 15 rural and tribal communities annually over a three year period. Undergraduate students will be recruited to assist with the sensor testing and data analysis, gaining a higher level of technical knowledge than possible through a traditional degree program.
The major goal of this study (a collaborative project led by Dr. Michael DeGrandpre of the U. Montana) was to initiate an Arctic Observing Network (AON) for sea surface partial pressure of CO2 (pCO2) and pH in the perennially ice-covered sector of the Arctic Ocean. Global warming and other climate-related processes are rapidly changing the Arctic Ocean. Summer sea-ice is disappearing and the sea surface is warming and freshening. This changing physical environment is, in turn, altering biological productivity, biogeochemical cycles, and air-sea fluxes. The carbon cycle is of particular concern in the Arctic because it is not known how carbon sources and sinks will change in the future, and whether these changes will lead to increased greenhouse gas accumulation in the atmosphere. Furthermore, the penetration of anthropogenic CO2 into the Arctic Ocean is leading to acidification with potentially fatal consequences for calcium-carbonate- forming organisms. Not much is known about pCO2 and the inorganic carbon cycle in the central Arctic Ocean basins; it is critical to act quickly to more widely measure pCO2 and related parameters and document any change. To date, nearly all measurement programs have been focused on the Arctic shelves during the accessible summer period, but we now have the technology to measure CO2 in remote locations during the harsh Arctic winter. In this Arctic Observing Network project, Ice-Tethered Profilers (ITP) AON (www.whoi.edu/itp/) are being used as platforms for supporting in situ pCO2 and pH sensors. ITPs are automated profiling systems that sample and report temperature and salinity and in some cases dissolved O2 and bio-optical parameters, to depths up to ~750 m. They telemeter data back to WHOI where the observations are made available on the ITP web site in near real time. Post-processing yields final calibrated, edited data sets that are also made available from WHOI and are submitted to national data archives. The present project supported addition of Submersible Autonomous Moored Instrument (SAMI) CO2 and pH sensors on ITP tethers just below the ice-ocean interface, and integration of their data into the ITP telemetry stream. The WHOI component of this collaborative project focused on the data integration element (electronics and software), which was successfully carried out. A total of 7 ITP systems were augmented with SAMI units and deployed throughout the Arctic during the grant period. Despite some instrumental problems with the SAMIs, the data obtained from these sensors are enabling scientists to better understand how the evolving sea ice distribution and air-sea exchange is impacting the accumulation of anthropogenic CO2 in the atmosphere and how CO2 absorption by sea water is changing the pH (acidification) of the Arctic Ocean.