Arctic-ICE is a long term landfast sea ice-based project near Resolute Bay, Nunavut, Canada. It is hypothesized that the timing of primary production will dictate the extent of ice-pelagic-benthic coupling in the ice-covered ecosystem and therefore will provide a sensitive indicator of directional change for the system as a whole. The underlying objective of this project is to determine the physical-biological processes controlling the timing of primary production and their influence on the drawdown/release of climatically active gases. The project is split into the following sub-projects: 1) Physical oceanography; 2) Atmosphere-sea ice fluxes and the thermodynamic state of sea ice; 3) Ice algae and under-ice production as ecological indicators of ecosystem structure and function; and 4) Microbial processes influencing climatically active gases. Spring field campaigns have already taken place in 2010 and 2011, with planned campaigns every second year into the foreseeable future.

The monitoring and process studies for this work require a time series (i.e., single location) component for which the landfast sea ice found in Resolute Passage provides a perfect natural laboratory. Field campaigns take place in a small ice camp (2-4 tents) approximately 5-8 km from the Polar Continental Shelf Project (PCSP) base near the Resolute Bay airport. PCSP of Natural Resources Canada has provided much needed logistical support in past field campaigns. Our research is largely student driven and has been split into a set of sub-projects for which data collection and purpose are briefly described below.

1. 1)Physical oceanography: In this sub-project, we seek to better document incoming, outgoing and locally modified water mass characteristics in Resolute Passage. Data collection involves: regular water column profiles using a conductivity (salinity), temperature and depth (CTD) sensor with attached nutrient and biological (fluorescence) sensors; and fine scale vertical structure of currents measured via acoustic Doppler current profilers (ADCP) installed on the undersurface of the sea ice looking down. Moored tethers monitoring light transmission, salinity, and temperature are also installed at specific depths below the ice.
   

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2. 2)Atmosphere-sea ice fluxes and the thermodynamic state of sea ice: In this sub-project, we monitor the surface energy balance and seek to better understand the flux of CO2 between the atmosphere and sea ice in conjunction with monitoring the seasonal freeze-melt cycle of the sea ice cover. Various sensors have been used to monitor the air-ice flux of CO2 including: an autonomous eddy-correlation flux and meteorological station equipped to monitor the surface energy balance, thermal state of the sea ice and air-surface CO2 exchange dynamics; automated chamber flux systems; and peeper pCO2 systems. Another novel instrument employed is a 3D mapping LIDAR system used to monitor the evolution of the sea ice cover during melt. Regular sampling of the sea ice is also used to measure snow and ice physical and biogeochemical properties including vertical profiles of ice microstructure, brine volume and components of carbon equilibrium chemistry (dissolved inorganic carbon, total alkalinity, pCO2).
   

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3. 3)Ice algae and under-ice production as ecological indicators of ecosystem structure and function: The transfer of carbon from ice algae to the pelagic or benthic food webs has been suggested to depend upon the timing of ice algal release into the water column and therefore, represent a strong ecological indicator of the polar marine ecosystem structure and function. Furthermore, most studies assessing annual primary production in ice-covered seas have assumed under-ice production to be nil due to the low transmission of irradiance through the snow, ice and ice algae layer. However, a handful of studies have documented phytoplankton to grow under 100% ice cover during advanced stages of ice melt. In this sub-project we monitor ice algae and water column biomass over time through spectral transmitted irradiance measurements and regular sampling of the sea ice cover and water column via ice core extraction and Niskin water samplers, respectively. Furthermore, automated sediment traps are installed to examine what type, how much and when organic matter is settling in the water column. Measurements are coupled with other sub-projects to examine the biophysical processes influencing the accumulation and release of algae from the ice cover and the development of an under-ice bloom.
   

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4. 4)Microbial processes influencing climatically active gases: Dimethylsulfide (DMS) and nitrous oxide (N2O) are important biogenic climatically active gases contributing to the regulation of the Earth’s climate. Our objective of this sub-project is to understand the complex system responsible for DMS and N2O production in the Arctic and how it will be affected by changes in biophysical processes associated with the thermal evolution of the ice cover. To meet this objective, we undertake regular sampling of the sea ice cover via ice core extraction and of the underlying water column. Samples are measured for DMS, DMSP, dimethylsulfoxide (DMSO) and N2O. In addition to collaboration with the rest of the sub-projects, bacterial abundance is monitored in both the sea ice and water column.
   

Most photos by M. Fischer