This dataset consists of vertical profiles of discrete depth sampled weekly at a fixed station under the ice in Franklin Bay (Southeastern Beaufort Sea) for chlorophyll a concentration of different size fractions: >0.7µm and >5µm. Sampling took place from December 2003 to May 2004 through the moon-pool of the CCGS Amundsen for depth ranging from 10m to the bottom and through a hole in the ice cover for the surface depth (3-10m). Chlorophyll a concentrations were determined by fluorimetry.

The CTD data was obtained during LEG 06 of the 2004 CASES scientific cruise #0403. This Leg was carried out from March 31th 2004 to May 12th 2004 aboard the CCGS Amundsen. There were 91 CTD casts in Leg 6. All of these casts, associated to the overwintering oceanographic station, are located in Beaufort Sea research area. The following parameters were measured: temperature, conductivity and pressure (with a Sea-Bird 911 probe), oxygen (Sea-Bird 43), pH (Seabird 18), fluorescence (Seapoint fluorometer), nitrates (Satlantic MBARI ISUS), transmittance (Wetlabs C-Star transmissometer), PAR/Irradiance and SPAR/Irradiance (Biospherical Instruments QC2300). Data were quality controlled. Data are available on the Polar Data Catalogue and at the Marine Environmental Data Service (MEDS) of Fisheries and Ocean Canada.

The CTD data was obtained during LEG 04 of the 2004 CASES scientific cruise #0401. This Leg was carried out from January 7th 2004 to February 18th 2004 aboard the CCGS Amundsen. There were 119 CTD casts in Leg 4. All of these casts, associated to the overwintering oceanographic station, are located in Beaufort Sea research area. The following parameters were measured: temperature, conductivity and pressure (with a Sea-Bird 911 probe), oxygen (Sea-Bird 43), pH (Seabird 18), fluorescence (Seapoint fluorometer), nitrates (Satlantic MBARI ISUS), transmittance (Wetlabs C-Star transmissometer), PAR/Irradiance and SPAR/Irradiance (Biospherical Instruments QC2300). Data were quality controlled. Data are available on the Polar Data Catalogue and at the Marine Environmental Data Service (MEDS) of Fisheries and Ocean Canada.