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    Sea ice drift data were obtained from an array of ten ice beacons and one ice mass balance buoy launched from the CCGS Amundsen in the marginal ice zone of the southern Beaufort Sea in September, 2009. From this array, four triangular configurations were selected, hereinafter referred to as triplets A to D, to monitor sea ice deformation with initial inter-beacon distances of approximately 11, 11, 11.5, and 7 km for the shortest leg, and 15, 37, 11.5, and 12.5 km for the longest leg, respectively. Triplets A to D were deployed on multiyear ice (MYI) and labeled according to their proximity to the continental coastline, with Triplet A located closest to the coastline and then sequentially further away through to Triplet D. Position coordinates were available for all beacons in: Triplet A until October 6th; Triplet B until November 4th; Triplet C until November 25th, and Triplet D until November 3rd, yielding time intervals with durations of 28, 56, 77, and 59 days, respectively.

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    An incubation experiment was conducted on board of the Canadian research icebreaker CCGS Amundsen between 6 and 15 August 2015. The water was collected near the nitracline at 38 m depth in Baffin Bay using 12-L Niskin-type bottles deployed on a CTD rosette system. A natural Arctic plankton community in a pre-bloom stage (initial high nutrient-low Chl a concentrations) was exposed over 9 days to reduced pH conditions under two contrasting light regimes. The two light regimes were designed to simulate the mean irradiance in an ice-free 5-m thick surface mixed layer (HL, marginal ice bloom conditions) and the mean irradiance at 5 m depth under a melting ponded ice pack (LL, under-ice bloom/ subsurface chlorophyll maximum conditions). The pH gradient comprised 6 levels covering the range of pH expected between the present and the year 2300. During the incubation, a phytoplankton bloom developed in every incubation bag and diatoms dominated the biomass (Chaetoceros spp.). Temporal variations of pH, dissolved inorganic carbon, total alkalinity, chlorophyll a, macronutrients, DMS(P), flow cytometry (nano- and pico-phytoplankton, bacteria, virus), taxonomy, salinity and incubator's temperature are available.