The distribution of dissolved and total dissolvable aluminum in the Beaufort Sea and Canada Basin region of the Arctic Ocean

Abstract

21 . Near surface maxima at this time were associated with relatively fresh surface waters (26-30) resulting from sea-ice melt in the region. This observation supports sea ice with entrained sediments and surface deposition of aerosols as important mechanisms for the delivery of Al to surface waters of the Canada Basin. No correlation between D-Al and silicic acid was observed and low D-Al:Si ratios in waters >300 m depth suggest that Al is likely lost through particle scavenging in the interior of the Canada Basin. Concentrations of T-Al show that particulate Al (>0.2 mm) is the dominant form of Al in the water column except at greater depths at the most offshore stations. Lateral transport of D-Al and T-Al off the shelf likely results from the offshore progression of cyclonic eddies spawned inshore, oscillating upwelling and downwelling favorable winds, and brine rejection during sea-ice formation that can drive currents sufficiently energetic to resuspend shelf sediments.

Silica diagenesis and benthic fluxes in the Arctic Ocean

“…Linear DSi gradients were fitted through data points directly below (1-3 cm depth) and, where available, above the undisturbed sediment-water interface in the MUCs. Where no bottom water DSi concentrations were analysed directly, values from Middag et al (2009) and Giesbrecht et al (2013) were adopted for deep water masses in the Eurasian and Canada Basins, respectively. The diffusion coefficient of DSi at a temperature of 2°C was corrected for sediment tortuosity following Archie's Law (Boudreau, 1996).…”

Dissolved gallium in the Beaufort Sea of the Western Arctic Ocean: A GEOTRACES cruise in the International Polar Year

“…1) sampled aboard the CCGS Amundsen in September 2009, a GEOTRACES cruise supporting the International Polar Year (Melling et al, 2012). Seawater was collected with GoFlo bottles attached to a trace metal clean rosette supported by a conducting Kevlar line (Giesbrecht et al, 2013), filtered into acid cleaned LDPE bottles utilizing trace metal clean practices, and acidified onboard the ship in a laminar flow hood.…”

“…9a). Increasing concentrations of dissolved Al in the Arctic with depth may result from reversible exchange (Giesbrecht et al, 2013) or links with the silica cycle (Middag et al, 2009). Increasing trace metal concentrations with depth, similar to Al Fig.…”

“…Trace metal research in the Arctic Ocean has benefitted from the GEOTRACES program and the International Polar Year (Henderson et al, 2007;Melling et al, 2012), including observation of hydrothermal inputs of Mn (Middag et al, 2011) and Fe (Klunder et al, 2012), confirmation of dissolved Al concentration profiles unique to the Arctic (Giesbrecht et al, 2013;Moore, 1989;Middag et al, 2009), and classic Fe limitation of phytoplankton (de Baar et al, 2005) is shown to be paired with light limitation in the Arctic (Taylor et al, 2013). However, dissolved Ga has not been reported in the Arctic Ocean.…”

“…Ga (this study, Station L2), Al Central Arctic(Moore, 1989), Al Beaufort Sea(Giesbrecht et al, 2013), Al Eastern Arctic(Middag et al, 2009).…”