MEPS 484:33-45 (2013)  -  DOI: https://doi.org/10.3354/meps10275

ABSTRACT: Ice-retreat from the Cape Bathurst Polynya occurred in late May and early June 2004, and was quickly followed by a decrease in dissolved nutrient concentration at the sea surface. Concentration plots of NO₃^- versus PO₄^3-, and Si(OH)₄ versus NO₃^- showed the ratios of nutrient uptake in the surface layer were in proportions expected for diatom growth (N:P 13.1:1; Si:N 1.8:1) and that water-column NO₃^- was depleted before PO₄^3- and Si(OH)₄. The temporal changes in integrated nitrate, phosphate and silicate concentrations were well described by logistic models that showed maximum consumption rates of 11.8, 0.82, and 17.8 mmol m^-2 d^-1, respectively, and a total seasonal draw-down of 210 ± 19 mmol NO₃^- m^-2. If we include estimates of NO₃^- supply by advection, nitrification and freshwater dilution, then the amount of NO₃^- consumed could be 25-33% higher. Uptake of NO₃^- above the 1% isolume was balanced by an equivalent (94%) increase in particulate N over a 15 d period beginning at ice break-up. Thus, the amount of particulate spring new production associated with NO₃^- disappearance was estimated to be 16.1 ± 1.5 g C m^-2.

KEY WORDS: Phytoplankton production · Nutrient consumption · New production · Polynya · Nitrate · Phosphate · Silicate · Amundsen Gulf · Arctic Ocean

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Cite this article as: Simpson KG, Tremblay JÉ, Price NM (2013) Nutrient dynamics in the western Canadian Arctic. I. New production in spring inferred from nutrient draw-down in the Cape Bathurst Polynya. Mar Ecol Prog Ser 484:33-45. https://doi.org/10.3354/meps10275 Export citation Share:    Facebook - - linkedIn