Inter-Research > MEPS > v484 > p33-45  

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

Nutrient dynamics in the western Canadian Arctic. I. New production in spring inferred from nutrient draw-down in the Cape Bathurst Polynya

Kyle G. Simpson1,2,*, Jean-Éric Tremblay1,3, Neil M. Price

1Department of Biology, 1205 Ave. Dr. Penfield, McGill University, Montréal, Québec H3A 1B1, Canada
2Present address: Institute of Ocean Sciences, Fisheries & Oceans Canada, PO Box 6000, 9860 West Saanich Road, Sidney, British Columbia V8L 4B2, Canada
3Present address: Département de Biologie, Université Laval, Québec, Québec G1K 7P4, Canada

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 PO43-, 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 PO43- 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

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