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Shifts in biological productivity inferred from nutrient drawdown in the southern Beaufort Sea (2003–2011) and northern Baffin Bay (1997–2011), Canadian Arctic
Author(s) -
Bergeron Myriam,
Tremblay JeanÉric
Publication year - 2014
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2014gl059649
Subject(s) - bay , oceanography , beaufort sea , arctic , productivity , drawdown (hydrology) , environmental science , the arctic , fishery , beaufort scale , geology , geotechnical engineering , aquifer , groundwater , biology , economics , macroeconomics
This paper reports the first in situ evidence of change in the net biological productivity of high‐latitude western Arctic seas. Estimates of seasonal drawdown for major plant nutrients show that net community production (NCP) shifted differently in two contrasted Canadian oceanographic settings. In the stratified southeast Beaufort Sea, seasonal nitrate consumption increased 1.6‐fold between 2003–2004 and 2010–2011. The concomitant thickening of the nitrate‐depleted layer in summer/fall implies that subsurface chlorophyll maxima now consume nutrients over a larger extent of the water column. Meanwhile, nitrate consumption in the once productive North Water Polynya declined by 65% and is now nearly on par with the oligotrophic coastal Beaufort Sea. This decline is attributed to freshening and increased stratification. Commensurate changes in silicate and phosphate drawdown in the two regions indicate that diatoms drove the spatial and temporal shifts in NCP.