Open AccessRespiration and bacterial carbon dynamics in the Amundsen Gulf, western Canadian Arctic
Author(s) -
Nguyen Dan,
Maranger Roxane,
Tremblay JeanÉric,
Gosselin Michel
Publication year - 2012
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2011jc007343
Subject(s) - respiration , primary production , polar night , arctic , ecosystem , environmental science , oceanography , carbon cycle , circumpolar star , ecosystem respiration , atmospheric sciences , environmental chemistry , ecology , chemistry , biology , botany , geology
Respiration rates are fundamental to understanding ecosystem C flux; however, respiration remains poorly characterized in polar oceans. The Circumpolar Flaw Lead (CFL) study provided a unique opportunity to sample the Amundsen Gulf, from November 2007 to July 2008 and follow microbial C dynamics. This study shows that bacterial production (BP) was highly variable, ranging from 0.01 to 2.14 μ g C L −1 d −1 (CV = 192%), whereas the range in community respiration (CR) was more conservative from 3.8 to 44.2 μ g C L −1 d −1 (CV = 55%), with measurable rates throughout the year. The spring‐summer peak in BP preceded the peak in CR suggesting differential predominant control. From May until July, BP was more related to chlorophyll a concentration (r = 0.68) whereas CR was not. Given the observed high variability, BP was the main driver of bacterial growth efficiency (BGE) (r 2 = 0.86). The overall average BGE was low at 4.6%, ranging from 0.20 in winter to a peak of 18.6% during the spring bloom. This study confirms that respiration is an important fate for C in the Amundsen Gulf, and our rate‐based estimates of ecosystem scale CR suggests that considerably more C is respired than could be accounted for by gross primary production (GPP). One of the most plausible explanations for this observed discrepancy is that regenerated primary production is currently underestimated.