This study examined possible environmental factors that affect prokaryote variables in surface waters (upper 100 m of water
column) in the Canada Basin, western Arctic Ocean. We collected data on prokaryote abundance and heterotrophic production
([
3H]leucine incorporation) at eight stations deployed along a slope-to-offshore transect during September 2009. Prokaryote production
and growth tended to increase with increasing chlorophyll
a (Chl.
a) and temperature and with decreasing salinity. The combination of Chl.
a, temperature, and salinity accounted for a large fraction (74%) of the variability in prokaryote production, with the highest
contribution made by Chl.
a (
r
2 = 0.56), followed by salinity (
r
2 = 0.14) and temperature (
r
2 = 0.03). Similarly, the variability in prokaryote growth rate was largely accounted for by the combination of the three environmental
variables (overall
r
2 of 0.64), with Chl.
a making the largest contribution to variability (
r
2 = 0.33), followed by salinity (
r
2 = 0.27) and temperature (
r
2 = 0.05). These data are consistent with the notion that organic matter supply associated with freshwater inputs to surface
layers can result in enhanced prokaryote production and growth in the Canada Basin. Our results provide insights into the
regulation of the microbial loop in the Canada Basin where freshening has been proceeding rapidly due to increasing river
discharge and sea-ice melting.
相似文献