Journal of the korean society of oceanography

The Korean Society of Oceanography (한국해양학회)
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Diel Cycles of Nitrogen Uptake by Marine Phytoplankton in NO$_3^-$-high and -low Environments

  • Park, Myung-Gil (Department of Oceanography and Research Institute of Oceanography,Seoul National University) ;
  • Shim, Jae-Hyung (Department of Oceanography and Research Institute of Oceanography,Seoul National University) ;
  • Yang, Sung-Ryull (Department of Environmental Engineering, Kwangju University) ;
  • Lee, Sang-Hoon (Polar Research Center, Korea Ocean Research and Development Institute) ;
  • Cho, Byung-Cheol (Department of Oceanography and Research Institute of Oceanography,Seoul National University)
  • Published : 1997.12.31
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Abstract

To test the roles of NO$_3^-$ concentration and light as controlling factors of NO$_3^-$ uptake in the NO$_3^-$-low and -high environments and to assess the significance of night-time nitrogen (N) uptake in estimating the daily N uptake rate, 2 diel studies of N uptake were conducted in NO$_3^-$-low (the eastern part of the Yellow Sea) and NO$_3^-$-high (the marginal ice zone of the northwestern Weddell Sea) environments on June 14 to 15, 1996 and January 15 to 16, 1995, respectively. Ourobservations confirmed that NO$_3\;^-$ uptake by phytoplankton is mainly determined by ambient NO$_3^-$ concentration in NO$_3^-$-low environment and by light in NO$_3^-$-high environment, respectively, Our results suggest the need for diel studies to accurately estimate the daily N uptake rates and thus new and regenerated production because the daily rates calculated without considering the night-time N uptake would be significantly underestimated (up to 41%), particularly in the NO$_3^-$-low environment.

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