Location of Repository

The effect of organic carbon and nitrogen additions on inorganic nitrogen uptake by phytoplankton and bacteria

By Kim Van Wijk

Abstract

Bibliography: pages 76-89.This study examines the effects of enrichment with organic carbon and nitrogen on inorganic nitrogen partitioning between phyto- and bacterio- plankton. Strongly preferential uptake of ammonium over nitrate was observed by both the phytoplanktonic and bacterial fractions, with RPINH4 values typically between 1 and 5. The bacterial fraction ( <0.8μm) was found to be responsible for as much as 48-75% of community uptake of ammonium; while the netplanktonic fraction was observed to take up approximately 50% of intact community uptake of nitrate. The addition of amino acids appeared to mediate bacterial competition for ammonium, indicating their preference for DON as a nitrogen source and allowing increased ammonium uptake by the nanoplanktonic fraction. The effect of glucose enrichment was complicated by the presence of protozoans, which appeared to be indirectly responsible for decreased ammonium uptake due to depletion of this substrate in the presence of added glucose. The nanoplankton appeared to be responsible for the least nitrogen uptake with respect to biomass, indicating that they may have been subject to competition pressure from both the bacterial and netplanktonic fractions

Topics: Phytoplankton
Publisher: Department of Oceanography
Year: 1991
OAI identifier: oai:open.uct.ac.za:11427/18342
Download PDF:
Sorry, we are unable to provide the full text but you may find it at the following location(s):
  • http://hdl.handle.net/11427/18... (external link)
  • Suggested articles

    Preview


    To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.