Seasonal distribution and activity of nitrogen-cycling bacteria in Bardawil Lagoon, Egypt

  • A Dewedar
  • M Bahgat
  • EE Shabana

Abstract

The ecological significance of Bardawil Lagoon, the only oligotrophic hypersaline lagoon on the Mediterranean coast of Egypt, was assessed through studying counts, activities and the distribution of nitrogen-cycling bacteria. Counts  and activities of ammonifying bacteria, ammonium-oxidising microbes (AOM) and nitrite-oxidising bacteria (NOB) were compared between sites colonised by macrophytes and bare sites. Microbial counts and activities, and the concentrations of both organic and inorganic nitrogen compounds, were higher at colonised sites. In late summer, as macrophytes started to die off, organic nitrogen content in the sediments increased, mineralisation of the organic nitrogen in the sediments was pronounced, and ammoniacal-N, nitrate-N and nitrite-N concentrations peaked. Counts of ammonifying  bacteria, AOM and NOB were also at maximum during the same period, coinciding with the highest ammonification and nitrification rates.

Keywords: ammonification; nitrification; macrophytes; saline lake; sediment

African Journal of Aquatic Science 2009, 34(2): 183–188

Author Biographies

A Dewedar
Department of Botany, Suez Canal University, Ismailia, Egypt
M Bahgat
Faculty of Sciences, Suez Canal University, Port Said, Egypt
EE Shabana
Department of Botany, Suez Canal University, Ismailia, Egypt
Section
Articles

Journal Identifiers


eISSN: 1727-9364
print ISSN: 1608-5914