Open AccessFlux of nitrogen and phosphorus at the water - sediment boundary in a tropical coastal lagoon (Ciénaga Grande de Santa Marta, Colombian Caribbean).
Author(s) -
G. R. Navas-S.,
Sven Zea,
Néstor Hernando Campos
Publication year - 2003
Publication title -
cicimar oceánides
Language(s) - English
Resource type - Journals
eISSN - 2448-9123
pISSN - 1870-0713
DOI - 10.37543/oceanides.v18i2.5
Subject(s) - sediment , water column , biogeochemical cycle , sink (geography) , oceanography , anoxic waters , environmental science , particulates , phosphorus , flux (metallurgy) , nitrogen , hydrology (agriculture) , nutrient , geology , environmental chemistry , ecology , chemistry , geography , geomorphology , biology , cartography , geotechnical engineering , organic chemistry
To evaluate the role of the sediment in the high primary production of a tropical coastal lagoon,"Ciénaga Grande de Santa Marta" (Caribbean, Colombia), the flux of nitrogen and phosphorous (dissolved, inorganic, particulate) in the water-sediment boundary was measured. From 1996 to 1997 sediment cores were incubated in the laboratory and sediment traps were deployed in the field, in two sites contrasted by the influence of fresh and marine waters. The fluxes were spatially and temporally highly variable but did not show clear patterns in their direction and intensity in relation to the sediment or water column characteristics at the two sites. This evidences a high heterogeneity in the nature and activity of the organisms responsible of the biogeochemical processes. The sediments liberated to the water on average 1643 µmolNm-2d-1 of ammonium and 1.3 µmolNm-2d-1 of nitrite, offering 1.90-3.41 % of the amount required in production. In normal oxic conditions, the sediment acted as a phosphorous sink, absorbing on average 178 µmolPm-2d-1dissolved and receiving 36277 µmolPm-2d-1 particulate. But the phosphorous is maintained in excess in the column, in part, due to its liberation from the sediment in anoxic conditions during massive algal blooms.