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Influence of carbon availability on dentrification in the central Baltic Sea
Author(s) -
Brettar Ingrid,
Rheinheimer Gerhard
Publication year - 1992
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1992.37.6.1146
Subject(s) - baltic sea , environmental science , oceanography , carbon fibers , carbon cycle , ecology , geology , ecosystem , biology , materials science , composite number , composite material
Denitrification was investigated in the Baltic proper at two stations with different conditions in the deep water. The Gotland Deep was examined as an example of a basin with anoxic, H 2 S‐containing deep water and station T was taken as an example of low‐oxygen (<0.2 ml liter −1 ), sulfide‐free deep water. Denitrification was measured by the acetylene blockage method; in addition, N 2 O reduction was followed in samples without acetylene. To shed light on the factors limiting denitrification, we compared in situ rates to denitrification after adding nitrate or electron donors. Denitrification was restricted to the layer of the oxic‐anoxic interface in the Gotland Deep and to the water layer near the sediment of station T. For both stations it could be shown that denitrification was not limited by nitrate availability. A lack of available organic C seemed to limit denitrification rates and growth of denitrifiers. As a result of C limitation in the water column, denitrification was restricted to energy‐rich interfaces. In the low‐oxygen water away from energy‐rich interfaces, the less C‐demanding nitrification‐denitrification coupling (NH 4 + → N 2 O → N 2 ) seemed to be favored. Denitrification in the water of the central Baltic seems to be subjected to strong variability due to changing C supply during the course of the year. However, limitation by C availability can be assumed for most of the year and should be taken into account in calculating the N budget of the Baltic.