Coastal Eutrophication and Marine Benthic Vegetation
16
Dissolved oxygen
4
O~------~--~=-~~-A~~ ______ ~
o
100
200
days
300
400
Surface mixed layer -------- simulation
+ measurement
Bottom mixed layer - - - simulation
• measurement
91
Fig. 3.7. Measured and simulated oxygen concentrations in the surface mixed layer
(SML) and the bottom mixed layer (BML) of Lake Veere (model segments 2 and 8, cf.
Fig. 3.2)
Table 3.1); and (2) the nitrophily of green macro algae (N/P ratio about
25; Sfriso 1987).
The nitrogen limitation in the other two lagoons is even more obvious.
Even though the N/P ratio of the nutrient input was close to or even
higher than the Redfield ratio (Table 3.1), the DIN/DIP ratio
(DIN = dissolved inorganic nitrogen in the form of ammonium and
nitrate) of the winter concentrations was 2-4 in Lake Grevelingen and
7 - 8 in Lake Veere. This nitrogen limitation is partly explained by the
remobilization of phosphorus from the sediment, which had been previously accumulated from the river input during the estuarine history of
the lagoons (Kelderman 1985). Additionally, nitrogen removal by denitrification has been identified as a key process in the nitrogen cycle of
shallow-water marine ecosystems. This process is responsible for the
natural tendency towards N-limitation, and is particularly effective in
water systems with long water residence times (De Vries and Hopstaken
1984; Seitzinger 1987; Smith 1991).
The mass balance analysis therefore focuses on the nitrogen cycle and
evaluation of the phosphorus cycle is omitted.
16
Dissolved oxygen
4
O~------~--~=-~~-A~~ ______ ~
o
100
200
days
300
400
Surface mixed layer -------- simulation
+ measurement
Bottom mixed layer - - - simulation
• measurement
91
Fig. 3.7. Measured and simulated oxygen concentrations in the surface mixed layer
(SML) and the bottom mixed layer (BML) of Lake Veere (model segments 2 and 8, cf.
Fig. 3.2)
Table 3.1); and (2) the nitrophily of green macro algae (N/P ratio about
25; Sfriso 1987).
The nitrogen limitation in the other two lagoons is even more obvious.
Even though the N/P ratio of the nutrient input was close to or even
higher than the Redfield ratio (Table 3.1), the DIN/DIP ratio
(DIN = dissolved inorganic nitrogen in the form of ammonium and
nitrate) of the winter concentrations was 2-4 in Lake Grevelingen and
7 - 8 in Lake Veere. This nitrogen limitation is partly explained by the
remobilization of phosphorus from the sediment, which had been previously accumulated from the river input during the estuarine history of
the lagoons (Kelderman 1985). Additionally, nitrogen removal by denitrification has been identified as a key process in the nitrogen cycle of
shallow-water marine ecosystems. This process is responsible for the
natural tendency towards N-limitation, and is particularly effective in
water systems with long water residence times (De Vries and Hopstaken
1984; Seitzinger 1987; Smith 1991).
The mass balance analysis therefore focuses on the nitrogen cycle and
evaluation of the phosphorus cycle is omitted.