Geoscience Reference
In-Depth Information
TABLE 4.16
Sediment Denitrification Half-Saturation Concentration
for Nitrate (
µ
M NO 3 )
Method of
Determination
Min.
Max.
Avg.
Location
Reference
As Cited in
Explanation
24
Tokyo Bay,
Japan
Slurry technique
Koike et al.,
1978
Hattori 14
50
San
Francisco
Bay
Slurry technique
Oremland
et al., 1984
Seitzinger 18
20°C
344
Kysing
Fjord,
Denmark
Slurry technique
Oren and
Blackburn,
1979
Seitzinger 18
12°C
53
Izembek
Lagoon,
Alaska
Slurry technique
Iizumi et al.,
1980
Seitzinger 18
11°C−15°C
50
Belgian
coast
Slurry technique
Billen, 1978
Seitzinger 18
27
42
Mangoku-
Ura, Japan
Koike et al.,
1978
Hattori 14
processes, an equilibrium adsorption-desorption assumption can be made. This
equilibrium assumption means that the dissolved and particulate phosphorus phases
“instantaneously” react to any discharge sources of phosphorus, or run-off, or
shoreline erosion of solids so as to redistribute the phosphorus to its “equilibrium”
dissolved and solids phase concentrations. Sorption of inorganic phosphorus onto
particulates and the subsequent particulate settling process are both included in the
transport codes of WASP. The sorption term, therefore, is not included in the
EUTRO5 kinetic equations.
In AQUATOX 73 the phosphorus cycle has only one essential state variable,
orthophosphate. Atmospheric deposition and biota excretion are two phosphate
sources in AQUATOX that are not modeled in WASP/EUTRO5. During decompo-
sition of detritus, only inorganic phosphorus is released, while in EUTRO5 both
inorganic and organic phosphorus are formed. Three types of algae (blue-green,
green, and diatoms) and macrophytes are modeled, each with different phosphate
uptake rates. Macrophytes supply their phosphorus from sediment and excrete phos-
phate to the water column.
The model developed by Park and Kuo 69 uses two state variables (organic and
inorganic phosphorus) for modeling the phosphorus cycle. Similar to the EUTRO5
model, phytoplankton is considered as a single population biomass. Mineralization
rate is a function of organic phosphorus concentration, while in EUTRO5 the min-
eralization rate is a function of both the organic phosphorus and phytoplankton
concentrations present.
 
 
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