78
Luis Felipe Niencheski . Maria da Gra~a Baumgarten· Gilberto Fillmann . Herbert L. Windom
Fig. 4.7. Ammonium concen35
trations plotted against total
(~~:~ . . :.
suspended matter. The points
30
inside the circles are the result
of the strong south winds. The
line indicates the maximum
25
. .
value from pristine estuaries
~ 20
( .. ~ .. -. . :.
.3:§:
0
~
15
0
Z
0
0
0 0
r:i· ....
:§:
0
:§: 10
'."
«
..
. .
\ 0 ",'
5
0
0
0
0
50
100
150
200
250
300
TOTAL SUSPENDED MAnER (m g 1 - 1 )
Like phosphate, nitrate and nitrite, ammonium concentrations are higher in samples from Sao Gon<;:alo Channel but the influence of this input is not observed at stations further along the longitudinal estuarine axis (i.e., salinity gradient) due to dilution from the greater input from the Northern part of Patos Lagoon.
Ammonium concentrations were higher in shallow waters due to mainly by two
factors:
i. proximity of anthropogenic inputs, and
ii. resuspension of sediments rich in anthropogenic organic matter.
Figure 4.7 distinguishes these two features.
4.3.6
Silicate
The input from Patos Lagoon had an average silicate concentration of 175 jlm, similar
to that reported by Meybeck (1981) for the average discharge of 62% of the total world
runoff. Although there is some variability in silicate concentrations along the salinity
gradient, it generally decreases seaward in a conservative manner, except for the cruises
dominated by the freshwater end-member (cruises 4 and 5) (Fig. 4.8).
In Patos Lagoon Estuary, diatoms are an important component of suspended matter (Hartmann 1988), suggesting dissolved silicate removal in the estuary. The silicate
inputs from Patos Lagoon and Sao Gon<;:alo Channel appear to supply the uptake by
phytoplankton with no apparent significant depletion.
Officer and Ryther (1980) presented some arguments that silicate is often the controlling nutrient in shifting production from diatoms to a flagellates. In Patos Lagoon
Estuary silicate never appears to be limiting, thus providing favourable conditions for
diatom production. Diatoms, which provide the major food source for zooplankton
Luis Felipe Niencheski . Maria da Gra~a Baumgarten· Gilberto Fillmann . Herbert L. Windom
Fig. 4.7. Ammonium concen35
trations plotted against total
(~~:~ . . :.
suspended matter. The points
30
inside the circles are the result
of the strong south winds. The
line indicates the maximum
25
. .
value from pristine estuaries
~ 20
( .. ~ .. -. . :.
.3:§:
0
~
15
0
Z
0
0
0 0
r:i· ....
:§:
0
:§: 10
'."
«
..
. .
\ 0 ",'
5
0
0
0
0
50
100
150
200
250
300
TOTAL SUSPENDED MAnER (m g 1 - 1 )
Like phosphate, nitrate and nitrite, ammonium concentrations are higher in samples from Sao Gon<;:alo Channel but the influence of this input is not observed at stations further along the longitudinal estuarine axis (i.e., salinity gradient) due to dilution from the greater input from the Northern part of Patos Lagoon.
Ammonium concentrations were higher in shallow waters due to mainly by two
factors:
i. proximity of anthropogenic inputs, and
ii. resuspension of sediments rich in anthropogenic organic matter.
Figure 4.7 distinguishes these two features.
4.3.6
Silicate
The input from Patos Lagoon had an average silicate concentration of 175 jlm, similar
to that reported by Meybeck (1981) for the average discharge of 62% of the total world
runoff. Although there is some variability in silicate concentrations along the salinity
gradient, it generally decreases seaward in a conservative manner, except for the cruises
dominated by the freshwater end-member (cruises 4 and 5) (Fig. 4.8).
In Patos Lagoon Estuary, diatoms are an important component of suspended matter (Hartmann 1988), suggesting dissolved silicate removal in the estuary. The silicate
inputs from Patos Lagoon and Sao Gon<;:alo Channel appear to supply the uptake by
phytoplankton with no apparent significant depletion.
Officer and Ryther (1980) presented some arguments that silicate is often the controlling nutrient in shifting production from diatoms to a flagellates. In Patos Lagoon
Estuary silicate never appears to be limiting, thus providing favourable conditions for
diatom production. Diatoms, which provide the major food source for zooplankton