Pivovarov et al.: Dissolved Oxygen. Silicon. Phosphorous and Suspended Matter Concentrations
5000
4000
~ 3000
c
o
~ 2000
1000
o
winter water
water on ice
i
n h , h
17 19 21
23
25 27 29
31
MAY
t=J suspended particulate matter (SPM)
_ dissolved inorganic silicon
r high discharge water
~ ~ ~
3
5
7
9
11 13
JUNE
f257
35
30
25 ~
E
20 ~
::2;
15 fu
10
5
Figure 5: Silicon and suspended matter concentration in the Lena river near research station "Lena-Nordenskj¢ld"
(Bykovskaya distributary) in May-June 1996.
maximum concentrations of more than 70 mg/l (Station 8). This suggest that erosion of seafloor
sediment does not contribute to the high SPM concentrations above the pycnocline.
Another process affecting the dispersion of riverine SPM was observed during the third
survey. Frazil ice formed at the contact between the freshwater and the saline water masses
(Golovin et aI., this volume). The rising frazil ice formed large conglomerates of ice platelets
under the fast ice. Particulate matter concentrations above 1000 mg/kg in the ice suggest that
frazil ice formation is an effective SPM scavenging mechanism during the river breakup
(Golovin et aI., this volume).
Discussion
Spreading of river water deduced from silicon distribution in the Laptev Sea
The dissolved silicon concentration in Siberian rivers is high, compared to the surface layer of
the Arctic Basin. Thus, the distribution of silicon can be used as a tracer for the identification of
river water in Arctic shelf seas (Rusanov, 1974; Rusanov and Ivanov, 1978; Ivanov et aI.,
1984). The 250 Ilg/l isoline is assumed to be the boundary of water masses influenced strongly
by freshwater input and marine water masses (Rusanov et aI., 1979; Buynevich et aI., 1980).
Figure 8 describes the general silicon distribution pattern (summer and winter) in surface
water of the Laptev Sea. The mean silicon distribution based on data of II oceanographic
surveys during summer (August-September) is illustrated in Figure 8b. The influence of river
water at this time of the year is predominant in the eastern Laptev Sea. In the western region,
the influence of water masses with low silicon content from the Arctic Ocean is predominant
and only the coastal regions are affected by river runoff. The winter (March-May) distribution
(5 m) is shown in Figure 8B. This spatial distribution is based on data from 5 oceanographic
surveys carried out during airborne expeditions from 1980 to 1986. Comparing the two
distribution patterns, it becomes evident that the spatial distribution of freshwater in the upper
water layer within the Laptev Sea remains approximately the same during summer and winter.
However, silicon concentration during winter is twice as high as during summer.
5000
4000
~ 3000
c
o
~ 2000
1000
o
winter water
water on ice
i
n h , h
17 19 21
23
25 27 29
31
MAY
t=J suspended particulate matter (SPM)
_ dissolved inorganic silicon
r high discharge water
~ ~ ~
3
5
7
9
11 13
JUNE
f257
35
30
25 ~
E
20 ~
::2;
15 fu
10
5
Figure 5: Silicon and suspended matter concentration in the Lena river near research station "Lena-Nordenskj¢ld"
(Bykovskaya distributary) in May-June 1996.
maximum concentrations of more than 70 mg/l (Station 8). This suggest that erosion of seafloor
sediment does not contribute to the high SPM concentrations above the pycnocline.
Another process affecting the dispersion of riverine SPM was observed during the third
survey. Frazil ice formed at the contact between the freshwater and the saline water masses
(Golovin et aI., this volume). The rising frazil ice formed large conglomerates of ice platelets
under the fast ice. Particulate matter concentrations above 1000 mg/kg in the ice suggest that
frazil ice formation is an effective SPM scavenging mechanism during the river breakup
(Golovin et aI., this volume).
Discussion
Spreading of river water deduced from silicon distribution in the Laptev Sea
The dissolved silicon concentration in Siberian rivers is high, compared to the surface layer of
the Arctic Basin. Thus, the distribution of silicon can be used as a tracer for the identification of
river water in Arctic shelf seas (Rusanov, 1974; Rusanov and Ivanov, 1978; Ivanov et aI.,
1984). The 250 Ilg/l isoline is assumed to be the boundary of water masses influenced strongly
by freshwater input and marine water masses (Rusanov et aI., 1979; Buynevich et aI., 1980).
Figure 8 describes the general silicon distribution pattern (summer and winter) in surface
water of the Laptev Sea. The mean silicon distribution based on data of II oceanographic
surveys during summer (August-September) is illustrated in Figure 8b. The influence of river
water at this time of the year is predominant in the eastern Laptev Sea. In the western region,
the influence of water masses with low silicon content from the Arctic Ocean is predominant
and only the coastal regions are affected by river runoff. The winter (March-May) distribution
(5 m) is shown in Figure 8B. This spatial distribution is based on data from 5 oceanographic
surveys carried out during airborne expeditions from 1980 to 1986. Comparing the two
distribution patterns, it becomes evident that the spatial distribution of freshwater in the upper
water layer within the Laptev Sea remains approximately the same during summer and winter.
However, silicon concentration during winter is twice as high as during summer.