Actual Sédimentation on the Antarctic Continental Shelf...
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been demonstrated. This is very clear in the waters off the AASW with high
concentrations of suspended matter above the thermocline and low values
immediately beneath them [8].
We hâve defined a sector of the RIS where the suspended matter concentrations are higher and where the diffusion fluxes are spreading northwards; this
spreading is in the surface and in the water close to the bottom, and the suspended matter has different concentration and dimensional characteristics. The concentrations of SPM are lower in the intermediate waters which are also characterized by particles with small dimensions (30 pm); the lowest values in concentration and in dimension are found in the intermediate waters coming from the open
sea. There is a general influence of the RIS on the shelf waters and its higher limit
seems to be situated around 77 °S. This latitude is the limit for the diffusion of
SPM conveyed by AASW and WMCO too.
The SPM of the internai sector (south of 77° of latitude) spreads in surface
waters northwards and in north-west direction, while, near the bottom, it seems
essentially northwards. In the external sector, the diffusion seems to be southwards in the intermediate waters, while the situation seems to be different in the
superficial water with a north-westwards diffusion. These results are reported in
a sédimentation model [12] illustrated in Fig. 9 with the percentage values of
SPM. We plotted ail the results of suspended matter concentration found in two
sectors (south and north of the 77°). Superficial and subsuperficial waters (0-100
m) are always the richest in particulate matter and their values are reported to
100% of suspended matter; the other calculated values for the intermediate
waters, for the waters between 400 and 500 m and for the bottom water are taken
as base 100.
Close to the RIS the différence in suspended matter between the surface and
intermediate waters is in the order of 57%, and the suspended matter lost at a
depth of 250 m is conveyed laterally and diffuses, probably towards the fourth
quadrant. The situation in the low part of the column of water is different, with an
increase of 14% at 450 m and of a further 14% at the bottom. This progressive
increase in concentration can only be linked to latéral contributions of suspendFig. 9. Hypothesis of sédimentation in proximity of the RIS and at the edge of the continental shelf (% values of TPM)
205
been demonstrated. This is very clear in the waters off the AASW with high
concentrations of suspended matter above the thermocline and low values
immediately beneath them [8].
We hâve defined a sector of the RIS where the suspended matter concentrations are higher and where the diffusion fluxes are spreading northwards; this
spreading is in the surface and in the water close to the bottom, and the suspended matter has different concentration and dimensional characteristics. The concentrations of SPM are lower in the intermediate waters which are also characterized by particles with small dimensions (30 pm); the lowest values in concentration and in dimension are found in the intermediate waters coming from the open
sea. There is a general influence of the RIS on the shelf waters and its higher limit
seems to be situated around 77 °S. This latitude is the limit for the diffusion of
SPM conveyed by AASW and WMCO too.
The SPM of the internai sector (south of 77° of latitude) spreads in surface
waters northwards and in north-west direction, while, near the bottom, it seems
essentially northwards. In the external sector, the diffusion seems to be southwards in the intermediate waters, while the situation seems to be different in the
superficial water with a north-westwards diffusion. These results are reported in
a sédimentation model [12] illustrated in Fig. 9 with the percentage values of
SPM. We plotted ail the results of suspended matter concentration found in two
sectors (south and north of the 77°). Superficial and subsuperficial waters (0-100
m) are always the richest in particulate matter and their values are reported to
100% of suspended matter; the other calculated values for the intermediate
waters, for the waters between 400 and 500 m and for the bottom water are taken
as base 100.
Close to the RIS the différence in suspended matter between the surface and
intermediate waters is in the order of 57%, and the suspended matter lost at a
depth of 250 m is conveyed laterally and diffuses, probably towards the fourth
quadrant. The situation in the low part of the column of water is different, with an
increase of 14% at 450 m and of a further 14% at the bottom. This progressive
increase in concentration can only be linked to latéral contributions of suspendFig. 9. Hypothesis of sédimentation in proximity of the RIS and at the edge of the continental shelf (% values of TPM)