The chemistry, mineralogy, and rates of transport of sediments in the ...

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of PZ`a , "a , and "a was transported in a similar form (i .e . particulate
organic matter) . However, some of the mass of PCa is transported as inorganic
carbon in calcite and dolomite (Table 8) and some of the PP a is
likely in an inorganic form .
2
The previous discussion is based upon the assumption that relationships
between discharge, annual suspended sediment loads and chemical
components of suspended sediments would be useful in establishing baseline
data for the region, and to assist in the perception of changes in these
parameters caused by natural events and technological disturbance of the
terrain. We also suggested that transport rates of most parameters previously
discussed (Tables 3, ;8, 9, 10 and 14) in units of mass per unit
watershed area per year can be extrapolated to unsampled watersheds of
similar geography, climate, and vegetation . For example, we estimated the
annual mass of SS, PC, PN, and PP supplied to the Mackenzie Delta and Beaufort
Sea by the Mackenzie and Peel Rivers from our data and by extrapolation
(Table 15) . We applied the rates of transport (per unit watershed area) of
the Arctic Red River to the western tr-*1tary area of the Mackenzie north
of Norman Wells, where we have no useful, seasonal data . This assumes that
the Carcajou, Mountain, Hume, Ramparts, and Ontaratue Rivers have SS,,
PC w , PNw , and PPw similar to the Arctic Red River, and that small tributaries
have a negligible contribution . The eastern watershed of the
Mackenzie north of Norman Wells was not sampled in detail, but its small
contribution to the total Mackenzie load was estimated from average transport
rates of SS W , PCw , PNw and PP, from the Willowlake River . We believe
that this approach (or refinements based on more detailed and longer records
of data) is better than the use of the Universal Soil Loss Equation (Howard,
1974) . Table 15 indicates that the mole ratio N/P of sediments_ supplied to
the Mackenzie Delta and Beaufort Sea is very low (5 .6), which may result
from some fraction of PPa being in inorganic form . The mole ratio C/P is
close to expected values for living organic matter, however . The average
sedimentation rate for the Mackenzie Delta and adjacent Beaufort Sea given
in Table 15 is likely somewhat misleading, since much of the annual supply
of sediments moves through the Mackenzie Delta to be deposited in restricted
areas of sediment accumulation in Kugmallit Bay, Shallow Bay, and shallow
areas in the Beaufort Sea less than 80 km from the northern edge of the
terrestrial portion of the Delta . However, sediment of the composition
given in Table 15 is within 5% of C, N, and P determined in samples of
sediments from the Beaufort Sea, Kugmallit Bay, and turbid northern Delta
lakes (see Campbell et at ., 1975, for C, N, P, data for sediments from
stations BS24, BS26, BS15, KU4, KU5, Lake 1, Lake 3 . To convert sedimentation
rate in Table 15 to . concentration (in moles/g dry wt . sediment),
divide moles of C, N, and p 1-2 yr-1 by 3,800 g .SS m-2yr-1 ) .
The multiple linear regression analyses .(Table 13) .clearly identify
watershed area, relief, and forest cover as dominant controlling factors
on the rates of transport of . sediments and particulate nutrients for the
watersheds studied . With increasing Ad, SSa and SSW increased . The great
importance of watershed area seems obvious, since all transport rates discussed
here are a close function of the magnitude of annual discharge,