Results

Disaggregated particle sizes of suspended sediment in upper Chesapeake Bay were very fine, consisting of either clays or fine silts (Table 10.1). The four pumped samples listed in Table 10.1 were all collected from just above the bottom at anchor during two of the seasonal cruises in 2002. No data are available from the October cruise because insufficient material was collected to run a standard gravimetric analysis. Slightly more coarse material (d75 = 16 xm) appears to have been resuspended under strong tidal forcing, but over the weakest flood tide sampled, only clay particles smaller than 1 ¡m were in suspension. There were few apparent seasonal differences in disaggregated suspended particle size, with greater differences between sequential flood and ebb tides than between May and July.

In contrast to these very fine disaggregated particle size distributions, much of the material in suspension was packaged in large flocs. These particles were often visible to the naked eye in the settling tubes and erosion microcosm, and were even more apparent in the magnified video images from the VISTA (Figure 10.4). The flocs visible in Figure 10.4b, collected approximately 1.5 m above bottom during

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