109^ 



In the additional Royal River cores, thecamoebians varied from 7% to 17% in the 

 samples (Figure 4-31 A). In composition, the microfossils in the cores were comparable to 

 RR-26 located in the upper middle reach, with the exception of mudflat calcareous 

 specimens. The percentage of thecamoebians in the additional cores was close to that in 

 RR-26 and increased with the proximity of the core location to the upper river region. 



Marsh foraminifera were predominant in all samples, however, many of them had 

 poorly preserved shells. Mudflat calcareous foraminifera were absent in RR-3F and RR- 

 3M, and composed only a small percentage of RR-5 and RR-6. Shelf calcareous 

 foraminifera were found in RR-6, and shelf agglutinated foraminifera varied from 0.6% to 

 4% in the four cores. One of the shelf agglutinated specimens in RR-6, Martinotiella 

 communis, was not seen in any of the prior samples from the Royal River or at the PDS. 

 The small percentage of shelf agglutinated foraminifera was greater than previously seen in 

 the Royal River cores in which only one had been observed in RR-26. The shelf 

 calcareous foraminifera also had a greater abundance in RR-6 than seen before at RR-18 in 

 the middle region. 



Comparison of formalin and methanol solutions in samples from RR-3 was limited 

 to the preservation of non-calcareous species due to the apparent dissolution of the 

 calcareous fraction. Almost double the number of thecamoebians and a few more shelf 

 agglutinated specimens were counted in the RR-3M (methanol) samples dian found in the 

 RR-3F (formalin) samples (Figure 4-31B). The microfossil content in the three additional 

 cores had a greater density than in the Royal River cores processed in 1995, which had 

 been preserved in methanol, possibly reflecting the difference in preservation solution 

 used. However, because the formalin and methanol preserved solutions were similar in the 

 numbers per tray, the greater density probably was representative of a larger 

 microorganism community in this transition area between the upper and middle regions. 



The additional Royal River cores were classified with respect to the actual dredging 

 plan as follows: RR-6, pseudo-UDM (phase 1); RR-5, pseudo-UDM (phase 2) near the 

 border with CDM; and RR-3, CDM (Figure 2-10). The cores did not have distinct enough 

 characteristics to classify them as separate regions, therefore, the later portion dredged for 

 CDM shared some characteristics with the pseudo-UDM. 



The microfossil abundance and total number (the density was not calculated for the 

 additional cores) of the additional cores were comparable to the PDS grab and core 

 samples. Although the mudflat calcareous specimens were reduced in the additional cores, 

 the pseudo-UDM grab and core sample means were more consistent with Cores RR-6 and 

 RR-5 than those previously described for the upper region. The additional cores provided 

 evidence that some of the shelf species in the CDM, pseudo-UDM core, and pseudo-UDM 

 grab samples were probably derived from the areas surrounding Cores RR-3, RR-5, and 

 RR-6 in the Royal River. 



The Portland Disposal Site Capping Demonstration Project, 1995-1997 



