SUMMARY

The diatoms present in the material from Site 1063 convey a complicated history for this site. The dominant species in the assemblage changes many times over the four cores examined. Assemblage dominance noted in the sieved samples varies between three groups: (1) E. rex, (2) Coscinodiscus radiatus and A. nodulifer, and (3) Thalassionema spp., Thalassiothrix spp., and Bacteriastrium spines. Species associated with littoral and coastal environments exhibit a greater abundance in the lower samples than those higher up. The species diversity of the entire assemblage does not change between intervals with more and less abundant diatoms, but the individual species do not experience uniform increases and decreases. Some few species were observed to either disappear from the sediment record or exist for a limited time only. Differences of these sorts would indicate some changes in currents and/or water masses between different depth intervals.

Whereas there are many patterns evident through comparing the presence and abundance of the diatom species observed in this study, data from other cores in the same region and in similar settings needs to be added before definite conclusions can be drawn.

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