Figure 12. The summary of abundance in different planktonic foraminifers assemblages (Gulf Stream, subtropical gyre, gyre margin, and northern globorotaliid species) with the occurrence of low-oxygen benthic foraminifers and pyrite tubes plotted as a time series. The second column shows inferred hydrographic conditions of water masses, Gulf Stream strength, and sea-surface temperature derived from the changes of these planktonic assemblages. The third column summarizes the paleoceanographic events in Hole 997A and at other sites in the North Atlantic Ocean.