Abstract
The morphologic variations of six species of planktonic foraminifera were quantified using image analysis, closed-form Fourier analysis and subsequent EXTENDED CABFAC and QMODEL factor analyses. Within a species, morphologic fluctuations around a harmonic mean proved to be the result of identifiable groups or morphotypes. Six morphotypes of Globigerinoides ruber, 3 morphotypes of G. sacculifer, 4 morphotypes of G. menardii, 4 morphotypes of Neogloboquadrina dutertrei, and 3 morphotypes of Globorotalia tumida were quantitatively defined in 16 core tops from around the tropics. The percentages of morphotypes within a species were found to differ spatially, but often was not related to common environmental parameters, such as temperature and salinity. However, an additional study determined that Orbulina universa shows the most phenotypic variability in the marginal marine setting of the Cariaco Trench and that this may be a function of the high nutrient levels of the area.Stable isotopes of morphotypes were determined for two species, Globigerinoides ruber and G. sacculifer: G. ruber morphotypes showed distinct isotopic differences, while G. sacculifer morphotypes showed more scatter in the values. Morphologic and isotopic data suggest that G. ruber morphotypes may be genetically distinct, although genetic information is not available for planktonic foraminifera at the present.A possible source of genetic information, the individual proteins for the shell matrix of six species of core top planktonic foraminifera, was extracted for the first time. A number of different techniques were employed in the isolation and characterization of the individual proteins, including one and two dimensional gel electrophoresis, radioiodination and electroelution of the proteins, HPLC gel filtration and reverse phase protein separations, and amino acid analysis. Amino acid analyses of the proteins indicated possible species specific protein signals. Individual proteins from spinose species showed significantly higher aspartic acid and lower alanine percentages than non-spinose species. The foraminiferal proteins also showed similarities to collagen and elastin and thus, may have considerable influence in the process of chamber development and calcification. Scanning electron microscopy showed that the Primary Organic Membrane of the shell, which contains the proteins, is preserved for at least 300,000 years under the deep-sea conditions of the cores.