Orbulina universa d'Orbigny, 1839

Orbulina universa (Fig. 35) is one of the most widely distributed species in planktic foraminifera. Except in a few samples it does not exceed 3-4 % in relative abundance. As expected from the wide geographic distribution there is hardly any relation of relative abundance with the analysed physical parameters. Only sea surface salinity seems to relate with the relative abundance, with a maximum between 35.5 - 36 psu for summer and winter salinities. The species shows a very pronounced maximum in relative abundances (>4 %) where summer salinities are 35.5 psu. The three highest relative abundance values behave as "outliers" in most plots and would be suspicuous of error if the relation with sea surface salinity would be unknown. The number of 8 samples with more than 3-4 % O. universa is not big enough to analyse the width of the salinity optimum. Further research, however, may be justified to calibrate this species as an excellent indicator of average marine salinities.

42 kB

Figure 35: Orbulina universa d'Orbigny, 1839. Plots of relative abundance vs. selected physical parameters and latitude. For preferences in numeric form see appendix.

back to species list
access to all figures and tables