Insights into Late Quaternary calcareous nannoplankton assemblages under the theory of the statistical analysis for compositional data

The investigation of changes in abundance of calcareous nannofossil associations is fundamental for palaeoclimatic and palaeoceanographic reconstructions. In general, since the number of recognised species is high, the numerical and graphical treatments of the data play an important role to validate hypotheses about the influence of physico-chemical factors on the quality of past environments, as reflected by changes in abundance. Moreover, the application of multivariate procedures may be useful for improving interpretation of the overall data structure. Calcareous nannofossil associations analysed in this work are related to core GNS84-C106 collected in the Gulf of Salerno (Campania, southern Italy) under a national interdisciplinary research programme aimed at recognising the impact of natural events on biological communities during the last 20 kyr. Biplot analysis of compositional data was applied to indicate the presence of subcompositions or, in other words, to identify strong relationships among a limited number of species that can be interpreted from a palaeoenvironmental point of view.