PRINCIPAL COMPONENT ANALYSIS OF THE PHYTOPLANKTON INTERACTIONS WITH THE ENVIRONMENTAL FACTORS IN TWO RESERVOIRS IN BULGARIA

摘要

In the present study, we have analyzed the connection between the main environmental parameters and the quantitative characteristics of the phytoplankton communities in two economically significant Bulgarian reservoirs (Kardzhali and Dospat) for a one-year period (April 2011 - April 2012). The aim of this study was to identify the key environmental factors influencing the phytoplankton development, by implementation PCA analysis based on the Pearson correlation matrix. The conducted PCA identified 5principal components, which explained 83.64% and 79.91% of the total variance for both reservoirs respectively. The data analysis indicates, that physical parameters, such as water transparency (Sd), electrical conductivity (Cond.), pH, concentration andsaturation of the dissolved oxygen (02, 02%), and the different forms of nitrogen and phosphorus (N03-N, TN, P04-P, TP, CODMn), as well as a total count of heterotrophic bacteria (TVC) have considerable impact on the phytoplankton dynamics in Kardzhalireservoir. Similar dependences between environmental factors and phytoplankton community, with the exception of 02 and 02%, were established for Dospat reservoir. The obtained results demonstrate the applicability of the multivariate statistical analysismethods for the determination of the main factor influencing the quantitative, spatial and seasonal phytoplankton development in heavily modified water bodies.