Trophic status of Danube River and its tributaries using chlorophyll a as an indicator

Abstract

The study aims to assess the trophic state of Danube River and the main tributaries in the Southern part of Romania through chlorophyll „a” (Chl a) dynamics during 2015. The samples were collected with a seasonally frequency. Several environmental variables such as water temperature, pH, salinity, dissolved oxygen, nutrients were considered. In addition, the qualitative analysis of phytoplankton community was performed. The integrative approach, which included both in-situ and laboratory analysis, highlighted positive correlation between abiotic and biotic parameters. The chlorophyll „a” dynamics showed a close dependence with the sampling sites characteristics, the point sources of pollution, phytoplankton community and specific changes of chemical parameters.