Abundance of respiring bacterial cells in the marine beaches as a potential bioindicator of the intensity of organic matter decomposition

Abstract

The present study was carried out on the marine beaches located on the Polish part of the Baltic Sea coast which differed in the level of anthropopressure. This paper aimed to determine the abundance of respiring bacterial cells and total bacterial number to provide reliable information on the seasonal dynamics of these organisms and their spatial distribution in the studied beaches. The results of our study showed that on the beach which was heavily influenced by human pressure, the percentage of respiring bacteriopsammon cells compared to the total bacterial number was almost twofold lower than that in the beach characterized by a negligible level of anthropopressure. Our study also showed that the abundance of respiring bacteria differed along the horizontal profile in studied beaches. The maximum abundance of these bacteria was noted in dry zones, i.e., in the middle part of the beach and the dune. In the vertical profile of the studied beaches, the highest number of the studied bacterial group was determined in the surface sand layer. The number of respiring bacteria showed a seasonal variation as well. The assessment of respiring bacteria might be an potential indicator of the level of organic matter decomposition on the beach.