Distribution and abundance of microflora in sandy beaches on the southern coast of the Baltic Sea

Abstract

The abundance of actinomycetes, filamentous fungi and yeasts in the marine epipsammon habitat and their spatial distribution were studied with conventional plating techniques in two marine beaches (Ustka and Czołpino, southern Baltic Sea) which are characterized by different anthropic pressure levels. Actinomycetes constituted the predominant group of studied microorganisms, while the least numerous were yeasts in the sand of both studied beaches. On both of the beaches researched in this study, the amounts of accumulated actinomycetales, fungi and yeasts were similar. When analyzing the distribution of the microflora along the horizontal beach profiles we found significant differences. In the sand collected along the profile perpendicular to the shoreline in Ustka and Czołpino beaches, the highest numbers of actinomycetes, filamentous fungi and yeasts were noted in the samples from the dune and the lowest in those from the subtidal zone and waterline. Generally, higher numbers of studied microorganisms were observed in the surface * Corresponding author e-mail: pperlinski@apsl.edu.pl than in the subsurface sand layer. The occurrence of actinomycetes, filamentous fungi and yeasts showed considerable seasonal variation.

Taxonomic and functional analyses reveal existence of virulence and antibiotic resistance genes in beach sand bacterial populations

“…They are different in that the Chao1 estimator gives greater weight to low abundance species (species with less than 10 individuals in a sample), while the ACE estimator gives greater weight to species sample coverage (species with more than 10 individuals in a sample) (Kim et al 2017 ). In this study, however, both estimators still showed high bacterial species richness in all beach sand samples, as also observed in other beach sand samples (Mudryk et al 2013 ; Romão et al 2017 ). This confirms earlier findings that beach sands are microhabitats teaming with microbial life (Sabino et al 2014 ; Whitman et al 2014 ; Solo-Gabriele et al 2015 ).…”

“…However, sandy beaches are not just piles of sand; they harbour their own micro-ecosystems. They receive large inputs of organic matter supplied by the seawater, consisting of phytobenthos assimilates, and products washed and leached out from seaweeds, animal faeces, and remains of plants and animals (Mudryk et al 2013 ). This creates optimal conditions for the growth of a high population of organisms such as small invertebrates, bacteria, actinomycetes, fungi, yeast, virus, algae, and diatoms (Zakaria et al 2011 ; Whitman et al 2014 ; Di Piazza et al 2017 ), making beach sand a potential reservoir for aetiological agents of disease (Solo-Gabriele et al 2015 ).…”