Microbial enzymatic activity and its relation to organic matter abundance on sheltered and exposed beaches on the Polish coast

The activity of lipase, aminopeptidase, α-glucosidase, β-glucosidase was correlated and assessed according to an abundance of organic matter and total forms of nutrients in beach sediments characterized by different strength of anthropopressure and degree of sheltering. 76% of the data variance was explained by six factors identified by the use of principal component analysis: (1) anthropogenic rich in N, (2) microbial enzymatic activity, (3) labile organic matter, (4) bacterial growth, (5) anthropogenic rich in P and (6) hydrolytic. Differences in secondary bacterial production according to the distance from the water line, vertical cores and seasonality are limited by the accessibility of biochemical compounds (lipids, proteins, carbohydrates, total organic carbon), total phosphorus and nitrogen. Sediments collected in exposed beaches were not as rich in organic matter as these collected in sheltered ones due to the impact of sea waves of higher energy and backward current facilitating cleaning. The highest microbial enzymatic activity was observed in the beach infilled prior to the tourist season with well-aerated sand mined from the main harbor canal. Microorganisms induce α-glucosidase synthesis to decompose hardly assimilable COM during deficit of easily assimilable PRT and CHO. The lack of easily assimilable matter activates stronger hydrolytic activity in lower layers of core sediments.