Microbial activity in surface sediments of Chacopata-Bocaripo lagoon axis, Sucre State, Venezuela

• The first study on marine sediments to report microbial activity in Sucre, Venezuela.
• Changes in marine sediments can be evaluated by microbial and biochemical parameters.
• Microbial and biochemical parameters studied in Ch-BLA exhibited marked seasonality.

The aim of this work was to evaluate the microbial activity of the surface sediments (0–10 cm) of the Chacopata-Bocaripo lagoon axis (Ch-BLA) through microbiological parameters: microbial biomass (Cmic) dehydrogenase activity (DHS), fluorescein diacetate hydrolysis (HFDA), arginine ammonification (AA) and biochemical parameters: phosphatase (PHa) and urease (URa) activity. They were determined during transition (July 2010) and upwelling (March 2011) periods. Total organic carbon (TOC) did not vary significantly (p ⩾ 0.05) between climatic periods. All the parameters studied were higher in upwelling season: Cmic (191.79 mg Cmic kg−1), DHS (228.70 μg TFF g−1 24 h−1), HFDA (204.09 μg fluorescein g−1 24 h−1), AA (13.09 μg NH4-N g−1 h−1), PHa (132.31 μg pNF g−1 h−1), URa (12.90 μg NH4-N g−1 h−1). They appear to be controlled by the availability and quality of nutrients in each climatic period, and were useful tools for evaluating changes in microbial activity in marine sediments.