Influence of the mineralogical composition on microbial activities in marine sediments: an experimental approach

Abstract

We investigated the influence of the mineralogical composition of marine sediments on bacterial activity in experimental microcosms. Calcite and quartz were added to natural marine sediments and microbial response in terms of total bacterial abundance and biomass, β-D-glucosidase exo-enzymatic activity and bacterial incorporation of a radio-labelled (³H-leucine) substrate were investigated for a period of one month. We report here that after 15 days the mineralogical composition of the sediment (calcite vs. quartz) had an impact on bacterial abundance and activity (reduced for ca 15% and 56%, respectively). However, such impact was mitigated or even disappeared in high organic nutrient conditions.

Keywords:

• Bacterial activity
• Mineralogical composition
• Sediment

Acknowledgements

The authors thank Dr. A. Dell'Anno for precious and stimulating discussions on an early draft of the manuscript and to Prof. G. Bavestrello for promoting and stimulating this study and for providing mineral substrates. Dr. L. Gobbi and Prof. G. Moriconi are acknowledged for SEM and X-ray analyses of the sediments.