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| Author(s): |
Paula Carpintero de Moraes
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Instituto Oceanográfico (IO/DIDC) |
| Defense date: | 2012-12-19 |
| Examining board members: |
Paulo Yukio Gomes Sumida;
Michel Michaelovitch de Mahiques;
Cristina Rossi Nakayama;
Vivian Helena Pellizari
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| Advisor: | Paulo Yukio Gomes Sumida |
| Abstract | |
The present study aimed to investigate the effects of sediment resuspension and organic enrichment by different microalgae on the sedimentary microbial community structure. We run two separate laboratory experiments (Nov-Dec/2009 and Apr-May/2011) to simulate resuspension conditions and pulses of primary productivity observed in the field, and analyze how these events affect the microbial community. Both experiments were maintained for a total of 30 days following treatment when samples were taken for sedimentary analysis, prokaryotic density and bacterial community analyses at six different sampling times. The sediment surface layer was studied in more detail, and showed that both the input of algal material and resuspension are responsible for significant changes in density, metabolism and bacterial community composition. Also, the arrival of different types of algae to the sediment (phytoflagellates and diatoms) led to different responses in both density and diversity of sedimentary microorganisms. The vertical structure of microorganisms in the sediment column was also studied. The arrival of algal material in the sediment did not show important changes in community structure of the deeper sedimentary layers. The stability created by the experimental environment seems to increase both the density and diversity of microbes in the middle layer of sediment in both treatments and control. On the other hand resuspension seems to influence more effectively the distribution of microorganisms in the sedimentary column due to sediment mixing and changes in redox conditions of different layers. In conclusion, both the arrival of food on the sediment and resuspension events is responsible for important changes in the coastal sediment microbial communities. (AU) | |
| FAPESP's process: | 08/08244-8 - Ressuspension and organic enrichment efects in the biogeoquimical process and microbial community of sediments |
| Grantee: | Paula Carpintero de Moraes |
| Support Opportunities: | Scholarships in Brazil - Doctorate |