EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Microbial community shift under exposure of dredged sediments from a tropical eutrophic bay

Juliana Nascimento1, Cole Easson2,4, Diogo Jurelevicius3, Jose Lopes4, Edison Bidone1, and Elisamara Sabadini-Santos1
Juliana Nascimento et al.
  • 1Programa de Pós Graduação em Geociêncas (Geoquímica) Universidade Federal Fluminense, Instituto de Química, Geoquímica, Brazil (
  • 2Biology Department, Middle Tennessee State University, Murfreesboro, TN
  • 3Instituto de Microbiologia Professor Paulo de Góes, Centro de Ciências da Saúde, Universidade 12 Federal do Rio de Janeiro, Rio de Janeiro, RJ 21944-570, Brazil.
  • 4Halmos College of Natural Sciences and Oceanography, Nova Southeastern University, Dania 9 Beach, FL 33004, USA

Microbial communities occur in almost every habitat. To evaluate the homeostasis disruption of in situ microbiomes, dredged sediments from Guanabara Bay-Brazil (GB) were mixed with sediments outside the bay (D) in three different proportions (25%, 50% and 75%) which we called GBD25, GBD50 and GBD75. Grain size, TOC and metals -as indicators of complex contamination-; dehydrogenase (DHA) and esterases enzymes (EST) – as indicators of microbial community availability, were determined. Microbial community composition was addressed by amplifying the 16S rRNA gene for DGGE analysis and sequencing using MiSeq platform (Illumina). We applied the Quality Ratio index (QR) to the GB, D and every GBD mixture to integrate geochemical parameters with our microbiome data. QR indicated high environmental risk for GB and every GBD mixture; and low risk for D. The community shifted from aerobic to anaerobic profile, consistent with the characteristics of GB. Sample D was dominated by JTB255 marine benthic group, related to low impacted areas. Milano-WF1B-44 was the most representative of GB, often found in anaerobic and sulfur enriched environments. In GBD, the denitrifying sulfur-oxidizing bacteria, Sulfurovum, was the most representative, typically found in suboxic or anoxic niches. The canonical correspondence analysis was able to explain 60% of the community composition variation and exhibit the decrease of environmental quality as the contamination increases. Physiological and taxonomic shifts of the microbial assemblage in sediments was inferred by QR, which was suitable to determinate sediment risk. The study produced sufficient information to improve dredging plan and management.

How to cite: Nascimento, J., Easson, C., Jurelevicius, D., Lopes, J., Bidone, E., and Sabadini-Santos, E.: Microbial community shift under exposure of dredged sediments from a tropical eutrophic bay, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-11893,, 2020