Earth, Atmosphere & Environment Sciences
Title : | Studies on impact and response of ecologically important bacteria towards environmental stressors of Bhitarkanika Mangrove ecosystem, Odisha |
Area of research : | Earth, Atmosphere & Environment Sciences |
Focus area : | Ocean science |
Principal Investigator : | Dr. Surajit Das, Associate Professor, Department of Life Science, National Institute of Technology, Rourkela, Odisha- 769 008, Odisha |
Timeline Start Year : | 2019 |
Timeline End Year : | 2022 |
Details
Executive Summary : | Mangroves found in most tropical and subtropical marine regions in the intertidal zones
of river deltas hold a greater diversity of flora, fauna, and microorganisms. Being associated with
the marine ecosystem, they deal with the dynamic temperature, tidal regime, pH, salinity and
heavy metals. Among the microorganisms present in these environments, bacteria respond
quickly to this dynamic conditions at both phenotypic and genotypic levels. The bacterial
community forms the biofilm in such fluctuating environmental conditions for its growth and
survivability. The biofilm formation ability of bacteria helps them to adhere to every substrate
and operate various nutrient cycling processes. However, fluctuating environmental parameters
affect their efficiency in operating various biogeochemical cycles. The current research focuses
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on the effect of various stressors on the mangrove bacteria and thereby understanding their role
in the regulation of ecosystem-level processes. In this study, a comparative analysis was done
between Bacillus stercoris GST-03 (a gram-positive bacterium) and Pseudomonas balerica
DST-02 (a gram-negative bacterium). B. stercoris GST-03 was found to be stress tolerating
bacterium showing tolerance towards lower pH. In contrast, P. balerica DST-02 was found to be
a good biofilm former. B. stercoris GST-03 shows cellulose degradation potential, which
indicates it will play a crucial role in cellulose degradation in the mangrove ecosystem. In
addition, B. stercoris GST-03 shows higher tolerance to temperature, salinity, heavy metals and
UV compared to P. balerica DST-02. The identification of pslB and tasA in P. balerica DST-02
and B. stercoris GST-03, respectively, validates their biofilm-forming ability. The presence of
genes, celA and celB validates the cellulose degradation ability of B. stercoris GST-03. The
fluctuation in the environmental parameters leads to the production of ROS in both strains. ROS
production was found to be minimum during the optimum growth conditions. Further, the
oxidative stress-mediated DNA damage and repair mechanism were studied. The production of
DNA damage products and antioxidants co-occurs. The condition at which the correlation
between them imbalances leads to irreparable DNA damage in bacteria. The resulting output of
the expression analysis of genes involved in the NER and SOS response pathway depicted the
DNA damage at pH 9, and Pb concentration 1000 might be irreparable in B. stercoris GST-03. In
contrast, DNA damage at pH 4 and 9, 1000 ppm of Pb and 200 ppm of Cd might be irreparable
in P. balerica DST-02. The microcosm study revealed that B. stercoris GST-03 shows more
tolerance and produces dense biofilm in the stress condition predicted for the year 2100
compared to P. balerica DST-02. The present work demonstrates the effect of various stressors
on the mangrove bacteria that will help to understand the fate of the mangrove bacteria in future
climate change scenarios. |
Co-PI: | Dr. R. Jayabalan, Assistant Professor, National Institute of Technology, Rourkela, Odisha |
Total Budget (INR): | 45,16,400 |
Outcome/Output: | The findings of the present studies will help us in understanding the effect of
environmental and climatic stressors on the physiological properties of mangrove bacteria and overall biogeochemical cycles affecting the overall ecosystem balance. These findings will help in developing a future projection about the fate of mangrove bacteria in the fluctuating environment in the context to metal pollution, ocean acidification associated with drastic change of temperature and UVR radiation. The overwhelming consensus ofthe present day is the hazardous effects of global warming simulations like ocean acidification, temperature alterations and deleterious UVR, on marine ecosystems. While mangrove bacteria being the key players of the biogeochemical cycles of the world are under greatest threat due to such environmental stressors. The preservation of their genome integrity is thus an important environmental constraint. Keeping the future perspectives of such environmental hazards |
Organizations involved