- Dona Paula, Goa, India.
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| Abstract Submission No. | ABS-2022-05-0173 |
| Title of Abstract | Bacterial communities from the Oxygen Minimum Zones of the Arabian Sea and Bay of Bengal Basins |
| Authors | Samir Damare*, Genevieve Fernandes, Larissa Menezes, Amara Mulla Begum, Ram Murti Meena |
| Organisation | CSIR-National Institute of Oceanography |
| Address | CSIR-National Institute of Oceanography Dona Paula, Panaji, Goa, India Pincode: 403004 Mobile: 9422058520 E-mail: samir@nio.org |
| Country | India |
| Presentation | Oral |
| Abstract | The Indian ocean OMZ which include the Arabian Sea and Bay of Bengal is characterized by O2 concentration <0.1 ml L-1 within a depth ranging from ~100/150 to 1,000 m. Both the basins show a contrasting difference in their biogeochemical cycling due to the fact that Arabian Sea has a lower O2 concentration as compared to Bay of Bengal. Differences in the oxygen levels, effects a change in the living biota in the water column. Culture-dependent techniques alone does not give a holistic account of the bacterial diversity as less than 5% of the bacterial population can be detected using this. The emergence of culture-independent approach has allowed us to assess the diversity in better perspective which can detect rare populations also. In the present study, samples have been collected from the OMZs of both Arabian Sea and Bay of Bengal over 5 years to compare the microbial population present in there. Different culturing techniques along of the modern Next Generation Sequencing approach were employed to describe the diverse microbial communities present. The water samples were collected from the upper interface of OMZ, mid-OMZ and lower interface of OMZ. For culture-independent diversity, DNA were extracted and high-throughput amplicon sequencing of V3/V4 and V6 16S rDNA regions was performed on Illumina HiSeq. A comparison between the two areas showed that Proteobacteria were the largest contributors in the both the basins, but were higher in AS (89.30%) than BOB (67.10%). Gamma sulphur oxidisers (GSO) SUP05 reported to have the genetic potential to oxidize reduced sulphur in oxygen minimum zones having a role in cryptic sulphur cycle- higher in BOB (1.80%) than AS (0.70%). Pelagibacteraceae, encompassing quarter-half of the prokaryotic cells in the ocean was higher in BOB (26.00%) than AS (20.50%). SAR406 belonging to the Marine Group A (MGA) uncultivated phylum of bacteria reported in carrying out dissimilatory sulfur oxidation was found to be second most abundant phylum, higher in BOB (36.00%) than AS (21.20%). Phylum Planctomycetes involved in anaerobic oxidation of ammonium to nitrite or nitrate to yield N2, contributing to nitrogen loss in oxygen-deļ¬cient systems was higher in AS (4.90%) than BOB (1.10%). To understand the functional differences, generic level comparison is best suited, but the main problem with this approach was that high percent of organisms were left as unclassified and not falling within defined genera. |