Biodidaktika : Jurnal Biologi dan Pembelajarannya
Vol 21, No 2 (2026)

Bacterial Diversity in Flores Sea Surface Water Revealed by Reanalysis of Public Shotgun Metagenomic Data

Mardalisa Mardalisa (Department of Marine Science, Faculty of Fishery and Marine Science, Universitas Riau)
Nursyirwani Nursyirwani (Department of Marine Science, Faculty of Fishery and Marine Science, Universitas Riau)
Nabila Afifah Azuga (Department of Marine Science, Faculty of Fishery and Marine Science, Universitas Riau)
Lilies Handayani (Department of Statistics, Faculty of Mathematics and Natural Science, Tadulako University, Palu 94148, Indonesia
Institute of Transdisciplinary Science for Innovation, Kanazawa University, Kanazawa 920-1192, Japan)



Article Info

Publish Date
31 Jul 2026

Abstract

The Flores Sea in eastern Indonesia is a marine biodiversity hotspot within the Wallacea region, yet its bacterial community remains largely unexplored. This study aimed to characterize bacterial diversity in Flores Sea surface water by re-analyzing publicly available metagenomic data. Public shotgun metagenomic data was obtained from the NCBI Sequence Read Archive (SRA) under accession number SRR37631993 (Bioproject: PRJNA1437532), comprising 40,285,030 paired-end reads (2×150 bp) generated using the MGI DNBSEQ G50 platform. Quality trimming was performed using fastp v1.1.0. Taxonomic classification was conducted using Kraken2 v2.1.3 against the standard database (k2_standard_08gb_20230605), followed by species-level abundance estimation with Bracken. Diversity indices (Shannon, Simpson) were calculated based on relative abundance. The results showed that 13,041,976 reads (64.8% of total) were successfully classified, identifying 4,477 bacterial species with significant abundance. The Shannon diversity index (H') was 3.95, indicating very high diversity. The Simpson index (1-D) was 0.94, demonstrating high community evenness. The bacterial community was dominated by halophilic bacteria, with Halomonas meridiana as the most abundant species (19.7%), followed by Chromohalobacter salexigens (5.1%) and Idiomarina loihiensis (4.9%). The dominance of halophilic bacteria reflects adaptation to the marine environment. These findings provide the first baseline data on bacterial diversity in Flores Sea surface water based on a single public metagenomic sample, establishing a foundation for future microbial monitoring in the understudied Wallacea region.

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Journal Info

Abbrev

biodidaktika

Publisher

Subject

Biochemistry, Genetics & Molecular Biology Education Immunology & microbiology Social Sciences Other

Description

Biodidaktika : Jurnal Biologi dan Pembelajarannya is a peer-reviewed journal that covers research and review articles in Biology and Biology ...