# Tagus River microbial profile through nanopore sequencing on samples gathered from Prainha do Braco de Prata, Lisbon

## TL;DR

This study analyzed microbial communities in the Tagus River using nanopore sequencing and found Candidatus Pelagibacter, Egibacter, and Ralstonia as dominant genera, which may be involved in organic matter decomposition.

## Contribution

The study provides a preliminary microbial profile of the Tagus River and highlights the potential of using microbial biomarkers to assess ecosystem services.

## Key findings

- Candidatus Pelagibacter, Egibacter, and Ralstonia were the most abundant genera in the Tagus River samples.
- These genera are likely involved in organic matter decomposition based on literature review.
- More robust sampling is needed to better understand the microbial ecosystem services in the river.

## Abstract

Freshwater ecosystems play a vital role for humans and more-than-humans, and their study can elucidate their dynamic state throughout time. However, there is not much knowledge about the microbial profiles and their relevance for the ecosystem balance is still unclear.

In this Brief Report three freshwater samples collected in the Tagus River north margin were analysed through 16S-targeted nanopore sequencing and by customized bioinformatics pipeline.

Our results revealed a consensual microbial profile with Candidatus
Pelagibacter,
Egibacter, and
Ralstonia as the most abundant genera. Additionally, through a literature review we found that the ecosystem services provided by these genera are mostly related to organic matter decomposition.

Despite the need for a more robust sampling and analyses, we conclude that there is potential to use microbial profile approaches to help define the relevant microbial biomarkers to clarify the ecosystem services in the Tagus River freshwater ecosystem.

Water is life and its quality is important to the natural balance. In this Brief Report we studied three water samples collected in the Tagus River, near Beato and found that Candidatus
Pelagibacter,
Egibacter, and
Ralstonia were the most abundant microbes detected. During our search for the role these microbes have in the river we concluded that there is not enough information about them. From what we observed, they are related to decompose organic matter, but there is a need to analyse more samples to have a clearer picture about the microbiology of the Tagus River.