Unique microbiome in organic matter-polluted urban rivers

Area of Science:

• Environmental microbiology
• Ecosystem dynamics
• Aquatic ecology

Background:

• Untreated wastewater discharge causes widespread organic matter pollution in urban rivers.
• Understanding microbial community assembly in these environments is crucial but limited.
• Developing countries face significant challenges due to high population density and inadequate wastewater treatment.

Purpose of the Study:

• To investigate microbial community assembly and driving processes in organic matter-polluted urban rivers.
• To identify key factors regulating prokaryotic and eukaryotic community structures.
• To compare assembly dynamics with other aquatic environments and reveal successional patterns.

Main Methods:

• Field study of 200 organic matter-polluted urban rivers across 82 cities in China and Indonesia.
• Laboratory water-sediment column experiments.
• Dissimilarity-overlap approach to analyze community assembly dynamics.

Main Results:

• A unique microbiome characterized by the significant roles of organic matter and geographic conditions was identified.
• Organic matter critically influences taxonomic composition.
• Assembly dynamics in polluted rivers showed universality distinct from eutrophic/oligotrophic waters.
• Prokaryotic communities were dominated by deterministic processes, while eukaryotic communities were stochastic.
• Water prokaryotic communities exhibited a three-phase cyclic succession related to organic matter pollution.

Conclusions:

• This study provides the first large-scale insight into microbial community assembly in organic matter-polluted urban rivers.
• Findings highlight the distinct assembly processes and successional patterns in these unique ecosystems.
• Understanding these dynamics is vital for the sustainable management of urban aquatic environments.