Functional biogeography of ocean microbes revealed through non-negative matrix factorization

Area of Science:

• Microbial Ecology
• Metagenomics
• Bioinformatics

Background:

• Metagenomic sequencing offers insights into microbial community structure and previously unknown taxa.
• Genotypic differences do not always equate to functional differences in microbes.
• There is a need to understand the large-scale distribution of microbial functions across various habitats.

Purpose of the Study:

• To develop a framework for investigating the biogeography of microbial function.
• To analyze the distribution of protein families across global sites using environmental sequence data.
• To explore the relationship between microbial function, environmental conditions, and geographic location.

Main Methods:

• Mapped over 6 million protein sequences from the Global Ocean Survey dataset to protein families.
• Generated a protein family relative abundance matrix.
• Applied non-negative matrix factorization (NMF) to identify ecological components and functional signatures.

Main Results:

• Identified common functional signatures within NMF-derived ecological components.
• NMF-filtered functional distance correlated more strongly with environmental distance than PCA-filtered measures.
• Functional distance showed a stronger correlation with environmental distance than geographic distance.

Conclusions:

• The proposed framework effectively maps microbial functions and their biogeography.
• Environmental factors are more influential than geographic distance in shaping microbial functional distribution.
• NMF and dimension reduction methods can facilitate a macroscopic functional understanding of marine ecosystems.