Genomic adaptations in information processing underpin trophic strategy in a whole-ecosystem nutrient enrichment experiment

Abstract

Several universal genomic traits affect trade-offs in the capacity, cost, and efficiency of biochemical information processing underpinning metabolism and reproduction. We analyzed their role in mediating planktonic microbial community responses to nutrient enrichment in an oligotrophic, phosphorus-deficient pond in Cuatro Ciénegas, Mexico—one of the first whole-ecosystem experiments involving replicated metagenomic assessment. Mean bacterial genome size, GC content, total number of tRNA genes, total number of rRNA genes, and codon usage bias in ribosomal protein sequences were higher in the fertilized treatment, as predicted assuming oligotrophy favors lower information-processing costs while copiotrophy favors higher processing rates. Contrasting changes in trait variances also suggested differences between traits in mediating assembly under copiotrophic versus oligotrophic conditions. Trade-offs in information-processing traits are apparently sufficiently pronounced to play a role in community assembly as the major components of metabolism—information, energy, and nutrient requirements—are fine-tuned to an organism’s growth and trophic strategy.