Intraspecific divergence within Microcystis aeruginosa mediates the dynamics of freshwater harmful algal blooms under climate warming scenarios

Intraspecific biodiversity can have ecosystem-level consequences and may affect the accuracy of ecological forecasting. For example, rare genetic variants may have traits that prove beneficial under future environmental conditions. The cyanobacterium responsible for most freshwater harmful algal blooms worldwide, Microcystis aeruginosa, occurs in at least three types. While the dominant type occurs in eutrophic environments and is adapted to thrive in nutrient rich conditions, two additional types have recently been discovered that inhabit oligotrophic and eutrophic environments and have genomic adaptations for survival under nutrient limitation. Here, we show that these oligotrophic types are widespread throughout the Eastern USA. By pairing an experimental warming study with gene expression analyses, we found that the eutrophic type was most susceptible to climate warming. In comparison, oligotrophic types maintained their growth better and persisted longer under warming. As a mechani..., , , # README: Intraspecific divergence within *Microcystis aeruginosa* mediates the dynamics of freshwater harmful algal blooms under climate warming scenarios.

## Description of the data and file structure

This repository is associated with Kuijpers, M. C. M.; Quigley, C. V.; Bray, N. C.; Ding, W.; White, J. D.; & Jackrel, S. L. (2025). Intraspecific divergence within *Microcystis aeruginosa* mediates the dynamics of freshwater harmful algal blooms under climate warming scenarios. PRSB. In Press.

In this study, we first show that previously discovered oligotrophic types of Microcystis aeruginosa are widespread throughout the Eastern USA. By pairing an experimental warming study with gene expression analyses, we then show that the common eutrophic type may be most susceptible to climate warming. In comparison, we find that oligotrophic types maintained their growth better and persisted longer under warming. As a potential mechanistic explanation for these patterns, we then show that ...