# Foundation species stabilize an alternative eutrophic state in nutrient-disturbed ponds via selection on microbial community

## TL;DR

This study shows that foundation species like mussels and macrophytes can stabilize turbid eutrophic states in ponds by influencing microbial communities.

## Contribution

The study demonstrates how foundation species can stabilize prokaryotic communities and promote eutrophic states in nutrient-disturbed ponds.

## Key findings

- Nutrient disturbance and foundation species strongly affect prokaryotic community composition and stability.
- Foundation species stabilize prokaryotic communities post-disturbance by reducing changes in community composition.
- Prokaryotic community changes directly and indirectly alter ecosystem properties like pH and dissolved oxygen.

## Abstract

Eutrophication due to nutrient addition can result in major alterations in aquatic ecosystem productivity. Foundation species, individually and interactively, whether present as invasive species or as instruments of ecosystem management and restoration, can have unwanted effects like stabilizing turbid eutrophic states. In this study, we used whole-pond experimental manipulations to investigate the impacts of disturbance by nutrient additions in the presence and absence of two foundation species: Dreissena polymorpha (a freshwater mussel) and Myriophyllum spicatum (a macrophyte). We tracked how nutrient additions to ponds changed the prokaryotic and eukaryotic communities, using 16S, 18S, and COI amplicon sequencing. The nutrient disturbance and foundation species imposed strong selection on the prokaryotic communities, but not on the microbial eukaryotic communities. The prokaryotic communities changed increasingly over time as the nutrient disturbance intensified. Post-disturbance, the foundation species stabilized the prokaryotic communities as observed by the reduced rate of change in community composition. Our analysis suggests that prokaryotic community change contributed both directly and indirectly to major changes in ecosystem properties, including pH and dissolved oxygen. Our work shows that nutrient disturbance and foundation species strongly affect the prokaryotic community composition and stability, and that the presence of foundation species can, in some cases, promote the emergence and persistence of a turbid eutrophic ecosystem state.