# The failure and revival of closed microbial ecosystems: evidence from the shifts in microbial and chemical diversities

## TL;DR

This study examines how closed microbial ecosystems change over time, showing how shifts in microbial and chemical diversity affect ecosystem stability.

## Contribution

The study reveals a self-reinforcing feedback loop linking microbial diversity loss and chemical simplification in closed ecosystems.

## Key findings

- The ecosystem showed biphasic stability with initial dominance of Pseudomonas followed by Brevundimonas and Porphyrobacter.
- Loss of dissolved organic matter chemodiversity and accumulation of recalcitrant compounds correlated with declining carbon cycling.
- Microbial diversity erosion and chemical simplification create feedback loops threatening ecosystem persistence.

## Abstract

Closed microbial ecosystems (CES) are vital models for studying ecosystem stability and resilience, especially in carbon cycling. This study explored algae-bacteria CES using real-time pressure dynamics, 16S rRNA sequencing, and ultrahigh-resolution mass spectrometry. The system exhibited biphasic stability: an initial high-activity phase (Days 1–8) with robust carbon cycling and diverse communities dominated by Pseudomonas. Subsequent re-stabilization (Days 31–45) involved a functional shift toward Brevundimonas and photoheterotrophic Porphyrobacter, coupled with dissolved organic matter (DOM) chemodiversity loss and accumulation of recalcitrant lignin/Carboxyl-rich alicyclic molecules–like compounds. Declining carbon cycling intensity correlated with microbial diversity erosion and DOM simplification, revealing a self-reinforcing feedback loop threatening ecosystem persistence. This work advances frameworks for anticipating tipping points in natural ecosystems under anthropogenic stressors, offering actionable insights for conservation and bioremediation strategies.

Graphical Abstract