How nutrients and antibiotics shape microbial network patterns: Comparative insights from Erhai Lake bays

Area of Science:

• Environmental Microbiology
• Ecosystem Ecology
• Aquatic Chemistry

Background:

• Freshwater lakes face increasing nutrient enrichment and antibiotic pollution.
• The combined effects of these stressors on microbial network structure are poorly understood.

Purpose of the Study:

• To investigate the joint effects of nutrients and antibiotics on bacterial communities in Erhai Lake.
• To characterize microbial network structure across pollution gradients.

Main Methods:

• Bacterial communities were analyzed across eight bays in Erhai Lake, classified into high-, moderate-, and low-pollution zones.
• Nutrient (chemical oxygen demand, total nitrogen) and antibiotic (ofloxacin) levels were measured.
• Microbial network structure was assessed along the pollution gradient.

Main Results:

• High-pollution zones favored nutrient-tolerant species but showed fragmented, unstable networks.
• Moderate-pollution zones exhibited more stable and interconnected networks due to antibiotic resistance.
• Low-pollution zones had balanced networks, but potentially lower resilience to disturbances.

Conclusions:

• Nutrient enrichment and antibiotic pollution significantly impact microbial communities.
• Moderate pollution levels represent a critical stability period for microbial networks.
• Management interventions are crucial to prevent ecosystem destabilization and maintain lake health.