Methane seepage leads to a specific microplastic aging process in the simulated cold seep environment

Area of Science:

• Marine biology
• Environmental science
• Geochemistry

Background:

• Deep-sea cold seeps are significant sinks for marine microplastics.
• Limited research exists on microplastic aging under deep-sea conditions (low temp, dark, high pressure, methane-rich).

Purpose of the Study:

• To investigate microplastic aging in simulated deep-sea cold seep environments.
• To understand the influence of methane seepage on microplastic degradation.

Main Methods:

• Collected seawater and sediment from Haima cold seeps.
• Simulated seepage environments in high-pressure reactors.
• Monitored four microplastic types over two months.

Main Results:

• Methane seepage accelerated microplastic aging (surface roughness, bond formation, microbial colonization, contact angle).
• Aging was more pronounced in sediments than seawater; polylactic acid (PLA) showed significant aging.
• Aged microplastics disturbed inorganic nutrient levels, affecting the nitrogen cycle.

Conclusions:

• Deep-sea cold seeps significantly influence microplastic aging processes.
• Microplastic aging in these environments has ecological implications for nutrient cycling.
• Further research is needed to understand the full impact of aged microplastics in extreme marine ecosystems.