The emerging pollutants HABs and microplastics: Impact on microbial communities in the Mediterranean Sea

The Mediterranean Sea faces mounting environmental pressure from warming, pollution, urbanization, and coastal development, driving biodiversity loss and habitat degradation with direct consequences for human health, food security, and the economic and social well-being of coastal populations. Marine microbial communities, bacteria, viruses, microbial eukaryotes, and archaea, respond rapidly and strongly to these disruptions, reorganizing their structure and shifting their functional roles. Because of this sensitivity, microbial communities offer one of the earliest and most informative signals of broader ecosystem change, making them a critical lens through which to track the health of the Mediterranean basin.

Two stressors are of particular concern. First, the Mediterranean is recognized as one of the highest accumulation zones for marine plastic waste worldwide. Microplastics (<5mm) behave as artificial microbial reefs, creating novel surfaces that reshape the composition, diversity, and function of microbial communities and that can have synergistic effects on their development, transport, persistence, and broader ecology. Second, the Mediterranean is projected to experience some of the most visible and consequential impacts of climate change of any sea, including a rise in the frequency, duration, and intensity of harmful algal blooms (HABs). HABs are already a recurrent phenomenon in the region, and their intensification under warming is expected to further reshape the diversity and dynamics of marine microbial communities in ways that are not yet well understood.

This Research Topic aims to improve understanding of how HABs and microplastic pollution, both individually and in combination, affect the diversity, structure, and ecological functioning of marine microbial communities in Mediterranean coastal ecosystems. We welcome studies investigating the responses of planktonic microbial communities to these stressors across coastal and offshore waters of the Mediterranean Sea, using high-throughput sequencing approaches to examine archaea, bacteria, and microbial eukaryotes and to characterize how these groups shift under environmental pressure.

Specific themes include, but are not limited to:

- Community structure and diversity, including shifts in microbial communities during HAB events and the identification of indicator taxa linked to HABs or microplastic exposure
- Microbial interactions with HAB species, including patterns of microbial succession during bloom development and decline, and microbes that promote or inhibit algal blooms
- Identification and characterization of microbial assemblages forming the plastisphere
- Comparative differences between plastic-associated and free-living microbial communities
- Microbial roles in the degradation of algal toxins, plastics, and hydrocarbons
- Broader ecological and biogeochemical impacts of these stressors on Mediterranean coastal systems

Article types: Original Research, Review, and Mini Review.

Article types and fees

This Research Topic accepts the following article types, unless otherwise specified in the Research Topic description:

• Brief Research Report
• Data Report
• Editorial
• FAIR² Data
• General Commentary
• Hypothesis and Theory
• Methods
• Mini Review
• Opinion
• ... View all formats

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Article types

This Research Topic accepts the following article types, unless otherwise specified in the Research Topic description:

• Brief Research Report
• Data Report
• Editorial
• FAIR² Data
• General Commentary
• Hypothesis and Theory
• Methods
• Mini Review
• Opinion
• Original Research
• Perspective
• Policy and Practice Reviews
• Policy Brief
• Review
• Systematic Review
• Technology and Code

Keywords: Harmful algal blooms (HABs), Microplastics / plastisphere, Marine microbial community diversity, Mediterranean coastal ecosystems, Microbial biogeochemical cycling, High-throughput sequencing, Emerging pollutants and marine microbiology, Mediterranean Sea

Important note: All contributions to this Research Topic must be within the scope of the section and journal to which they are submitted, as defined in their mission statements. Frontiers reserves the right to guide an out-of-scope manuscript to a more suitable section or journal at any stage of peer review.