Black carbon structuring marine microbial activities and interactions: a micro- to macro-scale interrogation.

Area of Science:

• Marine microbial ecology
• Biogeochemistry
• Environmental science

Background:

• Black carbon (BC) from combustion is a significant climate forcer.
• BC enters marine environments through deposition and runoff.
• BC's impact on marine microbial processes is not fully understood.

Purpose of the Study:

• To investigate the short-term effects of high black carbon loads on marine microbial dynamics and activities.
• To understand how microbes interact with BC particles in the marine environment.

Main Methods:

• Incubation experiments in the Adriatic and Ligurian Seas with high BC concentrations (24 mg L⁻¹).
• Microbial abundance and activity measurements (prokaryotic carbon production, enzyme activities).
• Microscopy (FTIR, AFM) and 16S rRNA gene amplicon sequencing.

Main Results:

• Increased abundance of heterotrophic prokaryotes and decreased viral counts upon BC amendment.
• Microbes attached to BC particles, which were protein-enriched.
• Suppressed protease and phosphatase activities, despite enhanced prokaryotic carbon production.
• No significant shift in overall microbial community structure, but specific genera (Arcobacter, Pseudoalteromonas) associated with BC.

Conclusions:

• Black carbon stimulates significant carbon flow through marine microbial activity.
• Microbial communities show adaptive strategies to utilize BC.
• Anthropogenic carbon, like BC, is a crucial factor in marine biogeochemical carbon cycling.