Microbial consortia in salt marsh sediments are sequentially buried over millennia and genomic complementarity analysis indicates an important role in complex carbon decomposition

Microbial Consortia in Salt Marsh Sediments and Their Role in Carbon Decomposition

Salt marshes play a crucial role in global carbon storage and have the potential to affect both climate change and coastal system stability. These sediments hold between 400 and 6500 teragrams (Tg) of organic carbon (Duarte et al. 2011) and annually sequester an additional 10.2 to 44.6 megatons (Mt), representing 0.5–1.0% of anthropogenic carbon emissions (Ouyang and Lee 2014).

However, the capacity of salt marshes to store carbon is decreasing. Over a recent nine-year period, loss of these habitats led to emissions of 16.3 Tg of CO2 and lowered CO2 burial by 0.045 Tg per year (Campbell et al.).

Rapid sea level rise and warming climates threaten the stability of existing organic carbon stocks, with uncertain consequences (Fontaine et al.).

Diversity and Metabolic Roles of Microbial Communities

Microbial communities in salt marsh sediments are diverse both compositionally and metabolically. Their interactions significantly impact soil organic carbon (SOC) pools (Bulseco et al.).

Despite this, critical gaps remain in understanding the metabolic capabilities and spatial distribution of these microbes. This often leads to the discovery of previously unknown carbon cycling pathways among novel microbial taxa (Payne et al.).

Understanding Microbial Influence on Carbon Pools

Identifying how microbial communities affect carbon pools is essential for advancing knowledge of blue carbon stock fate, formation processes, and temporal changes.

"Salt marsh sediments contain between 400 – 6500 Tg of organic carbon and store an additional 10.2 - 44.6 Mt annually, the equivalent of 0.5-1.0% of anthropogenic carbon emissions." (Duarte et al. 2011; Ouyang and Lee 2014)
"Salt marsh habitat loss resulted in emission of 16.3 Tg of CO2 and a reduction of 0.045 Tg of CO2 burial per year." (Campbell et al.)

Author's Summary: Microbial communities in salt marsh sediments play a vital role in complex carbon cycling, affecting blue carbon storage and its stability amid climate and sea level changes.

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eLife eLife — 2025-11-07

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