Carbon Sequestration in Coastal Wetlands: Global Trends and Black Sea Evidence Gaps
Keywords:
coastal wetlands, blue carbon, carbon sequestration, bibliometric analysis, VOSviewer, Black SeaAbstract
Coastal wetlands store substantial quantities of carbon and can contribute to climate change mitigation. This study examined the global structure of coastal wetland carbon research and assessed the extent and characteristics of the available evidence for Black Sea coastal wetlands. It combined a global bibliometric analysis with a geographically focused review of carbon research in the Black Sea coastal area. The global set comprised 2,962 English-language articles and reviews retrieved from Scopus and analyzed in VOS viewer through keyword co-occurrence and country co-authorship analyses. Separate regional searches in Scopus and Open Access were used to assess the indexed peer reviewed evidence for the Black Sea. The keyword map identified four interconnected themes: soil-carbon biochemistry, blue-carbon ecosystems and management, greenhouse gas exchange and carbon fluxes, and sedimentary carbon assessment. The country network revealed extensive but regionally structured international collaboration. In contrast, only five eligible regional studies were identified: three concerning the Romanian sector of the Danube Delta and two involving sites on the Bulgarian coast. These studies focused mainly on soil, sediment and biomass carbon stocks and the effects of human management, while complete greenhouse gas balances and direct sequestration rates remained largely unassessed. No eligible studies were retrieved for the coastal wetlands of Georgia, Türkiye or Ukraine. The findings reveal a stark contrast among the broad global research landscape and the small, geographically concentrated Black Sea evidence base. Coordinated basin-wide monitoring, standardized measurement protocols and direct assessment of carbon dioxide, methane and nitrous oxide would help strengthen the evidence base and support site-specific conservation and restoration decisions.
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