A bibliometric study on carbon cycling in vegetated blue carbon ecosystems.

Understanding carbon cycling in blue carbon ecosystems is key to sequestrating more carbon in these ecosystems to mitigate climate change. However, limited information is available on the basic characteristics of publications, research hotspots, research frontiers, and the evolution of topics related to carbon cycling in different blue carbon ecosystems. Here, we conducted bibliometric analysis on carbon cycling in salt marsh, mangrove, and seagrass ecosystems. The results showed that interest in this field has dramatically increased with time, particularly for mangroves. The USA has substantially contributed to the research on all ecosystems. Research hotspots for salt marshes were sedimentation process, carbon sequestration, carbon emissions, lateral carbon exchange, litter decomposition, plant carbon fixation, and carbon sources. In addition, biomass estimation by allometric equations was a hotspot for mangroves, and carbonate cycling and ocean acidification were hotspots for seagrasses. Topics involving energy flow, such as productivity, food webs, and decomposition, were the predominant areas a decade ago. Current research frontiers mainly concentrated on climate change and carbon sequestration for all ecosystems, while methane emission was a common frontier for mangroves and salt marshes. Ecosystem-specific research frontiers included mangrove encroachment for salt marshes, ocean acidification for seagrasses, and aboveground biomass estimation and restoration for mangroves. Future research should expand estimates of lateral carbon exchange and carbonate burial and strengthen the exploration of the impacts of climate change and restoration on blue carbon. Overall, this study provides the research status of carbon cycling in vegetated blue carbon ecosystems, which favors knowledge exchanges for future research.