Seasonal variations in biomass, height, photosynthetic efficiency, and carbon and nitrogen contents of Suaeda japonica in Incheon salt marshes (Korea)

Jeong Hwa Hwang ¹ Ji-sook Park ¹ Young-Seok Han ² Charles Yarish ³ Jang Kyun Kim ^1*

• ¹ Incheon National University, Incheon, Republic of Korea
• ² NEB, Seoul, Republic of Korea
• ³ University of Connecticut, Storrs, Connecticut, United States

Salt marshes are known for their higher carbon absorption capacity and productivity compared to terrestrial ecosystems. However, in Korea, human activities have led to a reduction in these vital coastal habitats. This study observed seasonal changes in vegetation, photosynthetic efficiency, carbon and nitrogen content of Suaeda japonica at two salt marsh ecosystems in Incheon, Korea, Yeongjong and Sorae, namely YJ and SR. In spring, plant density at S. was significantly higher than at YJ. This higher density at SR. inhibited growth and survival during summer and fall. In addition, photosynthetic efficiency at SR. was greatly decreased in summer compared to spring. The different habitat densities between the sites resulted in morphological differences. The plants at YJ, with lower density, grew wider with more branches and showed higher dry weight in comparison to those at SR. Carbon sequestration by S. japonica per unit area was about 113.70 g/m 2 at YJ, which is twice as high as at SR. The tissue carbon content was highest in the roots, suggesting that carbon absorbed by the leaves is effectively stored as sediment. This study confirmed annual changes in salt marsh vegetation and quantified carbon sequestration. The characteristics of salt marsh plant as regional and seasonal change highlight the importance of salt marshes as a blue carbon resource and underscore the need for salt marsh restoration projects.