Changes in sediment properties and bacterial community in marine sediments after entering the coastal land in Bohai Bay, northern China

摘要

In coastal areas of Bohai Bay, China, marine sediments were used for land reclamation. However, vegetation cannot grow well on the reclaimed land because marine sediments have different ecological functions than soil. Changing marine sediment into soil rapidly and accelerating the soil-forming process is key to solving this ecological problem on reclaimed land. Therefore, in this study, we not only measured the chemical properties of marine sediments during an 8 yr soil formation period to explore fertility changes, but we also used MiSeq sequencing to analyze and compare the bacterial community structure and diversity before and after the 8 yr land reclamation. Our results showed: (1) Marine sediment changed from severe to mild salinization during the 8 yr of soil formation, and the sediment salinity decreased significantly to 7.3 g kg-1 (p 0.05). However, pH of the sediment was always 8.5 and did not change significantly. In addition, the total fertility of the sediment decreased significantly after 8 yr. Especially, the content of nitrate-N in marine sediment decreased significantly by 86.23% (p 0.05) after 8 yr of soil formation. Also, the content of available P and soil organic matter decreased significantly by 45.92% and 26.22%, respectively. (2) The total abundance of bacteria increased while the community diversity decreased after the sediments were removed from the ocean environment for 8 yr. The bacterial community composition changed, and results of our redundancy analysis (RDA) indicated that the change was mainly affected by pH, soil contents including, available P, nitrate-N, ammonia-N, Na+, and Cl-, as well as salinity.