Seasonal change of sediment microbial communities in young and old mangrove forests in Xuan Thuy National Park
The present work was conducted in an estuarine mangrove ecosystem of Xuan Thuy National Park (XTP) in northern Vietnam. The XTP is located along the southern part of the Ba Lat Estuary of the Red River which is the largest river in northern Vietnam. The XTP covers a total wetland area of 12,000 ha, of which about 3000 ha are covered by mangrove forests. Generally, mangroves in the XTP can be classified into natural and planted mangrove forests. The natural mangrove forests are mainly distributed in the northern area of the XTP, dominated by the mangrove species Sonneratia caseolaris, Kandelia obovata, Aegiceras corniculatum, and Avicennia marina.The planted mangrove forests are mainly distributed in the southern part ofthe XTP, dominated by K. obovata (Hong et al., 2004). The mangrove ecosystems of the XTP are a valuable ecological and economic resource, providing essential nursery grounds formany species offishes, invertebrates, and waterfowl. The mangrove ecosystems are therefore a major stopover for migratory birds between northern and southern Asia (Thuy, 2004).Sediment samples were collected and their properties were measured in a K. obovata forest, which was planted in 1998. The mangrove forest were separated into two the different year-old mangroves forests (bellow 12 year and over 20 year old) by Tra river. The samples will be collected at different depth (0-5 cm; 15-20 cm; and 35-40 cm) at three sites in two forests. Field trips were carried out in dry season (Mar 2019) and wet season (Aug 2019).