GEOGRAPHICAL RESEARCH ›› 2010, Vol. 29 ›› Issue (7): 1203-1212.doi: 10.11821/yj2010070006

• Environment and Ecology • Previous Articles     Next Articles

Spatial variations of carbon, nitrogen and phosphorous in tidal salt marsh soils of the Minjiang River estuary

TONG Chuan, JIA Rui-xia, WANG Wei-qi, ZENG Cong-sheng   

  1. Key Laboratory of Humid Subtropical Eco-geographical Process of Ministry of Education, Research Centre of Wetlands in Subtropical Region, School of Geographical Sciences, Fujian Normal University, Fuzhou 350007, China
  • Received:2009-08-05 Revised:2010-02-01 Online:2010-07-20 Published:2010-07-20

Abstract:

The Minjiang River estuary is a typical tidal estuary in the southeast of China, and the Shanyutan wetland (between 119°34'12″-119°40'40″E and 26°00'36″-26°03'42″N) is the largest estuarine wetland in the Minjiang River estuary area. The climate is relatively warm and wet, with a mean annual temperature of 19.6 ℃ and a mean annual precipitation of 1350 mm. The samples were collected in 18 soil profiles with a depth of 60 cm under three dominated macrophytes (Phragmites australis, Cyperus malacceusis var.bervifolius and Scirpus triqueter) in two different inundated districts far from and near a tide ditch in the middle of the Shanyutan wetland. These soil samples were divided into layers of 0-10, 10-20, 20-30, 30-40, 40-50 and 50-60 cm in depth. The soil properties and DOC, TN, TP, NH+4-N and NO-3-N contents and storages were measured. The concentrations of DOC in a depth of 0-10 cm ranged from 13.68 to 93.73 mg kg-1, TN from 0.24 to 1.91 g kg-1, and TP, 0.21-1.34 g kg-1. The DOC, TN and TP concentrations of the soils under P. australis and C. malacceusis were similar, which was higher than DOC and TN concentration under Scirpus triqueter in the area far from and near the tide ditch. The TN and TP contents and storages near the tide ditch were significantly higher than that far from the tide ditch for S.triqueter wetland, however, for the P. australis and C. malacceusis wetlands, the TN and TP contents in the area far from and near the tide ditch were similar. Besides, the DOC, TN and TP contents in soils were significantly correlated with the soil grain size, bulk density and moisture. The soil salinity values had a positive correlation with NH+4-N content, and a negative correlation with NO+3-N. The DOC, TN and TP contents in the Shanyutan tidal wetland were much similar with those in the Yangtze River and Pearl River estuaries, and some coastal regions across the world.

Key words: tidal salt marsh, Phragmites australis, Cyperus malaccensis var.bervifolius, Scirpus triqueter, soil, nutrient element, Minjiang River estuary