Distribution Of Soil Carbon And Nitrogen In Estuary Wetland Of Jiaozhou Bay

Estuary wetland is an important transition between land and sea, in which carbon and nitrogen cycle are important part of the global carbon and nitrogen cycle. The distribution pattern and cycle processes of carbon and nitrogen in the soil of Jiaozhou Bay estuary wetland are closely related to the nutrient cycling and transformation of terrestrial and marine ecosystem, and have an important effect on global ecosystem. The distribution of the wetland soil carbon and nitrogen reflect characteristics of nutrients content and distribution on wetland directly. It has an important influence both on the study of productivity and ecological stability of the wetland ecosystem, and on the study of the water quality and water environment on the adjacent waters. Therefore, the study of the characteristics of temporal and spatial distribution of soil carbon and nitrogen in estuary wetland is an important content of wetland study at present, and is important to study on the global circulation of nutrients.For the target of Jiaozhou Bay estuary wetland, 1ab simulation experiments about three soil samples come from field investigations respectively in April, July, October2014 were carried out. The temporal and spatial distribution characteristics of soil microbial biomass carbon(MBC), total carbon(TC) and total nitrogen(TN) in the soil of Jiaozhou Bay estuary wetland were studied, and focused on analysis the effects of soil physical and chemical properties on the temporal and spatial distribution characteristics of carbon and nitrogen in soil, and estimated the reserves of soil carbon, nitrogen reserves in Jiaozhou Bay estuary wetland. The study were carried on the samples come from Jiaozhou Bay estuary wetland about their dynamic change characteristics of soil carbon and nitrogen. It can provide the reference data for further evaluation of the stability and protection of Jiaozhou Bay estuary wetland ecosystem. The results of this study are as follows:(1) The space distribution and time variation characteristics of the soil carbon in Jiaozhou Bay estuary wetland were studied. It was found that the soil MBC content was higher than soil TC in different sites in the same month, and the variation range of surface soil MBC and TC contents were 12.225~160.424mg/kg, 2.2~11.5g/kg. In verticaldirection, the content of soil MBC gradually decreases with soil depth on the whole, and the content of soil MBC is maximum in 0-10 cm.The vertical distribution characteristics of soil TC content in the range of 0-60 cm were gradually decreased with soil depth. From the time perspective, dynamic seasonal variation of surface soil MBC and TC content in Jiaozhou Bay estuary wetland are changed in different sites, and this is mainly because these sites are affected by tidal action and the growth status and species distribution of vegetation. The soil TC, MBC content distribution in Jiaozhou Bay estuary wetland in the vertical direction is greater with the change of season, and the seasonal dynamic variation coefficient are 2.95%~61.39%、0.04%~138.32%, respectively. The study found that, soil physical and chemical properties, such as the soil moisture content, soil bulk density, will have great influence on the distribution of soil carbon in wetland. In addition,tidal effect, vegetation will also affect the temporal and spatial variation characteristics of soil carbon in Jiaozhou Bay estuary wetland.(2) The space distribution and time variation characteristics of the soil nitrogen in Jiaozhou Bay estuary wetland were studied. The study found that the surface soil TN content in different sites being 1.1~2.8g/kg. In vertical direction, the distribution characteristics of surface soil TN content are different. From the time perspective, dynamic seasonal variation of surface soil TN content in Jiaozhou Bay estuary wetland is changed in different sites, and this is mainly because these sites are affected by tidal action and the vegetation growth status and species distribution. Soil TN content distribution in Jiaozhou Bay estuary wetland in the vertical direction is not significant with the change of season,and the seasonal dynamic variation coefficient of soil TN content in these three months2.25%~15.39% 、 2.30%~22.71% 、 0~15.56%, respectively. The study found that, soil physical and chemical properties, such as the soil moisture content, soil bulk density, and p H,will have great influence on the distribution of soil nitrogen in wetland. The correlativity between soil nitrogen content and the physicochemical properties of soil are different in different seasons.(3) Reserves characteristics of soil TC and TN in Jiaozhou estuary wetland were studied. The results indicated that soil carbon reserves in 0-10 cm is highest in the soil profile of Jiaozhou estuary wetland in different sites, and the carbon reserves is gradually decreased with the increase of soil depth. For different samples, in April, July and October, the average values of soil carbon reserves are range from 4.19~7.70kg/m3, 4.08~7.62 kg/m3, 3.71~8.39kg/m3, respectively. In addition, the seasonal changes characteristics of soil carbon reserves areobvious in different soil layers, and the seasonal variation of soil carbon reserves is different in different soil layers. With the increase of soil depth, the total nitrogen in the reserves has no obvious changes in Jiaozhou estuary wetland. In April, July and October, the average value of soil nitrogen reserves are range from 2.56 to 3.48kg/m3、1.82 to 2.91 kg/m3、1.98 to2.56kg/m3, respectively. The seasonal variation of soil nitrogen reserves is different in different soil layers.