水产养殖生态系统由于其高氮负荷而成为氧化亚氮(N2O)的潜在释放源,为探究其排放特征,选择福建省九龙江河口养虾塘为研究对象,采用悬浮箱-气相色谱仪法测定其水-气界面N2O排放通量变化,并结合气象要素和水环境因子分析其主要影响因素.结果表明:九龙江河口养殖塘水-气界面N2O排放通量的变化范围和均值分别为0.10～0.64μmol·m-2·h-1和(0.26±0.07)μmol·m-2·h-1,均表现为向大气释放N2O的源.N2O排放通量随养殖期推迟呈现持续增加,且在白天不同时刻存在显著变化.相关分析表明,N2O排放通量与养殖水体的温度、溶解性有机碳、NO-2-N和NO-3-N浓度呈显著正相关,与盐度呈显著负相关.多元回归分析表明,水体盐度和NO-2-N浓度是影响养虾塘N2O排放的主要因素.

氧化亚氮(N2O)是一种重要的痕量温室气体,对全球气温升高和酸雨形成起着重要作用,并对臭氧层造成严重损害.水产养殖是N2O的潜在释放源,该研究以中国东南沿海的闽江河口湿地围垦养虾塘为研究对象,采用过程抑制法,通过室内培养试验区分N2O不同产生过程及其对沉积物N2O总产生速率的贡献,在此基础上分析沉积物理化性质对N2O产生的影响.结果表明:养虾塘沉积物N2O总产生速率在养殖初期、中期和末期的均值分别为1.80、5.95和8.70 nmol/(kg·h),其中硝化作用、反硝化作用、硝化细菌反硝化作用和非生物作用的贡献率均值分别为?162.04％、327.52％、?239.45％和90.27％,从而得出结论:反硝化作用和非生物作用是产生沉积物N2O的主要来源,硝化作用和硝化细菌反硝化作用则对沉积物N2O的产生有所削弱;养虾塘沉积物N2O总产生速率在高温低盐条件下最大,在低温高盐条件下出现最小值,总体呈现随着温度升高而增加,随着盐度升高而降低的趋势;相关分析表明N2O总产生速率与总碳(total carbon,TC)、土壤有机碳(soil organic carbon,SOC)、NH4+-N含量和C:N比均呈显著正相关关系,而在其不同产生过程中仅有非生物过程受到TC、SOC含量的显著影响.

To clarify the effect of invasive alien plants on ecosystem functions, soil total carbon (TC), total carbon (TN), and total phosphorus (TP) contents were studied in the exotic invasive plant Spartina alterniflora marsh with different durations and the native species Cyperus malaccensis marsh in the Minjiang River estuary. The results showed that there were different variations of TC, TN and TP at 0-50 cm soil layer in the C. malaccensis marsh invaded by S. alterniflora, but the changes of TC and TN were similar and the change of the TP lagged behind them. Soil C/N increased continually with the increase of TC. Soil TP was a key factor affecting soil C/P and N/P during the S. alterniflora invasion, and the change of C/P and N/P followed a similar trend. The changes of TC, TN and TP were influenced by abiotic factors such as soil salinity, bulk density, soil water content and clay composition. C, N and P stoichiometric ratios were influenced mainly by soil salinity and grain composition. C/N and C/P were the good indicators for soil carbon enrichment ability in S. alterniflora marsh. S. alterniflora invasion induced the change of biomass and marsh habitats. Soil carbon, nitrogen, phosphorus contents, and their ecological stoichiometric ratios changed significantly in the C. malaccensis marsh invaded by S. alterniflora and showed diffe-rent change characteristics with different invasion duration.

The wetland landscape pattern and its dynamic change are the focus of wetland ecology and landscape ecology.There were lots of studies about the wetland landscape changes of long time series through the different periods,with little thinking of the seasonal changes of wetland landscape.In fact,the seasonal changes were also very obvious because of the water level and vegetation seasonal growth,especially in shallow lakes.In this paper,we took lake Caizi as an example,selected SPOT-5 images in April,August and December of the near year,interpreted lake wetland landscape based on RS/GIS,analyzed wetland landscape structure of the different seasons and their transformation each other according to statistics,and discussed the wetland landscape pattern index of the different seasons from the two levels of the landscape and the type by Fragstats software.The results showed that lake wetland landscape was mainly composed of water and the structure of wetland landscape had obvious seasonal variation by the level of the lake and the vegetation growth status.The seasonal changes of wetland landscape were implemented the reversible transfer among different types.With the structure of wetland landscape change,the landscape pattern indexes of landscape and types level had seasonal fluctuation.The study could provide the scientific basis for selecting remote sensing images which can be used in long time change of wetland landscape pattern in shallow lake.

To clarify the spatial and temporal variations of nitrogen under the coastal wetlands by Spartina alterniflora invasion,the contents and densities of various forms of nitrogen were measured to a depth of 50 cm in the soils of the native plant Cyperus malaccensis marshes and Spartina alterniflora invasion marshes across chronosequences of 0-4,4-8 and 8-4 years in the Min River Estuary.Their environmental factors were simultaneously measured.Results showed that total nitrogen and total organic nitrogen in the 0-20 cm of the Spartina alterniflora marshes increased continually with prolongation of the invasion,whereas they at depths of 30-50 cm decreased slightly at the beginning of the invasion period and exceeded the Cyperus malaccensis community 4-year post-invasion.Contents of ammonia nitrogen and nitrate nitrogen in 0-50 cm of the Spartina alterniflora marshes all increased continually with prolongation of the invasion years.Total nitrogen densities and total organic nitrogen densities in 0-10 cm,10-20 cm and 20-30 cm of the Spartina alterniflora marshes increased significantly 8-year invasion,4-year invasion and at the beginning of the invasion period,respectively.However,total nitrogen densities and total organic nitrogen densities in 30-50 cm both decreased slightly at the beginning of the invasion period and they increased in the 30-40 cm 4-year invasion and in 40-50 cm 8-year invasion.Ammonia nitrogen densities and nitrate nitrogen densities in 0-50 cm of the Spartina alterniflora marshes increased continually with prolongation of the invasion years.There were most significant positive correlation between most of the contents and storages of various nitrogen forms.Total organic nitrogen was an important part of soil nitrogen,which ratio total nitrogen had a rising trend with invasion years and soil depth.The correlation analysis showed that moisture,salinity and bulk density were significantly related with total nitrogen and total organic nitrogen,the nitrogen densities of various nitrogen forms were significant positive correlation with moisture and bulk density,meanwhile total nitrogen densities and total organic nitrogen densities had also significant correlation with salinity and soil particle size.In conclusion,Spartina alterniflora had strong nitrogen enrichment ability and enhanced effectively nitrogen storage of the unit area ecosystem in the estuary wetland,these were due to large amounts input of litter biomass,exogenous nitrogen deposition and soil physic-chemical properties.

As an effective blue carbon sinks to the mitigation of global warm, many studies have showed the changes of soil organic carbon (SOC) of coastal wetland invaded by C4 plant Spartina alterniflora, which is an alien species widely distributed in coastal areas of China. The regions were mainly grouped in Yancheng nature reserve, the Yangtze River estuary, Hangzhou Bay, Minjiang River estuary and Zhangjiang River estuary mangrove nature reserve and other large areas of Spartina alterniflora. These studies mainly compared the SOC distribution of coastal wetland pre-post invasion of Spartina alternifloraand their content variations with the invasion years and different seasons. Through analyzing and integrating relevant studies and data, the paper elaborated the effect of Spartina alterniflora invasion on the SOC of coastal wetland, compared the characteristic of spatial-temporal variations, and analyzed the influence factors on the SOC such as latitude, background plants before invasion, invasion period, hydrological regime, sampling depth and time, soil physic-chemical properties, and so on. Furthermore, in order to provide an important basis for assessment and reasonable regulation of carbon sinks in coastal wetlands, and deepen understanding of the global carbon cycle and global change, some problems of current research were discussed and some advice were put forward, including carrying out extensive long-term observation of carbon sink effect on Spartina alterniflora wetland, using high-resolution remote sensing images to identify plant types and space-time distribution of Spartina alterniflora, considering numerous factors for setting samples field, unifying field sampling method of wetland soil and experiment method analysis of organic carbon, emphasizing and strengthening comparative research on carbon sequestration and carbon release of Spartina alterniflora wetland.

为适应社会发展对人才培养的新要求,结合安庆师范学院环境专业教学实际,该文通过科学制定教学大纲、更新优化教学内容、革新教学手段与方法、加强实践教学等途径对该门课程的教学改革进行了探索,从而充分调动了学生的积极性和主动性,不断提高教学质量,取得了良好的教学效果.

In this paper,we analyze the current situation of the geography of higher education and talent cultivation,through the statistics on the setting-up of geography undergraduate specialty,the state of recruit students and the postgraduate training institutions of the secondary branch.It is found that the number of colleges and universities has obviously increased on basic of geography education,with a large-scale development of talent cultivation.But there are also some problems,such as uneven regional development,school-type single,quality of student and using title of geography.It is also obviously that the number of agencies which foster innovative humans of the post-graduate education are increased and the development of academic are enhanced,and especially Cartography and Geographic Information System has rapid ly developed.But there are also some problems,extremely uneven regional development,school-type single and so on.

The sulfur dioxide,the nitrogen oxide compound(by nitrogen dioxide)and the inspirable particles was selected,basing on the data of air pollutant between 2000 to 2005 obtained from environmental monitoring of Anqing to respect the distributing characteristics of year,season and area of Anqing City.The distributing characteristics were also analyzed in this article.