Nitrogen cycling of atmosphere-plant-soft system in the typical Calamagrostis angustifolia wetland in the Sanjiang Plain,Northeast China

The nitrogen(N)distribution and cycling of atmosphere-plant-soil system in the typical meadow Calamagrostis angustifolia wetland (TMCW)and marsh meadow Calamagrostis angustifolia wetland(MMCW)in the Sanjiang plain were studied by a compartment model.The results showed that the N wet deposition amount was 0.757 gN/(m~2.a),and total inorganic N(TIN)was the main body (0.640 gN/(m~2.a)).The ammonia volatilization amounts of TMCW and MMCW soils in growing season were 0.635 and 0.687 gN/m~2, and the denitrification gaseous lost amounts were 0.617 and 0.405 gN/m~2,respectively.In plant subsystem,the N was mainly stored in root and litter.Soil organic N was the main N storage of the two plant-soil systems and the proportions of it were 93.98% and 92.16%, respectively.The calculation results of N turnovers among compartments of TMCW and MMCW showed that the uptake amounts of root were 23.02 and 28.18 gN/(m~2.a)and the values of aboveground were 11.31 and 6.08 gN/(m~2.a),the re-translocation amounts from aboveground to root were 5.96 and 2.70 gN/(m~2.a),the translocation amounts from aboveground living body to litter were 5.35 and 3.38 gN/(m~2.a),the translocation amounts from litter to soil were larger than 1.55 and 3.01 gN/(m~2.a),the translocation amounts from root to soil were 14.90 and 13.17 gN/(m~2.a),and the soil(0-15 cm)N net mineralization amounts were 1.94 and 0.55 gN/(m~2.a), respectively.The study of N balance indicated that the two plant-soil systems might be situated in the status of lacking N,and the status might induce the degradation of C.angustifolia wetland.     

Sulfur cycle in the typical meadow Calamagrostis angustifolia wetland ecosystem in the Sanjiang Plain, Northeast China

The sulfur cycle and its compartmental distribution within an atmosphere-plant-soil system was studied using a compartment model in the typical meadow Calamagrostis angustifolia wetland in the Sanjiang Plain Northeast China. The results showed that in the typical meadow C. angustifolia wetland ecosystem, soil was the main storage compartment and current hinge of sulfur in which 98.4% sulfur was accumulated, while only 1.6% sulfur was accumulated in the plant compartment. In the plant subsystem, roots and litters were the main storage compartment of sulfur and they remained 83.5% of the total plant sulfur. The calculations of sulfur turnover through the compartments of the typical meadow C. angustifolia wetland ecosystem demonstrated that the above-ground component took up 0.99 gS/m2 from the root, of which 0.16 gS/m2 was translocated to the roots and 0.83 gS/m2 to the litter. The roots took in 1.05 gS/m2 from the soil, subsequent translocation back to the soil accounted for 1.31 gS/m2, while there was 1.84 gS/m2 in the litter and the net transfer of sulfur to the soil was more than 0.44 gS/(m2·a). The emission of H2S from the typical meadow C. angustifolia wetland ecosystem to the atmosphere was 1.83 mgS/(m2·a), while carbonyl sulfide (COS) was absorbed by the typical meadow C. angustifolia wetland ecosystem from the atmosphere at the rate of 1.76 mgS/(m2·a). The input of sulfur by the rainfall to the ecosystem was 4.85 mgS/m2 during the growing season. The difference between input and output was 4.78 mgS/m2, which indicated that sulfur was accumulated in the ecosystem and may cause wetland acidify in the future.     

模拟湿地水分变化对小叶章枯落物分解及氮动态的影响

2005年5月-2006年9月,利用三江平原典型碟形洼地的自然水分梯度作为水分变化研究的替代系统,结合分解袋法,模拟研究了湿地水分变化对典型草甸小叶章(TMC)和沼泽化草甸小叶章(MMC)枯落物分解及氮动态的可能影响.试验沿水分梯度设漂筏苔草群落(PF)、毛果苔草群落(MG)、乌拉苔草群落(WL)、沼泽化草甸小叶章群落(XII)、典型草甸小叶章群落(XI)和岛状林群落(DZL)6个分解小区.研究表明.水分条件对枯落物分解有重要影响,当未来降水格局变化导致小叶章湿地形成积水环境后,TMC和MMC枯落物的失重率分别将增加4.33%-16.76%和24.84%-53.97%.分解速率将增加10.51%-32.73%和77.85%-93.92%,95%分解时间将减少0.72-1.85 a和3.67-4.05 a;TMC和MMC枯落物的氮含量及氮积累指数的变化较为一致.但不同小区间的变化模式差异较大.二者枯落物的氮在DZL、XI、WL、MG和PF小区整体上均表现处出释放累积的交替变化特征.但仍以释放过程为主.在XII小区,氮在整个时期一直表现为释放.C/N分解过程中氮养分的调控作用更为重要;TMC和MMC枯落物的氮现存量分别为12.75 g·m-2和8.29 g·m-2.氮年归还量分别大于1.95 g·(m2·a)-1和2.25g·(m2·a)-1;温度对枯落物相对分解速率具有促进作用,水分条件对其具有抑制作用.当分解环境的养分状况不发生较大变化时,相对分解速率取决于枯落物基质质量,当养分状况发生较大改变时,相对分解速率取决于环境养分供给状况.     

三江平原小叶章湿地H2S和COS排放动态

利用静态箱/气相色谱法，观测了生长季（5～9月）三江平原小叶章沼泽化草甸H₂S和COS的释放动态，结果表明，H₂S、COS的排放通量具有季节和日变化规律，小叶章沼泽化草甸H2S的平均释放通量为0.34 μg·(m²·h)^-1，COS的平均释放通量为－0.29μg·(m²·h)^-1；在生长季，小叶章沼泽化草甸表现为H₂S的源，COS的汇。小叶章的生长过程对H₂S、COS的排放影响显著，在小叶章生长旺盛期，H₂S出现排放峰值，COS出现吸收高峰，H₂S和COS的释放通量呈负相关。     

不同水文情势下环形湿地土壤铁的时空分布特征

通过分季节原位采集三江平原环形湿地不同深度的土壤和土壤溶液,调查了土壤总铁的空间分布和土壤溶液中可溶性铁的时间变化,分析了水文情势对这种铁时空分异的影响.结果表明,环形湿地0～60 cm土层总铁的平均含量为（2.54±0.73）×10⁴mg·kg^-1,且随地表积水深度的增加由小叶章群落和乌拉苔草群落的（2.91±0.51）×10⁴ mg·kg^-1和（2.60±0.35）×10⁴mg·kg^-1逐渐下降到毛苔草和漂筏苔草群落的（2.48±0.31）×10⁴mg·kg^-1和（2.17 ± 0.31）×10⁴mg·kg^-1;常年积水土壤中铁的可溶性高于季节性积水土壤;从春季化冻开始,土壤溶液中的可溶性铁含量随积水时间的延长而逐渐增加,从6月的（0.35±0.086） mg·L^-1增加到10月上冻前的（12.67±2.92） mg·L^-1;以Fe³⁺/Fe²⁺表征的土壤还原性随积水深度或浸没时长的增加而增加;土壤溶液中的可溶性铁与pH、总有机碳、总氮和磷酸盐都具有显著或极显著相关,表明铁的分布还受土壤理化性质的影响,并与土壤碳、氮、磷的迁移转化相耦合.     

潜流人工湿地中氮磷污染物净化的分层效应研究

选定芦苇、小叶章为湿地植物,土壤、炉渣为基质,构建3个小型潜流人工湿地系统,通过间歇运行方式,考察了模拟系统上层、下层中N、P和pH值等指标的变化.结果表明,当水力停留时间为10 d时,小叶章和芦苇湿地上层总氮的去除负荷分别为0.771 g·(m2·d)-1和1.481 g·(m2·d)-1,分别是下层的1.15倍和1...     

Influence of environment and substrate quality on the decomposition of wetland plant root in the Sanjiang Plain, Northeast China

The litterbag method was used to study the decomposition of wetland plant root in three wetlands along a water level gradient in the Sanjiang Plain,Northeast China.These wetlands are Calamagrostis angustifolia(C.aa),Carex meyeriana(C.ma)and Carex lasiocarpa (C.la).The objective of our study is to evaluate the influence of environment and substrate quality on decomposition rates in the three wetlands.Calico material was used as a standard substrate to evaluate environmental influences.Roots native to each we...     

开垦利用对三江平原湿地土壤硫含量的影响

以三江平原典型类型湿地及不同开垦年限的耕地 (旱田 )为研究对象 ,对其土壤中总硫及各形态硫的含量变化进行分析 ,结果如下 :总硫、水溶性硫、吸附性硫、盐酸可溶性硫、盐酸挥发性硫及有机硫含量排序均为小叶章 (Calamagrostisangusti folia)草甸 <乌拉苔草 (Carexmeyeriana)沼泽 <毛果苔草 (Carexlasiocarpa)沼泽 ;湿地开垦为耕地后 ,除盐酸可溶性硫含量增加以外 ,其余硫组分的含量均有不同程度的降低 ;耕地土壤中总硫及有机硫含量随开垦年限的增加而下降 ,而无机硫各组分随开垦年限的增加变化量不大 .湿地开垦前土壤总硫量为 6 2 2 4mg kg ,湿地开垦 2 0年后 ,土壤总硫量降低为 16 8mg kg ,因此在人类活动的干预下湿地开垦后表现出由汇转化为源 ,由累积转化为分散的特征     

垦殖方式对小叶章湿地表土团聚体有机碳分布的影响

研究了2种垦殖方式对三江平原小叶章湿地表土团聚体及其有机碳分布的影响.结果表明,垦殖后,粒径>0.25mm的大团聚体呈降低趋势,大豆田中0.053~0.25mm微团聚体增加;水稻田中主要增加的是1mm及0.053~0.25mm团聚体有机碳含量降幅均呈现大豆田大于水稻田,水稻田>大豆田,小叶章湿地>大豆田>水稻田.水稻田比大豆田土壤有机碳储量稍高,但其微团聚体有机碳储量及其占土壤有机碳储量的比例低于大豆田,开垦为大豆田比开垦为水稻田有利于土壤有机碳长期存留.     

三江平原沼泽湿地N2O浓度与排放特征初步研究

2001年8月到9月在三江平原沼泽湿地进行N₂O的原位静态箱观测.结果发现近地气层N₂O平均浓度为281.7×10^-9m³/m³,低于大气背景浓度,说明沼泽湿地可能是人类目前了解较少但很重要的N₂O汇.选取积水状况和地表植被不同的毛果苔草沼泽、小叶章湿草甸(Ⅰ,Ⅱ)以及作为对照的小麦休耕地进行观测,发现4个地点的N₂O排放日变化形式不完全相同,除小麦田全天持续排放N₂O外,其余各点一天当中均出现排放与吸收交替出现的情况.温度是影响排放模式的主要因素.观测期内毛果苔草沼泽、小叶章湿草甸(Ⅰ,Ⅱ)和小麦休耕地N₂O的平均排放强度分别为0.22μg/(m²·h),1.75μg/(m²·h),1.31μg/(m²·h)和4.86μg/(m²·h).氧化还原电位是决定沼泽湿地N₂O排放特征的关键因子,地表积水情况和土壤水分状况则是影响N₂O排放的另一重要因素.     

三江平原不同土地利用方式下凋落物对土壤呼吸的贡献

运用Li-6400土壤呼吸配套系统研究了三江平原沼泽湿地不同土地利用方式下保留和去除凋落物的土壤呼吸特征,进而分析了不同土地利用方式下凋落物对土壤呼吸的贡献及其与凋落物输入量和环境因子(温度、降水等)之间的相互关系.结果表明,整个生长季4种土地利用方式下凋落物对土壤呼吸的平均贡献量在-0.21~0.64μmol/(m2.s)之间,贡献率表现为小叶章草甸湿地(14%)人工林地(12%)大豆田(8%)退耕还湿地(-5%).其中,退耕还湿后凋落物对土壤呼吸的贡献表现为负值,减少了土壤呼吸的排放,表明凋落物对土壤呼吸的贡献可能最终取决于凋落物分解与屏蔽作用之间的平衡.除大豆田外,不同土地利用方式下凋落物对土壤呼吸的贡献均与10 cm地温达到了极显著相关关系(p0.01).另外,降雨的影响与凋落物输入密切相关,表明凋落物除自身分解外,还可能参与到气候变化的生态效应中.     

滇西北纳帕海高原湿地区域退化草甸土壤有机碳含量特征

为了解气候变化和人类活动双重影响下纳帕海高原湿地区域有机碳含量特征,采用空间格网状抽样调查方法,对区域内退化系列下湿地草甸w（SOC）（SOC为土壤有机碳）特征进行研究.结果表明:① 随着草甸的退化及土壤深度的增加,土壤含水量呈下降趋势,土壤容重呈增加趋势;② 从无退化草甸到重度退化草甸,植被地上生物量从321.4 g/m2降至142.1 g/m2;③ 在地表至地下50 cm深度范围内,从无退化到重度退化草甸,w（SOC）分别为28.21、20.59、18.01、14.81 g/kg,湿地草甸退化导致w（SOC）下降了近50%,ρ（SOC）从40.92 kg/m3降至25.23 kg/m3;④ 狼毒草甸的w（SOC）、ρ（SOC）等均表现出相对较高的水平,仅次于无退化样地;⑤ w（SOC）与土壤含水量呈显著正相关（P < 0.05）、与土壤容重呈显著负相关（P < 0.01）.湿地草甸植被退化所形成的地上植被盖度及生物量的下降,以及土壤含水量的下降和土壤容重的增加,最终导致近50%左右的w（SOC）发生流失;此外,若从同类研究中季节性淹水的沼泽或沼泽化草甸转变为该研究中常年出露于水面的草甸景观后,在20 cm土壤深度内将导致45%以上的w（SOC）损失.      

水翁(Cleistocalyx operculatus)在人工湿地的生长特性及对污染物的去除效果

研究了水翁在人工湿地的生长特性及其对污水的净化效果.结果表明:生长在人工湿地的水翁具有发达的侧根系,能保持正常的净光合速率((19.2±2.1)μmol/(m2·s))、蒸腾速率((23.5±2.3)mmol/(m2·s))、气孔传导率((657.5±53)mmol/(m2·s))、根系活力((20.9±3.2)μg/(g·min))和生长速率((9.9±0.5)mg/(g·d)).水翁人工湿地对TN,TP,C0D_cr和BOD₅的去除率分别为55.6%,44.2%,75.7%和73.2%.其中水翁对N,P的吸收量分别占人工湿地对N,P去除量的16.4%和12.6%.水翁为常绿乔木,可考虑与灌木和草本植物结合起来,建立乔、灌、草自然湿地系统,达到改善水质的目的.      

气候变化情景下湿地净初级生产力风险评价

采用BIOME-BGC模型,模拟了气候变化情景下(A1B, A2, B2)三江平原富锦地区小叶章(Calamagrostis angustifolia)湿地的净初级生产力(NPP)变化,并通过NPP变化情况评价小叶章湿地风险等级.结果表明:未来30年(2013~2042年)各气候情景下富锦小叶章湿地NPP均值均高于基准期均值(1961~1990), A1B和B2情景下未来30年间NPP波动范围变大,A2情景下NPP有降低趋势.风险评价结果表明,气候变化情景下小叶章湿地存在一定风险,尤其是在A1B情景下,未来30年中可能有6年以上的年份存在高风险,A2情景下湿地风险最低.湿地NPP变化与降水量呈显著正相关(R2=0.58,P<0.05),说明降水量是影响区域湿地的重要因素.尽管气候变化情景下假设了存在升温?CO2浓度升高等有利于植物生长的因素,但降水量的的剧烈变化以及极端气候事件的增加,可能会导致湿地在未来气候变化情景下面临较高风险,未来湿地保护与管理过程中应重点关注水的补给和调配.     

三江平原不同退化阶段小叶章湿地土壤真菌群落结构组成变化

为了了解三江平原小叶章湿地真菌群落结构及多样性变化,探讨湿地水分下降对真菌群落结构的影响.本研究采用高通量测序技术,分析和比较了黑龙江省科学院自然与生态研究所三江平原野外试验研究站内3个不同退化阶段小叶章生态类型湿地真菌群落结构多样性,探讨真菌群落改变的原因.结果表明,从小叶章沼泽湿地(w0)→小叶章沼泽化草甸湿地(w1)→小叶章草甸湿地(w2)的变化,土壤Shannon-Wiener指数(H)呈现出逐步上升的规律,即:w0w1w2.序列比对结果显示,不同小叶章湿地土壤真菌分别属于子囊菌(Ascomycota)、担子菌(Basidiomycota)、壶菌(Chytridiomycota)、未知菌(Fungi_unclassified)、接合菌(Zygomycota)这5个真菌类群,优势菌门为未知菌门(75.12%)、子囊菌门(56.56%)、担子菌门(72.65%).而且Heatmap分析也显示沼泽化草甸湿地和草甸湿地的真菌群落结构和组成比较接近.真菌群落结构受到了土壤养分以及植物组成等影响,其中土壤养分解释贡献率达88.62%,植物组成解释贡献率达到9.85%.三江平原小叶章湿地不同退化阶段湿地真菌群落结构存在较大差异,土壤水分因子对真菌多样性影响较大.这为研究三江平原湿地退化后的真菌结构多样性及空间异质性提供了科学依据.     

Effects of elevated CO2 concentration and nitrogen supply on biomass and active carbon of freshwater marsh after two growing seasons in Sanjiang Plain, Northeast China

An experiments were carried out with treatments di ering in nitrogen supply (0, 5 and 15 g N/m2) and CO2 levels (350 and 700 mol/mol) using OTC (open top chamber) equipment to investigate the biomass of Calamagrostis angustifolia and soil active carbon contents after two years. The results showed that elevated CO2 concentration increased the biomass of C. angustifolia and the magnitude of response varied with each growth period. Elevated CO2 concentration has increased aboveground biomass by 16.7% and 17.6% during the jointing and heading periods and only 3.5% and 9.4% during dough and maturity periods. The increases in belowground biomass due to CO2 elevation was 26.5%, 34.0% and 28.7% during the heading, dough and maturity periods, respectively. The responses of biomass to enhanced CO2 concentrations are di ered in N levels. Both the increase of aboveground biomass and belowground biomass were greater under high level of N supply (15 g N/m2). Elevated CO2 concentration also increased the allocation of biomass and carbon in root. Under elevated CO2 concentration, the average values of active carbon tended to increase. The increases of soil active soil contents followed the sequence of microbial biomass carbon (10.6%) > dissolved organic carbon (7.5%) > labile oxidable carbon (6.6%) > carbohydrate carbon (4.1%). Stepwise regressions indicated there were significant correlations between the soil active carbon contents and plant biomass. Particularly, microbial biomass carbon, labile oxidable carbon and carbohydrate carbon were found to be correlated with belowground biomass, while dissolved organic carbon has correlation with aboveground biomass. Therefore, increased biomass was regarded as the main driving force for the increase in soil active organic carbon under elevated CO2 concentration.     

三江平原不同类型小叶章湿地土壤细菌群落功能多样性

为全面了解三江平原小叶章湿地土壤细菌功能多样性的变化规律,采用Biolog-ECO微平板法对三江平原内不同类型小叶章湿地(草甸化小叶章湿地、沼泽化草甸小叶章湿地和沼泽化小叶章湿地)的土壤细菌群落功能多样性变化规律和特点进行分析.结果表明:不同类型小叶章湿地土壤理化性质差异显著(P<0.05).土壤细菌群落平均颜色变化率(AWCD)随培养时间的延长而增加,不同类型湿地土壤细菌群落代谢活性表现为草甸化小叶章湿地>沼泽化草甸小叶章湿地>沼泽化小叶章湿地;土壤细菌群落多样性之间差异显著(P<0.05),草甸小叶章湿地土壤微生物的Shannon-Wiener多样性指数和McIntosh指数最高,分别为3.30和64.03;沼泽化草甸小叶章湿地次之,分别为3.23和60.63;沼泽化小叶章湿地最低,分别为3.19和54.21.Shannon-Wiener多样性指数和McIntosh指数与平均颜色变化率变化规律一致,说明土壤细菌群落结构受到土壤理化性质的影响,并且随着土壤含水量的升高,土壤细菌群落的平均颜色变化率和多样性均呈下降趋势.土壤细菌群落对不同碳源的利用强度上存在明显差异,其中对碳水化合物类、氨基酸类碳源的利用强度差异不大(P>0.05),但是对羧酸类、胺类、酚酸类、多聚物类碳源的利用强度差异显著(P<0.05).主成分分析(PCA)表明,两个主成分累计贡献率为80%,能够很好地解释不同湿地土壤细菌在碳源利用上有明显的空间分异这一现象.碳水化合物类碳源对土壤细菌群落多样性的影响最高,其次是氨基酸类和羧酸类碳源.研究显示,土壤理化性质及植被群落组成是影响小叶章湿地土壤细菌群落组成和功能活性的重要因素.      

不同水分条件下小叶章湿地表土有机碳及活性有机碳组分季节动态

通过野外试验与室内分析,考察了三江平原生长季内不同水分条件小叶章(Calamagrostis anguatifolia)湿地表层0～20cm土壤有机碳(SOC)、轻组有机碳(LFOC)与微生物生物量碳(MBC)的季节变化动态.结果表明,不同水分条件小叶章湿地表土SOC及各组分含量季节变化明显.季节性积水条件对表土活性有...     

Nitrogen cycle of a typical Suaeda salsa marsh ecosystem in the Yellow River estuary

The nitrogen (N) biological cycle of the Suaeda salsa marsh ecosystem in the Yellow River estuary was studied during 2008 to 2009. Results showed that soil N had significant seasonal fluctuations and vertical distribution. The N/P ratio (15.73±1.77) of S. salsa was less than 16, indicating that plant growth was limited by both N and P. The N absorption coefficient of S. salsa was very low (0.007), while the N utilization and cycle coefficients were high (0.824 and 0.331, respectively). The N turnover among compartments of S. salsa marsh showed that N uptake from aboveground parts and roots were 2.539 and 0.622 g/m2, respectively. The N translocation from aboveground parts to roots and from roots to soil were 2.042 and 0.076 g/m2, respectively. The N translocation from aboveground living bodies to litter was 0.497 g/m2, the annual N return from litter to soil was far less than 0.368 g/m2, and the net N mineralization in topsoil during the growing season was 0.033 g/m2. N was an important limiting factor in S. salsa marsh, and the ecosystem was classified as unstable and vulnerable. S. salsa was seemingly well adapted to the low-nutrient status and vulnerable habitat, and the nutrient enrichment due to N import from the Yellow River estuary would be a potential threat to the S. salsa marsh. Excessive nutrient loading might favor invasive species and induce severe long-term degradation of the ecosystem if human intervention measures were not taken. The N quantitative relationships determined in our study might provide a scientific basis for the establishment of effective measures.     

三江平原典型湿地类型土壤微生物特征与土壤养分的研究

为探讨不同湿地类型土壤微生物数量和酶活性的分布特征及其与土壤养分的关系,本研究选择了三江平原洪河湿地保护区4种典型湿地类型(小叶章+沼柳湿地、小叶章湿地、毛苔草湿地和芦苇湿地)的土壤为研究对象.结果表明4种湿地类型在0~30 cm土层内:1土壤有机碳、全氮和全磷均随土层深度的增加而减少,速效钾、速效磷和速效氮则未表现出有规律的变化,且不同湿地类型土壤养分含量差异显著.2土壤微生物数量为细菌放线菌真菌,3种微生物菌落数量均随土层深度的增加而减少.土壤微生物总数量以小叶章湿地最多,毛苔草湿地最少.3土壤蔗糖酶和纤维素酶活性均随土层深度的增加而减少,而土壤过氧化氢酶活性未表现出有规律的变化.小叶章+沼柳湿地和小叶章湿地中3种酶活性显著性高于毛苔草湿地和芦苇湿地(P0.05).4相关性分析表明,土壤细菌、真菌和纤维素酶与土壤养分各指标均呈极显著或显著正相关,放线菌和蔗糖酶与速效钾、过氧化氢酶与速效钾、速效磷无显著相关性关系.因此,土壤微生物和酶活性是反映土壤养分状况的重要指标.