盐分对河口淡水、微咸水沼泽湿地土壤甲烷产生潜力的影响

海平面上升导致河口区盐水入侵现象日益明显,深刻影响着河口潮汐淡水、微咸水湿地生物地球化学循环。采集闽江河口区淡水、微咸水短叶茳芏潮汐沼泽湿地表层土样,室内添加盐度为5,10,15,21 g/L的人造海水、Na Cl溶液及盐度为0的去离子水,通过室内泥浆厌氧培养试验,对比研究海水和Na Cl溶液对淡水、微咸水沼泽湿地土壤甲烷产生潜力的影响。与对照相比,1—12 d培养期内4个盐度的海水处理均显著抑制河口淡水、微咸水沼泽湿地甲烷产生潜力,抑制率在93%以上,盐度10—21 g/L的3个海水处理对于河口淡水、微咸水沼泽湿地甲烷产生潜力的抑制效应无显著差异。Na Cl溶液只有在盐度达到15和21 g/L才显著抑制淡水、微咸水沼泽湿地甲烷产生潜力,且抑制率最多为80.9%,盐度为5、10 g/L的Na Cl溶液对淡水、微咸水沼泽湿地甲烷产生潜力的抑制作用不显著,抑制率多小于30%。伴随着盐水入侵而发生的硫酸盐还原作用及离子胁迫作用对河口淡水、微咸水沼泽湿地甲烷产生具有显著的抑制效应。

三江平原土地利用变化对水体中铁环境行为的影响

三江平原湿地农田化对铁的赋存形态、迁移转化特征及输出量产生影响。以湿地沼泽水体和稻田水体为研究对象,利用切向超滤技术分离铁的形态,研究土地利用变化前后铁的形态、迁移转化特征的差异。结果表明:湿地农田化后水体中可溶态总铁质量浓度下降16.9%;由于水体pH值的升高,Fe2+质量浓度下降56.3%,非溶解态酸性不稳定铁含量显著升高。沼泽水和稻田水在迁移过程中,铁均以络合态铁和酸性不稳定态铁2种形态迁移。沼泽水在迁移过程中Fe2+和络合态铁含量下降,酸性不稳定态铁含量升高,胶体态铁含量变化不大;稻田水在迁移过程中,络合态铁和酸性不稳定态铁含量下降,Fe2+和胶体态铁含量较稳定。2种水体铁形态的转化有较大差异:日间沼泽水中非溶解态的酸性不稳定态铁向可溶态铁转化;稻田水体可溶态铁向酸性不稳定态铁转化。

泥炭沼泽学若干基本概念的再认识

综合国内外有关研究成果,比较和区别了泥炭沼泽学的若干基本概念.泥炭沼泽是自然或人为干扰较少的积累泥炭的生态系统,而泥炭地则可以有较强人为干扰.雨养泥炭沼泽营养补给主要源于大气降水,矿养泥炭沼泽则主要接受地表水和地下水补给.部分木本植物沼泽和挺水植物沼泽属于泥炭沼泽的范畴,但在北半球,挺水植物沼泽并非主要的积累泥炭的湿地类型.低、中和高位泥炭沼泽是针对泥炭沼泽的地貌形态而言的,不应与泥炭沼泽的发育阶段建立普遍而严格的联系.富、中和贫营养泥炭沼泽概念的使用应慎重,只有通过水化学测试才能准确确定泥炭沼泽的营养状况.同时浅析了造成泥炭沼泽学中若干概念混淆或误解的主要原因.

若尔盖湿地各类水体的水化学与同位素特征及其补给关系分析

为了探究若尔盖湿地的水环境特征及水体补给关系,于2019年、2020年和2021年夏季,采集大气降水、黑河干支流河水、沼泽水和地下水样品,分析不同水体水化学及氢氧稳定同位素特征,并利用端元混合模型,估算不同水体间的补给比例。研究结果表明,大气降水是各水体的最初补给源,黑河干流中下游和西北部地下水受大气降水影响较大;黑河干流中上游受南部沼泽、南部黑河支流和降水的补给比例分别为68.52%、22.76%和8.72%;北部出湖的黑河支流受北部沼泽和降水的补给比例分别为62.88%和37.12%;东南部地下水受北部入湖黑河支流和黑河干流中上游的补给比例分别为67.88%和32.12%,西北部地下水受黑河干流中下游和南部沼泽的补给比例分别为88.59%和11.41%。

固相萃取-高效液相色谱法同时测定泥炭沼泽源水体中9种酚类物质

建立了固相萃取-高效液相色谱同时分析测定泥炭沼泽区水体中原儿茶酸、对羟基苯甲酸、香草酸、龙胆酸、咖啡酸、阿魏酸、水杨酸、对香豆酸(trans-4-Hydroxycinnamic acid)、丁香酸等9种酚类的方法。沼泽区水体采用MEGA Bond Elut Plexa固相萃取柱富集后,在含5 g/L乙酸的V(甲醇):V(水)=5:95流动相中用Agilent ZORBAX SB-Aq色谱柱(250 mm×4.6 mm,5μm)分离,外标法定量。结果表明,9种酚类物质在0.1～60 mg/L范围内均呈良好的线性关系,线性相关系数均大于0.9987,仪器检出限0.07～0.37 mg/L。空白水中的加标回收率为90.4%～106.8%,相对标准偏差(n=6)为1.9%～6.2%。应用该方法测定了若尔盖泥炭沼泽区水体样品,9种酚酸均检出。

养分浓度和光照强度对泥炭藓有性更新的影响

作为优势植物,泥炭藓(Sphagnum)在泥炭沼泽中缺乏有性更新的原因尚不清楚。针对影响孢子萌发的光强和养分条件,以泥炭藓(S.palustre)为材料,通过室内孢子萌发实验,研究不同光强和养分浓度对孢子萌发率、萌发势及萌发指数的影响。4种培养基中,养分浓度高的营养液培养基中孢子萌发率最高,达到60%,其次为养分浓度与营养液相近的琼脂+营养液培养基,萌发率为48%,再次为养分水平很低的沼泽水培养基,萌发率约为30%,几乎无养分的蒸馏水培养基中萌发率最低,约为5%。萌发势和萌发指数亦呈现相同的规律。琼脂+营养液和营养液培养基较沼泽水和蒸馏水培养基孢子萌发时间提前约3天时间。增加光强使孢子萌发率仅提高10%。研究表明,低养分浓度和弱光照均不利于孢子萌发,相对而言,泥炭沼泽的贫营养特征应是限制泥炭藓有性更新的更重要因素。

河口区淡水和微咸水潮汐沼泽湿地沉积物反硝化作用

为探讨河口区淡水和微咸水潮汐沼泽湿地沉积物反硝化作用及影响因素,以分布在闽江口道庆洲上的短叶茳芏(Cyperus malaccensis)淡水沼泽湿地和鳝鱼滩上的短叶茳芏微咸水沼泽湿地沉积物为研究对象,运用乙炔抑制培养法测定不同季节的反硝化速率,同时测定沉积物和上覆水理化性质.结果发现,2个短叶茳芏沼泽湿地沉积物反硝化速率均存在明显的季节变化,最高(最低)值分别出现在夏季(秋季)和春季(冬季),温度是影响反硝化速率季节变化的重要因素.道庆洲沉积物反硝化速率((32.72±19.15)μmol·m^(-2)·h^(-1),以N计,下同)显著高于鳝鱼滩((4.97±2.64)μmol·m^(-2)·h^(-1))(p<0.05).沉积物电导率和上覆水SO_4^(2-)含量对河口区潮汐沼泽湿地沉积物反硝化速率具有抑制作用,是造成微咸水沼泽湿地沉积物反硝化速率显著低于淡水沼泽湿地的重要因素.沉积物电导率主要通过抑制沉积物对NH_4^+-N的吸收影响硝化-反硝化耦合作用,进而影响反硝化速率.淡水沼泽湿地反硝化速率对SO_4^(2-)作用的响应较微咸水沼泽湿地更为敏感.

河南禹县煤矿区煤质特征与成煤环境的关系

咸水、半咸水及淡水成煤环境中形成的煤层,其硫含量变化趋势由高向低.灰成分的比值则由小至大.同一煤层中的硫含量变化与成煤沼泽的覆水深度呈正相关.煤层灰分的高低与成煤沼泽中的陆源碎屑的供应及沼泽水体的流通扩散状态有关.同一煤层中的灰分含量高低与成煤沼泽古地貌关系密切,反映了风携沉积物对煤中灰分的影响.

DNA Damage and Repair of Two Ecotypes of Phragmites communis Subjected to Water Stress

In order to thoroughly understand the mechanism Of drought resistance in plants at DNA level, the DNA damage of two ecotypes of reeds (Phragmites communis T.) stressed by PEG 6000 was analyzed by means of fluorescence analysis of DNA unwinding (FADU). The results showed that the residual double strand DNA percentages (dsDNA%) in dune reed (DR) were significantly higher than those in swamp reed (SR) treated with either 20% or 30% PEG 6000. This meant that the DNA of DR was less damaged in comparison with SR. Similarly, DR resisted DNA damage more strongly than SR as reactive oxygen species (ROS) increased by adding ROS producers diethyldithio carbamate (DDC), H2O2 and Fe2+ of different concentrations. Meanwhile, treating PEG stressed SR with ROS scavengers such as dimethyl sulphoxide (DMSO) and ascorbic acid (Vc) resulted in the reduction of DNA damage, suggesting that ROS could cause DNA damage. In addition, the DNA repair for water-stressed reeds indicated that DR repaired DNA damage much faster and more completely. This might be the first indication that drought stress led to DNA damage in plants and that drought resistance of plants was closely related to DNA damage and repair.

河渚塔与“杭铁头”绰号流传

杭州西湖边有众多古塔楼阁,为湖光山林增色不少。古代,西溪也有一座宝塔,称之河渚塔。此塔突兀于芦海之上,村民进出湿地大多撑船,沼泽水道迷茫曲折,此塔也就成了船民的指针。每到暮秋,风起云涌之时,便会泛起阵阵芦浪,滚滚而来,此塔顶风而立,犹如中流砥柱,景色煞是壮观。历代以来,河渚塔便成了西溪旅游的座标。

亲历秘境──首次穿越雅鲁藏布大峡谷

公元１９９４年４月，中国科学家证论了雅鲁藏布大峡谷是世界上最深最长、海拔最高的峡谷。从此，过去曾先后被称为世界第一大峡谷的深达２１３３米的美国科罗拉多大峡谷、深达３２００米的秘鲁科尔卡大峡谷则退居次要地位。１９９８年１０月，雅鲁藏布大峡谷被国务院正式批准定名。 １９９８年１０月，中国科学探险考察队徒步考察雅鲁藏布大峡谷活动正式启动。因大峡谷地区情况复杂多变，探险计划多次调整，最后分四队展开工作。 本文作者李清波被分在第一分队。第一分队由派区出发，经白马狗熊，翻越西兴拉雪山，发现了藏布巴东大瀑布，找到大峡谷地质变化的矿石标本，之后直奔扎曲大本营会合。 下文便是作者翻越西兴拉雷山前后的一段经历与感受……

Phosphorus Concentration and Forms in Surface and Subsurface Drainage Water from Wetland Rice Fields in the Shaoxing Plain

Phosphorus (P) is the limiting factor for eutrophication in most freshwater ecosystems. In China, Ptransported from intensively cultivated land has been reported as an important source of P in surface waters.In this study, we investigated P concentration and forms in surface and subsurface drainage from wetland ricefields in the Shaoxing plain, Zhejiang Province, China. From selected rice fields, surface drainage sampleswere collected at rice-growing, non-growing and fertilization periods, and subsurface drainage samples atdrought and rewetting (irrigation or precipitation after 5～10 d drought period in the surface soils) and wet(drainage under long-term wet soil condition) periods. Water samples were characterized for their totalreactive P (TRP), dissolved reactive P (DRP) and particulate reactive P (PRP). Concentrations of the TRPand DRP in the surface drainage ranged from 0.08 to 1.50 and 0.06 to 1.27 mg L-1, respectively. The TRPand DRP were dependent on field operation activities, and decreased in the order of fertilization period ＞rice-growing period ＞ non-growing period. Phosphorus concentration of runoff receiving P fertilizer can bean environmental concern. The PRP concentration in the surface drainage, ranging from 0.01 to 0.57 mgL-1, accounted for 8%～78% of the TRP. Concentration of the TRP in the subsurface drainage was from0.026 to 0.090 mg L-1, consisting of 29%～90 % of the DRP and 10%～71% of the PRP. In the droughtand rewetting period, the PRP accounted for, on average, 63% of the TRP, much higher than in the wetperiod (23%), suggesting that there was transport of P in preferential flow during drainage events after ashort-term drought period in the surface soils. Therefore, P losses in particulate form may be importantin the subsurface drainage from rice fields when surface soils form cracks and favor rapid flow downwardthrough the soil profiles, suggesting the important role of water-dispersible colloid particles in mediating andco-transporting P in the subsurface drainage of rice fields.

THE EFFECT OF DRAINAGE ON CHEMICALELEMENTS CONTENT OF MARSH

This paper takes marsh in the Sanjiang Plain as an example in order to research the effect of draining on the chemical elements in marsh. The Sanjiang Ecological Test Station of Mire and Uetland serves as the resarch base. The authors selected soil samples in the Sanjiang Plain (the top and the end of the drain, marsh soil and degeneration marsh soil), mainly analyzed contents of main ions (HCO 3 ? , Cl?, SO 4 2? and NO 3 ? ), main heavy metals (Fe, Mn, Zn and Cu), nutritive elements (N, P, K), organic matter and pH value. By testing these samples as above, the paper initially researches the effect on chemical elements content by draining by the means of the contrast of chemical elements contents between marsh soil and degenerative marsh soil and different characteristics of marsh soil elements. Results show that a lot of chemical elements had been lost because of draining.

Effects of Anthropogenic Disturbance on Sediment Organic Carbon Mineralization Under Different Water Conditions in Coastal Wetland of a Subtropical Estuary

The changes in soil organic carbon(C) mineralization as affected by anthropogenic disturbance directly determine the role of soils as C source or sink in the global C budget. The objectives of this study were to investigate the effects of anthropogenic disturbance(aquaculture pond, pollutant discharge and agricultural activity) on soil organic C mineralization under different water conditions in the Minjiang River estuary wetland, Southeast China. The results showed that the organic C mineralization in the wetland soils was significantly affected by human disturbance and water conditions(P < 0.001), and the interaction between human disturbance activities and water conditions was also significant(P < 0.01). The C mineralization rate and the cumulative mineralized carbon dioxide-carbon(CO_2-C)(at the 49th day) ranked from highest to lowest as follows: Phragmites australis wetland soil > aquaculture pond sediment > soil near the discharge outlet > rice paddy soil. This indicated that human disturbance inhibited the mineralization of C in soils of the Minjiang River estuary wetland, and the inhibition increased with the intensity of human disturbance. The data for cumulative mineralized CO_2-C showed a good fit(R^2 > 0.91) to the first-order kinetic model C_t = C_0(1 – exp(–kt)). The kinetic parameters C_0, k and C_0 k were significantly affected by human disturbance and water conditions. In addition, the total amount of mineralized C(in 49 d) was positively related to C_0, C_0 k and electrical conductivity of soils. These findings indicated that anthropogenic disturbance suppressed the organic C mineralization potential in subtropical coastal wetland soils, and changes of water pattern as affected by human activities in the future would have a strong influence on C cycling in the subtropical estuarine wetlands.

Stem flow chemistry of Picea glehnii,Abies sachalinensis and Alnus japonica and its effect on the peat pore water chemistry in an ombrogenous mire in Ochiishi,eastern Hokkaido,Japan

We investigated the chemical properties of stemflow of Picea glehnii,Abies sachalinensis and Alnus japonica as well as peat pore water chemistry,including the distance and depth profiles of pore water chemistry,in an ombrogenous mire.The effect of stemflow on the peat pore water chemistry was clear at the stem base in the peat forest in the mire,and the peat pore water around the stem base of a tree had its own chemical properties specific to each species.P.glehnii showed the highest concentration of salts both in stemflow and peat-pore water,whereas A.japonica showed the lowest concentrations;however,the gradient of the chemical environment from the stem base to outside of the canopy is formed.The peat pore water chemistry under the canopy was mainly controlled by the chemical processes diluted by the abundant peat pore water;the stemflow movement in the high water content of the peat was more slowly because of the flat topography（〈 1o）.This would be due to the fact that the chemicals in stemflow would be diluted by the abundant peat pore water.The spatial heterogeneity of chemical environment between microsites within forested peatland would be also contributed indirectly through the control of microorganism activity,and nutrient regeneration mediated the surface water and the stemflow of the dominant canopy trees.

Indication of Bacteria in Water Marshes （Southern Iraq）

The study was conducted in water marshes for five major marshes during the months of January, April and September of each region （Hawizeh, Hammer and the central marsh） in southern Iraq. Bacteriological analysis that some of the default pathological bacteria, including TC （Total bacterial count）, FCB （faecal coliform bacteria）, MPN （coliform bacteria） and FS （faecal streptococcus） can evidence to indicate of pollution. The results showed that most of the water samples examined pathological contain bacteria which indicates that the water is unfit for human consumption and the waters as basal （more hydrogen than No. 7）. There was a high salinity more than the permissible limits for human consumption and even to irrigate crops, and the same case for dissolve oxygen which exceeded are other limits as drinking water.

Effects of Nitrogen Additions on Soil Seed Banks of a Freshwater Marsh in Sanjiang Plain, Northeast China

Over the past five decades, the natural wetlands in Sanjiang Plain, Northeast China, have been extensively reclaimed for agriculture with a total loss of nearly 80% of the surface area and the undrained marshes have received a large amount of exogenous nitrogen （N） input from the adjacent agricultural land because of fertilization. In the present study, the effects of nitrogen additions on seed germination and seedling biomass of Calamagrostis angustifolia in freshwater marsh were tested in a greenhouse study. Seed bank soil was exposed to different N additions （0, 5, 10, 20 and 40 g/m^2） under non-flooded water regime. Results revealed that, low level of N additions （less than 10 g/m^2） did not significantly affect the species richness and seedling density, while the seedling biomass at 5 g/m^2 of N addition was higher than other nutrient conditions. But species richness, seedling emergence and biomass decreased significantly at high level of N additions （20-40 g/m^2）. The responses were species-specific. High level of N additions had negative impacts on seed germination, seedling growth and biomass of dominant species Eleocharis ovata, Calamagrostis angustifolia, duncus effusus in the seed bank. To protect and restore the wetland vegetation community in the Sanjiang plain, fertilization, irrigation and land management strategies will need to be implemented to reduce the nutrient input from the agricultural land to the wetlands.

Seasonal and Spatial Variability of Water Quality and Nutrient Removal Efficiency of Restored Wetland： A Case Study in Fujin National Wetland Park, China

To investigate the spatio-temporal and compositional variation of selected water quality parameters and understand the puri- fying effects of wetland in Fujin National Wetland Park （FNWP）, China, the trophic level index （TLI）, paired samples t-test and correla- tion analysis were used for the statistical analysis of a set of 10 water quality parameters. The analyses were based on water samples collected from 22 stations in FNWP between 2014 and 2016. Results initially reveal that total nitrogen （TN） concentrations are above class V levels （2 mg/L）, total phosphorus （TP） concentrations are below class III levels （0.2 mg/L）, and that all other parameters fall within standard ranges. Highest values for TN, pH, and Chlorophyll-a were recorded in 2016, while the levels of chemical oxygen de- mand （CODMn） and biochemical oxygen demand （BODs） were lowest during this year. Similarly, TN values were highest between 2014 and 2016 while dissolved oxygen （DO） concentrations were lowest in the summer and TP concentrations were highest in the autumn. Significant variations were also found in Secchi depth （SD）, TN, CODMn （P 〈 0.01）, TP, and DO levels （P 〈 0.05） between the inlet and outlet of the park. High-to-low levels of TN, TP, and TDS were found in cattails, reeds, and open water （the opposite trend was seen in SD levels）. Tested wetland water had a light eutrophication status in most cases and TN and TP removal rates were between 7.54%-84.36% and 37.50%-70.83%, respectively. Data also show no significant annual changes in water quality within this wetland, although obvious affects from surrounding agricultural drainage were nevertheless recorded. Results reveal a high major nutrient removal efficiency （N and P）. The upper limits of these phenomena should be addressed in future research alongside a more efficient and scientific agricultural layout for the regions in and around the FNWP.

天津七里海湿地水体的同位素和水化学特征

为了研究天津七里海湿地水体及其周边水体的水化学和同位素特征,2015年8月10~12日和12月5~7日采集了湿地内的沼泽水、潮白新河水、永定新河水和周边地下水水样,分析水样的稳定氢、氧同位素和水化学组成。结果表明,无论是在8月采样日还是在12月采样日,沼泽水的电导率都比附近的河水高;河水和沼泽水的水化学类型为Na-Cl,地下水的水化学类型为Na-HCO_3。天津七里海湿地的沼泽水和河水的水化学组成主要受控于蒸发结晶作用和人类活动,而地下水中的离子含量与岩石风化有关。8月采样日和12月采样日,沼泽水和河水的同位素组成富集,存在明显的变化;地下水的同位素组成贫化,年内变化小。潮白新河附近的沼泽水同位素组成与河水接近。沼泽水在8月采样日受到强烈的蒸发作用,其过量氘值小于12月采样日。潮白新河上的水闸对河水的同位素和水化学有直接影响,进而影响湿地水质。此外,在高含盐量的土壤环境下,七里海湿地的沼泽水中Na^+和Cl^-含量增加,可能导致水体盐分积累。