The impact of the accumulation of algal blooms on reed wetlands in the littoral zones of Chaohu Lake

In a large eutrophic lake,the littoral zone is normally an area with high-density elevated aquatic plant life,including algal blooms,where the presence of reed wetlands allows the accumulation of algae.In this study,the impact of accumulated algal blooms in reed wetlands in the littoral zone s of Chaohu Lake was investigated seasonally from 2018 to 2019.The concentrations of chlorophyll a(Chl a),total nitrogen(TN),and total phosphorus(TP)were much higher in the reed-covered littoral zones(RCLZ)than in the unvegetated littoral zones(ULZ),indicating that more algal biomass was trapped and accumulated in the RCLZ.Algal biomass could be horizontally transported to downwind littoral zones under low wind speeds,favoring the establishment of blooms.Algal accumulation levels were highest in summer due to high water temperatures and algal biomasses.Likewise,the northern littoral zones were conducive to the development of large algal blooms because of the wind pattern.The values of TN,TP,Chl a,and loss on ignition in surface sediments were higher in the RCLZ than in the ULZ.Moreover,the diffusive fluxes of ammonium and soluble reactive pho sphorus were also higher in the RCLZ than in the ULZ.Considering the capability of reed wetlands to trap algae,mechanical salvage and other physical methods should be adopted to eliminate algal biomass when massive blooms accumulate in the RCLZ.

Performance of a Horizontal Flow Constructed Reed Bed Filter for Municipal Wastewater Treatment: The Case Study of the Prototype Installed at Gaston Berger University, Saint-Louis, Senegal

In Saint-Louis, Senegal, a constructed wetland with horizontal flow reed beds (FHa and FHb) has demonstrated significant efficacy in treating municipal wastewater. Analyzing various treatment stages, the system showed only a slight temperature variation, from an influent average of 26.3°C to an effluent of 24.7°C. Electrical conductivity decreased from 1331 mS/cm to 974.5 mS/cm post-primary treatment, with suspended solids (SS) dramatically reduced from 718.9 mg/L to 5.7 mg/L in the final effluent. Biochemical oxygen demand (BOD5) and chemical oxygen demand (COD) saw a notable decrease, from initial levels of 655.6 mg/L and 1240 mg/L to 2.3 mg/L and 71.3 mg/L, respectively. Nitrogenous compounds (N-TN) and phosphates () also decreased significantly, indicating the system’s nutrient removal capacity. Microbiological analysis revealed a reduction in fecal coliforms from 7.5 Ulog/100ml to 1.8 Ulog/100ml and a complete elimination of helminth eggs. The presence of Phragmites and Typha was instrumental in enhancing these reductions. The system’s compliance with the Senegalese standards for disposal into natural environments, WHO recommendations for unrestricted water reuse in irrigation, and the European legislation for water reuse was established. The effluent quality met the stringent criteria for various classes of agricultural reuse, illustrating the system’s potential for sustainable water management. This wetland model presents a robust solution for water-stressed regions, ensuring environmental protection while supporting agricultural needs. The study calls for ongoing research to further refine the system for optimal, reliable wastewater treatment and water resource sustainability.

闽江河口湿地围垦稻田对土壤铁碳结合特征的影响

土壤铁氧化物结合态有机碳是有机碳长期维持的主要途径,但其机理研究仍较为薄弱。为探究河口湿地围垦稻田对土壤铁碳结合特征的影响,本研究选择福建省闽江河口天然芦苇湿地与围垦稻田为研究对象,对两种类型土壤中的铁结合态有机碳(Fe-OC)及其相关指标进行测定与分析。结果显示:①芦苇湿地围垦稻田改变了土壤氧化还原过程,显著影响土壤中铁相的转化。围垦后土壤二价铁[Fe(Ⅱ)]、三价铁[Fe(Ⅲ)]、活性总铁含量(HCl-Fe_(t))及Fe(Ⅲ)/Fe(Ⅱ)分别显著下降了24.68%、52.56%、51.45%、35.68%(P<0.05)。游离态氧化铁(Fe_(d))与无定形态铁(Fe_(o))含量分别显著下降了21.64%和29.24%(P<0.05),络合态铁(Fe_(p))含量则有所增加。②芦苇湿地围垦稻田显著影响土壤碳固存,Fe-OC与土壤有机碳含量(SOC)在围垦稻田后分别显著下降了39.03%和18.42%(P<0.05);芦苇湿地与稻田土壤Fe-OC均主要以吸附途径结合,稻田土壤Fe-OC对土壤有机碳的贡献率(fFe-OC)显著高于芦苇湿地(P<0.05)。③土壤全氮、含水量、电导率、铁以及土壤有机碳、溶解性有机碳与Fe-OC呈显著正相关(P<0.01)。本研究可为退耕还湿、土壤碳增汇提供科学参考。

太湖北部湖滨带芦苇湿地夏季水质时空变化特征分析

为了解太湖北部湖滨带芦苇湿地夏季水质时空变化,于2022年6—9月,在芦苇湿地时空分布调查的基础上,分别采集典型湖滨带芦苇湿地表层水体样品,测定pH、总氮(TN)、总磷(TP)、氨氮(NH+4-N)、高锰酸盐指数(COD Mn)、叶绿素a(Chl-a)等水质理化指标,并对湿地水质时空变化特征和水体富营养化状态进行分析。结果表明,所调查的7片芦苇湿地中pH、溶解氧(DO)、电导率(EC)、水温(WT)月间变化差异均极显著(p<0.01),COD Mn月间差异显著(p<0.05),但TN、TP、NH+4-N和Chl-a月间变化无显著差异(p>0.05)。所有水质理化指标在竺山湾、月亮湾、梅梁湾和贡湖湾芦苇湿地间均具有显著差异性(p<0.05)。湿地夏季水体基本呈中度或重度富营养化状态,时间上8月水质最差,地理位置上月亮湾最差。太湖北部湖滨带芦苇湿地水体属于磷限制型,限制磷元素的输入可有效控制湖滨带苇区水体富营养化的程度。

Effects of Environmental Conditions and Aboveground Biomass on CO2 Budget in Phragmites australis Wetland of Jiaozhou Bay,China

Estuarial saline wetlands have been recognized as a vital role in CO_2 cycling.However,insufficient attention has been paid to estimating CO_2 fluxes from estuarial saline wetlands.In this study,the static chamber-gas chromatography(GC) method was used to quantify CO_2 budget of an estuarial saline reed(Phragmites australis) wetland in Jiaozhou Bay in Qingdao City of Shandong Province,China during the reed growing season(May to October) in 2014.The CO_2 budget study involved net ecosystem CO_2 exchange(NEE),ecosystem respiration(Reco) and gross primary production(GPP).Temporal variation in CO_2 budget and the impact of air/soil temperature,illumination intensity and aboveground biomass exerted on CO_2 budget were analyzed.Results indicated that the wetland was acting as a net sink of 1129.16 g/m^2 during the entire growing season.Moreover,the values of Reco and GPP were 1744.89 g/m^2 and 2874.05 g/m^2,respectively;the ratio of Reco and GPP was 0.61.Diurnal and monthly patterns of CO_2 budget varied significantly during the study period.Reco showed exponential relationships with air temperature and soil temperature at 5 cm,10 cm,20 cm depths,and soil temperature at 5 cm depth was the most crucial influence factor among them.Meanwhile,temperature sensitivity(Q10) of Reco was negatively correlated with soil temperature.Light and temperature exerted strong controls over NEE and GPP.Aboveground biomass over the whole growing season showed non-linear relationships with CO_2 budget,while those during the early and peak growing season showed significant linear relationships with CO_2 budget.This research provides valuable reference for CO_2 exchange in estuarial saline wetland ecosystem.

盐碱湿地水溶性物质对冻融干扰的响应

以松嫩平原盐碱区查干湖湿地土壤为试材,采用模拟冻融培养的方法,研究不同冻融温度、冻融循环次数对土壤水溶性有机碳(WSOC)含量变化及水溶性物质荧光特性的影响,以期揭示盐碱湿地土壤水溶性物质对冻融循环和冻融温度的响应,为评价土壤肥力、资源的合理利用和土壤环境的修复提供参考依据。结果表明:湿地0~20 cm土层的土壤WSOC含量高于20~40 cm土层;冻融干扰对土壤水溶性有机碳含量有显著性影响;随着冻融循环次数的增加,土壤水溶性有机碳含量呈增加的趋势;冻融温度和冻融循环次数交互存在时影响土壤水溶性碳含量变化。不同冻融处理土壤WSOC均由类腐殖质酸组成,-25~5℃冻融温度样品中含有的腐殖酸含量最高;冻融处理影响了土壤水溶性物质的荧光强度,但并未影响土壤水溶性物质的结构变化。

Growth pattern of reed in Caogang Lake,Huanghuaihai Plain,China

The researches about reed growth were mainly concentrated on seasonal dynamics, investigation of reed resource, and comparison of different ecotypes of reed. By means of fractal geometric theory of non linear science, the fractal character of growth pattern of reed, for the purpose of quantitatively exploring the mechanism of reed growth was studied. The way to calculate fractal dimension of reed growth is box dimension (BD) and information dimension (ID). The results showed that the difference between two samplings in May and those among three samplings in June and later were not remarkable for both BD or ID. It was noted that the difference between samplings in and after May is significant. It was demonstrated that the fractal dimension of size distribution of reed ranged from 0 6235 to 0 8761 The distribution pattern could be statistically divided as two significant periods: the size of reed is quite well distributed at the beginning of reed growth (fractal dimension>0 8), but is irregular in the middle and later growth season (fractal dimension<0 7). These results are benefit to reach the goal of rational use of reed resources and to protect the biodiversity in wetland ecosystem.

Purification function of the natural wetland in the Liaohe Delta

The estuary wetland is the last barrier for inland pollutants flowing into the sea. The possibility to use the natural wetland, mainly reed marsh and Suaeda heteroptera community as land treatment system to polluted river water was studied. Experimental results indicated that the reed march has a high retention rate to pollutants like COD, N, P and oil. The canal system has high a purification rate to these elements as well. There is also a big potential to use the Suaeda community as a treatment system to exchange water from prawn and crab breeding ponds along the coast. As the pollution problem of coastal seawater has become more and more serious in Eastern China, and Liaohe is among the most seriously polluted 7 rivers in China, this study will greatly contribute to the strategy makers to take suitable reactions.

A Lab-scale Study on the Routes of Nitrogen and Phosphorus Removal in Gravel-based Reed Bed Systems

The removal of ammonia and phosphorus from an artificial wastewater was studied in two lab-scale reed beds.During batch and continuous operations,it was found that ammonia was removed from the wastewater via a two-step process,sorption inside bed matrices followed by nitrification into nitrite and nitrate.Rapid decrease in the concentration of ammonia in the artificial wastewater was observed during the batch operation,whereas during the continuous operation,which lasted for 39 days,the percentage removal of ammonia decreased gradually with time before stabilizing at around 20%.The efficiency of phosphorus removal exhausted rapidly during the continuous operation,from 39% on the first day of operation to virtually zero after only 5 days.The results suggest that sorption(which may include ion exchange,adsorption,and biomass assimilation) serves as an initial step to remove ammonia and phosphorus from the wastewater,prior to any microbial transformations.

Macroinvertebrate Assemblage Changes as an Indicator of Water Quality of Perennial Endorheic Reed Pans on the Mpumalanga Highveld, South Africa

Reed pans are a very uncommon type of endorheic wetland, and as such the amount of information available is very limited. Thus, they are being impacted on by various agricultural, livestock and other anthropogenic activities. The objectives of this study were to determine the spatial and temporal variations of macroinvertebrate community structures in reed pans and the environmental factors (i.e., water quality) responsible for the maintenance of these structures. Reed pans were studied over four different seasons, during which time subsurface water, sediment and macroinvertebrate samples were collected and analyzed. The reed pans studied showed that the macroinvertebrates were able to reflect various changes in reed pans with regard to seasonal variability and anthropogenic impacts on water quality. These anthropogenic impacts caused the disappearance of sensitive macroinvertebrate taxa and the increase of tolerant macroinvertebrate taxa.

基质改良对河岸带芦苇区冬季脱氮效果及土壤-植物化学计量特征的影响

为探究基质改良对亚热带地区河岸带芦苇区冬季脱氮效果和土壤-植物化学计量特征的影响,以河岸带土壤基质为对照,通过芦苇湿地模拟实验,系统探讨不同基质(砾石、砾石+生物炭、陶粒+生物炭、改性陶粒+生物炭)添加条件下,芦苇湿地的冬季脱氮效果,以及土壤和植物各器官中C、N、P含量及其化学计量比。结果表明:基质改良能够提高芦苇湿地冬季脱氮效果,添加砾石处理使NH_(4)^(+)-N去除率提高8.3个百分点(P<0.05),添加砾石+生物炭处理使TN和NH_(4)^(+)-N去除率均提高8.9个百分点(P<0.05)。基质改良能够增加土壤TC、TN和TP含量,其中,添加砾石+生物炭处理使三者含量均显著增加(P<0.05)。添加生物炭的3个处理均有利于根C固定和植物N吸收,添加陶粒+生物炭和改性陶粒+生物炭处理对植物生长具有促进作用。土壤-植物化学计量特征存在一定的相关性,且土壤与植物茎和根之间的关系更大;与植物相比,基质改良使芦苇湿地冬季脱氮效果更易受到土壤化学计量特征的影响。研究表明,适当的基质改良能够提高亚热带地区河岸带芦苇区冬季脱氮效果,增加土壤养分,促进植物生长。

The Design of Treatment Wetlands in the United Kingdom:Successes,Failures,and Alternative Approaches

Constructed wetland was first introduced into the United Kingdom in the middle of 1980s,following a visit by a group of scientist to Western Germany.In the past 2 decades,the applications of constructed wetlands in this country have expanded substantially,due to the demand for green technologies and rising cost of fossil fuel energies.This paper reported a statistical investigation of the performances of 78 horizontal flow wetlands,representatives of such system in the United Kingdom.Alternative design equations,based on organic matter removal efficiency,have been developed from Monod kinetics,and the accuracy and reliability of current and alternative design approaches have been examined.

Kinetic Modelling of the Removal of Seven Common Pollutants in Subsurface Flow Constructed Wetlands

The main removal mechanisms for the degradations of seven pollutants in wastewater treatment wetlands were analysed,and a mathematical model was established to quantify the removal of each pollutant,based on its main removal mechanisms.Subsurface horizontal flow wetlands were treated as a series of continuous stirred-tank reactors(CSTRs).Kinetic models for the removal of biochemical oxygen demand,chemical oxygen demand,ammonia,total nitrogen and faecal coliforms were established by combining Monod or first-order kinetics with CSTR assumptions.These tentative models account for a wide range of factors that affect wetland performance,but the models have not been proven by experiment data.Depending on the derivation of various coefficients in the models and verification by actual performance data,this study may provide a starting point for an integrated pollutant removal model to be developed,and experimentally verified,thereby making a step forward from the current greenbox'approach of wetland design.

2018-2020年盘锦芦苇湿地碳水通量数据集

湿地拥有巨大的碳汇能力、活跃的水汽交换和热量调节能力,是稳定温室气体排放、减缓气候变化的关键生态系统。辽河三角洲湿地是亚洲最大的暖温带滨海湿地,但湿地长期碳水通量的研究还比较欠缺,影响该地区CO_(2)通量和区域碳汇模拟精度,迫切需要对其进行长期的数据监测及整理。本数据集为辽河三角洲芦苇湿地生态系统2018–2020年通量观测数据,数据采集地位于中国气象局东北地区生态与农业气象野外科学试验基地盘锦芦苇湿地研究站。基于中国通量观测研究网络(ChinaFLUX)数据处理体系形成了标准化的生态系统碳水通量和关键气象要素数据集,数据集包括半小时、日、月和年4种尺度的数据文件。本数据集对准确评价辽河三角洲芦苇湿地生态系统碳水通量在区域和全球碳水循环中的地位和作用具有重要意义。

天津地区芦苇营养成分变化规律研究

为探索天津地区芦苇的营养成分变化规律,为芦苇饲料化利用奠定基础,试验采集天津主要芦苇产地不同生长时期的芦苇,并对其常规营养成分进行测定。结果表明:从展叶期到枯叶期,天津各地芦苇的粗蛋白质(CP)、粗灰分、钙(Ca)和磷(P)含量呈下降趋势;干物质(DM)和酸性洗涤木质素含量呈上升趋势;中性洗涤纤维(NDF)和酸性洗涤纤维呈降低—升高的趋势;总能(GE)和粗脂肪(EE)含量呈下降—升高—下降的趋势。抽穗期芦苇的DM含量、CP含量、NDF含量、Ca含量和P含量与生长后期无显著性差异(P>0.05),EE含量和GE含量与开花期无显著性差异(P>0.05),且达到最高水平。综合芦苇的营养价值和适口性等因素分析,抽穗期芦苇饲料化开发利用的潜力最大。

三种湿地植物产沼气潜力及特性研究

为了探究湿地植物沼气发酵的可行性以及产气的相关特性,以芦苇(Phragmites australis)、睡莲(Nymphaea thermarum)和菖蒲(Acorus calamus)为发酵原料,采用批量式工艺,在35℃恒温水浴条件下进行沼气发酵实验。结果显示,这三种湿地植物产沼气潜力分别是:芦苇为3297 mL/g(VS),睡莲为1385 mL/g(VS),菖蒲为1516 mL/g(VS),它们的产气量分别在第25 d、10 d和10 d达到总产气量的80%以上,平均甲烷体积分数为57%、60%和58%。与其他植物发酵原料的产气潜力对比分析的情况显示,芦苇、睡莲和菖蒲可以作为沼气发酵原料。

自由表面流人工湿地处理超稠油废水

采用自由表面流芦苇湿地处理超稠油废水 .当芦苇床的水力负荷为 3 3 3cm/d时 ,对于年平均进水COD4 59.1 6mg/L ,石油类 2 7 65mg/L ,BOD53 3 52mg/L ,TN 1 3 74mg/L的超稠油废水 ,该系统的出水指标为COD77 2 1mg/L ,石油类 1 4 2mg/L ,BOD53 90mg/L ,TN 1 60mg/L .去除率分别为 :COD 83 1 8% ,石油类 94 86% ,BOD588 3 7% ,TN 88 3 6% ,pH值由 7 87降至 7.77.处理后的超稠油废水对土壤的污染并不明显 ,对芦苇的生长和材质指标几乎没有影响 .可见 ,自由表面流芦苇湿地深度处理超稠油废水的出水水质稳定 ,耐冲击负荷强 。

芦苇湿地生态系统对造纸废水中铅的净化研究

采集辽宁双台河口芦苇湿地芦苇样品,于沈阳农业大学实验场的试验池内进行了对废水中Pb净化的模拟试验.分析了芦苇生长季内,造纸废水、湿地土壤和芦苇组织中的Pb分布特征.结果表明,芦苇灌溉20%浓度的造纸废水,对Pb的去除率最高;芦苇在拔节期阶段,去除效果最好.对于同一生长期,在10cm水深处Pb的含量最少,净化效果最明显;在10～40cm深度土壤对Pb的热力学吸附差异显著.随着采样深度的增加,土壤在10cm深处对Pb的吸附量最大,净化效果最明显.芦苇组织中Pb的分布特征为,在芦苇整个生长期内,芦苇根组织对Pb的吸收量最大,其次为茎组织,而叶组织对Pb的吸收量最小.

黄河三角洲芦苇湿地生态系统碳、水热通量特征

利用涡度相关法对黄河三角洲芦苇湿地生态系统进行了连续两年的通量观测,对2009—2010年生长季芦苇湿地的净生态系统碳交换量(NEE),感热通量(Hs)和潜热通量(LE)数据进行了分析。结果表明,在日尺度上,芦苇湿地NEE日变化特征表现为两个CO2吸收高峰,分别出现在11:00和16:00左右,其特点是在午间出现了碳交换通量的降低。CO2吸收的日最大值在两个生长季出现的时间有所不同,分别出现在2009年7月(-0.30 mg CO2m-2s-1)和2010年6月(-0.37 mg CO2m-2s-1)。CO2排放的日最大值两个生长季均出现在9月,分别为0.19和0.25 mg CO2m-2s-1。Hs和LE的日动态均为单峰型,极值都出现在中午前后,生长季生态系统的能量消耗主要以潜热为主,且在日尺度上,热通量和NEE有显著的负相关关系。在季节尺度上,芦苇湿地生长季具有明显的碳汇功能,2009年生长季生态系统白天固定354.63 g CO2/m2,同时期夜间释放159.24 g CO2/m2,净CO2吸收量为-195.39 g CO2/m2。2009年整个生长季生态系统总初级生产力(GPP)为-651.13 g CO2/m2,生态系统呼吸(Re)为455.74 g CO2/m2,系统表现为碳汇。路径分析表明:光合有效辐射(PAR)显著影响NEE的日动态(R2=0.46—0.84),而NEE的季节动态主要受土壤温度的影响,降水和PAR的影响次之。

基于MODIS数据的松嫩平原西部芦苇湿地地上生物量遥感估算

芦苇作为湿地生态系统中重要的群落类型,其地上生物量是衡量湿地生态系统质量的关键指标。应用面向对象的土地覆盖分类技术,基于多季相Landsat8 OLI遥感数据,提取松嫩平原西部芦苇湿地分布信息;依托野外实测芦苇地上生物量数据(AGB)和同期MODIS数据源的NDVI、EVI、RVI、MSAVI和WDVI 5种光谱植被指数,探讨不同光谱植被指数对芦苇AGB的敏感性,进而构建松嫩平原西部芦苇AGB遥感估算最优模型,并进行芦苇AGB遥感反演及空间格局分析。结果表明:2014年松嫩平原西部地区芦苇总面积为1653 km^2,其中扎龙湿地自然保护区内芦苇分布面积最大(1178km^2),占区域芦苇总面积的71.3%;所选取的5种植被指数均与芦苇AGB呈极显著正相关(P<0.01),基于EVI构建的指数曲线模型为松嫩平原西部芦苇AGB反演的最优模型(R2=0.55)。研究区芦苇平均AGB为372.1g/m^2,AGB总量为6.14×105t,其中扎龙湿地自然保护区内芦苇AGB总量为4.38×105t;各保护区芦苇平均AGB由大到小依次为:向海保护区(469.7 g/m^2)>大布苏保护区(454.1 g/m^2)>莫莫格保护区(373.0 g/m^2)>扎龙保护区(372.4 g/m^2)>查干湖保护区(369.8 g/m^2);松嫩平原西部芦苇AGB总体呈现南高北低的分布格局,将为湿地生态系统管理与保护及芦苇资源的合理利用提供科学依据。