模拟升温对沉水植物生长及磷迁移的影响

通过构建2组人工配置沉水植物群落,以增温5℃增温组模拟微宇宙环境暖化,通过沉水植物的存活率、相对生长速率、优势度、多样性指数等来研究暖化对沉水植物生长及物种多样性的影响;同时通过上覆水各形态磷、沉积物各形态磷的测定来研究气候暖化条件下2种人工配置沉水植物群落对磷迁移的影响。研究表明,极端高温不利于人工配置Ⅱ(金鱼藻占60%,黑藻和菹草各占20%)的生长,但秋冬季暖化可延长沉水植物的生长期,总体来看其相对生长速率、存活率未受影响。气候暖化降低了物种多样性,不利于沉水植物群落稳定。对于磷迁移,钙磷(Ca-P)在增温条件下高于未增温条件下。     

盐胁迫对3种沉水植物生物学指标及叶片中丙二醛含量的影响

以沉水植物苦草、轮叶黑藻、狐尾藻为研究对象,分别研究了在不同盐度下3种沉水植物的生物学指标和生理状况,以期为沿海地区水系沉水植物构建提供依据。结果表明,在0.05mol/L盐度下轮叶黑藻、苦草出现生长抑制,株高、鲜质量下降,叶片中丙二醛含量增加,单株叶片面积减小,而狐尾藻在0.05mol/L盐度下生长良好,0.08mol/L盐度下出现株高、鲜质量下降,叶片中丙二醛含量增高的现象。因此,推荐盐度在0.05mol/L以下的水体,可以建植苦草和轮叶黑藻,盐度不高于0.08mol/L的水体可以建植狐尾藻。盐胁迫下沉水植物会表现为一定的抗逆性,会通过单株叶片面积减小、增加根冠比、叶片肉质化等措施来减少水分流失和保证机体的正常生理功能,但超过一定的阀值,抗逆性会减弱,导致沉水植物出现生长抑制或者死亡现象。在有一定盐度的水体进行沉水植物建植恢复,该沉水植物能够耐受的盐度高于水体的盐度,是保证沉水植物成活的基本前提。     

草海底泥原位钝化工程示范及其生态环境效应

选取贵州草海重污染湖区,利用改性粘土钝化剂开展底泥原位钝化技术示范,对示范区内外主要水质参数、浮游生物和底栖动物等进行了对比监测与研究。结果表明:示范工程实施一年后钝化区水体氨氮(NH_3-N)和总磷(TP)含量分别降低至对照区的29%和23%,水体溶解氧含量达9 mg·L~(-1)以上,透明度显著增加;钝化区水体藻类总丰度降低40%以上,蓝藻所占比例大幅下降;钝化区沉水植物生长繁茂,水体自净功能明显增强,已形成草型清水生态系统。钝化区与对照区水体浮游动物、底栖水生生物种群及丰度无显著变化,表明钝化剂未对动物生长造成不良影响;原位钝化技术具有快速提升水体透明度和溶解氧含量、抑制底泥污染物释放、降低水体营养盐含量及抑制藻类生长等特点,且实施方便、成本低廉,在湖泊底泥污染治理和水体富营养化防治领域具有广阔应用前景。     

模拟水生生态系统中沉水植物对水体营养物质消减的影响

研究了模拟水生生态系统中沉水植物对水体营养物质消减的影响.在水体、底泥和沉水植物所组成的模拟生态系统中,沉水植物的生长对于水体中的营养盐浓度具有显著影响.沉水植物对水体营养盐浓度的影响通过多种途径实现,比如直接吸收、促进沉降吸附和促进硝化反硝化作用等.沉水植物的存在降低了模拟水生生态系统中水体营养盐的平衡浓度,同时温度对营养盐的归趋也有重要影响,温度的降低会减缓营养盐从水体中的去除,而温度升高,则会加速这一过程.     

沉水植物与2种不同辅料混合好氧堆肥

沉水植物富含氮、磷和钾等营养元素,通过堆肥实现营养物质的回收和利用是沉水植物资源化的有效途径。但是沉水植物含水率高、碳氮比低,需要对其进行一定的优化才能实现更好的堆肥效果。本研究采用麦秸、树叶分别作为辅料和沉水植物进行混合好氧堆肥实验,沉水植物好氧堆肥作为控制组。通过测定温度、挥发分、耗氧速率、电导率、种子发芽率(GI)、总氮、总磷和总钾等以评价堆肥产品的腐熟度和养分。结果表明,沉水植物好氧堆肥具有一定可行性,堆肥产品总养分含量为6.01%,符合有机肥使用标准(NY525-2012)中对总养分的要求,具有较好腐熟度,但堆肥产品pH值为8.90,大于标准值8.50,氮素损失率为35.11%;通过分别添加麦秸、树叶与沉水植物混合堆肥,堆肥产品pH值分别为8.33和8.24,氮素损失率分别为20.25%和11.21%;由电导率、GI、碳氮比综合分析3组堆肥产品腐熟度从高到低顺序为沉水植物与树叶沉水植物与麦秸沉水植物。通过添加富碳辅料如麦秸、树叶与沉水植物混合堆肥可以提高堆肥产品腐熟度,减少氮素损失提高肥效。     

利用多源遥感数据预警太湖沉水植物与藻类水华过程的实例研究

综合利用多源遥感数据完成1次太湖沉水植物与藻类水华预警。首先,利用时间分辨率较高的中分辨率成像光谱仪(MODIS)数据(空间分辨率250m,每天过境4次)进行连续监测,发现太湖宜兴西部沿岸与竺山湖水域交界处有连续多日的稳定蓝藻聚集区域,然后利用空间分辨率较高的环境一号卫星电荷耦合元件传感器(CCD)数据(空间分辨率30m,每3天过境2次)结合实地观测对蓝藻聚集原因进行分析,得出此次蓝藻富集是由高密度沉水植物的阻隔作用导致,并对沉水植物区域进行了提取与面积统计。研究结果验证了利用多源遥感数据进行沉水植物与藻类水华预警的可行性和便捷性,所采用的技术方法可以为相关研究和监测提供借鉴。     

5种湿地沉水植物对模拟污水厂尾水的深度处理

选取四季常青苦草、普通苦草、黑藻、狐尾藻和马来眼子菜等5种沉水植物构建表面流人工湿地系统,观察不同沉水植物品种对模拟污水厂尾水中主要污染物的去除效果,筛选出具有最佳去污效果的沉水植物,为优化沉水植物表面流人工湿地系统的处理效果提供理论依据。结果表明:沉水植物表面流湿地系统和无植物表面流湿地系统对各污染物的去除效果均呈现出随着实验时间的延长先波动变化后逐渐趋于稳定的规律。四季常青苦草、黑藻和狐尾藻湿地系统出水COD、TP浓度均低于10 mg·L~(-1)、0.1 mg·L~(-1),分别达到了《地表水环境质量标准》(GB 3838~(-2)002)Ⅰ和Ⅱ类水标准。除马来眼子菜外,其余4种沉水植物对主要污染物的净化效果存在较大差异,以四季常青苦草的综合净化效果最好,出水COD、TP、NH+4-N、NO-3-N和TN的平均浓度分别为36.83、0.269、1.17、0.563和3.31 mg·L~(-1),平均去除率分别达到41.32%、72.77%、84.29%、79.28%和76.72%。黑藻次之,接着是狐尾藻,而普通苦草的去污效果较差。综合考虑其对模拟城市污水处理厂尾水的深度处理效率,宜选择四季常青苦草作为表面流人工湿地的优选沉水植物。     

利用沉水植物生长期收割进行富营养化水体生态管理的实地研究

在以再生水为补水水源的圆明园玉玲珑水域进行沉水植物收割实验,自2011年4—12月间每隔半个月监测一次水质。结果表明,通过在生长期收割沉水植物,玉玲珑水体TP、SRP、TN、NH4+-N、NO3--N和COD的平均浓度可维持在0.1、0.04、0.86、0.1、0.32和18 mg/L左右,水质保持在Ⅲ类至Ⅳ类地表水之间;与之对照的不收割沉水植物的玉玲珑进水口水域,9月沉水植物开始死亡腐烂,TP、SRP、TN、NH4+-N最高分别可达0.5、0.1、2.4和0.60 mg/L;作为对照的另一以挺水植物为主的水域,水质普遍劣于有大量沉水植物生长的水域,TP、SRP、TN、NH4+-N最高分别可达1.2、0.60、6.1和0.61mg/L。圆明园的实地实验表明,沉水植物有很强的净化水质作用,通过生长期收割,能够进一步强化其水质净化作用,可以作为一项对富营养化水体进行生态管理的有效措施进行推广。     

黑藻根系分泌物对不同磷浓度的响应

为探明湿地沉水植物根系分泌物对面源污染物磷的响应机制,利用气相色谱/质谱联用(GC/MS)测定湿地典型沉水植物黑藻(Hydrilla verticillata)的根系分泌物,分析其在不同磷浓度及培养时间下的差异。结果表明,随着培养时间延长、磷浓度增加,黑藻总生物量均呈增加趋势。黑藻根系分泌物主要包括烷烃类、烯烃类、酯类、醇类、胺类、苯类、酮类、醛类和酸类化合物,其中烷烃类和酸类化合物种类最多。不同磷浓度及培养时间下,黑藻根系均分泌相对较多的邻苯二甲酸,表明黑藻根系调整邻苯二甲酸的分泌是适应磷环境改变的一种主要响应机制。     

人工湿地-沉水植物塘组合系统治理村镇污染水体

采用人工湿地-沉水植物塘组合系统在不同水力负荷(200、500、1 000mm/d)条件下对村镇污染水体净化效果进行研究。结果表明:在不同水力负荷和污染负荷下,组合系统整体运行稳定、耐负荷能力强、去除效果良好;出水COD达到《地表水环境质量标准》(GB 3838—2002)的Ⅲ类标准,出水总磷达到GB 3838—2002的Ⅴ类标准,出水总氮达到《城镇污水处理厂污染物排放标准》(GB 18918—2002)的一级A标准,出水氨氮达到GB 18918—2002的一级B标准。除溶解性正磷酸盐以外,组合系统对污染物的去除效果均随着水力负荷的增加整体呈现出下降趋势,低水力负荷去除效果最优。沉水植物塘在氮、磷去除效果上优于人工湿地,而人工湿地在COD去除效果上则优于沉水植物塘。     

Algae mediate submerged macrophyte response to nutrient and dissolved inorganic carbon loading: A mesocosm study on different species

Nutrient and dissolved inorganic carbon are two important factors that influence the development and species composition of submerged macrophyte communities in shallow lake ecosystems. Yet little is known about their potential interactive effects on the submerged macrophytes and competition outcome of macrophyte–phytoplankton. We performed a mesocosm experiment to investigate the growth and photosynthetic performance of three submerged macrophytes in relation to phytoplankton/epiphyton with nutrient and bicarbonate enrichment. During the experimental period (42 d), increase in nutrient loading in water column resulted in a substantial burst of phytoplankton and epiphyton growth and increased light attenuation. When combined with nutrient loading, bicarbonate enrichment also resulted in a heavily phytoplankton- and epiphyton-dominated state, although bicarbonate enrichment per se does not cause the phytoplankton and epiphyton growth. However, increase in nutrient loading in water column had significant negative impact on individual performances (growth and photosynthesis) of the three submerged macrophytes and bicarbonate enrichment increased the effect of eutrophication on two dissected-leaf macrophytes (M. spicatum and E. nuttallii). Furthermore, our results also suggest that species-specific photosynthetic performances occurred when submerged macrophytes in an environment with high abundance of phytoplankton/epiphyton. This study highlighted that increase in nutrient loading and bicarbonate in water column is likely to interactively impact both abiotic and biotic properties of a freshwater ecosystem. The interactions of these two factors could select macrophyte species that are able to resist the shading from phytoplankton/epiphyton, making these species more dominant in natural freshwater ecosystems.     

Effects of taxonomy,sediment, and water column on C:N:P stoichiometry of submerged macrophytes in Yangtze floodplain shallow lakes,China

Carbon (C), nitrogen (N) and phosphorus (P) are the three most important essential elements limiting growth of primary producers. Submerged macrophytes generally absorb nutrients from sediments by root uptake. However, the C:N:P stoichiometric signatures of plant tissue are affected by many additional factors such as taxonomy, nutrient availability, and light availability. We first revealed the relative importance of taxonomy, sediment, and water column on plant C:N:P stoichiometry using variance partitioning based on partial redundancy analyses. Results showed that taxonomy was the most important factor in determining C:N:P stoichiometry, then the water column and finally the sediment. In this study, a significant positive relationship was found between community C concentration and macrophyte community biomass, indicating that the local low C availability in macrophytes probably was the main reason why submerged macrophytes declined in Yangtze floodplain shallow lakes. Based on our study, it is suggested that submerged macrophytes in Yangtze floodplain shallow lakes are primarily limited by low light levels rather than nutrient availability.

     

Metal accumulation by submerged macrophytes in eutrophic lakes at the watershed scale

Metal concentrations (Al, Ba, Ca, K, Li, Mg, Na, Se, Sr and Ti) in submerged macrophytes and corresponding water and sediments were studied in 24 eutrophic lakes along the middle and lower reaches of the Yangtze River (China). Results showed that these eutrophic lakes have high metal concentrations in both water and sediments because of human activities. Average concentrations of Al and Na in tissues of submerged macrophytes were very high in sampled eutrophic lakes. By comparison, Ceratophyllum demersum and Najas marina accumulated more metals (e.g. Ba, Ca, K, Mg, Na, Sr and Ti). Strong positive correlations were found between metal concentrations in tissues of submerged macrophytes, probably because of co-accumulation of metals. The concentrations of Li, Mg, Na and Sr in tissues of submerged macrophytes significantly correlated with their corresponding water values, but not sediment values.     

Physico-chemical characteristics and pollution level of Lake Nainital (U.P., India): role of macrophytes and phytoplankton in biomonitoring and phytoremediation of toxic metal ions

Lake Nainital is the sole source of drinking water for the local people and even to majority of tourists. In background of lake utility and its importance at national level, such study is essential which is focused on toxic metal pollution and current nutrient status of the lake and their magnification by algae and macrophytes. Study has shown that lake water is rich in nutrients which supports growth of many aquatic macrophytes and algal blooms. Besides, water is contaminated with metals like Cr, Cu, Fe, Mn, Ni, Pb and Zn. Concentration of some of them like Fe, Pb and Ni were higher than the recommended maximum permissible limits. Concentration of these metals were also found high in lake sediments. The level of metals amongst various components of lake varied considerably in different season. Plants and algae growing therein accumulated appreciable amount of metals and water roots of Salix being more efficient than others. High metal removing potential of these plants may be significant for biomonitoring studies and could be a useful phytoremediation technology to restore water quality by harvesting submerged and floating biomass inhabiting littoral zone of the lake.     

Effects of juvenile crucian carp (Carassius carassius) removal on submerged macrophyte growth—implications for subtropical shallow lake restoration

Environmental Science and Pollution Research - Rapid expansion of juvenile fish after biomanipulation can delay the successful restoration of submerged macrophytes, leading to a turbid water status...     

不同水层光照强度对4种沉水植物生长的影响

选取金鱼藻(Ceratophyllum demersum)、轮叶黑藻(Hydrilla verticillata)、水盾草(Cabombacaroliniana)、苦草(Vallisneria gigantean)为试验材料,研究不同水层的光照强度对其存活率、株高、生物量等的影响,旨在找出这4种沉水植物在自然条件下的最...     

Effects of herbicides on two submersed aquatic macrophytes, Potamogeton pectinatus L. and Myriophyllum sibiricum Komarov, in a prairie wetland

Clopyralid, picloram, 2,4-D and a mixture of 2,4-D plus picloram, (Tordon 202C) were added to the water of 1 m square enclosures in a prairie wetland in Saskatchewan, Canada to produce concentrations of 0.01 and 0.1 mg active ingredient litre(-1). Effects on the submersed macrophytes, Potamogeton pectinatus and Myriophyllum sibiricum, were monitored by taking repeated measurements of plant weight, flower and tuber production and inspecting for injuries at 30 and 60 days after application. Clopyralid did not inhibit weight gain (growth) in either species, but stimulated growth and flowering by M. sibiricum at 0.01 mg litre(-1) and tuber production by P. pectinatus at both rates. The low rate of 2,4-D stimulated flowering by M. sibiricum and tuber production by P. pectinatus, whereas the high rate inhibited growth of M. sibiricum and injured both species. Picloram did not affect growth of either species, but injured M. sibiricum at both concentrations and inhibited flowering at 0.1 mg litre(-1). Tordon 202C at 0.1 mg litre(-1) caused reduced growth and flowering in M. sibiricum and injured both species; 0.01 mg litre(-1) also injured M. sibiricum. Mortality resulted only from Tordon 202C and 2,4-D. Field data are lacking to assess the extent to which submerged macrophytes in prairie ponds are exposed to harmful concentrations of herbicide from aerial spraying, drift from ground application, runoff or wind erosion of soil.     

Management of fresh water weeds (macrophytes) by vermicomposting using Eisenia fetida

In the present study, potential of Eisenia fetida to recycle the different types of fresh water weeds (macrophytes) used as substrate in different reactors (Azolla pinnata reactor, Trapa natans reactor, Ceratophyllum demersum reactor, free-floating macrophytes mixture reactor, and submerged macrophytes mixture reactor) during 2 months experiment is investigated. E. fetida showed significant variation in number and weight among the reactors and during the different fortnights (P <0.05) with maximum in A. pinnata reactor (number 343.3?±?10.23 %; weight 98.62?±?4.23 % ) and minimum in submerged macrophytes mixture reactor (number 105?±?5.77 %; weight 41.07?±?3.97 % ). ANOVA showed significant variation in cocoon production (F₄?=?15.67, P <0.05) and mean body weight (F₄?=?13.49, P <0.05) among different reactors whereas growth rate (F₃?=?23.62, P <0.05) and relative growth rate (F₃?=?4.91, P <0.05) exhibited significant variation during different fortnights. Reactors showed significant variation (P <0.05) in pH, Electrical conductivity (EC), Organic carbon (OC), Organic nitrogen (ON), and C/N ratio during different fortnights with increase in pH, EC, N, and K whereas decrease in OC and C/N ratio. Hierarchical cluster analysis grouped five substrates (weeds) into three clusters—poor vermicompost substrates, moderate vermicompost substrate, and excellent vermicompost substrate. Two principal components (PCs) have been identified by factor analysis with a cumulative variance of 90.43 %. PC1 accounts for 47.17 % of the total variance represents “reproduction factor” and PC2 explaining 43.26 % variance representing “growth factor.” Thus, the nature of macrophyte affects the growth and reproduction pattern of E. fetida among the different reactors, further the addition of A. pinnata in other macrophytes reactors can improve their recycling by E. fetida.     

Macrophyte development and habitat characteristics in Sweden's large lakes

The four largest Swedish lakes, V?nern, V?ttern, Hj?lmaren, and M?laren, were surveyed by means of aerial IR-color photography in the 1970s. Along small slope gradients in all lakes the emergent communities extended to a width of hundreds of meters, while the extent on steeper slopes was a few meters. Because of the fractionate shape, L. M?laren has a very long shoreline, which promotes vegetation growth in the transition zone between land and water. Sheltered conditions are numerous and water lilies and other floating leaved and freely floating plants are abundant. Emergent as well as submerged macrophytes grow vigorously in the northernmost part of the oligotrophic lake V?ttern. In L. V?nern exposed shores pre-dominate, but sheltered bays and archipelagos are overgrown with reeds. In the shallow lake Hj?lmaren monospecific stands of Phragmites australis are dominant. Recurrent surveys of L. M?laren and L. V?nern in the 1990s showed changes that could be connected to the watertable fluctuations, which have been stabilized since the first investigation. Reeds and water lilies expanded in sheltered parts of the lakes, while the distribution of reed stands growing at their deep limit decreased.     

大型水生植物对骆马湖氮、磷元素的影响

对骆马湖有草区和无草区水体和沉积物中氮、磷元素含量分析,结果表明:无草区水体中总氮、总磷含量高于有草区;有草区表层沉积物总氮含量随时间变化明显,而无草区表层沉积物总氮含量随时间的变化很小;有草区与无草区表层沉积物中总磷含量的时间变化并无明显差异;有草区表层沉积物总氮含量基本上均高于无草区,而有草区表层沉积物总磷含量均要低于无草区。骆马湖有草区与无草区采样点沉积物碱性磷酸酶活性大小在58.41～315.07 mg/(kg.h)范围内变化,有草区的碱性磷酸酶的活性普遍低于无草区的碱性磷酸酶活性。在湖泊中种植大型水生植物确实可以减少水体污染,达到净化水质的目的。