Ecogeographical tolerance range variation in aquatic macrophytes

A portion of central Canada (area B) and a smaller, soft-water area within it on the Precambrian Shield (area A) were surveyed for aquatic macrophytes in relation to eight water chemistry parameters. pH, total dissolved solids and total alkalinity appeared to be the three most important factors correlated with macrophyte distribution. T-tests indicated that species for which water chemistry affinities were not discrepant in areas A and B could be identified as specialized or unspecialized plants with respect to area A. Other species behaved quite differently in the two areas. In most cases for pH and dissolved inorganics macrophytes showed lower mean values and lower upper tolerance range limits in area A than in area B, reflecting the prevailing water chemistry values in the two areas. These results suggested that adaptation had occurred in one or both sets of populations. A number of interspecific associations were demonstrated in area A, many of which coincided with similarities in water chemistry affinities.     

Synthesis and release of cyclic adenosine 3':5'-monophospliate by aquatic macrophytes

Tissues from the aquatic macrophyte species Scirpus subterminalis, Najas flexilis, Ceratophyllum demcrsum, Potamogeton zosteriformis, and Nuphar advena contain cAMP in quantities similar to those reported in algae. Scirpus, Najas , and Ceratophyllum released cAMP into the extracellular media in quantities which varied interspecifically and intraspecifically in differing media. Macrophytic release of cAMP may be an important source of dissolved cAMP in lakewater.     

The effects of lime addition on aquatic macrophytes in hard water: in situ and microcosm experiments

1. Aquatic macrophytes are abundant in ponds and canals that are constructed in semi‐arid regions for water storage and conveyance, as well as in lakes that are culturally enriched. 2. Addition of Ca(OH)₂ to two hardwater ponds at 250 or 275 mg L^–1 caused an immediate eradication of submersed aquatic plants. Although these ponds are well‐buffered (alkalinity: 2.57–3.94 mequiv L^–1; pH: 8.1–9.0), lime addition caused an immediate increase in pH of 0.2–3 units. 3. Application of 135 mg L^–1 Ca(OH)₂ for 24 h or 210 mg L^–1 Ca(OH)₂ for 65 h to two irrigation canals had no effect on macrophyte biomass at the lower concentration and duration, but resulted in the elimination of aquatic macrophytes 1 month after the higher concentration, longer duration treatment. 4. Unlike the macrophyte control achieved following application of 210–275 mg L^–1 Ca(OH)₂ to ponds or canals, microcosm experiments in which lime formulation [slaked lime (Ca(OH)₂), calcite (CaCO₃), or a 1 : 1 mixture] and concentrations (up to 1500 mg L^–1) were manipulated failed to elicit a consistent change in macrophyte biomass. Macrophytes in microcosms treated for the short‐term (23–33 days) with ≥ 200 mg L^–1 Ca(OH)₂ or a mixed Ca(OH)₂/CaCO₃ formulation always lost pigmentation, but biomass was not consistently reduced. 5. Declines in macrophyte biomass following treatment of ponds and canals may have been triggered by a short‐term rise in pH which, in these relatively warm (22–23 °C) alkaline (2.28–3.94 mequiv L^–1) systems, would have resulted in low concentrations of free CO₂ and bicarbonate for photosynthesis.     

淡水水生植物化感作用研究进展

水生植物的化感作用对淡水生态系统中水草的可持续管理和湖泊富营养化的生态控制具有非常重要的意义。本文综述了淡水水生植物化感作用的发展历史和研究现状,讨论了水生植物化感作用研究过程中所涉及的实验方法、生物测试方法、化感物质分离方法以及影响水生植物化感研究的环境因素。抑藻圈试验、藻类生长试验和浮萍生长试验是常用的生物测试方法;采用共生培养或单独培养的方法,从种植水中分离、鉴定化感物质,对证实复杂水环境中水生植物化感作用的存在,研究它们化感物质的释放途径和作用机理都具有十分重要的作用。     

Species richness of aquatic macrophyte communites in Central Canada

Aquatic macrophyte species richness (SR) was examined at 430 sites in the central Canadian region in relation to water body type, bottom substrate and 8 water chemistry parameters. SR was highest in rivers and lakes, intermediate in creeks, and lowest in ponds. The highest values occurred where granitic bedrock, highly organic substrates or sand predominated. SR was significantly inversely correlated in the study area as a whole with 7 of the water chemistry parameters; of these, total alkalinity was the most important. However, the relative importance of the respective parameters differed for various water body types. The relationship between SR and phosphorus was positive in ponds, but negative for all other water body types. Stepwise sultiple regression analysis identified phosphorus, total alkalinity and dissolved organic matter as important factors in ponds; sulphate, total alkalinity and chloride in lakes, and sulphate and phosphorus in lotic habitats. Log transformations improved the correlations for some variables. However, the water chemistry parameters examined accounted for less than half of the total variability in SR. Apparently SR depends on many different factors, including surface areaand bottom type, whose relative contributions vary with situation.     

Trait‐based community assembly of aquatic macrophytes along a water depth gradient in a freshwater lake

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水生植物引种的生态安全评价

随着水生植物的大量应用,水域环境的生态安全越来越受到关注。水生植物入侵具有一定的生物学、区系地理、生态位和生境特征,对水生植物的生态安全评价可在一定程度上防止水生植物引种的盲目性。该文针对来自水生外来入侵植物的生态安全威胁,分析了水生外来入侵植物的入侵特征及其危害,提出了水生植物引种的生态安全评价的内容、程序、指标体系和方法。     

The biogeography of aquatic macrophytes in North America since the Last Glacial Maximum

Aim To document the post‐glacial migration of the major aquatic macrophytes of North America. Location North America north of Mexico. Methods Aquatic macrophyte pollen were extracted from the North American Pollen Database. The modern pollen distribution was mapped and related to the climate to document the geographical and climatic constraints on these taxa. The fossil pollen were mapped at 2‐ka intervals for the past 21 ka. Results Numerous genera were present in ice‐free Alaska during the Last Glacial Maximum, and south of the Laurentide Ice Sheet in the southeast. Those taxa with the widest modern climatic ranges migrated rapidly into ice‐marginal areas, first in the west and then in the east of North America. Subsequent changes in the range and abundance were smaller. Main conclusions There were four migration routes of aquatic macrophytes during the late‐glacial and post‐glacial periods: a southward migration from Alaska between 14–13 and ka, a northern migration in the west at the same time into the ice‐free Cordilleran region, and movements east and west of Appalachia as early as 19 ka for some taxa into the lower Mississippi and into the upper Mississippi and Great Lakes by 11 ka. As the Laurentide ice sheet wasted, aquatic taxa with the broadest contemporary temperature tolerances rapidly occupied ice‐marginal environments.     

Managing water quality with aquatic macrophytes

The principal sources of water for human use are lakes, rivers, soil moisture and relatively shallow groundwater basins. Water quality in lakes and reservoirs is subjected to the natural degradation, processes of eutrophication and the impacts of human activities. Water quality problems can often be as severe as those of water availability but less attention has been paid to them, particularly in developing countries. Currently additional sustainable ways to mitigate the degradation of water quality are being researched all over the world. Phytoremediation is one of the serious efforts towards the sustainability. Most of the aquatic macrophytes are naturally occurring and well adapted for their surroundings. Aquatic macrophytes have the capability to remove excessive nutrient load from the water that otherwise cause eutrophication of the water body. Aquatic macrophytes absorb nutrient mineral ions from water column and influence metal retention indirectly by acting as traps for particulate matter, by slowing the water current and favoring sedimentation of suspended particles. Aquatic macrophytes also reduce sediment resuspension by offering wind protection. The use of aquatic macrophyte for treatment of wastewater to mitigate variety of pollution level is one of the most researched issues all over the world. Aquatic plant species are very specific for the uptake of nutrients. Owing to this specificity, the selection of the aquatic plant species is one of the skilled tasks prior to the design of a water treatment facility. An effort has been made in this review to cover the most researched aquatic flora for mitigation purposes and their possible use in a mesocosm as the selection of an appropriate aquatic plant specie reduce the time and cost of the treatment processes.     

The ecology of Potamogeton species in central North America

The distribution of 17 Potamogeton species was examined at 430 sites in central North America with respect to water body type, bottom substrate and 8 water chemistry parameters (pH, total dissolved solids, total alkalinity, chloride, sulphate, phosphorus, combined nitrate and nitrite, and dissolved organic matter). All except 2 of the species showed statistically significant distributions with respect to some of the environmental parameters examined. Each species occupied a different combination of chemical parameter ranges. The species formed a distribution spectrum with respect to water chemistry, with P. epihydrus and P. obtusifolius frequenting low inorganic concentrations at one end of the scale, and P. filiformis, P. pectinatus and P. vaginatus at the other end, these species characterized by high mean inorganic values and occurring most often in saline or alkaline habitats. While 41 significant positive interspecific associations were found within the genus in lentic waters, only 4 were apparent in lotic habitats. Potamogeton species richness (PR) was related to water body and bottom type, with lakes and sand bottoms showing the highest mean PR values. Stepwise multiple regression analysis showed that, in the area as a whole, the water chemistry parameters examined accounted for <25% of the observed variability in PR. The relative importance of individual chemical parameters in relation to PR varied in different water body types.     

Effects of water velocity on photosynthesis and dark respiration in submerged stream macrophytes

The effects of flow velocities on dark respiration and net photosynthesis of eight submerged stream macrophytes were examined in a laboratory oxygen chamber. The shoots/leaves were exposed to saturating free-CO₂ concentrations and were attached basally so that they could move in the flowing water. Net photosynthesis declined by 34–61% as flow velocity increased from 1 to 8.6cm s^?1, while dark respiration increased 2.4-fold over the same range. The increase in dark respiration could only account for between 19 and 67% of the decrease in net photosynthesis. The relationship between flow velocity (U) and net photosynthesis (P) was described by: P=b×U^a. The exponent, a, varied from -0.20 to –0.48 and showed a negative correlation to the surface: volume (SA: V) ratio of the plants, i.e. species with high SA: V ratio were more sensitive to flow. In contrast, net photosynthesis of plants firmly attached to a supporting frame was not significantly affected by increasing flow velocity. This result indicates that the physical stress imposed on the plants by agitation or stretching in the flowing water is a key factor for the observed response.     

Seasonality/aseasonality of aquatic macrophytes in Southern Hemisphere inland waters

The term aseasonality is used in this paper to describe environmental conditions which either lack annual seasonal change or have periodicities of change which are longer or shorter than the seasons. Environmental factors act on plants either as stresses or disturbances and changes in environment can signal the onset of conditions which are favourable or unfavourable to plant growth and reproduction. Plant life-histories are thus adapted to these environmental factors and respond to them with both seasonal and aseasonal periodicities, depending on their manner of occurrence and effect on the plants. A review of pertinent studies from the Southern Hemisphere shows that plants of the same life-form (submerged, floating, emergent) might differ in the types of adaptation and response to environmental conditions according to latitude but that the periodicity of response could be seasonal or aseasonal regardless of latitude. The concept of seasonality versus aseasonality is therefore misleading and an oversimplification of the variety of periodicities with which the environment acts on plant genotypes. Limnological principles of the Northern Hemisphere are applicable to aquatic macrophytes in the Southern Hemisphere but there is a particular need for research into the effects of biotic variables and water level fluctuations on aquatic plants and communities in the latter.     

东太湖水生植物群落结构的演变及其沼泽化

2002年东太湖水生植被调查结果表明,沉水植被和浮叶植被是该湖水生植被的主要生态类型,分布面积分别占全湖总面积73.6%和18.3%。东太湖水生植被主要有9个群丛,其中沉水植被主要的5个群丛是伊乐藻(外来种)群丛、金鱼藻群丛、伊乐藻 微齿眼子菜群丛、菜-伊乐藻 微齿眼子菜群丛、苦草 竹叶眼子菜 黑藻群丛,其分布面积分别占东太湖植被总面积的30.7%、17.2%、16.7%、15.8%、9.3%。随着对东太湖的不断改造和资源的不断利用,20世纪60年代东太湖人工种植沼泽植被菰群丛,20世纪80年代初环湖水陆交错带被围垦而芦苇群丛消失,微齿眼子菜替代竹叶眼子菜而占据东太湖40%的水面。近10a来,东太湖网围养蟹迅速发展,占全湖总植被面积25.6%的沼泽植物——菰群丛及其占40%的微齿眼子菜群丛被清除,外来种伊乐藻和无根植物金鱼藻分布面积达90%的湖区。东太湖水生植被由20世纪50年代的原生演替到现在的次生演替,群落演变激烈,同时东太湖沼泽化进程加剧。     

Decomposition dynamics of aquatic macrophytes in the lower Atchafalaya, a large floodplain river

Decomposition of aquatic macrophytes can considerably influence carbon cycling and energy flow in shallow freshwater aquatic ecosystems. The Atchafalaya River Basin (ARB) is a large floodplain river in southern Louisiana that experiences a seasonal floodpulse and is spatially composed of a mosaic of turbid riverine and stagnant backwater areas. During two seasons, winter and fall of 1995, we examined decomposition of four common aquatic macrophytes in the ARB: water hyacinth (Eichhornia crassipes), arrowhead (Sagittaria platyphylla), coontail (Ceratophyllum demersum) and hydrilla (Hydrilla verticillata). To determine decay rates, we used litter bags of two mesh sizes (5 mm and 0.25 mm) and analyzed data with a single exponential decay model. Analysis of decay rates established several trends for aquatic macrophyte decomposition in the ARB. First, macrophytes decayed faster in fall than winter due to the effect of increased temperature. Second, macroinvertebrates were the primary decomposers of macrophytes in riverine sites and microbes were the primary decomposers in backwater areas. These trends may have been related to decomposer-habitat interactions, with well-oxygenated riverine sites more hospitable to invertebrates and backwater areas more favorable to microbes because of high organic inputs and reduced flow. Decay rates for macrophytes, ranked from slowest to fastest, were E. crassipes<S. platyphylla<C. demersum<H. verticillata. Slower decomposition of E. crassipes was probably a result of microbial inhibition by the waxy-cutin outer layer and low nutritional value. The accelerated decomposition of C. demersum and H. verticillata was most likely a function of the large surface area of the highly dissected leaves. Macroinvertebrate numbers were twice as high in riverine sites compared to backwater sites. In the winter, amphipods Gammarus spp. and Hyallela azteca composed a large percentage of the total density on detritus. In the fall, Caenis sp. was prevalent in the backwater habitat and dipterans were abundant in the riverine site. We investigated the microbial component involved in the decomposition of E. crassipes and S. platyphylla and found that the highest microbial respiration rates occurred early in the winter at the backwater site. Bacterial density in the winter on E. crassipes and S. platyphylla averaged 1.4×10⁶ cm^-2 after two days and decreased to 2.0×10⁵ cm^-2 after 28 d. Our results emphasized the importance of the microbial community in the decomposition of macrophytes in the ARB, especially in backwater habitats and in the early stages of decay.     

Bird abundance and species richness on Florida lakes: influence of trophic status,lake morphology,and aquatic macrophytes

Data from 46 Florida lakes were used to examine relationships between bird abundance (numbers and biomass) and species richness, and lake trophic status, lake morphology and aquatic macrophyte abundance. Average annual bird numbers ranged from 7 to 800 birds km^–2 and bird biomass ranged from 1 to 465 kg km^–2. Total species richness ranged from 1 to 30 species per lake. Annual average bird numbers and biomass were positively correlated to lake trophic status as assessed by total phosphorus (r = 0.61), total nitrogen (r = 0.60) and chlorophyll a (r = 0.56) concentrations. Species richness was positively correlated to lake area (r = 0.86) and trophic status (r = 0.64 for total phosphorus concentrations). The percentage of the total annual phosphorus load contributed to 14 Florida lakes by bird populations was low averaging 2.4%. Bird populations using Florida lakes, therefore, do not significantly impact the trophic status of the lakes under natural situations, but lake trophic status is a major factor influencing bird abundance and species richness on lakes. Bird abundance and species richness were not significantly correlated to other lake morphology or aquatic macrophyte parameters after the effects of lake area and trophic status were accounted for using stepwise multiple regression. The lack of significant relations between annual average bird abundance and species richness and macrophyte abundance seems to be related to changes in bird species composition. Bird abundance and species richness remain relatively stable as macrophyte abundance increases, but birds that use open-water habitats (e.g., double-crested cormorant, Phalacrocorax auritus) are replaced by species that use macrophyte communities (e.g., ring-necked duck, Aythya collaris).     

Application of phytoremediation technology in decontamination of a fish culture pond fed with coal mine effluent using three aquatic macrophytes

Abstract

In the present study, three aquatic macrophytes, Eichhornia crassipes, Salvinia molesta, and Pistia stratiotes were used to assess their relative efficacies in decontamination of a fish culture pond, regularly fed with coal mine effluent (CME). The level of metals like Fe, Mn, Ni, Zn, Cu, Pb, Cr, and Cd were much higher in CME-fed pond water than their recommended limits in drinking water set by the Bureau of Indian standards and in effluents by the Environmental Protection Agency. The levels of metal were lowered substantially in CME-fed pond water after exposure of the above plants to such water, however, metal levels in the plants increased tremendously. The increased metal levels in plants severely damaged their physiological and biochemical processes. The contents of chlorophyll a, b and carotenoid were reduced by 63.2, 64.2, and 46.3%, respectively, in E. crassipes, 41, 57.4, and 57.8% in S. molesta, and 42, 62, and 61% in P. stratiotes. The accumulating metals also generated oxidative stress in plants, as evident from the increased superoxide dismutase and catalase activities and enhanced malondialdehyde content. The E. crassipes was the most potent in absorbing the metals from the CME-fed pond water, followed by S. molesta and P. stratiotes.     

Effects of mine effluent on uptake of Co,Ni, Cu,As, Zn,Cd, Cr and Pb by aquatic macrophytes

Concentrations of Ni, Co, Cu, Pb, Zn, Cd, Cr and As were determined in aquatic sediments, water and macrophytes collected from a fluvial system, contaminated by mine effluents. Myriophyllum verticillatum collected in May below the trace element point source accumulated 169 µg/g of Ni, 860 µg/g of Co, 37 µg/g of Cu, 31 µg/g of Pb, 92 µg/g of Zn, 6.9 µg/g of Cr and 1,200 µg/g of As (concentrations in dry weight). The aquatic macrophytes Nymphaea odoratae and Pontederia cordata accumulated the investigated trace elements to a much lesser extent. The concentrations of trace elements in Myriophyllum verticillatum decreased from May to August. Correlations were found between the concentrations of total Ni, Co and Cu in the bottom sediment and in the submerged macrophytes. However, there was no correlation between the amounts of these trace elements extractable by 0.5 N HCl from the sediments and the concentrations in the macrophytes.     

用镶嵌组合植物群落控制湖泊饮用水源区藻类及氮污染

依据湖泊中不同生态类型水生高等植物的微生境特点,设计建造了由漂浮、浮叶、沉水植物为优势种的斑块小群丛构成的镶嵌组合水生植物群落（ＭｏｓａｉｃＣｏｍｍｕｎｉｔｙｏｆＭａｃｒｏｐｈｙｔｅｓ：ＭＣＭ）,并在太湖五里湖一湖湾内以动态模拟试验,从群落水平研究了水生高等植物群落对富营养化湖泊饮用水源区湖水的净化能力。结果表明,富营养化湖水经ＭＣＭ净化后,藻类生物量（以Ｃｈｌａ计）下降５７７％,藻类数量下降２～３个数量级,氨氮下降６６７％,总氮下降６００％,水质得到明显改善。与以该湖湾湖水为水源的水厂出水相比,经ＭＣＭ净化的湖水其氨氮比水厂出水的氨氮平均低４５１％,总氮低３７３％,可见经ＭＣＭ净化的湖水部分指标优于同源的自来水。综合群落的微生境特征及水生高等植物群落内硝化反硝化细菌分布特点,探讨了ＭＣＭ的除氮机理。     

Diversity of aquatic macrophytes in relation to environmental factors in the Slatina river (Slovakia)

Distribution and plant mass of aquatic macrophytes, and their relation to environmental conditions was studied in the submontane-colline Slatina river in 2004. Diversity of macrophytes was low, only 8 vascular plants, 3 mosses and group Algae filamentosae were found. Myriophyllum spicatum is dominant species, Fontinalis antipyretica, Rhynchostegium riparioides and Algae filamentosae are frequent. Interactions between flow class, bed material, depth of water and the first three mentioned macrophytes, as well as Jungermannia leiantha were detected. Sparganium erectum prefers more antrophogenic conditions and Myriophyllum spicatum prefers the light. According to cluster analysis, three distinct and ecologically well separated parts of the river were identified. Based on Reference index, poor ecological status for the studied part of the Slatina river was estimated.