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48-402: Traditional or primitive rafts were constructed of wood, bamboo or reeds ; early buoyed or float rafts use inflated animal skins or sealed clay pots which are lashed together. Modern float rafts may also use pontoons , drums , or extruded polystyrene blocks. Depending on its use and size, it may have a superstructure , masts, or rudders. Timber rafting is used by the logging industry for

96-408: A micro-organism or may be transferred from one plant to another variety better adapted to the environmental conditions at the cleanup site. For example, genes encoding a nitroreductase from a bacterium were inserted into tobacco and showed faster removal of TNT and enhanced resistance to the toxic effects of TNT. Researchers have also discovered a mechanism in plants that allows them to grow even when

144-405: A considerable amount of contaminants from the soil. Phytoextraction has been growing rapidly in popularity worldwide for the last twenty years or so. Typically, phytoextraction is used for heavy metals or other inorganics. At the time of disposal, contaminants are typically concentrated in the much smaller volume of the plant matter than in the initially contaminated soil or sediment. After harvest,

192-409: A high speed. This is not to be confused with other double reeds like that of the oboe which uses two reeds made from the giant reed leaning against each other. The leaves, roots, seeds and stems of phragmites are edible. Young shoots can be cooked or eaten raw just like bamboo shoots. The young stems, "while still green and fleshy, can be dried and pounded into a fine powder, which when moistened

240-533: A large amount of decaying dead plant material can depress oxygen levels in the water and kill all the fish in a pond or small lake. Some success has also been obtained using goats to graze on Phragmites , controlled burns, and native wild rice crops. Biological controls have been suggested to be the most likely control method to succeed and biocontrols have been approved for introduction in North America Unfortunately, biocontrols may destroy

288-448: A lower level of the contaminant will remain in the soil, so the growth/harvest cycle must usually be repeated through several crops to achieve a significant cleanup. After the process, the soil is remediated. Of course many pollutants kill plants, so phytoremediation is not a panacea. For example, chromium is toxic to most higher plants at concentrations above 100 μM·kg−1 dry weight. Mining of these extracted metals through phytomining

336-521: A more cost effective solution. Phytoremediation may be applied to polluted soil or static water environment. This technology has been increasingly investigated and employed at sites with soils contaminated heavy metals like with cadmium , lead , aluminum , arsenic and antimony . These metals can cause oxidative stress in plants, destroy cell membrane integrity, interfere with nutrient uptake, inhibit photosynthesis and decrease plant chlorophyll . Phytoremediation has been used successfully in

384-425: A transformation pathway has been proposed. Phytostimulation (or rhizodegradation) is the enhancement of soil microbial activity for the degradation of organic contaminants, typically by organisms that associate with roots . This process occurs within the rhizosphere , which is the layer of soil that surrounds the roots. Plants release carbohydrates and acids that stimulate microorganism activity which results in

432-445: Is a conceivable way of recovering the material. Hyperaccumulating plants are often metallophyte . Induced or assisted phytoextraction is a process where a conditioning fluid containing a chelator or another agent is added to soil to increase metal solubility or mobilization so that the plants can absorb them more easily. While such additives can increase metal uptake by plants, they can also lead to large amounts of available metals in

480-869: Is almost exclusively an inflatable raft , manufactured of flexible materials for use on whitewater . In biology , particularly in island biogeography , non-manmade rafts are an important concept. Such rafts consist of matted clumps of vegetation that has been swept off the dry land by a storm , tsunami , tide , earthquake or similar event; in modern times they sometimes also incorporate other kind of flotsam and jetsam , e.g. plastic containers. They stay afloat by its natural buoyancy and can travel for hundreds, even thousands of miles and are ultimately destroyed by wave action and decomposition , or make landfall. Rafting events are important means of oceanic dispersal for non-flying animals. For amphibians , reptiles , and small mammals , in particular, but for many invertebrates as well, such rafts of vegetation were often

528-452: Is also used for the mining of metals such as copper(II) compounds. The roots take up substances from the soil or water and concentrate them above ground in the plant biomass Organisms that can uptake high amounts of contaminants are called hyperaccumulators . Phytoextraction can also be performed by plants (e.g. Populus and Salix ) that take up lower levels of pollutants, but due to their high growth rate and biomass production, may remove

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576-683: Is an abundant invasive species. In the United States, prior to 1910, only a few areas in the Northeast contained non-native haplotypes of Phragmites australis. However, by 1960 non-native haplotypes were found in samples taken from coast to coast. Today, in some places like Michigan, Phragmites australis ( haplotype M) has become the dominant haplotype. The problem is invasive non-native Phragmites australis quickly spread through marshes and wetland areas. They replace native plants, deny fish and wildlife nutrients and space; block access to

624-400: Is considered an invasive species. Others have argued that the ecosystem services lost as a result of invasion outweigh the benefits gained and managers need to be responsive to invasion control. P. australis is cultivated as an ornamental plant in aquatic and marginal settings such as pond- and lakesides. Its aggressive colonisation means it must be sited with care. Phragmites australis

672-490: Is defined as "the use of green plants and the associated microorganisms, along with proper soil amendments and agronomic techniques to either contain, remove or render toxic environmental contaminants harmless". The term is an amalgam of the Greek phyto (plant) and Latin remedium (restoring balance). Although attractive for its cost, phytoremediation has not been demonstrated to redress any significant environmental challenge to

720-502: Is known as Phase I metabolism, similar to the way that the human liver increases the polarity of drugs and foreign compounds ( drug metabolism ). Whereas in the human liver enzymes such as cytochrome P450s are responsible for the initial reactions, in plants enzymes such as peroxidases, phenoloxidases, esterases and nitroreductases carry out the same role. In the second stage of phytotransformation, known as Phase II metabolism, plant biomolecules such as glucose and amino acids are added to

768-478: Is nearly impossible. The seeds or rhizomes can quickly lead to a new dense stand. Chemical treatment is by far the most utilized method in North America [1] . The two most common active ingredients in herbicides for Phragmites control are glyphosate and imazapyr. It is important to select the proper herbicide for the location. Further, even the proper herbicide can lead to unintended consequences since

816-430: Is one of the main wetland plant species used for phytoremediation water treatment. Waste water from lavatories and greywater from kitchens is routed to an underground septic tank-like compartment where the solid waste is allowed to settle out. The water then trickles through a constructed wetland or artificial reed bed, where bioremediation bacterial action on the surface of roots and leaf litter removes some of

864-457: Is quite different. Toxic heavy metals cannot be degraded, but organic pollutants can be, and are generally the major targets for phytoremediation. Several field trials confirmed the feasibility of using plants for environmental cleanup . Soil remediation is an expensive and complicated process. Traditional methods involve removal of the contaminated soil followed by treatment and return of the treated soil. Phytoremediation could in principle be

912-601: Is roasted like marshmallows." The seeds and rhizomes "can be ground into flour or made into gruel." In Japan, young leaves are dried, ground, and then mixed with cereal flour to make dumplings. Grazing on phragmites by large-bodied domestic herbivores, such as cows, horses, sheep, and goats, can effectively control the plant and provide a reciprocal positive benefit for humans by generating meat, milk, leather, and wool etc. Some other uses for Phragmites australis and other reeds in various cultures include baskets , mats, reed pen tips ( qalam ), and paper. Beekeepers can utilize

960-487: Is the removal of substances from soil or water with release into the air, sometimes as a result of phytotransformation to more volatile and/or less polluting substances. In this process, contaminants are taken up by the plant and through transpiration, evaporate into the atmosphere. This is the most studied form of phytovolatilization, where volatilization occurs at the stem and leaves of the plant, however indirect phytovolatilization occurs when contaminants are volatilized from

1008-426: Is used to create a small instrument similar to the clarinet called a sipsi , with either a single, as in the picture, or double pipes as in bagpipes. The reed of the zurna is made from the common reed which is flattened after removing its brittle outer glaze and the loose inner membrane, and after softening it by wetting. The result is a double reed with an elliptical opening that vibrates by closing and opening at

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1056-515: The nutrients in biotransformation . The water is then suitable for irrigation , groundwater recharge , or release to natural watercourses. Reed is used in many areas for thatching roofs. In the British Isles , common reed used for this purpose is known as Norfolk reed or water reed. However, "wheat reed" and "Devon reed", also used for thatching, are not in fact reed, but long-stemmed wheat straw. In Middle East countries Phragmites

1104-451: The root mats of meadow grasses are effective at demobilising radiosource materials especially with certain combinations of other agricultural practices. Vidal also find that the particular grass mix makes a significant difference. Phytodegradation (also called phytotransformation) uses plants or microorganisms to degrade organic pollutants in the soil or within the body of the plant. The organic compounds are broken down by enzymes that

1152-450: The biodegradation of the organic contaminants. This means that the microorganisms are able to digest and break down the toxic substances into harmless form. Phytostimulation has been shown to be effective in degrading petroleum hydrocarbons, PCBs, and PAHs. Phytostimulation can also involve aquatic plants supporting active populations of microbial degraders, as in the stimulation of atrazine degradation by hornwort . Phytovolatilization

1200-497: The case of organic pollutants, such as pesticides , explosives , solvents , industrial chemicals, and other xenobiotic substances, certain plants, such as Cannas , render these substances non-toxic by their metabolism . In other cases, microorganisms living in association with plant roots may metabolize these substances in soil or water. These complex and recalcitrant compounds cannot be broken down to basic molecules (water, carbon-dioxide, etc.) by plant molecules, and, hence,

1248-420: The chemicals they produce when decaying reduce the germination of competing seeds. Among other effects, the monocultures that result from invasion decrease spatial and temporal habitat heterogeneity and increase avian homogeneity. Recognizing the non-native form of Phragmites early in its invasion increases the opportunity for successful eradication dramatically. Once it has become established, removal by hand

1296-481: The extent that contaminated space has been reclaimed. Phytoremediation is proposed as a cost-effective plant-based approach of environmental remediation that takes advantage of the ability of plants to concentrate elements and compounds from the environment and to detoxify various compounds without causing additional pollution. The concentrating effect results from the ability of certain plants called hyperaccumulators to bioaccumulate chemicals. The remediation effect

1344-710: The following four species: Phragmites stands can provide food and shelter resources for a number of birds, insects, and other animals. Habitat benefits are often optimal when stands are thinner, and management of stands may promote more suitable habitat benefits. Some evidence suggests that a short term management rotation of 1–2 years could maximize bird and invertebrate numbers. P. australis provides ecosystem services such as nutrient sequestration, soil stabilization, and waste treatment. It has been suggested that due to its resilience to climate change impacts, P. australis may provide beneficial ecosystem services that need to be considered in coastal ecosystems, even where it

1392-446: The heavy metal pollutant into a less toxic form. Stabilization results in reduced erosion, runoff, leaching, in addition to reducing the bioavailability of the contaminant. An example application of phytostabilization is using a vegetative cap to stabilize and contain mine tailings . Some soil amendments decrease radiosource mobility – while at some concentrations the same amendments will increase mobility. Vidal et al. 2000 find

1440-582: The native subspecies population as well. When cutting under water, cutting and then flooding, or burning and then flooding, it is important that the entire Phragmites stand is completely submerged so that the plants cannot obtain oxygen. Biocontrol using two species of moth larvae (Lenisa geminipuncta and Archanara neurica) is being investigated in Ontario . Phytoremediation Phytoremediation technologies use living plants to clean up soil, air and water contaminated with hazardous contaminants. It

1488-557: The only means by which they could reach and – if they were lucky – colonize oceanic islands before human -built vehicles provided another mode of transport . Phragmites Phragmites ( / f r æ ɡ ˈ m aɪ t iː z / ) is a genus of four species of large perennial reed grasses found in wetlands throughout temperate and tropical regions of the world. The World Checklist of Selected Plant Families, maintained by Kew Garden in London , accepts

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1536-402: The physiology of the plant. Even cultivars within the same species have varying abilities to accumulate pollutants. A range of processes mediated by plants or algae are tested in treating environmental problems.: Phytoextraction (or phytoaccumulation or phytosequestration ) exploits the ability of plants or algae to remove contaminants from soil or water into harvestable plant biomass. It

1584-476: The plant roots secrete and these molecules are then taken up by the plant and released through transpiration. This process works best with organic contaminants like herbicides, trichloroethylene , and methyl tert -butyl ether . Phytotransformation results in the chemical modification of environmental substances as a direct result of plant metabolism , often resulting in their inactivation, degradation (phytodegradation), or immobilization (phytostabilization). In

1632-500: The plant. This ensures that the xenobiotic is safely stored, and does not affect the functioning of the plant. However, preliminary studies have shown that these plants can be toxic to small animals (such as snails), and, hence, plants involved in phytotransformation may need to be maintained in a closed enclosure. Hence, the plants reduce toxicity (with exceptions) and sequester the xenobiotics in phytotransformation. Trinitrotoluene phytotransformation has been extensively researched and

1680-449: The polarized xenobiotic to further increase the polarity (known as conjugation). This is again similar to the processes occurring in the human liver where glucuronidation (addition of glucose molecules by the UGT class of enzymes, e.g. UGT1A1 ) and glutathione addition reactions occur on reactive centres of the xenobiotic. Phase I and II reactions serve to increase the polarity and reduce

1728-1083: The pollutant involved (for example: more than 1000 mg/kg of dry weight for nickel , copper , cobalt , chromium or lead ; or more than 10,000 mg/kg for zinc or manganese ). This capacity for accumulation is due to hypertolerance , or phytotolerance : the result of adaptative evolution from the plants to hostile environments through many generations. A number of interactions may be affected by metal hyperaccumulation, including protection, interferences with neighbour plants of different species, mutualism (including mycorrhizae , pollen and seed dispersal), commensalism, and biofilm . As plants are able to translocate and accumulate particular types of contaminants, plants can be used as biosensors of subsurface contamination, thereby allowing investigators to quickly delineate contaminant plumes. Chlorinated solvents, such as trichloroethylene , have been observed in tree trunks at concentrations related to groundwater concentrations. To ease field implementation of phytoscreening, standard methods have been developed to extract

1776-428: The pollutant. The plant immobilizes the pollutants by binding them to soil particles making them less available for plant or human uptake. Unlike phytoextraction, phytostabilization focuses mainly on sequestering pollutants in soil near the roots but not in plant tissues. Pollutants become less bioavailable, resulting in reduced exposure. The plants can also excrete a substance that produces a chemical reaction, converting

1824-406: The pollution concentration in the soil is lethal for non-treated plants. Some natural, biodegradable compounds, such as exogenous polyamines , allow the plants to tolerate concentrations of pollutants 500 times higher than untreated plants, and to absorb more pollutants. A plant is said to be a hyperaccumulator if it can concentrate the pollutants in a minimum percentage which varies according to

1872-593: The reeds to make nesting. In the Philippines , Phragmites is known by the local name tambo . Reed stands flower in December, and the blooms are harvested and bundled into whisk brooms called "walis". Hence the common name of household brooms is walis tambo . Reeds have been used to make arrows and weapons such as spears for hunting game. Some Phragmites , when introduced by accident or intent, spread rapidly. In tropics and subtropics, Phragmites karka

1920-663: The restoration of abandoned metal mine workings, and sites where polychlorinated biphenyls have been dumped during manufacture and mitigation of ongoing coal mine discharges reducing the impact of contaminants in soils, water, or air. Contaminants such as metals, pesticides, solvents, explosives, and crude oil and its derivatives, have been mitigated in phytoremediation projects worldwide. Many plants such as mustard plants , alpine pennycress , hemp , and pigweed have proven to be successful at hyperaccumulating contaminants at toxic waste sites. Not all plants are able to accumulate heavy metals or organics pollutants due to differences in

1968-406: The root zone. Selenium (Se) and Mercury (Hg) are often removed from soil through phytovolatilization. Poplar trees are one of the most successful plants for removing VOCs through this process due to its high transpiration rate. Rhizofiltration is a process that filters water through a mass of roots to remove toxic substances or excess nutrients . The pollutants remain absorbed in or adsorbed to

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2016-430: The roots. This process is often used to clean up contaminated groundwater through planting directly in the contaminated site or through removing the contaminated water and providing it to these plants in an off-site location. In either case though, typically plants are first grown in a greenhouse under precise conditions. Biological hydraulic containment occurs when some plants, like poplars, draw water upwards through

2064-406: The soil beyond what the plants are able to translocate, causing potential leaching into the subsoil or groundwater. Examples of plants that are known to accumulate the following contaminants: Phytostabilization reduces the mobility of substances in the environment, for example, by limiting the leaching of substances from the soil . It focuses on the long term stabilization and containment of

2112-503: The soil into the roots and out through the plant, which decreases the movement of soluble contaminants downwards, deeper into the site and into the groundwater. Phytodesalination uses halophytes (plants adapted to saline soil) to extract salt from the soil to improve its fertility. Breeding programs and genetic engineering are powerful methods for enhancing natural phytoremediation capabilities, or for introducing new capabilities into plants. Genes for phytoremediation may originate from

2160-465: The term phytotransformation represents a change in chemical structure without complete breakdown of the compound. The term "Green Liver" is used to describe phytotransformation, as plants behave analogously to the human liver when dealing with these xenobiotic compounds (foreign compound/pollutant). After uptake of the xenobiotics, plant enzymes increase the polarity of the xenobiotics by adding functional groups such as hydroxyl groups (-OH). This

2208-409: The toxicity of the compounds, although many exceptions to the rule are seen. The increased polarity also allows for easy transport of the xenobiotic along aqueous channels. In the final stage of phytotransformation (Phase III metabolism), a sequestration of the xenobiotic occurs within the plant. The xenobiotics polymerize in a lignin -like manner and develop a complex structure that is sequestered in

2256-717: The transportation of logs, by tying them together into rafts and drifting or pulling them down a river. This method was very common up until the middle of the 20th century but is now used only rarely. Large rafts made of balsa logs and using sails for navigation were important in maritime trade on the Pacific Ocean coast of South America from pre-Columbian times until the 19th century. Voyages were made to locations as far away as Mexico, and many trans-Pacific voyages using replicas of ancient rafts have been undertaken to demonstrate possible contacts between South America and Polynesia . The type of raft used for recreational rafting

2304-444: The water for swimming, fishing and other recreation endeavors; spoil shoreline views; and pose a fire hazard. Phragmites also alters wetland biogeochemistry and affects both floral and faunal species assemblages, including potentially reducing nitrogen and phosphorus availability for other plants. Phragmites can drive out competing vegetation in two main ways. Their sheer height and density can deprive other plants of sunlight and

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