Plant invasion and nutrient enrichment because of anthropogenic landscape modifications seriously threaten native plant community diversity in aquatic and wetland ecosystems. It is poorly understood, ...however, whether these two disturbances interact with the functional identity of recipient native plants to drive community change. We performed combined studies in the fields and greenhouse to examine whether nutrient enrichment may trigger the invasion of Phragmites australis in wetlands through competitive advantage over native Melaleuca ericifolia. Chemical characterizations of rhizosphere water were distinguished in two different nutrient enriched wetlands associated with and without Phragmites over the seasons. Significant changes in rhizosphere water were observed in invaded area compared to uninvaded area at both sites. High nitrogen (NO3−), phosphorous (PO43−), dissolved organic carbon, phenolics contents, with low pH were found in invaded areas compared to uninvaded areas. Total biomass of Phragmites was positively regressed with rhizosphere water nitrogen (NO3−) and phosphorous (PO43−) content. Nutrient addition significantly enhanced the growth and competitive ability of Phragmites over Melaleuca. In contrast, Melaleuca was significantly less competitive than Phragmites. There was a significantly positive correlation between the growth of Phragmites grown alone and its competitive ability. The findings in greenhouse studies coupled with characteristics of Phragmites and its' rhizosphere chemistry in the nutrient enriched fields suggest that nutrient enrichment may enhance Phragmites invasion through correspondingly increasing growth and maintaining inherent competitive advantages of Phragmites. Nutrient management could limit the vigorous growth of Phragmites in wetlands and thereby reduce invasion through competitive advantages over natives, which might have important management implications for wetland managers.
Fig. Action and Effect of invasive species in wetland along nutrient gradient. Display omitted
•Significant seasonal changes in rhizosphere chemistry were observed in invaded areas.•Nutrient availability was significantly higher in rhizosphere of the invaded sites.•Biomass of Phragmites australis was positively regressed to rhizosphere nutrient.•Nutrient enrichment enhanced growth and competitiveness of Phragmites over natives.•Nutrient enrichment may increase the risk of Phragmites invasion in wetlands.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Antibiotic pollution has become a hot issue worldwide, which has toxic effects on plants and even threatens human health. As a common wetland plant, the tolerance mechanism of Phragmites australis to ...antibiotics is rarely reported. In this study, we investigated the enrichment characteristics and biological response of P. australis to sulfamethoxazole (SMZ) and ofloxacin (OFL) residues, which are common in the environment. We found that the simulated concentration of antibiotics far exceeded the current level of antibiotic residues in the water environment, but it did not significantly inhibit the growth of P. australis. At 1 mg L−1, OFL and SMZ significantly increased the biomass of P. australis, which was mainly related to the improvement of root activity and photosynthetic efficiency, but the duplex treatment (SMZ + OFL) did not significantly stimulate the growth of reeds. OFL could significantly reduce the accumulation of reactive oxygen species (ROS) in P. australis. When OFL was 1 mg L−1, compared with control, superoxide anion and H2O2 were reduced by 11.19% and 10.76%, respectively, which was mainly related to the improvement of membrane stability. SMZ and SMZ + OFL had no significant effect on ROS, but they significantly increased antioxidant enzyme activity. SMZ and OFL could increase soil invertase, urease, and protease activities, and the tested antibiotics had no significant effect on the Shannon-Wiener index of soil microorganisms. The accumulation of antibiotics within tissues could be ranked as root > leaf > stem, and the accumulation and transport of OFL were higher than those of SMZ.
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•Low does OFL reduced MDA content in P. australis.•Low dose OFL improved root activity and Shannon-Wiener index.•SMZ + OFL significantly increased antioxidant enzyme activity.•The accumulation and transport ability of P. australis to OFL was higher than SMZ.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Water shortage and excessive use of water resources in arid and semi-arid regions, such as Iran, highlights the importance of using treated wastewater, especially for the highly demanding ...agricultural sector. Constructed wetlands (CWs) are among green technologies that offer an efficient and cost-effective wastewater treatment. This study investigates the complementary treatment of effluent from the Fooladshahr wastewater treatment plant, Isfahan, Iran, using pilot-scale CWs with horizontal (H-CW) and horizontal-vertical flow (HV-CW). The performance of two substrates, pumice and gravel, and the effect of using plants (Phragmites australis) was compared. Maximum removal efficiencies of total suspended solids (TSS) and biochemical oxygen demand (BOD5) were observed in the case of unplanted and planted HV-CW with pumice bed, respectively. In the case of gravel bed, planted H-CWs demonstrated maximum chemical oxygen demand (COD) removal efficiency. The highest mean outflow concentrations for TSS, BOD5 and COD were obtained in unplanted H-CW with pumice bed, likely due to shorter retention times compared to HV-CWs, as well as due to the absence of plants providing the required physicochemical and biological conditions for high performance treatment. Phosphate (PO43−) removal efficiency demonstrated seasonal dependency, where the highest values were obtained in warm seasons. In the case of fecal coliforms (FC), no significant differences were observed between the studied HV-CWs during the whole study period. Based on our results, planted H-CW with gravel bed provided an optimum removal efficiency while requiring a smaller footprint and lower expenditure than HV-CWs. This study demonstrates the application of CWs as an affordable solution for treating domestic wastewater for various reuse application in developing countries with water crisis, such as Iran.
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•Stabilization pond effluents were improved using hybrid constructed wetlands (CWs).•The effect of pumice and gravel was compared in combination or absence of plants.•The removal efficiency of TSS, BOD5, COD and PO4 was investigated.•Planted gravel CW showed optimum removal efficiency with lowest footprint and cost.•The PO4 removal efficiencies is shown to be seasonal (cold or warm) dependent.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This study aimed to evaluate the potential of a salt marsh plant and its rhizosphere microorganisms for the removal of two pharmaceutical compounds, bezafibrate and paroxetine, from estuarine ...environment. Plants were exposed for 7 days to a simplified estuarine medium, elutriate solution with or without sediment, doped with bezafibrate or paroxetine. Tests were done in absence and presence of nutrients or copper.
Phragmites australis (Cav.) Trin. Ex Steud
, alone or with the sediment microbial communities, contributed for pharmaceuticals removal. In the presence of
P. australis
, for paroxetine a 65% removal was observed. Removal increased up to 90% when sediment was present. For bezafibrate, removals reached ca. 47% in
P. australis
presence, increasing to ca. 70% when nutrients were added to the medium, indicating a good nutritional state can contribute for a higher compound removal. When Cu was added, 75% removal for bezafibrate and 95% removal for paroxetine were observed indicating the metal might influence the removal of the pharmaceuticals. Overall, the plant and its rhizosediments and associated microorganisms showed potential for pharmaceuticals removal from estuaries, eventually degrading the selected compounds, a feature requiring more research. Results indicate that phytoremediation could be a viable option for eliminating/diminishing the environmental impact of pharmaceutical compounds in estuarine areas.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Measuring specific ion fluxes from different regions of the root under practical physiological conditions is crucial for understanding metal uptake mechanisms by plants. We developed and tested a ...neutral carrier-based liquid-membrane Pb super(2+) and Cu super(2+) ion selective microelectrode (ISME) to investigate ion-transport processes along the roots of three common wetland plant species. The Pb super(2+) and Cu super(2+) ISME exhibited a Nernstian response with Pb super(2+) and Cu super(2+) activities as low as 1.0 nM and 1.0 mu M in deionized water and simulated soil solution, respectively. Phragmites australis had a region of Cu super(2+) release for approximately the first 200 mu m, while it exhibited Pb super(2+) and Cd super(2+) outward net flux up to the first 500 mu m. Although in older sections of the root of Phragmites australis there were areas of influx of Cu super(2+), Pb super(2+) and Cd super(2+), the overall influx was much smaller than that of Typha latifolia or Canna indica. Such a reduced uptake and/or an increased efflux of metal ions across the root-cell plasma-membrane might explain the higher resistance of Phragmites australis to metals, at least in part. The Pb super(2+) and Cu super(2+) ISMEs are shown to permit detailed investigation of heavy-metal ion transport in plant roots, especially for plants used for phytoremediation.
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BFBNIB, DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NMLJ, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The objective of this study was to investigate the relationship between Cd(2+)/NH4(+) sorption and physicochemical properties of biochars produced from different wetland plants. Biochars from six ...species of wetland plants (i.e., Canna indica, Pennisetum purpureum Schum, Thalia dealbata, Zizania caduciflora, Phragmites australis and Vetiveria zizanioides) were obtained at 500°C and characterized, and their sorption for ammonium and cadmium was determined. There were significant differences in elemental composition, functional groups and specific surface area among the biochars derived from different wetland plant species. Sorption of ammonium and cadmium on the biochars could be described by a pseudo second order kinetic model, and the simple Langmuir model fits the isotherm data better than the Freundlich or Temkin model. The C. indica derived biochar had the largest sorption capacity for NH4(+) and Cd(2+), with a maximum sorption of 13.35 and 125.8mgg(-1), respectively. P. purpureum Schum derived biochar had a similar maximum sorption (119.3mgg(-1)) for Cd(2+). Ammonium sorption was mainly controlled by cation exchange, surface complexation with oxygen-containing functional groups and the formation of magnesium ammonium phosphate compounds, whereas for Cd(2+) sorption, the formation of cadmium phosphate precipitates, cation exchange and binding to oxygen-containing groups were the major possible mechanisms. In addition, the sorption of ammonium and cadmium was not affected by surface area and microporosity of the biochars.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
River carrying antibiotics from upstream posed serious threats to receiving lake, and plants might had effects on antibiotics. Therefore, samples of waters, sediments and tissues of cultivated and ...wild Phragmites australis were collected to analyse antibiotics fate and ecological risks (RQs) in Zaozhadian Lake. Our results revealed that the total antibiotics showed an increasing tendency in surface/pore water and P. australis tissues and a decreasing tendency in overlying water and sediments from the lake entrance to the centre. The bioaccumulation factors (BAFs) of two sulfonamides (SAs) and three quinolones (QNs) increased in sediments and decreased in those of erythromycin in pore water from Site 1 to Site 11. Three QNs and two tetracyclines (TCs) were dominant antibiotics in pore water/sediment and surface/overlying water respectively. Higher levels of two SAs in surface/pore water and two macrolides (MAs) in overlying/pore water and sediments were observed in the wild P. australis region, while higher values of two TCs in overlying/pore water and three QNs in sediment were observed in the cultivated P. australis region. Higher BAFs of SAs and QNs in sediments were observed in the cultivated and wild P. australis region respectively. The RQs of oxytetracycline and two MAs posed moderate risks in surface/overlying water from more than 50% of sampling sites. Norfloxacin exhibited moderate RQ and low ∑RQ levels in sediments, and showed high risk in pore water. Our findings imply that much more attention should be given to the antibiotics from river inputs and management normatives to control antibiotic pollution.
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•Norfloxacin posed higher levels ecological risk in cultivated/wild plant region.•River runoff influenced the bioaccumulations and ecological risks of antibiotics.•Quinolones and tetracyclines were main antibiotics in wild/cultivated plant region.•Ciprofloxacin and norfloxacin shown higher concentration in cultivated/wild plants.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
We examined stable carbon and nitrogen isotope ratios for a large variety of consumers in intertidal and subtidal habitats, and their potential primary food sources i.e., microphytobenthos (MPB), ...phytoplankton, and Phragmites australis in a coastal bay system, Yeoja Bay of Korea, to test the hypothesis that the transfer of intertidal MPB-derived organic carbon to the subtidal food web can be mediated by motile consumers. Compared to a narrow delta13C range (-18 to -16ppt) of offshore consumers, a broad delta13C range (-18 to -12ppt) of both intertidal and subtidal consumers indicated that 13C-enriched sources of organic matter are an important trophic source to coastal consumers. In the intertidal areas, delta13C of most consumers overlapped with or was 13C-enriched relative to MPB. Despite the scarcity of MPB in the subtidal, highly motile consumers in subtidal habitat had nearly identical delta13C range with many intertidal foragers (including crustaceans and fish), overlapping with the range of MPB. In contrast, delta13C values of many sedentary benthic invertebrates in the subtidal areas were similar to those of offshore consumers and more 13C-depleted than motile foragers, indicating high dependence on phytoplankton-derived carbon. The isotopic mixing model calculation confirms that the majority of motile consumers and also some of subtidal sedentary ones depend on intertidal MPB for more than a half of their tissue carbon. Finally, although further quantitative estimates are needed, these results suggest that direct foraging by motile consumers on intertidal areas, and thereby biological transport of MPB-derived organic carbon to the subtidal areas, may provide important trophic connection between intertidal production and the nearshore shallow subtidal food webs.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Highly efficient sequestration of carbon into soil by plants is crucial to wetland ecosystems under rising atmospheric CO2. The carbon sequestration ability of wetland can be roughly evaluated from ...the amount of carbon fixed through plant's photosynthesis, but the decomposition properties of plant litter returning to soil are also essential to its evaluation. We examined litter decomposition of Phragmites australis (P. australis) and Spartina alterniflora (S. alterniflora), two dominant plants from Jiuduansha wetland in the Yangtze River estuary, returned to soil in-situ and ex-situ, to clarify their effect on soil respiration and carbon sequestration efficiency. Both mass and carbon content of S. alterniflora were lost faster than P. australis when their plant litters were returned to soil. Soil type exerted a significant effect on litter decomposition but not on plant ranking for decomposition rate (k). High moisture and low nitrogen content in the wetland soils resulted in the lower decomposition rates of litter, compared with inland soils. Litter properties were determining factors in ranking of decomposition rate, in which the k was negatively correlated with the lignin/N and C/N ratios, and positively correlated with the initial nitrogen content. P. australis had low nitrogen content, high lignin/N and C/N ratios, so it had the lower decomposition rate and soil respiration. Combine the plant biomass, litter decomposition and soil respiration, P. australis wetland possesses the higher carbon sequestration ability in the Yangtze River estuary than S. alterniflora wetland.
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•The decomposition of wetland plant litters in soil was studied in-situ and ex-situ.•The litter decomposition of P. australis is slower than S. alterniflora.•The lower nitrogen and N/C ratio in P. australis lead to its slower decomposition.•C sequestration ability of wetland depends on its biomass, k and SR.•P. australis wetland has higher C sequestration ability in the Yangtze River estuary.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
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