Typha Domingensis Research Articles

Effect of Typha domingensis cutting: response of benthic macroinvertebrates and macrophyte regeneration

Wetlands are important because they have high biodiversity and are considered, by environmental agencies, permanently protected areas due to their importance to conservation. In Southern Brazil the aquatic macrophyte Typha domingensis is harvested to be used in the manufacture of handicraft, being an important income source to small farmers. This work aims to test the cut effect of T. domingensis on benthic macroinvertebrates as well as on macrophyte regeneration. These phenomena were analyzed in small areas (1 m²) in a T. domingensis stand by comparing cut treatments and control treatments. Macroinvertebrate were sampled with a corer in the following time sequence after the cut event in both treatments: one day, 26 days, 60 days, 89 days, and 182 days. Macrophyte regeneration was monitored through monthly measurements at each treatment. The macroinvertebrate density did not differ between treatments (ANOVA, p < 0.05). Among the 23 taxa identified, Tubificidae was the only family to response to cut treatment. DCA showed an overlapping between treatments indicating a not clear pattern. The growth of T. domingensis shoots was not affected by the disturbance. Macrophyte regeneration was quick when comparing the treatments and statistical differences were found in one day after the disturbance and 26 days after the disturbance, whereas no differences were found in the remaining sampling dates (60, 89 and 182 days). Observing the macroinvertebrate response and the T. domingensis regeneration, our results suggest that sustainable use of this macrophyte is possible on a small scale.

Remocao de nitrogenio e fosforo de aguas residuarias de laticinios por sistemas alagados construidos operando em bateladas

This work presents the results of a study conducted for a period of seven months on the effectiveness of constructed wetland systems for the treatment of dairy wastewater aiming at removing, nitrogen and phosphorus. Six experimental systems were assembled with a net volume of 115 L using HDPE tanks, with length/width ratio of 2:1. In three of the systems, gravel 0 was used as substrate, while gravel 0 and sand was used in the three others, in the percentage of 80% and 20%, respectively. The systems were operated in batch cycles of 48 hours, applying 7.5 L of influent per cycle. Four of the experimental units were cultivated, and two kept as controls. The selected species chosen were the macrophytes, Typha domingensis and Hedychium coronarium. The removal efficiency concerning nitrogen compounds showed to be quite promising with values ranging from 29.4 to 73.4%, while phosphorus removal from the beds was lower, reaching efficiencies between 18.61 and 34.3%, considered good values, since the removal of these substances is quite difficult through conventional treatment.

Detrital Floc and Surface Soil Microbial Biomarker Responses to Active Management of the Nutrient Impacted Florida Everglades

Alterations in microbial community composition, biomass, and function in the Florida Everglades impacted by cultural eutrophication reflect a new physicochemical environment associated with monotypic stands of Typha domingensis. Phospholipid fatty acid (PLFA) biomarkers were used to quantify microbial responses in detritus and surface soils in an active management experiment in the eutrophic Everglades. Creation of open plots through removal of Typha altered the physical and chemical characteristics of the region. Mass of PLFA biomarkers increased in open plots, but magnitude of changes differed among microbial groups. Biomarkers indicative of Gram-negative bacteria and fungi were significantly greater in open plots, reflective of the improved oxic environment. Reduction in the proportion of cyclopropyl lipids and the ratio of Gram-positive to Gram-negative bacteria in open plots further suggested an altered oxygen environment and conditions for the rapid growth of Gram-negative bacteria. Changes in the PLFA composition were greater in floc relative to soils, reflective of rapid inputs of new organic matter and direct interaction with the new physicochemical environment. Created open plot microbial mass and composition were significantly different from the oligotrophic Everglades due to differences in phosphorus availability, plant community structure, and a shift to organic peat from marl-peat soils. PLFA analysis also captured the dynamic inter-annual hydrologic variability, notably in PLFA concentrations, but to a lesser degree content. Recently, use of concentration has been advocated over content in studies of soil biogeochemistry, and our results highlight the differential response of these two quantitative measures to similar pressures.

Vegetation dynamics in response to water inflow rates and fire in a brackish Typha domingensis Pers. marsh in the delta of the Colorado River, Mexico

The Cienega de Santa Clara is a 5600ha, anthropogenic wetland in the delta of the Colorado River in Mexico. It is the inadvertent creation of the disposal of brackish agricultural waste water from the U.S. into the intertidal zone of the river delta in Mexico, but has become an internationally important wetland for resident and migratory water birds. We used high resolution Quickbird and WorldView-2 images to produce seasonal vegetation maps of the Cienega before, during and after a test run of the Yuma Desalting Plant, which will remove water from the inflow stream and replace it with brine. We also used moderate resolution, 16-day composite NDVI imagery from the Moderate Resolution Imaging Spectrometer (MODIS) sensors on the Terra satellite to determine the main factors controlling green vegetation density over the years 2000–2011. The marsh is dominated by Typha domingensis Pers. with Phragmites australis (Cav.) Trin. Ex Steud. as a sub-dominant species in shallower marsh areas. The most important factor controlling vegetation density was fire. Spring fires in 2006 and 2011 were followed by much more rapid green-up of T. domingensis in late spring and 30% higher peak summer NDVI values compared to non-fire years (P<0.001). Fires removed thatch and returned nutrients to the water, resulting in more vigorous vegetation growth compared to non-fire years. The second significant (P<0.01) factor controlling NDVI was flow rate of agricultural drain water from the U.S. into the marsh. Reduced summer flows in 2001 due to canal repairs, and in 2010 during the YDP test run, produced the two lowest NDVI values of the time series from 2000 to 2011 (P<0.05). Salinity is a further determinant of vegetation dynamics as determined by greenhouse experiments, but was nearly constant over the period 2000–2011, so it was not a significant variable in regression analyses. It is concluded that any reduction in inflow volumes will result in a linear decrease in green foliage density in the marsh.

Modeling growth dynamics of Typha domingensis (Pers.) Poir. ex Steud. in Lake Burullus, Egypt

Southern Cattail (Typha domingensis) occurs everywhere in ditches and marshy places in Egypt and is one of the major components of vegetation stands along the shores of Lake Burullus close to the Deltaic Mediterranean coast. In our study, we applied a published Typha model to describe the growth production among the various organs of Southern Cattail in Lake Burullus, one of the Mediterranean eutrophic lakes, in order to answer the following questions: (1) Is the Typha model, originally designed for T. angustifolia and T. latifolia, suited to simulate the growth of Southern Cattail in the south Mediterranean region? and (2) How is biomass production of Southern Cattail distributed among the various plant organs? Above- and below-ground biomass of Southern Cattail was sampled monthly from February 2010 to October 2010 at three sites of Lake Burullus using three randomly distributed quadrats (each of 0.5m×0.5m) at each sampling site. Shoots started to grow in February, reached the maximum biomass of 6327±441gDWm−2 in July, and then rapidly decreased in the fall when they went to senescence stage, thereafter their growth ceased before fully dying off in the winter. The total below-ground biomass reduced to 941±152gDWm−2 in March due to the upward translocation for the initial growth of shoots, gradually increased to a maximum biomass of 2184±366gDWm−2 in July by downward translocation from shoots, then decreased afterwards in the winter to reach 1193±64gDWm−2 in October. Southern Cattail allocated approximately 52% of its total biomass to non-flowering shoots, 19% to flowering shoots, 22.5% to rhizomes and 6.5% to roots. The total above-ground biomass was 2.6 times that of the total below-ground biomass. General trends for above-ground biomass, such as the slow initial growth rate followed by a high growth rate, the timing of peak biomass, and the decline of biomass due to senescence, were successfully reproduced by the model. Many characteristics typical for the below-ground biomass, such as the reduction of rhizome biomass during the early growing season, and the increase in the rhizome biomass during the later period of the season, because of the translocation of materials from current photosynthesis and shoot dry matter, were also reproduced. In general, there was good agreement between the calculated results and field data although simulated results were slightly different from observations for below-ground biomass. Respiration of the above- and below-ground organs consumes a considerable amount of net photosynthetic materials 39% and 7%, respectively. The upward translocation of rhizome resources to form new shoots in February showed 8% to the gross production and the downward translocation afterwards showed a 22% to the gross production. In conclusion, Typha model is well-suited to simulate the growth of Southern Cattail stands in the south Mediterranean region and could be used in wetland management activities to predict the potential growth of Southern Cattail in Egyptian wetlands.

Rehabilitation options for inland waterways impacted by sulfidic sediments – Field trials in a south-eastern Australian wetland

The accumulation of significant pools of sulfidic sediments in inland wetlands and creeks is an emerging risk for the management of inland waterways. We used replicated plot trials to appraise the viability of various strategies for neutralizing oxidized, acidified sulfidic sediments in a highly degraded wetland. Of the twenty different treatments trialed only addition of calcium hydroxide or calcium carbonate, burning of wood, and planting of Phragmites australis, Typha domingensis and Atriplex nummularia into beds prepared with CaCO3 or P. australis and T. domingensis into beds of sediment and mulch, decreased total actual acidity (TAA) in the top 5 cm of sediment in the first two weeks following treatment. Only the calcium hydroxide treatments and planting of P. australis, T. domingensis and A. nummularia into beds prepared with CaCO3 decreased TAA for a longer period of time (6 months). None of the treatments, except the planting of P. australis into beds prepared with lime, decreased TAA in the 5-30 cm layer of sediments. Therefore, the only effective treatment appears to be the application of highly alkaline ameliorants which need to be transported to the site. A survey of the wetland was undertaken to estimate the total amount of actual and potential acidity stored in the wetland's sediment and overlying water and showed that up to 1200 tonnes of calcium carbonate would be required to neutralise all of the actual and potential acidity in the 10 ha wetland. However, neutralisation of the remaining water in the wetland (about 12.5 ML) would produce approximately 2750 m3 of metal rich sludge (approximately 100 tonnes dry weight) that would require separate disposal.

Effects of inundation on growth and nutrient allocation of six major macrophytes in the Florida Everglades

Understanding the effect of hydrological alterations on the establishment and growth of macrophytes is pivotal for restoring natural wetland plant communities and for managing constructed wetlands. Growth and nutrient storage of six native macrophytes commonly found in the Florida Everglades were studied under two inundation levels (20 and 60cm) in experimental mesocosms receiving inflow water with a low concentration of phosphorus (P). The six species, which were planted in soils collected from P-enriched areas, included one ridge species (Cladium jamaicense), three wet prairie species (Rhynchospora tracyi, Eleocharis elongata, and Eleocharis cellulosa), one slough species (Nymphaea odorata), and one fast spreading species (Typha domingensis).Inundation level greatly affected plant survivorship, growth, and nutrient allocation. The macrophytes differed substantially in their abilities to adapt to rising inundation level and in their adaptation strategies. N. odorata exhibited a substantial increase in both biomass and nutrient storage under rising inundation and had the largest accumulation of P and nitrogen among the six species studied. Aboveground biomass (A) and belowground biomass (B) allocation varied with species. Species with a lower A/B ratio under shallow inundation (N. odorata, E. cellulosa, and T. domingensis) adapted better to deeper inundation than those with higher A/B ratios (C. jamaicense, R. tracyi, and E. elongata). Adaptation to deeper inundation was achieved either by an increase in aboveground growth (E. cellulosa and T. domingensis) or by a simultaneous increase in both aboveground and belowground growth (N. odorata). Inability to adjust the A/B ratio in response to deeper inundation was characteristic of species that experienced high mortality (R. tracyi and C. jamaicense). The results of this study, which demonstrate differences in inundation tolerance and differences in mechanisms of inundation tolerance among common and diverse wetland macrophytes, will be useful for wetland restoration and management.

Heavy Metals Removal from Swine Wastewater Using Constructed Wetlands with Horizontal Sub-Surface Flow

The removal efficiency of Cu and Zn from swine wastewater was evaluated as effected by three variables: the hydraulic retention time (HRT) (24, 48, 72 and 96 hours), two different plant species (Typha domingensis Pers. and Eleocharis cellulosa) and two different sizes of filter media (5 and 15 mm) using a horizontal sub-surface flow constructed wetland. From the results, a significant difference was observed in the removal efficiency of Cu and Zn with respect to different hydraulic retention times. The best results were obtained in the HRT of 96 hours for Zn where 96% removal of Zn with Typha domingensis Pers. specie with gravel of 15 mm (experimental unit 6) was achieved. For Cu, at 72 hours of HRT, the efficiency was nearly 100% in five of the six study units (1, 2, 3, 5 and 6). In contrast, in experimental unit 4 with gravel of 15 mm and without plants, only 86% Cu removal was achieved.

手賀沼のマコモ帯とヒメガマ帯で採集された魚類とその安定同位体比

手賀沼のマコモ帯とヒメガマ帯で採集された魚類とその安定同位体比

Uptake of Ag, Co and Ni by the Organs of &amp;lt;i&amp;gt;Typha domingensis&amp;lt;/i&amp;gt; (Pers.) Poir. ex Steud. in Lake Burullus and Their Potential Use As Contamination Indicators

The concentrations of Ag, Co and Ni in the sediments and the different organs of Typha domingensis from Lake Burullus, Egypt, were investigated monthly from February to September 2010 to evaluate the aquatic environment quality of the lake and to test the suitability of these organs for bio-indicating of sediment metals. The sediment heavy metals were found to decrease in the order of Ni > Co > Ag. The sediment contents of Ag were about 45 times above the worldwide range. On the other hand, Co concentrations were below the reference ranges of United States and Chinese soils. The heavy metals bioaccumulation decreased according to the order of rhizome > root > leaf for Ag; and root > rhizome > leaf for Co and Ni. It was found also that, T. domingensis had no significant differences in heavy metals concentrations over time. The transfer factors of Ag, Co and Ni from sediment to below-ground organs were smaller than one. Co had the maximum transport from below-ground to above-ground organs, while Ag had the minimum. There was a significant linear correlation between the concentration of Ag in root of T. domingensis and that in sediment. This result suggested that T. domingensis can be regarded as bio-indicator for Ag pollution of Lake Burullus.

Recent Cattail Expansion and Possible Relationships to Water Management: Changes in Upper Taylor Slough (Everglades National Park, Florida, USA)

Recent appearance of cattail (Typha domingensis) within a southern Everglades slough-Upper Taylor Slough (Everglades National Park)-suggests ecosystem eutrophication. We analyze water quality, nutrient enrichment, and water management operations as potential drivers of eutrophication in Upper Taylor Slough. Further, we attempt to determine why surface water phosphorus, a parameter used commonly to monitor ecosystem health in the Everglades, did not serve as an early warning for eutrophication, which has broader implication for other restoration efforts. We found that surface water total phosphorus concentrations generally were below a 0.01 mg L(-1) threshold determined to cause imbalances in flora and fauna, suggesting no ecosystem eutrophication. However, assessment of nutrient loads and loading rates suggest Upper Taylor Slough has experienced eutrophication and that continued total phosphorus loading through a point-source discharge was a major driver. These nutrient loads, combined with increases in hydroperiods, led to the expansion of cattail in Upper Taylor Slough. We recommend other metrics, such as nutrient loads, periphyton and arthropod community shifts, and sediment core analyses, for assessing ecosystem health. Monitoring surface water alone is not enough to indicate ecosystem stress.

(2S)-Naringenin from Typha angustata inhibits vascular smooth muscle cell proliferation via a G0/G1 arrest

Ethnopharmacological relevanceTypha angustata is used in traditional Chinese medicine for a variety of clinical disorders. Its pharmacological actions include beneficial effects on hyperlipidemia and myocardial infarction, as well as labor-inducing and antibacterial effects. Aim of the studyWe investigated the mechanism underlying the ability of (2S)-naringenin, an active compound from Typha angustata, to inhibit the proliferation of vascular smooth muscle cells (VSMCs). Materials and methodsAfter measuring the antiproliferative effect of (2S)-naringenin on VSMC proliferation using cell proliferation and viability assays, the possible involvement of a signaling pathway associated with platelet-derived growth factor receptor β (PDGF-Rβ), extracellular signal regulated kinase 1/2 (ERK1/2), phosphatidylinositol 3-kinase (PI3K)-linked protein kinase B (Akt/PKB), or phospholipase C-γ1 (PLCγ1) was investigated by immunoblotting. Moreover, the effect of (2S)-naringenin on DNA synthesis and the cell cycle was examined using a [3H]-thymidine incorporation assay and flow cytometry. Results(2S)-Naringenin significantly inhibited PDGF-BB-induced VSMC proliferation in a concentration-dependent manner, but did not affect signaling pathways associated with PDGF-Rβ, Akt/PKB, ERK1/2, or PLCγ1. However, (2S)-naringenin suppressed DNA synthesis via a G0/G1 cell cycle arrest. Accordingly, the expression of cyclins D1 and E and cyclin-dependent kinases 2 and 4 was inhibited in a concentration-dependent manner; moreover, the phosphorylation of retinoblastoma protein was suppressed. ConclusionsOur results show that (2S)-naringenin inhibited the PDGF-BB-induced proliferation of VSMCs via a G0/G1 arrest; thus, (2S)-naringenin may be valuable as a therapeutic agent for managing atherosclerosis and/or vascular restenosis.

Fire-mobilized nutrients from hydrophyte leaves favor differentially Typha domingensis seedling growth

In wetlands, altered disturbance regimes can change species composition and favor the expansion of invasive species. In Central Mexico, Typha domingensis expands after fires to colonize areas previously dominated by other natives, but the mechanisms are unknown. To explore if the invasion is facilitated by nutrient release after fire, we tested the effect of ash from Schoenoplectus americanus and T. domingensis plants on the growth of T. domingensis seedlings. Schoenoplectus ash had higher concentration of soluble phosphates (0.68±0.23mg/g) than Typha ash (0.36±0.08mg/g). At two months Typha seedlings were taller (48±8cm) in the treatment with Schoenoplectus ash added than in either the treatment with Typha ash (29±7cm) or in the control (25±6cm). Aboveground biomass (1.03±0.42g, 0.36±0.17g, 0.27±0.11g) and belowground biomass (0.65±0.24g, 0.32±0.11g, 0.27±0.11g) showed the same trends. Typha seedlings fertilized with Schoenoplectus ash had the lowest root:shoot ratios, but the largest rhizomes (dry weight 0.07±0.03g), followed by those fertilized with Typha ash (0.04±0.01g) and control plants (0.03±0.01g). These results show that T. domingensis responds to increased phosphate availability from ash of other species by growing larger and allocating more to storage tissues. We conclude that fire promotes the spread of Typha by facilitating seedling growth especially in areas dominated by S. americanus.

Factorial design for optimizing the removal of aluminium from aqueous solutions by adsorption on Typha domingensis phytomass

Typha domingensis phytomass is used as a biosorbent for aluminium ions removal from aqueous solution. A full 23 factorial design of experiments is used to obtain the best conditions of biosorption of Al3+ from water solutions. The three factors screened are temperature, pH, and biosorbent dosage. Two levels for each factor are used; pH (2.5 and 6.0), temperature (25 and 45°C), and phytomass loading weight (0.5 and 1 g/50 ml). Batch experiments are carried out using 50 ml solutions containing 7 mg/L Al3+ simulating its concentration in a real wastewater effluent. Aluminium concentration in solutions is determined using ICP-OES; the removal percentages of aluminium are then evaluated. The results are analyzed statistically using the Minitab 15 statistical software to determine the most important factors affecting aluminium removal. The results revealed that pH is the most significant factor affecting aluminium ions uptake onto Typha phytomass.

Invader versus natives: Effects of hydroperiod on competition between hydrophytes in a tropical freshwater marsh

The La Mancha freshwater marsh (Veracruz, Mexico) has heterogeneous water and ground levels; spatial variation that is reflected in its vegetation's distribution. The invasive grass Echinochloa pyramidalis grows in relatively dry areas, whereas native species, including Sagittaria lancifolia and Typha domingensis, dominate the wettest parts of the marsh. To determine the effects of hydroperiod on competition between the invasive and native hydrophytes, we designed a field experiment based on replacement series of pairs of species under different hydroperiod treatments. The results demonstrate that E. pyramidalis performs best under permanently dry conditions. Under almost permanently flooded conditions, S. lancifolia produced more cover than the invasive grass did, while T. domingensis produced cover and biomass similar to those of the invasive species. Besides the effects of the dominance of E. pyramidalis over the native species, this dominance produced changes in the soil level on a microtopographic scale. Plots under permanently dry conditions and with high E. pyramidalis cover exhibited a slight increase in surface height. We conclude that La Mancha's weed invasion is a consequence of the deliberate introduction of E. pyramidalis into the relatively dry areas of the wetland. This weed, a non-indigenous grass, has gradually advanced towards the wetter areas, changing the marsh's topography and hydroperiod in the process, and inducing changes in species composition.

Modeling ecosystem responses to prescribed fires in a phosphorus-enriched Everglades wetland: II. Phosphorus dynamics and community shift in response to hydrological and seasonal scenarios

Fires have been proposed as one of the important options to manage and restore degraded wetlands through changing nutrient regimes; however, their effects on nutrient dynamics and community shift have not been studied sufficiently. In this study, wetland ecosystem model (WEM) was enhanced by incorporating plant competition, and applied to a moderately phosphorus-enriched area in the Everglades with a mixed cattail ( Typha domingensis) and sawgrass ( Cladium jamaicense) community. The WEM model was first validated by comparing simulated results against field observations, and applied to evaluate the effects of multiple surface fires on phosphorus (P) dynamics and the structure of a mixed cattail and sawgrass community. The simulation results indicated that a single fire could substantially alter the P dynamics in surface water for nearly two months, while multiple fires within a two-year interval, regardless of season, could cause a shift of plant community structure, expressed as a desirable increase in sawgrass and a decrease in cattail. After the successive fires, the biomass and composition of recovering plant community did not reach the pre-fire level within six years. Regardless of season, the fires conducted under the low-water-depth condition, compared with the high-water-depth condition, yielded stronger effects on P dynamics in soil, surface water, porewater, and on the plant community composition. Regardless of water depths, February fires, compared to July fires, caused a stronger shift in plant community structure expressed as a decrease in cattail biomass and an increase in sawgrass biomass. Regardless of seasons and water depths, fires caused a short-term increase and long-term decline in total phosphorus (TP) concentration in soil, surface water, and porewater. These results might suggest that the winter fires, under low-water-depth appear to be the best fire management option for accelerating recovery of a cattail-dominated wetland to a sawgrass-dominated wetland. In the proposed fire and hydrological regimes, four fires at two-year intervals generated the maximum suppressing effect on cattail, and the maximum stimulating effect on sawgrass. The results of this study support the concept that fire could be used as an option to manage plant composition and dominance. However, further process-based studies are necessary to explore additional fire regimes and hydrological scenarios to maintain sawgrass over cattail.

Effect of pollen from Typha angustata on hydrogen peroxide induced toxicity in osteoblastic MC3T3‐E1 cells

Typha angustata is a traditional Chinese medicine, commonly used for a variety of clinical disorders, including atherosclerosis and wound healing. In the present study, the protective effects of T. angustata pollen extract (TE) on the response of osteoblast to oxidative stress were evaluated. Osteoblastic MC3T3-E1 cells were incubated with H(2)O(2) and/or TE, and markers of osteoblast function and oxidative damage were examined. TE treatment significantly (P < 0.05) reversed the cytotoxic effect of H(2)O(2) and this effect was blocked by ICI182780, suggesting that TE's effect might be partly involved in estrogen action. TE significantly (P < 0.05) increased collagen content, alkaline phosphatase activity, calcium deposition of osteoblasts in the presence of H(2)O(2) and these effects were blocked by rottlerin and PD98059, suggesting that the induction of differentiation by TE is associated with increased activation of protein kinase C and ERK. Moreover, H(2)O(2)-induced reduction of osteocalcin was significantly recovered in the presence of TE. Pretreatment with TE also decreased the increase in receptor activator of nuclear factor-kB ligand, malondialdehyde, and protein carbonyl induced by H(2)O(2). These results suggest that the pollen of T. angustata may be useful for the protection of H(2)O(2)-induced oxidative damage and dysfunction in osteoblasts.

Phytoremediation of industrial wastewater potentiality by Typha domingensis

Phytoremediation is increasingly receiving attention as a cost effective technique that uses plants to remediate contaminants from wastewater, soil and sediments. In this study, the ability of Typha domingensis to uptake heavy metals as well as its potential application for phytoremediation was assessed. Pollutant elements concentrations were measured in samples of wastewater, sediments and Typha domingensis collected from industrial wastewater ponds, El-Sadat city, Egypt. This study specifically focused on the capacity of Typha domingensis to absorb and accumulate aluminum, iron, zinc and lead. Results indicated thatTypha domingensis was capable of accumulating the heavy metal ions preferentially from wastewater than from sediments. The accumulation of metals in plant organs attained the highest values in roots, rhizomes and old leaves. Rhizofiltration was found to be the best mechanism to explain Typha domingensis phytoremediation capability.

Effects of eutrophication and Typha domingensis Pers on methanogenesis in tropical constructed wetland

AIM: Constructed wetlands (CWs) have shown to be an efficient way for removing nutrients from wastewaters. However, a negative effect is the emission of greenhouse gases (GHGs). Methane (CH4) is a GHG released from the organic matter degradation under anaerobic conditions by methanogenic bacteria. In CWs, the excessive nutrient inputs may stimulate both primary production and methanogenesis and then affect the overall cost-benefit balance of this system. Here, we assessed the role of cattail stands (Typha domingensis Pers) on CH4 concentrations in eutrophic and mesotrophic constructed wetlands. METHODS: CWs were filled with water and sediment colonized by the aquatic macrophyte Typha domingensis Pers from two tropical freshwater lakes, one mesotrophic and another eutrophic. RESULTS: Our results showed consistently higher CH4 concentrations in waters and sediment in the eutrophic CWs than in the mesotrophic CWs (two times), indicating a positive influence of eutrophication on methanogenesis. CONCLUSION: In conclusion, CH4 emissions from tropical CWs demand to be considered or even mitigated in any use of this system.

Heavy metal biomonitoring and phytoremediation potentialities of aquatic macrophytes in River Nile

The concentrations of Cd, Cu, Pb, and Zn in sediments, water, and different plant organs of six aquatic vascular plant species, Ceratophyllum demersum L. Echinochloa pyramidalis (Lam.) Hitchc. & Chase; Eichhornia crassipes (Mart.) Solms-Laub; Myriophyllum spicatum L.; Phragmites australis (Cav.) Trin. ex Steud; and Typha domingensis (Pers.) Poir. ex Steud, growing naturally in the Nile system (Sohag Governorate), were investigated. The aim was to define which species and which plant organs exhibit the greatest accumulation and evaluate whether these species could be usefully employed in biomonitoring and phytoremediation programs. The recorded metals in water samples were above the standard levels of both US Environmental Protection Agency and Egyptian Environmental Affairs Agency except for Pb. The concentrations of heavy metals in water, sediments, and plants possess the same trend: Zn > Cu > Pb > Cd which reflects the biomonitoring potentialities of the investigated plant species. Generally, the variation of heavy element concentrations in water and sediments in relation to site and season, as assessed by two-way repeated measured ANOVA, was significant (p < 0.05). However, insignificant variations were observed in the concentrations of Pb and Cd in sediments in relation to season and of Cu and Zn in relation to site. Results also showed that the selectivity of the heavy elements for the investigated plants varied significantly (p < 0.05) with species variation. The accumulation capability of the investigated species could be arranged according to this pattern: C. demersum > E. crassipes > M. spicatum > E. pyramidalis > T. domingensis > P. australis. On the basis of the element concentrations, roots of all the studied species contain higher concentrations of Cu and Zn than shoots while leaves usually acquire the highest concentrations of Pb. Cd concentrations among different plant organs are comparable except in M. spicatum where the highest Cd concentrations were recorded in the leaves. Our results also demonstrated that all the studied species can accumulate more than 1,450-fold the concentration of the investigated heavy elements in water rendering them of interest for use in phytoremediation studies of polluted waters. Given the absence of systematic water quality monitoring, heavy elements in plants, rather than sediments, provide a cost-effective means for assessing heavy element accumulation in aquatic systems during plant organ lifespan.