The design, operation, pollutant removal as well as hydraulic modeling of wetland systems for wastewater treatment can be improved by better understanding and simulating the evapotranspiration ...process. To this purpose, two experiments were carried out in Northern (Veneto region) and Southern (Sicily region) Italy to measure evapotranspiration (ET) and determine the crop coefficient of
Phragmites australis (Cav.) Trin. using the FAO 56 approach. The experimental set-up consisted of a combination of vegetated and unvegetated plastic tanks (Veneto) or pilot sub-surface flow beds (Sicily). The ET values were obtained by measuring the amount of water needed to restore the initial volume in the tanks and in the beds after a certain period. All the needed climatic variables were measured and taken into account in the ET measurements. In the two experimental sites cumulative reference evapotranspiration (ET
0) was similar to the cumulative ET measured in the control tanks and beds (without vegetation, ET
con), while ET measured for
P. australis (ET
phr) was significantly higher, underlining the strong effect of vegetation. From June 2009 to September 2009 the cumulative ET
0, ET
con and ET
phr in Veneto were 455, 424 and 3048
mm, in Sicily 653, 556 and 3899
mm, respectively. The plant coefficient trend of
P. australis (
K
p) estimated in Veneto was similar to that in Sicily, suggesting that the role of the plant in dispersing water is similar under different environmental conditions. Additional measurements made in the Veneto plant showed that
K
p assumes different patterns and values in relation to plant age and growth stage. These results highlight the importance of the plants in regulating water losses from a wetland system, above all from small-scale constructed wetlands where the effect of the advection in ET rates is evident.
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Elevated atmospheric carbon dioxide (eCO2) concentrations and nitrogen (N) enrichment are known to enhance plant productivity and invasion. However, the implications of their interactive effects for ...plant productivity are not well understood, especially at the stand scale, presumably because morphological and physiological responses to these global change factors are rarely studied together in the field or assessed at the stand level.
We first determined how leaf‐level morphological and physiological traits responded to factorial combinations of ambient and elevated CO2 and N. We collected trait data from the model invasive species Phragmites australis (common reed) that were measured over 3 years in a long‐term global change field experiment. We then combined the trait data and additional descriptions of P. australis canopies in a simulation model of carbon assimilation to determine how morphology and physiology contribute to P. australis’ stand‐scale productivity.
At the leaf level, we found that light‐saturated rates of photosynthesis were strongly stimulated by eCO2 (37%) and that this effect was enhanced by increasing salinity. N had a smaller effect (17% stimulation) on physiological responses than eCO2, but leaf morphological traits responded primarily to N; plant height increased by 27% and leaf area increased by 47%.
Stand‐scale simulations demonstrated that that morphological and physiological adjustments induced approximately additive responses when P. australis experienced both eCO2 and N enrichment. The simulations also indicated that morphological changes (which were primarily associated with canopy size) influenced stand‐scale carbon assimilation more than physiological changes. Moreover, 97% of the N response was due to changes in morphology, whereas 62% of the eCO2 response was caused by physiological shifts.
Our analysis indicates that morphological and physiological trait responses to elevated CO2 and nitrogen are likely to enhance the productivity of P. australis in complementary ways, potentially accelerating its invasion in North America. Furthermore, our data suggest that changes in morphological traits may have a greater influence on carbon gain than leaf‐level physiology under near‐future environmental conditions. Our study also highlights the importance of accounting for both morphological and physiological responses when attempting to infer global change responses from leaf‐level data.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NMLJ, NUK, OILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
Invasive species are especially problematic when introduced into ecosystems with native congeners. The extent to which niches overlap in space determines whether the introduced species threatens the ...native one or the native species can escape competition or the effect of control. We compared the spatial distribution in relation to landscape and land-use/ land-cover variables of introduced and native Phragmites australis (common reed) in a landscape of protected freshwater wetlands in Quebec, Canada. Results showed that the wetlands still serve as refuges for native P. australis. At this stage of invasion, native and introduced P. australis occupy distinct spatial niches, the more abundant native type in low marsh and areas of lesser human impacts, the introduced one closer to roads and drier land covers. For now, native P. australis largely escapes competition, and the lack of spatial overlap could reduce opportunities for hybridization. Our study also suggests that invasion foci could still be controlled without endangering the native type. Whether the heterogeneous wetland conditions and the different spatial niches will be sufficient to allow long-term coexistence of native and introduced P. australis remains to be seen, but the situation needs to be closely monitored, especially in wetlands protected for biodiversity conservation.
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BFBNIB, GIS, IJS, KISLJ, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
Plants play a cardinal role in removing various pollutants through the synergistic interaction with filling materials and microbes of constructed wetlands (CWs). However, the information regarding ...the selection of plant species to remove pharmaceutically active compounds (PhACs) is not adequate. The present study attempted to select an appropriate plant species for CWs, considering their characteristics and physiological response to PhACs. In this regard, batch hydroponics studies were carried out to assess the removal, fate, and antioxidative response of carbamazepine (CBZ) in four wetland plant species (Canna indica, Colocasia esculenta, Phragmites australis, and Chrysopogon zizanioides). The specific uptake potential of CBZ (in terms of plant dry biomass) was found to be in the order: C. indica (14.48 mg/g) >P. australis (11.71 mg/g) >C. esculenta (8.67 mg/g) >C. zizanioides (6.04 mg/g). The results showed that exposure to CBZ (0–30 days) caused an accumulation of reactive oxygen species (ROS) in the plant tissues, causing a decline in chlorophyll content, root activity, and increased oxidative stress. However, the selected plants could recover from the oxidative damages to a certain extent in the recuperation phase (31–60 days). C. indica exhibited relatively lesser ROS accumulation and oxidative damage during the experimental phase than other selected plants. The study also showed that plant biomass, transpiration rate, chlorophyll content, root exudates, and root activity influenced the removal of CBZ by various plants (r – 0.76 to 0.98, P < 0.05). The mass balance analysis indicated that a significant proportion of CBZ (49.2 to 72.7 %) underwent metabolism in the plant tissues. Apart from higher removal, lesser accumulation, and lower oxidation stress, multi-criteria decision analysis showed that C. indica is a potential plant species for the removal of CBZ.
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•Studied fate of carbamazepine and its effect on antioxidant activity of plants.•Exposure to carbamazepine increased the oxidative stress in selected plant species.•Biomass, transpiration, chlorophyll, root activity, and exudates govern CBZ removal.•Plants could recover from the oxidative stress in the recuperation phase.•Canna indica showed higher removal, lesser oxidation stress, and faster recovery.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•The substrates made of kermesite and zeolite achieve an unsatisfactory TP reduction.•The best reduction results among the analysed heavy metals were obtained for Cu.•The lowest effectiveness of TKN ...reduction was observed in CW with bark.
Constructed wetlands (CW) with vertical flow were used to treat leachate from municipal landfills (active and closed, at different concentrations) using a combination of substrates, i.e., gravel, sand and an exchangeable layer, depending on a variant: organic substrate (pine bark) or mineral substrate (zeolite, expanded clay). The systems were planted with Phragmites australis. The aim of this study was to compare the efficiency of removal of selected pollutants from landfill leachate in CW using different types of filling. For most parameters, the best reductions were obtained on zeolite substrates. In the investigated CW, reductions were achieved at the levels of: AN 96%-99%; TKN 75%-88.5%; TN 62.5%-70%, TP 84–88% and heavy metals (Zn, Ni, Cu, Cr) 41%-56%.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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•The Fe plaque content decreases significantly with the elevation of the tidal flat.•The content of Fe plaque in roots of Phragmites is higher than that of Spartina.•High soil Eh is ...conducive to the formation of crystalline Fe plaque.•The diversity of rhizosphere bacteria in Phragmites is higher than that in Spartina.•The rhizosphere of Phragmites at low tide flat enriches more Fe bacteria than Spartina.
As two common estuarine wetland plants in China, Spartina alterniflora and Phragmites australis significantly differ in the mechanism of gas transportation and radial oxygen loss, and this difference can lead to significant differences in the shaping of the rhizosphere bacterial community and the formation of root iron (Fe) plaque. In this study, the difference in root Fe plaque formation between S. alterniflora and P. australis on the redoxcline of tidal flat was determined, and the composition of Fe-oxidizing bacteria (IOB) and Fe-reducing bacteria (IRB) communities in the rhizosphere and Fe plaque of the two plants was compared. With the increase in soil redox potential (Eh), the Fe plaque (amorphous and crystalline forms) content in the roots of S. alterniflora and P. australis decreased significantly. The Fe plaque content in the roots of P. australis was significantly higher than that of S. alterniflora, regardless of the tidal level. High soil Eh improved the formation of crystallized Fe plaque, as the proportion of crystalline Fe plaque increased significantly with the increase in soil Eh. Under similar soil Eh, the microbial diversity of the P. australis rhizosphere was higher than that of the S. alterniflora rhizosphere. The relative abundances of the dominant IOB and IRB, such as the genera Desulfuromonas, Geothermonbacter, Pseudomonas, Paracoccus, Geobacter, Amaricoccus, Pelobacter, and Gallionella, in the P. australis rhizosphere in low-tidal flat are generally higher than those in the S. alterniflora rhizosphere. However, the relative abundances of primary IRB (such as Desulfuromonas) and IOB (such as Pseudomonas) in the rhizosphere of the two plants increased with the increase in soil Eh and soil total Fe content, indicating that the enrichment of Fe bacteria in the S. alterniflora and P. australis rhizospheres may not be the primary determinant of Fe plaque formation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Methane (CH4) emissions via ebullition contribute significantly to greenhouse gas emissions from freshwater bodies. According to the literature, the ebullition pathway may even be the most important ...pathway in some cases, particularly in shallow lakes. Ebullition rates are not often estimated because of the high uncertainty associated with episodic releases, leading to difficulties in their determination. This study provides an estimate of such emissions in a large, shallow, subsaline lake in eastern Austria, Lake Neusiedl, and compares them to the diffusion pathway. Ebullition gas sampling was conducted every 5–10 days over a period of 107 days from late March to mid-July 2021, using ebullition traps placed in three distinct locations: Reed belt, Channel and Open water/Lake. The aim was to study the temporal and spatial heterogeneity of ebullition and its contribution to total emissions. At the same time, several water quality and other environmental parameters were measured and then tested against the CH4 ebullition rates to explore them as potential drivers for this pathway. The carbon isotope fractionation factor (αC) of the measured CH4 ebullition gas, ranging from 1.03 to 1.06, indicates a dominance of the acetoclastic methanogenesis in the sediments of Lake Neusiedl, regardless of the location. The Reed belt location showed the highest mean CH4 ebullition rate (17 ± 28 mg CH4 m−2 d−1), which is >340-fold higher than the mean of the other two locations, and demonstrated also a strong temperature dependency. In all locations at Lake Neusiedl, the median CH4 fluxes via diffusion are significantly higher than via ebullition. Our analyses do not confirm the dominance of the ebullition pathway in any of the studied locations. Whereas at the Reed belt, ebullition accounts for 48 % of the CH4 emissions, in the other two locations, is responsible only for about 1 %.
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•Higher median CH4 fluxes via diffusion compared to ebullition at Lake Neusiedl.•Acetoclastic methanogenesis is the dominant CH4 production type at Lake Neusiedl.•Highest (mean) CH4 fluxes occur at the Reed belt site, irrespective of the pathway.•In the Reed belt, ebullition contributes 48 % to the total cumulative CH4 emission.•In the Channel and Open water/Lake locations, ebullition accounts for only about 1 %.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
To investigate the impacts of spatial expansion by Phragmites australis on spatiotemporal variations of sulfur (S) fractions in marsh soils of the Min River estuary (Southeast China), the contents of ...total sulfur (TS) and inorganic sulfur (IS) fractions (Water-Soluble-S, W-S-S; Adsorbed-S, A-S; HCl-Soluble-S, H-S-S; and HCl-Volatile-S, H-V-S) were determined in soils of Cyperus malaccensis marsh (before expansion, BE stage), P. australis-C. malaccensis marsh (during expansion, DE stage) and P. australis marsh (after expansion, AE stage) by space-for-time substitution method. Results showed that the expansion of P. australis greatly altered the spatiotemporal variations of TS and IS fractions in marsh soils. The TS contents in soils at AE stage were significantly lower than those at DE and BE stages throughout a year (p < 0.01). Higher levels of W-S-S, A-S, H-S-S and total inorganic sulfur (TIS) generally occurred in soils at DE and AE stages, whereas higher values of H-V-S were observed in soils at BE stage. Although P. australis expansion did not alter the temporal variations of TS stock in soils greatly, the values during autumn and winter were generally higher than those in spring and summer (p < 0.05). The highest TIS stocks in soils of different expansion stages were observed in spring, while the lowest values occurred in summer. The expansion of P. australis significantly increased the IS supply capacity of soils and, compared with the BE stage, stocks of W-S-S, A-S, H-S-S and TIS in soils of all sampling seasons at DE and AE stages increased by 51.40 %, 50.76 %, 63.35 %, 50.52 % and 20.00 %, 31.46 %, 42.93 %, 27.56 %, respectively. It was worth noting that stocks of H-V-S in soils at DE and AE stages showed a decreasing trend compared to the BE stage, implying that the expansion of P. australis might reduce the production of sulfides. This paper found that, compared with C. malaccensis, the increased available IS stocks in soils might be an effective strategy for P. australis to maintain its expansion advantage and the decreased volatile-S in soils might be more favorable for boosting its competitiveness. Our study provided valuable information for understanding the interspecific competition mechanism between P. australis and C. malaccensis. Next step, in order to protect the diversity of marsh vegetations in the Min River estuary, effective measures should be taken to suppress the rapid expansion of P. australis.
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•Expansion of Phragmites australis significantly altered the variations of S fractions in soils.•Expansion of P. australis increased W-S-S, A-S, H-S-S and TIS levels but decreased H-V-S levels.•Variations of S fractions primarily rested with the alterations of soil physiochemical properties.•Expansion of P. australis did not alter the variations of TS stock but increased IS supply capacity.•Increased IS stock was an effective strategy for P. australis to maintain its expansion advantage.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Estuaries along with their saltmarshes are extremely relevant areas to what ecosystems conservation is concerned. Not only do they provide unique conditions to house numerous species but can also ...play an important role in pollution mitigation. This study aimed to evaluate the role of saltmarsh plants in metals retention in the long term, using a previously monitored estuary as a case study (Lima river estuary). Seasonal sampling campaigns were carried out in 2022 to determine the metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) concentrations in vegetated and non-vegetated sediments, as well as in saltmarsh plants at three sites within the estuarine area, Canogem, Salinas and Srª das Areias. Results showed saltmarsh plants, despite some seasonal variability, are concentrating metals in their rhizosediments (ratio metal in vegetated sediment / metal in non-vegetated sediment >1) and in their roots, namely Cd, Cu and Zn (ratio metal in plant roots / metal in non-vegetated sediment >1). This role seems to be maintained in the long term, with plant metal retention levels similar in 2009 and 2022, indicating plants are probably contributing to remove metals from the surface water. However, this feature seems to be decreasing in one of the sites, Srª das Areias, that shows signs of degradation. Thus, saltmarsh plants have the potential to retain metals in estuarine areas, contributing to reduce metals present in the aquatic environment and preventing them from spreading through the estuarine area, from reaching coastal areas and eventually from reaching underlying aquifers. Protection of this environment is mandatory and the promotion of re-vegetation of non-vegetated estuarine areas is needed so that the saltmarsh works as a nature-based solution that prevents and/or recovers impacted environments, in order that saltmarshes can continue to deliver their multiple co-benefits.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The concentrations of heavy metals in the roots, rhizomes, stems and leaves of the aquatic macrophyte
Phragmites australis (common reed), and in the corresponding water and sediment samples from the ...mouth area of the Imera Meridionale River (Sicily, Italy), were investigated to ascertain whether plant organs are characterized by differential accumulation, and to test the suitability of the various organs for heavy metal biomonitoring of water and soil. Heavy metals considered were Cd, Cr, Cu, Hg, Mn, Ni, Pb, Zn. Results showed that belowground organs were the primary areas of metal accumulation. In particular, metal concentrations in plant organs decreased in the order of root
>
rhizome
≥
leaf
>
stem. All four organs showed significant differences in concentration for Cr, Hg, Mn, Zn, thus suggesting low mobility from roots to rhizomes and to aboveground organs. Although the organs followed different decreasing trends of metal concentration, the trend Mn
>
Zn
>
Pb
>
Cu was found in each plant organ. Mn showed the highest concentrations in all organs whereas the lowest concentrations regarded Cd and Cr in the belowground and aboveground organs, respectively. The toxic threshold was exceeded by Cr in roots, rhizomes and leaves, Mn in roots and leaves, Ni in roots. The highest average concentrations were found as follows: Cd, Hg, Pb, Zn in root, Cr, Mn, Ni in sediment, Cu in water. Positive linear relationships were found between heavy metal concentrations in all plant organs and those in water and sediment, thus indicating the potential use of such organs for pollution monitoring of water and sediment. Advantages of using plant species as biomonitors, especially
Phragmites australis, were also discussed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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