Phragmites Australis Research Articles

Seismic performance of compressed earth block walls reinforced with common reeds

Compressed earth block (CEB) is a sustainable and cost-effective option for eco-friendly constructions. The blocks are produced without burning fossil fuels and have low embodied energy. The abundance of its constituents, including clay and sand, is another merit. However, the susceptibility of CEB constructions against seismic forces is still considered a prominent hindrance to their widespread acceptance. The study aims to improve the in-plane seismic performance of CEB walls by using common reeds as a natural reinforcing material. For this purpose, seven wall panels with dimensions of 1000×900×120 mm3 were constructed. Seismic loading was simulated using an incrementally increasing lateral cyclic displacement combined with a constant vertical stress of 0.3MPa. The results are discussed in terms of the hysteresis load-displacement responses, displacement ductility, energy dissipation, and stiffness degradation. Based on laboratory experiments, the strength and lateral displacement of the reinforced specimen with four vertical reeds were increased by 44% and 76%, respectively, compared to the non-reinforced ones. Ultimately, Seismic assessments and damage indexes of the tested walls indicated that the in-plane seismic performance of CEB walls could be significantly improved by using vertical sand-coated reeds.

Ecological analysis and multi-scenario simulation of Yellow River Delta wetland under clearing of Spartina alterniflora

In 2022, China released the Special Action Plan for the Control of Spartina alterniflora (2022-2025) with the goal of completely clearing S. alterniflora from China's coastal wetlands. It is crucial to conduct a thorough analysis of wetlands under artificial intervention and obtain reliable future wetland simulation results. The Yellow River Delta wetland is one of China's important wetland reserves, has faced severe impacts from S. alterniflora invasion over the past decade. This study focuses on the Yellow River Delta wetland, utilizing Landsat imagery and a combined object-oriented and pixel-based approach to achieve wetland mapping from 2013 to 2023. Through wetland analysis, we designed scenarios for natural development, ecological priority, farmland protection, and combined development. The patch generating land use simulation model was used to simulate wetland scenarios for 2030 and analyze factors influencing wetland use cover change and future conversion patterns. The results indicate that between 2013 and 2022, native vegetation was impacted by the invasion of S. alterniflora, with Suaeda glauca being the most affected. In 2023, the removal of S. alterniflora was effective, reducing its area by 42.37km2 compared to pre-removal conditions. In all three scenarios, the area of Phragmites australis increased and is expected to dominate the wetlands, while the live space of other native salt marsh vegetation has also been restored. However, the predictions indicate that S. alterniflora still poses a potential threat of expansion in the future, necessitating continuous monitoring of its dynamics. We recommend implementing zoned management of the wetland, balancing ecological restoration in coastal areas with agricultural development in the western regions.

Source and degradation of soil organic matter in different vegetations along a salinity gradient in the Yellow River Delta wetland

Salt marsh wetlands exhibit high carbon capture and storage capabilities, which are crucial for mitigating climate change. However, the mechanisms of soil organic carbon (SOC) sequestration in coastal deltaic salt marsh wetlands are not well understood. To bridge this gap, we present new findings on the distribution, sources, and decomposition of SOC in the Yellow River Delta wetland, focusing on four vegetation types along a salinity gradient: Phragmites australis, Tamarix chinensis, Suaeda salsa, and Spartina alterniflora. The input of litter was found to be the primary factor affecting SOC at the depth from 20 to 100 cm, while microbial degradation and clay content were the main factors in the deeper soil layers between 20 and 100 cm. The SOC in all four communities was predominantly derived from recalcitrant organic carbon (81 %–99 %). A Monte Carlo model revealed that terrestrial sources accounted for 61 % of SOC, plant sources for 31 %, and marine sources for 8 %. The vertical distribution of δ13C profiles in Phragmites australis and Spartina alterniflora communities was influenced by preferential utilization of 12C and substrate, with SOC degradation rate constants of 0.28 and 1.02 per annum (a−1), respectively. The invasion of Spartina alterniflora has led to a significant increase in the easily oxidizable carbon (EOC) to SOC ratio, thus reducing SOC stability, which underscores the importance of mitigating Spartina alterniflora invasion. SOC stability was increased by evaluated salinity in the Yellow River Delta wetland, which was higher than that in Chinese coastal wetlands.

Metal(loid) tolerance, accumulation, and phytoremediation potential of wetland macrophytes for multi-metal(loid)s polluted water.

Natural based solutions, notably constructed/artificial wetland treatment systems, rely heavily on identification and use of macrophytes with the ability to tolerate multiple contaminants and grow for an extended period to reduce contamination. The potential to tolerate and remediate metal(loid) contaminated groundwater from an industrial site located in Flanders (Belgium) was assessed for 10 wetland macrophytes (including Carex riparia Curtis, Cyperus longus Baker, Cyperus rotundus L., Iris pseudacorus L., Juncus effusus L., Lythrum salicaria L., Mentha aquatica L., Phragmites australis Trin. ex Steud., Scirpus holoschoenus L., and Typha angustifolia L.). The experiment was conducted under static conditions, where plants were exposed to polluted acidic (pH ~ 4) water, having high level of metal(loid)s for 15days. Plant biomass, morphology, and metal uptake by roots and shoots were analysed every 5days for all species. Typha angustifolia and Scirpus holoschoenus produced ~ 3 and ~ 1.1 times more dried biomass than the controls, respectively. For S. holoschoenus, P. australis, and T. angustifolia, no apparent morphological stress symptoms were observed, and plant heights were similar between control and plants exposed to polluted groundwater. Higher concentrations of all metal(loid)s were detected in the roots indicating a potential for phytostabilization of metal(loid)s below the water column. For J. effusus and T. angustifolia, Cd, Ni, and Zn accumulation was observed higher in the shoots. S. holoschoenus, P. australis, and T. angustifolia are proposed for restoration and phytostabilization strategies in natural and/or constructed wetland and aquatic ecosystems affected by metal(loid) inputs.

Community Assembly Mechanisms of Populus euphratica in Northwest China and Their Relationship with Environmental Factors

Populus euphratica is a key community-building species in the desert riparian forests of Northwest China, exhibiting exceptional resistance to stress and playing a vital role in soil and water conservation as well as maintaining ecological balance in arid regions. To investigate the ecological processes underlying the composition of P. euphratica communities and to identify their community construction mechanisms, this study analyses the species diversity and phylogenetic diversity of 58 P. euphratica communities, exploring their assembly processes and key influencing factors. This research aims to elucidate the relationship between community structure from the perspective of species evolution and analyse the construction mechanisms of P. euphratica communities across different clusters in arid environments. The results show that the species diversity of P. euphratica clusters in Northwest China is relatively low, and a significant correlation is noted with phylogenetic diversity (PD). The Shannon–Wiener and Margalef indices exhibit similar trends, whereas Simpson’s index show the opposite trends. Pielou’s index range from 0.7 to 0.85. Notably, the PD and species diversity of the P. euphratica–Haloxylon ammodendron association group (Group 4) is significantly higher (p < 0.05) compared to that of the other groups. Additionally, net relatedness index (NRI) and nearest taxon index (NTI) peaked in the P. euphratica–H. ammodendron association group (Group 4) and the Populus pruinosa–Tamarix ramosissima–Phragmites australis association group (Group 1) (p < 0.05). A Pearson correlation analysis indicated that PD was significantly positively correlated with Margalef’s index, Shannon–Wiener’s index, and Pielou’s index, but was significantly negatively correlated with Simpson’s index, while also being associated with environmental factors. Key factors influencing the diversity of P. euphratica communities in Northwest China include total phosphorus, pH, soil moisture content, total potassium, the mean temperature of the coldest quarter, precipitation of the wettest month, and precipitation seasonality. Soil factors primarily affected the Pielou and Simpson indices of species diversity, whereas climatic factors mainly influenced the Margalef and Shannon–Wiener indices. PD and structure were mainly influenced by climatic factors. The combined effects of soil and climatic factors play a crucial role in sustaining the diversity and ecological adaptation of these plant communities. In summary, P. euphratica communities may exhibit a significant ecological niche conservation in response to environmental changes, and competitive exclusion might be the primary process shaping community structure. Climatic factors were shown to be important regulators of community diversity and phylogenetic structure.

Olive mill wastewater treatment using vertical flow constructed wetlands (VFCWs)

The study explores a synergistic two-phase system to treat olive mill wastewater (OMW), comprising a multilayer adsorbent filter (pretreatment) and a vertical flow constructed wetland (VFCW). The pretreatment phase includes layers of commercial granular activated carbon (CGAC) and volcanic tuff (VT), while the VFCW phase consists of planted tank with Phragmites australis reeds and unplanted tanks. Initially, municipal wastewater is introduced into the VFCW to establish the required microbial community. Then, pre-treated OMW is passed through the VFCW. The removal rates of various pollutants were assessed. The planted VFCW showed superior removal efficiencies, averaging 97.82% for total chemical oxygen demand (CODT), 92.78% for dissolved oxygen demand (CODd), 99.61% for total phenolic compounds (TPC), 98.94% for total nitrogen (TN), 96.96% for ammonium, and 95.83% for nitrate. In contrast, the unplanted VFCW displayed lower removal efficiencies, averaging 91.47% for CODT, 77.82% for CODd, 98.53% for TPC, 97.51% for TN, 92.04% for ammonium, and 90.82% for nitrate. These findings highlight the significant potential of VFCWs, which offer an integrated approach to OMW treatment by incorporating physical, chemical, and biological mechanisms within a single treatment system.Graphical

Simulation of wetland vegetation succession based on coupled Gaussian and population dynamics models: A case study of Poyang Lake wetlands

Wetland vegetation is the most crucial primary producer in wetland ecosystems and serves as an indicator of ecosystem health. After 2003, significant changes occurred in the “river-lake relationship” between Poyang Lake and the Yangtze River, with intensified dry conditions in autumn and winter leading to a shortened inundation period for sandbanks and significant changes in the community structure and spatial distribution of wetland vegetation. By coupling a Gaussian model with a population dynamics model, this study simulated the response of wetland vegetation to inundation duration under different hydrological year types, revealing the relationship between vegetation distribution and inundation duration. Key parameters, such as growth and mortality rates, were identified, and the vegetation succession and spatial distribution of Poyang Lake wetlands were simulated for five representative years: a wet year (2010), a normal year (2001), a dry year (2006), an extreme wet year (1998), and an extreme dry year (2022). The results showed that the response of wetland vegetation to inundation duration followed a Gaussian curve, with each species exhibiting an optimal range of inundation durations. Mortality rates increased when the duration fell outside this range. In 2010, the total area of wetland vegetation was similar to that in a normal year, but the proportions of different plant species varied significantly. Compared to 2001, the areas of Phalaris arundinacea and Polygonum criopolitanum increased by 50.92 % and 24.86 %, respectively, while the areas of Phragmites australis and Triarrhena lutarioriparia decreased by 71.66 % and 83.49 %. In 1998, the total vegetation area shrank considerably, with a 54.74 % reduction compared to 2001 and a 64.32 % reduction compared to 2006. In contrast, the total wetland vegetation area reached its maximum in the extreme dry year of 2022, increasing by 41.35 % compared to 2001. Among dominant species, Carex spp., Cynodon dactylon, and Phragmites australis expanded significantly in dry years, while Phalaris arundinacea and Polygonum criopolitanum were better adapted to flood conditions.

Effects of environmental and biological characteristics on leaf decomposition under wetland restoration conditions

The implementation of ecological restoration projects, such as wetland rehabilitation, is essential for achieving sustainable development. However, current research on monitoring recovery status primarily focuses on evaluating water quality and aquatic community structure, with limited understanding of macroinvertebrate and microbial networks, as well as the functions of restored ecosystems. To address this gap, we compared the leaf decomposition rates of reed (Phragmites australis) and sedge (Carex appendiculata) in short-term (1, 2, and 3 years) and long-term (17 years) restoration wetlands, using natural wetlands as controls to assess ecosystem function. Our results indicate that the leaf decomposition rate in restored wetlands is significantly lower than in natural wetlands. No significant difference in decomposition rates was detected between the two types of leaves (P>0.05). All evaluation categories, including biological network structure, influenced leaf decomposition in different wetlands, with distinct effects observed on reed and sedge leaves. Compared to sedges, the decomposition of reed leaves exhibited a stronger correlation with macroinvertebrates while showing a weaker association with microorganisms and co-occurring network topological parameters. Overall, the execution of wetland restoration projects positively influences the recovery of biodiversity co-occurrence networks and ecosystem functions. These findings provide valuable insights for environmental and sustainability assessments.

Using phragmites australis biochar bio-augmented with actinomycetes for enhancing UASB reactor performance: A field study

Anaerobic processes are a cost-effective and sustainable method for wastewater treatment due to their lower energy demand and potential for biogas-high methane recovery. The up-flow anaerobic sludge blanket reactor system (UASB) is a commonly used technology. This study aimed to evaluate the performance of UASB reactors for handling the wash water from the buffalo shed, with a comparison of traditional UASB to UASB modified reactor by incorporation of immobilized biochar with and without bioaugmentation of a bacterial species with documented anaerobic capabilities. The investigation was conducted as a pilot project at the Suez Canal University Veterinary Experimental Farm in Ismailia, Egypt. Adding Streptomyces hydrogenans S11-immobilized Phragmites australis biochar to the USAB reactor increased removal efficiency, even at high influent loadings. The findings demonstrated that the traditional UASB reactor attained removal efficiency for COD, BOD5, TSS, TDS, color, and turbidity of 81.0 %, 75.0 %,80.0 %, 80.0 %, 70.0 %, and 70.0 % respectively, and biogas production of (0.025 mL biogas/mg COD removed).In comparison, the modified UASB reactor attained COD, BOD5, TSS, TDS, Color, and Turbidity removal efficiencies of 93.0 %, 91.5 %,90.3 %, 91.10 %, 85 %, and 80.0 %, respectively. The biogas production reached (0.037 mL biogas/mg COD removed). The removal efficiencies of the measured parameters were statistically analyzed, and this analysis indicated that the efficiency of the modified reactor was enhanced dramatically compared to the traditional system. Hence, this work demonstrates an efficient approach for treating buffalo wastewater.

The Bioaccumulation of Potentially Toxic Elements in the Organs of Phragmites australis and Their Application as Indicators of Pollution (Bug River, Poland)

The bioaccumulation of potentially toxic elements (PTEs) in aquatic plants is critical in assessing the quality of aquatic environments and the risks associated with anthropogenic activities. This research involved using Phragmites australis as a bioindicator in a comprehensive assessment of the spatial variation in pollution within the Bug River catchment, employing advanced statistical methods to identify pollution sources. The study aimed to investigate the bioaccumulation of PTEs in different parts of the P. australis plant and to evaluate their suitability as bioindicators of contamination. Plant samples were collected from 32 locations in the Bug River catchment, and the concentrations of metals such as Cd, Pb, Cr, Ni, Zn, Cu, Fe, and Mn were determined by atomic absorption spectrometry. The results indicated that PTE accumulation was highest in the roots, underscoring their crucial role in monitoring metal concentrations. Metal concentrations differed based on land use within the catchment area, with the highest levels observed in urbanized regions, highlighting the significant impact of human activities like wastewater discharge and transport emissions. The highest concentrations were observed for Fe, Mn, and Zn, while Cd concentrations were notably elevated in agricultural areas. The analyses confirmed that P. australis serves as an effective bioindicator of heavy metal contamination and can be employed in long-term biomonitoring programs.

Combined effect of temporal inundation and aboveground-cutting on the growth performance of two emergent wetland plants, Phragmites australis and Bolboschoenus planiculmis.

Phragmites australis is a common foundation species found in inland and brackish estuarine ecosystems. P. australis stands provide a wide range of habitats for wetland organisms and perform essential functions, such as nutrient cycling, pollutant filtration, wave energy reduction, and soil stabilization. However, excessive growth of P. australis can degrade the quality of wetland habitats, thereby reducing the functions of restored wetlands. In this study, we investigated the effectiveness of vegetation management techniques, such as aboveground cutting and temporal inundation with varying depth and periodicity, in controlling the growth performance of P. australis and adjacent vegetation, Bolboschoenus planiculmis. Differences in growth responses to manipulated inundation stress between P. australis and B. planiculmis were measured. Inundation stress of 10-50 cm caused significantly greater inhibition of growth performance in B. planiculmis compared to P. australis. The combination of aboveground-cutting and inundation treatments resulted in a significant inhibitory effect on the growth performance and survival rate of P. australis. The growth performance of P. australis, including stem volume and biomass, decreased and its mortality rate increased. Our manipulated experiment suggests a combined treatment approach of moderate inundation, such as 5-10 cm for 20-30 days, and aboveground cutting to manage the overgrowth of P. australis in restored brackish wetlands.

The Effects of Anthropogenic Stressors on Above- and Belowground Phytochemical Diversity of the Wetland Grass, Phragmites australis.

Coastal wetlands face threats from climate change-induced flooding and biological invasions. Plants respond to these stressors through changes in their phytochemical metabolome, but it is unclear whether stressors affecting one tissue compartment (e.g., leaves) create vulnerabilities in others (e.g., roots) or elicit similar responses across tissues. Additionally, responses to multiple simultaneous stressors remain poorly understood due to the focus on individual metabolites in past studies. This study aims to elucidate how the phytochemical metabolome of three Phragmites australis (Cav.) lineages, common in the Mississippi River Delta, responds to flooding and infestation by the non-native scale insect Nipponaclerda biwakoensis (Kuwana). Among these lineages, one is non-native and poses a threat to North American wetlands. Results indicate that metabolomic responses are highly specific, varying with lineage, tissue type, stressor type, and the presence of multiple stressors. Notably, the non-native lineage displayed high chemical evenness, while the other two showed stressor-dependent responses. The 10 most informative features identified by a machine learning model showed less than 1% overlap with known metabolites linked to water and herbivory stress, underscoring gaps in our understanding of plant responses to environmental stressors. Our metabolomic approach offers a valuable tool for identifying candidate plant genotypes for wetland restoration.

Diversity Patterns and Drivers of Soil Bacterial and Fungal Communities in a Muddy Coastal Wetland of China.

Elucidating the dynamics of soil microbial diversity in coastal wetlands is essential for understanding the changes in ecological functions within these ecosystems, particularly in the context of climate change and improper management practices. In this study, the diversity patterns and influencing factors of soil bacterial and fungal communities in a muddy coastal wetland in China were investigated using Illumina sequencing of 16S rRNA and ITS1, across wetlands dominated by different vegetations and varying proximity to the coastline. The wetlands include four plots dominated by Spartina alterniflora (SA1), four plots dominated by Suaeda glauca (SG2), additional four plots of Suaeda glauca (SG3), and four plots dominated by Phragmites australis (PA4), ranging from the nearest to the coast to those farther away. The results revealed significant differences in bacterial richness (Observed_species index) and fungal diversity (Shannon index) across different wetlands, with SG3 demonstrating the lowest bacterial Observed_species value (1430.05), while SA1 exhibited the highest fungal Shannon value (5.55) and PA4 showing the lowest fungal Shannon value (3.10). Soil bacterial and fungal community structures differed significantly across different wetlands. The contents of soil available phosphorus and total phosphorus were the main drivers for fungal Observed_species and Shannon index, respectively. Soil organic carbon, pH, and salinity were indicated as the best predictors of bacterial community structure, accounting for 28.1% of the total variation. The total nitrogen content and soil salinity contributed mostly to regulating fungal community structure across different wetlands, accounting for 19.4% of the total variation. The results of this study offer a thorough understanding of the response and variability in soil microbial diversity across the muddy coastal wetlands in China.

Iron-bound organic carbon declined after estuarine wetland reclamation into paddy fields

Iron-bound organic carbon (Fe-OC) is a main pathway for the long-term maintenance of soil organic carbon (SOC), but research on its mechanism is still relatively weak. We investigated the coupling relationships among iron (Fe), carbon (C) and Fe-reducing bacteria (FeRB) in the soil of a reclaimed paddy field in comparison with natural Phragmites australis wetland in the Minjiang River estuary in southeastern China. The results showed that conversion of P. australis wetland to paddy cultivation changed the soil redox process. After reclamation, soil Fe(II), Fe(III), HCl-Fet, free iron oxide (Fed) and amorphous iron (Feo) contents and Fe(III)/Fe(II) decreased significantly (p < 0.05), while the content of complexed iron (Fep) increased. Nonmetric multidimensional scaling analysis (NMDS) demonstrated variability in FeRB across soil types (r = 0.900, p = 0.001). The lower Fe-OC concentration in soil after wetland reclamation may be the result of Fe reduction by dissimilatory FeRB (e.g., Bacillus, Anaeromyxobacter). On average, both Fe-OC and SOC contents decreased significantly (p < 0.05), while the contribution of Fe-OC to total SOC (fFe-OC) increased significantly (p < 0.05), after conversion to paddy cultivation. Structural equation modeling (SEM) showed that SOC, dissolved organic C, and Fe-OC were affected by FeRB and the speciation of Fe. In addition, Fe (III) concentration affected SOC concentration (r = 0.60, p < 0.05) and DOC concentration (r = 0.58, p < 0.05), and Fed affected DOC concentration (r = 0.69, p < 0.05). We conclude that after rice field reclamation in estuarine wetlands, Fe-reducing bacteria can mediate iron-bonded organic C decoupling, affecting SOC stabilization.

Numerical Approximation Tool Prediction on Potential Broad Application of Subsurface Vertical Flow Constructed Wetland (SSVF CW) Using Chromium and Arsenic Removal Efficiency Study on Pilot Scale

\noindent {\bf Abstract:} This study investigates the potential broad application of Subsurface Vertical Flow Constructed Wetlands (SSVF CWs) for heavy metal remediation, focusing on Chromium (Cr) and Arsenic (As) removal efficiency. A pilot-scale experimental setup was employed, utilizing a SSVF CW filled with 12 mm gravel and 2 mm coarse sand, planted with Phragmites Australis. The research, conducted over 366 days, aimed to develop a numerical approximation tool to predict the performance and applicability of SSVF CWs in various environmental conditions. The experimental system operated at a hydraulic loading rate of $98-111 \mathrm{~mm} / \mathrm{d}$ and a hydraulic retention time of 6 days. Results showed average removal efficiencies of $44.87 \pm 9.52 \%$ for Cr and $43.16 \pm 9.43 \%$ for As. A mass balance analysis revealed that substrate accumulation was the primary mechanism for heavy metal removal, accounting for $29 \%$ of Cr and $26 \%$ of As removal. Plant uptake contributed to $3.5-9.9 \%$ of Cr and $0.3-$ $8.8 \%$ of As removal. Based on these findings, a numerical model was developed to simulate SSVF CW performance under varying environmental and operational parameters. The model incorporated factors such as influent concentrations, hydraulic loading rates, substrate composition, and plant species. Validation against experimental data showed good agreement, with an $\mathrm{R}^{2}$ value of 0.89 . The numerical tool was then used to predict SSVF CW performance across a range of scenarios, indicating potential broad applications in industrial wastewater treatment, mine drainage remediation, and contaminated groundwater cleanup. This study provides valuable insights into the scalability and versatility of SSVF CWs for heavy metal removal, offering a sustainable and cost-effective solution for water treatment challenges.\\

Quantitatively unveiling the role of coastal wetlands in regulating eutrophication and enhancing water environmental capacity

Human activities have intensified the global challenge of coastal eutrophication. Recently, water resource managers have encountered difficulties in formulating precise pollutant reduction strategies to mitigate coastal eutrophication. Despite the recognized importance of coastal wetlands and pollution sources in influencing coastal nutrient levels, accurately quantifying their impact remains difficult. To address this challenge, this study introduces a novel approach for optimizing water environmental capacity. A coupled model integrating hydrodynamics, water quality, and wetland nutrient mechanisms was developed to simulate the spatio-seasonal distribution of water, sediment, and vegetation nutrients in a semi-enclosed bay (Liaodong Bay, China) and a large-scale coastal wetland (Liaohe estuary wetland, China). Model parameters and simulation results were calibrated and validated using extensive long-term field investigations and laboratory experiments. The average root mean square errors between simulated and observed values for all validation points were as follows: 0.80mgL-1, 0.53mgL-1, 0.08mgL-1, 6.70μgL-1, and 0.50μgL-1 for dissolved oxygen, chemical oxygen demand, dissolved inorganic nitrogen, dissolved inorganic phosphorus, and chlorophyll-a, respectively. The total nitrogen (TN) and total phosphorus (TP) in the sediment were 0.10gkg-1 and 0.05gkg-1, respectively. For Suaeda salsa, the TN and TP were 2.91gkg -1 and 0.08gkg -1, respectively. For Phragmites australis, the TN and TP were 114.22gkg -1 and 6.21gkg -1, respectively. The results suggest that excessive river discharge and a stable residual circulation structure contribute to the persistent eutrophication in Liaodong Bay. The Liaohe estuary wetland enhances the environmental capacity of dissolved inorganic nitrogen and dissolved inorganic phosphorus in Liaodong Bay to 271±31tyr-1 and 8±1tyr-1, respectively, accounting for 1.8±0.2% and 1.3±0.2% of their respective environmental capacities. The reduction in dissolved inorganic nitrogen concentration is significant, with a maximum decrease of 0.17mgL-1. The maximum contributions of atmospheric deposition and aquaculture wastewater to dissolved inorganic nitrogen concentration are 0.08mgL-1 and 0.03mgL-1, respectively, with higher contributions in spring and summer than in fall and winter. These findings highlight the critical role of coastal wetlands in mitigating eutrophication and underscore the need for spatio-seasonal water management programs. This work serves as a model for effectively reducing global coastal pollution emissions.

GC-MS Analysis and Quantification of Some Secondary Metabolites of the Algerian Phragmites australis Leaf Extract and Their Biological Activities

GC-MS Analysis and Quantification of Some Secondary Metabolites of the Algerian Phragmites australis Leaf Extract and Their Biological Activities

Changing dominance of invasive Phragmites australis and native plant colonization with variation in management, wildfires, and soils in a desert wetland

Abstract Among the most widely distributed species globally, common reed (Phragmites australis (Cav.) Trin. ex Steud.) has generated extensive interest in invasive plant science and management because its introduced strains are highly invasive and often form monocultures that alter ecosystem properties. In desert wetlands in Las Vegas, Nevada, USA, where management goals included reducing hazardous P. australis fuels and increasing native plant diversity, we assessed variation in P. australis cover, the degree of native plant colonization, and soil seed banks after P. australis management treatments (cutting, glyphosate-imazapyr herbicide) and wildfires across gradients in soil properties. Based on change in P. australis cover during six measurement events over 24 months, 24 study sites formed three groups: 1) decreasing cover, where initially high P. australis cover (60-85%) decreased to &lt; 5% following multiple cutting or herbicide treatments; 2) sustaining low cover, where wildfire or clearing was associated with initially low P. australis cover which remained low (&lt; 30%) after multiple herbicide applications; and 3) sustaining high cover (45-100% initially and remaining 30-100%), including sites unmanaged or treated/burned only once. High soil salinity correlated with low post-management P. australis cover. No native plants were detected in the sustaining high P. australis cover group, despite natives occurring in the seed bank. Where management reduced P. australis cover, minimal native plant colonization did occur. Secondary invasion by other non-native plants was nearly absent. Our results suggest that if P. australis can be initially cleared, multiple herbicide applications can persistently keep cover low, especially on drier, saline soils. Slow native plant colonization suggests that a phased approach may be useful to initially reduce P. australis cover, keep it low via repeated treatments, and actively revegetate sites with native species tailored to the moisture-salinity gradient across P. australis-invaded habitats.

Assessment of Metal Pollution in Sediments and Their Bioaccumulation in Phragmites australis from Shoor River, Iran

ABSTRACT Heavy metal contamination is a serious global issue that threatens both environmental and human health. This study investigated the levels of 12 heavy metals in sediments, roots, stems, and leaves of Phragmites australis (common reed) from a river in Iran, using an inductively coupled plasma optical emission spectrometer (ICP-OES). The sediment metal concentration order was: Aluminum (Al) > Iron (Fe) > Manganese (Mn) > Zinc (Zn) > Magnesium (Mg) > Nickel (Ni) > Chromium (Cr) > Lead (Pb) > Copper (Cu) > Arsenic (As) > Vanadium (V) with Cadmium (Cd) below detection limit. Concentrations of As, Ni, Pb, and Zn in the sediments exceeded background values. According to sediment quality guidelines (SQGs), metal concentrations were between the threshold effect level (TEL) and the probable effect level (PEL), remaining below the severe effect level (SEL), except for Ni. Average metal concentrations in plant tissues were lower than in sediment samples, with roots showing higher levels of Cd, V, Cu, Pb, Zn, As, Al, Mg, and Fe than in the shoots, while leaves had higher Ni, Cr, and Mn. The bioaccumulation factor of less than 1 (except for V) indicates limited bioavailibility of these metals.

Assessment of Water Status, Bottom Sediments, Macrophytes in the Light of Index Analysis and Geochemical Parameters of Selected Dam Reservoirs of Kielce Upland (Poland)

Concentrations of trace elements such as Cr, Zn, Cd, Co, Mn, Cu, Ni, Pb, and Fe were investigated in water, bottom sediments, and macrophytes (Phragmites australis and Typha latifolia L.) collected from the Borków, Wilków, and Rejów water reservoirs in the Kielce Upland (Poland). The main objective of this study was to investigate the condition of water, bottom sediments, and macrophytes in selected three sedimentary basins of the Kielce Upland and to identify natural and anthropogenic factors influencing this condition. The secondary objectives were (i) to determine the contents of trace metals in water, bottom sediments, and macrophytes, (ii) to assess the quality of abiotic and biotic elements of the ecosystem based on selected criteria, (iii) to compare reservoirs in terms of pollution, and (iv) to determine the ability of macrophytes to be used as a bioindicator of water/sediment pollution. Field tests were conducted in 2021. The trace metals in water were determined by ETAAS (Cr, Cd, Mn, Cu, Ni, Pb) and FAAS (Zn), and spectrophotometry method (Fe). The trace metals in sediments and macrophytes, including Cr, Zn, Cd, Co, Mn, Cu, Ni, Pb, and Fe, were detected using ICP-OES method. Contamination of bottom sediments with potentially toxic metals was determined based on the geo-accumulation index (Igeo), contamination factor (CF), and pollutant load index (PLI). Statistical analyses were performed using the Statistica PL 13.1. The analyses showed that the accumulation of trace elements in the surface layer of the reservoir sediments increases as follows: in Borków, Cd &lt; Co &lt; Ni &lt; Cu &lt; Pb &lt; Cr &lt; Zn &lt; Mn &lt; Fe; in Wilków, Cd &lt; Co &lt; Cu &lt; Ni &lt; Pb &lt; Cr &lt; Zn &lt; Mn &lt; Fe; and in Rejow, Cd &lt; Co = Cu = Ni = Pb &lt; Zn &lt; Cr &lt; Mn &lt; Fe. It was shown that the average distribution of metals in the bottom sediments of the studied reservoirs was as follows: Borków &gt; Wilków &gt; Rejów. Research has shown that the degree of trace metal accumulation increases as follows: water &lt; sediments &lt; macrophytes (except Pb from the reservoir in Borków).