Macrophyte Species Research Articles

Multidimensional trait variability in a widespread, Paleoarctic macrophyte: functional, spectral and genetic drivers

Understanding how environmental conditions and plant functional variation are mutually related is critical to improving our comprehension of plant adaptations. In this context, our knowledge of the interlinks between plant functional, spectral and genetic traits and environmental filters is still very limited, especially for wetland species. To gain new insights on this topic, a multidimensional dataset, centred on the widespread macrophyte species Nuphar lutea, was assembled by collecting data on functional traits (including spectral traits), genetic metrics and environmental determinants from 28 plots spanning north‐central Italy. A strong environmental filter acts on all traits (morphological, biochemical, spectral and the genetic diversity metrics) resulting in significant local control over trait patterns, exemplified by the discrimination value of water electrical conductivity. This is further reinforced by the key contribution of sediment variables in explaining traits variation. Site‐specific environmental conditions were reflected in different patterns of genetic diversity, suggesting a long‐term effect of environmental filters on genotypes as well. High water conductivity – in our study sites indicative of long‐term hydrogeological settings – is linked to more acquisitive behaviour in N. lutea and a progressive reduction in its genetic diversity, while high nutrients availability in sediments promotes higher leaf traits performance. This study better explores how high variability in leaf traits reinforces current genetic and mechanistic knowledge about competitive strategies in the key aquatic plant N. lutea, by testing the effectiveness of a novel integrative approach to assess multiple sources of plant functional variation.

PEMULIHAN PERAIRAN TERCEMAR MENGGUNAKAN MAKROFITA AIR

Indonesia possesses a potential and diverse biodiversity of plants that can be utilized as phytoremediation agents. One of the ecosystems frequently encountering pollution is the aquatic ecosystem. Therefore, this research is conducted to identify the diversity of aquatic macrophytes with the potential for water remediation efforts. The method employed is qualitative descriptive based on literature review. The literature study revealed 30 species of aquatic macrophytes, with 15 species prominently utilized for environmental remediation. Among these, Ipomea aquatica and Scirpus grossus emerge as the most widely employed aquatic macrophytes.

On aquatic macrophytes in the ultracontinental climate conditions of the Upper Indigirka River

The first results of the study of aquatic macrophytes of the Upper Indigirka River area are presented. The species composition includes ~84 species (~74 vascular plants and more than 10 cryptogamous macrophytes). 47 water bodies of different age, size and origin (tectonic, glacial, river, thermokarst and artificial) were studied. For each type of water bodies, the main ecological characteristics, features of the species composition and vegetation cover are given. The most common type of water bodies of the territory is thermokarst, and the greatest floristic diversity (54 species of macrophytes) is found here. There are 40 species in tectonic lakes, 37 - in rivers lakes, 35 - in glacial lakes, the lowest diversity was for small artificial waterbodies. For the Oimyakon District, new records of protected species are reported: macroalga Tolypella canadensis, vascular plants Isoetes echinospora, Nuphar pumila, Nymphaea tetragona (common and its rare pink-flowered form) and Subularia aquatica. Possible consequences for aquatic ecosystems while maintaining current trends in climate change (increase in average annual temperature, shift to earlier periods of spring warmth, changes in the amount and distribution of precipitation, depth of seasonal thawing of soils) leading to degradation of permafrost and their impact on the biodiversity of aquatic macrophytes in the region are discussed. The most vulnerable aquatic ecosystems of the Oimyakon Highlands are the mature thermokarst lakes.

Species richness pattern of aquatic vascular macrophytes along elevation gradients in Nepal Himalayas

Abstract. Siwakoti EA, Nepali B, Mandal TN, Baniya CB. 2023. Species richness pattern of aquatic vascular macrophytes along elevation gradients in Nepal Himalayas. Biodiversitas 24: 5179-5190. Aquatic vascular macrophytes constitute an important component of aquatic ecosystems. This study aims to determine the species richness pattern of aquatic vascular macrophytes along elevation gradients (100-4900 m asl) in the Nepal Himalayas. We used available published literature on elevational ranges of aquatic vascular macrophytes in Nepal to interpolate the species elevational ranges, thereby providing species richness estimates for 100 m elevational bands. A total of 113 species of aquatic vascular macrophytes belonging to 66 genera under 35 families were recorded from Nepal. Among these macrophytes, dicots were represented by 21 families, monocots with 10 families and pteridophytes with 4 families. Regarding the geographical divisions, the total number of aquatic vascular macrophytes recorded was 76 from the east, 90 from the central and 67 from the west, conclusively central Nepal showed the maximum number of macrophytes. The highest species richness was contributed by Hydrocharitaceae followed by Potamogetonaceae, Plantaginaceae, Lentibulariaceae and Nymphaeaceae. So far, the functional types of macrophytes are concerned, free-floating species were 15, submerged species were 36, floating-leaved species were 18 and emergent species were 44 along elevation gradients in the three geographical divisions in Nepal. The Generalized Linear Model (GLM) was applied to find out the relation between the species richness of aquatic vascular macrophytes with elevation. It showed a statistically significant monotonic declining pattern with increasing elevation. The occurrence of this model was further verified by aquatic vascular macrophyte richness at every 200 m elevation which converged with the general pattern. The study conducted along one of the world’s longest bioclimatic elevational gradients led to support the monotonic declining pattern of aquatic vascular macrophytes richness indicating the difference in richness pattern among aquatic and terrestrial ecosystems. It also emphasizes the importance of conserving aquatic ecosystems with their vegetation.

Epiphytic microorganisms of submerged macrophytes effectively contribute to nitrogen removal

Submerged macrophytes play important roles in nutrient cycling and are widely used in ecological restoration to alleviate eutrophication and improve water quality in lakes. Epiphytic microbial communities on leaves of submerged macrophytes might promote nitrogen cycling, but the mechanisms and quantification of their contributions remain unclear. Here, four types of field zones with different nutrient levels and submerged macrophytes, eutrophic + Vallisneria natans (EV), eutrophic + V. natans + Hydrilla verticillata, mesotrophic + V. natans + H. verticillata, and eutrophic without macrophytes were selected to investigate the microbial communities that involved in nitrification and denitrification. The alpha diversity of bacterial community was higher in the phyllosphere than in the water, and that of H. verticillata was higher compared to V. natans. Bacterial community structures differed significantly between the four zones. The highest relative abundance of dominant bacterioplankton genera involved in nitrification and denitrification was observed in the EV zone. Similarly, the alpha diversity of the epiphytic ammonia-oxidizing archaea and nosZI-type denitrifiers were highest in the EV zone. Consist with the diversity patterns, the potential denitrification rates were higher in the phyllosphere than those in the water. Higher potential denitrification rates in the phyllosphere were also found in H. verticillata than those in V. natans. Anammox was not detected in all samples. Nutrient loads, especially nitrogen concentrations were important factors influencing potential nitrification, denitrification rates, and bacterial communities, especially for the epiphytic nosZI-type taxa. Overall, we observed that the phyllosphere harbors more microbes and promotes higher denitrification rates compared to water, and epiphytic bacterial communities are shaped by nitrogen nutrients and macrophyte species, indicating that epiphytic microorganisms of submerged macrophytes can effectively contribute to the N removal in shallow lakes.

Antimicrobial activity of Pantanal macrophytes against multidrug resistant bacteria shows potential for improving nature-based solutions

The presence of macrophytes in constructed wetlands (CW) applied within the concept of nature-based solution (NBS) is crucial. Besides their role in the phytoremediation of pollutants, the cultivated plants, if properly selected, can also produce a range of bioactive compounds, including those with potential inhibitory effects against pathogenic bacteria. Bioactive compounds, such as flavonoids and ellagitannins, known for their remarkable antimicrobial properties, offer a sustainable solution to the global challenge of antibiotic resistance. In this study, we investigated macrophyte species adapted to the water variations in the Pantanal region (flood and dry seasons), focusing on those with both antimicrobial and ornamental potential, that could improve the ability of a CW system to treat greywater. Seven different macrophyte species were collected, cultivated, and evaluated for their antimicrobial activity (AA) against five standard bacterial strains and five multidrug-resistant clinical bacterial strains. Extracts from the leaf, stem, and root of Polygonum acuminatum showed the best AA against clinical multidrug-resistant strains of Staphylococcus aureus, Enterococcus faecium, and Escherichia coli, with minimum inhibitory concentration (MIC) values ranging from 78.13 to 312.5 µg.mL−1. Furthermore, the leaves of Ludwigia lagunae and P. acuminatum also showed considerable AA against standard strains of Enterococcus faecalis (MIC = 19.5 and 39.06 µg.mL−1, respectively) and Pseudomonas aeruginosa (MIC = 156.25 µg.mL−1 for both). High-Performance Liquid Chromatography with Ultraviolet and Mass Spectrometry analysis of these extracts identified important bioactive compounds, including flavonoids (quercetin 3-rhamnoside, hydropiperoside, quercetin 3-O-rutinoside, quercetin, myricetin 3-O-rhamnoside, kaempferol 3-O-rhamnoside, formononetin, and calycosin) and ellagitannins (3,3′4-tri-O-methylelagic acid, galloys-HHDP-glucose, and ellagic acid), along with other bioactive compounds. These results indicate that P. acuminatum and L. lagunae hold potential for application in CW owing to their antimicrobial property, local adaptability, and ornamental appeal.

Two duckweed species exhibit variable tolerance to microcystin-LR exposure across genotypic lineages

Cyanotoxins produced by harmful cyanobacteria blooms can damage freshwater ecosystems and threaten human health. Floating macrophytes may be used as a means of biocontrol by limiting light and resources available to cyanobacteria. However, genetic variation in macrophyte sensitivity to cyanotoxins could influence their suitability as biocontrol agents. We investigated the influence of such intraspecific variation on the response of two rapidly growing duckweed species, Lemna minor and Spirodela polyrhiza, often used in nutrient and metal bioremediation. We assessed two biomarkers related to productivity (biomass and chlorophyll A production) and two related to fitness measures (population size and growth rate). Fifteen genetic lineages of each species were grown in media containing common cyanotoxin microcystin-LR at ecologically relevant concentrations or control media for a period of twelve days. Genotype identity had a strong impact on all biomarker responses. Microcystin concentration slightly increased the final population sizes of both macrophyte species with a marginal effect on growth rate of L. minor and the chlorophyll A production of S. polyrhiza, but overall these species were very tolerant of microcystin. The strong tolerance supports the potential use of these plants as bioremediators of cyanobacterial blooms. However, differential impact of microcystin exposure discovered in single lineage models among genotypes indicates a potential for cyanotoxins to act as selective forces, necessitating attention to genotype selection for bioremediation.

Distribution and co-occurrence patterns of charophytes and angiosperms in the northern Baltic Sea

The distribution data of 11 soft substrate charophyte and angiosperm species were analyzed. Our study aimed to elucidate the co-occurrence patterns among these sympatric macrophyte species and quantify their distribution areas. The central hypothesis of this study proposed that the observed co-occurrence patterns among the studied species deviate from what would be expected by random chance. Macrophyte occurrence data was derived from an extensive field sampling database. Environmental variables available as georeferenced raster layers including topographical, hydrodynamic, geological, physical, chemical, and biological variables were used as predictor variables in the random forest models to predict the spatial distribution of the species. Permutation tests revealed statistically significant deviations from random co-occurrence patterns. The analysis demonstrated that species tended to co-occur more frequently within their taxonomic groups (i.e., within charophytes and within angiosperms) than between these groups. The most extensive distribution overlap was observed between Chara aspera Willd. and Chara canescens Loisel., while Zostera marina L. exhibited the least overlap with the other species. The mean number of co-occurring species was the highest in Chara baltica (Hartman) Bruzelius while Z. marina had the largest share of single-species occurrences. Based on the distribution models, Stuckenia pectinata (L.) Börner had the largest distribution area.

The role of calcium and alkalinity on phosphorus removal by submerged aquatic vegetation in hardwater wetlands

The Everglades Stormwater Treatment Areas (STAs) are a 25,000 ha (61,000 acre) complex of constructed wetlands built to remove phosphorus (P) from agricultural and urban runoff in support of Everglades restoration. These STAs treat inflow waters that contain P in concentrations from 100 to 200 μg L−1, average calcium (Ca) concentrations of 60–90 mg L−1, and alkalinity (Alk) in the range of 150–350 mg L−1 as calcium carbonate (CaCO3). Photosynthesis, primarily from submerged aquatic vegetation (SAV) within these STAs, increases water pH resulting in CaCO3 formation, which is thought to contribute to P removal through coprecipitation and other processes. Since 2002, the STA complex has removed over 3000 MT of P and over 400,000 MT of Ca. Because the STAs at times treat Lake Okeechobee waters that are lower in Ca and Alk (35–50 mg L−1 and 95–125 mg L−1 as CaCO3, respectively), we conducted two experiments to explore the role of Ca and Alk on wetland P removal.First, in outdoor flow-through microcosms (0.18 m2) containing Najas guadalupensis and treating artificial inflow solutions, Ca/Alk at typical STA inflow concentrations (77 mg Ca L−1/316 mg L−1 as CaCO3) resulted in significantly lower outflow P concentrations compared to lower Ca/Alk treatments (28 mg Ca L−1/67 mg L−1 as CaCO3). Based on sediment organic carbon to total P (TP) ratios, organic matter production and sedimentation was the P removal mechanism under low Ca/Alk levels, where CaCO3 precipitation did not occur, and also under high Ca/Alk, low P (31 μg L−1) conditions, despite CaCO3 formation. High Ca/Alk increased organic matter sedimentation and associated P burial at low and high (168 μg L−1) water P concentrations. Additional P removal associated with CaCO3 precipitation occurred only under high Ca/Alk, high P concentrations, and accounted for about 47% of P sedimentation in those microcosms.Second, in flow-through mesocosms (4.75 m2) containing STA muck soil and common STA SAV species, elevated Ca/Alk (94 mg Ca L−1/185 mg L−1 as CaCO3) produced significantly lower outflow TP concentrations than treatments receiving unamended Lake Okeechobee inflow water with lower Ca/Alk concentrations (44 mg Ca L−1/112 mg L−1 as CaCO3). In the same experiment, Ca/Alk levels had no effect on P removal in mesocosms containing Typha domingensis, a common STA emergent macrophyte species. SAV mesocosms produced lower outflow TP concentrations than Typha, regardless of Ca/Alk levels. In a follow-on laboratory incubation, low Ca/Alk concentrations in incubation waters did not increase P release from sediments formed under prior low or high inflow Ca/Alk concentrations in the SAV mesocosms, but anoxia sharply increased P release from both.These experiments suggest that coprecipitation with CaCO3 is a meaningful P removal process in hardwater wetlands where high P concentrations and SAV coincide. Conversely, in STA outflow regions, where surface water P has already been treated to a low level, coprecipitation with CaCO3 probably does not contribute to further P reductions. However, Ca/Alk also may contribute to inorganic-C availability which influences submerged aquatic productivity, so the role of inorganic C limitation on STA vegetation communities and P removal merits further study.

Aquatic macrophyte growth season in Central and Northern European Union and the implications for aquatic macrophyte risk assessments for herbicides.

Under current European Union regulation, the risks to aquatic organisms must be assessed for uses of plant protection products (PPPs) that may result in exposure to the environment. For herbicidal PPPs, aquatic macrophytes are often the most sensitive taxa. For some herbicidal modes of action, macrophytes may be affected only while they are actively growing. For the risk assessment, it is therefore useful to know whether application timings would result in surface water exposure during periods when aquatic macrophytes are actively growing (therefore potentially resulting in effects). Toxicity endpoints, which are based on studies with active growth, may be overconservative in cases where exposure of PPPs will not co-occur with active macrophyte growth. A comprehensive literature search was performed, using systematic and manual approaches, with the aim of identifying the main active growth period for macrophytes in natural freshwater bodies in climates relevant to the Central and Northern zones of the European Union. The results of the searches were screened initially to identify all potentially relevant references, for which a full evaluation was then performed. Reliability was assessed using the principles of the Klimisch scoring system. As part of the full evaluation, growth periods were identified for each macrophyte species studied. Finally, the extracted growth periods were considered together to determine an overall active growth period for aquatic macrophytes representative of the Central and Northern EU zones. Based on this literature review, the active growth period identified for most aquatic macrophyte species representative of the Central and Northern EU zones is April to September. Relating to the regulatory implication of these results, it may be possible to conclude a low risk for aquatic macrophytes if the predicted surface water exposure period for certain PPPs is demonstrated to be outside the periods of active growth. Integr Environ Assess Manag 2024;20:1125-1139. © 2023 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Observed and estimated taxonomic diversity of different groups of aquatic organisms in the pristine rivers in the Biebrza National Park

The study focuses on the pristine rivers of the Biebrza National Park (BNP), an extensive area of wetlands, which holds significant biodiversity importance on a European scale. The aim of this work was to identify the taxonomic resources of the river network of this area and to compare the biodiversity of various aquatic organisms, and moreover, evaluate the field sampling effort required to identify the whole pool of taxa inhabiting the survey area. Fieldwork was carried out in 2021 at 25 survey sites, where the taxonomic compositions of five groups of organisms were identified: benthic diatoms, phytoplankton, macrophytes, benthic macroinvertebrates, and ichthyofauna and identified taxa have been presented in the appendix. The biodiversity indices of these groups were calculated, i.e. the species richness, and the Shannon and Simpson indices. The entire predicted biodiversity of these groups of organisms was also estimated. The Chao2 asymptotic taxonomic richness estimator for incidence data was used to calculate the additional number of survey sites that would be required to discover 80%, 90% and 100% of the anticipated taxonomic richness in each of the five groups of organisms. With the information on the species inhabiting the Biebrza Valley that this survey yielded, the biodiversity at a single site (alpha diversity) and within the entire area surveyed (gamma diversity) was estimated. The phytoplankton (475 taxa) and the benthic macroinvertebrates (308) showed the greatest diversity in taxonomic richness. In addition, there were 151 species in the benthic diatom group, 72 macrophyte taxa, and 24 fish species. The analysis showed, moreover, that if the fieldwork were continued, another 110 phytoplankton and 104 benthic macroinvertebrates taxa would be recorded for BNP, along with 40 further species of benthic diatoms, 9 more macrophyte species, and 2 more fish species. Alpha diversity was found to be high but gamma diversity was relatively low due to the homogeneous nature of the rivers surveyed (low beta diversity), effective conservation measures, and minimal human disturbances.

Introduce invasive alien macrophytes species in Indonesia national priority lakes (study case: lake Rawa Pening, Sentarum, Tempe, Tondano, Sentani)

According to Presidential Regulation (Perpres) Number 60 of 2021, 15 lakes are classified as Indonesia’s national priority lakes. From 15 lakes, five of them are Tempe (South Sulawesi), Sentarum (West Kalimantan), Rawa Pening (Central Java), Tondano (North Sulawesi) and Sentani (Papua). Aquatic macrophytes are aquatic photosynthetic organisms that can be seen with the naked eye and actively grow periodically or permanently beneath, on, or above the water’s surface. The national priority lakes face upon invasive aquatic macrophytes. Therefore, their presence must be controlled. This research purposed to introduce invasive aquatic macrophytes in several of Indonesia’s national priority lakes. The aquatic macrophytes are recorded using a purposive sampling method with plots square (1x1 m2) and three replications. All aquatic macrophytes were documented, including species, family, population numbers, life forms and origin. The research from these five national priority lakes discovered a total of 10 families and 14 species of invasive aquatic macrophytes. The families were Pontederiaceea, Onagraceae, Polygonaceae, Lentibulariaceae, Araceae, Cyperaceae, Poaceae, Schropulariaceae, Alismataceae, Salviniaceae, and Hydrocharitaceae. The invasive aquatic macrophytes such as Monochoria hastata, Eichhornia crassipes, Persicaria barbata, Ludwigia adscendens, Utricularia aurea, Ludwigia perennis, Pistia stratiotes, Ludwigia peruviana, Cyperus odoratus, Panicum repens, Bacopa floribunda, Limnocharis flava, Salvinia natans, and Hydrilla verticillata. The research result can be used as guidelines for good lakes management.

Seasonal Dynamics of Microphytobenthos Distribution in Three Ecotopes on a Mussel Farm (Black Sea)

As the production of cultured bivalve mollusks is increasing worldwide, there is a growing need to study the biodiversity and ecology of microalgae in the mariculture zones. This study presents multiannual data (obtained in 2015–2016 and 2018–2020) on the species composition, abundance, biomass, and community structure of microphytobenthos from three mussel farm ecotopes (mussel shells, the epiphyton of twenty macroalgal species, and sediments under collectors). In total, 150 microalgal taxa were found, including 135 diatom species with a predominance of benthic (76%), marine (65%), and cosmopolite (30%) ones. In all habitats, 10 potentially harmful species and 44 indicators of organic pollution were noted. The maximum values on the mussel shells (abundance N = 119 × 103 cells/cm2 and biomass B = 0.0489 mg/cm2) were recorded in winter with the dominance of Tabularia fasciculata; in summer, the epiphyton was on the brown alga Nereia filiformis (N = 1001 × 103 cells/cm2 and B = 2.06 mg/cm2) with the dominance of toxic Pseudo-nitzschia seriata, on the red alga Phyllophora crispa (N = 1118 × 103 cells/cm2 and B = 3.24 mg/cm2) with the dominance of T. fasciculata, and in sediments (N = 104 × 103 cells/cm3 and B = 0.046 mg/cm3) with the dominance of T. fasciculata and Bacillaria paxillifer. Statistically significant effects of the ecotope and sampling season on the diatom composition were noted. The strongest effect of temperature is observed for the mussel shell diatoms, for which the trend of abundance and biomass increase in winter and their decrease in summer is most noticeable. But in sediments, the effect of the season is reflected only in the permanent changes of the microalgae species composition. For the epiphyton, it was shown that it is temperature, rather than substrate macrophyte species, that affects its numerical structure.

The similarity assessment of the macrophyte species composition between modern aquatic vegetation and subrecent pollen spectra of small lakes on the Valaam Island (Lake Ladoga)

The similarity assessment of the macrophyte species composition between modern aquatic vegetation and subrecent pollen spectra of small lakes on the Valaam Island (Lake Ladoga)

Optimizing marine macrophyte capacity to locally ameliorate ocean acidification under variable light and flow regimes: Insights from an experimental approach.

The urgent need to remediate ocean acidification has brought attention to the ability of marine macrophytes (seagrasses and seaweeds) to take up carbon dioxide (CO2) and locally raise seawater pH via primary production. This physiological process may represent a powerful ocean acidification mitigation tool in coastal areas. However, highly variable nearshore environmental conditions pose uncertainty in the extent of the amelioration effect. We developed experiments in aquaria to address two interconnected goals. First, we explored the individual capacities of four species of marine macrophytes (Ulva lactuca, Zostera marina, Fucus vesiculosus and Saccharina latissima) to ameliorate seawater acidity in experimentally elevated pCO2. Second, we used the most responsive species (i.e., S. latissima) to assess the effects of high and low water residence time on the amelioration of seawater acidity in ambient and simulated future scenarios of climate change across a gradient of irradiance. We measured changes in dissolved oxygen, pH, and total alkalinity, and derived resultant changes to dissolved inorganic carbon (DIC) and calcium carbonate saturation state (Ω). While all species increased productivity under elevated CO2, S. latissima was able to remove DIC and alter pH and Ω more substantially as CO2 increased. Additionally, the amelioration of seawater acidity by S. latissima was optimized under high irradiance and high residence time. However, the influence of water residence time was insignificant under future scenarios. Finally, we applied predictive models as a function of macrophyte biomass, irradiance, and residence time conditions in ambient and future climatic scenarios to allow projections at the ecosystem level. This research contributes to understanding the biological and physical drivers of the coastal CO2 system.

Geochemical dynamics of phosphorus and metals in sediments of a shallow coastal lake (Xuño Lake, Galicia-NW Iberian Peninsula)

The shallow lakes are important freshwater ecosystems, since they support much of biodiversity and ecosystem services of life on land. Shallow lakes are highly dynamic ecological entities that can exist in several alternative stable states through regime shift caused by a natural or human disturbance that exceeds ecological thresholds for biological communities composition and structure equilibria. The sediment as a reservoir has a key role in the limnological regulation of wetlands linked to the fluxes of nutrients and elements in the biogeochemical interplay with the water and macrophytes. For this reason, the role of sediment in the limnology of the shallow coastal lake of Xuño (NW Iberian Peninsula) was explored by seasonally monitoring the chemical composition of water and sediments, also according to macrophyte species. The shallow depth determines the high availability of light in the bottom and a well-mixed water column maintain the surface of the water–sediment interface oxygenated. The oxic conditions of the bottom implies a top-down regulation of the water column in the Xuño shallow lake that limits the diffusion of phosphorus and trace metals (Fe, Mn, Cu, and Co) to the water, buffering eutrophication or contamination levels by immobilization in the sediments. In fact, the concentration of Hg in the lake water in spring, and also its bioavailability, are high due to its release from the sediment in suboxic conditions. The cover of helophyte species Phragmites Australis and Schoenoplectus Lacustris showed differences in the assimilation of organic monoester and diester phosphorus forms in the sediment. However, the water of the Xuño Lake shows an eutrophic status by the nutrient input associated with the birds populations as indicated by microbiological data.

An Ecopath perspective on the maximum sustainable yield of a macrophyte infested wetland in Eastern India

Wetlands are recognized as one of the most productive aquatic ecosystems. This high productivity supports its enormous biodiversity, aiding a scope for the small scale fisheries within it. Basically, these wetlands act as platforms for culture-based fisheries (CBF) i.e practice of stocking fish seeds and harvesting the grow out fishes at later. Often in tropical wetlands, the high nutrient load and high temperature enable the luxurious growth of macrophytes. Moreover, this macrophyte infestation is considered as a bottleneck for wetland managers. Facing a similar situation our studied Beledanga wetland is a macrophyte-infested wetland and the invasive Eichhornia crassipes is the most dominant macrophyte species. Owing to the macrophyte problem, Grass carp have been stocked in it as a biocontrol agent, as grass carp is a known biocontrol agent for the macrophyte infestation situation and simultaneously it will raise the fish production. To ensure maximum sustainable production from the wetland by harnessing with the available resources, it is necessary to acquire knowledge about the system’s ecological status and its ecological networks. Thus, the Ecopath based mass-balanced model is one of the best suitable tools to know about the ecological organization of this Beledanga wetland. Considering the available data (observational and literature data), this study has constructed a mass-balanced Ecopath model with 14 functional groups including all fish groups, birds, plankton, benthos and detritus. It has been found that the zooplankton and benthos are the most utilized group and the birds are the keystone group in this wetland system. This wetland possesses a lower transfer efficiency as well as a low Finn’s cycling index (0.224%). The system is found as an immature system with moderate ascendancy and system reserve (overhead). Moreover, concerning the ecologically sustainable production from this wetland more virtual mass-balanced models were developed (i) to evaluate the optimum grass carp stocking to manage the macrophyte population and (ii) to assess the impact of the Eichhornia on the system functioning. The results show that the system can harbour 1.5 times more grass carp biomass than the present without hampering sustainability. Concerning the impact of Eichhornia, it has been noticed that this macrophyte affects the maturity and transfer process of the system. Moreover, its huge biomass only accumulates more detritus in the ecosystem.

Structure of the macrophyte communities of small rivers in Saratov under anthropogenic load

The article presents the results of investigations of the flora of small rivers within the city of Saratov (Yelshanka, Nazarovka, 1st Gusyolka, and 2nd Gusyolka). The species composition of aquatic plants of the streams studied is represented by 37 macrophyte species belonging to 23 genera, 17 families and three divisions (Charophyta, Polypodiophyta, and Magnoliophyta). The families Potamogetonaceae, Cyperaceae and Lemnaceae predominate by the number of represented species. The values of the Menchinik index indicate that the greatest floristic diversity is characteristic of the Yelshanka and Nazarovka rivers (3.1 and 3.4, respectively). The species composition of aquatic plants of the studied rivers within the urban area has a low similarity coefficient with the flora of rivers with relatively low anthropogenic load. Hydrophytes are the most numerous ecological group (22 species). According to the Paley–Kownacki dominance index, among the macrophytes of the studied rivers, most species are subdominant (57.28%) (Potamogeton perfoliatus, Typha angustifolia, Lemna trisulca, etc.). 37.18% (Phragmites australis, Potamogeton pectinatus, Lemna minor, Ceratophyllum demersum) belong to dominants, and the rest (11.54%) is defined as subdominants of the first order. Exceptional predominance is characteristic of Ceratophyllum demersum and Phragmites australis, which acted as dominants in all studied rivers. A significant part of the rivers is characterized by a low degree of overgrowth by hydrophilous vegetation, from slightly overgrown to not overgrown. The main types of distribution of aquatic and riparian-water vegetation are belted and fragmentary. Macrophyte communities are characterized by a simplified structure (one- or two-tiered), with absolute predominance of one plant species and the presence of two to four associated species with low values of projective coverage. The results of our calculations of indices (macrophyte index for small rivers (Sm), Indice Biologique Macrophytique in Riviere (IBMR)) based on the structural parameters of macrophytes showed that the studied rivers have a satisfactory ecological status.

Ecological Dynamics of Macrophytes in Lentic Water Bodies: A Case Study in Valsad, Gujarat, India

We examined the occurrence of macrophyte diversity and its distribution in the selected lakes of Valsad district, Gujarat, India. There were two main objectives, first examine the macrophyte species diversity in the selected lakes using the Shannon-Wiener diversity index, and the second one was to investigate the impact of environmental parameters on the macrophyte diversity. The canonical correspondence analysis (CCA) was utilized to better understand the relationship between macrophyte communities and environmental conditions. The results showed that from the 50 macrophyte species recorded, 30 species were emergent, 06 species were submerged and 14 species were floating and the overall Shannon-Wiener diversity (H’) of water bodies ranged from 1.917 to 2.584. As per the Sorenson percentage similarity result, there was 80.3 % of an average similarity was present in macrophytes composition (p = 0.0039). The 14 (except phosphate and salinity) out of 16 selected physicochemical variables were statistically significant (p < 0.05) and mentioned in the CCA model, which revealed that macrophyte assemblage structure was strongly associated with Physicochemical parameters. Keywords: aquatic macrophytes, biodiversity, CCA, physicochemical variables, Valsad

A comprehensive health risk assessment associated with bioaccumulation of heavy metals and nutrients in selected macrophytes of Loktak Lake, Manipur, India.

The Loktak Lake, a Ramsar site in Northeast India, is known for its rich biodiversity that includes a variety of macrophyte species, most of which have not been studied for their phytoremediation capacities and potential toxicity via consumption of the edible species. Therefore, a comprehensive assessment was conducted to evaluate the accumulation of selected heavy metals and nutrients in 10 dominant macrophyte species growing in Loktak Lake and to assess the potential health risks associated with consumption of the edible plants. The concentrations of nutrients such as total phosphorus (TP), total nitrogen (TN), potassium (K), calcium (Ca), magnesium (Mg), and heavy metals such as copper (Cu), manganese (Mn), zinc (Zn), and iron (Fe) were found to be in the order of plant > sediment > water. The bioaccumulation factors (BAFs) revealed high efficiency of most plants to accumulate heavy metals and nutrients in their tissues from the lake water and sediments, indicating their potential to be used as phytoremediators. Translocation factors (TFs) were also estimated to determine the efficiency of the plants to translocate elements from root to shoot. Colocasia esculenta and Polygonum perfoliatum exhibited the highest BAF values, whereas Colocasia esculenta, Hedychium flavum, Phragmites karka, and Oenanthe javanica exhibited the highest TF values for most elements. Target hazard quotients (THQs) revealed potential health risks associated with one or more heavy metals in the plants, except for Zn, whose THQ values were below the level of concern in all the edible plant species. The hazard index (HI) signifying potential non-carcinogenic health risk from the combined effects of all the heavy metals was highest for Polygonum perfoliatum, indicating a potentially higher risk to health if this edible macrophyte is regularly consumed in higher quantities and may pose long-term health effects to the exposed population.