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9—15, 2003; ISSN 0006-3088. 13 different Characeae species were screened for allelopathic activity using agar-diffusion assays. Nine different Cyanobacteria, one diatom species and three Chlorophyceae were applied as target organisms. Whereas cyanobacte-ria were strongly inhibited by certain stoneworts, surprisingly no clearing of eukaryotic target...
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The iron phosphates coagulant is commonly used in lake restoration to improve water quality and eliminate cyanobacteria bloom. Nevertheless, the short-term abiotic environment transformation in particular inside macrophytes communities is still not sufficiently studied. The field experiments were carried out in mesocosms installed in Chara hispida...
Chara drouetii R.D. Wood, 1965 was recently collected during floristic surveys of aquatic macrophytes in the Yucatán Peninsula, Mexico. This discovery represents the first documented record for this species from the state of Quintana Roo, Mexico. This report extends the range of Chara drouetii by approximately 300 km east of the nearest known occur...
First study of new locality the Ein Qinia high mountain pool with charophyte algae in the Golan Heights region of Israel has been implemented for revealing of algal diversity and ecological assessment of the water object environment by chemistry and bio-indication methods. Altogether forty two species of algae including one of them macro-algae Char...
The iron phosphates coagulant is commonly used in lake restoration to improve water quality and eliminate cyanobacteria bloom. Nevertheless, the short-term abiotic environment transformation in particular inside macrophytes communities is still not sufficiently studied. The field experiments were carried out in mesocosms installed in Chara hispida...
Citations
... From the past few decades, seaweeds have been highly acknowledged to possess prominent biological activities, which include antineoplastic, antimicrobial and antiviral activities (Patterson, Larsen, Moore, 1994) due to their specific functional compounds (which are not available in land plants) (Pietra, 1997;Cabrita, Vale, Rauter, 2010). Particularly, seaweed of Chara genus (family: Characeae -charophyte green algae) possess to have antioxidant enzyme and allelopathic activities and lipid peroxidation capabilities along with high levels of photosynthetic pigment content (Berger, Schagerl, 2003). Earlier the experiment which we had performed has established the phytochemical analysis along with antioxidant activities of seaweed Chara baltica (Naidu et al., 2018). ...
For the first time, five known metabolites - 1 and 5 are reported from the ethyl acetate extract from seaweed Chara baltica (EAE). Both the metabolites and EAE were screened against free- radicals, α-glucosidase enzyme and glycaemia in albino rats. 4, 5 and EAE depicted significant antiradical and α-glucosidase inhibitory profile. Particularly, compound 5 showed equivalent inhibition of superoxide free radical as that of the standard drug with IC50 value of 32.0 µg/mL. In addition, the EAE (200 mg/kg b.w) revealed significant reduction in plasma glucose, body weight, total cholesterol, total glycerides and LDL levels in Streptozotocin-induced diabetic rats. The HDL levels were markedly augmented in EAE treated diabetic rats, when compared with control group. EAE abolished the increased lipid peroxidation content in both liver and kidneys. The histopathological examination of pancreas of EAE protected the Langerhans islets with the number of islet cells were found statistically significant, when compared to diabetic control pancreas. This is the first in vitro and in vivo antidiabetic report on C. baltica.
... Similar to other macrophytes, N. obtusa could compete with phytoplankton for available habitat space, nutrients, and light (Sand-Jensen & Borum, 1991). Additionally, N. obtusa, like other charophyte species, has been shown to produce and secrete allelopathic compounds that selectively inhibit phytoplankton taxa (Berger & Schagerl, 2003, 2004. N. obtusa typically grows in tangled masses that can form dense benthic mats; a life habit conducive to displacing other macrophyte species. ...
... In a study from N. obtusa's native range, Berger and Schagerl (2004) demonstrated that N. obtusa can secrete allelopathic compounds, which selectively inhibited growth of several phytoplankton strains within a laboratory setting. Furthermore, N. obtusa has been observed to grow taller than other Characeae species. ...
... that a positive co-occurrence relationship exists between these taxa in Lake Scugog. Further studies would need to be done to explore this relationship, but Berger and Schagerl (2004) Note: All variables were log (x + 1) transformed prior to analysis (n = 232). ...
• Nitellopsis obtusa was first reported in North America in 1974. The overall ecological threat that N. obtusa poses towards freshwater ecosystems in its non-native range is thought to be similar to other invasive macrophyte species. However, few studies have evaluated the impacts to aquatic communities upon successful establishment of this species in North America. Despite N. obtusa being a non-native invasive species in North America, it is considered a beneficial macrophyte within its native range in Eurasia
• We evaluated the impacts associated with the non-native invasive charophyte N. obtusa on the lower aquatic food web (LAFW) communities (phytoplankton, macroinvertebrates, and macrophytes) in a large, shallow lake in Ontario, Canada. To tease apart abiotic and biotic factors that influence LAFW species assemblages, a generalised linear latent variable model (GLLVM) was used.
• Over the course of the 4-year study period, N. obtusa abundance significantly increased throughout the lake (pairwise comparison, p < 0.001) and notable shifts in community composition occurred across years (PERMANOVA, p < 0.001), especially for the phytoplankton and macrophyte communities.
• Nitellopsis obtusa was also found to be associated with a decline in diversity, where Simpson's diversity indices across all LAFW communities decreased as a function of increasing N. obtusa biomass. The GLLVM analysis revealed significant negative associations between N. obtusa and the majority of LAFW taxa. Most notably, there was a significant (p < 0.001) negative relationship between Myriophyllum spicatum, a previously established non-native invasive macrophyte, and N. obtusa. The GLLVM model also demonstrated that N. obtusa had positive co-occurrence relationships with other members of the macrophyte community including Utricularia vulgaris, Najas flexilis, Potamogeton crispus, and Stuckenia pectinata.
• These results show for the first-time significant impacts to the LAFW in an invaded ecosystem, which raises major concerns for fish communities that depend on the LAFW for food and habitat. Further studies are necessary to confirm the extent of these impacts in other invaded lakes.
... Similar Although many aquatic and terrestrial plants, and marine algae have been tested to control Microcystis harmful blooms; freshwater macroalgae are very little studied. To our knowledge, the freshwater Chara genus is the most recognized in bioassays that have tested the algaecide effect on Microcystis spp (Berger and Schagerl, 2004). ...
The extracts of Chara vulgaris (a green macroalgae) were tested to explore its algicidal potential on Microcystis aeruginosa growth. Firstly, the anticyanobacterial effect of both macroalgae aqueous (MAA) and macroalgae etyl acetate (MEA) extracts against M. aeruginosa was assessed using both the paper disc diffusion and microdilution methods. Minimum inhibitory concentrations (MIC) and minimum algicidal concentrations (MAC) were evaluated. Secondly, the growth of M. aeruginosa in response to the MEA extracts was investigated in an experimental bioassay. To reveal the potential allelochemicals, total phenols (TPs), total flavonoids (TFs), tannins (TTs) were analyzed in both MAA and MEA extracts. The identification of the phenolic compounds in MEA extracts was performed by high-performance liquid chromatography (HPLC). The results from the bioassay demonstrated that MEA extracts inhibit the growth of M. aeruginosa in a concentration dependent way. The highest inhibition rate (IR) exceeds 83% on day (d) 4 of experimentation, and achieved (97.98%) on 7-d. HPLC analysis revealed seven phenolic compounds known as effective allelochemicals. Overall, the obtained results demonstrate that MEA extracts might be proposed as a potential allelochemicals, and it can be considered as an ecofriendly alternative algaecide to control Microcystis blooms in the eutrophic water bodies.
Keywords: Chara vulgaris, natural algaecides, allelochemicals, M. aeruginosa, inhibitory effect
... We found that Chara globularis extracts were able to inhibit the growth of both Aphanizomenon gracile and Microcystis aeruginosa. Similarly, Berger and Schagerl (2004) have demonstrated the inhibitory effect of living thallus and extracts of Chara globularis on the growth of several cyanobacterial species, including Microcystis aeruginosa. In addition, Jasser (1995) has revealed a reduction of phytoplankton biomass in the presence of Chara globularis aqueous extract. ...
Macrophytes have often been considered as a prospective tool for the elimination of cyanobacterial bloom, because they may produce chemical compounds that outcompete bloom-forming cyanobacteria. However, a comprehensive, unbiased overview of evidence to support this is missing. Moreover, studies into the effects of individual macrophyte species have often used different methodologies and, thus, cannot be compared. Herein, we firstly carried out a systematic review of studies into the effects of macrophytes on the growth of bloom-forming cyanobacteria. Secondly, we carried out an experiment into the effects of aqueous and ethanol extracts from 19 macrophyte species on the growth of two of the most common cyanobacteria, Aphanizomenon gracile and Microcystis aeruginosa, using a uniform methodological approach. The systematic review revealed that most of the 69 macrophyte species previously studied have shown a combination of inhibitory, stimulatory, and neutral effects. In our own experiment, an inhibitory effect was exhibited only 15 times out of 532 experimental variants, specifically by Chara globularis, Ceratophyllum submersum, Elodea nuttallii, Hydrilla verticillata, Myriophyllum heterophyllum, M. spicatum, and Vallisneria americana. Put together, these results indicate that the practical application of chemical compounds produced by macrophytes to eliminate cyanobacterial bloom may have lower prospects than previously anticipated.
... In contrast, SAV typically remains widely distributed in clear lakes and helps maintain water clarity by stabilizing sediments and storing nutrients (Søndergaard et al., 2003). Charophytes (Chara spp.) often accompany clear-water conditions and are believed to release algal toxins (Berger & Schagerl, 2004) and provide refuge for zooplankton, which may further reduce the phytoplankton population and help stabilize clear-water conditions. Mathematical models provide a useful framework for understanding ecosystem dynamics, including the difficulty of restoring degraded systems that exhibit alternative stable states. ...
Successful conservation of ecosystems exhibiting alternative stable states requires tools to accurately classify states and quantify state transition risk. Methods that utilize early warning signals are promising approaches for helping managers anticipate impending state transitions, but they require high‐resolution temporal or spatial data for individual sites, and they do not directly implicate causes or quantify their impacts on transition risk. There is need for a modelling approach that can assess state transition risk with lower resolution temporal data, identify drivers of state transitions and assess the impact of changes in these drivers on the persistence of ecosystem states.
We developed a novel, integrated modelling framework that (a) classifies states in a way that reflects the qualitative dynamics of catastrophic regime shifts, (b) estimates state transition probabilities and (c) uses annual survey data to identify top predictors of state transitions and quantify their effects on transition risk. We applied our model to short time series from 123 shallow lakes that exhibit clear‐ and turbid‐water alternative stable states.
We found that clear lakes were more likely to transition to the turbid state as total phosphorus levels increased or occurrence of submerged vegetation decreased. Additionally, increases in planktivorous or benthivorous fish biomass elevated transition risk. Too few turbid‐to‐clear transitions were observed to identify predictors of transitions in this direction.
Synthesis and applications. Our study will inform conservation and management strategies for ecosystems exhibiting alternative stable states by providing a new tool to accurately classify states, compare state transition risk among sites based on resilience and system perturbations, and identify key variables to target to prevent undesirable transitions. Although we focus on shallow lakes as a case study for our modelling approach, we emphasize that our framework is applicable to any ecosystem known to exhibit alternative stable states.
... With the re-establishment of underwater vegetation, submerged macrophyte growth takes advantage against phytoplankton growth (Phillips et al., 2016), and thus clear water is stabilized by sustained macrophyte domination (Cristofor et al., 2003;Hilt et al., 2006;Hilt, 2015). The spatial tightness of habitat zonation along the depth is further relevant when considering allelopathic substances which may suppress the growth of certain species within the same assemblage, both within the phytoplankton and the macrophyte community, but can also occur also between species of algae and macrophytes (Van Donk and Van de Bund, 2002;Gross, 2003;Legrand et al., 2003;Berger and Schagerl, 2004;Hilt and Gross, 2008;Mulderij et al., 2009;Chang et al., 2012). Some of these studies assume that allelopathically active macrophytes contribute to stabilize sustained macrophyte growth and thus clear-water state in shallow lakes. ...
The perspective on water transparency changed since the early days of limnology from being a physical parameter of optical water property to an ecological indicator tracking algal turbidity due to eutrophication or an overall success of sustained lake restoration in the late 60ies to 80ies. In modern cities, where ecosystems are commonly deteriorated by man-made modifications, water transparency offers a great opportunity to the public to raise socio-ecological consciousness concerning urban green-blue spaces. We thus re-emphasize water transparency as a key indicator of multi-functional value when assessing an oxbow lake of the riverine floodplain in Vienna, the Alte Donau. Our study covers the eutrophication from 1987 to 1994 due to the inclusion of the riverine landscape in the urban area, the following lake restoration with an ecosystem shift from a nutrient-rich, algal-turbid water body to a nutrient-poor, clear-water macrophyte controlled system and the impact of global warming in recent decades. We used light attenuation profiles to identify depth layers of specific ambient light requirements for photosynthetic domains (phytoplankton and submerged macrophytes), and to interpret Secchi measurements. Here, we calculated the depth at 1% (minimum light requirements for phytoplankton growth as euphotic depth), 3% (minimum light requirements for macrophytes as maximum macrophyte colonization depth), and 12% (preferred light requirements for phytoplankton development) of surface ambient light. A Secchi disk water transparency of 1.5 m (“lake bottom view”), judged as good water quality by human perception, refers to mesotrophic conditions with a maximum colonization depth for macrophytes exceeding the mean lake depth in Alte Donau. Water clarity required for sustained macrophyte growth, in particular for favoring bottom-dwelling Chara meadows instead of tall-growing Myriophyllum spicatum, is 3.5 m Secchi depth and thus exceeds by far water clarity requested due to bathing aesthetics. Global warming, mirrored by an advanced warming in spring seems to favor significantly a higher yield of macrophytes mainly built up by Myriophyllum at the expense of the yield of algae. The prolongation of the summer period above 21°C, however, coincides with lowered Secchi transparency. Water visibility during the hot season thus seems to be slightly hampered against lake restoration efforts by global warming.
... Macrophytes are important to the maintenance of dynamics and have complex relationships to other communities (Thomaz 2002, Van Donk andVan de Bund 2002). Unlike submerged angiosperms, Characeae can rapidly colonize aquatic ecosystems and form extensive meadows, even under conditions of low concentrations of phosphorus and nitrogen (Blindow 1992, Berger andSchagerl 2004). The assimilation of resources is also different. ...
... Chara showed fewer abundant genera than Nitella, possibly explained by the release of secondary metabolites, as reported in previous studies (e.g., Mulderij et al. 2003, Berger and Schagerl 2004, Hilt 2006. The Chara biomass was negatively associated with the genus Spirogyra, which has a high biomass, is commonly found forming dense banks, and is often considered metaphyton (Pikosz and Messyasz 2015). ...
We analyzed structural attributes (epiphyton composition, richness, density, biomass, and life forms) involved in interactions between the epiphyton and Characeae (Chara and Nitella) in 19 tropical reservoir environments, 7 with the presence of Chara, 7 with Nitella, and 5 with both genera. A sampling station measuring 4 m² was defined in each environment for the collection of abiotic and biotic data without temporal repetition. Univariate and multivariate analyses were performed for the characterization of each environment. Regression analysis and partial redundancy analysis (pRDA) were used to test the substrate–epiphyton relationship. The substrate biomass was significantly associated (p < 0.05) with epiphyton biomass, total density, and filamentous forms. The pRDA revealed that epiphyton biomass was related to the 2 substrates, whereas composition was related to the environment (p < 0.05). A negative association was found between Chara and Spirogyra (36.2%). Nitella was positively associated with the genera Lyngbya, Oedocladium, and Oedonogium and negatively with Staurastrum, whose genera together accounted for 12.9% of the biomass of the community. Characeae (Chara and Nitella) did not exert a direct influence on total richness or composition; these attributes were explained by environmental factors. Chara and Nitella biomass had a positive interaction with epiphyton biomass and density, but each substrate promoted specificity and distinct intraspecific relationships in the epiphytic structure in the tropical reservoir environments.
... Water hyacinth reduced the feeding rate of an insect pest, Spodoptera litura (Lepidoptera: Noctuidae), and was considered as a potential bioinsecticide for the management of this insect [9]. Among 13 different Chara populations screened against microalgal strains including cyanobacteria and eukaryotic microalgae, 10 inhibited growth of cyanobacteria [10]. After one day, water lettuce and duckweed had a significant negative effect on germination and root growth of a weed, common lambsquarters (Chenopodium album, Caryophyllales: Amaranthaceae) [11]. ...
Aquatic weeds such as muskgrass (Chara spp.), water hyacinth (Eichhornia crassipes), water lettuce (Pistia stratiotes), hydrilla (Hydrilla verticillate), filamentous algae (Lyngbya wollei), and duckweed (Lemna minor) thrive in farm canals within the Everglades Agricultural Area of South Florida. Their presence, particularly during the summer months is an environmental concern with regards to water quality, in addition to being a nuisance because of their ability to multiply and spread rapidly in open waters causing restricted drainage/irrigation flow and low dissolved oxygen levels. Chemical control is effective but can have undesirable off-target effects, so reduced herbicide use is desirable. Hence, need exists to discover ways in which these weeds could be best managed or utilized. The objective of this research was to evaluate the allelopathic effect of these weeds to determine their use as potential biopesticides. Six aqueous extracts were tested against 100 bacterial strains isolated from plants and soil to evaluate their antimicrobial activity. These extracts were also used to determine their insecticidal and antifeedant effects on fall armyworm (FAW, Spodoptera frugiperda). Both extracts and powder form of the aquatic weeds were tested for their herbicidal activity towards seed germination and growth of three common terrestrial weed species. At a dilution of 1:100 and 1:1,000, none of the aquatic weeds inhibited in-vitro growth of the bacterial strains, with one exception (filamentous algae extract at 1:100 reduced growth of one bacterial isolate by 54%). Water lettuce reduced the survival rate of FAW by 14% while hydrilla and duckweed caused 11% and 9% reduction of FAW growth, respectively. Powdered duckweed inhibited the growth of nutsedge by 41%, whereas filamentous algae powder and extract reduced germination of amaranth by 20% and 28%, respectively. Harvesting these weeds and converting them into useable compounds could not only eliminate the in situ farm canal and water quality problems but also result in development of new soil amendments or biopesticides.
... Another potential facilitation mechanism involves allelopathy. Charophytes like N. obtusa are known to exude bioactive substances that inhibit select phytoplankton species, to minimize competition for nutrients and light (Berger and Schagerl 2003;Berger and Schagerl 2004). Studies have shown that N. obtusa can produce and exude allelopathic substances that inhibit some aquatic plants and algae while facilitating others (Blindow et al. 2014). ...
... Studies have shown that N. obtusa can produce and exude allelopathic substances that inhibit some aquatic plants and algae while facilitating others (Blindow et al. 2014). In one study, bioactive exudates from N. obtusa inhibited several phytoplankton taxa, but not Microcystis aeruginosa (Berger and Schagerl 2004). Therefore, it is possible that Microcystis spp., being tolerant of both chloride and allelopathic compounds produced by N. obtusa, are able to erupt in blooms in Lake Scugog simply because competition from other phytoplankton has been reduced. ...
This study was conducted in Lake Scugog, a large, shallow reservoir in Ontario, Canada. Historically, Lake Scugog has been a macrophyte-dominated ecosystem with a productive fishery. In recent years, periodic Microcystis blooms have erupted coinciding with the discovery of the non-native macroalga Nitellopsis obtusa in the lake. From 2016 – 2018, we conducted field surveys to assess the physical, chemical, and biological conditions across 12 sites spanning the lake. All study species (N. obtusa, Dreissena polymorpha and Microcystis) increased from 2016 to 2018. To determine potential biotic and abiotic drivers of Microcystis blooms, a structural equation modelling (SEM) approach was used. The SEM (r<sup>2</sup> = 0.27, p < 0.05) revealed several positive (precipitation, chloride, depth, and N. obtusa) and negative (Total Nitrogen) explanatory variables for Microcystis biomass. The only statistically significant biotic driver was N. obtusa, which was a positive explanatory variable for both D. polymorpha and Microcystis. Future work will test the efficacy of the SEM model across Ontario lakes to confirm the facilitative role of N. obtusa on D. polymorpha and Microcystis populations.
... Many studies assessed the biological effectiveness of The Green Algae in the world including the study of Dhillon et. al (1982), Marten (1986), Berger& Schagerl (2004) and Ghazal et. al (2004). ...
