Chara Hispida Research Articles

Direct analysis of algae for determination of major and minor elements using energy dispersive x-ray fluorescence (EDXRF)

The current study aimed to determine the major and minor elements in different algal species using energy dispersive x-ray fluorescence (EDXRF). Eight microalgae were isolated, and the dry powder of biomass was pressed for EDXRF. The results showed all chemical compositions in each of the isolates. The major elements were detected as Ca, K, Cl, Si, Mg, and Mn, respectively, with high concentrations in percentages for most algal species including Chara hispida, Chara spp, Chlorella vulgaris, Chlorella spp, Chlorella spp, and Spirogyra turfosa. The minor elements with low percentages were detected as Mn, S, Fe, Al, P and Sr. Whereas the major elements for Spirulina platensis and Nostoc punctiforme were detected as Fe, K, S, the minor elements were seen to include Ca, Cl, Si, Mg, and Mn. There are very few studies that determine the elements in microalgae with EDXRF, which is a rapid, easy method to determine what components and in what quantities they are contained to be used (no chemical pre-treatments are required). Algae contain elements like iron, and calcium, which are vital microelements for dietary intake and metabolism in humans. Algae could be useful if further studies are done on the efficiency of microalgae for calcium and iron absorption in human subjects.

Early Pleistocene charophyte flora from Dursunlu (Ilgın Basin, Turkey): palaeoecological implications

Here, a charophyte assemblage from lower Pleistocene deposits at the coal mine locality of Dursunlu (Ilgın Basin, Turkey) is described and illustrated for the first time. The assemblage is composed of 11 species recovered from 50 samples taken from an 18 m-thick sedimentary sequence. The base of the sequence is dominated by lignites and organic-rich claystones/siltstones with root marks attributed to palustrine facies. The charophyte assemblage in this palustrine interval is dominated by Chara vulgaris and C. globularis. The upper part of the section is constituted by light grey-yellowish marls, siltstones and a limestone bed related to shallow lacustrine deposits. Two charophyte species dominate this lacustrine interval, Chara hispida and Nitellopsis obtusa, which occurred in intervals in association with Chara pappii, Chara molassica var. notata, Chara sp.1, Chara sp.2, Sphaerochara prolifera, Sphaerochara intricata and Lychnothamnus barbatus var. antiquus. The palaeoenvironmental characteristics and evolution of the Ilgın palaeolake during the Early Pleistocene (Günz glaciation) are inferred from a facies analysis and the ecological requirements of the charophyte assemblages. The results suggest that during this glacial period, the Ilgın Basin was occupied by a very shallow eutrophic lake with a dense palustrine vegetation belt, which evolved to a shallow (2–15 m deep), stable, oligotrophic, alkaline and oligohaline lake. The increase in water availability in the palaeolake can be related to climatic oscillation during the Günz glaciation. Finally, the lake depocentre migrated towards the NW due to tectonism, and these deposits were later subjected to intense pedogenic alteration.

A modern snapshot of the isotopic composition of lacustrine biogenic carbonates – records of seasonal water temperature variability

Abstract. Carbonate shells and encrustations from lacustrine organisms provide proxy records of past environmental and climatic changes. The carbon isotopic composition (δ13C) of such carbonates depends on the δ13C of dissolved inorganic carbon (DIC). Their oxygen isotopic composition (δ18O) is controlled by the δ18O of the lake water and by water temperature during carbonate precipitation. Lake water δ18O, in turn, reflects the δ18O of atmospheric precipitation in the catchment area, water residence time and mixing, and evaporation. A paleoclimatic interpretation of carbonate isotope records requires a site-specific calibration based on an understanding of these local conditions. For this study, samples of different biogenic carbonate components and water were collected in the littoral zone of Lake Locknesjön, central Sweden (62.99∘ N, 14.85∘ E, 328 ma.s.l.) along a water depth gradient from 1 to 8 m. Carbonate samples of living organisms and subfossil remains in surface sediments were taken from the calcifying alga Chara hispida, from bivalve mollusks of the genus Pisidium, and from adult and juvenile instars of two ostracod species, Candona candida and Candona neglecta. Our results show that neither the isotopic composition of carbonates nor the δ18O of water vary significantly with water depth, indicating a well-mixed epilimnion. The mean δ13C of Chara hispida encrustations is 4 ‰ higher than the other carbonates. This is due to fractionation related to photosynthesis, which preferentially incorporates 12C into the organic matter and increases the δ13C of the encrustations. A small effect of photosynthetic 13C enrichment in DIC is seen in contemporaneously formed valves of juvenile ostracods. The largest differences in the mean carbonate δ18O between species are caused by vital offsets, i.e., the species-specific deviations from the δ18O of inorganic carbonate which would have been precipitated in isotopic equilibrium with the water. After subtraction of these offsets, the remaining differences in the mean carbonate δ18O between species can mainly be attributed to seasonal water temperature changes. The lowest δ18O values are observed in Chara hispida encrustations, which form during the summer months when photosynthesis is most intense. Adult ostracods, which calcify their valves during the cold season, display the highest δ18O values. The seasonal and interannual variability in lake water δ18O is small (∼ 0.5 ‰) due to the long water residence time in the lake. Seasonal changes in the temperature-dependent fractionation are therefore the dominant cause of carbonate δ18O differences between species when vital offsets are corrected. Temperature reconstructions based on paleotemperature equations for equilibrium carbonate precipitation using the mean δ18O of each species and the mean δ18O of lake water are well in agreement with the observed seasonal water temperature range. The high carbonate δ18O variability of samples within a species, on the other hand, leads to a large scatter in the reconstructed temperatures based on individual samples. This implies that care must be taken to obtain a representative sample size for paleotemperature reconstructions.

A quantitative method to analyse the sexual development of charophytes (Charophyceae): a baseline for phenological studies

ABSTRACT Traditionally, gametangium morphology has been considered an important feature in the taxonomy of charophytes (family Characeae), although its dimensions change notably with development. We present a methodological approach based on empirical data to describe the development of charophyte sexual organs. This method was tested in Chara hispida, C. aspera and C. canescens from Mediterranean brackish ponds. Five shoots per species and sampling date were collected on 19 dates during 2015 and observed under a stereomicroscope to measure the external diameter of antheridia, and the length and width of oogonia. Gametangial growth adjusted to a logarithmic model (a first period of rapid increase, followed by a slow growth period), with gametangia sizes reaching species-specific maxima. For oogonia, a logarithmic model also described the length-width relationship: a first period of elongation, followed by a swelling process related to ripening. We applied the derivative function to find the point when length and width increased equally. At greater width values (≥420 µm in C. hispida, ≥330 µm in C. aspera, ≥225 µm in C. canescens), width increased faster than length, and oogonia started to swell. Data from a single date, at the most appropriate moment based on the phenology of each species, also provided a good fit and a similar size threshold to distinguish non-swollen from swollen oogonia. This cost-effective method was valid for the three Chara populations, being particularly useful for phenological studies if used in combination with other criteria. We highlight the importance of standardizing these criteria before addressing relevant ecological questions.

Summer temperatures and environmental dynamics during the Middle Würmian (MIS 3) in the Eastern Alps: Multi-proxy records from the Unterangerberg palaeolake, Austria

Several millennial-scale warm phases perturbed the glacial climate during Marine Isotope Stage 3 (MIS 3, ca. 57–29 ka BP). Little is known about the impact of these climatic changes on Alpine ecosystems due to the sparsity of undisturbed sediment records in the Alps and their foreland. In this study, multiple sediment-archived proxies (sediment geochemistry, stable oxygen and carbon isotopes of autochthonous carbonate, and subfossil remains of macrophytes and aquatic invertebrates) were examined in five drill cores from an ancient inner-Alpine lake at Unterangerberg (Eastern Alps) to reconstruct the palaeolake environment and to estimate summer temperature changes for the first half of MIS 3. The lacustrine sedimentation in the basin began ca. 54.6 ka, tentatively correlated with the start of Greenland Interstadial (GI) 14. We identified three distinct phases in the development of the lake. (1) A cold, oligotrophic water body influenced by snow/glacier meltwater ca. 54.6–52.2 cal ka BP. (2) A clear-water, macrophyte-dominated, productive lake ca. 52.2–44.9 cal ka BP. Submerged macrophytes were dominated by the charophyte alga Chara hispida and chironomid assemblages – by Corynocera ambigua, which is absent from the present-day fauna of the Alpine region. (3) A turbid-water, less productive lake ca. 44.9–41.5 cal ka BP. This shift towards a turbid-water state, as evidenced by the drastic reduction in the abundance of submerged macrophytes and associated invertebrates, likely occurred due to increased input of meltwater. The regime shift is tentatively correlated with the start of GI 11, for which the highest temperatures of the studied MIS 3 interval are inferred. Chironomid-based reconstructions of mean July air temperatures provide interstadial temperature estimates between ca. 11 and 12.5°C (i.e. ca. 5–6°C below present-day values), which concurs with reconstructions available from the northern Alpine foreland. Cooler July temperatures (ca. 9–10°C) are reconstructed for MIS 3 stadials. The Unterangerberg lacustrine records provide valuable new insights into MIS 3 climate dynamics inside the Eastern Alps and contribute to a better understanding of the effects of climate change on the Alpine environment.

Sediment underneath charophyte meadows is enriched in viable ephippia and enhances the benthic periphytic biofilm

We contribute to the knowledge of charophyte meadows as key components of aquatic systems by analysing how they affect wetland sediments. We performed a factorial-design experiment with limnocorrals (outdoor mesocosms) in a Mediterranean protected wetland with presence or absence of charophytes [Chara vulgaris (CV) and Chara hispida (CH), planted from cultures or recruited in situ from germination of their fructifications]. The first 1 cm-surficial and 2 cm-bottom sediment layers were analysed for cladoceran ephippia, ostracods valves, benthic community of bacteria and periphytic biofilm, and charophyte fructifications. In the surficial sediment, the ephippia density was fourfold higher in the conditions with charophytes than in sites with no-charophytes and higher apparent viability was found. The surficial sediment periphyton biofilm was composed mainly of diatoms, with tenfold higher biomass underneath charophytes, and a much diverse community. The specific microhabitat generated by each charophyte species was reflected in the different abundances and relationships between the analysed components, firstly establishing a divergence with the sediment without meadows and, secondly, a distinction between the meadows of CH and CV that exhibit particular morphology-architecture, might exudate different metabolites and might have different allelopathic capacities over microalgae and microinvertebrates. Thus, the charophyte–sediment tandem is relevant for biodiversity and habitat conservation.

In-situ behavioural response and ecological stoichiometry adjustment of macroalgae (Characeae, Charophyceae) to iron overload: Implications for lake restoration

Eutrophication of water bodies markedly reduces their recreational and economic use, which in turn compels those interested to pursuing prompt and effective restoration. This also applies to waters with a moderate pool of biogenic resources which, following temporarily increased nutrient alimentation from the catchment area may become eutrophic. The in-situ experiment tested the impact of chemical restoration on benthic macroalgae (Chara hispida L.) found in meso-eutrophic waters. Commonly used doses of iron sulphate were applied, defined as Low – 10.8 g Fe m−2 and High – 21.6 g Fe m−2. It was presumed that the sudden shift of abiotic conditions of the environment will disturb growth and stoichiometry of the species. Analyses encompassed physicochemical water parameters (e.g. nutrient concentration, light availability), morphological features and elemental composition of the charophytes. Application of the coagulant caused shading of the plants and elimination of bioavailable phosphates from the water. This induced changes of behavioural ecology of the species, manifesting in elongation of the main axis and increase of the assimilation area (growth of branchlets and side-axes) as well as stoichiometric changes. It was found that shortage of phosphates in the water resulted in decreased phosphorus concentration in the thalli due to biological dilution. The increase of assimilation area and phosphorus dilution in the thalli have not been previously reported for charophytes. In this study, the qualitative transformation of the environment following application of iron as part of chemical lake restoration was evinced in significant ecological changes that adversely affected macrophytobenthos. The findings of the experiment can therefore be taken into account while planning restoration procedures, so as to preclude the risk of a negative trend of ecological changes.

Germination capability of four charophyte populations (Characeae) from Mediterranean brackish ponds under warm experimental conditions

ABSTRACTThe diaspore banks from two brackish ponds within the Albufera de Valencia Natural Park (Spain) containing oospores of Chara hispida, C. aspera, C. canescens and Nitella hyalina were analys...

The ‘Chara hispidaspecies complex’ (Charales, Charophyceae) kept in the Herbarium RO of the Sapienza University of Rome

Seventy-seven specimens of the Chara hispida species complex, stored in the Herbarium of Sapienza University of Rome (RO), identified over time with different names, have been examined. This paper ...

Changes in Chara hispida L. morphology in response to phosphate aluminium coagulant application

Abstract Progressing eutrophication of waterbodies requires measures to be undertaken that aim at halting or reversing negative changes in the environment. Chemical restoration is one of the most common methods used for lake treatment, where iron or aluminium phosphate coagulants are applied. However, their chemical qualities pose the risk of acidification and aluminium ion release, which become toxic in acidic conditions. The influence of coagulants on aquatic plants, including charophytes that are very valuable from the ecological perspective, is little recognised. For this reason, the aim of the research was to define changes in the growth pattern of the charophyte Chara hispida under the influence of an aluminium coagulant. The research was carried out in mesocosms (0.8 m3) located in situ in a lake. Polyaluminium chloride was applied once to each chamber in doses of 50.0, 100.0 and 200.0 ml m−3. Coagulant concentrations reflected aggressive restoration aimed at precipitation of phosphates, suspension and water colour at the same time. It was proved that the coagulant had inhibited the growth and slightly reduced the length of branchlets, and simultaneously elongated internode cells. Changes in the total length as well as the length of branchlets were caused by a strong pH decrease of the environment which simultaneously induced higher aluminium solubility and toxicity. Elongation of internode cells was caused by reduced light availability, resulting from high water turbidity in the first stage of coagulant’s application, and then from the charophytes’ thallus being covered by a coagulated suspension precipitated from water.

Effects of overabundant nitrate and warmer temperatures on charophytes: The roles of plasticity and local adaptation

Global change effects, such as warming and increases in nitrogen loading, alter vulnerable Mediterranean aquatic systems, and charophytes can be one of the most affected groups. We addressed the possible interaction between these factors on two populations of the cosmopolitan charophytes Chara hispida and Chara vulgaris. Populations were taken from two different environments, a nitrate-poor mountain lake and a nitrate-rich Mediterranean coastal spring. The laboratory experiment had a 2 × 2 factorial design based on two nitrate levels (similar to and double the local conditions) and two temperatures. Increased temperatures favoured the growth of the four populations, but an increase in nitrate did not have any effect on their growth or architecture. Both species took up and stored more nitrogen (measured as %N in plant tissue) when more nitrate was supplied, and warming favoured this increase in %N and, consequently, in N:P ratio. The effects of both factors depended on the local conditions where the populations originated and on the species. Chara vulgaris, a pioneer species, exhibited more phenotypic plasticity than C. hispida, and its ecotype from the coastal spring was better adapted to changes in temperature and nitrate level. These differential responses to warming conditions and nitrate pollution may modify charophyte diversity, which might be reflected in ecosystem performance, a matter of concern in vulnerable Mediterranean water bodies where these species co-occur.

On the tolerance of charophytes to high-nitrate concentrations

ABSTRACTCurrently a debate exists about whether the reduced growth of macrophytes with increased nitrogen loading in shallow ecosystems is determined by ecological or physiological factors. To discover whether nitrate in the water is detrimental per se to charophytes, we subjected Chara hispida and Chara vulgaris specimens, collected from two habitats greatly differing in nitrate concentrations (1.5 and 10 mg NO3-N/L, annual means), to a wide nitrate range (0.5–50 mg NO3-N/L) in two experiments (with free-floating specimens using nitrate as the sole N source, and with planted specimens, with other N sources in sediment). Charophytes grew both unplanted and planted in all treatments, and growth reductions occurred at the highest concentration in all cases. Some charophyte responses when faced with nitrate increases were different depending on (i) the species and (ii) population origin. Under the most realistic situation, the growth of both planted C. vulgaris populations was higher than that of C. hispida populations. C. vulgaris specimens from the nitrate-rich waterbody adapted best to the highest nitrate concentrations when they grew floating. Despite charophytes being vital and growing under high-nitrate concentrations in short-term laboratory experiments, such a situation in the environment may eventually not be sustainable, since ecological factors act in the field.

Bioaccumulation and toxicity studies of macroalgae (Charophyceae) treated with aluminium: Experimental studies in the context of lake restoration

The objective of this study was to examine the impact of aluminium on the perennial macroalgae Chara hispida L. and its bioaccumulation capacities. Aluminium (Al) was introduced into the environment in the form of polyaluminium chloride, an agent utilized in the restoration of waterbodies. Research was conducted in an experimental setting using mesocosms (volume 0.8m3) placed in the littoral zone of a lake with C. hispida. Three doses of the coagulant were applied, each with a different volume: low – 6.1g Al m−3, medium – 12.2gm−3 and high – 24.5g Al m−3. A significant acidification of environment was determined, which would imply the presence of toxic Al3+ ions. It has been demonstrated that aluminium penetrates and accumulates in the cells of the charophyte. This caused damage to the thalli, which manifested itself in chloroses, necroses, flaking of the cortex cells and softening of the thallus, whose severity was proportionate to the dose of the coagulant. The first negative signs were observed after 24h. The study shows that C. hispida is a poor accumulator of aluminium (bioconcentration factor < 200), while bioaccumulation capacity was inhibited at the concentration of approx. 2.0mg Al g−1 d.w. Accumulation in the thalli of the charophytes accounted for 58% of variation following removal of aluminium from the environment. The results of the experiment demonstrate a negative impact of aluminium on charophytes at concentrations used in aggressive restoration of lakes.

The inhibition of growth and oospores production in Chara hispida L. as an effect of iron sulphate addition: Conclusions for the use of iron coagulants in lake restoration

Charophytes, as a group of algae inhabiting waters characterized by varied fertility levels, represent highly critical attributes which are important for ecosystem services. One of the popular methods adopted for lake restoration is chemical inactivation of phosphates using iron coagulants. This paper presents the findings of laboratory experiments on the effects of iron sulphates on the growth and production of oospores in the charophyte Chara hispida L. In the course of the investigations, responses of this species to three dosages (Low, Medium, High) of iron (III) sulphate corresponding to the Fe concentrations of: 5.4, 10.8 and 21.6gm−3 Fe were analysed. The results demonstrated there was a decrease in the speed of growth of the major axis and reduced production of oospores on the one hand (differences were statistically significant only between High vs. Control), and stimulation of the development and growth of side branches of the first order on the other. Several factors that cause disorders in oospore growth and production were encountered, with a wide spectrum of physico-chemical changes in the water, which resulted in the charophyte thallus being coated by a brown colloid film (limiting access of light) and lowered pH level. The study showed that the use of iron coagulants for lake restoration poses a threat to the development (growth) of charophytes.

Time and heat for sexual reproduction: comparing the phenology of Chara hispida of two populations at different latitudes

Geographical location affects the main ecological factors driving the timing of plants’ life events. In addition, studying phenology is the simplest procedure to track current global warming and its effects on the success and survival of different populations of the same species. Little is known about the effect of water temperature and its corresponding accumulated heat on charophytes’ phenology. We compared differences in water temperature and sexual reproductive phenology of Chara hispida in two ponds of two countries located at different latitudes (Spain and Switzerland) over the same year. We estimated the accumulated heat required to develop from one phenophase to another (unripe/ripe gametangia and oospores). Curve fitting techniques on water temperature showed an advance of 26days in the Spanish spring onset. All phenological events happened for the first time around 40days earlier in the Spanish pond, agreeing with the Hopkins’ Bioclimatic Law prediction. C. hispida sexually reproduced in a daily mean temperature (DMT) range of 10–25°C and needed 600 growing degree-days (GDD) to ripen gametangia in the Spanish pond. The Swiss population required a higher DMT (15°C) to begin to reproduce, and ∼700GDD to initiate gametangia ripening. Temperature (as well as radiation) is one of the most important drivers of reproductive phenology, and accumulated heat is a better predictor than DMT for charophyte phenology. In the foreseeable warming scenario, we assume that C. hispida sexual events would advance by more than one month in Switzerland and expand at the end of the season, considerably lengthening its reproductive period.

Re-establishment of an extinct population of the endangered aquatic plant Potamogeton coloratus

Persistent soil seed banks play a key role in preventing extirpation of plants during periods of temporarily unsuitable conditions. They can serve as effective tools in achieving the goal of restoring wetland vegetation. Potamogeton coloratus, an aquatic plant of shallow, calcareous waters, has become critically endangered or vanished in large regions of its mainly European range. In the Czech Republic, it was observed in 1977 for the last time (prior to our restoration project) and has been classified as an extinct species. We successfully re-established one population of it, and also established a new one, both located in a fen complex from which it has been absent for more than 30 years. One population was restored in a desilted pool in which the species had occurred previously; the other was established in a newly created pool by means of transferring soil, including the seed bank, from a pool in which the species formerly occurred. Monitoring of these sites over subsequent years confirmed establishment and increase of the populations. Along with the target species, other rare, native aquatic plants (e.g. Utricularia vulgaris and Chara hispida) were found growing in the newly created pool. Propagules of these species were also detected in the sediment collected in the old pool prior the desilting and subjected to soil seed bank analysis. Although altogether 26 plant species were identified in the soil seed bank, no propagules of P. coloratus were detected, most likely due to their small number in the sediment analyzed.

(2303) Proposal to conserve the name Chara hispida (Characeae) with a conserved type

1 Senckenberg Forschungsinstitut, Senckenberganlage 25, 60325 Frankfurt am Main, Germany 2 Ernst-Moritz-Arndt-Universitat Greifswald, Biologische Station Hiddensee, 18565 Kloster, Germany 3 Borgsheider Weg 11, 45770 Marl, Germany 4 Universitat Rostock, Biowissenschaften, Albert-Einsteinstrasse 3, 18055 Rostock, Germany 5 Banchory, Stirling Acres Road, Kirkcudbright, DG6 4ES, Scotland, U.K. Author for correspondence: Thomas Gregor, thomas.gregor@senckenberg.de

Effects of UVB radiation exposure from the molecular to the organism level in macrophytes from shallow Mediterranean habitats

The available data on the effects of UVB radiation (UVBR) are scarce for submerged macrophytes, particularly charophytes. We studied the effects of UVBR on Chara baltica, Chara hispida, Chara vulgaris, Nitella hyalina and Myriophyllum spicatum, collected from shallow Mediterranean waterbodies. In a short-term laboratory experiment, we subjected these species to three different UVBR treatments corresponding to daily biologically effective integrated doses of 0, 1 and 6kJm−2. The analysed response variables were DNA damage, UV-absorbing compounds (both the methanol-soluble–SUVACs- and, for the first time in charophytes, the methanol-insoluble cell wall-bound fraction–WUVACs-), the stoichiometric composition, photosynthetic pigments, metabolic and growth rates and morphological architecture. UVBR induced harmful effects on DNA in all species, but M. spicatum appeared to be the most sensitive. The observed DNA damage only appeared to be UVB-dose dependent for C. vulgaris. The charophytes produced higher WUVACs levels and the angiosperm higher SUVACs levels. Higher chlorophyll and carotenoid concentrations were detected in the presence of UVBR, but their ratio was not modified by the applied treatments. The Chl a/b ratio decreased under UVBR in two charophyte species, whereas it increased in the angiosperm, which also exhibited a greater photosynthetic response. Relative growth rates were negatively influenced by UVBR, although the degree of this influence depending on the dose was different among species. UVBR modified growth patterns, particularly in those species exhibiting apical growth. We observed more species-specific differences than commonalities in the effects of and responses to UVBR across the investigated species.

The role of charophytes in a Mediterranean pond created for restoration purposes

A small, shallow basin was created and flooded with groundwater in a Reserve Area in Albufera de València Natural Park (AVNP) under the scope of a restoration program intended to mimic typical environments such as freshwater springs, abundant in the past but currently suffering from deterioration (desiccation, pollution, etc.), with the ultimate goal of increasing local biodiversity of submerged macrophytes, particularly charophytes. In this study we have monitored, from April 2009 (a few months after its first flooding) to September 2012, the dynamics of charophyte growth and related physical, chemical and biotic variables to highlight the factors determining charophyte success. Just after flooding, five charophyte species grew spontaneously when oospores germinated in the sediments. Chara hispida populations largely dominated the community and developed dense meadows that covered virtually the entire pond floor. Charophytes exerted a negative influence on phytoplankton densities, increasing water transparency. C. hispida stands precipitated substantial CaCO3 in the form of incrustations on the plants, accompanied by coprecipitation of inorganic phosphorus, maintaining low concentrations of soluble P in the water. Reduced groundwater inflow, increased salinity, nutrient concentration, turbidity and augmented feeding pressure by waterfowl, separately or by synergistic effects, considerably reduced charophyte development during the final year of the study; however, charophytes still represent one of the most extensive and dense stands of submerged vegetation within AVNP, verifying the achievement of the goal of the restoration plan. The knowledge obtained has allowed us to recommend several measures to counteract the decrease of charophytes, which can also be applied in other regions affected by the same stressors.

New Record of Chara Hispida (L.) Hartm. (Streptophyta: Charophyceae, Charales) from the Işıklı Lake (Turkey) and Critical Checklist of Turkish Charophytes

Chara hispida (L.) Hartm. has been found in the Isikli Lake (Western Anatolia). The specimens are described; distribution and ecology of C. hispida are discussed. The bio-indication shows that the Isikli Lake is mainly an oligotrophic state with a trend to a mesotrophic state, and fresh low-alkaline water with low to middle organic pollution. A check-list of charophytes was compiled. There are sixteen species of charophytes known from Turkey, including 13 species of Chara and 3 species of Nitella.