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Species of Ulva (Ulvaceae, Chlorophyta) are relatively common macroalgae in most coastal areas. In this paper, we examine Ulva in inland aquatic ecosystems to determine relationships between the chemical parameters of the water and the Ulva taxa present. Two groups of samples of freshwater Ulva were selected from: (i) habitats with high salinity levels, and (ii) habitats with fresh or slightly saline waters. We showed that these two groups of Ulva, which occupy distinct habitats, represent two separate taxa. The first group represents Ulva flexuosa subsp. pilifera (Kutzing) M.J. Wynne, which is very common and regularly encountered in fresh waters, but is equally well represented in slightly saline waters. The second is U. flexuosa subsp. paradoxa (C. Agardh) M.J. Wynne, which is less common, preferring mainly salt-wedge saline waters. We did not find both Ulva flexuosa subspecies together at any of the research sites.There were significant morphological differences between the Ulva flexuosa subspecies. U...

The possibility of using freshwater Ulva (Chlorophyta) as a bioaccumulator of metals (Co, Cr, Cu, Mn and Zn) in lake and river water was examined weekly in the summer of 2010 in three types of samples: the water, the sediment and the thalli of Ulva. Samples of freshwater Ulva were collected from two aqueous ecosystems lie 250 km away from the basin of the Baltic Sea and 53 km from each other. A flow lake located in the centre of the big city was the first water reservoir (10 sites) and second, the suburban river (6 sites). The mean metal concentrations in the Ulva tissue from the river and the lake decreased in the following order: Mn>Zn>Cr>Cu>Co and Mn>Cr>Zn> Cu>Co, respectively. Moreover, a negative and statistically significant correlation between Mn concentrations in the Ulva thalli and the river water was observed. Additionally, numerous correlations were noted between the different concentrations of metals within the Ulva thalli, in the water and in the sediment. The great concentrations of Mn and Zn and the smallest of Co were found in thalli of Ulva, irrespective of the type of the ecosystem from which samples of algal thalli originated. Freshwater Ulva populations examined in this study were clearly characterized a dozen or so times by the higher Mn and Cr accumulation than taxa from that genera coming from sea ecosystems. The calculated bioconcentration factor (BCF) confirm the high potential for freshwater Ulva to be a bioaccumulator of trace metals in freshwater ecosystems. This project was supported by funds from the Polish Ministry of Science and Higher Education; grant number N N304 013 437. The field research was funded partially by the project GDWB-07/2011. Andrzej Rybak has received a PhD fellowship from the Adam Mickiewicz University Foundation.

This paper presents the results of ultrastructural studies and ecological aspects of some phytoplankton species belonging to the groups of cyanobacteria (Planktothrix rubescens, Synechocystis aquatilis) and green algae (Desmodesmus grahneisii). Specimens were collected during summertime from the mesotrophic and stratified Lake Holzmaar (Western Germany) as planktonic forms from the pelagic zone. The highest cyanobacterium concentration was detected in the metalimnion, where the alkaline pH, low phosphorus and high nitrogen contents were recorded. P. rubescens was characterized by straight filaments up to 1000 μm long and 5.4-8 μm wide and numerous aerotopes in cells. The accompanying algae were identified by ultrastructural analysis and photographic documentation was provided. In the case of D. grahneisii, chloroplast was situated in the parietal part of cell, with one large, oval pyrenoid and, in addition, the granular and spiny cell wall was an important taxonomical criterium for the Desmodesmus genus. This is in contrast with the cyanobacterium S. aquatilis, in which a homogeneous content with visible chromatoplasma was mostly distributed throughout the cell. This algal association was stable in the epilimnion characterized by the presence of high temperature, pH values (>8), nitrate nitrogen and oxygen concentrations

The paper includes results of the first study on the accumulation of selected metals in freshwater populations of Ulva taxa at 16 sites in Poland. The thalli examined contained very high concentrations of Ca and Mg, owing to well-developed surface incrustations of carbonate. Among the heavy metals investigated, the most significant concentration in the thalli was Ni, whereas the lowest was Pb. The median concentrations of Ni and Cd in the freshwater Ulva thalli were significantly higher than those reported in the available literature for marine taxa of the same genus. Several statistically significant correlations were found when the concentrations of different metals in the thalli and the water were analysed.

We analyzed the ability of freshwater taxa of the genus Ulva (Ulvaceae, Chlorophyta) to serve as bioindicators of metal in lakes and rivers. Changes in heavy metal (Ni, Cd and Pb) and alkaline earth metal (Ca and Mg) concentrations in freshwater Ulva thalli were investigated during the period from June to August 2010. The study was conducted in two ecosystems in Western Poland, the Malta lake (10 sites) and the Nielba river (six sites). Three components were collected for each sample, including water, sediment and Ulva thalli. The average concentrations of metals in the water sample and in the macroalgae decreased in the following order: Ca > Mg > Ni > Pb > Cd. The sediment revealed a slightly altered order: Ca > Mg > Pb > Ni > Cd. Ca and Mg were found at the highest concentrations in thalli due to the presence of carbonate on its surface. Among the examined heavy metals in thalli, Ni was in the highest concentration, and Cd found in the lowest concentration. There were statistically significant correlations between the levels of metals in macroalgae, water and sediment. Freshwater populations of Ulva exhibited a greater efficiency to bioaccumulate nickel as compared to species derived from marine ecosystems.

The phytoseston flora and heterotrophic bacteria from the two intersecting rivers were studied during the intensive water flow (from October 2006 to May 2007). The physical and chemical measurements indicated that the water quality in the rivers regarding their purity, had slightly improved in the Nielba River and deteriorated in the Wełna River, at the sites behind the intersection zone. It was in the agreement with the studied phytoseston diatom communities (dominated by eutraphentic taxa). Phytoplankton during the winter months was dominated by Aulacoseira granulata. The importance of species from the genera Oscillatoria, Planktolyngbya, Tychonema, Planktothrix, Scenedesmus/Desmodesmus, Nitzschia and Fragilaria increased in spring and autumn. Heterotrophic bacteria occurred in considerably higher numbers in the Wełna River than in the Nielba River, with a significant decrease in the waters of the Wełna River behind the river-intersection. All analyses revealed that the waters in the Wełna River were more polluted with organic compounds than in the Nielba River locations.

Five small water bodies located within the agricultural region of Wielkopolska (west Poland) underwent inves- tigation. Periphyton samples were collected from various macrophyte habitats representing rush vegetation (in five water bodies), submerged aquatic plants (in three) and nymphaeids (in one): Pal˛ edzie - Ceratophyllum demersum, Potamogeton crispus, Typha latifolia; Batorowo - Phragmites australis ;P iotrowo -Potamogeton natans, Ceratophyllum submersum, Ty- pha latifolia; Tarnowo Podgorne - Typha latifolia ;D ˛ - Zannichellia palustris, Potamogeton pectinatus, Phragmites australis. The main goal of the study was to determine the composition and abundance of the periphytic communities inhabiting various types of rush and water vegetation of five water bodies located within a mid-field landscape area. Diatoms such as Achnanthidium minutissimum, Amphora ovalis, Cocconeis placentula orNavicula cincta revealed signifi- cantly higher densities in the zone of elodeids, while green algae prevailed among nymphaeids. As a result of this study it was found that the epiphytic algae were characterised by much lower diversity in respect to a specific water body, though much greater diversity was observed in its relation to the type of substratum. Two types of habitats were distinguished - the first of simple build (helophytes and nympheids) and the second containing the complicated architecture of plant stems (elodeids).

The effects of the impact of four organic compounds (ascorbic acid, biotin, glucose and sucrose) on ash, protein, fiber, fat and amino acid contents in the freshwater Aegagropila linnaei biomass were examined in 7 and 14 days of cultivations in high concentrations of tested compounds (100 mg L-1). The presence of examined organic compounds had a negligible effect on the development of algae and their biomass composition. There were no significant differences in the amino acids composition in the biomass in the presence of organic compounds compared to the test system. However, the increase in ash content was observed irrespective of the cultivation time in the case of all used organic compounds. Only slight differences in crude fat concentration were observed in the case of 7 days cultivation with ascorbic acid, biotin and sucrose, while the highest increase of ash content was observed after 14 days of supplementation with glucose. None of the compounds affected changes in amino acid content in the Aegagropila linnaei biomass. The results suggest that an environment enriched with the test organic compounds had only minimal, or at most short-term, effects on the algal biomass composition.

The paper discusses the potential applicability of the process of supercritical fluid extraction (SFE) in the production of algal extracts with the consideration of the process conditions and yields. State of the art in the research on solvent-free isolation of biologically active compounds from the biomass of algae was presented. Various aspects related with the properties of useful compounds found in cells of microalgae and macroalgae were discussed, including their potential applications as the natural components of plant protection products (biostimulants and bioregulators), dietary feed and food supplements, and pharmaceuticals. Analytical methods of determination of the natural compounds derived from algae were discussed. Algal extracts produced by SFE process enable obtaining a solvent-free concentrate of biologically active compounds; however, detailed economic analysis, as well as elaboration of products standardization procedures, is required in order to implement the products in the market.

Ulva flexuosa subsp. pilifera (Kütz.) M. J. Wynne 2005 (= Enteromorpha pilifera Kützing 1845) was previously found in Argentina, the Czech Republic, Germany, Hungary, Romania, Slovakia and Sweden, recently also in Poland. The genus Ulva was first time described as Enteromorpha. Interestingly, Enteromorpha is used nowadays as a synonym for Ulva, a development which is based on molecular data. The morphologies of both young and mature specimens were studied, and most life cycle stages could be observed. Further, the formation of calcium carbonate crystals on the surface of Ulva thalli seems to influence the arrangement of the cells. A detailed ultrastructural (TEM) analysis of cell walls is presented. The TEM reveals in great details highly complex, irregular structures with stratification lines. The project was supported by funding from the Polish Ministry of Science, grant No. NN 304 013 437 and partially funded by the project GDWB-07/ 2011. 82 2 157 163 Acta Societatis Botanicorum Poloniae

In this work, the authors examined the presence of cyanobacteria and cyanotoxins in 21 samples collected from fresh water bodies located in 5 provinces in Poland: Lublin (2), Podlasie (1), Pomerania (6), Warmia-Masuria (1) and Wielkopolska (11). In addition, to determine the general pattern of geographical distribution, frequency of cyanobacteria occurrence, and cyanotoxins production, the published data from 238 fresh water bodies in Poland were reviewed. On the basis of these collected results, we concluded that Planktothrix, Aphanizomenon, Microcystis and Dolichospermum were dominant. The general pattern in geographical distribution of the identified cyanobacterial genera was typical of other eutrophic waters in Europe. The production of cyanotoxins was revealed in 18 (86%) of the 21 samples analyzed in the present work and in 74 (75%) of the 98 total water bodies for which the presence of toxins had been examined. Among the 24 detected microcystin variants, [Asp3]MC-RR was most common. These results can be verified when more data from the less explored water bodies in the southern and eastern parts of Poland are available. The authors would like to acknowledge the European Cooperation in Science and Technology, COST Action ES 1105 "CYANOCOST- Cyanobacterial blooms and toxins in water resources: Occurrence, impacts and management" for adding value to this study through networking and knowledge sharing with European experts and researchers in the field. 42 4 358 378

The influence of physicochemical factors on the development of Ulva species with distromatic tubular morphology was studied in three streams located in Poznan, Poland. The study evaluated key environmental factors that may influence the colonisation and growth of Ulva populations in freshwater systems. In total, nine environmental parameters were included: temperature, water depth, pH, oxygen (O2), ammonium (NH4 +), nitrate (NO3 −), phosphate (PO4 3−), sodium chloride (NaCl) and total iron (Fe). Morphometric features of thalli (length and width, percentage of furcated and young thalli) and surface area of free-floating mats formed by the freshwater populations of Ulva were compared at all sites. Principal components analysis indicated the most important factors influencing Ulva development were sodium chloride concentrations and water depth. Two other key chemical factors affecting the freshwater form of Ulva were phosphate and nitrite concentrations. High concentrations of sodium chloride inhibited the development of Ulva, leading to a lower number of thalli in the Ulva mats. At the sites with stable and deeper water, the surface area of the mats was larger. Both phosphate and nitrite concentrations were positively correlated with an increase in the number of thalli in the mats and the thalli length.