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The paper presents the first record of a Chara connivens (Characeae) stand from Fuerteventura (Canary Islands, Spain). The species was previously recorded only on Tenerife and Lanzarote, mostly in marine and artificial habitats. Physicochemical parameters of water and morphological features of the thalli and plant community were analyzed. General habitat requirements of C. connivens populations located in Europe, North Africa, and South-West Asia were reviewed. The newly described stand was located in a natural rock crevice that was part of a riverbed in El Barranco de las Peñitas (Penitas Canyon). This habitat was unshaded and filled with brackish water. C. connivens co-occurred with Cladophora glomerata and Ruppia maritima. Our report on the presence of C. connivens in the Spanish territory of the Atlantic Ocean is the first in almost 40 years. The distribution of C. connivens and its plant associations on the Canary Archipelago are poorly explored, which is why this topic requires further research. [ABSTRACT FROM AUTHOR]

Salinity is one of the main determinants of species diversity in macroalgae. This study analyzes the occurrence of 16 species of the genus Ulva (Ulvaceae, Chlorophyta) in the salinity gradient. Ulva populations originated mainly from shores and estuaries with a minor number occurring in ocean lagoons, coastal lakes, canals and rivers. Ulva species were found in waters where salinity ranged from <0.5 to 49 PSU. Most species were most commonly found in euhaline waters. It was observed that Ulva species with tubular thalli were present in a very wide range of saline waters (from fresh to hyperhaline waters). Ulva species with leaf-shaped thalli, however, were encountered chiefly in euhaline waters while being least often present in hyperhaline waters. It has been shown that the morphotype of the thallus (leaf-shaped or tubular) is correlated with water salinity levels. Ulva species with leaf-shaped thalli are not found in fresh (< 0.5 PSU) and poorly saline (<10 PSU) waters, whereas tubular species are recorded in freshwater, brackish, and marine ecosystems (from 0 to 39 PSU). [ABSTRACT FROM AUTHOR]

SUMMARY Cosmopolitan species of the genus Ulva (Ulvaceae; Chlorophyta) that populate the littoral zone of marine habitats constitute a staple diet for a variety of organisms, particularly snails, shellfish, polychaetes, and birds. Occurrence of Ulva species (e.g., U. flexuosa and U . prolifera) has also been observed in freshwater inland ecosystems that have no contact with saline water. However, the influence of the development of macroalgal mats of Ulva on indigenous organisms in limnic ecosystems has not been established. This study investigates the trophic relationships between Ulva flexuosa and one species of snail from freshwater habitats in central Europe. During the summer, the great pond snail ( Lymnaea stagnalis) consumed Ulva as a source of nutrition even when other algae and plants were available. Lymnaea stagnalis consumed an average of 100 mg of Ulva thalli per day. This level of biomass exceeded the consumption of an alternative food source, the shoots of Elodea canadensis. Ulva thalli are more actively consumed by great pond snails than Elodea shoots, and this is expressed in terms of the differences of biomass consumption. It was also observed that the interior of the monostromatic tubular thalli of Ulva flexuosa serves as a protective shelter for juvenile great pond snails. [ABSTRACT FROM AUTHOR]

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 (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

• Use of U. pilifera as an indicator is compatible with the WFD guidelines. • Freshwater U. pilifera occurs in eutrophic ponds. • U. pilifera can be easily identified even by non-expert. • U. pilifera can be used as trophic indicator for pond systems. • U. pilifera should be included into pond monitoring protocols. Mass occurrence of green algae of the genus Ulva in the form of algal blooms (known as "green tides") is often associated with high concentrations of biogens in the water. Therefore, Ulva species are most often used in monitoring seawater trophy and far less frequently freshwater trophy. In Europe, the biomonitoring of river ecosystems is based on aquatic plants. According to the River Macrophyte Index (RMI), river populations of Ulva macroalgae (only tubular Enteromorpha -like Ulva) are considered good indicators for eutrophic waters. This paper analyses the legitimacy of using U. pilifera as a trophy indicator in the case of ponds. It has been noted that freshwater populations of U. pilifera are much more common in lakes, dammed reservoirs, or ponds than in rivers. In this study, analysed populations of U. pilifera originated from 14 ponds located in central Poland. Data analysis relied on the Carlson Trophic State Index (CTSI), which was compared with other known trophic indices. According to CTSI values, U. pilifera was most common in eutrophic ponds, where the mean concentrations of ammonium nitrogen, nitrates, total phosphorus, and chlorophyll a reached 581, 241, 212, and 20 µg·L−1, respectively. The results indicate that U. pilifera can be considered a bioindicator for eutrophic waters (50–70 of CTSI). It would therefore be appropriate to introduce U. pilifera as part of biomonitoring conducted in small bodies of water. Major arguments in favour of practical application of U. pilifera are: (i) it is a large macroalga, the thalli of which can reach a length of > 1.0 m, (ii) it is an easy-to-identify species; even by non-experts (it is characterized by a distinctive tubular shape of the thallus), and (iii) it occurs in bulk in conditions of eutrophy, creating an easily observable bloom. [ABSTRACT FROM AUTHOR]