Distribution, morphology and ecological niche ofBatrachospermumandSheathiaspecies (Batrachospermales, Rhodophyta) in thefontaniliof the Po plain (northern Italy)

Abstract

Twenty-three freshwater springs of the Po plain (northern Italy) were surveyed and visited multiple times during 2011-2013 to assess water quality and algal taxa present. Despite poor water conditions of this human-altered floodplain, a relatively high number of taxa referable to the freshwater red algae, Batrachospermum and Sheathia, were observed. The identity of specimens collected was based on morphology and confirmed with sequence data. The specimens belonged to Sheathia arcuata, S. boryana, Batrachospermum atrum, B. gelatinosum and B. gelatinosum f. spermatoinvolucrum. This is the first report of B. gelatinosum f. spermatoinvolucrum outside North America. Niche analysis revealed a marked difference in the physical and chemical preferences of the freshwater red algae recorded. The occurrence of S. boryana was limited to relatively low nitrate and higher oxygen concentrations. Conversely, the spatial distribution of the other four taxa indicated that they were able to tolerate high concentrations of nitrate (up to 53.6 mg l -1 ) and low rates of dissolved oxygen saturation (as low as 3%). All the specimens of B. gelatinosum collected had few to many trichogynes deformed by a basal protuberance or knob, a structure previously unobserved in this species. No other taxa showed any deformities. The ecological analyses confirmed the existence of a relationship between the environmental conditions of the springs and the occurrence of knobs.

Diversity of Batrachospermales (Rhodophyta) in the Iberian Peninsula

“…Despite the wide geographic distribution of B. gelatinosum in the Northern Hemisphere (Sheath & Sherwood 2002;House et al 2010;Eloranta et al 2011;, there are few data on the physical and chemical characteristics of the streams for which there are molecular data for specimens. Three recent studies of streams in France and Italy report B. gelatinosum from a wide range of stream parameters: specific conductance (110-825 µS.cm -1 ), pH (6.5-8.4), and temperature (9-26 °C), similar to the current and previous studies (Ceschi et al 2013;Chiasson et al 2014;Abdelahad et al 2015). Sheath & Vis (2015) also confirm the broader environmental tolerance of B. gelatinosum in North America.…”

“…The Iberian streams with S. confusa share common ecology with the populations reported in France (Chiasson et al 2014). In contrast, the environmental conditions in the Iberian Peninsula streams with S. arcuata extend the range in environmental conditions for temperature, pH and conductivity from those previously reported for France and Italy (Chiasson et al 2014;Abdelahad et al 2015).…”

“…The species Sheathia boryana, S. confusa and S. arcuata are widespread in Europe (Vis et al 2010;Eloranta et al 2011;Chiasson et al 2014;Salomaki et al 2014;Abdelahad et al 2015). A study in Italy reported S. boryana from streams with similar parameters to those of the Iberian streams: specific conductance (487-597 µS.cm -1 ), pH (7.2-7.3), and temperature (15 °C) (Abdelahad et al 2015). The Iberian streams with S. confusa share common ecology with the populations reported in France (Chiasson et al 2014).…”

Fragmentation and groundwater supply as major drivers of algal and plant diversity and relative cover dynamics along a highly modified lowland river

“…However, what appears to be important is not so much the concentration of a single key nutrient as the stoichiometric imbalance between different nutrients. When Abdelahad et al (2015) detected the widespread occurrence of red Table A.1 for site numbers and specifications).…”

Revision of sectionSetaceaof the genusBatrachospermum(Batrachospermales, Rhodophyta) with emphasis on specimens from Brazil

“…Only two species have been included in the phylogenetic analyses so far: three sequences of Batrachospermum atrum from Europe (UK and Italy, Vis et al 1998;Entwisle et al 2009;Abdelahad et al 2015) and Australasia (Western Australia, Vis & Entwisle 2000;Entwisle et al 2004;Entwisle et al 2009) and one sequence of Batrachospermum puiggarianum from South America (Brazil, Entwisle et al 2009). The phylogenetic relationships among species in section Setacea, as well as between Setacea and other sections of Batrachospermum, are poorly understood because of the limited number of sequences available.…”