Periphytic and planktonic algae records from the upper Paraná river fl oodplain , Brazil : an update

1. Universidade Federal do Pará, Programa de Pós-graduação em Ecologia, Rua Augusto Corrêa, 1, Campus Guamá, 66075-110 Belém, PA, Brasil 2. Universidade Estadual de Maringá, Departamento de Biologia, Av. Colombo, 5790, 87020-900 Maringá, PR, Brasil 3. Universidade Estadual de Maringá, Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais, Av. Colombo, 5790, 87020-900 Maringá, PR, Brasil 4. Corresponding author: dunck.barbara@gmail.com ABSTRACT (Periphytic and planktonic algae records from the upper Paraná river fl oodplain, Brazil: an update). The upper Paraná river fl oodplain is a strategic area for the Brazilian biological and environmental patrimony and contains several conservation units. We aimed to record the occurrence and the geographic distribution of microalgae in this fl oodplain during 30 years of research carried out by the Center for Research in Limnology, Ichthyology and Aquaculture State University of Maringá. We consulted 80 publications (national and international journals and books published from 1986 to 2016). We considered only published works that referenced algae at the generic and infrageneric levels. The results indicated 938 species of algae (562 periphytic, 482 planktonic), which 103 co-occur in the two habitats. Cosmarium was the richest genera for periphyton and Traquelomonas for phytoplankton. This study increased the knowledge of microalgae biodiversity in Brazil and provided data for future ecological and biogeographic studies.


Introduction
Regarding the fl ora of aquatic organisms, algae are important contributors to overall primary productivity.They comprise a polyphyletic grouping of both prokaryotic and eukaryotic producers (autotrophic or heterotrophic protists), important on the trophic webs to act on primary productivity and as food for various herbivores.They can be defined as single-celled organisms, which do not have reproductive organs involved by sterile cell layers, with a wide variety of forms, functions and strategies (Bicudo & Menezes 2010).
Brazil has an extensive hydrographic network, rich in natural rivers, lagoons and canals, and yet, proportionally, there is scarce knowledge about the biodiversity and the dynamics of microalgae (Agostinho et al. 2004, Menezes et al. 2015).The continental dimensions of this country, the high diversity, lack of laboratory facilities and the high logistic cost make the records of occurrence restricted to the geographic areas of activity of the few research groups (Bicudo & Menezes 2010, Grieneisen et al. 2014, Menezes et al. 2015).Until now, the species distribution among the Brazilian states and the geopolitical regions are considered heterogeneous with predominance in southeast and south regions (Menezes et al. 2015).
Some surveys have been carried out to demonstrate the documented flora of these microorganisms in Brazil.Currently, Menezes et al. (2015) have compiled data to update the list of algae and cyanobacteria from Brazil previously published by Bicudo & Menezes (2010) in the Catalog of Plants and Fungi from Brazil (Forzza et al. 2010).This update showed that there are 4,747 species registered in different environments and biomes in Brazil.However, the same update also indicated that this estimate is far from the actual algal diversity present in Brazil, due to the extensive geographical area represented by this country and the gaps in scientific research.
The Brazilian southern region houses one of the main floodplains of the country, the upper Paraná river floodplain (54º20'-53º30'/24º00 '-22º50').It is located on the right margin of the last stretch of this river that is free of reservoirs in the Brazilian territory, located between the reservoirs of Porto Primavera and Itaipu.This region has a recognized strategic area for the Brazilian biological and environmental patrimony, with two federal conservation units (Ilha Grande National Park and APA of the Islands and Várzeas of the Paraná River) and one state park (Ivinheima State Park).The upper Paraná river floodplain was incorporated into the Biosphere Reserve of the Atlantic Forest-t MAB/UNESCO (Agostinho et al. 2004, Takemoto & Lizama 2010).
Studies in this region have been developed since 1986 by researchers from Nupélia (Center for Research in Limnology, Ichthyology and Aquaculture -State University of Maringá), who are responsible for one of the most important databases on Freshwater biology and ecology in Latin America.Plenty of information about the characteristics of the environment, fauna and flora is contained in scientific papers, technical reports (available at http://www.peld.uem.br/), and papers of diffusion, theses and dissertations of the Program of Postgraduate in Ecology of Continental Aquatic Environments of the State University of Maringá.Some researches have indicated that the freshwater microalgae of this area represent 8% of the total microalgae found in Brazilian territory (Train & Rodrigues 2004, Agostinho et al. 2004).Indeed, despite the number of already developed taxonomic and ecological, observational and/or experimental studies, there are still background gaps in the biodiversity of microalgae in this area.In this way, this work aimed to record and disseminate information of the microalgae (periphytic and planktonic) occurring in the upper Paraná river floodplain based on scientific papers published since 1986.
Review of articles -To create a catalog of species and respective articles in which they are cited we use papers and books published nationally and internationally.We consult the basis of Scielo, Web of Science, Lattes platform, the library of the Program  As the goal was to look for scientific papers published since 1986, we noted that the first published works date of the year 1994.Thus, we use data from 1994 to 2016.We considered only works that referenced algae at the generic and infrageneric level (excluding studies referring only to large groups or algal biomass).Species richness was considered as the sum of specific and infraspecific taxonomic units (even if cited for more than one environment) recorded in the floodplain.We consider also the number of species registers counting the number of studies in which they are registered.
The species are presented and organized by classes, both species and classes in alphabetical order.The classification system adopted was Round (1971) for all algae classes.The species in the catalog are presented with the respective articles in which they were cited.We present the updated species name based on Algaebase (http://www.algaebase.org/)including as synonymous (=) the species name cited in each work we consulted.We also included species cited as conferatum, and the variety of species when were cited in the papers.

Results and Discussion
From the 80 national and international papers published in scientific journals and book chapters (taxonomic studies, ecological, experimental and observational studies) published from 1994 to 2016, we used 41 because lots of them only referring to large algae groups or algal biomass.These works encompassed 28 papers of periphytic algae and 13 of planktonic algae.The scientific published studies used are shown in table 1.

Conclusion
This study indicated that, since 1994 to 2016, 80 publications of some aspect of algae of the upper Paraná river floodplain were published.From these, 41 referenced algae at the generic and infrageneric level, and the compilation of them indicated 938 species, which constitutes an expressive microalgae richness for this study area.In the total, the Chlorophyceae class was the richest one followed by Zygnemaphyceae, but in the periphytic habitat Bacillariophyceae was the richest class, and in phytoplankton Chlorophyceae class.Some of these species may not be included in the Brazilian list of algae (which now has something around 4,747 species recorded so far) and now can be included.
This study contributed to the knowledge of the Brazilian microalgae biodiversity and provided data for future ecological and biogeographic studies.
This study also demonstrated the importance of long-term studies (PELD-CNPq site 6) in the survey of biodiversity.We suggest that these compilations be made also using research reports to increase information about the Brazilian flora and fauna, and improve the knowledge of Brazilian biodiversity.

Figure 1 .
Figure 1.The upper Paraná River floodplain and environments sampled over the years until 2006.

Figure 2 .
Figure 2. Proportion among taxonomic classes in the upper Paraná River floodplain.
of Postgraduate in Ecology of Continental Aquatic Environments of the State University of Maringá and Nupelia, and teachers' personal collection to do this survey.

Table 2 .
Occurrence of periphytic and planktonic algae in the upper Paraná river floodplain and respective citations.The updated species name was based on Algaebase; equal symbol (=) indicates the species synonymous (heterotypic, taxonomic synonym) cited in the consulted work, and (≡) indicates the homotypic synonym (if cited in the work consulted); numerals (1 to 41) indicate the citation reference and habitat (1-28: periphytic habitat; 29-41: planktonic habitat) of the list in Table1; asterisk (*) indicates the species common to both habitats.