For the qualitative and quantitative analyses ANABAENA BERGII OSTENF. [F. MINOR (KISSELEV) KOSSINSK.] (CYANOPROKARYOTA) – THE FIRST RECORD IN SERBIA, ITS TAXONOMIC STATUS, AND THAT OF THE GENUS ANABAENA BORY EX BORN. & FLAH

Within the framework of a detailed survey of the algal community in salt marshes of the Vojvodina Province (Northern Serbia), we rather unexpectedly found the blue-green alga Anabaena bergii ostenf. [forma minor (Kisselev) Kossinsk.] in water samples from Slatina Pond near opovo. our finding represents its first record in Serbia. the present paper gives general characteristics of this alga and of the habitat in which it was found. Based on analysis of a large number of works dealing with characteristics and the taxonomic status of the genus Anabaena, the species A. bergii, and its forma minor, it is concluded that there are numerous problems in taxonomy of the given genus, with no consensus among researchers. In light of the available data, the authors retain the name of the species A. bergii, but accept forma minor with some reserve.

Microscopic processing of algal samples was done at the Institute of Botany of the Faculty of Biology on a Zeiss AxioImager.M1 microscope using AxioVision 4.6 software.
Quantitative analysis was done according to utermöhl (1958).
the habitat in which Anabaena bergii ostenf.[formaminor (Kisselev) Kossinsk.]was found was marked on a utM map grid with cells of 10 x 10 sq.km, on which the territory of the republic of Serbia encompasses 986 squares and belongs to the 34 t utM world section.records of certain taxa of the division cyanoprokaryota on the territory of Serbia, including also data on A. bergii (forma minor) were analyzed according to Blaženčić and cvijan (1988) and cvijan and Blaženčić (1996), as well as on the basis of reviewing all works published from 1996 to date on algae occurring in Serbia and information in the database of the chair of Algology, Mycology, and lichenology of the Faculty of Biology in Belgarde.
reSultS ANd dIScuSSIoN

I. Location and general characteristics of Slatina Pond
Slatina Pond is situated in the vicinity of the village of opovo, about 30 km north of Belgrade, in the val-ley of the lower course of the tamiš river (Fig. 1). the climate of this region is temperate-continental.Precipitation during the year is unevenly distributed, with two distinct maximums (primary in June, secondary in November and december) and two minimums (primary in october, secondary in March) (Ćurčić, 1996).Winds are an important climatic factor, the most frequent one being that from the southeast.
Waters in the environs of opovo consist of underground waters of the tamiš river, river lakes, ponds, and swampy terrains.In depressions of diluvial terraces, salt marshes also occur (Ćurčić, 1996).
Slatina Pond is a natural fluvial lake located on a diluvial plain.this is a fossil riverbed showing traces of varying phases of shifting of the tamiš river course.Marsh humus occurs within arcs of the old meander of Slatina Pond, whereas the bottom is salted humus.the water level in Slatina Pond depends on the level of the tamiš river and that of phreatic waters, whose mid-depth near Slatina Pond amounts to 0.8 m (Ćurčić, 1996).For all these reasons, Slatina Pond is distinguished by an unstable water level.the banks of Slatina Pond are overgrown with reed and cattail, whereas its central part constitutes free water.

II. Characteristics of A. bergii Ostenf. [forma minor (Kisselev) Kossinsk.] and habitats in which it was recorded
Analysis of algal samples collected from the water of Slatina Pond revealed the presence of a great number of algal taxa.out of 10 taxa of the division cyanoprokaryota (the division's name is according to Komárek and Anagnostidis, 1998) found in Slatina Pond, particularly interesting and unexpected is the record of A. bergii ostenf.[forma minor (Kisselev) Kossinsk.],which is the subject of the present paper.detailed analysis of other algae from Slatina Pond will be presented in future papers.
According to Gollerbakh et al. (1953), A. bergii is found in plankton of salt waters, whereas forma minor occurs in plankton of salt waters and relict lakes.In recent literature (Komárek and Komárkova, 2006), it is stated that A. bergii ostenf.occurs in the plankton of salt lakes of the temperate eurasian zone (which is not quite correct -for details see III).We note that A. bergii, and particularly its forma minor, have been relatively rarely recorded in the world.
In view of the above, the record of A. bergii (forma minor) in Slatina Pond might be considered to be rather unexpected.However, water of the pond in its physicochemical properties (table 2) basically corresponds to characteristics of the habitat from which the taxon was originally described, as well as to properties of many habitats in which it was later found.
to be specific, as can be seen from table 2, the concentrations of sulfate, calcium, magnesium, potassium, and (especially) chloride and sodium in Slatina Pond are very high.As a consequence, values of water electro conductivity and pH are also remarkably high.
In addition, it should be noted that Slatina Pond at the time of sampling was characterized by relatively great depth (0.9 m), but also by significantly decreased water transparency (0.35 m), given that water movements caused by air currents readily swept very fine deposit upwards to the free water.Naturally, the presence of a significant number of algae in the water also contributed to decrease of water transparency, but certainly to a lesser extent than the air current.
It is necessary to mention the comparatively high oxygen content in the water of Slatina Pond, especially in the light of high water temperature.
Quantitative analysis of algae from the water of Slatina Pond showed that A. bergii (forma minor) in the plankton was represented by a relatively small number of individuals (about 1720 trichomes/l), from which it might be concluded that it developed under conditions which did not fully suit it.However, the absence of akinetes suggests the opposite conclusion.Besides, in the material collected from other plants, individuals of A. bergii (forma minor) were present in somewhat higher numbers.
It is therefore certain that physicochemical properties of the water were favorable for the development of A. bergii (forma minor), the low abundance of its individuals being conditioned instead by competition with other algae, also well adapted to the specific physicochemical conditions of their environment.
on the other hand, A. bergii (forma minor) is a multicellular, filamentous alga, so comparison of its abundance with that of the large number of unicellular algae present would not be correct.to be specific, in 18 analyzed individuals of A. bergii, the number of cells in the filament ranged between 22 and 53, the average being 40.25.
After consulting Blaženčić and cvijan (1988), cvijan and Blaženčić (1996), and all published works treating the algae of Serbia from 1996 to date, we established that Anabaena bergii ostenf.[forma minor (Kisselev) Kossinsk.] is here recorded for the first time on the territory of Serbia.
According to elenkin (1938), Anabaena bergii ostenf.is found in the plankton of salt waters and was recorded and described as early as the beginning of the 20th century in plankton of the Aral Sea (ostenfeld, 1908, according to elenkin, 1938).

Gollerbakh et al. (1953) reduced A. bergei var.
minor Kisselev to the rank of a forma under the name of A. bergii forma minor (Kisselev) Kossinsk.
However, problems regarding the taxonomic status of the genus Anabaena Bory ex Born.& Flah.are remarkably great, with the result that the taxonomic status of individual species within this genus is in many cases unclear and their classification difficult.
the extent to which the taxonomy of A. bergii is still unclear is evident from the fact that Hindák in one work considers that A. bergii var.minor Kisselev sensu Hindák is a synonym of the species A. minderi (Hindák, 1992), whereas in another he treats A. bergii var.minor Kisselev as a synonym of the species A. bergii (Hindák, 2000).
on the other hand, many authors deny existence of the genus Anabaena as a fully independent entity.thus, 20 years ago Komárek and Anagnostidis (1989) proposed including the so-called "traditional species of the genus Anabaena with apoheterocystic trichomes" in the genus Trichomus (ralfs ex Born.& Flah.)Komárek & Anagnostidis.
According to Komárek and Kováčik (1989), some Aphanizomenon and Anabaena species (including A. bergii) "belong to a group of species characterized by solitary trichomes which are narrowed towards the ends and in which elongated terminal cells are absent".thus, the position of this group within the genus Anabaena or Aphanizomenon or even as a separate genus is still open to question (Komárek and Kováčik, 1989).
It has been further suggested that Aphanizomenon ovalisporum and Anabaena bergii are morphological variants of the same cyanobacterium (Fergusson and Saint, 2000).
on the other hand, in analyzing the diversity of Aphanizomenon-like cyanobacteria, Komárek and Komárkova (2006) separate a morphotype ("morphotype of Aphanizomenon gracile") as a heterogenous group possibly encompassing some Anabaena-morphotype such as A. bergii, which they maintain lives in the plankton of salt lakes of the temperate eurasian zone (see delgado and Sánches, 2005; Wood et al., 2005;Hamed, 2008).
According to Komárek and Zapomĕlova (2007), the traditional cyanobacterial genus Anabaena Bory ex Born.& Flah.contains several groups of morphospecies that should be classified into different genera according to modern phenotypic and molecular criteria.Moreover, their separation into several clusters was confirmed by 16S rrNA sequencing.According to the cited authors, the generic name Anabaena must also be maintained for benthic species without gas vesicles.on the other hand, the planktonic types fall into several subclusters.However, it should be pointed out that A. bergii is a planktonic species and that Komárek and Zapomĕlova (2007) did not analyze its taxonomic status.coNcluSIoNS A detailed survey of salt marshes in the Vojvodina Province (Northern Serbia) was carried out during 2003, 2004, and 2006.one of them was Slatina Pond near opovo, from which samples were collected on three occasions, on one occasion in each research year in March, April, and July, respectively.
For the qualitative and quantitative analyses of algae and physicochemical analyses of water of interest to us currently, samples were collected from Slatina Pond on 18 July 2006.
Analysis of algal samples collected from the water of Slatina Pond revealed the presence of a great number of algal taxa.out of 10 taxa of the division cyanoprokaryota found in Slatina Pond, particularly interesting and unexpected is the record of Anabaena bergii ostenf.[forma minor (Kisselev) Kossinsk.],its first record in Serbia.this record was rather unexpected in light of data on the distribution of A. bergii forma minor worldwide, as well as characteristics of the habitats from which it was originally described and those where it was found later.detailed analysis of physicochemical properties of the water in which this alga developed revealed high concentrations of sulfate, calcium, magnesium, potassium, and (particularly) chloride and sodium.As a consequence, water electro-conductivity and pH values were very high.Such physicochemical properties of the water in which this alga was found corresponded more or less considerably to those of water of the habitat from which the form was originally described and in which it was found later.
Based on analysis of a great number of works dealing with the characteristics and taxonomic status of the genus Anabaena Bory ex Born.& Flah., the species A. bergii (Kisselev) Kossinsk., and its forma minor (Kisselev) Kossinsk., it is concluded that there are numerous problems relating to taxonomy of the entire genus and no clear consensus among researchers about it.In addition, at the level of the central european algal flora (see Süβwasserflora von Mitteleuropa), the revision of algae of the division cyanoprokaryota (to which Anabaena belongs) has not been done as yet.
of algae and physicochemical analyses of water of interest to us currently, samples were collected from Slatina Pond on 18 July 2006.Water temperature (by mercury thermometer, accuracy of 0.1 o c) and transparency (by Seccidisc) were measured at the time of sampling.determination of other physicochemical parameters was done at the Institute of Public Health of Serbia in Belgrade.Samples of phytoplankton for qualitative analyses were collected by filtering water through a plankton net (mesh size of 25 µm).Samples of epiphytes were collected from Phragmites australis (cav.)trin.& Steud.(= Ph. communis trin.) and Typha latifolia l. by scraping from the plants or together with parts of the plants themselves.

Table 2 .
Physicochemical properties of the water of Slatina Pond near Opovo.