Surirella barrowcliffia Donkin 1869 (Bacillariophyta, Surirellaceae): the first observation of the diatom in Poland

The Surirella genus (Turpin 1828: 362, 363) is considered to be one of the oldest ones. The name “Surirelle” appeared for the first time in a general diatomological description by Turpin (1828: 362: 363) as Surirella striatula (Turpin 1828: 363, pl. 15, 1-8). The genus Surirella includes over 630 taxa (species, varieties and forms) (Fourtanier & Kociołek 2011; Guiry & Guiry 2015).

In Europe, only 54 species have been reported so far (Krammer & Lange-Bertalot 1988). In recent years, new species of Surirella have been described mainly from equatorial regions such as Indonesia (Bramburger et al. 2006; 11 species) and Africa (Metzeltin & Lange-Beltalot 2002; Cocquyt & Jahn 2005; 2007a,b; 6 species). In North America, Surirella is a very rare genus with only six species – Surirella acredula, S. adumbratus, S. alicula, S. barca, S. stalagma, S. stiri and one variety – S. striatula var. spinifera described by Hohn and Hellerman (1963, 1966). In the next 10 years, Lowe (1973) described two more species from Iowa: Surirella iowensis Lowe and S. stoermerii Lowe (Lowe 1973). Only one new species (Surirella lacrimula) has been recently added to this list from Virginia, the USA (Vesela & Potapova 2014).

In the Acadia National Park, Maine, the USA, two very interesting species of Surirella were found. At first they seemed to be new to science, but careful examination under light and scanning electron microscopes revealed that these were extremely rare species (Surirella cruciata and S. terryi Terry) recorded more than 100 years ago (Schmidt et al. 1874-1959; Terry 1907), which have not been reported ever since.

Diatoms of the Surirella Turpin genus can be found in all climate zones on all continents. Taxa from this genus occur in all marine, brackish and freshwater environments (Van Heurck 1880; Cleve-Euler et al. 1952; Krammer & Lange-Bertalot 1988; Hartley et al. 1996).

Due to the unique nature of Surirella barrowcliffia and the fact that it is one of the rarest species, the main objective of this paper was to present the first observation of the diatom in Poland.

The Pilica River is located in Central Poland in the Łódź Province (Fig. 1). It is 342 km long and is the longest tributary of the Vistula. The sources of the Pilica are located in the Kraków-Czestochowa Upland, close to the village of Wola Kącikowa. The Pilica flows into the Vistula at 457 km upriver, near the village of Potycz. The catchment area of the Pilica is over 9245 km². The research was conducted at one selected sampling site – Sulejów [N: 51^o20’58.18’’, E: 19^o52’52.04’’ PUWG (State Geodetic Coordinate System) 1992] (Fig. 2).

Figure 1

Figure 2

Samples were collected at the selected sampling site once a month for a period of 24 months from October 2005 to September 2007. Diatom samples were collected from benthic sediments using a single volume pipette (25 cm³) and a rubber bulb. The collected material was poured into opaque bottles of 40 ml each. Samples were preserved in 4% formalin. Then, the collected samples were subjected to chemical reactions (mixture of chromic and sulfuric acids in the ratio of 1:2) to erase any organic contamination and to remove the cell contents so that the frustules of diatoms were empty. Next, permanent slides were prepared using a few drops of a washed sample and synthetic mounting medium Naphrax of refractive index 1.65. Diatom taxa from permanent slides were identified following the study by Krammer and Lange-Bertalot (1988). A light microscope (NIKON Eclipse 50i) with Plan 100×/1.25 immersion lens and 10x ocular lens was used to identify diatoms in the collected material. Scanning photos were made using a SEM microscope EVO 50. The SEM microscope allows you to observe all details of diatom valves that are needed for correct identification. To use the scanning electron microscope, a drop of a thoroughly washed sample was placed onto a cover slip and left to dry. The dry cover slip was then attached to a metal stub. A thin gold or gold/palladium coating was applied to the cover slip and specimen by sputtering or by evaporation under vacuum. This process is essential to ensure a good electrical contact between the stub itself and a thin metal coating. The gold film on the cover slip provides greater contrast and sharpness of photos (Round et al. 1990).

Analyses of physicochemical parameters were conducted by a laboratory of the Provincial Environmental Protection Inspectorate in the city of Łódź. The water quality was assessed on the basis of 13 parameters: water temperature, pH, BOD5, COD-Cr, dissolved oxygen, Kjeldahl nitrogen, total nitrogen, nitrates, nitrites, total phosphorus, phosphates, conductivity and chlorides (Table 1). The assessment of the physicochemical parameters was conducted in accordance with the regulations of the Minister of the Environment of 9 November 2011 on the classification of the ecological status, ecological potential and chemical status of surface water bodies [Dz.U. (Journal of Laws) No. 258, item 1549 of 2011].

Table 1

Physical and chemical characteristics of water in the Pilica River

Considering the frequency of occurrence of species from the Surirella genus in Polish freshwaters, it should be assumed that they can be found in almost all kinds of aquatic ecosystems such as springs, rivers, lakes and reservoirs (Kadłubowska et al. 1981; Wojtal et al. 2005; Żelazna-Wieczorek 2011; Noga et al. 2013; Szczepocka & Rakowska 2015), both in natural and eutrophic ecosystems (Picińska- Fałtynowicz 2007; Maciejczak & Czerwik-Marcinkowska 2010; Dembowska 2014). A large number of other Surirella species are also present in the Pilica River, such as: Surirella biseriata, S. tugrida, S. ovalis, S. robusta (Kadłubowska 1964a,b,c; Kalinowska-Kucharska & Ligowski 1976). One of the most interesting taxa is Surirella barrowcliffia Donkin 1869, which so far has never been reported from Poland. From the information available in the world’s algological databases, such as Algaterra and AlgaeBase, it appears that Surirella barrowcliffia has already been reported from England (Whitton et al. 2003) (freshwater of the Coquet River in Northumberland, England, in 1869 by Donkin), in the Crapina-Jijila lake complex in Romania (Caraus 2012), France (Amossé 1932) as well as in Finland (Tynni 1980) and in northern Germany, near Bremen in the Weser and the Kleine Wumme rivers (notes by Hustedt 1910; 1955; 1956 from the Hustedt Collection, BRM; Hustedt 1957; Ludwig & Schnittler 1996). The species has also been found in the Baltic Sea region, but it was identified as a fossil species (Krammer, Lange-Bertalot 1988). According to the identification key by Krammer and Lange-Bertalot (1988), S. barrowcliffia prefers oligotrophic waters with low levels of electrolytes. The Pilica River, in which this species has been identified, is classified as an eutrophic river with moderate ecological status (water quality class III). However, at some distance from the sampling site, there is a limestone mine that may affect the pH of water at the site. The water there is slightly alkaline, and consequently, the conditions might be more favorable for the occurrence and reproduction of S. barrowcliffia.