The
In Europe, only 54 species have been reported so far (Krammer & Lange-Bertalot 1988). In recent years, new species of
In the Acadia National Park, Maine, the USA, two very interesting species of
Diatoms of the
Due to the unique nature of
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: 51o20’58.18’’, E: 19o52’52.04’’ PUWG (State Geodetic Coordinate System) 1992] (Fig. 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].
Physical and chemical characteristics of water in the Pilica River
Parameter
Unit
03-10-2005
07-11-2005
05-12-2005
03-07-2006
01-08-2006
04-09-2006
02-10-2006
04-12-2006
09-07-2007
07-08-2007
10-09-2007
Water temperature
°C
13.7
7.5
3.7
19.4
20.4
17.3
15.3
5.4
20.6
20.8
15.0
pH
-
7.7
7.7
8.0
8.0
8.0
7.8
7.6
8.1
8.1
8.1
8.1
Dissolved oxygen
mg O2 l-1
9.6
10.9
12.0
8.2
7.9
8.9
9.5
10.9
9.3
8.76
8.89
BOD5
mg O2 l-1
3.4
4.1
3.6
2.1
5.1
2.0
2.7
2.4
3.1
5.6
1.9
COD-Cr
mg O2 l-1
12.0
19.7
16.0
36.0
22.0
16.9
36
12.8
23.0
16.5
16.0
Kjeldahl nitrogen
mg N l-1
0.67
0.45
0.46
0.71
0.64
0.35
0.28
0.63
0.79
0.24
0.55
Nitrates
mg NO3 l-1
3.45
4.15
5.30
5.30
1.90
3.71
4.42
7.52
2.16
3.05
0.66
Nitrites
mg NO2 l-1
0.013
0.016
0.036
0.03
0.03
0.026
0.016
0.033
0.016
0.013
0.01
Total nitrogen
mg N l-1
1.5
1.4
1.7
1.9
1.1
1.2
1.3
2.3
1.3
0.93
1.2
Phosphates
mg PO4 l-1
0.09
0.08
0.07
0.11
0.12
0.13
0.15
0.09
0.12
0.12
0.11
Total phosphorus
mg P l-1
0.03
0.05
0.05
0.08
0.05
0.07
0.06
0.07
0.13
0.05
0.05
Conductivity
µS cm-1
366.0
358.0
391.0
369.0
360.0
348.0
366.0
361.0
353.0
348.0
335.0
Chlorides
mg Cl l-1
9.8
11.2
11.8
12.2
10.6
12.1
12.5
11.7
10.3
12.1
10.4
Bacillariophyta
Bacillariophytina Medlin & Kaczmarska (2004)
Bacillariophyceae Haeckel 1878 (emended diagnosis Medlin & Kaczmarska 2004)
Surirellales Round, Crawford & Mann (1990)
Surirellaceae Kützing (1844)
Measurements of 100 valves of
Under LM and SEM, frustules were rectangular in girdle view with alar wings. Both valves in surface views were elongated, narrow, moderately concave in the central area, which was becoming more visiblein the head and foot poles. Valves were isopolar, panduriform in marginal and surface view (Fig. 3, photo 1), with a clear stenosis in the central part of the cell and with four equidistant, expanded, flexed alae. In the surface view, apices were rounded with a central notch; alae were expanded backward, panduriform, strongly carinated; plicae (canaliculi) were transverse, wide and semi-cylindrical, widening toward the carinae. Carinae (points of flexure) are sinuously constricted in the middle and rounded toward the truncated apices (Donkin 1869) (Fig. 4).
A narrow-lanceolate hyaline axial area was present in the center of the valve, along the apical axis (Fig. 3, photo 1). Porcae or transapical undulations were usually slightly alternately facing each other on either side of the apical axis. Porcae or transapical undulations were nearly regularly spaced, 20-25 in 100 μm.
The length of valves was in the range of 74-110 μm, the width ranged from 20 to 30 μm, the medium length of measured valves was 86.4 μm and the medium width was 24.3 μm (Fig. 3). According to the study by Krammer and Lange-Bertalot (1988), the length of
The panduriform outline of the species, in every aspect in which the frustule can be viewed, together with the notched apices of the valves, immediately distinguishes it from every other member of the genus, making it impossible to be misidentified.
A total of 242 diatom taxa were identified during the research in 23 microbenthic samples collected from the Pilica River. The following diatom taxa were dominant at this sampling site:
The species occurs mainly in European oligotrophic waters of low electrolyte content. The Pilica River at the Sulejów sampling site,
where the species has been identified, is classified as an eutrophic river with moderate ecological status (water quality class III according to the regulation 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. No. 258, item 1549 of 2011). The conditions of the river at the sampling site are relatively natural. The species
The epitype is designated on slide 143/33, X1/37, X7/12 from the Hustedt Collection, BRM (Fig. 3).
Considering the frequency of occurrence of species from the