Agata Z. Wojtal

Achnanthidium minutissimum (Bacillariophyta) valve deformities as indicators of metal enrichment in diverse widely-distributed freshwater habitats

In the presence of different environmental stressors, diatoms can produce frustules presenting different types of deformities. Metals and trace elements are among the most common causes of these teratological forms. Metal enrichment in water bodies can be attributed to the geological setting of the area or to pollution. The widespread benthic diatom Achnanthidium minutissimum (ADMI) is one of the most metal-tolerant species. In the present study, ADMI teratologies were defined from samples taken from eight very diverse, widely-distributed inland-water habitats: streams affected by active and abandoned mining areas, a metal-contaminated stream, a spring in an old chalcopyrite mine, a mineral-water fountain, and a sediment core taken from a lake affected by metal contamination in the past. Deformed frustules of ADMI were characterised mainly by one (sometimes two) more or less bent off ending, conferring to the specimens a cymbelloid outline (cymbelliclinum-like teratology, CLT). Marked teratologies were distinguished from slight deformities. Hydrochemical analyses, including metals and trace elements, were carried out and enrichment factors (EF) relative to average crustal composition were calculated. To improve our knowledge on the potential of different metals and trace elements to trigger the occurrence of ADMI CLT, we carefully selected 15 springs out of 110 (CRENODAT dataset) where both ADMI and above-average metal or metalloid concentrations occurred, and re-analysed these samples. The results from the eight widely-distributed core sites as well as from the 15 selected CRENODAT springs led to the hypothesis that two metals (copper and zinc) and a metalloid (antimony) were the most likely triggers of ADMI CLT formation. From a quantitative point of view, it is worth noting that the lowest concentrations triggering ADMI CLT can be fairly low, particularly in the case of copper contamination. The antimony-rich site was characterised by a marked-teratology variant where both ends of ADMI were bent off.

The Achnanthidium minutissimum complex (Bacillariophyceae) in southern Poland

Representatives of the Achnanthidium minutissimum (Kutz.) Czarn. complex are common and widespread diatoms in Poland. The following species were included in this study: Achnanthidium affine (Grunow) Czarn., A. caledonicum (LanGe-Bert.) LanGeBert., A. eutrophilum (LanGe-Bert.) LanGe-Bert., A. exile (Kutz.) HeiB., A. jackii raBenH., A. lineare w. Sm., and A. minutissimum. Two additional species are here formally described, namely Achnanthidium polonicum Van de VijVer, wojtaL, e. moraLeS et eCtor and A. acsiae wojtaL, e. moraLeS, Van de VijVer et eCtor. Information for an additional taxon is presented here, but it has been left unidentified until a larger population is found. Results of morphological analyses performed with light and scanning electron microscopy on this group of diatoms inhabiting springs, streams, rivers and lakes in southern Poland are illustrated and briefly discussed. Distribution of Achnanthidium caledonicum, A. eutrophilum, A. exile, A. lineare and A. minutissimum in waters of southern Poland corresponds well with literature reports of their autecology.

KOBAYASIELLA SPECIES OF THE CARPATHIAN REGION: MORPHOLOGY, TAXONOMY AND DESCRIPTION OF K. TINTINNUS SPEC. NOV.

The representatives of Kobayasiella Lange-Bertalot are characteristic of acidic and oligotrophic habitats. Detailed morphological observations using light (LM) and scanning electron (SEM) microscopy were performed on Carpathian populations of six species of the genus. The closely related species can easily be confused mainly due to their fine striation, but they show good distinguishing features in SEM. A comparison of the main features of the six species studied was presented, including central area, the shape of the raphe terminal fissure, the form of the kink on the raphe—which is the most important diagnostic criterion of Kobayasiella genus. In addition, the nomenclature and taxonomy of some European finely striated diatoms formerly belonging to the Navicula subtilissima group was reviewed. Kobayasiella tintinnus Buczkó, Wojtal & R. Jahn was described here as a new species from Lake Saint Anna (Romania). In order to confirm validity of Kobayasiella tintinnus sp. nov. and to provide the perfect separation from its sister species (K. micropunctata and K. parasubtilissima) continuous morphometric characters were analysed by Linear Discriminant Analysis.

A new Kobayasiella species (Bacillariophyceae) from Lake Saint Anna's sub-recent deposits in the Eastern Carpathian Mountains, Europe

A new species, Kobayasiella elongata Buczko & Wojtal, is described from Holocene sediments of Lake Saint Anna, situated in the Eastern Carpathians, Romania. Valve shape and dimensions clearly separate this species from others in the genus Kobayasiella Lange-Bertalot.

Epilithic diatom assemblages on stones of different size

Diatoms (Bacillariophyceae) are one of the most common algae in freshwater environments. They play an important role in waterbodies as producers of organic matter. Additionally, oxygen-producing diatoms have been used in the assessment of water quality for almost 100 years. Over the years new methodologies of sampling and examining diatoms have been developed (RoUNo 1993, KELLY et al. 1998, PRYGIEL et al. 1999). As a result, numero us lists and/or databases of ecological spectra for diatoms have been compiled on local and regional scales (DENYS 1991, VANDAMetal.I994,HoFMANN 1994, WATANABE & ASAI 1999), and a few diatom indices for monitoring water properties have been proposed (DESCY 1979, COSTE in CEMAGREF 1982. KI-LLY & WHITTON 1995). Assessment of water quality of lakes or large rivers most often is based on planktonic samples, whereas in watercourses epilithic diatom associations are recommended (ROUND 1991, 1993) an d usually used (ROUND 1993, PRYGIEL et al. 1999, WAIAMBE & AsAI 1999). Despite extensive literature on epilithic diatom-based monitoring studies, more precise data on the structure of diatom associations in discrete habitats are still required, and sampling techniques need to be improved and standardized. The purpose ofthe present investigation was to compare thc structure of diatom assemblages occurring on stones of different size. Diatom indices such as Trophic Diatom lndex, Index of Pollution Sensitivity and pcrcent o f Pollution Taxa were calculated for this comparison.