Research Article |
Corresponding author: Mateusz Rybak ( matrybak91@gmail.com ) Academic editor: Kalina Manoylov
© 2023 Mateusz Rybak, Paweł Czarnota, Teresa Noga.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Rybak M, Czarnota P, Noga T (2023) Study of terrestrial diatoms in corticolous assemblages from deciduous trees in Central Europe with descriptions of two new Luticola D.G.Mann taxa. PhytoKeys 221: 1-40. https://doi.org/10.3897/phytokeys.221.95248
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Although many studies have examined the algae associated with various habitats in tree trunks, the diatoms in these environments are still poorly studied. Studies of corticolous algae mainly focus on green algae and cyanobacteria, which are usually immediately visible, while diatoms are mostly overlooked or not reported. During the research, 143 species of diatoms were identified, including two new representatives of the genus Luticola: L. bryophila sp. nov. with relatively large central area and short distal raphe endings and L. confusa sp. nov. characterized by the presence of small depressions on central raphe endings. Both are described herein based on light and scanning electron microscopy observations and compared to similar taxa based on literature data. Basic morphological data for almost all the diatom taxa are noted, and their habitat requirements, and photographic documentation are also presented. The present research showed that the occurrence of diatom assemblages on tree trunks is influenced by various factors like host tree species, the area where the host tree grows, and the availability of suitable microhabitats within the trunk. However, the species composition of this assemblages depends mainly on the tree species.
Bacillariophyceae, bark chemistry, bryosphere, corticolous habitats, diversity, taxonomy
Despite over a century of study on terrestrial algae (
Many different terms are used to name algal assemblage in their terrestrial environments depending on environmental conditions and available water sources (
Bark surfaces create special microclimatic niches for algae. Thanks to cracks, they retain moisture, protect against wind, and provide shade and nutrients that are compounds from accumulated dust which dissolve in rainwater (
The aim of the study was to investigate the taxonomic diversity and ecological requirements of diatoms inhabiting various microhabitats on trunks of deciduous trees in Central Europe in areas confronting various degrees of human impact. Additionally, preferences of diatoms for host tree species and microhabitats within trunks were determined.
Samples were collected in 2017 and 2018 four times each year in the first half of April and June, and the second half of August and October from heights of 20 cm (referred to as trunk base) and 150 cm above ground level from several tree trunk microhabitats, i.e., bare bark, moss clumps, bark covered with lichens, bark with visible mats of algae (Fig.
List of studied sites with the sampled tree taxa and microhabitat type over their trunk.
Site | Tree species | Coordinates | Studied microhabitat |
---|---|---|---|
1 | Acer pseudoplatanus L. | 50°34'09.1"N, 22°03'57.5"E | bare bark, lichens |
Tilia platyphyllos Scop. | 50°34'04.1"N, 22°04'01.9"E | bare bark, lichens | |
Populus nigra L. ‘Italica’ | 50°34'08.5"N, 22°03'56.8"E | bare bark, mosses, lichens | |
2 | Acer pseudoplatanus L. | 50°34'12.1"N, 22°04'20.4"E | lichens |
Tilia cordata Mill. | 50°34'12.2"N, 22°04'20.8"E | lichens | |
Populus nigra L. | 50°34'16.4"N, 22°04'18.6"E | bare bark, mosses, lichens | |
3 | Acer pseudoplatanus L. | 50°36'13.2"N, 22°02'01.7"E | bare bark, mosses, green algae mats |
Tilia cordata Mill. | 50°35'58.2"N, 22°01'49.7"E | bare bark, mosses | |
Populus nigra L. | 50°35'59.0"N, 22°01'49.6"E | bare bark, mosses | |
4 | Acer pseudoplatanus L. | 50°01'06.7"N, 22°01'01.5"E | bare bark, lichens |
Tilia platyphyllos Scop. | 50°01'18.4"N, 22°00'56.7"E | bare bark, lichens | |
Populus nigra L. ‘Italica’ | 50°01'18.8"N, 22°01'00.6"E | bare bark, mosses, lichens | |
5 | Acer pseudoplatanus L. | 50°00'08.9"N, 22°01'54.1"E | bare bark, mosses |
Tilia cordata Mill. | 50°00'11.0"N, 22°01'54.1"E | bare bark, mosses | |
Populus nigra L. | 50°00'09.5"N, 22°01'48.3"E | bare bark, mosses, lichens, green algae mats | |
6 | Acer pseudoplatanus L. | 50°00'36.3"N, 21°59'16.0"E | bare bark, mosses |
Tilia cordata Mill. | 50°00'39.1"N, 21°59'20.5"E | bare bark, mosses | |
Populus alba L. | 50°00'42.6"N, 21°59'23.6"E | bare bark, mosses, green algae mats | |
7 | Acer pseudoplatanus L. | 49°30'10.3"N, 21°29'31.1"E | bare bark, mosses, green algae mats |
Tilia cordata Mill. | 49°30'42.8"N, 21°29'57.0"E | bare bark, mosses, lichens | |
Populus tremula L. | 49°30'58.1"N, 21°29'38.3"E | bare bark, mosses | |
8 | Acer pseudoplatanus L. | 49°37'01.8"N, 20°04'07.0"E | bare bark, mosses, lichens |
Tilia cordata Mill. | 49°37'01.4"N, 20°04'06.7"E | bare bark, mosses, lichens | |
Populus nigra L. | 49°37'02.8"N, 20°04'14.3"E | bare bark, mosses, lichens |
The samples were also used to prepare filtrates for pH and conductivity analyses. The filtrates were obtained by soaking bare bark pieces in deionized water (1:10 by weight) for 24 hours. The intact pieces of bark were used to obtain a solution similar to that forming on the bark surface that is a source of water and nutrients for corticolous organisms; in the case of trees completely covered by epiphytic mosses, the material together with them was used to obtain filtrates. Electrolytic conductivity and pH were measured with a MARTINI pH56 pH meter and a MARTINI EC59 conductometer (Milwaukee Electronics Kft.). The ions’ content was determined using a Thermo scientific DIONEX ICS–5000+DC device in the Departmental Laboratory of Analysis of Environmental Health and Materials of Agricultural Origin at the University of Rzeszów.
A modified method by
Light microscope slides were prepared by applying the cleaned diatom suspension to cover-slips that were left to dry. The dried material was mounted in synthetic Pleurax resin, Brunel Microscopes ltd. (refractive index 1.75). To better define the species composition of the assemblages analyzed, two microscope samples on coverslips were mounted on a single slide. In total, 647 samples were collected and analyzed. The diatoms were identified under a Carl Zeiss Axio Imager.A2 light microscope (LM) with a Zeiss AxioCam ICc 5 camera at 1000× magnification. For Scanning Electron Microscope (SEM) observations, the samples were coated in a Turbo-Pumped Sputter Coater Quorum Q 150OT ES with a 20 nm layer of gold and viewed under a Hitachi SU 8010 microscope.
Two microscope slides were made from each collected sample. Diatoms were identified in both slides by observations in all possible adjacent transects. During species identification, all identified valves were counted until a number of 400 was reached. Identification of species was continued for species composition also after reaching the assumed limit of 400 valves. The dominance structure and similarity analysis were determined only for samples for which a minimum of 200 valves were counted. Species with a minimum share of 10% in the assemblages were considered dominants. The remaining samples were considered unrepresentative because of the insufficient development of assemblages or their complete absence. To present the morphological variability of the observed taxa, valves dimensions were measured under light microscope using AxioVision SE62 Rel. 4.9.1 software. For range dimension of commonly occurred taxa ca. 50 specimens were measured including the biggest and the smallest observed specimens. In the case of rare taxa (observed in <10 samples) each observed specimen was measured.
Diatom diversity was analyzed using the Shannon diversity index (H’) and the Evenness index (J’). Principal Component Analysis (PCA) was performed to determine the similarity of diatom assemblages. Prior to analysis, diatom data were square root transformed. Redundancy analysis (RDA, gradient length = 1.9 SD) was performed to determine the effect of bark chemistry on diatom assemblages, but none of the parameters showed statistically significant effects on the assemblages studied (p> 0.05). All analyses (PCA, RDA) were performed using Canoco 5 (
Student’s t-test was used to analyze the significance of differences in the chemical parameters of the samples, and values at p<0.05 were considered statistically significant. All calculations were performed using Statistica 13.3 software.
Diatom terminology and identification were based on
The pH of the analyzed filtrates indicated slightly acid to neutral condition of the barks of the tree species examined. The electrolytic conductivity values measured in the filtrates of all the trees analyzed indicated a very wide range (from 49 µm cm-1 to 5 846 µS cm-1), regardless of sampling height (Table
Chemical parameters measured in filtrates obtained from bark of studied trees, given range (minimum and maximum), and median (brackets), bold indicates value for samples from trunk bases. * – indicates a parameter in which differences between the studied heights were statistically significant (p> 0.05).
Tree taxon | Acer | Tilia | Populus |
---|---|---|---|
pH | 5.3–7.3 (6.3) | 4.7–7.3 (6.0)* | 4.8–7.5 (6.3)* |
4.8–7.5 (6.4) | 4.8–7.5 (6.4)* | 5.1–7.4 (6.5)* | |
Cond. [μS cm–1] | 49–2305 (167)* | 49–462 (202) | 52–2305 (323.1) |
64–604 (228)* | 69–5846 (338) | 39–1199 (332.1) | |
Cl- [mg/l] | 0.5–29.9 (3.3) | 1.1–20.7 (6.3) | 0.442–103.7 (9.4) |
0.5–14.5 (3.3) | 0.2–71.7 (9.0) | 0.232–98.6 (8.8) | |
NO3- [mg/l] | <0.001–4.6 (1.5) | <0.001–4.6 (2.5) | <0.001–159.3 (3.4) |
<0.001–16.5 (1.2) | <0.001–89.9 (5.2) | <0.001–42.2 (2.3) | |
PO43- [mg/l] | <0.001–44.8 (11.1) | <0.001–34.8 (10.1)* | <0.001–36.7 (8.8)* |
2.7–42.5 (14.1) | <0.001–39.2 (16.3)* | <0.001–64.0 (14.3)* | |
SO42- [mg/l] | 0.7–55.5 (7.2) | <0.001–61.5 (18.6) | <0.001–400.9 (20.9) |
0.9–14.9 (6.5) | 0.6–3 278.2 (66.7) | 0.2–10.7 (20.8) | |
Na+ [mg/l] | 0.3–12.4 (2.5) | 0.4–12.2 (3.1)* | 0.273–59.2 (6.8) |
0.3–18.5 (3.4) | 0.3–21.0 (5.7)* | 0.3–55.3 (7.4) | |
K+ [mg/l] | 10.2–137.9 (33.7) | 9.509–68.1 (35.9) | 7.8–752.2 (86.3) |
11.2–161.4 (38.4) | <0.001–1510.2 (65.8) | <0.001–386.3 (75.2) | |
Ca2+ [mg/l] | 0.6–48.2 (6.7) | 0.1–26.4 (10.6) | 0.3–56.5 (8.5) |
0.2–34.7 (8.0) | 0.3–317.7 (16.4) | 0.3–28.9 (8.7) | |
Mg2+ [mg/l] | 0.2–18.5 (2.4) | 0.3–10.6 (2.7) | 0.1–37.1 (3.5) |
0.1–14.0 (2.6) | 0.6–62.8 (3.8) | 0.2–10.7 (3.0) | |
NH4+ [mg/l] | <0.001–28.5 (3.8)* | 0.1–23.7 (5.6) | <0.001–12.3 (2.3)* |
0.7–32.8 (7.3)* | <0.001–228.9 (12.7) | <0.001–103.0 (5.8)* |
Rectangular in girdle view. Valves linear to linear lanceolate with weakly protracted and moderately rounded apices, smaller specimens without protracted apices. Valve length 10–25 µm, and valve width 4–6 µm. Axial area narrow linear, slightly expanded near central area. Central area wide and rounded, bordered by 3–4 areolae. Ghost areolae commonly present in central area. Round isolated pore located half way between valve center and margin. Raphe branch straight with both endings clearly curved to site opposite to isolated pore. Distal raphe endings short, not continuing onto mantle. Internal raphe slit simple and straight, distal endings form slightly developed helictoglossae. Striae number 18–20 in 10 µm composed of 2–3 same sized, rounded to slightly elongated areolae. Single row of areolae present also on valve mantle. Internally areolae covered by hymen forming continuous strip, separated by not thickened virgae. Internally small lipped opening of isolated pore visible. Marginal channel located on valve face/mantle junction occluded by hymenes and visible internally.
Holotype
: Slide SZCZ 28844 and unmounted material with the same number stored in A. Witkowski Diatom Collection of the Institute of Marine and Environmental Sciences, University of Szczecin, holotype specimen designated here in Fig.
Isotype : Slide no. 2017/18 and unmounted material with the same number at the University of Rzeszów, Poland.
Stalowa Wola, Podkarpacie Province, Poland, 50°34'16.4"N, 22°04'18.6"E, leg. M. Rybak.
The name refers to the occurrence of the species mainly in terrestrial bryophytes.
Species observed at most of the sites studied, always in single specimens, mainly in samples of bryophytes from trunk bases.
Luticola sparsipunctata Levkov, Metzeltin & Pavlov (
Valves elliptic to elliptic-lanceolate with rounded apices, rectangular in girdle view. Valve length 9–22 µm, and valve width 4.5–5.5 µm. Axial area narrow and linear, central area elliptic bordered by 3–4 areolae. Round isolated pore located halfway between valve center and margin. Raphe branch straight. Proximal raphe endings deflected to site opposite to stigma with small rounded depressions. Distal raphe endings hooked continuing onto valve mantle. Internally raphe slit simple and straight, distal endings form slightly developed helictoglossae. Striae number 20–22 in 10 µm composed mainly of 4 areolae, single row of areolae also present on valve mantle. On apices row of mantle areolae interrupted by distal raphe endings. Internally areolae covered by hymen forming continuous strip, separated by not thickened virgae. Internally small lipped opening of isolated pore visible. Marginal channel located on valve face/mantle junction occluded by hymenes and visible internally.
Holotype
: Slide SZCZ28845 and unmounted material with the same number stored in A. Witkowski Diatom Collection of the Institute of Marine and Environmental Sciences, University of Szczecin, holotype specimen designated here in Fig.
Isotype : Slide no. 2018/454 and unmounted material with the same number at the University of Rzeszów, Poland.
Stalowa Wola, Podkarpacie Province, Poland, 50°36'13.2"N, 22°02'01.7"E, leg. M. Rybak.
The name refers to possible past confusions in identification of the species described with other small taxa with elliptic-lanceolate valves.
Species observed at all sites studied, always in the form of individual specimens. It mainly occurred in samples taken from the base of the trunks of the trees studied.
Luticola imbricata (W.Bock) Levkov, Metzeltin and Pavlov (
During the study 143 diatom taxa representing 39 genera were identified (Table
LM microphotographs of Achnanthes coarctata (A–I), Meridion circulare (J), Pseudostaurosira brevistriata (K), Eunotia botuliformis (L, M), Cocconeis pediculus (N, O), C. lineata (P, K), Lemnicola hungarica (R, S), Planothidium lanceolatum (T–X) and P. frequentissimum (Y–AC). Scale bar: 10 µm.
LM microphotographs of Humidophila contenta (A–G), H. gallica (H–P), H. brekkaensis (Q–Z), H. irata (AA–AF), H. perpusilla (AG–AL), Fallacia insociabilis (AM–AS), F. enigmatica (AT), Microcostatus aerophilus (AU–AZ), Mayamaea excelsa (BA, BB), M. atomus (BC–BJ), M. asellus (BK–BM), M. fossalis (BN–BP), M. permitis (BQ–BS), Cavinula cocconeiformis (BT) and Geissleria ignota (BU, BV). Scale bar: 10 µm.
LM microphotographs of Luticola acidoclinata (A–H), L. poulickovae (I), L. cohnii (J, K), L. pseudokotschyi (L), L. spinifera (M–O), L. pitranensis (P–S), L. rotunda (T–AA), Luticola sp. (AB–AD), L. imbricata (AE–AJ), L. micra (AK–AP), L. cf. vesnae (AR–AX) and L. obscura (AY–BD). Scale bar: 10 µm.
LM microphotographs of Luticola nivalis (A–G), L. pseudonivalis (H–J), L. binodeformis (K), L. pulchra (L–S), L. kemalii (T–V), L. lecohui (W–AA), L. vanheurckii (AB–AE), L. undulata (AF), L. nivaloides (AG–AM), L. cholnokyi (AN, AO), L. ventricosa MT1 (AP–AV) and L. ventricosa MT2 (AW–BA). Scale bar: 10 µm.
LM microphotographs of Pinnularia borealis var. borealis (A–E), P. borealis var. subislandica (F–H), P. dubitabilis (I), P. sinistra (J–M), P. schoenfelderi (N–R), P. frauenbergiana var. caloneiopsis (S–U), P. obscura (V–AC), Caloneis cf. langebertalotioides (AD–AH), P. perirrorata (AI–AL), C. vasileyevae (AM–AP) and C. lancettula (AQ–AT). Scale bar: 10 µm.
LM microphotographs of Tryblionella apiculata (A, B), T. debilis (C–E), Nitzschia harderi (F–I), N. solgensis (J), N. amphibia (K–M), N. amphibia f. apiculata (N–P), N. communis (Q), N. cf. frustulum (R–T), N. pusilla (U–Z), Surirella angusta (AA–AD), S. minuta (AE, AF) and S. terricola (AG–AJ). Scale bar: 10 µm.
Complete list of documented diatom taxa with measured dimension ranges (Length / Width; striae/10µm), frequency of occurrence in samples (Freq. [%]), minimum and maximum relative abundance (Min-Max) at sycamore maples (Acer), lindens (Tilia) and poplars (Populus). Bold indicates data from samples collected at 20 cm above ground level. + idicates observation of species in sample with unrepresentative assemblages.
Taxa | Dimensions | Acer | Tilia | Populus | |||
---|---|---|---|---|---|---|---|
Freq. | Min-Max | Freq. | Min-Max | Freq. | Min-Max | ||
Achnanthes coarctata (Brébisson & W.Smith) Grunow | 15–32 / 4–7; | 21 | 0.21–0.48 | 22 | 0.31–0.32 | 27 | 0.22–1.42 |
11–13 | 8 | 0.30–0.34 | 25 | 0.10–2.47 | 20 | 0.19–1.38 | |
Achnanthidium minutissimum (Kützing) Czarnecki | 5–18 / 3; | 11 | 0.24–0.48 | 4 | + | 8 | – |
21–22 | 9 | 0.21–0.31 | 12 | 0.32–7.41 | 15 | 0.19–0.49 | |
Amphora pediculus (Kützing) Grunow | 7–10 / 2.7–3; | – | – | – | – | – | – |
17–18 | 1 | 0.32 | 5 | 0.41 | 1 | + | |
Aulacoseira spp. | – | 14 | 0.25–0.31 | 9 | 0.20 | 5 | 0.12–0.34 |
20 | 0.07–0.23 | 16 | 0.18–0.32 | 10 | 0.17–0.33 | ||
Caloneis aerophila W.Bock | 12–19 / 3.5–4.5; | 1 | + | ||||
19–23 | – | – | |||||
Caloneis lancettula (Schulz) Lange-Bertalot & Witkowski | 13–25 / 4–4.5; | 4 | 0.37–0.48 | 1 | + | 2 | – |
23–26 | 2 | 0.17–0.21 | 3 | + | 3 | 0.65 | |
Caloneis cf. langebertalotioides Reichardt | 17–26 / 4.5–5; | 1 | 0.31 | – | + | 1 | + |
26 | – | 0.25 | 1 | 0.41 | 3 | 0.17–0.29 | |
Caloneis leptosoma (Grunow) Krammer | 23.5–32.5 / 5–6; | – | – | – | – | ||
14–16 | 1 | 0.26 | 1 | + | |||
Caloneis vasileyevae Lange-Bertalot, Genkal & Vekhov | 12–18 / 4–4.5; | 1 | + | ||||
27–30 | – | – | |||||
Cavinula cocconeiformis (W.Gregory & Greville) D.G.Mann & A.J.Stickle | 21–23.5 / 10; | 1 | 0.30 | ||||
27 | – | – | |||||
Cocconeis euglypta Ehrenberg | 8–15 / 7–10; | 1 | + | 1 | + | ||
14–22 | 6 | + | – | – | |||
Cocconeis lineata Ehrenberg | 8–15 / 8–11; | 5 | 0.26–0.37 | 4 | + | 2 | 0.32 |
14–26 | 1 | 0.17 | 9 | 0.31–2.47 | 3 | 0.23 | |
Cocconeis pediculus Ehrenberg | 17–26 / 8–11; | 2 | + | – | – | ||
18 | 4 | 0.32 | 1 | 0.47 | |||
Cocconeis pseudolineata (Geitler) Lange-Bertalot | 7–20 / 7–11; | – | – | 2 | + | – | – |
15 | 1 | 0.29 | 1 | + | 1 | 0.23 | |
Cosmioneis pusilla (W.Smith) D.G.Mann & A.J.Stickle | 22.5–26 / 13–15; | 1 | + | ||||
15–16 | – | – | |||||
Cyclostephanos dubius (Hustedt) Round | – | 22 | 0.16–0.50 | 19 | + | 14 | 0.22–0.37 |
17 | 0.22–0.48 | 26 | 0.31–2.47 | 8 | 0.17–0.37 | ||
Epithemia adnata (Kützing) Brébisson | 17–22.5 / 7–9; | 3 | 0.21–0.33 | – | – | 1 | + |
14 | 2 | 0.17–0.23 | 1 | 0.41 | 2 | 0.49 | |
Eunotia botuliformis F.Wild, Nörpel & Lange-Bertalot | 6–26 / 3–3.5; | – | – | – | – | ||
16–19 | 8 | 0.21–0.37 | 1 | + | |||
Eunotia minor (Kützing) Grunow | 12.5–31.5 / 4–6; | 1 | + | – | – | ||
10–12 | – | – | 1 | 0.33 | |||
Fallacia enigmatica (H.Germain) Lange-Bertalot & Werum | 8.8 / 2–2.2; | – | – | 2 | – | ||
not visible in LM | 1 | + | – | + | |||
Fallacia insociabilis (Krasske) D.G.Mann | 6.5–21 / 4.5–6.5; | 2 | 0.31–0.66 | 1 | – | 2 | 0.47 |
22–25 | 11 | 0.17–1.30 | 6 | 0.41 | 3 | 0.22–0.49 | |
Geissleria ignota (Krasske) Lange-Bertalot & Metzeltin | 22.5–24 / 5; | – | – | ||||
13–14 | 1 | 0.16 | |||||
Gomphonella olivacea (Hornemann) Rabenhorst | 12–23 / 5–6; | 1 | 0.32 | – | – | – | – |
10–11 | – | – | 1 | + | 1 | + | |
Gomphonema acuminatum Ehrenberg | 22 / 7; | 1 | 0.24 | – | – | ||
12 | – | – | 1 | + | |||
Gomphonema amoenum Lange-Bertalot | 30–35 / 9–10; | 1 | 0.31 | – | – | ||
10–11 | 1 | 0.32 | 1 | 0.24 | |||
Gomphonema drutelingense Reichardt | 20–24.5 / 6.5–7; | – | – | ||||
11 | 1 | + | |||||
Gomphonema micropus Kützing | 20–26 / 7–7.5; | 2 | 0.13 | 1 | + | 1 | + |
10–12 | 4 | 0.26–0.29 | 7 | 0.20–1.23 | 4 | 0.32–0.93 | |
Gomphonema parvulum (Kützing) Kützing | 10–15 / 6–7; | 1 | 0.24– | – | – | 2 | – |
11–13 | – | 2 | + | 1 | 0.31 | ||
Halamphora montana (Krasske) Levkov | 12–20 / 3.5–5.5; | 18 | 0.20–0.34 | 13 | 0.31–0.32 | 16 | 0.17–3.79 |
not visible in LM | 21 | 0.17–2.08 | 16 | 0.10–0.41 | 16 | 0.17–0.65 | |
Hantzschia abundans Lange-Bertalot | 35–74.5 / 6–9.5; | 47 | 0.21–2.81 | 51 | 0.30–0.61 | 51 | 0.12–6.16 |
19–20 | 43 | 0.17–9.95 | 77 | 0.20–2.40 | 65 | 0.16–6.92 | |
Hantzschia amphioxys (Ehrenberg) Grunow | 12–45 / 4.5–7; | 88 | 0.20–23.13 | 84 | 0.30–2.76 | 87 | 0.12–93.90 |
21–27 | 94 | 0.14–58.82 | 99 | 0.20–29.94 | 91 | 0.16–88.10 | |
Hantzschia calcifuga Reichardt & Lange-Bertalot | 28–85 / 6.5–7.7; | 18 | 0.21–23.18 | 20 | + | 18 | 0.17–0.47 |
16–19 | 37 | 0.18–4.02 | 25 | 0.18–4.12 | 22 | 0.22–21.80 | |
Hantzschia dorgaliensis Lange-Bertalot, Cavacini, Tagliaventi & Alfinito | 60 / 6.7; | – | – | ||||
18–19 | 1 | + | |||||
Hantzschia aff. stepposa Maltsev & Kulikovskiy | 33 / 5; | – | – | ||||
25 | 1 | + | |||||
Hantzschia subrupestris Lange-Bertalot | 26.7–81 / 6.7–9; | 9 | 0.25–0.66 | 10 | + | 13 | 0.35–0.95 |
14–17 | 15 | 0.18–2.99 | 16 | 0.20–0.65 | 20 | 0.16–1.01 | |
Humidophila brekkaensis (Petersen) Lowe et al. | 8–19.5 / 6–6.5; | 1 | – | 1 | + | 2 | – |
not visible in LM | 5 | 0.24–12.5 | 5 | + | 3 | 0.34 | |
Humidophila contenta (Grunow) Lowe et al. | 5–13 / 2.5–3.2; | 53 | 0.20–23.13 | 32 | 7.50–58.51 | 40 | 0.56–59.25 |
not visible in LM | 68 | 0.02–34.05 | 52 | 0.30–79.22 | 72 | 0.23–81.77 | |
Humidophila gallica (W.Smith) Lowe et al. | 4–10 / 2–3; | 2 | 0.31 | 9 | 0.20 | 10 | 0.35–10.90 |
not visible in LM | 3 | 0.22–0.34 | 7 | + | 15 | 0.22–4.12 | |
Humidophila irata (Krasske) Lowe et al. | 15–21 / 6.2–6.5; | 6 | 0.24–0.31 | 2 | + | 2 | 0.24 |
not visible in LM | 25 | 0.17–1.01 | 17 | 0.10–0.41 | 6 | 0.19–0.22 | |
Humidophila perpusilla (Grunow) Lowe et al. | 6–13.5 / 4–5; | 1 | + | 5 | 0.84 | ||
not visible in LM | 2 | + | 10 | 2.21–19.06 | |||
Lemnicola hungarica (Grunow) Round & Basson | 8–13 / 4–6; | – | – | 1 | + | – | – |
18–21 | 1 | 0.25–0.34 | 2 | + | 1 | 0.49 | |
Luticola acidoclinata Lange-Bertalot | 10–32 / 4.8–8.7; | 81 | 0.31–98.77 | 50 | 2.50–38.21 | 55 | 1.02–97.33 |
18–23 | 87 | 0.26–99.91 | 69 | 1.62–94.12 | 68 | 7.73–91.22 | |
Luticola binodeformis Levkov, Metzeltin & Pavlov | 12–15.5 / 4–4.5; | – | – | ||||
21–22 | 1 | 0.33 | |||||
Luticola blancoi Levkov, Tofilovska, C.E.Wetzel, Mitić-Kopanja & Ector | 18–21 / 6.5; | – | – | – | – | ||
20–21 | 1 | + | 1 | + | |||
Luticola bryophila M.Rybak, Czarnota & Noga, sp. nov. | 10–25 / 4–6; | 5 | 0.26 | 8 | + | 5 | 0.24 |
18–20 | 14 | 0.17–0.66 | 11 | 0.25–0.65 | 17 | 0.22–7.73 | |
Luticola cholnokyi Levkov, Metzeltin & Pavlov | 15–18 / 6.5; | – | – | ||||
20–21 | 1 | 0.16 | |||||
Luticola cohnii (Hilse) D.G.Mann | 17.5–28.5 / 8.5–10; | – | – | – | – | ||
20–21 | 1 | 0.31 | 1 | + | |||
Luticola confusa M.Rybak & Czarnota, sp. nov. | 9–22 / 4.5–6; | 20 | 0.24–0.32 | 13 | – | 20 | 0.35–3.32 |
20–22 | 25 | 0.18–10.45 | 0.18-2.00 | 19 | 0.17–0.53 | ||
Luticola imbricata (W.Bock) Levkov, Metzeltin & Pavlov | 15–17 / 5.5–7; | – | – | 1 | + | – | – |
20 | 2 | 0.30–0.66 | 1 | + | 1 | + | |
Luticola kemalii Solak & Levkov | 12–16 / 5.6–7; | 2 | – | – | 2 | + | |
20–22 | – | 1 | + | 2 | 0.28 | ||
Luticola lecohui Levkov, Tofilovska, C.E.Wetzel, Mitic-Kopanja & Ector | 15–23.5 / 7–8; | 1 | + | 1 | + | ||
20–21 | – | – | 1 | + | |||
Luticola micra Levkov, Metzeltin & Pavlov | 7.5–13 / 3.8–4.5; | 6 | 0.24–0.32 | 5 | 0.30–0.31 | 7 | 0.24–0.28 |
22–24 | 9 | 0.20–0.52 | 5 | 0.28–0.30 | 2 | 0.19 | |
Luticola nivalis (Ehrenberg) D.G.Mann | 10–21 / 5.8–7.5; | 16 | 0.28–0.36 | 15 | 0.32 | 21 | 0.17–0.95 |
19–21 | 17 | 0.25–0.68 | 9 | 0.10 | 33 | 0.22–0.69 | |
Luticola nivaloides (W.Bock) Denys & De Smet | 15–23.5 / 6.5–8; | 1 | 0.48 | 1 | + | 6 | 0.47 |
18–19 | – | – | 4 | 0.32 | 8 | 0.17–0.29 | |
Luticola obscura Levkov, Tofilovska, C.E.Wetzel, Mitić-Kopanja & Ector | 10–24.5 / 5–7; | 20 | 0.48–0.48 | 28 | 0.30–0.31 | 15 | 0.34 |
19–22 | 26 | 0.17–2.24 | 36 | 0.18–1.53 | 29 | 0.19–7.54 | |
Luticola pitranensis Levkov, Metzeltin & Pavlov | 15–22.5 / 5.5–6.5; | – | – | ||||
20–22 | 2 | 0.17–0.20 | |||||
Luticola poulickovae Levkov, Metzeltin & Pavlov | 22 / 6; | – | – | ||||
21 | 1 | + | |||||
Luticola pulchra (McCall) Levkov, Metzeltin & Pavlov | 10–20 / 5.9–6.4; | 1 | 0.32 | 7 | 0.31 | 15 | 1.90 |
20–24 | 6 | 0.22–0.34 | 9 | 0.25–0.30 | 13 | 0.19–0.33 | |
Luticola pseudonivalis (W.Bock) Levkov, Metzeltin & Pavlov | 13.2–16.5 / 5–6; | 4 | + | 2 | 0.31 | 1 | 0.47 |
24 | 1 | 0.28 | – | – | – | – | |
Luticola rotunda Solak & Levkov | 12–15.5 / 6–6.5; | 2 | 0.20–0.31 | 1 | + | 2 | – |
19–20 | 8 | 0.31–0.68 | 1 | + | 1 | 0.22–0.29 | |
Luticola sparsipunctata Levkov, Metzeltin & Pavlov | 9.5–27 / 4.5–7; | 14 | 0.28–0.40 | 19 | 0.31 | 25 | 0.12–1.42 |
18–20 | 24 | 0.17–3.67 | 27 | 0.18–0.34 | 32 | 0.19–7.80 | |
Luticola spinifera (W.Bock) L.Denys & W.H.De Smet | 12–14 / 7–8; | 1 | + | ||||
16 | – | – | |||||
Luticola undulata (Hilse) D.G.Mann | 19–22.5 / 7.5–7.8; | – | – | – | – | ||
24–25 | 1 | + | 1 | 0.49 | |||
Luticola vanheurckii Van de Vijver & Levkov | 14.5–19 / 5.5–7.3; | 10 | + | 6 | + | ||
18–21 | 16 | 0.25–0.65 | 3 | 0.22–0.29 | |||
Luticola ventricosa (Kützing) D.G.Mann MT1 | 10–23 / 5.5–7; | 20 | 0.23–0.40 | 16 | 0.30–0.31 | 15 | 0.24–3.79 |
19–22 | 11 | 0.22–10.95 | 17 | 0.25–0.32 | 27 | 0.17–2.07 | |
Luticola ventricosa (Kützing) D.G.Mann MT2 | 9.2–22 / 5–7; | 10 | 0.26–0.61 | 23 | 0.30–0.31 | 35 | 0.12–1.42 |
19–22 | 13 | 0.02–0.82 | 43 | 0.19–62.21 | 31 | 0.19–0.69 | |
Luticola cf. vesnae Levkov, Metzeltin & Pavlov | 10–23.7 / 5–7.2; | 8 | 0.16–0.25 | 7 | + | 9 | 0.12–0.34 |
20–24 | 24 | 0.18–7.12 | 18 | 0.18–0.32 | 13 | 0.28–0.97 | |
Luticola sp. 1 | 14–18 / 5.5–7; | – | – | 1 | 0.31 | 2 | 0.25 |
18–23 | 9 | 0.34–0.37 | 9 | 0.32–0.41 | 5 | 0.16–0.19 | |
Luticola sp. 2 | - | – | + | – | – | –1 | + |
1 | 0.28 | 1 | + | 1 | 0.28 | ||
Mayamaea asellus (Weinhold & Hustedt) Lange-Bertalot | 12–16.5 / 5.5–6; | 1 | 0.32 | 2 | + | 4 | + |
16–18 | 4 | + | 7 | 0.25–0.32 | 2 | 0.28–0.29 | |
Mayamaea atomus (Kützing) Lange-Bertalot | 7–13 / 4–5; | 5 | + | 9 | 0.31 | 7 | 0.22–0.95 |
18–22 | 23 | 0.17–6.86 | 37 | 0.25–0.41 | 15 | 0.17–0.49 | |
Mayamaea excelsa (Krasske) Lange-Bertalot | 11–14.5 / 5–7; | 2 | 0.22 | – | – | 1 | + |
16–17 | 5 | 0.26–0.31 | 7 | + | 3 | 0.26–0.33 | |
Mayamaea fossalis var. fossalis (Krasske) Lange-Bertalot | 9–11.5 / 3–4; | 1 | + | 1 | + | 1 | + |
17–19 | 3 | 0.17–0.41 | 4 | + | 1 | 0.33 | |
Mayamaea fossalis var. obsidialis (Hustedt) Lange-Bertalot | 9–11 / 4.5; | – | – | ||||
18 | 3 | 0.18 | |||||
Mayamaea permitis (Hustedt) K.Bruder & Medlin | 7–12 / 3.5–4.5; | 1 | + | 111 | 1 | 2 | + |
ca. 35 | 7 | 0.17–2.69 | 11 | 0.20 | 2 | 0.19 | |
Meridion circulare (Greville) C.Agardh | 13–24 / 5–6 | 3 | 0.20–0.31 | 7 | + | 2 | 0.24 |
2 | + | 9 | 0.41 | 1 | + | ||
Microcostatus aerophilus Stanek-Tarkowska, Noga, C.E.Wetzel & Ector | 6–9.5 / 2.5–3.5; | 1 | + | – | – | ||
not visible in LM | – | – | 5 | + | |||
Muelleria islandica (Østrup) Lange-Bertalot | 19.5–30 / 6.7–7.7; | 2 | + | 2 | + | 3 | + |
22–25 | 5 | 0.17–0.35 | 3 | + | 2 | + | |
Muelleria sasaensis Levkov, Vidaković, Cvetkoska, Mitić-Kopanja, Krstić, Van de Vijver & Hamilton | 22.5–29.5 / 5.8–6.2; | – | – | 3 | + | 1 | – |
23–24 | 3 | 0.24–1.49 | 1 | + | 3 | 0.25 | |
Muelleria terrestris (J.B.Petersen) Spaulding & Stoermer | 23.5–26 / 5.2–6; | 3 | 0.24 | 2 | + | 3 | + |
18–19 | 3 | 0.23–0.64 | 3 | 0.50 | 3 | v | |
Muelleria undulata (Krasske) Levkov, Hamilton & Van de Vijver | 12–22 / 4.3–5; | 3 | + | 1 | + | – | – |
26–28 | 3 | 0.17–3.98 | – | – | 2 | + | |
Navicula bjoernoeyaensis Metzeltin, Witkowski & Lange-Bertalot | 17–18 / 3; | 1 | + | – | – | 1 | 0.34 |
18 | – | – | 1 | + | 3 | 0.23 | |
Navicula gregaria Donkin | 15.5–22 / 6–7; | – | – | 1 | + | 1 | 0.12 |
16 | 1 | 0.31 | 1 | 0.41 | 3 | 0.29–0.43 | |
Navicula lundii Reichardt | 14–25 / 4.2–6; | – | – | 11 | 0.47 | ||
15 | 2 | 0.24–0.50 | 0.24 | ||||
Navicula neowiesneri Chaudev & Kulikovskyi | 12–32 / 4.5–6; | 38 | 0.16–0.80 | 36 | 0.20–0.32 | 43 | 0.12–5.69 |
11–13 | 35 | 0.18–2.03 | 40 | 0.18–1.75 | 38 | 0.17–4.14 | |
Navicula pseudowiesneri Chaudev & Kulikovskyi | 11–24 / 4–5; | 30 | 0.16–0.62 | 21 | 0.18–0.24 | 22 | 0.12–1.12 |
11–13 | 35 | 0.18–2.03 | 23 | 0.18–1.02 | 12 | 0.17–0.35 | |
Navicula tenelloides Hustedt | 14–18 / 3–3.5; | – | – | 1 | + | 1 | + |
16 | 1 | 0.25 | 1 | 0.41 | – | – | |
Navicula veneta Kützing | 12–25.5 / 4.5–5.5; | 1 | + | – | – | 1 | 0.12 |
13–16 | 2 | 0.32–0.41 | 2 | 0.32 | 4 | 0.22–0.49 | |
Neidium alpinum Hustedt | 15–29 / 4.5–5; | – | – | ||||
ca. 37 | 1 | + | |||||
Neidium perforatum Schimanski | 15.5–26 / 4.5–5.5; | 2 | 0.31–0.33 | ||||
21–23 | 6 | 0.18–0.37 | |||||
Nitzschia amphibia Grunow | 9–28 / 4–5.5; | 9 | 0.21–0.48 | 6 | 0.31 | 8 | 0.34–0.47 |
15–18 | 7 | 0.25–0.41 | 7 | 0.32 | 8 | 0.24–0.49 | |
Nitzschia amphibia f. rostrata Hustedt | 12–15 / 3.5–4; | 1 | – | – | – | – | |
18–20 | – | 1 | 0.32 | 1 | + | ||
Nitzschia communis Rabenhorst | 15–20 / 4; | 1 | 0.24 | 1 | + | ||
not visible in LM | – | – | 3 | 0.22–0.29 | |||
Nitzschia harderi Hustedt | 19–36 / 3–4; | 1 | 0.25 | ||||
not visible in LM | 1 | 1.48 | |||||
Nitzschia pusilla Grunow | 7–22 / 2.5–3.5; | 5 | 0.21–0.36 | 5 | 0.20 | 2 | + |
not visible in LM | 11 | 0.18–1.59 | 5 | 0.10 | 7 | 0.22–0.33 | |
Nitzschia cf. frustulum (Kützing) Grunow | 4–16.5 / 3; | 15 | 0.25–0.36 | 9 | – | 4 | 0.12 |
25–27 | 6 | 0.30 | 16 | 0.32–0.34 | 14 | 0.22–6.45 | |
Nitzschia solgensis Cleve-Euler | 11.5–24 / 3–4; | 1 | 0.24 | – | – | 3 | 0.33 |
21–23 | 2 | 0.30 | 1 | + | 3 | 0.19–0.29 | |
Nitzschia cf. supralitorea Lange-Bertalot | 10–20 / 2.5–3.5; | – | – | 2 | 1.42 | ||
27–30 | 1 | + | – | – | |||
Nitzschia linearis W.Smith | 50–55 / 6; | – | – | ||||
28–29 | 2 | 0.22–1.74 | |||||
Orthoseira dendroteres (Ehrenberg) Genkal & Kulikovskiy | Ø – 7–26; | 36 | 0.24–95.69 | 7 | + | 9 | 0.17–3.59 |
20–22 | 39 | 0.23–95.36 | 17 | 0.82 | 16 | 0.17–72.02 | |
Orthoseira roeseana (Rabenhorst) Pfitzer | Ø – 8–24; | 4 | 0.24–0.71 | 2 | + | 1 | 0.17 |
8–12 | 8 | 0.17–3.55 | – | – | 4 | 0.26–2.85 | |
Pantocsekiella cf. ocellata (Pantocsek) K.T.Kiss & E.Ács | – | 6 | 0.24–0.34 | 2 | + | 6 | 0.12–0.33 |
10 | 0.02–0.20 | 6 | + | 11 | 0.19–0.33 | ||
Pinnularia borealis var. borealisEhrenberg | 22–42 / 8–9.5; | 68 | 0.21–58.21 | 52 | 0.30–1.81 | 57 | 1.63–97.80 |
ca. 5 | 80 | 0.03–52.24 | 79 | 0.30–86.57 | 67 | 0.24–66.32 | |
Pinnularia borealis var. subislandica Krammer | 35–40 / 8.5–9; | – | – | 1 | + | 1 | 0.47 |
ca. 5 | 3 | 0.26–0.32 | 2 | 0.30 | 3 | 0.29–0.65 | |
Pinnularia brebissonii (Kützing) Rabenhorst | 10–34 / 9–12; | 1 | + | 1 | + | 2 | + |
10–13 | 3 | 0.22–0.34 | 1 | + | 2 | 0.22–0.29 | |
Pinnularia cuneola Reichardt | 24.5–30 / 7–8; | 9 | 0.28–0.34 | 3 | + | 9 | 0.34 |
10–11 | 7 | 0.23–0.32 | 11 | 0.30–0.41 | 9 | 0.17–0.49 | |
Pinnularia dubitabilis Hustedt | 40 / 9; | – | – | ||||
ca. 5 | 1 | + | |||||
Pinnularia aff. frauenbergiana var. caloneiopsis Lange-Bertalot & M.Werum | 13–22 / 4–4.5; | 3 | + | 1 | + | 2 | + |
17–18 | 2 | 0.33–1.35 | 2 | + | 1 | 0.29 | |
Pinnularia isselana Krammer | 30–45 / 7–9; | 2 | 0.28–0.36 | 2 | + | 1 | 0.24–0.47 |
10–12 | – | – | 10 | 0.32–0.41 | 5 | 0.24–0.49 | |
Pinnularia microstauron var. angusta Krammer | 42–44 / 6.5–7; | 1 | + | ||||
12–13 | – | – | |||||
Pinnularia microstauron var. rostrata Krammer | 35 / 6.5; | 1 | + | ||||
11 | – | – | |||||
Pinnularia obscura Krasske | 9–35 / 3–5; | 5559 | 0.21–1.95 | 29 | 0.20–0.31 | 3 | 0.24–1.90 |
10–13 | 0.02–26.48 | 73 | 0.18–9.48 | 38 | 0.16–2.03 | ||
Pinnularia perirrorata Krammer | 12–25 / 4; | – | – | 1 | + | ||
16–18 | 5 | 0.25–0.27 | 7 | 0.30 | |||
Pinnularia schoenfelderi Krammer | 19–34 / 5–6.5; | 10 | 0.22–0.50 | 11 | + | 6 | 0.33 |
14–16 | 11 | 0.22–0.37 | 20 | 0.32–2.47 | 7 | 0.23–0.32 | |
Pinnularia sinistra Krammer | 17–35 / 4.5–6; | 3 | 0.21–0.36 | 1 | + | 2 | + |
11–13 | 6 | 0.27–0.37 | 8 | 0.18 | 2 | + | |
Placoneis hambergii (Hustedt) K.Bruder | 14–22 / 5–7; | 1 | + | – | – | ||
13–16 | 4 | 0.26–0.30 | 3 | 0.41 | |||
Planothidium frequentissimum (Lange-Bertalot) Lange-Bertalot | 4–25 / 3.5–6; | 6 | 0.16–0.36 | 5 | 0.31 | 8 | 0.22–2.37 |
14–17 | 5 | 0.21–0.30 | 22 | 0.30–2.47 | 11 | 0.19–1.69 | |
Planothidium lanceolatum (Brébisson & Kützing) Lange-Bertalot | 7–25 / 4–6.5; | 5 | 0.21–0.30 | 5 | 0.30 | 2 | 0.12 |
13–15 | 3 | 0.29–0.30 | 8 | 0.30–3.29 | 7 | 0.22–3.72 | |
Rhoicosphenia abbreviata (C.Agardh) Lange-Bertalot | – | – | – | – | – | ||
1 | + | 1 | + | ||||
Reimeria sinuata (W.Gregory) Kociolek & Stoermer | 9–14 / 3.5–5.5; | – | – | – | – | ||
9–13 | 1 | 0.29 | 1 | + | |||
Sellaphora atomoides (Grunow) Wetzel & Van de Vijver | 6–12 / 3–4; | 5 | 0.31–0.36 | 7 | + | 4 | 0.12–1.42 |
22–25 | 8 | 0.17–0.41 | 14 | 0.41 | 8 | 0.12–0.33 | |
Sellaphora harderi (Hustedt) J.Foets & C.E.Wetzel | 5.5–12 / 3–4; | – | – | – | – | 1 | + |
32–35 | 1 | 0.28 | 2 | + | – | – | |
Sellaphora nana (Hustedt) Lange-Bertalot, Cavacini, Tagliaventi & Alfinito | 15–18.5 / 4–4.5; | 2 | 0.30 | – | – | 1 | 0.47 |
38 | 1 | 0.41 | 3 | + | – | – | |
Sellaphora nigri (De Notaris) C.E.Wetzel & Ector | 5–10 / 4; | 1 | 0.47 | ||||
28–30 | 1 | + | |||||
Sellaphora subseminulum (Hustedt) Wetzel | 7–14 / 3.2–3.8; | 1 | + | 2 | 0.31 | 1 | + |
23–25 | 8 | 0.19–1.23 | 15 | 0.41–3.29 | 5 | 0.22–0.34 | |
Stauroneis borrichii (J.B.Petersen) J.W.G.Lund | 10–26 / 3.8–5; | 19 | 0.22–0.33 | 22 | 0.20 | 18 | 0.17–0.95 |
22–26 | 40 | 0.20–9.97 | 43 | 0.10–1.19 | 26 | 0.19–0.49 | |
Stauroneis laterostrata Hustedt | 19–26 / 6.5–8.5; | – | – | 5 | + | ||
17–20 | 8 | 0.17–2.01 | 5 | + | |||
Stauroneis leguminopsis Lange-Bertalot & Krammer | 20–22 / 4.5; | – | – | ||||
24 | 1 | 0.31 | |||||
Stauroneis aff. lundii Hustedt | 14–19 / 4–5; | 2 | 0.20 | 4 | + | 4 | 0.17–0.22 |
23–24 | 16 | 0.22–0.59 | 12 | 0.32–1.03 | 4 | 0.22–0.29 | |
Stauroneis muriella J.W.G.Lund | 16–20 / 3–4; | 1 | + | 2 | – | – | |
22–26 | 2 | 0.26 | 1 | 1 | + | ||
Stauroneis obtusa Lagerstedt | 15–28 / 6–8; | 1 | + | 3 | + | 2 | + |
19–23 | 4 | 0.30–6.25 | 5 | 0.41 | 2 | + | |
Stauroneis parathermicola Lange-Bertalot | 8–18 / 3–4.5; | 2 | 0.32–0.34 | 1 | + | 2 | + |
20–23 | 10 | 0.17–1.01 | 12 | 0.82 | 2 | 0.22–0.24 | |
Stauroneis saprophila M.Rybak, Noga & Ector | 30–35/ 8.5–9.5; | 3 | 0.48 | 1 | + | 3 | + |
15–17 | 2 | 0.48 | 2 | + | 4 | 0.22–0.49 | |
Stauroneis separanda Lange-Bertalot & Werum | 13–14 / 3.8–4.2; | 1 | 0.30 | 1 | + | ||
ca. 28 | 1 | 0.30 | 1 | + | |||
Stauroneis thermicola (J.B.Petersen) J.W.G.Lund | 8–18 / 3–4.5; | 18 | 0.21–0.37 | 7 | + | 2 | 0.12 |
20–23 | 28 | 0.18–4.39 | 31 | 0.10–0.32 | 0.22–0.33 | ||
Surirella angusta Kützing | 16.5–42.5 / 6–9; | 3 | + | 1 | + | 2 | 0.12–0.47 |
24–27 | – | – | 2 | 0.30 | 7 | 0.16–1.16 | |
Surirella minuta Brébisson & Kützing | 9–34.5 / 8–10; | – | – | 2 | + | 2 | + |
26–28 | 1 | 0.25 | 6 | 0.41 | 3 | 0.29–0.23 | |
Surirella terricola Lange-Bertalot & E.Alles | 11–18.1 / 6.4; | 10 | 0.21–0.36 | 97 | + | 2 | + |
18–23 | 10 | 0.23–0.34 | 0.41 | 3 | 0.28–0.32 | ||
Tryblionella apiculata W.Gregory | 20–24 / 4.5–5.5; | – | – | ||||
17 | 2 | 0.49–1.08 | |||||
Tryblionella debilis Arnott & O’Meara | 12–23.5 / 7–8.5; | – | – | 11 | + | – | – |
not visible in LM | 1 | + | + | 3 | 0.22–0.49 | ||
Tryblionella hungarica (Grunow) Frenguelli | 35–42 / 5.2–6; | – | – | – | – | ||
8–10 | 1 | 0.25 | 2 | 0.22–0.29 |
Of the 647 samples collected, only in 197 were numerous occurrences of diatoms observed. Diatoms did not occur, or occurred only, as individual valves in all samples from barks covered with lichens or algal mats. Numerous diatom assemblages were observed in 74 of 283 samples from bare bark (27 from 20 cm above ground level and 47 from 150 cm above ground level). Numerous assemblages were also observed in 123 of 231 moss samples collected (43 from 20 cm above ground level and 80 from 150 cm above ground level).
Higher values of both indices studied (H’ and J’) were usually recorded for bare bark samples, and higher values of both of these indices were also recorded for samples collected from trunk bases (Fig.
Principal component analysis (PCA) revealed considerable variability in the diatom assemblages. The gradient length in analysis was 2.7. The first ordination axis explained 33.48% of the variation, the second 25.00%, the third 14.02%, and the fourth 10.14% (Fig.
Tree barks, thanks to their porosity, can absorb rainwater; therefore the solution on its surface is usually slightly acidic. On the other hand, pH reactions often depend on bark structures, which differ depending on tree species (
Of the 647 samples collected, only 197 had developed diatom communities, and only single valves were found in the remaining samples. The almost complete or complete absence of diatoms was observed in bark samples covered with visible mats of green algae. Other studies focusing on corticolous algae assemblages, in which only a few species of diatoms have been found (
Although trees growing as close as possible to each other were selected at the sites and materials from analogous microhabitats were collected from them, differences in the frequency of occurrence of diatom assemblages were clearly notable. On bare bark, diatom assemblages were found mainly in materials collected from maples and poplars at locations closest to natural sites (parks and national park buffer zones). However, diatoms were not found or only single specimens were observed in bare bark samples from site 7 (the buffer zone of Magura National Park). This was the only site where samples were collected from aspen poplar (Populus tremula L.), and it is possible that the bark of this host tree is an unfavorable habitat for diatoms. In urban conditions the trunks of poplars and maples were poorly inhabited by diatoms, and their diversity was concentrated in microhabitats created by bryophytes. Regardless of site, lindens seemed to be unsuitable for diatoms; they were abundant on this host tree only in single samples. The tree species-dependent bark water-holding capacity, which is related to bark features such as stability, texture, thickness, and hardness, directly influenced the intensity of desiccation and were important determinants of the distribution of various organisms overgrowing bark including algae (
Materials from moss microhabitats were more than half of the samples in which large numbers of diatoms were found (123 out of 197 samples). This result is similar to the study by
The developed diatom assemblages in the microhabitats analyzed were more often recorded in samples taken from trunk bases than from a height of 150 cm above ground level, and more species were also noted in samples collected from trunk bases (Table
Both of the newly described Luticola represent a group of small taxa with elliptic-lanceolate to linear elliptic valves. Many taxa representing this morphological group have been identified previously as L. mutica, which is a brackish species (
Luticola bryophila sp. nov. is most similar to the two European species L. sparsipunctata and L. tenuis. All three taxa share similar sizes and striae densities. The newly described species of the genus Luticola commonly shows ghost areolae in the central area, which are absent in both of the other taxa. Additionally, L. bryophila can be easily separated from L. tenuis based on distal raphe endings, which are short and deflected and not hooked and do not continue onto the valve mantle. Luticola sparsipunctata shows two morphotypes with different distal raphe ending morphology. The first of them has a hooked end that continues onto the valve mantle raphe endings, while the second has short and only deflected raphe endings (
Luticola confusa sp. nov. is highly similar in valve and central area shape and striae pattern to L. imbricata, L. pseudoimbricata, and L. obscura. The new species can be distinguished from L. imbricata based on its less lanceolate, narrower valves (5–9 µm width in L. imbricata vs. 4–6 µm in L. confusa) (
During the study 143 diatom taxa were identified, but most of them were found in single samples and often their share did not exceed 1% of communities. Only 16 species were common in the samples studied (in over 20% of the samples), of which 13 species formed numerous populations (from 10% in assemblages to practically monocultures). The vast majority of the species recorded were taxa commonly identified in various terrestrial environments, mainly in soils (
Assemblages noted on the trunks of all the trees studied growing in city centers and small peripheral estates were dominated by species able to develop in low moisture habitats with high osmotic stress (Hantzschia abundans, H. amphioxys, Humidophila contenta, Pinnularia borealis, P. obscura) (
Similar assemblage structures were also noted on linden and poplar at sites located in suburban park complexes and national park buffer zones. It seems that corticolous assemblages consisting mainly of drought-resistant diatom taxa are typical of these tree species regardless of the degree of tree cover in the area in which they grow.
Assemblages from sycamore maple (except those from city centers) were distinctly different from those inhabiting linden and poplars because of the strong domination of just one species, which often formed near monocultures (Fig.
Additionally, many diatom species often common in terrestrial and aerophytic habitats (numerous representatives of the genera Luticola, Mayamaea, and Muelleria; Microcostatus aerophilus; Stauroneis borrichii; S. parathermicola; S. termicola; Sellaphora harderi; S. nana, S. subseminulum) rarely developed in the environments studied. They were either observed in single samples or their share in assemblages did not exceed a few percent (
Except for taxa commonly reported from terrestrial habitats, diatoms that usually occur in aquatic environments were noted. The most common were centric taxa such as Aulacoseira spp., Pantocsekiella sp. and Cyclostephanos dubius that are recorded in freshwater planktonic assemblages. They were observed mainly as single, often damaged, frustules, but were observed in 25% of the samples analyzed. Freshwater species associated with epiphytic and epilithic communities (Achnanthidium minutissimum, Cocconeis spp., Gomphonema spp., Pseudostaurosira brevistriata) were also observed in the materials examined; however, they were noted significantly less frequently than planktonic taxa.
The present research showed that the occurrence of diatom assemblages on tree trunks is influenced by many factors, such as host tree species and the area in which these trees grow, high above soil as well as the presence of suitable microhabitats within trunks. Additionally, diatom assemblage composition was mainly influenced by the tree species.
The current research focused on communities developing on only a few tree species occurring naturally in Europe. Further research involving other tree taxa is necessary for developing a better understanding of corticolous diatom assemblages.
The first author would like to acknowledge prof. Agata Z. Wojtal and prof. Małgorzata Bąk for a detailed review of his doctoral thesis, which was the basis for the preparation of this article. The authors would also like to acknowledge Dr Kalina Manoylov (editor) and an anonymous reviewers for their work with the manuscript and their suggestions which helped to prepare the final version. The work was supported by the program of the Minister of Science and Higher Education under the program “Regional Initiative of Excellence” 2019–2023, project number 026/RID/2018/19.