Terrestrial Mosses Research Articles

Discovery of a new moss-associated diatom species, Humidophila caribaea (Bacillariophyceae: Diadesmidaceae), from terrestrial habitats of the Monts Caraïbes, Guadeloupe

During the investigation of diatom diversity of terrestrial moss samples collected on Basse-Terre, Guadeloupe, French West Indies, a new species of the genus Humidophila (Lange-Bertalot & Werum) Lowe et al. was observed. The species occurred in only one sample collected from tropical, mesophytic forests in the Monts Caraïbes and could not be identified based on the literature data. Based on the set of morphological features the species is described herein as Humidophila caribaea sp. nov. The species is characterized by the small valve size, typical for the Humidophila genus, but it has a unique morphology of the areolae with small silica warts in their lumen. Additionally, a comparison with most similar taxa known worldwide, as well as ecological notes are provided.

Local and Regional, Not Latitudinal, Variation in Microclimate and Bedrock Shapes Moss‐Associated Diatom Communities in Greenland

ABSTRACTAimGreenland is among the most rapidly changing regions on Earth, with climate change having a profound impact on its terrestrial ecosystems. Here, moss‐associated diatoms hold great potential as sensitive biological indicators to monitor responses to climate change, but their diversity, community structure and biogeography remain virtually unexplored. Our study, thus, aims to (1) explore the diversity and community structure of moss‐associated diatoms in Greenland and (2) assess the environmental and spatial variables driving their geographic distribution, establishing a baseline for their use as bio‐indicators of climate change.LocationGreenland, spanning a gradient from high to subarctic regions.TaxonMoss‐associated diatoms (Bacillariophyta).MethodsLM and SEM analysis was conducted on 175 terrestrial moss samples collected from preserved herbarium material and fresh samples (1988–2021) from high, low and subarctic localities in Greenland. Biogeographical distributions, biodiversity patterns and community structure were examined in relation to environmental and spatial factors using Kruskal–Wallis, Spearman's Rank, ordination, SIMPROF and variation partitioning analyses.ResultsA total of 544 diatom taxa (66 genera) were identified, with nearly half potentially new to science. Community structure was predominantly influenced by moisture, pH, conductivity and temperature. Local variation in microclimate and bedrock, thus, explained more variation in the diatom communities than latitude‐related environmental gradients. Surprisingly, temperature had a negative impact on diatom richness, probably due to its adverse effect on moisture, highlighting the vulnerability of Arctic moss diatoms to global warming.Main ConclusionsThis study provides the first comprehensive analysis of Greenland's moss‐associated diatoms, highlighting their high diversity and sensitivity to environmental changes. Our findings underscore their potential as indicators for monitoring climate change in the Arctic, with moisture, pH, conductivity and temperature being critical factors influencing their communities, laying the groundwork for future research and monitoring efforts.

The only terrestrial lineage in the Branchiopoda redefined: a new species of Bryospilus Frey, 1980 (Cladocera: Anomopoda) from India and adaptations of waterfleas to life on land

Abstract Only a small proportion of the world’s crustacean taxa is adapted to limno-terrestrial microhabitats that are disconnected from conventional surface waterbodies. In rare occasions, water films on terrestrial tropical and subtropical vegetation may also harbour specialised cladocerans. Bryospilus Frey, 1980 (Chydoridae) is the only genus within the class Branchiopoda that is specialised to living almost exclusively in water-saturated terrestrial moss patches, leaf litter, and phytotelms. The remarkable waterflea lineage, which has a suite of highly unusual characters within the family, has been found in terrestrial habitats in rainforests of West Africa, South and Central America, and New Zealand. We discovered a new moss-inhabiting chydorid from western India, Bryospilus (Indobryospilus) bharaticus n. sp., the first representative of the genus from the Oriental Region. Its morphology and behaviour are highly unusual for a species of Bryospilus. In comparison to its congeners, the new species can swim and it has significantly less oligomerisation, with three terminal setae on the antennal endopod instead of two and seven exopod setae on the third limb instead of six, among other features. We define a new subgenus Indobryospilus nov. and we amend the genus Bryospilus. The new species is a living evolutionary connection, characterised by a phenotype which provides us with new clues about evolutionary transitions in the only terrestrial branchiopod genus. Our results are informative beyond Cladocera, as the morphology of this species provides insights about the evolution and parallelisms of aquatic crustaceans that have specialised in limno-terrestrial habitats. We revisit the morphology of the genus, the disjunct biogeographical pattern with a potential ancient signature, and discuss the functional adaptations of these cladocerans to life on land, as well as convergences with subterranean lineages. A new key to the world species of Bryospilus species is included.

Synergistic effects of zinc and cadmium on phytoremediation potential of Christmas moss (Vesicularia montagnei)

The hyperaccumulation potential of zinc (Zn) and cadmium (Cd) and their synergistic effects were examined in relation to Christmas moss (Vesicularia montagnei (Bél) Broth., Hypnaceae), an aquatic and terrestrial moss, dosed with Cd (Cd1 and Cd2), Zn (Zn1 and Zn2) and combined Zn and Cd (Cd1Zn1 and Cd2Zn2). Zinc promoted plant growth and development, particularly in the highest Zn and combined Zn/Cd treatments (Zn2 and Cd2Zn2). The Zn treatment resulted in substantial moss chlorophyll content and highest percentage relative growth rate in biomass value (0.23 mg L−1 and 106.8%, respectively); however, the Cd2Zn2 treatment achieved maximal production of chlorophyll a and total chlorophyll (0.29 and 0.51 mg L−1, respectively) due to synergistic effects. These findings suggest that Christmas moss is a highly metal-tolerant and adaptable bryophyte species. Zinc was essential for reducing the detrimental effects of Cd while simultaneously promoting moss growth and biomass development. Furthermore, Christmas moss exhibited hyperaccumulation potential for Cd and Zn in the Cd2Zn2 and Zn alone treatments, as evidenced by highest Cd and Zn values in gametophores (1002 and 18,596 mg per colony volume, respectively). Using energy dispersive X-ray fluorescence (EDXRF) spectrometry, atomic percentages of element concentrations in moss gametophores in the Zn2, Cd2 and combined Zn/Cd treatments were generally in the order: K > Ca > P > Zn > Cd. When comparing the atomic percentages of Zn and Cd in gametophores, it is likely that the higher atomic percentage of Zn was because this element is essential for plant growth and development.

Terrestrial mosses as a substrate and potential host for cyanobacteria, green algae and diatoms

Most studies of terrestrial bryophytes as natural substrates for photosynthetic microorganisms have been performed in the polar regions, where bryophytes are an important part of the ecosystem. As they remain green throughout the year, bryophytes may also be an ideal substrate for epiphytic organisms in temperate regions. The present study investigated the colonization potential and diversity of microalgae on selected plant species in riparian forest and spruce monoculture in a temperate region. It examines whether the presence of algae is related to substrate humidity, the micromorphology of gametophyte or the seasonal availability of substrate. The taxonomic diversity of algae was studied. Cyanobacteria and green algae were cultured on BG-11 agar medium, while diatoms were identified in permanent diatomaceous slides. The alpha- and beta-diversity indices were calculated, and the communities were compared using Bray-Curtis distances and multidimensional correspondence analyses. Our findings indicate that the largest number of alga species were diatoms; however, their presence was only observed in riparian forest and was associated with high humidity. Both aerophilic and freshwater taxa were noted, the latter carried by water from nearby aquatic ecosystem. Green algae were present in both phytocoenoses and humidity appears to have no substantial effect on the degree of colonization; their diversity was low and the group consisted of terrestrial taxa. In two bryophytes growing at the highest humidity, cyanobacteria were only identified in culture. The key factor influencing the degree of microalgae colonization was the humidity of the substrate, which was related to the distance from water.

Preliminary Studies on the Invertebrate Microfauna Associated with A Terrestrial Moss, Hyophila sp. in Urban Areas of Chennai, Tamil Nadu, India

Bryophytes provide microhabitat, optimal temperature condition, and act as reliable nutrient sources for invertebrate fauna. In the present study, microscopic analysis of the invertebrate micro fauna associated with a terrestrial moss, Hyophila sp. was examined. The work was conducted for a period of six months from october to march and the invertebrate microfauna was recorded for two different seasons (october-december and january – march). It was found that protozoans, rotifers, nematodes, eggs or cysts and certain larvae were present throughout the study period. However, their proportions were significantly altered during the two different seasons. Metabolically active animals were seen in higher numbers during monsoon period (October-december) compared to higher number of eggs and cysts during drier months (January –march). This study highlights the different microfaunal population associated with the urban moss, Hyophila sp. and adds to the growing pool of literature on moss- microfaunal association.

What potential do mosses have as biomonitors of POPs? A comparative study of hexachlorocyclohexane sorption

Persistent organic pollutants (POPs) pose a significant global threat to human health and the environment, and require continuous monitoring due to their ability to migrate long distances. Active biomonitoring using cloned mosses is an inexpensive but underexplored method to assess POPs, mainly due to the poor understanding of the loading mechanisms of these pollutants in mosses. In this work, Fontinalis antipyretica (aquatic moss) and Sphagnum palustre (terrestrial moss) were evaluated as potential biomonitors of hexachlorocyclohexanes (HCHs: α-, β-, γ-, δ-HCH), crucial POPs. Moss clones, grown in photobioreactors and subsequently oven-dried, were used. Their lipid composition and distribution were characterized through molecular and histochemical studies. Adsorption experiments were carried out in the aqueous phase using the repeated additions method and in the gas phase using an active air sampling technique based on solid-phase extraction, a pioneering approach in moss research. F. antipyretica exhibited greater lipid content in the walls of most cells and higher adsorption capacity for all HCH isomers in both gaseous and liquid environments. These findings highlight the need for further investigation of POP loading mechanisms in mosses and open the door to explore other species based on their lipid content.

Moss as a passive biomonitoring tool for the atmospheric deposition and spatial distribution pattern of toxic metals in an industrial city.

Anthropogenic pollution impacts human and environmental health, climate change, and air quality. Karabük, an industrial area from the Black Sea Region in northern Türkiye, is vulnerable to environmental pollution, particularly soil and air. In this research on methodological aspects, we analyzed the concentrations of six potential toxic metals in the atmospheric deposition of the city using the passive method of moss biomonitoring. The ground-growing terrestrial moss, Hypnum cupressiforme Hedw., was collected during the dry season of August 2023 at 20 urban points. The concentrations of Cr, Cu, Cd, Ni, Pb, and Co were determined in mosses by the ICP-MS method. Descriptive statistical analysis was employed to evaluate the status and variance in the spatial distribution of the studied metals, and multivariate analysis, Pearson correlation, and cluster analysis were used to investigate the associations of elements and discuss the most probable sources of these elements in the study area. Cd and Co showed positive and significant inter-element correlations (r > 0.938), representing an anthropogenic association mostly present in the air particles emitted from several metal plants. The results showed substantial impacts from local industry, manufactured activity, and soil dust emissions. Steel and iron smelter plants and cement factories are the biggest emitters of trace metals in the Karabük area and the primary sources of Cr, Cd, Ni, and Co deposition.

Assessment of Atmospheric Pollution by Selected Elements and PAHs during 12-Month Active Biomonitoring of Terrestrial Mosses

Biomonitoring studies are most often used in short-term study periods to quickly obtain information on the state/quality of the environment and its pollution levels. Performing long-term surveys involves a prolonged wait for the result and is therefore not often used and is rather associated with classical air quality monitoring. The aim of this study was to evaluate atmospheric air pollution by selecting 16 elements and 16 polycyclic aromatic hydrocarbons conducted as part of a 12-month ‘moss-bag’ technique of an active biomonitoring method with the use of three moss species: Pleurozium schreberi, Sphagnum fallax, and Dicranum polysetum. All analytes were determined by inductively coupled plasma mass spectrometry (ICP-MS) and gas chromatography–mass spectrometry (GC-MS). As a result of the experiment, it was found that the concentrations of all elements increased with time of exposure. The total sum of them in D. polysetum moss was 30% and 60% more than in P. schreberi and S. fallax, respectively, which allows us to consider this species’ broader use in active biomonitoring. For PAHs analysis, the best biomonitor in time was P. schreberi, which accumulated 25% and 55% more than S. fallax and D. polysetum, respectively. In this one-year study, most organic compounds accumulated between 5 and 6 months of exposure, depending on the species. Given the low-cost nature of active biomonitoring, it should be concluded that mosses could be used in long-term monitoring of the quality of the atmospheric aerosol in terms of element and organic compound concentration in air.

First fossil record of Trichosteleum (Bryophyta: Sematophyllaceae) from mid-Miocene Zhangpu amber in Asia

The evolutionary history of terrestrial moss in Asia during the Cenozoic is poorly interpreted in largely because of very limited fossil evidence. The middle Miocene Zhangpu amber is the sole resin source of moss fossils in China, which shows a diverse moss population during the mid-Miocene Climatic Optimum. In this study, we reported the discovery of a gametophyte fragment of moss fossil in a well-preserved amber inclusion from the middle Miocene of Zhangpu, Southeast China. The observation methods involved light microscopy and synchrotron radiation–based X-ray microcomputed tomography analysis on the amber inclusions. The fossil has lanceolate leaves with involute margins, long linear laminal cells with unipapillae, well-developed and enlarged alar cells, and an absence of costae. The fossil is assigned to the extant Trichosteleum and represents the only known occurrence of a fossilized Trichosteleum member in Asia. This finding enhances our comprehension on the moss diversity within Zhangpu amber and establishes a first record of Trichosteleum in Asia.

Seasonal changes in spatial distribution of 7Be atmospheric deposition measured using terrestrial mosses

Seasonal changes in spatial distribution of 7Be atmospheric deposition measured using terrestrial mosses

Unravelling the metal uptake process in mosses: Comparison of aquatic and terrestrial species as air pollution biomonitors

Transplanted mosses have been widely shown to be excellent tools for biomonitoring air pollution; however, it is not clear how the functional groups present on their surfaces affect the uptake of metal cations. In the present study, we examined differences in trace metal accumulation in two terrestrial and one aquatic moss species, and investigated whether the differences depended on their physico-chemical characteristics. In the laboratory, we determined C, N and H contents in their tissues and obtained the ATR-FTIR spectra (to identify the presence of functional groups). We also conducted surface acid-base titrations and metal adsorption assays with Cd, Cu and Pb. In the field, we exposed transplants of each species near different air-polluting industries, and determined the mosses enrichment of Al, Cd, Co, Cr, Cu, Fe, Ni, Pb and V. Laboratory results demonstrated higher metal uptake capacity in the terrestrial mosses Sphagnum palustre and Pseudoscleropodium purum, compared to that in the aquatic moss Fontinalis antipyretica, which can be attributed to a greater abundance of acidic functional groups (i.e. negatively charged binding sites) on the surface of the terrestrial mosses. The affinity of moss for certain elements depends on the abundance and nature of surface functional groups. Accordingly, the metal concentrations generally reached higher levels in S. palustre transplants compared to the other species, except for the uptake of Hg, which was higher in F. antipyretica. However, the findings also suggest an interaction between the type of environment (terrestrial or aquatic) and the moss characteristics that may influence the abovementioned trend. Thus, irrespective of the physico-chemical characteristics, metal uptake varied depending on the environment of origin of the mosses “i.e. atmospheric or aquatic”. In other words, the findings suggest that species that accumulate more metals in terrestrial environments will accumulate lower amounts of metals in aquatic environments and vice versa.

Moss-inhabiting beetles of the West Indies (Insecta: Coleoptera)

This study is the first attempt to assess the diversity of beetles (Coleoptera) in terrestrial moss cushions on three West Indian islands (Hispaniola, Jamaica, and Puerto Rico) based on 10 years of moss sampling in 18 localities. In total 1711 adult beetles were collected. They belong to 234 species from 30 families. The most species and specimen rich families are Staphylinidae (86 morphospecies and 1195 specimens), Curculionidae (61 morphospecies and 131 specimens), and Chrysomelidae (16 morphospecies and 185 specimens). In addition to basic bryobionts feeding on moss tissues, moss cushions host a diverse fauna of mycophagous and saprophagous Coleoptera together with predaceous species of beetles. Our results suggest that community composition in moss inhabiting beetles is determined both by geographical isolation processes and, to a lesser degree, by environmental variation across altitudinal gradients. This confirms that the greater relevance of geographical isolation is a common pattern in organisms with limited dispersal ability. Beetle abundance was not significantly related to either the volume of moss or the substrate. Despite being not significant (but close to), the observed trend was to higher beetle abundance in moss cushions collected on trees than in those collected on soil/rock. This may be resulting from the greater diversity of fungi and higher number of beetle fungivores associated with tree growing moss communities.

Mythbusters: Unravelling the pollutant uptake processes in mosses for air quality biomonitoring

Terrestrial mosses have been used for more than 50 years to monitor air pollution. We argue, however, that their value as biomonitors is based on two widespread but partially erroneous assumptions concerning their morphological structure (the structural myth) and physicochemical characteristics (the physicochemical myth). The structural myth consists of the oversimplification of the moss morphological structure. The physicochemical myth recognizes their high cation exchange capacity (CEC) as the only pathway for pollutant uptake. Here, we gather and discuss the evidence demonstrating that these assumptions are misleading and focus the discussion on the aspects that make mosses good biomonitors of air pollution. First, we show that these plants (i) do have a cuticle, whose structure and composition differs among species, (ii) can have epidermal cells, that differ in shape and thickness from other cell types, (iii) have a vascular system, whose degree of development is lineage- and species-specific, and (iv) have rhizoids, that can absorb water, nutrients and pollutants. The effect of these traits in the pollutant uptake processes has been understudied in biomonitoring studies. Second, we show that mosses (i) do not concentrate as much pollutants as they could according to their high CEC, (ii) can retain large amounts of particles containing atmospheric pollutants in their surfaces, and (iii) in many contexts, the spatial structure of the concentrations of pollutants in mosses depicts the pattern expected for atmospherically deposited particles. Thus, the quality of these organisms as biomonitors of air pollution also lies in their high capacity to retain particles. We do call for more research on how moss structural and physiological traits affect pollutant uptake dynamics and recommend researchers using mosses as air quality biomonitors to face critically to inaccurate or insufficiently demonstrated assumptions in this context.

Uptake of Radionuclides by Bryophytes in the Chornobyl Exclusion Zone

The "Chernobyl nuclear disaster" released huge amounts of radionuclides, which are still detectable in plants and sediments today. Bryophytes (mosses) are primitive land plants lacking roots and protective cuticles and therefore readily accumulate multiple contaminants, including metals and radionuclides. This study quantifies 137Cs and 241Am in moss samples from the cooling pond of the power plant, the surrounding woodland and the city of Prypiat. Activity concentrations of up to 297 Bq/g (137Cs) and 0.43 Bq/g (241Am) were found. 137Cs contents were significantly higher at the cooling pond, where 241Am was not detectable. Distance to the damaged reactor, amount of original fallout, presence of vascular tissue in the stem or taxonomy were of little importance. Mosses seem to absorb radionuclides rather indiscriminately, if available. More than 30 years after the disaster, 137Cs was washed out from the very top layer of the soil, where it is no more accessible for rootless mosses but possibly for higher plants. On the other hand, 137Cs still remains solved and accessible in the cooling pond. However, 241Am remained adsorbed to the topsoil, thus accessible to terrestrial mosses, but precipitated in the sapropel of the cooling pond.

Spatial distribution and source analysis of airborne trace metal deposition using moss biomonitoring in Huai'an, China.

Terrestrial mosses are tracers for studying atmospheric trace metal deposition and pollution. Here, Al, Fe, Zn, Mn, Ba, Cu, V, Cr, Pb, Ni, Co, and Cd concentrations in mosses from Huai'an, China, were measured to investigate their contamination level, spatial distribution, and sources. The average concentration of all the metals (except Ni) was much higher than those in Albania, a "hotspot" of toxic metal contamination in Europe. The pollution degree of the metals varied significantly: moderate contamination by Al, Fe, Mn, Zn, Cr, V, and Cd; slight contamination by Ba, Cu, Ni, and Pb; and suspected contamination by Co. Based on the Nemerow index (PN), only 8% of the moss samples were graded as moderate pollution, while the remaining 92% were rated as heavy pollution, with Cd and Zn contributing the most. The potential ecological risk index (RI) indicated a moderate potential ecological risk from the metals in Huai'an, with the atmosphere most heavily polluted by Cd. Further, the positive matrix factorization (PMF) model was applied to confirm the metal contamination sources and allocate their source contributions in Huai'an mosses. The results showed that the source contributions of industrial activities related to metal smelting, textile dyestuff and agricultural activities, mining development, natural source, and coal burning and traffic emission accounted for 28.86%, 20.29%, 19.83%, 17.98%, and 13.04%, respectively.

Bioaccumulation of Trace Elements from Aqueous Solutions by Selected Terrestrial Moss Species.

The interrelationship between metal concentrations in mosses and their surroundings prompts research toward examining their accumulation properties, as it is particularly important for their usage in biomonitoring studies that use mosses. In this study, the kinetics of elemental sorption in three moss species (Pleurozium schreberi, Dicranum polysetum, and Sphagnum fallax) were investigated under laboratory conditions. Sorption from metal salt solutions was carried out under static conditions with decreasing elemental concentration. Functional groups responsible for binding metal cations to the internal structures of the mosses were also identified. It was shown that the equilibrium state was reached after about 60 min. Under the conditions of the experiment, in the first 10 min of the process, about 70.4-95.3% of metal ions were sorbed from the solution into the moss gametophytes by P. schreberi (57.1-89.0% by D. polysetum and 54.1-84.5% by S. fallax) with respect to the concentration of this analyte accumulated in the mosses at equilibrium. It can be assumed that the exposure of mosses with little contamination by heavy metals in an urbanized area under active biomonitoring will cause an increase in the concentration of these analytes in proportion to their concentration in atmospheric aerosols. In the case of P. schreberi and D. polysetum, the O-H/N-H band was enormously affected by the adsorption process. On the other hand, FTIR (Fourier transform infrared spectroscopy) analysis of S. fallax after adsorption showed slight changes for most of the bands analyzed. Based on this study, it can be concluded that mosses can be used as, for example, a biomonitor in monitoring of urban ecosystems, but also in the phytoremediation of surface waters.

Assessment about bioindicator capacity of acrocarpous moss Campylopus schmidii exposed to abandoned pyritic tailings.

Terrestrial mosses are promising species to study concerning metal deposition, absorption, and soil fertility as moss biocrusts. However, acrocarpous moss, as a kind of terrestrial mosses, has not yet been well understood, both in environmental monitoring and ecological application, especially exposed to an abandoned pyrite mining. Herein, we investigated the concentrations of different heavy metals in soil underlying acrocarpous moss Campylopus schmidii at three distances from an abandoned pyrite mine tailings (0.5, 1, 2km) by sampling analysis, as well as the accumulation properties of heavy metals in different parts of mosses and soil nutrients under intact mosses and moss-free layers. The results indicated that the soil we researched was heavily polluted by Cr, Cu, and Cd, which was 4.46, 4.18, and 1.77 times higher than the standard of risk screening values for soil environment quality in China. And there was a marked difference in the concentrations and distribution of heavy metals in mosses, with higher concentrations of Cr, Cu, Ni and Pb mainly in the ageing parts. In addition, mosses can effectively promote soil fertility. Compared with the bare soil without the moss layer, the total organic matter and total potassium concentrations of the soil covered by the intact moss layer were significantly increased, by 113.91% and 186.08% respectively. Correlation analysis indicated that similar pollution sources for Zn, Cd, Cu, and Pb, and the concentrations of these heavy metals in soil connected with the distance from the source of pollution. Overall, we expected that these findings could assess the greater potential of single native dominant moss species C.schmidii to act as biomonitors in specific pyrite mine tailings characterized by barren soil with strong acids (pH<4.0) and polymetallic pollution. Meanwhile, our results revealed may serve as a possibility reference for similar areas and is recommended for developing a vegetative cover utilizing local acrocarpous mosses to achieve greening of degraded tailings in the future, as well as environmental management and protection.

Statistical analysis of atmospheric deposition of heavy metals in Kosovo using the terrestrial mosses method

Heavy metals presence in the air in the territory of Kosovo was estimated using mosses as biomonitors. The periodic smog over the territory of Kosovo, particularly around industrial sites and cities, is a clear indication of air pollution which unavoidably will contain heavy metals, because of the nature of the industries in area. This work was carried out aming to assess the presence of heavy metals in the air, identify the most polluted sites, and the origins of pollution. Heavy metals such as Al, Cd, Cr, Cu, Fe, Ni, Pb, and Zn, were determined in 45 moss samples. Statistical analysis was performed to better explain the data. The most polluted sites appeared to be in Zveqan, Stanterg, Prapashticë, Siboc, and Lupç. The contamination factor (CF) showed that only Cu and Zn had no or almost no contamination levels over the range of moss samples with CF < 1, while Cd and Pb gave extremely high values, CF > 27. Pollution load index (PLI) also showed that only a few samples are moderately polluted 2 < PLI ≤ 3, while most of the samples appeared to be highly polluted 4 < PLI ≤ 5, and very highly polluted PLI > 5.

A new small-celled diatom from Brazil - Luticola minutissima sp. nov., with comparison to the type of the Antarctic L. neglecta Zidarova, Levkov &amp;amp; Van de Vijv

The samples for this study were collected from terrestrial mosses and lichens growing on palm tree trunks and concrete walls in the city of Rio de Janeiro, south-eastern Brazil. During the investigation on diatom diversity, a new species from the genus Luticola was found. The new species occurred individually at all sampling sites. The aim of this paper is to provide a morphological and ecological description of Luticola minutissima sp. nov. from an aerophytic environment. The species is characterized by a small valve size (5.2–16.8 μm length and 3.7–4.4 wide) and abruptly hooked proximal raphe endings (ca. 90-degree angle). Additionally for comparison, type material of the most similar species, Luticola neglecta Zidarova, Levkov &amp; Van de Vijver, was studied and new information for the ultrastructure of the latter species is provided as well.