Aquatic Biotopes Research Articles

Microplastic pollution in aquatic ecosystems: impacts on diatom communities.

In recent years, heightened concern has emerged regarding the pervasive presence of microplastics in the environment, particularly in aquatic ecosystems. This concern has prompted extensive scientific inquiry into microplastics' ecological and physiological implications, including threats to biodiversity. The robust adsorption capacity of microplastic surfaces facilitates their widespread distribution throughout aquatic ecosystems, acting also as carriers of organic pollutants. However, to comprehensively understand the broader implications of this pollution, a thorough examination of the origins, composition, and widespread distribution of microplastics within aquatic biotopes is imperative. Diatoms, unicellular photosynthetic organisms, play a pivotal role in aquatic ecosystems as primary producers, forming the base of the aquatic food web. Investigating the relationship between microplastics and diatoms, leveraging methodological advancements, holds promise in unraveling the intricate action mechanisms underlying their interactions. Such inquiry sheds light on the physiological responses elicited and provides crucial insights into the ecological dynamics within aquatic environments. This study explores the understanding of microplastic-diatom interactions, focusing on how microplastic types, sizes, and concentrations influence diatoms. Ultimately, the current study strongly advocates for transdisciplinary collaborations, such as partnerships between ecologists, materials scientists, and policymakers, as the complexity of microplastic pollution demands collective efforts to address this critical and alarming environmental issue.

Advancing Knowledge of Wetland Vegetation for Plant Diversity Conservation: The Case of Small Lakes, Ponds, and Pools in Maremma (Southern Tuscany, Central Italy)

Wetlands are among the world’s valuable ecosystems for biodiversity conservation, but they are also among the most threatened habitats, heavily impacted by human pressures and threats. The Mediterranean basin features numerous small lakes, ponds, and pools, whose number and quality are decreasing at an alarming rate, and whose biodiversity is often little or not at all known. As a better knowledge of the biotic components of these minor water bodies is necessary, with this aim a phytosociological survey campaign was carried out in southern Tuscany (central Italy), an area where little information is available on the vegetation of aquatic and palustrine biotopes. Numerous previously unknown water bodies were located and surveyed in this work, while others already known were resurveyed. These investigations allowed us to identify 28 plant communities which can be classified into seven syntaxonomic classes. A new subassociation (Ranunculo ophioglossifolii-Callitrichetum stagnalis subass. ranunculetosum peltati) is described. The identification of the site-associated Natura2000 habitats led to the recognition of five habitats of conservation interest at the national and European level. The results of these investigations will improve the knowledge of the flora and vegetation of these small but valuable natural areas, providing a basis for their conservation.

Among-population variation in sexual size dimorphism of Nepa cinerea (Heteroptera: Nepomorpha)

AbstractNepa cinerea is a common aquatic predator. It is widely distributed in various aquatic biotopes of the Palaearctic. Body size is an important trait that impacts the fitness and survival of animals and thus their evolution. Like most insects, N. cinerea males are smaller than females, but sexual size dimorphism (SSD) has not been investigated. We investigated the extent of SSD, the validity of Rensch's rule, and morphological differences between nine populations based on 51 morphological parameters. Females were found significantly and marginally significantly larger than males in all but one population. However, no difference in body length was found between the populations. Population had a significant effect on 12 traits for females and only on 5 for males, showing that females are more variable than males. Specifically, differences were found in the length of the second and third leg pairs. We did not find any support for the Rensch's rule. Nevertheless, female body size and SDI (sexual dimorphism index) were positively correlated. We suggest that fecundity selection accounts for female-biased SSD in N. cinerea.

Flourishing in Darkness: Protist Communities of Water Sites in Shulgan-Tash Cave (Southern Urals, Russia)

Karst caves, formed by the erosion of soluble carbonate rocks, provide unique ecosystems characterized by stable temperatures and high humidity. These conditions support diverse microbial communities, including wall microbial fouling, aquatic biofilms, and planktonic communities. This study discloses the taxonomic diversity of protists in aquatic biotopes of Shulgan-Tash Cave, a culturally significant site and popular tourist destination, by 18S rRNA gene metabarcoding. Our findings reveal the rich protist communities in the cave’s aquatic biotopes, with the highest diversity observed in Blue Lake at the cave entrance. In contrast, Distant Lake in the depth of the cave was inhabited by specific communities of plankton, mats, and pool fingers, which exhibited lower richness and evenness, and were adapted to extreme conditions (cold, darkness, and limited nutrients). High-rank taxa including Opisthokonta, Stramenopiles, and Rhizaria dominated all biotopes, aligning with observations from other subterranean environments. Specific communities of biotopes inside the cave featured distinct dominant taxa: amoeboid stramenopile (Synchromophyceae) and flagellates (Choanoflagellatea and Sandona) in mats; flagellates (Choanoflagellatea, Bicoecaceae, Ancyromonadida) and amoeboid protists (Filasterea) in pool fingers; flagellates (Ochromonadales, Glissomonadida, Synchromophyceae), fungi-like protists (Peronosporomycetes), and fungi (Ustilaginomycotina) in plankton. The specificity of the communities was supported by LEfSe analysis, which revealed enriched or differentially abundant protist taxa in each type of biotope. The predominance of Choanoflagellatea in the communities of cave mats and pool fingers, as well as the predominance of Synchromophyceae in the cave mats, appears to be a unique feature of Shulgan-Tash Cave. The cold-tolerant yeast Malassezia recorded in other caves was present in both plankton and biofilm communities, suggesting its resilience to low temperatures. However, no potentially harmful fungi were detected, positioning this research as a baseline for future monitoring. Our results emphasize the need for ongoing surveillance and conservation efforts to protect the fragile ecosystems of Shulgan-Tash Cave from human-induced disturbances and microbial invasions.

Distribution of selenium: A case study of the Drava, Danube and associated aquatic biotopes

This paper presents the results of the research on the overall distribution of selenium (Se) in various aquatic compartments (water, sediment, plankton and macrophytes) at six selected sites of the Croatian part of the Drava and Danube rivers, the connected floodplain lake and the melioration channel system carried out in two sampling periods (flooding in June and the drought period in September). In addition, the physicochemical water properties, plankton composition and biomass were analysed. Our study revealed low mean Se contents in sediments and water, indicating Se deficiency in the studied freshwater systems. The physicochemical environment, including Se distribution, was primarily influenced by hydrology rather than site-specific biogeochemical and morphological characteristics. The flooding period was characterised by higher Se content in water and higher transparency, nitrate and total nitrogen concentrations than drought conditions. At the river sites, sediment Se content was the highest during the flood period, while at all other sites, higher concentrations were found during the drought, reaching the maximum in the lake. Although Se concentrations were below the threshold for aquatic ecotoxicity, they increased in the following order: water (0.021–0.187 μg Se L−1) < sediments (0.005–0.352 mg Se kg−1) < macrophytes (0.010–0.413 mg Se kg−1) < plankton (0.044–0.518 mg Se kg−1) indicating its possible biomagnification at the bottom of the food chain. Species known for high Se accumulation potential dominated the biomass of the main plankton groups and the composition of the macrophyte community, which may provide a more sensitive and accurate steady-state compartment monitor for Se assessment in freshwater biotopes.

Bioaccumulation of heavy metals and petroleum hydrocarbons in the blue crab (&lt;i&gt;Callinectes sapidus&lt;/i&gt;, Rathbun 1896) from Ogu Creek in Upper Bonny Estuary, Nigeria

Prolonged industrial and artisanal discharge of petroleum refinery effluents into the Ogu Creek at the Upper Bonny estuary of the Niger Delta could pose a great threat to the aquatic biotopes. This research investigated bioaccumulation of selected heavy metals and petroleum hydrocarbons in the blue crab (Callinectes sapidus) from the creek. Crabs (N=20; average length 18±20cm; weight 150.18±0.02g) were collected with nets. Mean concentrations (mg/l) of Zn (0.044±0.01), Cd (0.002±0.00), Cr (0.001±0.00), Pb (0.001±0.00), Fe (5.82±0.29), Mn (0.001±0.00), total petroleum hydrocarbons (TPH; 40.23±2.83) and total polynuclear aromatic hydrocarbons (ΣPAHs;7.60±1.29) were lower in water than sediments (22.10±1.37, 1.98±0.04, 2.13±0.09, 4.80±0.57, 24.03±1.29, 0.04±0.01, 70.93±3.10 and 29.80±4.02mg/kg, respectively) at the impacted location. Accumulations (μg/g) in digestive tract (dtr), muscle (mus) and ovaries (ov) were as follows: Zn 10.50 (dtr), 11.00 (mus), 2.40 (ov); Cr 0.21 (dtr), 0.10 (mus), 0.04 (ov); Cd 0.01 (dtr), 0.02 (mus), 0.01 (ov); Pb 0.04 (dtr), 0.02 (mus), 0.01 (ov); Mn 0.05 (dtr), 0.03 (mus), 0.01 (ov); TPH 4.14 (dtr), 3.14 (mus), 1.20 (ov); and mononuclear aromatic hydrocarbons (MAHs=BTEX) 0.01μg/g (dtr), 0.02 μg/g (mus), 0.01 μg/g (ov). Accumulations of TPH and BTEX were significantly (p&lt;0.05) higher at the impacted location (p = 0.03 and 0.02, respectively) than reference locations. High TQ/HQ values of 1.59, 2.82 and 1.90 were recorded for Zn, TPHs and PAHs, respectively. The results raise environmental health concerns among consumers of the aquatic food in the area.

Susceptibility of some Enterobacteriaceae isolated from 4 different aquatic environments in DR Congo (Central Africa), to Amoxicillin/Clavulanic acid and some 3rd generation Cephalosporins

Little is known about the variation of the antibiotic susceptibility of different bacterial strains of the same cells species, isolated from different aquatic environments. The present study aims to evaluate the susceptibility towards some 3rd generation cephalosporins (Ceftriaxon, Ceftazidim and Cefotaxim) and Amoxicillin/Clavulanic acid, of Enterobacteriaceae strains isolated from groundwater, stream, hospital wastewater and slaughterhouse wastewater. Enterobacteria species were isolated on Mac Conkey agar, then identified using enzymatic and MALDI-TOF MS system. The antimicrobial susceptibility was carried out using the disk diffusion method. The antibiotic minimum inhibitory concentrations (MICs) were carried using the VITEK®2 system. Bacterial species mostly identified were Klebsiella pneumoniae, Escherichia coli, Salmonella typhi and Ewingelia americana. The antibiotic inhibition diameters and the MICs varied depending on the antibiotics, bacterial species and type of aquatic environment hosting the microorganism. Relatively lower MICs were recorded with Cefotaxim against different bacteria in slaughterhouse wastewater, in river water and in well water. Antibiotic resistance was noted with all strains from hospital wastewater. Significant differences (P˂0.05) amongst antibiotic inhibition diameter was noted for K. pneumoniae and S. typhi in most cases. The relative variations in the action mechanisms amongst antibiotics and the intrinsic defense potential of each bacterial strain, as well as the potential influence of the physicochemical properties of each water medium, could partly be at the origin of the relative differences observed at the phenotypic level. It seems necessary to explore the diversity, similarities and differences amongst antibiotic resistance genes in these different types of aquatic biotopes.

Environmental Consequences of the Explosion of the Kahovsky Hydroelectric Plant on Biodiversity

The purpose of this article is to determine the ecological consequences of the explosion of the Kakhovka hydroelectric plant (southern Ukraine) on the biological diversity of the region. The main research methods were: theoretical generalization and system-functional approach, analysis, synthesis, expedition method. The ecological consequences of the destruction of a hydroelectric dam are divided into two types: drainage and flooding. As a result of the flooding, 48 objects of the nature reserve fund, with a total area of 120 thousand hectares, were affected. Aquatic biotopes and biotopes characteristic of overmoistened areas were the most affected by drainage. 38 rare types of biotopes, which are under the protection of the Bern Convention, were affected by the ecological disaster; wetlands of international importance (so-called Ramsar) with an area of 33,000 hectares in the Dnipro delta and seven objects of the Emerald network. Prospects for further research are related to the study of biotope restoration after an ecological disaster.

EFFECT OF CAFFEINE ON SELECTED REPRESENTATIVES OF PHOTOTROPHIC MICROORGANISMS

Aquatic ecosystems are becoming increasingly affected by micropollutants. The survival of microbial communities and entire aquatic ecosystems depends directly on their ability to adapt to this type of pollution. One of the most common micropollutants found in water bodies, especially in the vicinity of large cities, is caffeine. This stimulant directly affects living organisms and can cause changes in the species composition of microbial communities. However, the best way to decontaminate caffeine from the environment may be through the use of microorganisms. Therefore, in this study, the effect of caffeine on selected species of cyanobacteria and algae was investigated. The following strains of cyanobacteria: Geitlerinema cf. acuminatum (CCALA 141), Chlorogloeopsis fritschii (CCALA 039), Chlorogloeopsis fritschii (CCALA 1005), and Synechococcus granulates (CCALA 187) and a eukaryotic photosynthetic flagellate Euglena gracilis (strain Z) were selected. Probit analysis determined the minimum inhibitory concentration (MIC) of caffeine for each studied species. Also, the inhibitory effect of caffeine on each tested strain was monitored in vivo. Next, the strains were microscopically observed, and the potential change in their morphology under the caffeine treatment was recorded. The reproduction rate of all species in the study were moderately inhibited by caffeine, but during the cultivation, they were able to grow in comparison with the control sets. The most sensitive species was Geitlerinema cf. acuminatum (CCALA 141). The study also showed a significant effect of caffeine on morphology changes in the strains under investigation. Caffeine at low concentrations also showed a stimulating effect on the growth of the studied species. This may lead to their improved competence potential within microbial communities in the aquatic biotopes.

Enchelyothrix muria n. gen, n. sp., (Ciliophora, Litostomatea, Spathidiida), an extreme halotroph spathidiid from Maharloo Lake, Iran

Although free-living ciliated protists (Ciliophora) commonly inhabit aquatic and terrestrial biotopes of mild to moderate salinity (PSS-practical salinity scale S = 10–150), very few have adapted to life at more extreme salinities (>150 to saturation). Such extreme halophiles or halotrophs are of interest from the standpoints of evolution, cell physiology, ecology, and even astrobiology. In this work, we present the morphology, 18S rRNA gene sequence, and phylogenetic analysis of a novel spathidiid ciliate (Ciliophora, Litosatomatea) that thrives in saturated brines of Maharloo Lake, Iran. Based on its unique combination of morphologic features, its molecular characterization, and its unusual ecology, it is assigned to a newly erected monotypic genus incertae sedis in order Spathidiida. The new species differs from other spathidiids by: a cell with a very short acutely pointed tail, the absence of a circumoral kinety with, instead, inclined, interrupted circumoral kinetofragments at the anterior end of somatic kineties and brush rows abutting the oral bulge, the absence of a contractile vacuole, a heteromorphic dorsal brush comprising five or six rows, and an extreme (at or near saturation) hypersaline habitat. We briefly discuss the persistent uncertainties regarding the phylogenetic relationships within the order Spathidiida.

Current distribution and modeling of potential distribution ofElodea nuttallii(Planch.) H. St. John at the territory of Ukraine and Europe

AbstractElodea nuttallii(Planch.) H. St. John – an invasive species that actively expands the boundaries of its secondary range. This work presents the current and predicted future distribution ofE. nuttalliiin Europe. The spread of the species is observed in northern areas with a mild oceanic climate (with mild winters and cool, rainy summers) formed by Atlantic cyclones.E. nuttalliioccurs in aquatic biotopes throughout the temperate climatic zone and partially occurs in the subtropical. It was established that the most important factors in determining the possibility of a plant’s spread are the amount of precipitation in the driest month, the minimum temperature of the coldest month, and altitude above the sea level. According to the data collected, the species is at its ecological optimum in most of Europe. Most of the changes expected in the next 100 years will take place in the next 30–40 years.

Антропогенные факторы заболеваний и гибели атлантических лососей (Salmo salar L.)

The present review examines the long-term trend of declining populations of "wild" Atlantic salmon in most European coun-tries and north-western regions of Russia, due to intensive fishing, poaching, anthropogenic impact on marine waters and freshwa-ter river systems, logging, numerous dams and hydroelectric power plants on spawning rivers, destruction of aquatic biotopes and bottom biocenoses. Deep depression of the majority of Atlantic salmon populations has been observed in the Arctic fishing re-gions of the Russian Federation for more than 30 years, which has led to a decrease in average annual catches by more than 20 times over half a century. Since 2015, the Federal Center for Animal Health has been conducting research to identify the causes of viral and bacterial etiology diseases and the death of Atlantic salmon populations going to spawn in the rivers of the Kola Pen-insula. Currently, in the course of research, the causes of disease and death of Atlantic salmon have not been established. This worries residents and the leadership of the Murmansk region, the scientific community, the Rosselkhoznadzor, the Ministry of Natural Resources and Ecology of Russia. Changes in the adaptive properties of fish, physiology, in the digestive system and eti-ology – the slaughter and death of Atlantic salmon in an aquatic environment contaminated with heavy metals, petro-hydrocarbons and other pollutants are considered through anthropogenic factors of influence. In the course of further compre-hensive studies, the establishment of the causes of diseases and death of salmon will allow to develop a system of measures and recommendations for the elimination of diseases and death of Atlantic salmon in the rivers of the Kola Peninsula, to begin the restoration of salmon populations.

How an Ecological Race Is Forming: Morphological and Genetic Disparity among Thermal and Non-Thermal Populations of Aquatic Lymnaeid Snails (Gastropoda: Lymnaeidae)

Hot (geothermal) pools and streams, a specific type of aquatic biotopes having almost worldwide distribution, maintain rich faunas of animals belonging to various taxa. Snails (Gastropoda) represent one of such groups, which form populations in geothermal waterbodies of all continents. Some freshwater snail species produce morphologically distinct hot-water populations, whose rank is often debated (full species or thermal ‘ecotype’, or ‘race’). In this study, we used six species of pond snails (family Lymnaeidae) to investigate the morphological and genetic consequences of infiltration of freshwater snails into geothermal habitats. In particular, we aimed at studying the changes in shell shape and proportions as well as the formation of unique hot-water haplotypes and the occurrence of the latter beyond geothermal waterbodies. All six species studied demonstrate diminutive body size in hot sites accompanied, in four species, by apparent alterations in shell proportions. A phenomenon of phenotypic ‘juvenilization’, when adult and able to reproduce individuals demonstrate shell proportions characteristic for full-grown individuals living under ‘normal’ conditions, is described. Unique ‘thermal’ haplotypes, not found beyond the geothermal sites, were normally restricted to a single locality, and no signs of frequent ‘travels’ of snails from one thermal habitat to another are seen. In the vast majority of cases, these exclusive haplotypes are separated from their ancestors by only a few (1–3) mutational steps, which may indicate their relatively recent origin. We are inclined to relate both size reduction and ‘juvenilization’ to the life-cycle re-adjustment following the penetration of lymnaeids to thermal habitats. The ecological (‘thermal’) intraspecific races of different species, forming in geothermal habitats, exhibit, to a great extent, evolutionary predictability (=convergent evolution; =parallelisms). The dilemma ‘ecological race vs. young species’ in application to the taxonomy of these hot-water populations is briefly discussed.

Field studies in small streams of the Atlantic Forest of southern subtropical Brazil reveal two new interstitial microcambevine catfishes of the genus Listrura (Siluriformes: Trichomycteridae)

ABSTRACT A great diversity of small fish species inhabiting shallow aquatic biotopes of the South American Atlantic Forest have been reported in recent years, but records of interstitial catfishes of the genus Listrura for the southern subtropical Brazilian region are still rare. During field inventories in this region, two new species were collected, which are herein described. The new species are distinguished from congeners by a combination of morphological characters, including caudal peduncle morphology, number of vertebrae, relative position of fins, and bone morphology. The findings here described indicate that the scarcity of records of Listrura for the subtropical Atlantic Forest is probably due to the absence of collecting efforts in specialised biotopes, since species of Listrura are leaf litter dwellers. Both new species are probably more closely related to L. depinnai than to other congeners as all three uniquely possess an expanded skin fold supporting the procurrent caudal-fin rays, making the caudal peduncle deeper than the body region anterior to the dorsal and anal fins. However, only one of the new species shares with L. depinnai the presence of a process on the dorsal surface of the autopalatine articular facet for the mesethmoid, a condition not occurring in any other congener. The two new species are easily distinguished from L. depinnai by the absence of a dorsal fin in the latter species. http://www.zoobank.org/urn:lsid:zoobank.org:pub:F68F2A3E-B5F7-418E-BFA6-EA6752BAB543 http://www.zoobank.org/urn:lsid:zoobank.org:pub:F703D95A-0F7E-4261-8B97-5EAAAD9BD698

Multi-layered nanofiber membranes: Preparation, characterization, and application in wastewater treatment

Over the last few decades, micropollutants have been found in the natural surface water, and their presence poses a series of risks to living organisms in the aquatic biotope. Nanofiber membranes have been shown as a new strategy for separating micron-size pollutants due to their tight pore size and high water permeability. Here, a high-efficient multi-layered nanofiber membrane with improved mechanical strength was prepared using the lamination technique. First, polyamide 6 (PA6), polyacrylonitrile (PAN), and polyvinylidene fluoride (PVDF) nanofibers webs were selected. Then nanofibers were laminated on support under various temperatures. Prepared membranes were characterized using SEM, contact angle, pore size, and air permeability tests. The significance of lamination condition on membrane structure was investigated experimentally and statically. The membranes were examined for the treatment of synthetic micropollutants. According to the results, PAN and PA6 nanofiber membranes exhibited high water permeability (over 3000 L/(m2hbar)) under low pressure, whereas PVDF membranes showed zero permeability. Besides, the prepared nanofiber membranes could separate micropollutants from water with up to 99.91% separation efficiency. Prepared nanofiber membranes hold great promise for practical applications in environmental remediation.

Phytoplankton Diversity of a Demineralized Urban Wetland of Meghalaya State of Northeast India: The Spatio-temporal Variations and the Role of Abiotic Factors

The authors analyze phytoplankton diversity of a small urban wetland of Meghalaya to assess biodiversity and limnology interest of small water bodies. This “slightly acidic-circumneutral, demineralized and soft water” subtropical wetland reveals diverse phytoplankton (64 species), indicates high desmid richness and highlights the speciose littoral constellations of up to 55-58 species per sample. Phytoplankton comprises dominant quantitative component of net plankton and registers Charophyta dominance; Chlorophyta &gt; Bacillariophyta &gt; Dinozoa &gt; Chrysophyta &gt; Cyanobacteria depict sub-dominance, and Euglenozoa and Cryptophyta show poor abundance at the littoral and semi-limnetic regions. The richness of phytoplankton and abundance of phytoplankton, Charophyta, Chlorophyta, Dinozoa, Chrysophyta and Cyanobacteria follow bimodal spatio-temporal variations. Closterium, Cosmarium, Staurastrum, Micrasterias, Netrium, Staurodesmus and Scenedesmus are notable genera, and 14 species collectively influence phytoplankton abundance. Phytoplankton registers high species diversity, lower dominance and high evenness. Amongst 15 abiotic factors, only the rainfall and sulphate exert notable influence individually, while the canonical correspondence analysis registers lower cumulative influence of the selected 10 factors on the littoral and semi-limnetic phytoplankton assemblages. This study merits interest for neglected biodiversity and ecology of small aquatic biotopes of India and urban wetlands in particular.

ВЗАИМОДЕЙСТВИЕ ПАРАЗИТОВ И БАКТЕРИЙ В ОРГАНИЗМЕ ХОЗЯИНА

Many spercies of bacteria are natural endosymbiont of animals, including invertebrates, both from aquatic and terrestrial biotopes. Endosymbionts play an important role in preserving the vital activity of bacteria. This article summarizes the data on the physiological relationship of helminths of endosymbiotic bacteria, and also presents the role of the latter in the vital activity of the parasite. Key words: endosymbiont, еndosymbiotic bacteria, coinfection

Diuron environmental levels effects on marine nematodes: Assessment of ecological indices, taxonomic diversity, and functional traits

Coastal marine systems are the most sensitive zones to emerging pollutants. The present study aims to investigate the effect of Diuron on the meiofaunal assemblages, collected from the Bizerte channel (Tunisia). Microcosm experiments were set up using four increasing Diuron concentrations [D1 (10 ng g−1 dry weight (DW)), D2 (50 ng g−1 DW), D3 (250 ng g−1 DW) and (1250 ng g−1 DW)] compared to non-contaminated sediments (controls) and all plots were incubated for 30 days. Our results show that Diuron-supplemented sediments provoked the significant decrease of meiofaunal abundance as well as a change in nematodes' diversity and structure composition. All univariate indices, as well as the cumulative k-dominance, were lower in the Diuron than the control plot. Additionally, the ordination of treatments according to the two-dimensional nMDS plots analysis showed a clear structural separation of the Diuron treated replicates from the controls based on the functional groups lists. These current data emphasize the utility of the use of biological traits in the detection of disturbances in the aquatic biotope.

Responses to Ecopollutants and Pathogenization Risks of Saprotrophic Rhodococcus Species.

Under conditions of increasing environmental pollution, true saprophytes are capable of changing their survival strategies and demonstrating certain pathogenicity factors. Actinobacteria of the genus Rhodococcus, typical soil and aquatic biotope inhabitants, are characterized by high ecological plasticity and a wide range of oxidized organic substrates, including hydrocarbons and their derivatives. Their cell adaptations, such as the ability of adhering and colonizing surfaces, a complex life cycle, formation of resting cells and capsule-like structures, diauxotrophy, and a rigid cell wall, developed against the negative effects of anthropogenic pollutants are discussed and the risks of possible pathogenization of free-living saprotrophic Rhodococcus species are proposed. Due to universal adaptation features, Rhodococcus species are among the candidates, if further anthropogenic pressure increases, to move into the group of potentially pathogenic organisms with “unprofessional” parasitism, and to join an expanding list of infectious agents as facultative or occasional parasites.

Integrative Taxonomic, Ecological and Genotyping Study of Charophyte Populations from the Egyptian Western-Desert Oases and Sinai Peninsula.

Present-day information available on the charophyte macroalgae in Egypt, including their phylogenetic affinities, remains largely incomplete. In this study, nine charophyte populations were collected from different aquatic biotopes across the Egyptian Western-Desert Oases and Sinai Peninsula. All populations were investigated using an integrative polyphasic approach including phylogenetic analyses inferred from the chloroplast-encoded gene (rbcL) and the internal transcribed spacer (ITS1) regions, in parallel with morphotaxonomic assignment, ultrastructure of the oospore walls, and autecology. The specimens identified belonged to the genera Chara, Nitella, and Tolypella, with predominance of the first genus to which five species were assigned though they presented some interesting aberrant taxonomic features: C. aspera, C. contraria, C. globata, C. tomentosa, and C. vulgaris. Based on our integrative study, the globally rare species C. globata was reported for the second time for the whole African continent. The genus Nitella was only represented by N. flagellifera, and based on the available literature, it is a new record for North Africa. Noteworthy, an interesting Tolypella sp., morphologically very similar to T. glomerata, was collected and characterized and finally designated with the working name ‘Tolypella sp. PBA–1704 from a desert, freshwater wetland’, mainly based on its concatenated rbcL+ITS1 phylogenetic position. This study not only improved our understanding on the diversity, biogeography and autecological preferences of charophytes in Egypt, but it also broadened our knowledge on this vulnerable algal group in North Africa, emphasizing the need of more in-depth research work in the future, particularly in the less–impacted desert habitats.