Halophilic Species Research Articles

Large-scale heterogeneity gradient drives the structure and biodiversity of branchiopod (Anostraca, Cladocera) egg-banks in the Nebraska Sandhills wetlands, USA

Abstract Branchiopods use resting eggs to maintain permanent populations in temporally dynamic environments as well as for dispersing to neighboring habitat patches. We used a large-scale longitudinal salinity gradient that overlays the Nebraska Sandhills, USA to determine how changes in metacommunity environmental heterogeneity influences species composition and biodiversity of branchiopod egg banks from freshwater and saline temporary wetlands. We sampled the egg banks of 54 wetlands from three metacommunities across the Nebraska Sandhills (eastern, central, and western) in which the relative abundance and salinity of saline wetlands increased westwards. Salinity had a strong effect on structuring the egg-bank metacommunities with a clear shift in species composition and species richness from the eastern to western metacommunities. Egg-bank alpha richness of the freshwater wetlands and metacommunity gamma richness declined westwards as the abundance of freshwater wetlands decreased relative to the saline wetlands. The low-salinity wetlands represented an intermediate stage between the freshwater and high-salinity wetlands, overlapping in species composition with both habitat types and supporting similar numbers of species as freshwater wetlands. High-salinity wetlands had the lowest alpha richness with only halotolerant and halophilic species.

Environmental conditions play a key role in controlling the composition and diversity of Colombian biocrust microbiomes.

Drylands soils worldwide are naturally colonized by microbial communities known as biocrusts. These soil microbiomes render important ecosystem services associated with soil fertility, water holding capacity, and stability to the areas they cover. Because of the importance of biocrusts in the global cycling of nutrients, there is a growing interest in describing the many microbial configurations these communities display worldwide. However, comprehensive 16S rRNA genes surveys of biocrust communities do not exist for much of the planet: for example, in the continents of South America and the northern part of Africa. The absence of a global understanding of biocrust biodiversity has lead us to assign a general importance to community members that may, in fact, be regional. Here we report for the first time the presence of biocrusts in Colombia (South America) through 16S rRNA genes surveys across an arid, a semi-arid and a dry subtropical region within the country. Our results constitute the first glance of the Bacterial/Archaeal communities associated with South American biocrust microbiomes. Communities where cyanobacteria other than Microcoleus vaginatus prevail, despite the latter being considered a key species elsewhere, illustrate differentiable results in these surveys. We also find that the coastal biocrust communities in Colombia include halo-tolerant and halophilic species, and that niche preference of some nitrogen fixing organisms deviate from previously described global trends. In addition, we identified a high proportion (ranging from 5 to 70%, in average) of cyanobacterial sequences that did not match any formally described cyanobacterial species. Our investigation of Colombian biocrusts points to highly diverse communities with climatic regions controlling taxonomic configurations. They also highlight an extensive local diversity to be discovered which is central to better design management and restoration strategies for drylands soils currently undergoing disturbances due to land use and global warming. Finally, this field study highlights the need for an improved mechanistic understanding of the response of key biocrust community members to changes in moisture and temperature.

Metagenomic profiling of halites from the Atacama Desert: an extreme environment with natural perchlorate does not promote high diversity of perchlorate reducing microorganisms.

We surveyed the presence of perchlorate-reducing microorganisms in available metagenomic data of halite environments from the Atacama Desert, an extreme environment characterized by high perchlorate concentrations, intense ultraviolet radiation, saline and oxidizing soils, and severe desiccation. While the presence of perchlorate might suggest a broad community of perchlorate reducers or a high abundance of a dominant taxa, our search reveals a scarce presence. In fact, we identified only one halophilic species, Salinibacter sp003022435, carrying the pcrA and pcrC genes, represented in low abundance. Moreover, we also discovered some napA genes and organisms carrying the nitrate reductase nasB gene, which hints at the possibility of cryptic perchlorate reduction occurring in these ecosystems. Our findings contribute with the knowledge of perchlorate reduction metabolism potentially occurring in halites from Atacama Desert and point towards promising future research into the perchlorate-reducing mechanism in Salinibacter, a common halophilic bacterium found in hypersaline ecosystems, whose metabolic potential remains largely unknown.

Late Holocene decoupling of lake and vegetation ecosystem in response to centennial-millennial climatic changes in arid Central Asia: A case study from Aibi Lake of western Junggar Basin

Central Asian lakes are crucial for sustaining fragile oasis ecosystems in arid regions. Understanding the response of ecosystems in these lake basins to climate change is essential for predicting future variations in these ecosystems. Aibi Lake is a notable terminal lake in arid Central Asia. In this study, a 95 cm lacustrine sediment core was drilled from Aibi Lake to investigate the response of lacustrine and terrestrial ecosystems in the lake basin to climate change over the past 3200 years. Accelerator mass spectrometry (AMS) 14C dating and multi-proxy analyses of diatoms, pollen, grain size, total organic content (TOC), total nitrogen (TN), and total hydrogen (TH) are applied to the sediment core. The grain size and geochemical results show that the lake experienced elevated levels and improved productivity and nutrition during the periods of 708–181 BCE, 0–740 CE, and 1428–1900 CE. The periods align with the Roman Warm Period, Dark Age Cold Period, and Little Ice Age, respectively. For the past 3200 years, benthic diatoms have consistently been the dominant species in the lake. During the climatic transition periods of the Dark Age Cold Period, Medieval Warm Period, and Little Ice Age, there were significant changes in the abundance and survival of certain species of diatoms. Specifically, the halophilic species (Nitzschia dissipata and Nitzschia hungarica), basophilic species (Synedra acus), and the nutrition level-relevant species (Navicula menisculus) experienced notable shifts. These changes ultimately resulted in a noticeable alteration in the structure and function of the diatom community. Over the past 3200 years, the lake ecosystem has undergone three noticeable regime shifts. In contrast, the vegetation in the lake catchment has remained relatively stable, primarily consisting of desert steppe. These results suggest that aquatic ecosystems in arid central Asia are more susceptible and exhibit more rapid responses to climate change compared to terrestrial vegetation.

Screening local marine habitats suggests a novel strain Bacillus subtilis MZ1 as a potential fatty acid producer

Within this academic research article, a bacterium isolated from a marine soil environment near the Mediterranean Sea is observed to possess the potential for producing various fatty acids, particularly n-caproic and oleic acids, as evidenced by FAME profiling. Furthermore, the introduction of glucose into the growth medium enhances the production of caprylic acid rather than caproic acid. The 16S rDNA sequencing suggested that the MZ1 strain belongs to Bacillus subtilis and is closely related to many halophilic species. FAME profiling reveals that the isolated MZ1 is competent in the total production of fatty acids compared to other marine bacterial candidates. Furthermore, the results indicate that MZ1 is efficient in the production of many other fatty acids. This exploration suggests that the marine bacterium Bacillus subtilisMZ1 can be used for the synthesis of fatty acids, which could be valuable for biodiesel production and other applications.

Formation of saline soils in the dry steppe landscapes of the Western Manych Valley on different forms of microrelief

The results of studying the physical and chemical characteristics of dry-steppe saline soils of the Western Manych valley, confined to different forms of microrelief, are presented. The soil cover of the studied territory is characterized by pronounced complexity due to the interrelation of natural and anthropogenic factors. It was revealed that chestnut saline soils and chestnut saline soils are mainly formed on micro-slopes and micro-elevations, and typical hydromorphic salt marshes are formed in saucer-shaped depressions. The soil profile has both common features (the presence of a saline horizon, a heavy loamy granulometric composition, etc.) and differences (the depth of formation of a saline horizon, the degree and chemistry of salinity, the boundaries of boiling of carbonates, the occurrence of gypsum and iron oxide forms, etc.). All saline horizons have increased density values (1.43-1.64 g /cm3), reduced humus content (no more than 2.0%) compared to the upper horizons. Geobotanical studies have shown that specific vegetation, represented by xerophilous and halophilic species, is formed on micro-slopes and micro-elevations during the development of the saline process. Various meadow and halophyte communities are formed in micro-depressions.

Morphological and genetic identification of Halophila species and a new distribution record of Halophila nipponica at the Tanjung Adang Laut shoal, Johor, Malaysia.

The Halophila species exhibit complex characteristics due to their high degree of variation across different bioregions. This study delves into the intricate characteristics of Halophila species in the Tanjung Adang Laut shoal, Johor, Malaysia, and offers valuable insights through morphological and genetic evidence. Employing internal transcribed sequences (ITS), we investigated the phylogeny of Halophila species, revealing distinct clades for H. ovalis, H. major, H. spinulosa, and the newly recorded H. nipponica. Notably, H. nipponica from the Tanjung Adang Laut shoal formed a conspecific relationship with its counterparts from Japan and Korea (98.3-98.5% similarity; 5-11 bp differences). Morphologically, distinguishing features, including the ratio of the half-lamina width (1:4.76-6.13 mm) and cross-vein count (4-7 pairs), supported the identification of H. nipponica. Genetic distance analyses revealed differences between H. nipponica, H. ovalis, and H. major, indicating haplotype diversity. Geographical variations were evident, as H. nipponica presented unique haplotypes (H24) in its clade. The 47 haplotypes network identified significant mutation sites, providing a comprehensive understanding of genetic and morphological distinctions. In conclusion, this study highlights the intricate characteristics and phylogeny of Halophila species in the Tanjung Adang Laut shoal, Johor, and provides valuable insights into their genetic and morphological diversity.

Species diversity of xerophilic Aspergillus and Penicillium in marine surface waters revealed by isolation using osmophilic medium.

The species diversity of xerophilic and halophilic fungi distributed in marine surface water was studied at four local sites located in two geographically distant regions in Japan. At each site, 5-10 samples were collected and isolated using an osmophilic medium. Species identification was conducted based on nucleotide sequence of calmodulin or β -tubulin and morphological characteristics for Aspergillus, Penicillium, and Talaromyces, and on the sequences of rRNA internal transcribed spacer for the other taxa. Overall, 231 strains were isolated from all sites and classified into 85 species belonged to 12 orders and 33 genera. The isolates that showed better mycelial growth than the control（no NaCl added) in the halotolerance test were defined as halophilic fungi, and only 22 species（10 Aspergillus species and 12 Penicillium species) were halophilic. Comparison of the halophilic fungal flora of the two regions revealed that four species common to both regions were isolated for Aspergillus, but no such species were isolated for Penicillium. Given that 15 halophilic species（10 Aspergillus and 5 Penicillium species) are known to be xerophilic species distributed in indoor environments, it can be inferred that indoor xerophilic species are likely to be widely distributed in marine surface water.

Species Diversity of Zooplankton of Small Steppe Lakes of the Northern Part of Kazakhstan

The inland waters of Northern Kazakhstan are important components of the ecosystems of this region and have unique characteristics. Endorheic steppe lakes are important ecosystems with significant ecological value. They play an important role in maintaining biodiversity, they provide water resources for living organisms, they serve as breeding and migration sites for various animal species, and their zooplankton communities have a key role in the trophic web of these waters. Therefore, the purpose of this work is to study the diversity of zooplankton communities in some small steppe lakes in the northern part of Kazakhstan (Pavlodar, Kostanay, North Kazakhstan, and Akmola regions), which have different environmental conditions. Sampling to study the species diversity of zooplankton in the steppe water bodies of Northern Kazakhstan was carried out from 13 areas, 12 of which are plain lakes, and 1 of which is a reservoir, and sampling was performed in 2021 and 2022 during in the spring, summer, and autumn periods. Within the research period of 2021–2022, between 6 and 36 species of zooplankton were found in small steppe lakes. A total of 92 taxa were found. Rotifers (46 taxa) were found to have the richest number of species representatives. Cladocera were represented by 21 taxa, and Copepods by 25 taxa. All studied steppe lakes in the northern part of Kazakhstan are characterized by high specificity in terms of taxonomic composition, since the similarity indices did not exceed 0.632. According to cluster analysis, the studied samples of water bodies are divided into five clusters, in which lakes with a relatively similar taxonomic composition are combined. The halophile species (e.g., Arctodiaptomus salinarus) indicate water salinization. Our results confirm the applicability of the use of zooplankton in assessing water quality and the current ecological state of aquatic ecosystems.

Taxonomic Composition and Salinity Tolerance of Macrozoobenthos in Small Rivers of the Southern Arid Zone of the East European Plain.

This study investigated the species composition, distribution, and salinity tolerance of macrozoobenthos in 17 small rivers in the southern arid region of the East European Plain, which are characterized by a small channel gradient, slow-flowing or stagnant water bodies, and a wide range of water salinity, varying between 0.18 and 30 g L-1. In total, 156 taxa were found, among which 66 were Diptera species. The study revealed that the formation of benthic communities in the rivers is influenced by natural factors of the catchment basins, including the flat landscape with sparsely developed relief differentiation, climate aridity, and the widespread occurrence of saline soils and groundwater, largely related to the sedimentation of the ancient Caspian Sea and modern climate changes. These conditions are favorable for the occurrence of lacustrine macrozoobenthic species in freshwater, euryhaline, and halophilic ecological groups. The investigation revealed a decrease in species richness in response to an increase in water salinity. The five identified halophilic species Tanytarsus kharaensis, Glyptotendipes salinus, Cricotopus salinophilus, Chironomus salinarius, and Palpomyia schmidti can be used as indicators of river ecosystem salinization.

Succession and assembly mechanisms of seawater prokaryotic communities along an extremely wide salinity gradient.

Salinity is an important environmental factor in microbial ecology for affecting the microbial communities in diverse environments. Understanding the salinity adaptation mechanisms of a microbial community is a significant issue, while most previous studies only covered a narrow salinity range. Here, variations in seawater prokaryotic communities during the whole salt drying progression (salinity from 3% to 25%) were investigated. According to high-throughput sequencing results, the diversity, composition, and function of seawater prokaryotic communities varied significantly along the salinity gradient, expressing as decreased diversity, enrichment of some halophilic archaea, and powerful nitrate reduction in samples with high salt concentrations. More importantly, a sudden and dramatic alteration of prokaryotic communities was observed when salinity reached 16%, which was recognized as the change point. Combined with the results of network analysis, we found the increasing of complexity but decreasing of stability in prokaryotic communities when salinity exceeded the change point. Moreover, prokaryotic communities became more deterministic when salinity exceeded the change point due to the niche adaptation of halophilic species. Our study showed that substantial variations in seawater prokaryotic communities along an extremely wide salinity gradient, and also explored the underlying mechanisms regulating these changes.

Larva morphology of shore flies <i>Ephydra riparia</i> and <i>Paracoenia fumosa</i> (Diptera: Ephydridae) and adaptation of Diptera to increased salinity

Larvae of many shore fly species (family Ephydridae) are adapted to living in water with high or extremely high salinity. Little is known about the morphological and physiological foundations of such adaptation. We described the details of the morphology of third-instar larvae of two shore flies: Ephydra riparia and Paracoenia fumosa and presented the scanning electron microscopy (SEM) images. For the first time, by silver-staining and SEM, we proved that the larvae of both studied species had anal organs (AO) – specialized structures that serve an osmoregulatory function and are responsible for the transport of ions from the environment to the larval hemolymph (but not in the opposite direction). We compared the larvae morphology of the studied species with some other shore fly species from the genera Ephydra, Paracoenia, Hydrellia, and Coenia, as well as with larvae of the model species Drosophila melanogaster (family Drosophilidae). Special attention was paid to the morphology of AO, which contribute to the adaptation of larvae to increased salinity. Extremely halophilic species either do not have AO, or they are poorly developed, while moderately halophilic shore flies have more developed features connected with the permeability of the AO cuticle and active ion transport. These features are most developed in freshwater shore flies. AO activity can vary due to the shape and area of the AO, the smoothness or wrinkling of the cuticle, and the presence of nanoscale pits on it. Described variability of AO structure is probably adaptive since, at high salinity, both the permeability of the AO cuticle and the active transport of ions from the environment to the hemolymph become less beneficial or even harmful.

Flow Cytometric Investigation of Salinicola halophilus S28 Physiological Response Provides Solid Evidence for Its Uncommon and High Ability to Face Salt-Stress Conditions

In a previous work, some bacterial strains isolated from the Saline di Tarquinia marine salterns (Viterbo, Italy) showed very unusual growth profiles in relation to temperature and salinity variations when grown in solid media. In particular, Salinicola halophilus S28 showed optimal or suboptimal growth in a very wide range of NaCl concentrations, suggesting a great coping ability with salinity variations. These intriguing outcomes did not fit with the general Salinicola halophilus description as a moderately halophilic species. Therefore, this study profiles the actual physiological status of S28 cells subjected to different NaCl concentrations to provide evidence for the actual coping ability of strain S28 with broad salinity variations. Flow cytometry was selected as the evaluation method to study the physiological status of bacterial cells subjected to different salinity levels, monitoring the strain response at different growth phases over 72 h. Strain S28 showed maximal growth at 8% NaCl; however, it grew very well with no statistically significant differences at all salinity conditions (4–24% NaCl). Flow cytometric results provided clear evidence of its actual and strong ability to face increasing salinity, revealing a good physiological response up to 24% of NaCl. In addition, strain S28 showed very similar cell physiological status at all salinity levels, as also indicated by the flat growth profile revealed in the range of 4–24% NaCl. This is the first study regarding the physiological response during the growth of halophilic bacteria under different conditions of salinity via flow cytometry. This technique represents an effective tool for the investigation of the physiological status of each cell, even if it is somehow underrated and underused by microbiologists for this purpose.

Delineating seagrass species in the genera Halodule and Halophila from Tanzanian coastal waters using ITS and rbcL DNA barcoding

The seagrass species in Halodule and Halophila may for several reasons be considered as taxonomic complexes. They show close evolutionary relationships, morphological plasticity and share similar features making misidentifications likely when morphological identification is applied. In Tanzanian coastal waters, there is some uncertainty about the identity of members of Halodule, particularly the existence of Halodule wrightii and the species composition of the Halophila ovalis complex. This study used morphology as well as internal transcribed spacer (ITS1 and ITS2) and ribulose‐bisphosphate carboxylase (rbcL) DNA barcoding to identify species of Halodule and Halophila. Seagrass samples were collected during low spring tides, from Tanzania's coastal waters of Tanga, Dar es Salaam, Mtwara, Mafia Island and Unguja Island, from August 2020 to February 2022. Morphological diagnosis, phylogenetic analysis and evolutionary divergences inferred from the ITS gene supported the identification of five species, namely Halophila ovalis, H. minor and H. stipulacea, with the first two forming the H. ovalis complex; as well as Halodule uninervis and H. pinifolia. It is the first time that H. pinifolia is reported in Tanzania. This is the first study reporting the delineation of seagrass species in East African coastal waters using DNA barcoding coupled with morphology.

Heavy metal (Cr, Cu, Ni, Pb, and Zn) contents of endemic Salvia halophila plants around Lake Tuz

Heavy metals occur naturally in ecosystems at varying concentrations. However, heavy metal sources that have emerged in present-day mainly due to human influence, i.e. industrial activities, agricultural waste, pesticides, use of fossil fuels and traffic, have included a part of heavy metals in the ecosystem. Lake Tuz, together with the entire lake surroundings, water beds and important steppe areas, was declared Turkey’s Specially Protected Area (SPA) in 2001. Our aim in this investigation was to determine the levels of heavy metals such as Chrome (Cr), Copper (Cu), Nickel (Ni), Lead (Pb) and Zinc (Zn) in endemic Salvia halophila grown in different areas of Lake Tuz. The results of the heavy metal contents analyzed at the plant were compared with the international standard levels of heavy metals. The consequences displayed that differing extents of heavy metals are accumulated in S. halophila. The results obtained differed in accordance with the collection time and localities. When the outcomes are appraised, it is achievable to say that Pb is higher than the standard values. The findings of this investigation are the first reported results for this endemic S. halophila species that grows naturally at Lake Tuz and are important as they are newly discovered results.

Species composition of cyanobacteria of Lake Tuzkol and study of morphological and cultural properties of isolated cultures

The species diversity of cyanobacteria of Lake Tuzkol, located on the left bank of the upper reaches of the Charyn River in the Rayymbek district in the south-east of the Almaty region, was studied. Microbial biodiversity represents the largest untapped reservoir for the potential discovery of new promising species of microorganisms. The aim of the study was to study the species diversity of Lake Tuzkol and identify promising cyanobacteria species. According to the results of the study of cyanobacteria (Cyanobacteria), 12 species were found in plankton, 15 species in periphyton. The ecological characteristics of cyanobacteria in relation to halobacteria indicate the salinity of the lake under study, there is a predominance of halophilic species. In addition, it was revealed that there are cyanobacteria species in the lake that are indifferent to the salinity of the environment. Indicators of saprobicity were 70% of cyanobacteria. The assessment of the state of the lake water by indicator species of phytoplankton showed that it belongs to the category of oligo-betamezosaprobnaya. The saprobic index according to the Pantle and Bukka method is 1.4. According to the results of work on the isolation of pure cultures from samples taken from the Tuzkol lake, 2 algologically pure cyanobacteria cultures were obtained:. The isolated cultures of cyanobacteria showed high productivity in the nutrient medium BG -11, at a temperature of 30-320C and a light intensity of 6000 lux. Keywords: species composition, biodiversity, cyanobacteria, Lake Tuzkol, saprobicity, algologically pure cultures.

Characterisation of the photosynthetic complexes from the marine gammaproteobacterium Congregibacter litoralis KT71

Possibly the most abundant group of anoxygenic phototrophs are marine photoheterotrophic Gammaproteobacteria belonging to the NOR5/OM60 clade. As little is known about their photosynthetic apparatus, the photosynthetic complexes from the marine phototrophic bacterium Congregibacter litoralis KT71 were purified and spectroscopically characterised. The intra-cytoplasmic membranes contain a smaller amount of photosynthetic complexes when compared with anaerobic purple bacteria. Moreover, the intra-cytoplasmic membranes contain only a minimum amount of peripheral LH2 complexes. The complexes are populated by bacteriochlorophyll a, spirilloxanthin and two novel ketocarotenoids, with biophysical and biochemical properties similar to previously characterised complexes from purple bacteria. The organization of the RC-LH1 complex has been further characterised using cryo-electron microscopy. The overall organisation is similar to the complex from the gammaproteobacterium Thermochromatium tepidum, with the type-II reaction centre surrounded by a slightly elliptical LH1 antenna ring composed of 16 αβ-subunits with no discernible gap or pore. The RC-LH1 and LH2 apoproteins are phylogenetically related to other halophilic species but LH2 also to some alphaproteobacterial species. It seems that the reduction of light-harvesting apparatus and acquisition of novel ketocarotenoids in Congregibacter litoralis KT71 represent specific adaptations for operating the anoxygenic photosynthesis under aerobic conditions at sea.

Isolation and Sequencing of Novel Vibrio Species.

Whole-genome sequencing of bacteria facilitates their genotypic analysis and expands our understanding of the tree of life on Earth. The Vibrio genus comprises many halophilic species of bacteria, including some that are pathogenic to humans and other animals. Here I describe methods for isolating and sequencing both known and novel species of Vibrio from saltwater environments. The first section outlines methods of isolating and phenotypically characterizing strains, followed by purification of their total DNA. The second and third sections outline methods of whole-genome sequencing and assembly, annotation, and phylogenetic analysis.

Transcontinental Dispersal of Nonendemic Fungal Pathogens through Wooden Handicraft Imports.

ABSTRACTThis study examined the viability and diversity of fungi harbored in imported wooden handicraft products sold in six retail stores in Florida, United States. Despite being subjected to trade regulations that require various sterilization/fumigation protocols, our study demonstrates high survival and diversity of fungi in wood products originating from at least seven countries on three continents. Among these fungi were nonendemic plant and human pathogens, as well as mycotoxin producers. Several products that are sold for use in food preparation and consumption harbored a novel (to North America) plant and human pathogen, Paecilomyces formosus. In addition, a high number of species isolated were thermophilic and included halophilic species, suggesting adaptability and selection through current wood treatment protocols that utilize heat and/or fumigation with methyl-bromide. This research suggests that current federal guidelines for imports of wooden goods are not sufficient to avoid the transit of potential live pathogens and demonstrates the need to increase safeguards at both points of origin and entry for biosecurity against introduction from invasive fungal species in wood products. Future import regulations should consider living fungi, their tolerance to extreme conditions, and their potential survival in solid substrates. Mitigation efforts may require additional steps such as more stringent fumigation and/or sterilization strategies and limiting use of wood that has not been processed to remove bark and decay.

Halophilic species of the genus Scrobipalpa Janse, 1951 (Lepidoptera: Gelechiidae) in Poland

Halophilic species of the genus Scrobipalpa Janse, 1951 (Lepidoptera: Gelechiidae) in Poland