Journal of Phycological Research
Volume:7 Issue: 1, Jun 2023

Diatoms are a key group of organisms of the periphyton and have a significant contribution to primary production in rivers. Despite their importance, little information exists about the taxonomy and distribution of periphytic diatoms in Iran. Central Alborz is one of the hotspots known globally for its fauna and flora and the Damavand River is one of the permanent rivers flowing in the region. Epilithic diatom samples were taken along the Damavand River basin between the summer of 2017 and the spring of 2019 to determine the benthic diatom flora. As a result, five species within the genera Gomphonema, Cymbella, Cymbopleura, and Sellaphora were found as new records from the Central Alborz. These species include Cymbella affinis var. angusta (Krammer) W. Silva, Cymbopleura similiformis Krammer, Gomphonema innocens Reichardt, Sellaphora capitata D.G. Mann & S.M. McDonald and Sellaphora lanceolata D.G. Mann & S.J.M. Droop.  The morphology of these taxa, comparisons to similar taxa, and geographic distributions are discussed. These results expand the knowledge of diatom diversity in the Central Alborz Region.

The genus Tripos (the marine Ceratium) often comprises a major part of micro-phytoplankton in terms of abundance and diversity that plays an important role in annual primary production; however, it has received little attention in the Persian Gulf. The morphology and phylogeny of Tripos furca, T. massiliense, and T. concilians were investigated in the present research. Samples collected from the Persian Gulf were identified morphologically under an inverted microscope, and the SSU rDNA sequence from individual cells was amplified using a polymerase chain reaction. The SSU rDNA sequence was determined for Iranian strains of these species and registered in the GenBank. The results of the phylogenetic analysis indicated the formation of a monophyletic clade of the family Ceratiaceae with high support. In this clade, freshwater species of Ceratium were grouped in a highly supported subclade, and marine species comprised another subclade. These results well demonstrated the separation (divergence) of marine and freshwater species of Ceratium. Altogether, the present results agree with previous studies where a considerable evolutionary distance is suggested for marine and freshwater species and support the formation of two highly distinct monophyletic clades based on SSU rDNA and LSU rDNA fragments and the number of cingular plates.

Natural ponds are renowned for harboring a unique microalgal community, encompassing a wide diversity of common and rare species, including diatoms, cyanobacteria, and green microalgae. Yet, no comprehensive floristic study has ever been conducted on the natural ponds within the Shibkouh District. In this study, water and soil samples were collected from three distinct sites within the Shibkouh District (water bodies, wetland, and soil) to investigate the algal diversity present in these habitats. To cultivate the collected samples for further analysis, two different culture media were employed - BG11 and BG11: 1.5 M NaCl. Notably, an intriguing occurrence observed during this study was the bloom of Dunaliella salina in its green phase specifically in the semipermanent pond. Our findings revealed a total of 26 taxa comprising 12 genera of cyanobacteria, four genera of diatoms, and two genera of Chlorophyta. Remarkable variations were observed in both species richness and taxonomic composition between aquatic and terrestrial ecosystems. Furthermore, notable differences were observed when comparing samples cultured in different types of culture media. Diatoms were also identified as the dominant microorganisms adapted to extreme conditions typically found within wetland habitats (Site 2). This Site exhibited higher taxa richness compared to other sampling locations. As a result, these natural ponds have a vital role in preserving algal biodiversity. They serve as habitats not only for typical freshwater microalgae but also for halotolerant taxa such as diatoms that can thrive under difficult environmental conditions.

Cysts produced by dinoflagellates act as the seeds involved in the initiation of algal bloom through blooming and at the end of bloom through the reformation of cysts. Therefore, they are of great importance in environmental studies. In this study, sampling of sediments in the Gwater Bay, located on Iran's southeast coast and the northeast of the Oman Sea, was done in the spring (pre-monsoon) and summer (post-monsoon) of 2013 to examine the distribution and abundance of dinoflagellate cysts. Twenty-four species belonging to 12 genera of the dinoflagellate cysts were identified for the first time in this area. The results of ANOVA indicated no significant difference between the abundance of cysts in different seasons. A study of the Shannon index in this area revealed a high diversity and abundance in the study area. In this study, 8 species of dinoflagellate were found as potentially toxic species.

The effects of plant inoculation with plant growth-promoting cyanobacteria on the activity of phenylalanine ammonia-lyase (PAL), peroxidase (POD), and cell wall POD enzymes in Thymus vulgaris L. were investigated. A greenhouse experiment with five replications was carried out using inoculation of five cyanobacteria suspensions (2.5%) including Anabaena torulosa ISB213, Nostoc calcicola ISB215, Nostoc ellipsosporum ISB217, Trichormus doliolum ISB214 and Oscillatoria sp. ISB2116 on T. vulgaris plants. After four months, the plants were harvested, and the enzyme levels were measured. The statistical analysis revealed that the treatment with N. ellipsosporum ISB217 had the most significant impact on PAL enzyme activity in the treated plants. Compared to the control group (0.13 ± 0.002), the plants treated with T. doliolum ISB214 exhibited the highest activity of POD (0.69 ± 0.03) enzyme and cell wall POD (0.53 ± 0.05). Also, the amount of lignin in the treated plants had a significant increase compared to the control. Considering the valuable medicinal properties of the secondary metabolites found in thyme plants and the crucial role of nutritional management in enhancing the production and quality of this medicinal plant. The usage of appropriate growth stimulants has the potential to enhance the biosynthesis of these compounds. This study demonstrated that application of microalgae extract as a completely natural and eco-friendly substance by increasing the enzymes activity related to the synthesis of cell wall materials can boost the resistance of plants against biotic and abiotic stresses.

The debate on biodiversity is one of the most important issues in today’s world. In this study, we focused on the examination and characterization of cultivable algae in the unconventional waters of Semnan and Garmsar. Sampling was conducted at eight different locations and employed microscopic and molecular techniques to identify the algae’s morphological and genetic features. Through microscopic analysis, we were able to identify the visible and structural traits of the algae accurately. The molecular identification involved analyzing the 18S rRNA and 16S rRNA genes and conducting BLAST searches on the NCBI database. Additionally, we constructed a phylogenetic tree using MEGA software (version 6). Out of the 10 strains identified, six belonged to the chlorophytes, while four were classified as The debate on biodiversity is one of the most important issues in today’s world. In this study, we focused on the examination and characterization of cultivable algae in the unconventional waters of Semnan and Garmsar. Sampling was conducted at eight different locations and employed microscopic and molecular techniques to identify the algae’s morphological and genetic features. Through microscopic analysis, we were able to identify the visible and structural traits of the algae accurately. The molecular identification involved analyzing the 18S rRNA and 16S rRNA genes and conducting BLAST searches on the NCBI database. Additionally, we constructed a phylogenetic tree using MEGA software (version 6). Out of the 10 strains identified, six belonged to the chlorophytes, while four were classified as cyanophytes. The antioxidant activity of the isolated strains was also evaluated using the ferric-reducing antioxidant power (FRAP) method. Furthermore, the total antioxidant activity of some strains was measured after inducing changes in cell color. The morphological and molecular methods helped us identify various genera, including Leptolyngbya sp., Scenedesmus sp., Coelastrella sp., Dunaliella sp., and Pseudanabaena sp. The results indicated a higher prevalence of Chlorophyta compared to other groups. Since there is a lack of previous research on algae identification in the Semnan Province, this study provides valuable insights into the local genetic resources of algae, which can serve as a foundation for future investigations.

This study tries to review the methods and stages of biodiesel production from the extracted oil of algae through a transesterification reaction. Biodiesel is a clean, renewable, biodegradable, and eco-friendly fuel. Algae are considered the third-generation and the most promising biodiesel feedstock because of their advantages including that microalgae have the potential to produce 25–220 times higher triglycerides than terrestrial plants and the growth rate of algae is approximately 20- 30 times faster than food-yielding crops. Algae can grow almost in all kinds of water such as fresh or waste waters and on non-arable and marginal land and engine performance and exhaust emission of microalgae biodiesel investigated. Due to the higher oil content in microalgae than macroalgae, it is a better feedstock for biodiesel production. This work studied the steps of biodiesel production from microalgae including cultivation of microalgae, harvesting, oil extraction, and especially how to create biodiesel from microalgae biomass through transesterification reaction by focusing on the kinds of catalysts that have been used for microalgal biodiesel production studied. Transesterification reactions are commonly catalyzed by acids or bases as chemical catalysts or carried out in the presence of enzyme catalysts as biocatalysts. Also, the advantages of using heterogeneous catalysts compared to homogeneous ones were investigated. Many efforts have been made to commercialize algae biodiesel but the high cost of producing algae and extracting its oil is challenging and it will still take some time before algal biofuels become a commercial reality in Iran and all the world.