Journal of Phycological Research
Volume:4 Issue: 2, Sep 2020

Symbiotic dinoflagellates produce bioactive valuable compounds such as carotenoids and lipids used in various industrial fields. However, a small amount of their biomass can be produced with a suspension-based closed photobioreactors. In the present study, we attempted to obtain a high lipid and total carotenoid contents from Symbiodinium sp. by creating optimal light intensity conditions using a Twin-layer photobioreactor. The growth rate, biomass, chlorophyll a concentration, as well as total carotenoid and lipid contents were examined at the light intensities of 50, 100 and 250 μmol m-2 s-1 for 16 days. Based on the results, biomass productivities ranged from 35.7, to 72.0 g m-2 at 50 and 250 µmol photons m-2 s-1, respectively. The highest linear growth rates were obtained 2.03, 3.27, and 5.85 g m−2 d−1 between 12 and 16 days at light intensity of 50, 100, and 250 μmol m−2 s−1, respectively. The highest values of total carotenoids, chlorophyll a, and percentage of total lipid were 0.85 g m-2, 0.96 g m-2, and 27.77% at light intensity of 250 μmol m-2 s-1, respectively. The findings proved that immobilization of algal cells in the photobioreactor biofilm resulted in high production of biomass and total carotenoids and lipids.

Mighan Lake is located 8 kilometers northeast of Arak city. Lake surface area is 112 km2. Dunaliella salina (Dunal) Teodoresco composing main phytoplankton population and food chain in the lake. Salinity depending on season and water input is between 20-120 g/l. This study evaluated the impact of salinity and physicochemical factors on the lake’s phytoplankton communities. Sampling was done monthly during March to December 2019. Species and phytoplankton density were determined by inverted microscopy. Twelve algal species were identified which D. salina consisted 87.3% of phytoplankton composition. Indeed, salinity as a major limiting factor reduced phytoplankton diversity in Mighan Lake.

The contamination of heavy metals is a major environmental obstacle, threatening human health through the food chain. Here, we studied the pollution status of six heavy metals (Cu, Zn, Pb, Ni, Fe and Cd) through investigating 12 seaweed species collected from different intertidal areas of the Persian Gulf and Gulf of Oman. The seaweed species were also studied for the difference in the heavy metals uptake. Our results confirmed the heavy metals contamination in all seaweed species tested. The results also revealed that the heavy metal uptake was affected by type of heavy metal (P ≤ 0.0001). In addition, we showed that type of seaweed species and collection site affected the heavy metal uptake. Accordingly, the highest content of Fe (2844 ppm) was found in Dictyota sp. and the highest content of Nickel (Ni) was observed in Padina gymnospora (105.97 ppm) and Hypnea sp. (100.41 ppm). Also, the highest concentration of Zinc (Zn) (58.46 ppm) and Cupper (Cu) (32.44 ppm) was found in Sargassum angustifolium and S. boveanum, respectively. Among the studied heavy metals, Cadmium (Cd) had the lowest concentration in all seaweed species, ranging from 4.8 ppm in S. angustifolium to 10.7 ppm in Dictyota sp. Gracilariopsis persica was the only species showed the lowest content of all heavy metals tested. Our findings revealed that brown macroalgae (Phaeophyta) had higher level of contamination compared with green (Chlorophyta) and red (Rdodophyta) macroalgae.

The results revealed that salinity application (80 and 160 mM) after 20 minutes of inoculation significantly increased the yield of phycobilisome system. Increasing the time up to 40 minutes after inoculation will restore all parts of the photosynthetic system. After this time, cyanobacteria are able to rearrange and activate photosystem II, phycobilisome, and light-collecting complex. Athough, the behavior of cyanobacteria at salinity of 160 and 80 mM are opposite at times of 20 and 60 min. Compared to the untreated sample, pretreatment application within less than one hour changesin growth rate and attenuation at time intervals of 24 and 96 hours. The sample is capable of moderating the destructive effects of 160 mM for 20 minand 80 mMin 60 min treatments over 24 hours, which is not complete. The growth rate of up to 96 h in 80 mM for 20 min and 160 mM for 60 min treatments was higher than those without salinity. While,the system changes its pattern after 24 hours, the initial pattern remains unaffected by the time and salinity levels after this time

Cyanobacteria or Blue-Green algae are photosynthetic prokaryotic organisms found in most ecological habitats. Different species of cyanobacteria are found in the hot springs. Hot springs are great examples of extreme habitats for organisms with ‘sub cosmopolitan’ geographical distribution, species happen throughout the world but only in ‘appropriate’ habitats. In thousand year ago, these ecological areas have been noticing tourism and therapeutic and organisms in them have attracted biologists. In this study, the identification of cyanobacteria was studied in five springs of Sarisou, Goshayesh, Ghareh Palchiq, Shour Sou and Isty Bulakh located in East Azarbaijan province, Maragheh city. The physicochemical analysis of springs water was carried out due to their effect on algal communities. In order to minimize the quantitative and qualitative changes of phytoplankton after sampling, the samples were fixed in formaldehyde % 4 solution. As a result of this study, a total of 30 species were identified. The highest diversity of cyanobacteria was observed in the Isty Bulakh spring with 15 species and seven genera due to lower turbidity and total hardness compared to other springs. In contrast, Ghare Palchigh spring show the least diversity of cyanobacteria due to high total hardness and turbidity. Among the taxa identified from all stations, the genus Phormidium showed the highest diversity.

Waterfalls are aquatic ecosystems that a few studies on biodiversity of this freshwater systems were reported. Golestan waterfall is one of the outstanding waterfalls in eastern end of Golestan National Park. This study was conducted to to identify epilithic diatoms of this waterfall as a component of biodiversity of this ecosystem, due to the fact that no study has been done on algal flora in this. Sampling was done at seasonal interval from stony substrates. The results were revealed 24 including 47 species which all taxa belonged to the class Bacillariophyceae. Cymbopleura with 5 species was the most species rich genus following by Gomphonema and Navicula with 4 species. Achnanthidium minutissimum, Amphipleura pellucida, Cymbella affinis, Cymbopleura kuelbsii and Gomphonema pumilum were the most abundant taxa. Delicatophycus verenae M.J.Wynne, Stauroneis separanda Lange-Bertalot & Werum and Tryblionella brunoi (Lange-Bertalot) Cantonati & Lange-Bertalot are recorded for the first time for diatom flora of Iran. Due to the few diatom studies there are no valid flora on diatoms in Iran, thus detailed and local studies can improve the knowledge on diatoms.