Determination of ecological statuses of streams in the Ceyhan River Basin using composition and ecological characteristics of diatoms.

The present study aimed to evaluate the interactions between diatoms and ecological factors in various streams and to test the suitability of diatom indices to evaluate the ecological status of 44 streams in the Ceyhan River Basin during the spring and autumn periods of 2021 and the summer of 2022. Canonical correspondence analysis indicated the significant effects of electrical conductivity (EC), dissolved oxygen, biological oxygen demand (BOD5), total phosphorus (TP), and total nitrogen (TN) on the distribution of diatom species of streams in the Ceyhan River Basin. Of the streams, Aksu and Erkenez streams were associated with high EC, BOD5, and TP and characterized by pollution-tolerant species. Pollution-sensitive species showed close integration with Aksu Spring Brook, Gözpinar Creek, Göksun Creek, and Yesilgöz Spring Brook, which related to a high dissolved oxygen gradient. Different eco-regional diatom indices displayed different scores, representing from bad to high ecological status in the Ceyhan River basin. Among the diatom indices, Trophic Index Turkey (TIT) proved to be the more suitable metric to assess the ecological status of streams. TIT indicated deterioration of water quality in Karasu (S06), Erkenez (S07) streams, and downstream areas of the Ceyhan River and the least distributed sampling stations in the basin. Results suggested that eco-regionally developed diatom indices, like TIT, are required to more accurately assess the ecological status of streams in the Mediterranean region. The study provides a fundamental assessment of the ecological status of streams in the Ceyhan River Basin using an appropriate diatom index before the Pazarcik-centered earthquake on February 6, 2023. Findings allow someone to assess the impact of the earthquake on diatom communities and ecological factors in the region in the future studies.

Breathing life into Mars: Terraforming and the pivotal role of algae in atmospheric genesis.

The Martian environment, characterized by extreme aridity, frigid temperatures, and a lack of atmospheric oxygen, presents a formidable challenge for potential terraforming endeavors. This review article synthesizes current research on utilizing algae as biocatalysts in the proposed terraforming of Mars, assessing their capacity to facilitate Martian atmospheric conditions through photosynthetic bioengineering. We analyze the physiological and genetic traits of extremophile algae that equip them for survival in extreme habitats on Earth, which serve as analogs for Martian surface conditions. The potential for these organisms to mediate atmospheric change on Mars is evaluated, specifically their role in biogenic oxygen production and carbon dioxide sequestration. We discuss strategies for enhancing algal strains' resilience and metabolic efficiency, including genetic modification and the development of bioreactors for controlled growth in extraterrestrial environments. The integration of algal systems with existing mechanical and chemical terraforming proposals is also examined, proposing a synergistic approach for establishing a nascent Martian biosphere. Ethical and ecological considerations concerning introducing terrestrial life to extra-planetary bodies are critically appraised. This appraisal includes an examination of potential ecological feedback loops and inherent risks associated with biological terraforming. Biological terraforming is the theoretical process of deliberately altering a planet's atmosphere, temperature, and ecosystem to render it suitable for Earth-like life. The feasibility of a phased introduction of life, starting with microbial taxa and progressing to multicellular organisms, fosters a supportive atmosphere on Mars. By extending the frontier of biotechnological innovation into space, this work contributes to the foundational understanding necessary for one of humanity's most audacious goals-the terraforming of another planet.

Challenges in Functional Food Products with the Incorporation of Some Microalgae.

Much attention has been given to the use of microalgae to produce functional foods that have valuable bioactive chemicals, including essential amino acids, polyunsaturated fatty acids, vitamins, carotenoids, fiber, and minerals. Microalgal biomasses are increasingly being used to improve the nutritional values of foods because of their unique nutrient compositions that are beneficial to human health. Their protein content and amino acid composition are the most important components. The microalgal biomass used in the therapeutic supplement industry is dominated by bio-compounds like astaxanthin, ß-carotene, polyunsaturated fatty acids like eicosapentaenoic acid and docosahexaenoic acid, and polysaccharides such as ß-glucan. The popularity of microalgal supplements is growing because of the health benefits of their bioactive substances. Moreover, some microalgae, such as Dunaliella, Arthrospira (Spirulina), Chlorella, and Haematococcus, are commonly used microalgal species in functional food production. The incorporation of microalgal biomass leads not only to enhanced nutritional value but also to improved sensory quality of food products without altering their cooking or textural characteristics. Microalgae, because of their eco-friendly potential, have emerged as one of the most promising and novel sources of new functional foods. This study reviews some recent and relevant works, as well as the current challenges for future research, using different methods of chemical modification in foods with the addition of a few commercial algae to allow their use in nutritional and sensory areas. It can be concluded that the production of functional foods through the use of microalgae in foods has become an important issue.

Fuzzy logic as a novel approach to predict biological condition gradient of various streams in Ceyhan River Basin (Turkey).

Creating a method to categorize the ecological status of streams according to their biological conditions and establishing scientifically defensible nutrient criteria to protect their biotic integrity poses significant challenges. Biomonitoring of least disturbed areas is an important issue to accurately assess the ecological status of surface waters and ensure their sustainability. The fuzzy logic as a novel approach was firstly applied to evaluate the biological condition gradient of 44 sampled streams in the Ceyhan River Basin, utilizing two diatom indices, total phosphorus (TP), electrical conductivity (EC), and CORINE data. The fuzzy logic was employed to examine variations in the diatom compositions and land cover based on biological condition gradients (BCGs) of various streams and to assess the suitability of BCG in evaluating the health of studied stream systems. A three-layer fuzzy logic was constructed to predict BCGs of steams based on input data, with diatom metrics, TP, and EC representing BCGdia and land cover variables contributing to BCGland. The effects of operating variables were studied to optimize BCG results. The highest BCG score (0.85) was determined in Aksu Spring Brook in the spring, whereas the lowest value (0.05) was calculated in Erkenez Stream3 in the summer. BCGs showed strong relationships with nutrients, altitude, and EC. Results of BCGs indicated that sampling stations have various ecological statuses ranging from bad to high in the Ceyhan River Basin. The BCGdia and BCGland made important contributions to determine the ecological status of streams in the Ceyhan River Basin. Results showed that the BCG approach allows a more reliable way to determine the ecological status of streams in the Ceyhan River Basin by combining biological and chemical assessments for the sustainability of the environment. It is recommended that the BCG will be applied and evaluated in future research studies across various river basins, both within and outside of Turkey.

Effect of lead ions on biochemical behavior of Cladophora glomerata in sterilized and non-sterilized media.

Freshwater ecosystems are under peril globally due to anthropogenic influences, most notably metals. The present study aimed to evaluate the morphological and biochemical responses of Cladophora glomerata obtained from a freshwater stream to various lead concentrations (0.0, 7.5, 15, 30, and 60 mg/L Pb2+) in sterilized and non-sterilized media. Pigments, proline, malondialdehyde (MDA), total phenolic compounds (TPC), hydrogen peroxide, and protein content of the green alga were determined in response to various growing conditions. Pb2+ stress had a detrimental effect not only on biochemical components of C. glomerata but also on the algal cell's shape and surface structure. High Pb2+ concentrations significantly decreased chlorophyll-a (from 1350 µg/g in non-sterilized and 1340 µg/g in sterilized media for the control group to 1067 µg/g in non-sterilized and 1049 µg/g in sterile media at 60 mg/L Pb2+) and protein contents (from 34.47 mg/g for the sterilized and 35.89 mg/g for non-sterilized of the control to 24.82 mg/g for the sterilized and 26.18 mg/g for the non-sterilized at 60 mg/L Pb2+) of algal biomass but increased the concentrations of stress compounds (e.g., MDA, proline, and TPC). Variation in the macroalgal biomass composition was also indicated by FTIR analysis based on interactions between amino, amide, and anionic surface groups on the algal biomass and Pb2+ ions. Morphological and biochemical responses of C. glomerata reveal that non-sterile conditions encouraged the proliferation of this macroalga under Pb2+ exposure.

Assessing relationships between environmental stress and benthic diatoms in lentic habitats in the western Mediterranean basin (Turkey).

Hydrological (rainy and dry) periods can affect the water quality of lentic ecosystems, which may be useful for understanding their ecological condition in the watershed. Ecological status of various lentic ecosytems (both brackish and freshwater) in the western Mediterranean basin was evaluated by using various diatom metrics throughout rainy (May) and dry (August and October) periods to explain the diatom-stressor interactions using multivariate approaches. Canonical correspondence analysis separated freshwater habitats under the pressures of nitrate and total organic carbon from brackish ecosystems under the pressures of conductivity, nitrite, sulphate, calcium, and copper, which were characterized by different phytoplankton species. Ecological integrations of diatom species varied in the ecosystems throughout rainy and dry periods. Different ecological regional diatom indices were used to find the best index/indices indicating the ecological status of lakes and reservoirs in the basin during the two hydrological periods. The trophic diatom index developed for lakes was not found to be suitable for assessing lentic habitats. European diatom indices generally showed the distinction in the assessment of these ecosystems in the rainy and dry seasons, but others could not. Among the diatom indices, only the trophic index Turkey (TIT) showed a statistically significant correlation with TP. The TIT not only showed degradation of the water quality of ecosystems during the dry season compared to the rainy season, but it has also been successful in distinguishing the ecological conditions of lentic ecosystems.

Eco-assessment of streams of Konya closed river basin (Turkey) using various ecoregional diatom indices.

Ecological assessment of freshwater ecosystems based on diatom metrics is an important issue for attaining environmental sustainability. The present study aimed to evaluate differences in the diatom-stressor relationship in relatively least disturbed streams in the Konya closed river basin using multivariate analyses and to bio-assess streams by the application of different ecoregional diatom indices. Cocconeis euglypta, Cymbella excisa, Cocconeis placentula, and Achnanthidium minutissimum are the most contributing species to the dissimilarity of sampling stations between rainy (spring) and dry (summer and fall) seasons and also between altitude (A2 800- < 1600 m and A3 ≥ 1600 m) groups. The first two axes of canonical correspondence analysis revealed a significant (82.8%) relationship between diatom species and stressors. Diatom species displayed distinct responses to environmental variables (electrical conductivity, Ni, Cu, B, and altitude) playing important roles on the distribution of species. Diatom indices indicate different ecological statuses of stations, from bad to high. European diatom indices except Duero Diatom Index (DDI) and Trophic Diatom Index (TDI) showed good responses to the eco-assessment of streams and indicated high ecological status for the least disturbed sampling stations symbolized as S16, S20, S24, S25, S27-29, S37, and S39. These results were also supported by abiotic evaluation. Although TIT was more competitive in the bio-assessment of streams among diatom indices, it is necessary to increase its species list by determining their trophic weights in future studies. Therefore, the use of ecoregion-specific diatom indices is suggested along with increasing the number of used species to correctly interpret the water quality.

Eco-assessment of least disturbed areas of the Antalya River basin: application of diatom indices from different ecoregions.

Biomonitoring of least disturbed areas is a crucial issue to accurately assess the ecological status of surface waters and ensure their sustainability. Diatom metrics are important tools for the assessment of environmental conditions of lotic ecosystems to achieve environmental sustainability. The present study was aimed to evaluate the ecological status of least disturbed areas in the Antalya River basin (Turkey) using diatom indices developed from different ecoregion. Diatom species such as Cymbella excisa, Achnanthidium minutissimum, Cocconeis euglypta, and Cocconeis placentula were the most contributing species to the dissimilarity of sampling stations between rainy and dry seasons. The first two axes of canonical correspondence analysis (CCA) elucidated a strong (86%) correlation between diatom taxa and stressors. Results of the Monte Carlo permutation test indicated that total phosphorus (TP), water temperature, Tin (Sn), total organic carbon, zinc, and pH are significantly influential ecological factors on the distribution of diatom taxa among sampling stations. The Spearman correlation rank test indicated that diatom indices had significant positive and negative correlations with TP gradient. Results revealed that diatom indices developed from different ecoregions have different scores for the eco-assessment of similar sampling stations. European diatom indices mostly showed similar behavior in the bioassessment of the ecological status of rivers in the Antalya region compared to the different ecoregion. Among European diatom indices, TIT was more competitive and could give better results in the bio-evaluation of rivers in the Antalya River basin. Using diatom indices developed from different ecoregions may lead to an erroneous assessment of water quality. Accordingly, ecoregional specific diatom metrics are needed to accurately determine the surface water quality. Eco-assessment of least disturbed areas of the Antalya River basin: application of diatom indices from different ecoregions: Abuzer Çelekli, Ömer Lekesiz, Tolga Çetin.

Trace elements in patients with aortic valve sclerosis.

BACKGROUND: Aortic valve sclerosis (AVSc) is defined as the thickening and calcification of aortic valve cusps, in the absence of obstruction of ventricular outflow. AVSc is linked with a clear imbalance in some trace elements. AIMS: The objective of this study was to investigate the relationship between AVSc and serum levels of iron (Fe), zinc (Zn), selenium (Se), and copper (Cu). Additionally, this research aimed to explore the clinical significance of human serum zinc, selenium, copper, and iron concentrations as a potential new biomarker for AVSc patients and to clarify the pathophysiological role in individuals at risk of developing AVSc. PATIENTS AND METHODS: The study included 40 subjects with AVSc (25% male and 75% female) who were compared with a healthy control group with the same gender ratio. AVSc was based on comprehensive echocardiographic assessments. Blood samples were taken and Zn and Cu concentrations were determined through the use of atomic absorption spectroscopy. Se was measured using an inductively coupled plasma mass spectrometry device and Fe was measured using a Beckman Coulter instrument. RESULTS: There was a significant difference in the prevalence of diabetes, blood pressure levels, and body mass index between the patients and the healthy subjects (p < 0.05). The differences between the serum Fe, Se, and Cu levels of the AVSc patients and the healthy subjects (p > 0.05) were recorded. The serum Zn of AVSc patients when compared was significantly lower compared with that of the control group (p < 0.01). CONCLUSION: Patients with AVSc had an imbalance in some of the trace elements in their blood. The patient group's valves had higher serum Cu levels and lower serum Se, Zn, and Fe concentrations compared with the healthy group's valves. In the valve patients as compared, AVSc had a high prevalence of obesity, hypertension, and diabetes.

Limno-ecological assessment of lentic ecosystems in the western Mediterranean basin (Turkey) using phytoplankton indices.

Great attention has been given to freshwater ecosystems worldwide due to the increased exploitation of water resources and the degradation of water quality. This study was aimed to demonstrate the phytoplankton-stressor interactions using multivariate approaches and assess the ecological conditions of 28 sampling stations of 12 lentic ecosystems (five lakes and seven reservoirs) in the western Mediterranean basin using phytoplankton indices in dry and rainy seasons 2018. Freshwater and brackish water systems were separately ordinated by canonical correspondence analysis. The brackish ecosystems were under pressures of Ar (arsenic), N-N[Formula: see text] (nitrite), Ca (calcium), EC (electrical conductivity), Cl (chloride), B (boron), etc., whereas shallow freshwater ecosystems were associated with total organic carbon. These factors had significant effects on phytoplankton distribution among lentic ecosystems on the basin. Ecological associations of phytoplankton assemblages varied in the western Mediterranean basin during the study. Pseudanabaena catenata and Palatinus apiculatus, considered tolerant taxa, are associated with higher Ar, EC, and V (vanadium) while Desmodesmus abundans and Microcystis flos-aquae are related to total organic carbon. The modified PTI (phytoplankton trophic index) had the highest correlation coefficient value. Scores of the PTI varied from 2.02 in Çavdir Reservoir to 2.59 in Lake Kocagöl. Results of phytoplankton indices indicated that two (Gölhisar and Yazir) lakes and two (Yaprakli and Çavdir) reservoirs were classified as Good, and three lakes and five reservoirs were classified as Moderate condition. Other predicted classifications (high, poor, and bad) by phytoplankton metrics were not represented. The modified PTI could be a suitable phytoplankton metric for assessing the ecological status of lentic ecosystems in the Mediterranean system according to its highest correlation coefficient value. Overall, the results of this limno-ecological study demonstrated that responses of phytoplankton taxa to explanatory factors provide crucial ecological information about their ecology and to estimate the ecological status of lentic ecosystems.

Eco-assessment of West Mediterranean basin's rivers (Turkey) using diatom metrics and multivariate approaches.

Bio-evaluating of surface waters is not a new approach but is becoming more important since the application of the European Water Framework Directive (WFD). The present study was designed to evaluate the limno-ecological conditions of rivers in the West Mediterranean basin of Turkey using diatom metrics and multivariate approaches according to the WFD requirements. Canonical correspondence analysis (CCA) was used to assess the relationships of diatom species and environmental variables from 17 stations of 12 rivers sampled in two seasons. The CCA indicated that nitrite, chloride, electrical conductivity (EC), sulfate, temperature, and total phosphorus (TP) are the most explanatory factors on the distribution of the diatom species. Karasu River had the most deteriorated ecosystem, distinctly revealed by the CCA. Nutrient enrichment and high EC, biological oxygen demand (BOD5), and temperature values were noticed in this ecosystem. Karasu River was also characterized by pollution tolerant diatom species (e.g., Nitzschia inconspicua, Nitzschia pusilla, Halamphora normanii, and Rhoicosphenia abbreviata). Trophic index Turkey (TIT), eutrophication and/or pollution index-diatom (EPI-D), and trophic index (TI) showed poor ecological conditions in Karasu and Hamzabey rivers when a moderate environment quality in Dalaman River (at R6 station) and a good ecological state in Kocadere River. A high ecological status was found in Dalaman (at R5 station) concerning the results of TIT and TI, while a good condition was recorded based on EPI-D. This ecosystem was also associated with pollution-sensitive diatom taxa (Achnanthidium minutissimum, Cymbella excisa, Meridion circulare, and Gomphonema olivaceum). Results of CCA were corroborated with the bio-assessment of sampling stations based on diatom metrics. TIT, TI, and EPI-D had different indices' scores, but they showed significantly positive correlations with logTP. Spearman correlation coefficient value of TIT strengthens the suitability of it for the bio-assessment of the rivers in the West Mediterranean basin of Turkey.

Limno-ecological assessment of Aras River surface waters in Turkey: application of diatom indices.

This study is the first attempt to evaluate the limno-ecological status of freshwater ecosystems in Aras River system (Turkey) using diatom metrics and multivariate analyses according to the European Union Water Framework Directive requirements. Samples were collected using the standard protocols from 17 sampling stations in August and October of 2014, and June of 2015. Deterioration of water quality in the Aras River catchment was remarked from the downstream of Karakoyunlu, Sarisu, and Bozkus creeks, which showed higher values of trophic index Turkey (TIT), trophic index (TI), and eutrophication and/or pollution index-diatom (EPI-D). These sites were also characterized by pollution tolerant taxa e.g., Cocconeis placentula, Gomphonema parvulum, Navicula cryptocephala, Navicula trivialis, and Tryblionella angustata. Sites S14-S17 had high ecological status according to TIT, supported by the score of EPI-D which indicated a good ecological condition for S14. The occurrence of pollution-sensitive species (e.g., Hannaea arcus, Cymbella affinis, Didymosphenia geminata, Meridion circulare, and Encyonema silesiacum) and the low nutrients like total phosphorus, orthophosphate and nitrate, conductivity, and BOD5 supported the high ecological status of S14-S17. The relationships between diatom assemblages and environmental variables were also illustrated by multivariate analyses. Spearman correlation analysis revealed that TIT had positive important correlations with total phosphorus (p < 0.01, r = 0.768). Trophic index and EPI-D had also significant correlations with environmental variables, but they had lower correlation coefficient than that of TIT. It seems that TIT could be a suitable diatom metric for assessing the ecological status of sampling stations in Aras River system and Mediterranean region. Our findings showed also that ecological statuses of surface waters should be evaluated due to the indices developed in their ecoregions.

Development of a new adsorbent from pumpkin husk by KOH-modification to remove copper ions.

Heavy metal pollution in watercourses is a major environmental problem throughout the world due to rapid population growth, industrialization, and economic development. Considering this, the present study aimed to develop a new adsorbent from pumpkin husk (PH) by KOH modification to remove copper (Cu2+) ions and to explore its adsorptive potential. The sorption studies of Cu2+ on KOH-modified PH were carried out as functions of particle size, solution pH, adsorbent dose, temperature, initial metal concentration, and contact time. The sorption capacity of KOH-modified PH was found to be higher than that of raw PH, as 19.4 and 10.2 mg g-1, respectively. Morphology and surface structures of adsorbents were characterized by determination of zero point charge, a Fourier transform infrared spectrometer (FTIR-ATR) spectra, and a scanning electron microscopy (SEM) of PH powders before and after the sorption of Cu2+. The pHzpc of PH was found to be 5.0. FTIR-ATR analyses indicated that amino, amide, hydroxyl, carboxyl, and oxygenated groups of PH play an important role in the sorption process. Sorption isotherm, kinetic, and thermodynamic parameters of Cu2+ on KOH-modified PH were studied. The kinetic process was well represented by the Logistic model. The maximum sorption was found as 73.16 mg g-1 according to the well-fitting of Langmuir isotherm. Results of sorption and thermodynamic studies indicated that the process was exothermic, being feasible, and spontaneous. KOH-modified PH as an eco-friendly adsorbent had great potential to remove Cu2+ ions from aquatic system.

The role of human urotensin-II in patients with hypertrophic cardiomyopathy.

OBJECTIVE: Hypertrophic cardiomyopathy (HCM) is a genetic condition with the hallmark feature of left ventricular hypertrophy. Human Urotensin-II (hUT-II) is regarded as a cardiovascular autacoid/hormone, and it has cardiac inotropic and hypertrophic properties. Aims of this study were to elucidate the clinical significance of serum hUT-II levels as a potential new biomarker in patients with HCM. METHODS: This study included 40 HCM patients (60% males and 40% females) and were compared to 30 healthy control subjects (47% males and 53% females. All patients underwent extensive clinical, laboratory, and echocardiographic. Blood samples were taken to test for serum hUT-II levels by commercial ELISA Kit. RESULTS: Serum hUT-II was significantly higher (p < 0.01) in patients with HCM (15.8 ± 2.1 pmol/L) compared with healthy controls (3.3 ± 1.7 pmol/L). With regard to HCM patient, Serum hUT-II levels were significantly higher in the female with 16.3 ± 1.9 pmol/L than the male with 15.4 ± 2.2 pmol/L (p < 0.05). Among echocardiographic parameters, hUT-II was negatively associated with ejection fraction (r = -0.160, p = 0.324). CONCLUSION: Results of the first study indicated that serum hUT-II levels were markedly elevated in patients with HCM. Serum hUT-II is a novel biomarker parameter that has clinical use in patients with the severity of LVH.

Evaluating biochemical response of filamentous algae integrated with different water bodies.

The present study prompted the second attempts to evaluate biochemical responses of filamentous algae under different physico-chemical variables in various water bodies in Turkey. These variables were investigated by use of multivariate approach in the years of 2013 (May and November) and 2014 (May and October). Studied ecoregions had the different geographic position, climate, land-use, and anthropogenic activities, could strongly affect physico-chemical variables of water bodies, which caused to change or regulate in algal biomass composition due to the different response of filamentous species. Besides, biochemical responses of species changed at different sampling times and stations. Multivariate analyses indicated that temperature, heavy metals, and nutrient contents of aquatic systems were found to be major variables driving the spatial and temporal occurrence and biochemical contents of filamentous species. Total protein and pigment production by filamentous algae were high in water bodies having high nutrients, whereas they were low in high heavy metal contents. Amount of malondialdehyde (MDA), H2O2, total thiol group, total phenolic compounds, proline, total carbohydrate, and bioaccumulation of metals by filamentous algae were closely related with heavy metal contents of water bodies, indicated by the multivariate approach. Significant increase in aforementioned biochemical compounds with a distinct range of habitats and sensitive-tolerance to environmental conditions could make them highly valuable indicators.

Biochemical responses of filamentous algae in different aquatic ecosystems in South East Turkey and associated water quality parameters.

To the best of our knowledge, any study about biochemical response of filamentous algae in the complex freshwater ecosystems has not been found in the literature. This study was designed to explore biochemical response of filamentous algae in different water bodies from May 2013 to October 2014, using multivariate approach in the South East of Turkey. Environmental variables were measured in situ: water temperature, oxygen concentration, saturation, conductivity, salinity, pH, redox potential, and total dissolved solid. Chemical variables of aqueous samples and biochemical compounds of filamentous algae were also measured. It was found that geographic position and anthropogenic activities had strong effect on physico-chemical variables of water bodies. Variation in environmental conditions caused change in algal biomass composition due to the different response of filamentous species, also indicated by FTIR analysis. Biochemical responses not only changed from species to species, but also varied for the same species at different sampling time and sampling stations. Multivariate analyses showed that heavy metals, nutrients, and water hardness were found as the important variables governing the temporal and spatial succession and biochemical compounds. Nutrients, especially nitrate, could stimulate pigment and total protein production, whereas high metal content had adverse effects. Amount of malondialdehyde (MDA), H2O2, total thiol groups, total phenolic compounds, proline, total carbohydrate, and metal bioaccumulation by filamentous algae could be closely related with heavy metals in the ecosystems. Significant increase in MDA, H2O2, total thiol group, total phenolic compounds, and proline productions by filamentous algae and chlorosis phenomenon seemed to be an important strategy for alleviating environmental factors-induced oxidative stress as biomarkers.

Biosorption and retention of orthophosphate onto Ca(OH)2-pretreated biomass of Phragmites sp.

The biosorption of phosphorus in the form of orthophosphate (Po) from wastewater using biomass as the sorbent is of potential importance because the Po-loaded biomass could be applied in the agricultural sector as fertilizer and soil conditioner. However, biomass generally displays a very low affinity for Po sorption and therefore biomass surface modification is required. In the present study, the biomass (as model grinded leaves of Phragmites sp. were used) was pretreated with Ca(OH)2 to enhance Po biosorption capacity (qe). The results indicate that the alkaline pretreatment resulted in a modification of surface functional groups. It was concluded that the main sorption mechanisms were ligand exchange and electrostatic attraction. A series of experiments were conducted to investigate the performance of the pretreated biomass for Po uptake under various conditions. Isotherm and thermodynamic studies were also applied and analyzed. The biosorption process was best described by the pseudo-second order kinetic model and Langmuir isotherm, which gave a qmax of 12.27mgP/g at 25°C and pH7. The Ca(OH)2 treated Phragmites biomass applied in this study for Po recovery may present some potential advantages in terms of costs and environmental impact.

A Multivariate Approach to Evaluate Biomass Production, Biochemical Composition and Stress Compounds of Spirulina platensis Cultivated in Wastewater.

The study was performed to investigate the effects of using cow effluent for the cultivation of Spirulina platensis on its biomass production and cell physiology. S. platensis was cultivated in three different cow effluents (CE) used as cultivation medium during 15 days. CE was prepared using dry cow manures, and it was further modified with supplement of NaNO3 (CEN) and NaNO3 + NaCl (CENS). High nitrate value stimulated chlorophyll-a and total protein content of the cyanobacterium and also biomass production in standards medium (SM) and CEN media. Total carbohydrate content of S. platensis grown in CE media was found to be higher (p < 0.05) than that of SM. Productions of biomass and biochemical compounds by the cyanobacterium grown on the CE and SM media were evaluated by using multivariate approach. Conductivity, oxidation reduction potential (ORP), salinity, pH, and TDS played important role (p < 0.01) in the biochemical composition. As an effective explanatory factor, ORP had a significant positive correlation with H2O2, whereas negatively correlated with chlorophyll-α, biomass production, filament length, and proline. Canonical correspondence analysis proposed that biochemical compounds of S. platensis were not only affected by salinity and nutrition of media but also by pH and ORP. The present study indicated that CEN as a low cost model medium had high potential for the production of biomass by S. platensis with high protein content.

Predictive modeling of sorption and desorption of a reactive azo dye by pumpkin husk.

The use of effective disposal of redundant pumpkin husk (PH) to remove pollutants is an important issue for environmental protection and utilization of resource. The aim of this study was to remove a potentially toxic reactive azo dye, Reactive Red (RR) 120, by widespread PH as a low-cost adsorbent. Particle size, adsorbent dose, pH, temperature, initial dye concentration, and contact time affected the sorption process. Amine, amide, hydroxyl, and carboxyl groups of PH played significant roles on the sorption process. Rapid sorption occurred within the first 2 min and equilibrium was reached within 60 min. Sorption kinetic was well represented by logistic equation. Generated secondary logistic model can be used to describe effects of initial dye concentration, contact time, and temperature by a single equation with high R (2) value. Monolayer sorption capacity was found as 98.61 mg g(-1). Activation energy, thermodynamic, and desorption studies showed that this process was physical, endothermic, and spontaneous. This study indicated that redundant PH as a low-cost adsorbent had a great potential for the removal of RR 120 as an alternative eco-friendly process.

Effect of cadmium on biomass, pigmentation, malondialdehyde, and proline of Scenedesmus quadricauda var. longispina.

Effects of cadmium (Cd(2+)) on biomass, pigmentation (chlorophyll a, b, and total carotene), malondialdehyde (MDA), and proline productions by Scenedesmus quadricauda var. longispina were investigated. Cadmium had inhibitory effect on the productions of biomass and pigmentation. Significant differences were found in pigment content among groups. On the other hand, Cd(2+) had a simulative effect on the production of MDA and proline by the alga. FTIR-ATR spectroscopy was used to examine active groups of algal biomass before and after Cd(2+) exposure. Results confirmed that amino, amide, and anionic groups had significant role on the biosorption of Cd(2+) by the alga. Increased accumulation of MDA and proline seemed to be an important strategy for alleviating metal-induced oxidative stress in S. quadricauda var. longispina.