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Copyright of Anbar Journal of Agricultural Sciences is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Seven coal seams were sampled from several mines and outcrops of the Rio Bonito Formation, Bonito and Barro Branco coal seams, in the coal mining region of Criciúma, Paraná Basin, Santa Catarina State (Brazil), for a detailed palynostratigraphic study. The coal seams sampled yield abundant, diverse and moderately to well preserved palynological assemblages. A total of twenty-seven spore species, fourteen pollen species and four microplanktonic or clorophyceae algae and fungi species were identified. The palyno-assemblages recovered in the Bonito and Barro Branco coal seams are assigned to the Vittatina costabilis Interval Zone, Protohaploxypinus goraiensis Subzone of the Paraná Basin, of Asselian? to Artinskian age (Lower Permian). The microflora assemblages identified in these coal seams are very similar in composition, presenting a dominance of arborescent and herbaceous lycophytes. The Barro Branco coal seam shows a relatively higher frequency of algae like composition than in the Bonito coal seam, suggesting a possible fluvial or lagoonal facies influence. • Palynostratigraphy of Rio Bonito Fm., Bonito and Barro Branco coal seams, Paraná Basin, Santa Catarina State, Brazil. • Palynological data and events interpretation through Paraná Basin. • Palyno-assemblages palaeoenvironmental interpretation. [ABSTRACT FROM AUTHOR]

This research article investigates the extraction of bio-oil from Chlorella vulgaris algae which is then subjected to biodiesel production. To evaluate the maximum oil content, four different pretreatment methods and solvent systems were inspected. Among them, maximum oil yield was obtained from ultrasonic pretreated biomass followed by methanol and methyl tertiary butyl ether solvent extraction. Physico-chemical properties of the bio-oil were analyzed as per AOAC Official Methods. The experiments were then designed to determine how variation in different process parameters influences extraction. From these results, kinetic and thermodynamic parameters were also analyzed. The positive values of ΔS and ΔH and the negative value of ΔG indicate that this process is endothermic, irreversible and spontaneous, respectively. The extracted bio-oil was then subjected to acid catalyzed reaction for biodiesel production. A yield of 98.2 wt% biodiesel was obtained at the optimized condition. Fuel properties were analyzed as per ASTM methods. [ABSTRACT FROM AUTHOR]

The article is devoted to the problems of determining quality and safety of extruded feed additive (EFA) with algae. It is used in the production of mixed feed and premixes. It is proved that the safety of finished food products depends on the safety of feed and feed raw materials. The list of conditions for obtaining safe finished products is given. Today traditional methods of analytical chemistry, express and toxicological methods (marking, biotesting) are used for the analysis of feed safety. The expediency of use of brown algae in the composition of feed products is substantiated. The brightest representative of brown algae is Laminaria. The technology of using Laminaria algae in the composition of feed products in the form of extruded feed additive is proposed. The method of determination of organicity by methods of biotesting is given: biocrystallization method, determination of the oxidation-reduction potential index (ORP), organicity using Colpoda steinii culture. Indicators of organicity are given. An analysis of experimental samples biocrystalograms suggests that EFA is environmentally safe and do not endanger the environment or the health and life of animals and humans. When determining the ORP of the EFA with algae it was established that the product is easily digestible, since it has a biological compatibility with the animal organism. The expediency of using the process of extrusion to reduce the toxicity of algae is established. The application of the extrusion allows to add up to 15% Laminaria algae to the feed. The results of biological studies of EFA in vivo are presented, which indicate a high biological efficiency of the use of algal feed supplement in the composition of feed for young farm birds in the amount of up to 25%, since the average daily weight gain of rats increases and the cost of feed decreases. [ABSTRACT FROM AUTHOR]

Seaweeds are accessible and important marine organisms found in coastal zones, which have shown their nutritive potential as food or additive. These organisms are relatively abundant in the coastline of Ecuador, but their biochemical composition has not been adequately studied. Therefore, the aim of this research was to evaluate the proximate composition of seven seaweeds (four red, two brown, and one green) collected from Salinas Bay, Ecuador, as a contribution to the knowledge of the nutritional potential of these organisms that belong to this region. Moisture, ash, fat, fiber and protein contents were determined by standard protocols, while carbohydrates were obtained by difference. Energetic content (or caloric profile) was calculated according to the contributions of macromolecules (fats, proteins and carbohydrates). The parameters in highest proportion found in all species were carbohydrates (32.2-45.5%) and minerals (or ash, 25.8-36.7%), which play a significant role in human nutrition and the food industry. Furthermore, protein, fiber, and fat contents were relatively low, with values around 4.7-8.0%, 0.9-5.0%, and 0.3-3.0%, respectively, indicating these organisms are a good option as healthy food. According to statistical analysis (ANOVA), each nutritive parameter was significantly different among the species (P < 0.05). Results indicate edible seaweeds from Ecuador have potential as nutritious food that could offer between 1 500-2 000 kcal kg-1, which is higher than many common vegetables. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Different conversion processes are required depending on algae composition. • Algae biodiesel N and S content is negligible, unlike algae biocrude which is high in N (5–8%) and S (0.5–1.5%). • N and S content of algal biocrude can be reduced through two-stage HTL and hydrodenitrogenation. • Studies of engine performance and emissions are solely using algae biodiesel. • The effect of N in a biofuel is unclear, so a study is needed. Abstract Nitrogen (N) and sulphur (S) play an important role in algae cultivation as they are important nutrients for its growth. They also affect the conversion route, the product distribution (i.e. yield), elemental and chemical composition of the end products. Hydrothermal liquefaction (HTL) is one of the most suitable processes to convert high-moisture algae to biocrude without drying. The high protein fraction in algae species causes high N (5–8 wt%) and S (0.5–1.5 wt%) in the biocrude. In this review, only two approaches for algae biocrude upgrading for N and S removal were identified from the literature, two-stage HTL and catalytic HTL (e.g. K 2 CO 3 and activated carbon promoted denitrogenation and desulphurization). Most published research presumed that high N content in biocrude will result in high NO x when biocrude is used in a diesel engine. However, NO x emissions are heavily dependent on engine operating conditions as well as on fuel properties and to our knowledge, no study investigated emissions of N-S containing biofuel and the consequent effect on emissions has been done, requiring further study. This review will consider cultivation and harvesting techniques, the conversion routes (especially HTL), the quality of the biofuels and the engine performance and emissions focusing on the role N and S each play. [ABSTRACT FROM AUTHOR]

The joint effect of temperature and irradiance on growth, biochemical composition and antioxidant enzyme activities of the newly isolated Bulgarian Scenedesmus sp. strain BGP was investigated. The strain grew well over the temperature range 16-32°C under two different photon densities -- 132 µmol photons m-2 s-1 (low light intensity) and 2 x 132 µmol photons m-2 s-1 (high light intensity). Higher temperatures (35 and 42°C) suppressed the growth. The optimum conditions for growth and accumulation of lipids and proteins were 25°C and high light intensity. At low light intensity, the suboptimum temperatures promoted the protein synthesis. The carbohydrate content was highest at 30°C and high light intensity. Superoxide dismutase and glutathione reductase activities at 16°C were lower than at the optimum temperature, whereas at 35°C the activities of catalase, glutathione reductase, and one superoxide dismutase isoform were elevated. The substantial growth and balanced biochemical composition over a wide temperature range (16-32°C), as well as the lack of stress response of antioxidant enzymes to low temperature indicated the temperature tolerance of Scenedesmus sp. BGP and its suitability for large-scale cultivation. [ABSTRACT FROM AUTHOR]

Copyright of Baghdad Science Journal is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The high content of lipids in microalgae (>60% w/w in some species) and of carbohydrates in seaweed (up to 75%) have promoted intensive research towards valorisation of algal components for the production of biofuels. However, the exploitation of the carbohydrate fraction to produce a range of chemicals and chemical intermediates with established markets is still limited. These include organic acids (e.g. succinic and lactic acid), alcohols other than bioethanol (e.g. butanol), and biomaterials (e.g. polyhydroxyalkanoates). This review highlights current and potential applications of the marine algal carbohydrate fractions as major C-source for microbial production of biomaterials and building blocks. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the bioaccessibility of toxic elements, including aluminum (Al), arsenic (As), nickel (Ni), cadmium (Cd), and lead (Pb) in five commercial algae consumed by humans in Italy. The degree of bioaccessibility of these elements may have important implications for human health. Simulation of gastrointestinal tract (GIT) digestion was divided into three stages through use of synthetic saliva, gastric, and bile–pancreas solutions. After pre-treatment with a saliva solution, seaweed samples underwent one of the following treatments: (1) simulated gastric digestion only or (2) simulated complete GIT digestion (gastric digestion followed by bile-pancreas digestion). The bioaccessibility of these toxic elements ranged from approximately 5% to 73% and from 4% to 77% in gastric and GIT digestion, respectively. The bioaccessibility of Al and Pb is poor (5–15%), As and Ni were fairly (40–55%), while Cd displayed a high bioaccessibility. No significant differences in toxic elements mobility was found between samples that only underwent gastric digestion compared to those that underwent a complete GIT digestion. [ABSTRACT FROM PUBLISHER]

SUMMARY: Three species of the cosmopolitan genus Ulva (U. paschima, U. chaugulii and U. ohnoi) from the Persian Gulf were identified using morphological and molecular markers, and were analyzed for total lipids, fatty acids, proteins and amino acid profiles. Our results show that the studied Ulva species have high protein content (9−25% dry weight), contain essential fatty acids and nearly all essential amino acids. This suggests Ulva could have potential as a form of human nutrition and animal feed with a low carbon footprint. [ABSTRACT FROM AUTHOR]

To examine the influence of river discharge on phytoplankton composition, time-series observations were conducted at upper, middle and lower Godavari estuary during 2009. The salinity variations in the estuary were depended on freshwater discharge and tidal exchange. River discharge brought a significant amount of nutrients, however it did not induce phytoplankton bloom due to severe light limitation driven by high turbidity. Enhanced phytoplankton biomass and abundance were associated with water column stratification during moderate discharge period, suggesting that water column stability is more important than nutrients to promote phytoplankton blooms. The contribution of diatoms to the total phytoplankton abundance increased with decrease in salinity and vice versa for blue-green algae. The relationship of phytoplankton abundance with salinity and nutrients suggests that low salinity and high N:P ratio favored growth of blue-green algae, whereas high salinity and low N:P/N:Si favored diatoms. This study suggested that discharge brought modification in phytoplankton composition. [ABSTRACT FROM AUTHOR]

The proximate chemical composition of Sargassum horridum was determined monthly, including extract yields of alginate, crude fucoidan, and ethanolic extract. In addition, the biological activity (antioxidant and antibacterial) of the ethanolic extract and anticoagulant activity of the fucoidan were examined. Significant monthly variation was found in the chemical composition (moisture, protein, ash, crude lipids, crude fiber, carbohydrates, and gross energy), as well as in the alginate, fucoidan, and ethanolic extract yields. The maximum yield of crude fucoidan (13.5% dry weight) and alginate (21.4% dry weight) occurred in May. Crude fucoidan increased the clotting time at all concentrations tested during all months, based on activated partial thromboplastin and prothrombin time assays. The maximum yield of ethanolic extract occurred in April and August (6% dry weight). The ethanolic extract was evaluated for free radical scavenging activity using the 2,2-diphenyl-1-picrylhydrazyl method, with the highest reduction percentage in April (53%). Only the extracts from March, July and August showed slight antibacterial activity against Vibrio parahaemolyticus, V. alginolyticus, and Staphylococcus aureus. Sargassum horridum thus represents a potential source of carbohydrates, anticoagulant, antioxidants and antibacterial compounds. The best time of year for harvesting the alga is from May to July. [ABSTRACT FROM AUTHOR]

This review analyzes the state of knowledge on the capacity of Mediterranean macroalgae to accumulate, tolerate and biomonitor macro- and micro-elements present in seawater and sediments. The results show that the investigated macroalgal species amount to c. 5.0% of all Mediterranean native Rhodophyta, Chlorophyta and Ochrophyta. The most commonly analyzed elements in algae were Pb, Cd, Zn and Cu, whereas very few studies were available for macroelements such as Ca and K. Uptake mechanisms and the factors influencing accumulation are overall well known, but the available studies are restricted to a limited number of chemical elements and algal species. This review also shows that macroalgae can accumulate and tolerate high concentrations of chemical elements, and can act as effective bioindicators of marine pollution. Phytotoxic limits for algal species are not clearly identified by the available studies and require further investigation. Future research should focus on the development of protocols for long-term biomonitoring programmes through the use of macroalgae. Future studies also need to investigate the biomagnification of toxic trace elements in macroalgae-based food webs. [ABSTRACT FROM AUTHOR]

In this work we present a simple and cost-effective approach for the determination of selenium species in algae and yeast biomass, based on a combination of thin-layer chromatography (TLC) with diode laser thermal vaporization inductively coupled plasma mass spectrometry (DLTV ICP MS). Extraction of freeze-dried biomass was performed in 4M methanesulphonic acid and the selenium species were vaporized from cellulose TLC plates employing a continuous-wave infrared diode laser with power up to 4 W using a simple laboratory-built apparatus. Selenomethionine and selenocysteine were quantified with limits of detection 3 μg L −1 in a Se-enriched microalgae Chlorella vulgaris and yeast certified reference material SELM-1. Results delivered by TLC-DLTV ICP MS were consistent with those obtained by a routine coupling of high-performance liquid chromatography (HPLC) to ICP MS. In addition, the TLC approach is capable of analyzing extract containing even undiluted crude hydrolysates that could damage HPLC columns. [ABSTRACT FROM AUTHOR]

The microalgae Dunaliella salina is industrially produced due to its high content in carotenoids induced by low nitrogen and high salinity conditions. D. salina with low carotenoids content also produces other added value compounds, however its recovery have hardly been studied. This work aims to examine the potential of pre-concentrating D. salina by membrane processing prior to a final harvesting step by low-shear centrifugation. The aim is to minimize the overall energy expenditure and reduce capital costs, while assuring a minimal loss of cell integrity. This task is challenging, considering the sensitivity of D. salina to shear. Harvesting of D. salina by ultrafiltration allowed reaching a final concentration factor of 5.9, with an average permeate flux of 31 L/(m 2 h). The Total Cost of Ownership and energy consumption for harvesting are respectively 52% and 45% lower when applying a two-step approach with pre-concentration (ultrafiltration) compared to only harvesting by centrifugation. [ABSTRACT FROM AUTHOR]

The Nitellopsis obtusa (N.A.Desvaux) J.Groves cell provides a model system for complex investigation of instantaneous effects of various biologically active compounds (BC) on the generation of plant bioelectrical signals in vivo. Experimental evidence using multiple electrical signals as biomarkers of the effects of BC (acetylcholine, asparagine, glutamate, nicotine, aluminium, nickel and cadmium ions) is provided. The effect of BC on membrane transport systems involved in the cell excitability were tested by current clamp, voltage clamp and patch clamp methods. Membrane potential (MP) alterations and action potential (AP) patterns in response to BC were shown to represent the cell state. High discretisation frequency allows precise, high time resolution analysis of real-time processes measuring changes in excitation threshold, AP amplitude and velocity of repolarisation values after application of BC indicating the effect on ion channels involved in AP generation. Application of voltage clamp revealed that changes in AP peak value were caused not only by increment in averaged maximum amplitude of the Cl– current, but in prolonged Cl– channels' opening time also. The cytoplasmic droplet can serve as a model system in which the effects of BC on single tonoplast ion channel can be studied by patch clamping. Investigation of electrical cell-to-cell communication revealed evidence on the electrical signal transduction through plasmodesmata. [ABSTRACT FROM AUTHOR]

Large resources are being invested globally in algae research in the anticipation that these microorganisms will become the “silver bullets” that lead to economic bio-renewable fuels, new food sources, and a host of high value products and simultaneously mitigate rising atmospheric CO 2 levels. A great deal of research has been completed on strains of algae with the potential to produce high lipid yields that make the biomass suitable for biofuel production. Many production systems for algae cultivation continue to be developed for moderate and hot climates (e.g., USA, Europe, and Australia). The largest algae cultivation systems to date use open pond systems. These autotrophic systems, however, have limited applicability in Canada’s northern climatic conditions. There is consensus that closed photobioreactor systems are required to control environmental conditions (including temperature), minimize evaporation and contamination, and augment the limited sunlight available during winter to generate consistent biomass yields for economically sustainable crops. Given the high capital and operating costs, however, many are skeptical that meaningful and economically sustainable algae cultivation can take place in Canada. This paper identifies nine scalable algae photobioreactor cultivation technologies that may suit Canadian northern climates. The information provides insights related to the developing algae industry in Canada as well as highlighting opportunities for further technological development specific to cold climates. Although the review demonstrates that exciting headway has been made, significant technological challenges remain and require that further innovations be developed. [ABSTRACT FROM AUTHOR]

Microalgae biomass is known as a promising sustainable source of bioactive compounds. Application of microalgae biomass in food and feed products requires information regarding storage stability and optimized storage conditions to minimize unwanted deterioration which downgrades the bioactive composition of microalgae biomass. In order to investigate the worsening of the nutritional quality of freeze dried biomass, a multifactorial storage experiment was conducted on a high EPA (eicosapentaenoic acid) Nannochloropsis salina biomass. The storage time (0-56 days), storage temperature (5, 20, and 40 °C and packaging conditions (under vacuum and ambient pressure) used as main factors. During the 56 days of storage, both time and temperature strongly influenced the oxidation reactions which result in deterioration of bioactive compounds such as carotenoids, tocopherols, and EPA. Lipid deterioration occurred both due to enzyme-induced lipolysis and autoxidation. Carotenoids and α-tocopherol contents decreased during storage, but may still have prevented EPA from higher oxidative deteriorations due to their powerful antioxidant properties. Oxidation reactions, which resulted in the creation of primary and secondary volatile oxidation products, occurred mainly at the first days of storage. The resulting volatile compounds(measured by head space gas chromatography-mass spectrometry) declined further until day 56, probably due to reaction with amino acids, or decomposition to low molecular weight tertiary oxidation compounds. Storage of microalgae at low temperature is more effective than vacuum packaging. Practical Applications: Microalgae are known as a sustainable source of bioactive compounds, and their industrial scale application is growing very fast. Application of microalgae biomass in food, feed, or cosmetics requires the knowledge of the optimum storage conditions to prevent the value-added compounds from deterioration. Results of this study improve our understanding of the chemical deterioration under different storage conditions and can help the producers/customers to extend the shelf life of microalgae biomass by choosing correct storage conditions. The storage time and conditions influenced the bioactive compounds in freeze-dried microalgae biomass. [ABSTRACT FROM AUTHOR]

Effect of various flue gas CO2concentrations (5%, 10% and 14.1%) on growth rate and biochemical properties of a green microalgaScenedesmus obliquuswas investigated.S. obliquusshowed the highest biomass production and growth rate (0.36 g L−1andμmax = 1.00 day−1), total inorganic carbon removal (35.8 mg L−1), lipid productivity (9.9 mg L−1 day) and carbohydrate productivity (10.3 mg L−1 day) with 14.1% CO2after 8 days of cultivation. Fatty acid methyl ester analysis revealed that the palmitic and oleic acid contents were increased up to 5% and 7% with 14.1% CO2, respectively. Application of flue gas CO2enhanced the growth along with lipid and carbohydrate productivity ofS. obliquus, which can be exploited for reducing the CO2concentration. [ABSTRACT FROM AUTHOR]

Seaweed habitats are characterised by constantly fluctuating environmental conditions which can influence the biochemical composition of species. To quantify the natural variability in concentrations and composition of pigments and fatty acids, a seasonal and spatial analysis of ecologically and economically important seaweed species ( Fucus serratus, Ascophyllum nodosum, Himanthalia elongata, Laminaria digitata and Palmaria palmata) from Ireland was undertaken. Results revealed both common and species-specific patterns in seasonal and spatial algal composition. Generally, pigment concentrations decreased during summer months and were associated with a higher ratio of xanthophylls to chlorophylls. A similar response was observed regarding the proportions of polyunsaturated fatty acids (PUFA) which also decreased during summer. Concentrations in total fatty acids (TFA) revealed two distinct patterns in the five species investigated. In the two fucoid species, an increase in TFA during summer months was positively correlated with high proportions of monounsaturated fatty acids, implying an accumulation of storage lipids; in the remaining three species, proportions of PUFA were highest during winter and generally followed the seasonal trends of TFA. On a larger, geographical, scale, results demonstrated an influence of sampling location on pigments and fatty acids. Results highlight the complexity of interacting seasonal, spatial and species-specific drivers determining the biochemical composition of seaweeds which influences their value as food source and should be considered when natural stocks are harvested for high-value commercial applications. [ABSTRACT FROM AUTHOR]

SUMMARY Microalgae are an important source of unsaturated fatty acids, phospholipids, glycolipids, and carotenes, which are useful compounds for the food and pharmaceutical industries. The Atacama Desert of northern Chile is one of the driest deserts on Earth and, as such, it is a great natural laboratory in which to study new microorganisms adapted to extreme environments. A microalgal strain, referred to here as CH03, was isolated from a microbial mat in salt flat water in Salar de Atacama. Genetic analysis of the 18S ribosomal RNA gene showed that the strain had homology with other known sequences of the species Chlorella sorokiniana. Our results revealed the adaptability of this microalga to freshwater medium under laboratory conditions, despite coming from an extremely high-salinity environment. The fatty acid profile of CH03(A) newly isolated in Bold's basal medium differed from that of CH03(B) cultured in vitro in modified F/2 medium and from another five strains of C. sorokiniana and three strains of Chlorella vulgaris in that it had a high stearic acid content and had no polyunsaturated fatty acids. The major biochemical components observed in this strain were proteins (64.3-73.6%) and lipids (26.6-32.6%). This study suggests that the strain CH03 could be a protein source and that this oleaginous microalga is easy to grow in vitro as a biological model for future studies. [ABSTRACT FROM AUTHOR]

This study presents information on the biochemical composition (dry weight basis), nutritional aspects, and angiotensin I-converting enzyme (ACE) inhibitory properties of selected macroalgae ( Ulva compressa, Ulva rigida, Gelidium microdon, and Pterocladiella capillacea) from Azores. Moisture content was very high (83.2% to 90.0% of fresh weight). Total dietary fiber (33.7% to 41.0%) that presented a good balance of both soluble and insoluble fibers (15.5% to 19.2% and 18.2% to 21.8%, respectively) was the most abundant component in these macroalgae. Protein and ash (ranged from 15.7% to 23.4% and 10.7% to 20.7%, respectively) were the 2nd most abundant components in red and green macroalgae, respectively. Moderate soluble carbohydrate contents (14.5% to 19.8%) were found in all species. Lipid contents were low (1.0% to 4.3%), particularly in Ulva species (1.0% to 1.7%), but contained higher unsaturated fatty acids (FAs) (7.5% to 32.9% and 29.6% to 69.2% of total FA for monounsaturated fatty acid and polyunsaturated fatty acid groups, respectively) than saturated fatty acid (23.3% to 46.8% of total FA) contents. All the macroalgal proteins had high digestibility in vitro (82.2% to 89.4%, relatively to sodium caseinate), contained high quantity of essential amino acids (45.3% to 58.1% of total amino acids), but in different proportions, and were rich in aspartic and glutamic acids that together account for 17.2% to 36.2% of the total amino acids. These results suggested that regular consumption of the selected macroalgae may improve human health and revealed that they can be used for producing food supplements for human and animal nutrition and/or pharmaceuticals with potential effect on the regional economy. Furthermore, the ACE-inhibitory IC50 values of 0.095 to 0.695 mg/mL for the <1 kDa protein hydrolysate fraction revealed a potential impact on hypertension disorder. [ABSTRACT FROM AUTHOR]

The pollen and algae records derived from core KCES-1 in the East Sea (Japan Sea) reveal vegetation and climate changes during the past 44 ka. From 44 to 36 cal ka BP, forest vegetation in the coastal regions of Ulleung Basin was composed predominantly of subalpine conifer forest, open grassland covered the exposed continental shelves, indicating a cool and dry climate. During the period of 36–28.3 cal ka BP, a warmer and wetter climate caused the contraction of subalpine conifer forest in the coastal regions of Ulleung Basin, and the expansion of marsh in the exposed continental shelves. From 28.3 to 17.6 cal ka BP, the sea-level decline restricted the herbs pollen originates in the exposed shelf of East China Sea and Yellow Sea inflow into the East Sea (Japan Sea), and caused the reduction of herbs pollen in the site location. During the time interval of 17.6–15.1 cal ka BP, a great expansion of subalpine conifer forest can be regarded as the consequence of enhanced East Asian winter monsoon (EAWM). The obvious increase in temperate deciduous broadleaved trees, spores and algae can be attributable to the rising of sea level and the warming of climate from 15.1 to 12.1 cal ka BP. During the period of 12.1 to 5.3 cal ka BP, broadleaved taxa increased, especially during the time period of 9.5–5.3 cal ka BP, evergreen broadleaved trees pollen reach the highest values throughout the core, as a result of the Holocene climate optimum condition. Vegetation changes controlled by humid impacts occurred at the late Holocene, as indicated by an increase in Pinus pollen. [ABSTRACT FROM AUTHOR]

This study evaluated the impact of dissolved organic matter (DOM) of varying molecule weights (MWs) on long-term exposure to Cu and Pb in Chlorella pyrenoidosa . Citric acid, fulvic acid, and humic acid, in the order of increasing MWs, were selected to represent DOM. The results showed that DOM with larger MWs had stronger inhibitory effects on the bioavailability of Cu to algae. However, the biosorption isotherm of Pb in the presence of DOM was different: as Pb equilibrium concentration increased, the biosorption capacity increased sharply to a maximum, then decreased. The maximum values ranged between 0.186 and 0.398 mmol g −1 , as the solution DOM concentration and MW changed, exhibiting a stoichiometric relationship between DOM, Pb and algae. The ternary complex of Pb-DOM-alga formed in a limited Pb concentration range, and increased the percentage of internalized Pb. This research helps to understand the role of DOM in metal uptake in phytoplankton. [ABSTRACT FROM AUTHOR]

SUMMARY Previous experiments with a factorial design have revealed the effects of several environmental factors on species performance and their interactions, which indicate synergistic or antagonistic effects. Temperature, nutrient availability, and irradiance are well-known environmental factors that affect the growth and chemical composition of brown algae. However, relatively few studies have tested their combined effect on brown algal growth and chemical composition using a three-way factorial design. We conducted a culture experiment to test the combined effects of elevated summer temperatures (23 and 26°C), irradiance (180 and 30 μmol photon m−2 s−1), and nutrient availability (enriched and non-enriched seawater) on four relative growth rates ( RGRs; based on wet weight, blade width, length, and area) and three chemical compositions (including carbon, nitrogen, and phlorotannin content) in juvenile sporophytes of the kelp Eisenia bicyclis. RGR based on blade width was the most sensitive to abiotic factors among all RGRs. A significant interaction between temperature and nutrient availability on this RGR suggested that the negative effect of elevated temperature was antagonized by a reduction in nutrient availability. Similarly, the positive effect of elevated irradiance on carbon content was synergized by reduced nutrient availability. Moreover, the negative effect of increased irradiance on nitrogen content was antagonized by elevated temperature in nutrient-enriched treatments, but not in non-enriched treatments. The content of carbon-based phlorotannins increased with reduced nutrient availability but not with elevated irradiance. These results suggest that these abiotic factors have complex interactions on the growth and chemical composition of this species. [ABSTRACT FROM AUTHOR]

Transcriptome sequencing and annotation was performed on Haematococcus pluvialis mutant red cells induced with high light under 15% CO 2 to demonstrate why astaxanthin yield of the mutant was 1.7 times higher than that of a wild strain. It was found that 56% of 1947 differentially expressed genes were upregulated in mutant cells. Most significant differences were found in unigenes related to photosynthesis, carotenoid biosynthesis and fatty acid biosynthesis pathways. The pyruvate kinase increased by 3.5-fold in mutant cells. Thus, more pyruvate, which was beneficial to carotenoids and fatty acid biosynthesis, was generated. Phytoene synthase, zeta-carotene desaturase, lycopene beta-cyclase involved in β-carotene biosynthesis in mutant cells were upregulated by 10.4-, 4.4-, and 5.8-fold, respectively. Beta-carotene 3-hydroxylase catalyzing conversion of β-carotene into astaxanthin was upregulated by 18.4-fold. The fatty acid biosynthesis was promoted because of the upregulation of acetyl-CoA synthetase and acetyl-CoA carboxylase, thus increasing astaxanthin esterification and accumulation in mutant cells. [ABSTRACT FROM AUTHOR]

Natural antioxidants from sustainable sources are favoured to accommodate worldwide antioxidant demand. In addition to bioprospecting for natural and sustainable antioxidant sources, this study aimed to investigate the relationship between the bioactives ( i.e. carotenoid and phenolic acids) and the antioxidant capacities in fucoxanthin‐producing algae. Total carotenoid, phenolic acid, fucoxanthin contents and fatty acid profile of six species of algae (five microalgae and one macroalga) were quantified followed by bioactivity evaluation using four antioxidant assays. Chaetoceros calcitrans and Isochrysis galbana displayed the highest antioxidant activity, followed by Odontella sinensis and Skeletonema costatum which showed moderate bioactivities. Phaeodactylum tricornutum and Saccharina japonica exhibited the least antioxidant activities amongst the algae species examined. Pearson correlation and multiple linear regression showed that both carotenoids and phenolic acids were significantly correlated (p < 0.05) with the antioxidant activities, indicating the influence of these bioactives on the algal antioxidant capacities. [ABSTRACT FROM AUTHOR]

Evaluations of the composition and biomass of photoautotrophic periphyton, nutrient concentrations of water, and concentrations of total phosphorous of benthic organic matter at eight stream sites in Middle Tennessee were used to: (1) document the composition of soft-algae and diatom assemblages, (2) assess the trophic state of the stream sites, (3) correlate trophic state to percent composition of soft-algae taxa, and (4) construct biotic indices using soft-algae taxa to help monitor trophic state. The concentration of total phosphorous of benthic organic matter was a more accurate indicator of the trophic state of the stream sites we studied relative to nutrient concentrations of water as demonstrated by correlation coefficients for nutrient concentrations to benthic concentrations of chlorophylla, ash-free dry mass of benthic organic matter, and biotic indices which denote trophic state using diatom and soft-algae taxa. The algae trophic index developed using soft-algae taxa abundance-weighted averages of benthic concentrations of chlorophyllacorrelates significantly to all of the benthic characteristics used to denote trophic state. This index is the first to utilize periphyton characteristics, as opposed to nutrient concentrations of water, to assign trophic-indicator values to soft-algae taxa in lotic systems and does not require a computer program to compute. [ABSTRACT FROM AUTHOR]

The suspended algal fraction in small lotic waterbodies has rarely been investigated as the ecological importance was questioned due to low abundances. Recent findings suggest, that substantial riverine plankton communities can establish in small lotic waterbodies. The gap of knowledge concerning the composition of suspended algal assemblages and influential factors determining their composition is addressed in this study by monitoring suspended and attached algal communities over a two year period in agriculturally influenced small lotic waterbodies using delayed fluorescence spectroscopy. A quantitative comparison of suspended and attached algae indicated, that suspended algae exceeded attached algal biomass in late summer and early autumn. Redundancy analyses and corresponding generalized linear models indicated that the suspended algal groups were most influenced by nutrients, temperature and velocity, whereas light regime was of minor importance. The attached algal groups were affected by the same factors, however with differing intensity. Regional factors, such as season, were identified as the major gradients along which both algal fractions varied, inducing temporal synchronous algal assemblages. This work represents a contribution towards a better understanding of algal ecology specifically suspended algae in small lotic waterbodies. [ABSTRACT FROM AUTHOR]

Polar microalgae live under extreme environmental conditions: permanently low temperatures (−1.7°C to +5°C) and extreme variations in irradiance and day length. These conditions may have led to various specific adaptations allowing Arctic phytoplankton to become specialists under these conditions. The goal of this study is to derive, for polar microalgae, empirical relationships between key physiological parameters (growth rate, photosynthesis-irradiance curve parameters, Chl a : C, and N : C ratios) and growth temperature and irradiance in nutrient replete cultures. Ecophysiological characteristics of polar and temperate microalgae were also compared in order to highlight some strategies that are specific to the polar environment. Most of the polar species are psychrophilic. Polar microalgae have low light-saturated growth rates (μm) and very low light saturation parameters for growth ( KE) but similar initial slopes of their growth-irradiance curve ( αµ = μm/ KE). Low temperatures probably account for low μm and KE in polar species. The C : Chl a ratios ( θ) of polar species are similar to those of temperate species although they have much lower growth rates, which implies major differences in energy allocation. Polar microalgae also exhibit very unique photosynthetic properties [low light saturation parameters for photosynthesis ( EK), low maximum photosynthetic rates ( [ABSTRACT FROM AUTHOR]

The aim of this study is to determinate optimal model parameters for prediction of long-term forward (>1 month) chlorophyll-a (Chl-a) concentration in lakes. To optimize model parameters, water quality data from 93 lakes in South Korea were collected and analyzed. Among the 93 lakes, 30 problematic lakes were selected as study sites. Correlation analysis using Chl-a and other water quality data were conducted, and the results indicated that electrical conductivity (EC) and turbidity are important key parameters, which are less considerable than in previous research. To verify effectiveness of the selected parameters, one-month forward prediction of Chl-a concentration was performed using water quality data from the most problematic lakes in South Korea. Artificial neural networks were used as a prediction model. The results of Chl-a prediction using selected parameters showed higher accuracy compare to using general parameters based on the literature reviews. EC and turbidity are important parameters, showing high correlation with Chl-a. This study will corroborate effective model parameters to predict long-term Chl-a concentration in lakes. [ABSTRACT FROM AUTHOR]

The apparent Henry’s Law constant (H′), which quantifies the concentration partition of a gas-liquid equilibrium of carbon dioxide (CO2), is used to optimize the absorption of carbon dioxide in algae liquors. The values of H′ were examined under various conditions: in water at different temperatures (27 and 37°C), in alkaline buffering chemicals (sodium hydroxide (NaOH) and sodium carbonate (Na2CO3)), and in aquatic algae plants (Egeria densa and Anubias barteri nana). The optimal conditions for CO2 absorption can be obtained by controlling the aqueous pH values (around weak alkalinity with pH 9-10) using sodium carbonate as an alkaline buffering chemical at 27°C, yielding exact H′ values of around 16.3–21.3 atm/M, which were obtained from the mean gaseous CO2 concentration of 803 ppm and the total aqueous carbonate concentration of 4.085 mg/L. The experimental results reveal that an alkaline buffering compound, sodium carbonate, can be added to water to maintain a constant aqueous alkalinity enough for the fixation of carbon dioxide by the photosynthesis of green algae in a photobioreactor. [ABSTRACT FROM AUTHOR]

In the naturally iron-fertilized surface waters of the northern Kerguelen Plateau region, the early spring diatom community composition and contribution to plankton carbon biomass were investigated and compared with the high nutrient, low chlorophyll (HNLC) surrounding waters. The large iron-induced blooms were dominated by small diatom species belonging to the genera Chaetoceros (Hyalochaete) and Thalassiosira, which rapidly responded to the onset of favorable light-conditions in the meander of the Polar Front. In comparison, the iron-limited HNLC area was typically characterized by autotrophic nanoeukaryote-dominated communities and by larger and more heavily silicified diatom species (e.g. Fragilariopsis spp.). Our results support the hypothesis that diatoms are valuable vectors of carbon export to depth in naturally iron-fertilized systems of the Southern Ocean. Furthermore, our results corroborate observations of the exported diatom assemblage from a sediment trap deployed in the iron-fertilized area, whereby the dominant Chaetoceros (Hyalochaete) cells were less efficiently exported than the less abundant, yet heavily silicified, cells of Thalassionema nitzschioides and Fragilariopsis kerguelensis. Our observations emphasize the strong influence of species-specific diatom cell properties combined with trophic interactions on matter export efficiency, and illustrate the tight link between the specific composition of phytoplankton communities and the biogeochemical properties characterizing the study area. [ABSTRACT FROM AUTHOR]

Ascophyllum nodosum , an abundant Irish brown seaweed, shows significant seasonal variation in chemical composition and biogas production. The polyphenol content is shown to be a more important factor in biogas production than ash content. High polyphenol content in summer months adversely affected biogas production; suggesting two potential harvest dates, March and October. A. nodosum harvested in October showed a relatively low level of polyphenols (2% of TS) and ash (23% of volatile solids), and exhibited a specific methane yield of 215 L CH 4 kg VS −1 , which was 44% of theoretical yield. The highest yield per wet weight of 47 m 3 CH 4 t −1 was achieved in October, which is 2.9 times higher than the lowest value (16 m 3 CH 4 t −1 ), obtained in December. The gross energy yield of A. nodosum based on the optimal biogas production can achieve 116 GJ ha −1 yr −1 in October. [ABSTRACT FROM AUTHOR]

Nitrogen is one of the most critical nutrients affecting cell growth and biochemical composition of microalgae, ultimately determining the lipid or carbohydrate productivity for biofuels. In order to investigate the effect of nitrogen sources on the cell growth and biochemical composition of the marine microalga Tetraselmis sp., nine different N sources, including NaNO3, KNO3, NH4NO3, NH4HCO3, NH4Cl, CH3COONH4, urea, glycine, and yeast extract were compared at the given concentration of 8.82 mM. Higher biomass concentration was achieved under organic nitrogen sources, such as yeast extract (2.23 g L-1) and glycine (1.62 g L-1), compared to nitrate- (1.45 g L-1) or ammonium-N (0.98 g L-1). All ammonium sources showed an inhibition of cell growth, but accumulated higher lipids, showing a maximum content of 28.3% in ammonium bicarbonate. When Tetraselmis sp. was cultivated using yeast extract, the highest lipid productivity of 36.0 mg L-1 d-1 was achieved, followed by glycine 21.5 mg L-1 d-1 and nitrate 19.9 mg L-1 d-1. Ammonium bicarbonate resulted in the lowest lipid productivity of 14.4 mg L-1 d-1. The major fatty acids in Tetraselmis sp. were palmitic, oleic, linoleic and linolenic acids, regardless of the nutritional compositions, indicating the suitability of this species for biodiesel production. [ABSTRACT FROM AUTHOR]

Long chain n -alkanes (C 27 –C 33 ) in lake sediment records are commonly considered to be terrestrial plant biomarkers when reconstructing paleoclimatic and paleolimnological history. However, the extent to which their accumulation is influenced by n -alkanes originating from algae and submerged plants is largely unclear. Furthermore, to our knowledge, few studies have systematically analyzed the variation in n -alkane concentration or distributions between different submerged plant and algal species. We systematically investigated the n -alkane distributions of 13 algae (including 10 Cladophora and 3 Spirogyra ), 68 submerged plants (including 37 Potamogeton , 7 Myriophyllum , 4 Ruppiaceae and 20 Chara ) and 13 terrestrial plants (including 7 grasses and 6 shrubs) from 16 Qinghai-Tibetan Plateau lakes. The results indicate that the total n -alkane (C 21 –C 33 ) concentration varied between different submerged plants. Potamogeton , Myriophyllum and Ruppiaceae exhibited high concentration, with average values 235.8, 295.9 and 275.9 μg/g, respectively. These values were slightly higher than the concentrations found in terrestrial plant leaves (avg. 206.4 μg/g), whereas the average concentration in Chara was only 2.0 μg/g, significantly lower than that of other submerged plants. Similarly, the concentration in algae was also very low, with average values of 2.0 μg/g and 4.0 μg/g for Cladophora and Spirogyra , respectively. Submerged plant and algal long chain (C 27 –C 33 ) alkanes accounted for a large proportion of the total C 21 –C 33 n -alkanes, with average ratios (long chain vs. total n -alkanes) of 20, 3, 22 and 27% for Potamogeton , Myriophyllum , Ruppiaceae and Chara , respectively. Cladophora and Spirogyra exhibited average ratios of 34% and 65%, respectively. Therefore, submerged plant long chain n -alkane contributions to lacustrine sediments, especially those of Potamogeton and Ruppiaceae , should not be considered negligible due to their high n -alkane concentration. Conversely, some algae, such as Cladophora and Spirogyra , minimally contributed n -alkanes to the lake sediments. [ABSTRACT FROM AUTHOR]

Herbicides play an important role in agricultural practices but the introduction of these compounds into the aquatic environment can have severe consequences for non-target organisms such as microalgae. The ubiquitous green freshwater microalga Chlamydomonas reinhardtii, a model species in all aspects of microalgal physiology, was used to assess the toxicity of atrazine, one of the most widely used herbicides throughout the world. Atrazine acts on photosynthesis and therefore can affect non-target primary producers, such as microalgae. Growth, dry weight, elemental composition, photosynthetic pigments and protein contents and nitrate reductase activity were studied. After 96 h of exposure to different atrazine concentrations all the parameters studied were affected, but different sensitivities to the herbicide were shown. Nitrate reductase (NR) activity was strongly affected even at an atrazine concentration that did not affect growth (0.1 μM); the lowest concentrations of atrazine assayed (0.1 and 0.25 μM) provoked a > 40% decrease in NR activity and NR decreased > 80% with atrazine concentrations of 0.5 μM. C/N ratio was also affected by all the atrazine concentrations assayed. Nitrate reductase activity and C/N ratio were better indicators of the cellular stress state than data on other biochemical components or growth rate. Among cell parameters assayed, the NR activity stood out as a sensitive cytotoxicity endpoint and the activity of this enzyme can be suggested as a sensitive biomarker of stress induced by atrazine in C. reinhardtii. [ABSTRACT FROM AUTHOR]

In general, epiphytes have detrimental effects on the growth of their basiphytes due to competition for light and nutrients. Therefore, basiphyte species must expend energy suppressing epiphytes. Some studies suggest that phlorotannins, i.e. brown algal polyphenols, prevent colonization by epiphytes, whereas others question their allelopathic function because there is not necessarily a negative correlation between epiphyte abundance and the phlorotannin content of the basiphyte algae. Various phlorotannin components are found in brown algal species, thus we hypothesized that the antifouling activities of polyphenolic compounds may differ and that the analysis of phlorotannin profiles could be useful for estimating their ecological functions. We surveyed the epiphyte richness in the apical portions of 373 thalli from 15 sargassacean species, demonstrating that the variation and abundance of epiphyte species differed remarkably among the basiphyte species. However, there was a weak negative correlation between the density and total phlorotannin content of the basiphyte algae in only one of the 18 epiphyte species. The interspecific differences in the phlorotannin profile were characterized by quantitative ¹H nuclear magnetic resonance spectroscopy (qNMR), and four major groups were categorized based on cluster and principal component analyses of polyphenolic signals in the qNMR spectra. The epiphyte Neosiphonia harveyi was more abundant on Sargassum hemiphyllum, S. patens and S. piluliferum than on other basiphyte species, and these three species were similar according to the cluster analysis. These results suggest that some phlorotannin components may be more effective for antifouling; thus interspecific differences in the phlorotannin profile could affect the variation and abundance of epiphytes. [ABSTRACT FROM AUTHOR]

Microalgae can contribute to a balanced diet because of their composition. Beside numerous essential nutrients, carotenoids are in the focus for food applications. The bioavailability of carotenoids from photoautotrophic-cultivatedChlorella vulgaris(C. vulgaris) andChlamydomonas reinhardtii(C. reinhardtii) was compared. Anin vitrodigestion model was used to investigate carotenoid bioaccessibility. Furthermore, the effect of sonication on bioaccessibility was assessed. Lutein was the main carotenoid in both species.C. reinhardtiishowed higher amounts of lutein and β-carotene thanC. vulgaris. In contrast toC. reinhardtii, no β-carotene and only 7% of lutein were bioaccessible in nonsonicatedC. vulgaris.Sonication increased the bioaccessibility of carotenoids fromC. vulgaristo a level comparable withC. reinhardtii(β-carotene: ≥ 10%; lutein: ≥ 15%). Thus,C. reinhardtiirepresents a good carotenoid source for potential use in foods without processing, while the application of processing methods, like sonication, is necessary forC. vulgaris. [ABSTRACT FROM AUTHOR]

The new name Neosergipea M. Cáceres, Ertz & Aptroot is introduced to replace Sergipea M. Cáceres, Ertz & Aptroot, which is a later homonym of Sergipea Regali, Uesugui & Santos, a genus of fossil pollen. Using the small subunit of the mitochondrial rDNA cistron, we present an updated phylogeny of the Enterographa clade in Roccellaceae which includes the genera Dichosporidium, Enterographa, Erythrodecton, Mazosia, and Neosergipea. While in a previous analysis the relationship between Neosergipea and Dichosporidium was unresolved, our results suggest Neosergipea to be an unsupported sister to Dichosporidium s. lat. The latter potentially represents two distinct genera, differing in ascospore type. [ABSTRACT FROM PUBLISHER]

Filamentous green algae of the genus Zygnema (Zygnematophyceae, Streptophyta) are key components of polar hydro-terrestrial mats where they face various stressors including UV irradiation, freezing, desiccation and osmotic stress. Their vegetative cells can develop into pre-akinetes, i.e. reserve-rich, mature cells. We investigated lipid accumulation and fatty acid (FA) composition upon pre-akinete formation in an Arctic and an Antarctic Zygnema strain using transmission electron microscopy and gas chromatography coupled with mass spectrometry. Pre-akinetes formed after 9 weeks of cultivation in nitrogen-free medium, which was accompanied by massive accumulation of lipid bodies. The composition of FAs was similar in both strains, and a-linolenic acid (C18:3) dominated in young vegetative cells. Pre-akinete formation coincided with a significant change in FA composition. Oleic (C18:1) and linoleic (C18:2) acid increased the most (up to 17- and 8-fold, respectively). Small amounts of long-chain polyunsaturated FAs were also detected, e.g. arachidonic (C20:4) and eicosapentaenoic (C20:5) acid. Pre-akinetes exposed to desiccation at 86% relative humidity were able to recover maximum quantum yield of photosystem II, but desiccation had no major effect on FA composition. The results are discussed with regard to the capability of Zygnema spp. to thrive in extreme conditions. [ABSTRACT FROM AUTHOR]

Floating debris provides substrates for dispersal of organisms by ocean currents, including algae that thrive on plastics. The 2011 earthquake and tsunami in Tohuku, Japan resulted in large amounts of debris carried by the North Pacific Current to North America from 2012 to 2016. In 2015-2016, the plastics in the debris bore a complex biota including pink algal crusts. One sample (JAW4874) was isolated into culture and a three-gene phylogeny (psbA, rbcL, and SSU) indicated it was an unknown member of the red algal class Stylonematophyceae. It is a small pulvinate crust of radiating, branched, uniseriate filaments with cells containing a single centrally suspended nucleus and a single purple to pink, multi-lobed, parietal plastid lacking a pyrenoid. Cells can be released as spores that attach and germinate to form straight filaments by transverse apical cell divisions, and subsequent longitudinal and oblique intercalary divisions produce masses of lateral branches. This alga is named Tsunamia transpacifica gen. nov. et sp. nov. Sequencing of additional samples of red algal crusts on plastics revealed another undescribed Stylonematophycean species, suggesting that these algae may be frequent on drift oceanic plastics. [ABSTRACT FROM AUTHOR]

Carotenoid composition is very diverse in Rhodophyta. In this study, we investigated whether this variation is related to the phylogeny of this group. Rhodophyta consists of seven classes, and they can be divided into two groups on the basis of their morphology. The unicellular group (Cyanidiophyceae, Porphyridiophyceae, Rhodellophyceae, and Stylonematophyceae) contained only β-carotene and zeaxanthin, ' ZEA-type carotenoids.' In contrast, within the macrophytic group (Bangiophyceae, Compsopogonophyceae, and Florideophyceae), Compsopogonophyceae contained antheraxanthin in addition to ZEA-type carotenoids, ' ANT-type carotenoids,' whereas Bangiophyceae contained α-carotene and lutein along with ZEA-type carotenoids, ' LUT-type carotenoids.' Florideophyceae is divided into five subclasses. Ahnfeltiophycidae, Hildenbrandiophycidae, and Nemaliophycidae contained LUT-type carotenoids. In Corallinophycidae, Hapalidiales and Lithophylloideae in Corallinales contained LUT-type carotenoids, whereas Corallinoideae in Corallinales contained ANT-type carotenoids. In Rhodymeniophycidae, most orders contained LUT-type carotenoids; however, only Gracilariales contained ANT-type carotenoids. There is a clear relationship between carotenoid composition and phylogenetics in Rhodophyta. Furthermore, we searched open genome databases of several red algae for references to the synthetic enzymes of the carotenoid types detected in this study. β-Carotene and zeaxanthin might be synthesized from lycopene, as in land plants. Antheraxanthin might require zeaxanthin epoxydase, whereas α-carotene and lutein might require two additional enzymes, as in land plants. Furthermore, Glaucophyta contained ZEA-type carotenoids, and Cryptophyta contained β-carotene, α-carotene, and alloxanthin, whose acetylenic group might be synthesized from zeaxanthin by an unknown enzyme. Therefore, we conclude that the presence or absence of the four enzymes is related to diversification of carotenoid composition in these three phyla. [ABSTRACT FROM AUTHOR]

The effects of solar UV radiation on mycosporine-like amino acids ( MAAs), growth, photosynthetic pigments (Chl a, phycobiliproteins), soluble proteins ( SP), and C and N content of Mazzaella laminarioides tetrasporophytes and gametophytes were investigated. Apical segments of tetrasporophytes and gametophytes were exposed to solar radiation under three treatments ( PAR [P], PAR+ UVA [ PA], and PAR+ UVA+ UVB [ PAB]) during 18 d in spring 2009, Punta Arenas, Chile. Samples were taken after 2, 6, 12, and 18 d of solar radiation exposure. Most of the parameters assessed on M. laminarioides were significantly influenced by the radiation treatment, and both gametophytes and tetrasporophytes seemed to respond differently when exposed to high UV radiation. The two main effects promoted by UV radiation were: (i) higher synthesis of MAAs in gametophytes than tetrasporophytes at 2 d, and (ii) a decrease in phycoerythrin, phycocyanin, and SPs, but an increase in MAA content in tetrasporophytes at 6 and 12 d of culture. Despite some changes that were observed in biochemical parameters in both tetrasporophytes and gametophytes of M. laminarioides when exposed to UVB radiation, these changes did not promote deleterious effects that might interfere with the growth in the long term (18 d). The tolerance and resistance of M. laminarioides to higher UV irradiance were expected, as this intertidal species is exposed to variation in solar radiation, especially during low tide. [ABSTRACT FROM AUTHOR]

Research on multi-scale temporal dynamics of lotic algal assemblages remains scarce. In this study, we analyzed epilithic algae sampled monthly from a Chinese subtropical mountain river network from 2004 to 2007, by using a multivariate time series modeling approach. We hypothesized that (1) multi-scale temporal dynamics exist within algal communities; (2) physical and chemical conditions drive algal temporal dynamics; and (3) tributary sites differ in algal temporal changes. This study revealed 2-4 site-specific algal temporal dynamics, contributed by 23-45% component taxa. Among the time-related taxa, percentages of high profile guild taxa were higher than both the low profile and the motile guild taxa. Several algal temporal dynamics were found to be driven by water temperature, conductivity, or current velocity, within which influences of conductivity at two sites resulted in directional changes in algal communities. Furthermore, tributary sites differed in algal temporal changes when compared to the two mainstream sites. Our findings imply that natural fluctuations and agricultural disturbance together shaped algal temporal dynamics in the studied river network. In conclusion, for accurately tracking algal temporal dynamics, we recommend that long-term and high-frequency biomonitoring protocols are developed. Moreover, both the mainstream and tributary sites should be monitored simultaneously. [ABSTRACT FROM AUTHOR]

We have performed morphological and crystallographic studies of Braarudosphaera bigelowii using various light and electron microscopy techniques. A study by light microscopy revealed that B. bigelowii has a haptonema, and can use it for adhesion to external substrates. A study of the pentaliths by transmission electron microscopy indicates that the well-known trapezoidal lamina is formed with foliate crystals having perfectly identical crystallographic orientation. A cytological study shows that the pentaliths of B. bigelowii are surrounded by an organic structure consisting of a pentalith-substrate and thin organic layers. The pentalith-substrate underlies the proximal surface of the pentaliths and extends between the sides of the individual pentaliths, it also extends between the five trapezoidal segments forming a pentalith. Thin organic layers, which apparently originate from ridges of pentalith-substrate, cover the distal surface of the trapezoidal segments. The close association between the pentalith-substrate, organic layers, and pentaliths leads us to the hypothesis that calcification of the pentaliths occurs between the pentalith-substrate and organic layers, extracellularly. The relatively high Mg content observed in pentaliths supports our hypothesis of extracellular calcification. [ABSTRACT FROM AUTHOR]

In this study, brown macro-algae harvested from the north coast of Portugal, Laminaria hyperborea , Fucus spiralis , Pelvetia caniculata and Ascophyllum nodosum , were used as natural cation exchangers for the treatment of zinc-containing rinse waters generated in the galvanizing process. The zinc wastewater is characterized by a high conductivity (1.5 mS/cm), a low organic content and a zinc concentration of 10 mg/L, being approximately 80% and 20% in the form of Zn 2+ and ZnSO 4(aq) , respectively. Although the ion-exchange capacity of the four macro-algae is similar (2.2–2.4 mEq/g), mainly associated with the presence of weak acidic carboxylic and strong acidic sulfonic groups, L. hyperborea showed a higher selectivity for zinc ions. The uptake capacity for zinc ions is highly affected by the galvanic wastewater matrix, when compared with the performance using a pure zinc solution. Zinc uptake equilibrium, on all the natural cation exchangers, was well described by a linear relationship. Cation exchange kinetic was adequately represented by a mass transfer model, considering a linear driving force model for intraparticle diffusion. Na-loaded alga showed a higher affinity for zinc ions when compared with Ca-loaded alga and raw alga. HCl, HNO 3 , H 2 SO 4 and CaCl 2 eluents were tested for zinc displacement from exhausted algae. HNO 3 reached an elution efficiency of 100% in less time than the other eluents tested. After the acid elution, the resin was converted to Na or Ca form (Na- or Ca-H-loaded biomass), using NaCl and CaCl 2 solutions. Although the regenerated alga in the form of sodium showed a higher affinity for zinc ions, its physical deterioration after Na loading may affect its application in a full-scale treatment. [ABSTRACT FROM AUTHOR]

Diatoms are widespread in aquatic ecosystems where they may be limited by the supply of inorganic carbon. Their carbon dioxide-concentrating mechanisms ( CCMs) involving transporters and carbonic anhydrases ( CAs) are well known, but the contribution of a biochemical CCM involving C4 metabolism is contentious., The CCM(s) present in the marine-centric diatom, Thalassiosira pseudonana, were studied in cells exposed to high or low concentrations of CO2, using a range of approaches., At low CO2, cells possessed a CCM based on active uptake of CO2 (70% contribution) and bicarbonate, while at high CO2, cells were restricted to CO2. CA was highly and rapidly activated on transfer to low CO2 and played a key role because inhibition of external CA produced uptake kinetics similar to cells grown at high CO2. The activities of phosphoenolpyruvate ( PEP) carboxylase ( PEPC) and the PEP-regenerating enzyme, pyruvate phosphate dikinase ( PPDK), were lower in cells grown at low than at high CO2. The ratios of PEPC and PPDK to ribulose bisphosphate carboxylase were substantially lower than 1, even at low CO2., Our data suggest that the kinetic properties of this species results from a biophysical CCM and not from C4 type metabolism. [ABSTRACT FROM AUTHOR]