Photosynthetic response to a winter heatwave in leading and trailing edge populations of the intertidal red alga Corallina offi-cinalis(Rhodophyta)

Marine heatwaves(MHWs)caused by anthropogenic climate change are becoming a key driver of change at the ecosystem level.Thermal conditions experienced by marine organisms across their distribution,particularly towards the equator,are likely to approach their physiological limits,resulting in extensive mortality and subsequent changes at the population level.Populations at the margins of their species’distribution are thought to be more sensitive to climate-induced environmental pressures than central populations,but our understanding of variability in fitness-related physiological traits in trailing versus leading-edge populations is limited.In a laboratory simulation study,we tested whether two leading(Iceland)and two trailing(Spain)peripheral populations of the intertidal macroalga Corallina officinalis display different levels of maximum potential quantum efficiency(Fv/Fm)resilience to current and future winter MHWs scenarios.Our study revealed that ongoing and future local winter MHWs will not negatively affect leading-edge populations of C.officinalis,which exhibited stable photosynthetic efficiency throughout the study.Trailing edge populations showed a positive though non-significant trend in photosynthetic efficiency throughout winter MHWs exposure.Poleward and equatorward populations did not produce significantly different results,with winter MHWs having no negative affect on Fv/Fm of either population.Additionally,we found no long-term regional or population-level influence of a winter MHWs on this species’photosynthetic efficiency.Thus,we found no statistically significant difference in thermal stress responses between leading and trailing populations.Nonetheless,C.officinalis showed a trend towards higher stress responses in southern than northern populations.Because responses rest on a variety of local population traits,they are difficult to predict based solely on thermal pressures.

Optimizing Biodiesel Production from Karanja and Algae Oil with Nano Catalyst:RSMand ANN Approach

This study delves into biodiesel synthesis from non-edible oils and algae oil sources using Response Surface Methodology(RSM)and an Artificial Neural Network(ANN)model to optimize biodiesel yield.Blend of C.vulgaris and Karanja oils is utilized,aiming to reduce free fatty acid content to 1%through single-step transesterification.Optimization reveals peak biodiesel yield conditions:1%catalyst quantity,91.47 min reaction time,56.86℃reaction temperature,and 8.46:1 methanol to oil molar ratio.The ANN model outperforms RSM in yield prediction accuracy.Environmental impact assessment yields an E-factor of 0.0251 at maximum yield,indicating responsible production with minimal waste.Economic analysis reveals significant cost savings:30%-50%reduction in raw material costs by using non-edible oils,10%-15%increase in production efficiency,20%reduction in catalyst costs,and 15%-20%savings in energy consumption.The optimized process reduces waste disposal costs by 10%-15%,enhancing overall economic viability.Overall,the widespread adoption of biodiesel offers economic,environmental,and social benefits to a diverse range of stakeholders,including farmers,producers,consumers,governments,environmental organizations,and the transportation industry.Collaboration among these stakeholders is essential for realizing the full potential of biodiesel as a sustainable energy solution.

Antarctic red algae in dye-sensitized photoelectrochemical cells for water splitting

Phycoerythrin extracted from Antarctic red seaweeds shows promising characteristics to be applied as an anode sensitizer in water-splitting photoelectrochemical cells.Under light irradiation and using an LED lamp,the red-colored protein shows an interesting ability to profit the incident light,as confirmed by the presence of oxygen bubbles next to the electrode surface without applying any external potential.Our results showed that the addition of iodide is helpful to allow the regeneration of the dye;nevertheless,oxygen evolution is not favored.Thermodynamics analysis of the involved semi-reactions is also helpful to understand the observed results.The exploration of Antarctic resources offers then an alternative for the development of green energies,with a particular focus on their use as sensitizers to profit from the sunlight in water-splitting as well as in photovoltaic devices.

Microscopic analysis on eukaryotic algae and cyanobacteria in nine seasonal lakes and ponds in Vestfjella,Dronning Maud Land,Antarctica

Antarctic continental lakes and ponds are among the most impoverished aquatic environments on earth but many of them support flourishing populations of cyanobacteria,eukaryotic algae,protozoans,and some multicellular animals.In this study,we present results of a microscopic analysis of cyanobacteria and eukaryotic algae from nine diverse types of Antarctic continental water bodies during one austral summer.The results supplement and enlarge our previous studies on the limnological characteristics of the epiglacial and supraglacial lakes and ponds in Dronning Maud Land,an area that has received little attention from limnologists.The taxon with highest frequency among the samples(n=79)was Mesotaenium cf.berggrenii,a eukaryotic Zygnematophyceae,which occurred in 82%of the samples with a maximum cell density of 68 cells·mL^(-1).The taxa with second and third highest frequency were the prokaryotes Gloeocapsopsis(60%)and Leptolyngbya(41%),followed by Chlamydomonas(34%)and Cyanothece(29%).The number of taxa varied between 7-21 among the lakes and ponds,being highest in a supraglacial lake,and lowest in an epiglacial lake.The results did not reveal any obvious correlation between the abundance of any taxa and the water chemistry,but water bodies with inorganic sediments had higher cell densities and biomasses than those without sediment.This suggests the importance of sediment in supporting biological diversity in these ultraoligotrophic lakes and ponds.

Interaction between Biochar and Algae on Problem Soil

An in-vitro experiment was conducted to assess the interaction between biochar and algae on a problem soil. Experiments were performed with and without algae to observe the effectiveness of algae for overcoming the challenges posed by problem soils. At the end of incubation periods, the adsorption and desorption of phosphorus (P) on a problem soil vis-á-vis algal inoculation were determined. Our results showed that different types of biochars adsorbed different amounts of P suggesting that the source of biochar played a crucial role in determining its behavior towards P. Tannery waste biochar significantly adsorbed 147% and 35% more P compared to that of the chicken litter and orange peel biochars respectively. Significant reductions in adsorption were observed when the biochar was used in combination with the algae which could be due to the beneficial effects of algae leading to the amelioration of the problem soil. Adsorption was reduced to 34%, 24% and 20% for the orange peel biochar + algae, chicken litter biochar + algae and tannery waste biochar + algae, respectively compared to the corresponding biochars present as a single solid. Phosphorus (P) desorption was also reduced significantly in presence of algal inoculation. Overall our findings suggest that the application of algae along with biochar in the problem soil could reduce the adsorption of P which would influence the availability of P.

Dynamic Analysis of an Algae-Bacteria Ecological Model

In the paper, under the framework of exploring the interaction between algae and bacteria, an algae-bacteria ecological model was established to analyze the interaction mechanism and growth coexistence mode between algicidal bacteria and algae. Firstly, mathematical work mainly provided some threshold conditions to ensure the occurrence of transcritical bifurcation and saddle-node bifurcation, which could provide certain theoretical support for selecting key ecological environmental factors and numerical simulations. Secondly, the numerical simulation work dynamically displayed the evolution process of the bifurcation dynamic behavior of the model (2.1) and the growth coexistence mode of algae and algicidal bacteria. Finally, it was worth summarizing that intrinsic growth rate and combined capture effort of algae population had a strong influence on the dynamic behavior of the model (2.1). Furthermore, it must also be noted that transcritical bifurcation and saddle-node bifurcation were the inherent driving forces behind the formation of steady-state growth coexistence mode between algicidal bacteria and algae. In summary, it was hoped that the results of this study would contribute to accelerating the study of the interaction mechanism between algicidal bacteria and algae.

Ultrasonic-Assisted Extraction of Fucoxanthin from Marine Macroalga Padina australis:Optimization,Bioactivity,and Structural Characterization

Macroalgae serve as a potential feedstock for fucoxanthin extraction.Fucoxanthin,a bioactive pigment found in the chloroplasts of marine algae,exhibits significant pharmacological properties.As a member of the carotenoid family,fucoxanthin plays a crucial role in both the food and pharmaceutical industries.This research explores the effects of ultrasonics on the extraction of fucoxanthin from the marine macroalga Padina australis.In addition,various extraction techniques and the influence of solvents on the efficient separation of fucoxanthin from algae have been studied and compared.Using methanol,chloroform,and a combination of methanol and chloroform(1:1,v/v),conventional fucoxanthin extraction from Padina australis yielded 8.12 mg of fucoxanthin per gram of biomass.However,the ultrasonic-assisted extraction resulted in a significantly higher yield of 16.9 mg of fucoxanthin per gram of biomass,demonstrating that the use of ultrasonics enhances the extraction rate compared to conventional methods.Therefore,the efficient separation of fucoxanthin from Padina australis is highly dependent on ultrasonic-assisted extraction.The process conditions for the extraction were optimized to maximize the yield of fucoxanthin from seaweeds.The following parameters were selected for optimization studies:moisture content,particle size,mixing speed,extraction temperature,extraction duration,and solid-to-solvent ratio.The extracted fucoxanthin exhibited various biological activities,including antimicrobial and antioxidant properties,and its structure was elucidated through FTIR and NMR spectroscopy.Additionally,thin-layer chromatography of the crude algae extracts confirmed the presence of fucoxanthin in the marine algae.Given these findings,the optimized extraction process holds the potential for scaling up to large-scale fucoxanthin production.Fucoxanthin,as a potent pharmacological agent,offers promising applications in the treatment of various ailments.

Analysis on the Eutrophication and Algae Blooms of Hongfeng Lake Reservoir in Guizhou

[Objective] The research aimed to know the ecological environment pollution characteristics of Hongfeng Lake water area and the evolution rule,which provided the theory basis for improving the water quality condition.[Method] Based on the investigation and research of indoor and outdoor,the water quality,aquatic ecosystem,pollution characteristic of sediment and occurrence law of algae blooms in Hongfeng Lake were comprehensively analyzed by combining with the relevant literatures.[Result] Hongfeng Lake was in moderate-heavy eutrophication situation,and the water quality was V-bad V class.The sediment accumulated a lot of nutrient salt,which was the important pollution source of eutrophication in Hongfeng Lake Reservoir.The aquatic ecosystem degraded,and it was easy to form the algae blooms.[Conclusion] The pollution treatment of Hongfeng Lake was extremely urgent.

Study on the Spatial and Temporal Distribution of Blue Algae in Lake Dianshan in Summer

To understand the spatial and temporal variation characteristics of blue algae in summer in Lake Dianshan,the phytoplankton in Lake Dianshan from June to September in 2009 was surveyed. It found 11 genera and 28 species blue algae in total. Microcystis,Oscillatoria and Chroococcus were the main composition communities of blue algae in Lake Dianshan in summer. In the survey period,the average density of blue algae in Lake Dianshan was 16.48×106 cells/L which changed during 1.01×106-59.76×106 cells/L. The characteristics were:September > July > August > June. The mass propagation and aggregation of Microcystis in September caused that the water blooms phenomenon in the partial water areas was serious. In the space,the average density of blue algae in the west and southwest parts of Lake Dianshan was bigger than in the east and southeast. When the nutritive matter was sufficient,the temperature was the main factor which affected the generation and disappearance of blue algae water blooms. The wind direction was also an important factor which affected the distribution of blue algae.

Characteristics and Comparative Study of Chlorophyll-protein Complexes from Siphonous Green Algae

By mild PAGE method, 11, 11, 7 and 9 chlorophyll_protein complexes were isolated from two species of siphonous green algae (Codium fragile (Sur.) Hariot and Bryopsis corticulans Setch.), green alga (Ulothrix flacca (Dillw.) Thur.), and spinach (Spinacia oleracea Mill.), respectively. Apparent molecular weights, Chl a/b ratios, distribution of chlorophyll, absorption spectra, low temperature fluorescence spectra of these complexes were determined, and compared with one another. PSⅠ complexes of two siphonous green algae are larger in apparent molecular weight because of the attachment of relative highly aggregated LHCⅠ. Four isolated light_harvesting complexes of PSⅡ are all siphonaxanthin_Chl a/b_protein complexes, and they are not monomers and oligomers like those in higher plants. Especially, the absence of 730 nm fluorescence in PSⅠ complexes indicates a distinct structure and energy transfer pattern.

Primary Succession of Algal Community Structure in Desert Soil

The microbiotic crust study is among new focuses in investigating on the desertification control. Based on determination of algal crusts with different successive ages (4-, 8-, 17-, 34-, 42-year-old) and unconsolidated sand in the desert area, species composition and clustering analyses were carried out in this study. Results on successional orientation revealed that (1) the abundance of Cyanophyta, specially of Scytonema javanicum gradually decreased; (2) the abundance of Chlorophyta, Bacillariophyta and a species of Cyanophyta, Phormidium tenue increased; (3) the biodiversity increased gradually with the community succession; and (4) biomass of microalgae increased at the early stage, but decreased at the later stage due to the abundance of lichens and mosses. But, the speed of natural succession was so slow that the community-building species was still the first dominant species after 42 years, except that its dominant degree decreased just slightly. However, successive speed and trend were affected by water, vegetation coverage, terrain, time and soil physico-chemical properties as well, especially Mn content in the soil appeared to have a threshold effect.

Indication Function of Aquatic Algae for Environment

In order to better monitor N and P pollutants, heavy metals, pesticides and other organic pollutants in water areas, we researched sensitivity and tolerance of aquatic algae on water environment and effects of the pollutants on algae population, analyzing toxin and enrichment of pollutants on algae. The results indicated that aquatic alga is a better indicator for some pollutants in water, for which water contamination can be surveyed and analyzed rapidly.

Biological Characteristics and Pathogenicities of Shewanella algae and Shewanella abalone from Babylonia

[Objective] The biological characteristics and pathogenicities of Shewanella algae and Shewanella abalone from Babylonia were studied in this paper. [Method]The hemolytic bacteria were isolated from the hepatopancreas of Babylonia suffered from proboscis edema with blood agar plate. The dominant bacterial community in the ill Babylonia was identified by 16 S r DNA sequence analysis, and the bacterial cultural and biochemical characteristics and pathogenicities were studied. [Result]The Shewanella bacteria, including Shewanella algae and Shewanella abalone, are the dominant bacterial community in Babylonia suffered from proboscis edema.The colony characteristics of Shewanella algae in nutrient agar medium, TCBS agar medium and CHROMagar vibrio colored medium were similar to those of Shewanella abalone. Shewanella algae possessed β-hemolysis and Shewanella abalone possessed α-hemolysis in the blood agar plate. The biochemical reaction of Shewanella algae and Shewanella abalone was all of non-fermentation type. The results of artificial infection test showed that half lethal dose（LD50） of the test strains of Shewanella algae was 10-5.50/0.1 ml. The test strains of Shewanella algae have strong toxicity, and could cause mice and chickens to die of sepsis with mortality of100%. The mortality of Babylonia infected with Shewanella algae was 10%; while the survived Babylonia lost the ability of moving and intaking for a long time, but they were not suffered from proboscis edema. There was no death in mice or chicks infected with Shewanella abalone, but their livers and spleens were slightly hyperemic and swelling. There was also no death in Babylonia infected with Shewanella abalone, but their intaking and moving ability was lost for a short time.[Conclusion] Although Shewanella algae and Shewanella abalone were the dominant bacteria in Babylonia suffered from proboscis edema, they were not the main pathogenic bacteria for proboscis edema. Shewanella algae had strong pathogenicity to mice, chicks and Babylonia, while Shewanella abalone showed no marked pathogenicity to those experimental animals in this study.

A Simple Method of Isolating Algae

[Objective] The research aimed to improve the method of isolation of algae.[Method] The samples were cultured in liquid medium after pre-culture in natural medium.[Result]12 species of algae were isolated from the sample.[Conclusion] The method is useful and easy to be handled.

ALGA在岸基导弹航路规划中的应用研究

针对基本遗传算法(GA)易局部收敛的缺陷,设计了基于模式搜索的自学习算子,提出一种基于模式搜索的自学习遗传算法(ALGA)。通过仿真测试函数将ALGA与基本遗传算法、自适应遗传算法(AGA)进行比较,显示改进的ALGA提高了算法的综合搜索能力。将改进的ALGA运用到岸基导弹航路规划中,并进行仿真实验,仿真结果验证了改进算法的有效性。

(AlGa)As可见光激光器的镜面保护

本文介绍了一种可见光激光器端面镜面保护方法。用电子束蒸发在可见光激光器的两个镜面上分别镀上0.75 λ/2和λ/2厚的 Al_2O_3钝化膜,并就镀膜对激光器性能的影响进行了测试研究。经过镜面保护的可见光激光器寿命有很大改善,且由于一个端面镀上0.75 λ/2抗反射膜,使激光器的极限输出功率有一定的提高。

Analysis of the Meteorological Conditions for Outbreak of Blue-green Algae in Hongze Lake

Based on the data of 18 cases during the past 30 years from 1978 to 2007,the major meteorological conditions for outbreak of blue-green alga in Hongze Lake were analyzed.The results showed that the main meteorological conditions that affected the production and outbreak of blue-green alga were unusual high monthly average temperature,less precipitation and more sunshine hours in ten days.Through the selection of 1 or 0 factors on the values of above meteorological conditions over the years,if the conditions were accorded with the outbreak of blue-green alga,the factor was signed as 1,or it would be signed as 0;if there was outbreak of blue-green alga within ten days,it was signed as 1,or it would be signed as 0;crossing interrelated and integrated prediction method was adopted to establish the prediction equation for outbreak of blue-green alga,the historical fitting rate was 87.5%,and the predicting accuracy rate in 2008-2009 was 87.5%.In addition to meteorological conditions,outbreak of blue-green alga was also influenced by industrial pollutions,etc.,which should be considered in the forecasting procedures.

一种新型水体在线毒性监测系统——bbe Algae Toximeter的构造、功能及调试效果

以bbe藻毒性仪为例介绍了一种新型水体在线毒性监测系统,包括其构造、功能和调试效果等,该仪器反应间隔时间短,30～60min就有比较明显反应,能监测到较低浓度Cu2+1和Cd2+离子,适用于在线监测。

Preliminary Study on Algae-lysing Active Substances of Algae-lysing Bacteria

Algae-lysing bacteria A1 has good control effect on the moss through its extracellular secretion. In order to further study its control mechanism, the sin- gle-factor tests of temperature and pH value, the activated carbon adsorption test, the organic solvent extraction test and the crude extract of active substance test were carried out to explore the characteristics of active substances. The results showed that the algae-lysing active ingredient of A1 strain had strong thermal stabili- ty, which still had good algae-lysing effect after being treated at 121 ℃ ; when the pH values of fermentation liquid were adjusted to 2.0 and 4.0 respectively, the active substances lost their activities, but their control ability against moss would be enhanced under the alkaline conditions ; the active substances could not be ad- sorbed by activated carbon; the algae-lysing active substances showed strong hydrophilie ability when they were extracted by ethyl acetate, petroleum ether and chloroform. Therefore, it could be speculated that the active substances belonged to carbohydrates. The crude extract results of algae-lysing active substances showed that the active substances secreted by A1 strain were composed by a variety of algae-lysing active substances.

Toxicity Effect of Hg^(2+) and Cr(VI) on Alga Growth in Eutrophic Water

[ Objective] The toxicity effect of Hg^2＋ and Cr（Ⅵ） on alga growth in eutrophic water was studied to provide reference for biomonitoring and bioremediation of eutrophic water. [ Method ] The mother liquid of alga, which was separated from the eutrophic water, were put into the solutions of Hg^2＋ and Cr（Ⅵ） with different concentrations and their mixture solution, respectively. And the toxicity effect of Hg^2＋ and Cr（Ⅵ） on the growth and propagation of alga in eutrophic water was observed. [ Result] The alga in eutrophic water performed rather sensitive to Cr（Ⅵ） and when its concentration was over 1 mg/L, threre was obvious effect on alga growth. The alga was not very sensitive to Hg^2＋ when its concentration was lower, but its toxicity became stronger and stronger when its concentration increased to some extent and the toxicity effect of Cr（Ⅵ） on alga growth was just on the contrary. When the ion concentration was lower than 10 mg/L, the toxicity of Hg^2＋ on alga was lower than that of Cr（Ⅵ）. When the concentration was over 10 mg/L, the toxicity of Hg^2＋ exceeded that of Cr（Ⅵ）. The toxicity of ion mixture solution of Hg^2＋ and Cr（Ⅵ） had synergism inhibition on alga, which could be performed only when the concentration was over 4 mg/L. [ Conclusion] The toxicity of heavy metal on alga not only related to the alga cell, but also related to the concentration of heavy metal ion.