Factors inducing morphological transition in harmful algal bloom-forming species Phaeocystis globosa with emphasis on predator chemical cue

The microalga Phaeocystis globosa is recognized as a harmful alga and also one of the few keystone phytoplankton genera that shape the structure and function of marine ecosystems.P.globosa possess a complex polymorphic life cycle,exhibiting phase alternation between free-living cells of approximately 3-6μm in diameter and gelatinous colonies(palmelloid stage)reaching several millimeters.The knowledge on the factors that induced the morphological transition of P.globosa in the last two decades was reviewed.Emphasis is given to infochemicals,an additional biological factor induced by predator,with the attempt to reveal a relevant mechanism of induced morphological defense.

Distribution Characteristics of Sulfur and the Main Harmful Trace Elements in China's Coal

To promote the rational development and use of clean coal resources in China, data on the regional and age distribution of sulfur, arsenic and other harmful elements in Chinese coal was broadly collected, tested for content, and analyzed. Coal in northwestern China is characterized by low to extremely low levels of sulfur; the coal of the Taiyuan Formation in northern China mainly has high-sulfur content; that of the Shanxi Formation is mainly characterized by low sulfur coal; and the Late Permian coal in southern China has overall higher sulfur content; other regions have low sulfur coal. The average content of harmful trace elements in the bulk of China＇s coal is similar to the corresponding content in the coal of the North America and the rest of the world, whereas the content of various elements （Hg, Sb and Se） is different in magnitude to the corresponding percentage in the crust. The average content of the elements Cr, Se, Co, Be, U, Br in Late Permian coal in S China ranks first in the country whereas the average content of Hg and CI in the coals of Late Carboniferous to Early Permian age in N China are the highest. The average content of Mn in Early and Middle Jurassic coal is higher in NW China. The high content of harmful elements in some coal should cause particular concern both in the development and utilization of coal.

Spatio-temporal variations of harmful algal blooms along the coast of Guangdong,Southern China during 1980–2016

Harmful algal blooms (HABs) have become a recurring problem, posing severe impacts on marine ecosystems, fisheries, mariculture industry, and even public health. In this study, the geographic information system (GIS) was utilized to determine spatial and temporal characteristics of HAB events in the coastal waters of Guangdong from 1980–2016. We analyzed distribution patterns and characteristics of HABs by dividing the coast of Guangdong into well-known bays, estuary and coastal waters. Results showed that there were a total of 337 HABs recorded in Guangdong coastal waters. Spatial and temporal distributions varied among diff erent regions. Most HABs occurred in the Mirs Bay, followed by the west coast of Daya Bay, while a few occurred in the west and east coasts of Guangdong but with an increasing trend in the past two decades. HABs occurred mostly in warmer months of March to May in the western coast of Guangdong, March and April in Mirs Bay, April in Zhujiang (Pearl) River estuary, November in eastern coast of Guangdong. For Daya Bay, most HABs were reported between March and September. The most frequently occurring HABs species were Noctiluca scintillans , Phaeocystis globosa , Skeletonema costatum and Scrippsiella trochoidea , occurring mostly in Mirs Bay, western Guangdong coast area, eastern Guangdong coast area and Zhujiang River estuary and Daya Bay, respectively. Ichthyotoxic blooms were more common than toxic blooms, and Heterosigma akashiwo , Chattonella marina , Karenia mikimotoi and P haeocystis globosa were the most common ichthyotoxic species. Our results provide baseline information useful for policy making and management of HABs in the region.

Effects of irradiance on pigment signatures of harmful algae during growth process

Three harmful algal bloom （HAB） species, Phaeocystis globosa, Thalassiosira rotula, and Prorocentrum donghaiense were isolated from the coast of China and cultured in batches at three light intensities （40, 70 and 150 μmol photons · m -2 · s -1 ）. The variation patterns of cell numbers and growth rates with light intensity during growth process were different among species. In P. globosa and T. rotula, maximum growth rates were found at 150 μmol photons · m -2 · s -1 and ranged from 0.60 divisions per day in T. rotula, to 1.17 divisions per day in P. globosa. The highest growth rate of P. donghaiense, however, was found at 70 μmol photons · m -2 · s -1 （0.36 divisions per day）. In general, all the three HAB species showed adaptation to increasing light intensity by decreasing cellular concentrations of chlorophyll a （Chl a）, but the variation patterns during the growth process were species-specific. The cellular concentrations of Chl a in P. donghaiense and T. rotula increased gradually with incubation time, but the opposite trend was found in P. globosa. Most of the pigment ratios and pigment indices of these three species were nearly constant during the growth process and showed small changes at different light intensities illustrating the applicability of chemotaxonomy during the initial and developing stages of HAB events, which is very important to study the ecological issues related to HAB species. Ratios of photoprotective carotenoids, such as diadinoxanthin, diatoxanthin and β, β-carotene to total chlorophylls a （Tchl a） showed the trend of increasing with the increase of light intensity during growth process. The species-specific and pigment-specific variations in pigment ratios/indices at different light intensities during growth process probably reflected the differences in the pigment composition as well as the adaption capabilities of different species to the changes of physical conditions.

Characteristics of Large-Scale Harmful Algal Blooms (HABs) in the Yangtze River Estuary and the Adjacent East China Sea (ECS) from 2000 to 2010

Harmful algal blooms (HABs) are a serious worldwide issue which has posed great risks on marine ecosystems and public health by directly releasing toxins or indirectly leading to anoxia in marine environment. In recent years HABs have caused huge economic losses in China, particularly in the Yangtze Estuary and the adjacent East China Sea (ECS). The present study investigated the spatial-temporal and species characteristics of large-scale HABs in this area using geographic information system (GIS) Kernel Density Estimation (KDE) spatial analysis, statistical methods and satellite image interpretation. Results revealed that the Yangtze Estuary, Zhoushan island, Xiangshan bay and Jiushan island are the regions with highest frequency of large-scale HABs. HABs in the ECS reached a peak in terms of total number and area in 2003 to 2005 and occupied a high percentage (around 70% in area and 60% in occurrence) in the four Chinese coastal waters. The number of large-scale HABs (> 1000 km2) in the Yangtze Estuary and the adjacent ECS declined after 2005 while that of HABs (> 100 km2) declined after 2008. Large-scale HABs occurrences concentrated in summer (May to July), and the averaged duration increased continually from the shortest time (1.3 days) in 2001 to the longest (10.9 days) in 2010 for each HAB. 17 causative species were found with Prorocentrum dentutam as the most frequent dominant species, followed by Skeletonema costatum, Karenia mikimotoi, and Chaetoceros curvisetus. Water discoloration observed in MODIS satellite true color images was well consistent with the corresponding HABs reported by State Oceanic Administration of China (SOA). Multiple factors involving eutrophication, physical dynamics, topography and deposition conditions contributed to the formation of frequent HABs in the ECS. Three strategies including establishing a synthesized system, improving the previous database and investigating multiple contributors were proposed for future HABs monitoring and management.

Potentially harmful metals,and health risk evaluation in groundwater of Mardan,Pakistan:Application of geostatistical approach and geographic information system

This study investigates the values of pH,total dissolved solids(TDS),elevation,oxidative reduction potential(ORP),temperature,and depth,while the concentrations of Br,and potentially harmful metals(PHMs)such as Cr,Ni,Cd,Mn,Cu,Pb,Co,Zn,and Fe in the groundwater samples.Moreover,geographic information system(GIS),XLSTAT,and IBM SPSS Statistics 20 software were used for spatial distribution modeling,principal component analysis(PCA),cluster analysis(CA),and Quantile-Quantile(Q-Q)plotting to determine groundwater pollution sources,similarity index,and normal distribution reference line for the selected parameters.The mean values of pH,TDS,elevation,ORP,temperature,depth,and Br were 7.2,322 mg/L,364 m,188 mV,29.6℃,70 m,0.20 mg/L,and PHMs like Cr,Ni,Cd,Mn,Cu,Pb,Co,Zn,and Fe were 0.38,0.26,0.08,0.27,0.36,0.22,0.04,0.43 and 0.86 mg/L,respectively.PHMs including Cr(89%),Cd(43%),Mn(23%),Pb(79%),Co(20%),and Fe(91%)exceeded the guideline values set by the world health organization(WHO).The significant R^(2)values of PCA for selected parameters were also determined(0.62,0.67,0.78,0.73,0.60,0.87,-0.50,0.69,0.70,0.74,-0.50,0.70,0.67,0.79,0.59,and-0.55,respectively).PCA revealed three geochemical processes such as geogenic,anthropogenic,and reducing conditions.The mineral phases of Cd(OH)_(2),Fe(OH)_(3),FeOOH,Mn_(3)O_(4),Fe_(2)O_(3),MnOOH,Pb(OH)_(2),Mn(OH)_(2),MnO_(2),and Zn(OH)_(2)(-3.7,3.75,9.7,-5.8,8.9,-3.6,2.2,-4.6,-7.7,-0.9,and 0.003,respectively)showed super-saturation and under-saturation conditions.Health risk assessment(HRA)values for PHMs were also calculated and the values of hazard quotient(HQ),and hazard indices(HI)for the entire study area were increased in the following order:Cd>Ni>Cu>Pb>Mn>Zn>Cr.Relatively higher HQ and HI values of Ni,Cd,Pb,and Cu were greater than one showing unsuitability of groundwater for domestic,agriculture,and drinking purposes.The long-term ingestion of groundwater could also cause severe health concerns such as kidney,brain dysfunction,liver,stomach problems,and even cancer.

A numerical model study on multi-species harmful algal blooms coupled with background ecological fields

Based on systematized physical, chemical, and biological modules, a multi-species harmful algal bloom （HAB） model coupled with background ecological fields was established. This model schematically embod-ied that HAB causative algal species and the background ecological system, quantified as total biomass, were significantly different in terms of the chemical and biological processes during a HAB while the inter-action between the two was present. The model also included a competition and interaction mechanism between the HAB algal species or populations. The Droop equation was optimized by considering tempera-ture, salinity, and suspended material impact factors in the parameterization of algal growth rate with the nutrient threshold. Two HAB processes in the springs of 2004 and 2005 were simulated using this model. Both simulation results showed consistent trends with corresponding HAB processes observed in the East China Sea, which indicated the rationality of the model. This study made certain progress in modeling HABs, which has great application potential for HAB diagnosis, prediction, and prevention.

Sustainable Utilization of Agricultural Straw for Harmful Algal Blooms Control:A Review

The use of agricultural straw for algal bloom control has been studied for more than 30 years.In this article,we have reviewed the promising potentials of using agricultural straw as source of anti-algal agents,including the effectiveness of each major straw type so far used in this regard,and the investigated algal species.Various pre-treatment methods have also been widely reviewed.Significant progress has been made in natural product chemistry and molecular biology with regards to agricultural straw,especially in relation to the extraction of antialgal allelochemicals,degradation processes of agricultural straws and the mechanisms through which these inhibitions occur.The development of biotechnologies using agricultural straw to successfully inhibit growth of bloom forming algae has been generally accepted as environmentally friendly.The current research status and that of the future should include isolation and discovery of antialgal allelochemicals,development of models that would illustrate the sequence of physiologic events that match the species-specific inhibitor phenomenon,and products fit in the field applications.

Harmful Effects of MSG on Function of Hypothalamus-Pituitary-Target Gland System

It has been demonstrated that neonatal administration of monosodium glutamate (MSG) results in a clearly defined lesion of the arcuate nucleus (AN) of the hypothalamus.The present study shows that fat was accumulated in the abdomen of male rats treated with MSG; weights of the body, pituitary and testis were lower, 6-EP content in hypothalamus decreased while L-EnK content increased, serum LH, FSH, TSH, GH and TS levels all decreased in varying degrees while serum PRL level significantly increased. The cAMP content lowered in pituitary, but nor in testes; clear histological changes occurred in testicular tissue; Se-GSH-Px activity in both testis and adrenal gland lowered while LPO level significantly increased. Both Se-GSH-Px activity and LPO level in liver increased.These results indicate that MSG is harmful to the function of the hypothalamus-pituitarytarget system of neonatal rats

Harmful algal bloom-forming dinofl agellate Prorocentrum donghaiense inhibits the growth and photosynthesis of seaweed Sargassum fusiformis embryos

Harmful algal bloom(HAB)is an ecological disaster to local mariculture.At present,its impact on macrophytes has not been well studied.In this study,we cultivated sexually propagated embryos of S argassum fusiformis-an edible seaweed-in Prorocentrum donghaiense suspensions at different cell densities(0,0.50×10^(5),0.75×10^(5),1.00×10^(5),and 1.50×10^(5) cells/mL)for 10 days,during which growth and photosynthetic activities of the embryos were determined,and a monocultivation was set up for comparison.Results show that the relative growth rate and photosynthetic activities of the embryos co-cultivated with P.donghaiense were inhibited mostly and significantly in the cell densities of 0.75×10^(5),1.00×10^(5),and 1.50×10^(5) cells/mL,and the inhibitory effects increased in overall with increased cell densities.The maximum relative electron transport rates(rETR max)and apparent photosynthetic efficiency(a)of co-cultivated embryos were all significantly lower than monocultivation ones on the 10 th day.Furthermore,the photosynthetic activity detected by chlorophyll-a fluorescence transient(i.e.,OJIP),the electron transport among electron transfer accepters of PSII(photosystem II)and that from PSII to PSI(photosystem I)was restricted,which is probably responsible for the decreases of rETR max andain the co-cultivated embryos.In addition,parts of the photosynthetic reaction centers of PSII in the co-cultivated embryos were inactivated.Therefore,P.donghaiense bloom could restrain the development and photosynthetic activities of S.fusiformis embryos,reduce the seedlings stock,and eventually hinder the development of S.fusiformis production industry.

Tidal water exchanges can shape the phytoplankton community structure and reduce the risk of harmful cyanobacterial blooms in a semi-closed lake

For estuaries,inland lakes play a vital role in the ecological balance under the impact of tide s.The effect of tides-induced water exchange on phytoplankton community in a semi-closed lake was studied and compared with that of an adjacent closed lake in the Oujiang River mouth in Zhejiang,East China Sea,from June 29,2020 to June 14,2021.Results show that the dominant species,abundance,dominance,and diversity of the phytoplankton species between the two lakes were significantly different.In the closed lake,cyanobacteria were the dominant species during the study period.However.in the semi-closed lake,the diversification of the dominant species was greater,and some species of diatoms and green algae became dominant.The average phytoplankton abundance in the closed lake was 6 times of that in the semi-closed lake.The average dominance of cyanobacteria in the closed lake was 0.96,and those in the semi-closed lake and the Oujiang River were 0.51 and 0.22,respectively.Cyanobacterial blooms occurred throughout the study time in the closed lake but not in the semi-closed one.Furthermore,the species diversity richness of the phytoplankton in the semi-closed lake was higher than that of the closed one,and the phytoplankton community between the closed lake and semi-closed lake could be divided into distinctly different groups based on non-metic multidimensional scaling analysis(NMDS)and analysis of similarities(ANOSIM)analysis.The salinity of the water was significantly greater and the transparency significantly smaller in the semi-closed lake than those in the closed lake.Therefore,water exchange driven by local tidal movement increased salinity and decreased transparency of water,which consequently shaped the community structures of different phytoplankton and reduced the risk of a cyanobacterial bloom outbreak in the semi-closed lake.

Statistical Monitoring Method for Pesticides and Harmful Substances

A statistical monitoring method has been developedfor accurate, safety surveillance methods of γ-BHC resideueor harmful substances in foods or feeds. It is very importantfor safety monitoring and arbitrament inspections. This paperintroduces a calculation formula by a six-point calibrationmethod and an example for detection of Y-BHC in corn.The method can guarantee the accuracy of the results,and it does very substantially reduce the probability of an er-ror by one-point calibration.

STABILITY AND BIFURCATION BEHAVIORS ANALYSIS IN A NONLINEAR HARMFUL ALGAL DYNAMICAL MODEL

A food chain made up of two typical algae and a zooplankton was considered. Based on ecological eutrophication, interaction of the algal and the prey of the zooplankton, a nutrient nonlinear dynamic system was constructed. Using the methods of the modern nonlinear dynamics, the bifurcation behaviors and stability of the model equations by changing the control parameter r were discussed. The value of r for bifurcation point was calculated, and the stability of the limit cycle was also discussed. The result shows that through quasi-periodicity bifurcation the system is lost in chaos.

Analysis of diffusion behavior of harmful emissions from trackless rubber-wheel diesel vehicles in underground coal mines

To define the diffusion behavior of harmful exhaust substances from diesel vehicles and support safety risk assessments of underground coal mines,we performed a multi-species coupling calculation of the emission and diffusion of harmful substances from a trackless rubber-wheel diesel vehicle.A computational fluid dynamics(CFD)model of the diffusion of harmful emissions was hence established and verified.From the perspective of risk analysis,the diffusion behavior and distribution of hazardous substances emitted by the diesel vehicle were studied under 4 different conditions;moreover,we identified areas characterized by hazardous levels of emissions.When the vehicle idled upwind in the roadway,high-risk areas formed behind and to the right of the vehicle:particularly high concentrations of pollutants were measured near the rear floor of the vehicle and within 5 m behind the vehicle.When the vehicle idled downwind,high-risk areas formed in front of it:particularly high concentrations of pollutants were measured near the floor and within 5 m from the front of the vehicle.In the above cases,the driver would not breathe highly polluted air and would be relatively safe.When the vehicle idled into the chamber,however,high-risk areas formed on both sides of the vehicle and near the upper roof.Forward entry of the vehicle caused a greater increase in the concentration of pollutants in the chamber and in the driver’s breathing zone compared with reverse entry.

Relationship between toxic and harmful microalgae and environmental factors in typical mariculture areas of East China Sea

Toxic and harmful algal blooms are usually more frequent in mariculture areas due to the abundant trophic conditions.To investigate the relationship between toxic and harmful microalgae and environmental factors,we set up 12 stations near three mariculture regions(Gouqi Island,Sandu Bay,and Dongshan Bay)in the East China Sea.We collected samples from all four seasons starting from May 2020 to March 2021.We identifi ed 199 species belonging to 70 genera,of which 38 species were toxic and harmful,including 24 species of Dinophyceae,13 species of Bacillariophyceae,and 1 species of Raphidophyceae.The species composition of toxic and harmful microalgae showed a predominance of diatoms in the summer(August),and dinofl agellates in the spring(May),autumn(November),and winter(March).The cell densities of toxic and harmful microalgae were higher in summer(with an average value of 15.34×10^(3) cells/L)than in other seasons,3.53×10^(3) cells/L in spring,1.82×10^(3) cells/L in winter,and 1.0×10^(3) cells/L in autumn.Pseudo-nitzschia pungens,Prorocentrum minimum,Paralia sulcata,and Prorocentrum micans were the dominant species and were available at all 12 stations in the three mariculture areas.We selected 10 toxic and harmful microalgal species with frequency>6 at the survey stations for the redundancy analysis(RDA),and the results show that NO^(-)_(3),water temperature(WT),pH,DO,and NO^(-)_(2) were the main factors on distribution of toxic and harmful microalgae.We concluded that the rich nutrient conditions in the East China Sea mariculture areas increased the potential for the risk of toxic and harmful microalgal bloom outbreaks.

Laboratory simulation of dissolved oxygen reduction and ammonia nitrogen generation in the decay stage of harmful algae bloom

To evaluate how the decay of bloom-forming algae affect the coastal dissolved oxygen,a laboratory simulation was conducted in terms of three typical harmful algae,Alexandrium catenella,Prorocentrum donghaiense,and Skeletonema costatum.Algae of same biomass(55μg/mL)were conducted in lightproof columns,and the cell density,dissolved oxygen(DO),and ammonia nitrogen of different layers were monitored at certain time series.Results show that the decomposition of algae significantly decreased the DO,and increased the ammonia nitrogen in all layers;and significant deference between different species was observed.The A.catenella treatment showed the lowest DO(average concentration of 3.4 mg/L)and the highest ammonia nitrogen(average concentration of 0.98 mg/L)at the end of test,followed by P.donghaiense;and the S.costatum showed relatively high DO and low ammonia nitrogen due to slow decay rate.Results indicate that decomposition of harmful bloom algae,especially dinoflagellate,would cause significantly DO depletion and toxic ammonia nitrogen increase,which will detrimentally affect both pelagic and benthic ecosystem.

Information standardization for typical toxic and harmful algae in China's coastal waters——a case study of Karenia mikimotoi

To assist the researches of toxic and harmful algae and provide government workers with judgment basis for decision-making related events,we established a biological information management system for toxic and harmful algae in China’s of fshore to assist relevant research.In this study,Karenia mikimotoi was studied as a typical toxic and harmful algae species,and the basic biological information and biogeographic distribution information of K.mikimotoi were systematically studied and collected.In the part of basic biological information,the name,toxin,and molecular characteristic sequence of K.mikimotoi were sorted out by literature searching and website browsing.Through experimental means,the relevant information of morphological identifi cation,pigment composition,and lipid composition were obtained.In the part of biogeographic distribution information,this study sorted out the information of K.mikimotoi,analyzed the characteristics of its occurrence,and completed the standardized construction of biogeographic distribution information.Through the collation of basic biological information and biogeographic distribution information of K.mikimotoi,the standardization of related information was completed,which provided template and method reference for information collection of other toxic and harmful algae species,which was benefi cial to the database analysis and design.

Oxidative effects of the harmful algal blooms on primary organisms of the food web

Degraded water quality from nutrient pollution,physical,biological,and other chemical factors contributes to the development and persistence of many harmful algal blooms(HAB s).The complex dynamics of the HAB s is a challenge to marine ecosystems for the toxic effects reported.The consequences include fish,bird,and mammal mortality,respiratory or digestive tract problems,memory loss,seizures,lesions and skin irritation in many organisms.This review is intended to briefly summarize the recent reported information on harmful marine toxin deleterious effects over the primary organisms of the food web,namely algae,zooplankton and invertebrates.Special focus is made on oxidative stress status of cells and tissues.Even though in situ field research is less controlled than laboratory studies,in which the organisms are directly exposed to the toxins under consideration,both types of approaches are required to fully understand such a complex scenario.On top of that,the contribution of the increasing water temperatures in the sea,as a consequence of the global climate change,will be addressed as a topic for further studies,to evaluate the effect on regulating algal growth,species composition,trophic structure,metabolic stress and function of aquatic ecosystems.

Formation and harmfulness of high fluoride-bearing ground-water

According to the distribution of high fluoride\|bearing groundwater in Liaoning Province, China, the cause of formation and hydrogeochemical characteristics as well as its relationship with human health and illness rate were discussed. Strategies to prevent and control fluoride pollution have also been outlined.

Prevention of Harmful Algal Blooms by Control of Growth Parameters

Harmful Algal Blooms (HAB) were investigated to prevent the outbreak of HAB in both freshwater and seawater. Parameters inducing HAB were volcanic eruption, sunlight, aeolian dust, environmental factors (current, pH, dissolved oxygen, food web, turbulence, growth phase), enzyme, iron, nutrients (carbon, nitrogen, phosphorus, sulfur, silicon, minerals) while the critical growth parameter for the outbreak of HAB was iron (Fe). HAB development was halted in freshwater and seawater due to the sulfur compounds (H2S, sulfates) inducing the deficiency of the dissolved Fe in the water. The atomic ratio of N/P is commonly known to be 16/1 in freshwater and 176/1 in seawater for HAB. Therefore, nitrogen can be a relatively limiting factor in seawater while phosphorus in freshwater. HAB could be prevented by control of growth parameters such as pH, temperature, sunlight, turbulence, nitrogen, phosphorus, iron, and sulfur compounds prior to reaching the early exponential phase of algal growth.