Different Concentrations Of Nitrate Research Articles

Passive phosphorus capture in biofiltration context: nitrate impact on the performance

ABSTRACT Research on the development of a passive phosphorus entrapment process characterized by biofilters with active wood-based media impregnated with iron hydroxide has been conducted. Phosphorus removal was done by sorption which includes adsorption, exchange of ions and precipitation. Experiments were performed in order to investigate the effect of nitrate, generally present at the end of secondary treatment, on the phosphorus removal performance. Columns tests were performed with anaerobic activated wood-based media and immersion over a period of 150 days. Columns were fed for 32 days with a synthetic solution of 5 mg P L−1. Different concentrations of nitrate (5, 10 and 25 mg N-NO3 L−1) were then applied on three columns (C2, C3 and C4), column C1 serving as a control. Results showed total phosphorus (TP) removal efficiencies of 96.9%, 81.7%, 70.6% and 75.7%, respectively, for C1, C2, C3 and C4. Addition of nitrate increases the oxidoreduction potential (ORP). This results in an inhibition of the reductive dissolution, characterized by a decrease in the release of ferrous ions. Simultaneous denitrification occurs within the columns. It is both biological and chemical through the oxidation of ferrous ions by NO2, produced during biological denitrification. Furthermore, bacterial identification tests have highlighted the presence of iron-related bacteria (Pseudomonas, Thiobacillus, Enteric bacteria, e.g. E. coli), slym forming bacteria, sulphate reducing bacteria and denitrifying microorganisms such as Pseudomonas and E. bacteria in biofilters.

Production of aminated peat from branched polyethylenimine and glycidyltrimethylammonium chloride for sulphate removal from mining water

A novel bio-based anion exchanger was developed to remove sulphate from synthetic solutions and mine water. Different modification parameters such as chemical dosage and reaction time were tested when using a unique combination of branched polyethylenimine (PEI) and glycidyltrimethylammonium chloride (GTMAC) to produce an aminated biosorbent (termed PG-Peat). The novel and environment-friendly modification method was shown by FTIR and XPS analyses to be able to introduce quaternary ammonium and N-H groups into PG-Peat. The optimal modification conditions (PEI: 0.26 mmol/g, GTMAC: 0.0447 mol/g, reaction time: 18 h) resulted in the maximum sulphate uptake capacity (189.5 ± 2.7 mg/g) with a partition coefficient value of 0.02 mg/g/μM under acidic conditions. At low pH, amine groups on the peat surface became cationized, thereby resulting in a higher sulphate removal capacity. Batch sorption tests using PG-Peat exhibited rapid sulphate sorption after only five minutes of contact. The sulphate uptake by PG-Peat was unaffected by the presence of varying chloride concentrations, while slightly lower uptake capacity was observed when different concentrations of nitrate were present. The biosorbent showed high recyclability, which was revealed in regeneration studies. Tests were performed involving real mine water, where PG-Peat showed its potential to be a highly efficient biosorbent for sulphate removal at low pH values, indicating its suitability for treating acidic mine waters.

Salt stress effects on enzymes activities involved in carbon metabolism and nitrogen availability of two Tunisian durum wheat varieties

Two varieties of durum wheat (Om Rabiaa and Karim), were analyzed and evaluated in the presence of increasing doses of NaCl (0, 100, 200 and 300 mM) in which we added different concentrations of nitrate (0.1, 3, 10 mM). The data obtained showed that presence of NaCl in the culture medium induces the increase of the salt accumulation levels (Na+, Cl−) and reduces the levels of K+ and NO3− in the cultivar Om Rabiaa. In Karim variety, ions that have been heavily accumulated following exposure to NaCl are Na+ and K+ while low levels of NO3− and Cl− have been detected. Those findings highlight the difference in the salinity tolerance of durum wheat cultivars also depending on nitrogen (N) availability, Karim cultivar being less sensitive to NaCl treatment than Om Rabiaa. These data also suggested a relationship between salt tolerance capacity and enhancement of nitrogen and carbon metabolisms enzyme activity.

Non-lethal nitrate supplementation enhances photosystem II efficiency in mixotrophic microalgae towards the synthesis of proteins and lipids

The current study is aimed at understanding the effect of two different concentrations of nitrate (NaNO3) i.e., 2.94 mM (1X) and 8.82 mM (3X) on the productivity of Scenedesmus sp. in terms photosynthetic efficiency, growth, biomass and protein/lipid synthesis. The experiments were conducted by growing the microalgae in mixotrophic mode with a fixed dissolved organic carbon (110 mM). Chlorophyll a fluorescence fast kinetics parameter such as FV/FM, FM/FO, Pi_Abs, TRo/RC and ABS/RC depicted an improved PSII efficiency in 3X conditions. Higher nitrate concentration in BBM medium favored better assimilation of chlorophyll pigments, carbohydrates (160 mg/g), proteins (524 mg/g) and total lipids along with higher biomass (11.4 g/L). The microalgae cell growth, biomass and biochemical composition are significantly influenced by excess nitrates supplementation in the growth medium.

Binding affinity of pyridines with AmIII/CmIII elucidated by density functional theory calculations.

In recent decades, N-heterocyclic ligands have been extensively used in the separation of lanthanides/actinides, whereas the selective extraction of amercium or curium has been very challenging. Using density functional theory calculations, this study is devoted to the investigation of the binding affinity of a series of modelling pyridine ligands with AmIII and CmIII. The structure-property correlations between the amercium and curium systems and the binding affinity were obtained, and promising strategies for efficient separation of AmIII/CmIII were proposed.

Effect of nitrogen sources on fruit characteristics and seed physiological quality of Physalis angulata L.

ABSTRACT Choosing an appropriate nitrogen source is of utmost importance, since it affects the plant development and fruit and seed yield. This study aimed to evaluate the quality of Physalis angulata fruits and seeds obtained from plants grown in a hydroponic system, under different concentrations of nitrate and ammonium. The treatments consisted of four NO3-:NH4+ ratios (100:0, 75:25, 50:50 and 25:75). After full grown, the fruits were collected for biometric and chemical analyses, and seeds were removed for the germination test. The germination test was conducted in a germination chamber and the parameters evaluated were the germination rate, mean germination time, speed, germination uniformity coefficient and relative frequency. Fruits with lower weight and diameter were obtained at doses above 50 % of ammonium; however, there was an increase for ºBrix and soluble solids/titratable acidity ratio. Such dosage also reduced the rate, speed and uniformity of germination. The combined use of nitrogen sources (50:50 of NO3-:NH4+) is recommended, because it produces larger and sweeter fruits with vigorous seeds.

Physiological and Nutritional Responses of Pear Seedlings to Nitrate Concentrations.

Nitrogen (N) is an important element for plant growth, and a suitable N supply is crucial to ensure optimal yields from fruit trees. Frequently, application of N fertilizers to fruit trees is often excessive, which not only leads to environmental pollution, but also reduces the output from fruit trees through N toxicity. To evaluate the effects of different concentrations of nitrate on plant growth, root-morphological traits, and other nutritional element’s responses in pear, pear seedlings (Pyrus betulifolia Bunge) were treated with five levels of N. Both N-deficiency and an excess of N inhibited the growth and development of pear rootstocks. However, different visible symptoms were observed among treated leaves and roots. Leaf yellowing, the stimulation of root elongation, a decrease in nitrate reductase activity and chlorophyll content were observed under N-deficiency conditions. On the other hand, dark green leaves accompanied by coking, the suppression of root elongation, and a decrease in nitrate reductase activity and chlorophyll content were displayed under regimes of excess N. In addition, not only the N content, but also the content of other mineral nutrients was influenced by nitrate treatments. Taken together, these results suggested that a careful choice of N fertilizer supply is crucial to ensure normal growth and development in pear trees.

Exposure to nitrate alters the histopathology and gene expression in the liver of Bufo gargarizans tadpoles

Nitrate is a ubiquitous component in aquatic environment and the concentrations of anthropogenic nitrate-nitrogen (NO3N) can exceed 25 mg/L in surface waters and 100 mg/L in ground waters. The exceed nitrate has adverse effects on survival, development, and metamorphosis of amphibian. Liver is the hub of many biological processes, including lipid metabolism and bile salts secretion. However, there is little information about the effects of nitrate on the liver in amphibians during metamorphosis. In this study, B. gargarizans was exposed to different concentrations of nitrate from embryo to metamorphosis climax to investigate the effects of nitrate on the liver. The survival rate, metamorphosis percent, body mass, total length, and hind-limb length were measured. The histopathological changes and transcriptome responses in the liver of B. gargarizans to nitrate were examined. Results indicated exposure to 50 and 100 mg/L NO3N delayed the metamorphosis and decreased the metamorphosis percent of B. gargarizans. The body size of B. gargarizans at 10 and 50 mg/L NO3N groups were decreased while it was increased at 100 mg/L NO3N group. In addition, exposure to 100 mg/L NO3N caused severe histopathological changes, including cellular atrophy, increased intercellular areas, degraded lipid droplets, hepatic fibrosis, bile canaliculus contraction and degraded mitochondria in liver. The results of RNA-seq and qRT-PCR interpreted the molecular responses, which might be the factors to induce histopathological changes in the liver of B. gargarizans under the pressure of nitrate exposure.

Economical approach to nitrate removal via membrane capacitive deionization

Groundwater is the most widely used water resource worldwide. In addition to natural underground pollutants, it is also affected by anthropogenic pollution sources. Highly soluble nitrate can easily leak into groundwater via precipitation. Nitrate has the potential to produce nitrosamines and thus can cause blue baby syndrome as well as several types of cancer, including that of the digestive system. Moreover, nitrates lead to eutrophication in bodies of water such as rivers and lakes. Therefore, organizations such as the World Health Organization (WHO) and the US Environmental Protection Agency (EPA) have limited the maximum acceptable nitrate concentration in drinking water to 10 mg/L. These adverse effects make it necessary to remove nitrates from water. The membrane capacitive deionization (MCDI) process can successfully remove nitrate. In this study, solutions with different concentrations of nitrate were treated via MCDI at different removal efficiencies, resulting in nitrate reductions below the limit values. Thus, the MCDI process proved to be an economical treatment approach, and during the treatment phase no significant effect of nitrate concentration levels was observed on the recovery efficiency. During the MCDI treatment, the electrodes accepted the SO42− and NO3− ions approximately equally, while Cl− removal rate was lower. Groundwater obtained from the Meric district of Edirne (Turkey) containing 233 mg/L nitrate was successfully purified via the MCDI process, with a nitrate removal efficiency of 98%. The energy expenditure calculated for the nitrate removal treatment of the groundwater was 0.4 kWh/m3.

Screening of Debaryomyces hansenii Strains for Flavor Production under a Reduced Concentration of Nitrifying Preservatives Used in Meat Products.

A total of 15 Debaryomyces hansenii strains from different food origins were genetically characterized and tested on a culture medium resembling the composition of fermented sausages but different concentrations of nitrifying preservatives. Genetic typing of the D. hansenii strains revealed two levels of discrimination: isolation source or strain specific. Different abilities to proliferate on culture media containing different concentrations of nitrate and nitrite, as sole nitrogen sources and in the presence of amino acids, were observed within D. hansenii strains. Overall metabolism of amino acids and generation of aroma compounds were related to the strain origin of isolation. The best producers of branched aldehydes and ethyl ester compounds were strains isolated from pork sausages. Strains from cheese and llama sausages were good producers of ester compounds and branched alcohols, while vegetable strains produced mainly acid compounds. Nitrate and nitrite reduction affected in different ways the production of volatiles by D. hansenii.

EFFECT OF CEC OF CLAY ON THERMAL CONDUCTIVITY

The thermal conductivity of clay doped with different concentrations of nitrate of heavy metals is presented in this study. Clay sample from Omi Adio, Ibadan, Southwestern part of Nigeria was used to investigate this work. Cation exchange, which occurs naturally with soil water, was the method explored to carry out the investigation. A microprocessor-based thermal analyzer was used to determine the thermal conductivity while Atomic absorption spectrophotometer was used to determine the heavy metal concentration. 52.0 g clay sample was mixed with 70 cm3 of nitrate of Pb (II), Cd (II), Zn (II), Cr (II), Fe (II), Hg(II), Cu (II), and Ni (II) solutions at different concentrations; after which slabs of dimensions 4cm x 4cm x 1cm were made from the mixture of the clay sample with aqueous solutions of different concentrations and the thermal conductivities determined. Thermal conductivity values were plotted against concentration of nitrate of heavy metals; 400 ppm, 800 ppm, 1600 ppm, 3200 ppm and 6400 ppm. Results showed that thermal conductivity of clay increases with increase in the concentration of heavy metal adsorbed by the clay to an optimum level. The lowest thermal conductivity was found to be 0.06W/mK (for control clay) and the highest was found to be 0.38W/mK (at 6400ppm, Copper). For all the samples, thermal conductivity increases as the concentration of heavy metals increases to a certain optimum level above which cation exchange is no longer possible. From the results, it was concluded that the increase of concentration of heavy metals adsorbed by clay during cation exchange process contributes to its thermal conductivity.Keywords: Adsorption, Clay, Concentration, Thermal conductivity, Heavy metals

Maximization of cell growth and lipid production of freshwater microalga Chlorella vulgaris by enrichment technique for biodiesel production.

Chlorella vulgaris was cultivated under limitation and starvation and under controlled conditions using different concentrations of nitrate (NaNO3) and phosphate (K2HPO4 and KH2PO4) chemicals in modified Bold basal medium (BBM). The biomass and lipid production responses to different media were examined in terms of optical density, cell density, dry biomass, and lipid productivity. In the 12-day batch culture period, the highest biomass productivity obtained was 72.083mgL-1day-1 under BBM - NcontrolPlimited condition. The highest lipid content, lipid concentration, and lipid productivity obtained were 53.202%, 287.291mg/L, and 23.449mgL-1day-1 under BBM - NControlPDeprivation condition, respectively. Nitrogen had a major effect in the biomass concentration of C. vulgaris, while no significant effect was found for phosphorus. Nitrogen and phosphorus starvation was found to be the strategy affecting the lipid accumulation and affected the lipid composition of C. vulgaris cultures.

Biological Responses of the marine diatom <i>Chaetoceros simplex </i> Ostenfeld to different treatments of phosphate and nitrate

Chaetoceros simplex Ostenfeld of marine diatoms was isolated and purified from the sub-surface waters of the north-western part of the Red Sea, Egypt (Hurgada). The isolated grown cells are exposed to different concentrations of nitrate and phosphate to estimate their effects on the growth and some metabolic activities of the organism. In general, the results indicated thatconcentrations of 100 μM nitrate and 5μM phosphate stimulated the algal growth by 60% and 32%, respectively in the 8 th day of culture. While, the values of 300 μM nitrate and 50 μM phosphate exhibited a decrease in the algal growth by 44% and 49%, respectively as compared with the control culture. The photosynthetic pigments (Chl-a, Chl-c and Carotenoids), total soluble proteins and carbohydrates of Chaetoceros simplex followed a similar pattern of change to that of growth in response to different treatments of nitrate and phosphate. While, the addition of different treatments of nitrate and phosphate to F/2 medium decreased the total lipids of C. simplex. Statistical analysis of the data indicated that 5 μM phosphates and 50 μM nitrates were the highly significant and most effective concentrations that positively affect most of different metabolic activities of Chaetoceros simplex . Thus, Chaetoceros simplex culture could be used as larval feed or other purposes cultured using 50 μM nitrate and 5μM phosphate .

Phytoremediation Potential of Three Species of Macrophytes for Nitrate in Contaminated Water

Three species of aquatic plants (Scirpus validus, Phragmites australis and Acorus calamus) were used as experimental materials to study their capacity to purify contaminated water and their effects on water pH and dissolved oxygen (DO). The water was contaminated with different concentrations of nitrate (5 mg/L, 15 mg/L and 25 mg/L). The results indicated that the concentration of nitrate, species of aquatic plant and their interaction significantly impacted denitrification (P = 0.00). Under the same concentrations, the three species of aquatic plants provided varying degrees of purification. Acorus calamus provided effective purification under all three concentrations of nitrate wastewater, with removal percentages of 87.73%, 83.80% and 86.72% for nitrate concentrations of 5 mg/L, 15 mg/L and 25 mg/L, respectively. In terms of the purification ability by unit fresh weight, Acorus calamus exhibited the worst purification capacity, whereas the capacities of Scirpus validus and Phragmites australis were higher. The purification capacity of Scirpus validus for the three concentrations was as follows: 0.08 mg/(L·g FW), 0.29 mg/(L·g FW), and 0.51 mg/(L·g FW). The capacity of Phragmites australis was 0.07 mg/(L·g FW), 0.25 mg/(L·g FW), and 0.53 mg/(L·g FW). The capacity of Acorus calamus was 0.04 mg/(L·g FW), 0.12 mg/(L·g FW), and 0.21 mg/(L·g FW). Under increased concentrations of nitrate, the three species of aquatic plants exhibited various degrees of increased purification capacity. Under the different concentrations of nitrate, the three species exhibited the same trends with respect to water pH and DO, increasing first and then falling. The pH remained at approximately 7.5, and the DO fell to 4.0 mg/L. A comprehensive analysis reveals that Acorus calamus provides excellent nitrate purification, although by unit fresh weight, both Scirpus validus and Phragmites australis provide superior purification capacity.

Production system and harvesting stage influence on nitrate content and quality of butterhead lettuce

Leafy vegetables such as lettuce grown under different production systems may accumulate different concentrations of nitrate which may reach to the levels potentially toxic to humans. Moreover, nitrate accumulation varies in various plant parts and physiological age of the plant. Therefore, to determine the effect of production system and harvesting stage on nitrate accumulation and quality of butterhead lettuce, a study was conducted considering two lettuce production systems namely hydroponic and organic, and four different harvesting stages such as 35, 38, 41 and 44 days after transplanting (DAT). The experimental design was complete randomized design (CRD) with four replications. Hydroponic and organic systems performed similar in terms of yield, quality and nitrate content of butterhead lettuce. Delaying harvesting can not only increase yield but also can minimize nitrate accumulation and health hazard risk as well. Delay in harvesting stage may result in quality deterioration of lettuce and increased production cost. Thus, a compromise is necessary to consider 41 DAT as the optimum stage to harvest butterhead lettuce with significantly higher reduction of nitrate content in both outer adult leaf blades and young leaves of hydroponic lettuce. Fresh weight, firmness and color of butterhead lettuce at this stage were still acceptable.

Effects of Nitrate and Salinity on Fatty Acid Composition of Marine Tetraselmis sp.: Potential as Biodiesel

Identifying sources of renewable energy is extremely important. The potential of Tetraselmis sp. in biodiesel production was investigated using a completely randomized design with four treatments. Te traselmis sp. was cultured on media containing different concentrations of nitrate there are 2 mM and 15 Mm and s 25 ‰ and 35 ‰ salinity. The treatments namely are (N 2 S 25 ), (N 2 S 35 ), N 15 S 25 ) and (N 15 S 35 ). Analysis of the fatty acid content using gas chromatography-mass spectrometry (GC-MS). The results show ed that the highest growth occurred in culture that contained 15 mM of nitrate and 35 ‰ salinity. The lowest growth occurred in culture containing 2 mM of nitrate and 25 ‰ of salinity. The highest lipid content was found in cultures containing 2 mM of nitrate and 25 ‰ salinity, it is 34.83%. Seven fatty acids were detected in culture containing 2 mM of nitrate and 25 ‰ salinity namely myristic acid (4.02%), palmitic acid (40.59%), palmitoleic acid (29.06%), stearic acid (0.95%), oleic acid (12.52%), gamma-linolenic acid (2.56%), and arachidonic acid (9.38%). Four fatty acids palmitoleic acid (8.99%), palmitic acid (37.34%), oleic acid(44.89%), and stearic acid (8.78%) were detected in 2 mM of nitrate with 35 ‰ salinity. The fatty acids have potential to be used as raw material for biodiesel production.

Investigating the effect of different concentrations of nitrate and phosphate on the quantity of mycosporine like amino acids production and growth in Spirulina platensis

The present study invested on the effect of different concentrations of NaNO3 (1.5, 2, 2.5 gl-1) and K2Hpo4 (0.04, 0.05, 0.06 gl -1 ) on chlorophyll a, carotenoids, fresh and dry weight measures, and the quality of mass absorption in Spirulina platensis alga. Findings revealed a significant increase in the amount of chlorophyll a and carotenoids in cultivation setting by increasing NaNO3 and K2HPO4, especially at 2.5gl -1 NaNo3 and 0.06 gl -1 K2Hpo4 concentrations. More findings also revealed that nitrate or phosphate supplemented growth medium had reducing effects on fresh weight; but, adversely affected the dry weight. Here, there was an increase in concentration of NaNO3 and K2HPO4, especially for 2.5 gl-1nitrateand 0.05 gl-1phosphate concentration samples. It should also be mentioned that the highest dry mass measures were obtained in 2.5 gl -1 NaNO3, though mass absorption in Spirulina platensis was at the highest rate in 2 gl-1 nitrate and 0.06 gl-1 phosphate concentration samples. Supplementary findings also indicated that quantities of mycosporine like amino acids (MAAs) increased significantly by increasing nitrate and phosphate concentrations. Collectively, it could be concluded that the altered composition of cultivation medium, especially macro elements like nitrate and phosphate, may affect the composition of quasi-mycosporine like amino acids by changing nitrogen assimilation, photosynthetic pigments content, which leads to probably higher photosynthesis and stimulating shikimate pathway.

Competition and facilitation between the marine nitrogen-fixing cyanobacterium Cyanothece and its associated bacterial community.

N2-fixing cyanobacteria represent a major source of new nitrogen and carbon for marine microbial communities, but little is known about their ecological interactions with associated microbiota. In this study we investigated the interactions between the unicellular N2-fixing cyanobacterium Cyanothece sp. Miami BG043511 and its associated free-living chemotrophic bacteria at different concentrations of nitrate and dissolved organic carbon and different temperatures. High temperature strongly stimulated the growth of Cyanothece, but had less effect on the growth and community composition of the chemotrophic bacteria. Conversely, nitrate and carbon addition did not significantly increase the abundance of Cyanothece, but strongly affected the abundance and species composition of the associated chemotrophic bacteria. In nitrate-free medium the associated bacterial community was co-dominated by the putative diazotroph Mesorhizobium and the putative aerobic anoxygenic phototroph Erythrobacter and after addition of organic carbon also by the Flavobacterium Muricauda. Addition of nitrate shifted the composition toward co-dominance by Erythrobacter and the Gammaproteobacterium Marinobacter. Our results indicate that Cyanothece modified the species composition of its associated bacteria through a combination of competition and facilitation. Furthermore, within the bacterial community, niche differentiation appeared to play an important role, contributing to the coexistence of a variety of different functional groups. An important implication of these findings is that changes in nitrogen and carbon availability due to, e.g., eutrophication and climate change are likely to have a major impact on the species composition of the bacterial community associated with N2-fixing cyanobacteria.

Nitrate Adsorption on Clay Kaolin: Batch Tests

Soils possessing kaolin, gibbsite, goethite, and hematite particles have been found to have a natural capacity to attenuate pollution in aqueous phase. On the other hand, the hydroxyl group in soil increases anion exchange capacity under a low pH condition. The main objective of this paper was to evaluate effects of kaolin on nitrate reduction under acidic condition. In order to analyze the kaolin adsorption behaviour under various conditions, four different concentrations of nitrate, 45, 112.5, 225, and 450 mgNO3-/L, with a constant pH equal to 2, constant temperature equal to 25°C, and exposure period varying from 0 to 150 minutes were considered. The capacity of nitrate adsorption on kaolin has also been studied involving two well-known adsorption isotherm models, namely, Freundlich and Longmuir. The results revealed that approximately 25% of the nitrate present in the solution was adsorbed on clay kaolin. The laboratory experimental data revealed that Freundlich adsorption isotherm model was more accurate than Longmuir adsorption model in predicting of nitrate adsorption. Furthermore, the retardation factor of nitrate pollution in saturated zone has been found to be approximately 4 in presence of kaolin, which indicated that kaolin can be used for natural scavenger of pollution in the environment.

Risk assessment of nitrate and petroleum-derived hydrocarbon addition on Contricriba weissflogii biomass, lifetime, and nutritional value

Coastal diatoms are often exposed to both petroleum-derived hydrocarbon pollution and eutrophication. How these exposures influence on algal biomass, lifetime, and nutritional value are unknown. To examine a more accurate risk assessment of the pollutants on the role of diatoms in coastal ecosystem functions, Conticribra weissflogii was maintained at different concentrations of nitrate (N) and/or water-soluble fractions of No.0 diesel oil (WSF). Algal density, cell growth cycle, protein, chlorophyll a, superoxide dismutase (SOD) activity, and malonaldehyde (MDA) were determined for the assessment of algal biomass, lifetime, nutritional value, photosynthesis and respiration, antioxidant capacity, and lipid peroxidation, respectively.When N addition was combined with WSF pollution, the cell growth cycles were shortened by 27–44%; SOD activities were decreased by 1–64%; algal density, the concentrations of chlorophyll a, protein, and MDA were varied between 38 and 310%, 62 and 712%, 4 and 124%, and 19 and 233% of the values observed in N addition experiments, respectively. Coastal ecosystem functions were severely weakened by N and WSF additions, and the influence was increased in the order: N<WSF<WSF+N. Thus, the simultaneous monitoring of N and WSF was necessary for the risk assessment of petroleum-derived hydrocarbon on coastal ecosystem functions.