柑桔园铁锌营养及配方施肥模型研究

采用五因素五水平二次回归最优旋转设计，对柑桔园铁锌营养及配方施肥模式进行了研究，并建立了碱性紫色土和中性紫色土温州蜜桔、锦橙，以产量为主要指标和黄红壤冰糖橙以叶片锌含量为主要指标的推荐施肥模式及参考施肥配方。

Distribution patterns of vegetation biomass and nutrients bio-cycle in alpine tundra ecosystem on Changbai Mountains,Northeast China

A study was conducted to test the correlation between biomass and elevation and the differences in concentration and storks of nutrients among five vegetation types （Felsenmeer alpine tundra vegetation-FA, Lithic alpine tundra vegetation-LA, Typical alpine tundra vegetation-TA, Meadow alpine tundra vegetation-MA, and Swamp alpine tundra vegetation-SA） on alpine tundra of Changbai Mountains, Jilin Province, China in growing seasons of 2003, 2004 and 2005. The biomass of 43 mono-species and soil nutrients in alpine tundra ecosystem were also investigated. Dominant species from Ericaceae （such as Rhododendron chrysanthum and Vaccinium jliginosum var. alpinum） were taken to analyze organ biomass distribution. Result showed that the biomass and elevation had a significant correlation （Biomass-237.3 in（Elevation） ＋494.36; R^2=0.8092; P〈0.05）. No significant differences were found in phosphorus and sulphur concentrations of roots, stems and leaves among the five vegetation types. There were significant differences in nitrogen and phosphorus stocks of roots, stems and leaves and in sulphur stock of stems and leaves among TA, MA, and SA vegetation types （p〈0.05）. The nutrient stock of five vegetations was averagely 72.46 kg.hm^-2, of which N, P, S were 48.55, 10.33 and 13.61 kg·hm^-2, respectively. Soil N and S concentrations in meadow alpine tundra soil type was significantly higher than those in other four soil types （Cold desert alpine tundra soil, Lithic alpine tundra soil, Peat alpine tundra soil, and Gray alpine tundra soil）. Phosphorous concentration in SA type was higher （p〈0.05） than in other types. Soil nutrient stock （0-20cm） was averagely 39.59 t.hm^-2, of which N, P, S were 23.74, 5.86, 9.99 t·hm^-2, respectively.

Biological Characteristics and Rumen Microorganisms of Gayal(Bos frontalis)in Yunnan Province

[Objective]The paper was to provide reference for further study and development of gayal（Bos frontalis）.[Method]According to the research status at home and abroad,the biological characteristics and rumen microorganisms of gayal in Yunnan Province was studied.[Result]Gayal in Yunnan had typical body form and very good meat production performance,its muscle fiber diameter was significantly less than other kinds of cattle;the water holding ratio,muscle tenderness and muscle succulency were significantly higher than others;its amount,shape and structure of chromosome were different from yellow cattle（Bos taurus）and wild cattle（Bos gaurus）,and the amounts of those chromosomes（2n）were 58,60 and 56,respectively.It could create hybrid with yellow cattle;the gayal＇s special diet was bamboo,its in vitro dry matter digestibility（IVDMD）on various crude forage was significantly higher than yellow cattle in Yunnan;the viable bacteria and cellulolytic bacteria in rumen were 4.51×109 and 1.63×109 CFU/ml,which was significantly higher than yellow cattle in Yunnan,its dominant bacteria in rumen mainly was cellulolytic bacteria.[Conclusion]Gayal not only had high academic value,but also had a great development value.

Responses of Picoplankton to Nutrient Perturbation in the South China Sea, with Special Reference to the Coast-wards Distribution of Prochlorococcus

Responses of Prochlorococcus (Pro), Synechococcus (Syn), pico-eukaryotes (Euk) and heterotrophic bacteria (Bact) in pelagic marine ecosystems to external nutrient perturbations were examined using nitrogen- (N), phosphorus- (P), iron- (Fe), and cobalt- (Co) enriched incubations in the South China Sea in November 1997. Variations in abundance of the 4 groups of microorganism and cellular pigment content of the autotrophs during incubation were followed by flow-cytometric measurements for seven days. During the incubation, Syn and Euk showed a relatively higher demand on Fe and N, while Pro required higher levels of Co and P. The Fe was inadequate for all the organisms in the deep euphotic zone (75 m) of the study area. The experimental results also implied that biological interaction among the organisms played a role in the community structure shift during the incubation. It seemed that besides the effects of temperature, there are some other physical and chemical limitations as well as impacts from biological interactions on Pro distribution in coast waters.

Effect of Fouling in Daya Bay Scallop chlamys nobilis (reeve) Cultivation:Food Competition and Nutrient Release

Biofouling is an important factor that affects bivalve farming industry. Fouling organisms may reduce growth and survival rate of the cultured species. Fouler are often filter feeders, so they are potential competitors for food resource with the cultured species. The present study was conducted to measure the impact of fouling on food uptake and nutrient release in April, 2006 in Daya Bay near Guangzhou, China. Results showed that fouling organisms had significant effect on food uptake and nutrient release. The chlorophyll a uptake rate of fouled scallops was 7.53 / Lh ±1.416 / Lh in April, significantly higher than those of cleaned scallops, Le., 4.23 / Lh±2.744 / Lh. The consumption of total particulate matter by fouled scallops in April was 5.52 / Lh± 0.818 / Lh; the corresponding results for cleaned scallops are 2.49 / Lh ±0.614 / Lh Fouling increased ammonia release significantly. The ammonia release rate of fouled scallops was 33.81/Lh ±7.699 / Lh in April, while cleaned scallops released 2.46 / Lh ±0.511 / Lh ammonia. Phosphate uptake of fouled scallops was 2.01± 0.699 / Lh and cleaned scallops released phosphate 6.01 / Lh ＋ 0.876 / Lh in April. There was not significant difference in nitrate consumption between fouled and cleaned scallops. According to the phytoplankton classification of input and output water samples, fouled scallops filtered more phytoplankton species than cleaned scallops. Therefore, this study showed that fouling contributed much to phytoplankton depletion and concentration increase of ammonia in water.

A Rapid Metagenomic DNA Extraction from Sediments: Potassium Dichromate SDS Method

[Objective] The objective of this study was to report an improved method for rapid DNA extraction from black-order sediments, without any purification step. [Methods] Sediments in eutrophic lake are complex ecosystems and soil microbes involved in anthropogenic nutrient cycling are very important. DNA-based molecular methods offer new tools for characterization of these mixed communities of mi- croorganisms. However, it is very difficult to remove humic substances, heavy met- als that co-existed with genome DNA representing the microbial community directly from these complex systems and can interfere with subsequent genetic analysis. The potassium dichromate solution was firstly used to remove humic substances. [Results] The steps of removing humic substances and DNA extraction were per- formed simultaneously that improved the speed of extraction to approximately 1 hour and the nucleic acids that were obtained with this method did not need to be washed with 70% ethanol and dissolved directly in sterile water for total bacterial 16S rDNA, nosZ gene of denitrifying bacteria, pmoA of methanotrophs, nifH of nitro- gen-fixing bacteria, amoA of ammonia-oxidizing bacteria and ammonia-oxidizing ar- chaea molecular ecology analyses. [Conclusion] This method could provide a plat- form for preparing a fast sediments DNA extraction.

A plant nutrition strategy for ex-situ conservation based on "Ecological Similarity"

This paper reviewed a large scale conservation work of rare and endangered plants currently conducted in main botanical gardens in China, and the existed, predictable and neglected problems on plant growth and reproduction in ex-situ conservation process. Considered the status quo in plant ex conservation, a nutritional strategy on the plant conservation was proposed based on ＇Ecological Similarity＇. Its main idea was that the ex-situ conservation plants coming from natural ecosystem were compulsively allocated in the agro-ecosystems and would return to natural ecosystem ultimately. Therefore, research on plant nutrition of the ex-situ conservation plants should neither just pursue yield and quality as that in agro-ecosystems nor merely stay on intrinsic natures without human intervening. We should give attentions to both of their attributes as in natural ecosystems and in agro-ecosystems, i.e., taking full advantage of plant nutritional measures as in agro-ecosystems to solve actual survival problems of the ex-conservation plants, and ensuring the final goal of returning to nature and playing its ecological role.

Effects of Transplanting Nutrient Soil on Growth and Dry Matter Accumulation of Tobacco Seedlings

In order to select the suitable soil for transplanting tobacco in Hunan to- bacco growing areas, pot experiment was conducted to study the effects of different transplanting nutdent soils on the growth and dry matter accumulation of tobacco. The results indicated that the treatments of transplanting with nutrition soils were better than the control group. For the underground part, transplanting nutrient soil could effectively improve the root activity of tobacco plants, and increase root volume, root surface area, total root length, as well as the number of root tips and the number of root branches. For the aboveground part, transplanting nutrient soil could remarkably improve the plant height, stem girth, leaf number and maximum leaf area, and could simultaneously significantly increase the dry matter accumulation. By comparison, peat ＋ mushroom residue ＋ saw dust ＋ straw powder ＋ bicchar ＋ root promoting nutrient solution was the most effective treatment, and the effect of sole application of nutrient solution was limited. In conclusion, transplanting with nutrition soil could effectively promote the growth and dry matter accumulation of tobacco.

Effects of Ca2+concentrations on accumulations of mineral elements in the components of Pteroceltis tatarinowii

The bark of Pteroceltis tatarinowii is a raw material for manufacturing Xuan Paper. The effects of Ca2+ concentrations on the accumulation of mineral elements in the bark, leaf and root of Pteroceltis tatarinowii were studied under controlled condi-tions. The types of Hoagland nutrient solution with three Ca2+ concentrations levels (200, 400 and 600 靏g-1) and a control (without Ca2+) were designed to culture Pteroceltis tatarinowii. After 6 months, contents of seven mineral elements including Ca, K, Mg, Mn, Zn, Cu and Na in the root, leaf and bark were analyzed. The results indicated that Ca accumulations content in the root, leaf and bark had positively relation with Ca2+ concentrations (200, 400, 600 靏g-1), and the order of the Ca content in the three components was root】leaf】bark. Ca content in the root treated with 600 靏g-1 Ca2+ concentrations was 5.5 times as high as that of the control, and about 1.4 times as high as that of the root treated in 200 and 400 靏/g Ca2+ concentrations respectively. On the contrary, K and Mg contents in the root, leaf and bark were negatively related to Ca2+ concentrations, especially in the bark, and their accumulation trend followed the order of leaf】root】bark. K content in the bark treated with 600 靏g-1 Ca2+ con-centrations was 39.3% of that of the control, and was 79.0% and 91.8% of that of the bark treated with 200 靏g-1 and 400靏g-1 Ca2+ concentrations respectively; Mg content in the bark treated with 600 靏g-1 Ca2+ concentrations was 23.4% of that of the control, and was 27.1% and 35.4% of that of the bark treated with 200 and 400 靏g-1 Ca2+ concentrations respectively. Com-pared with the control, the general tendency of Mn, Zn and Cu content decreased with increasing of Ca2+ concentrations and their contents were in the order: root】leaf】bark. Based on the results of this study, the experiment has been useful for providing academic bases in improving the bark quality of Pteroceltis tatarinowii on non-limestone soil.

Enhanced Biological Nutrients Removal in Modified Step-feed Anaerobic/Anoxic/Oxic Process

In order to enhance phosphorus removal in traditional step-feed anoxic/oxic nitrogen removal process,a modified pilot-scale step-feed anaerobic/anoxic/oxic(SFA 2/O) system was developed,which combined a reactor similar to UCT-type configuration and two-stage anoxic/oxic process.The simultaneous nitrogen and phosphorus removal capacities and the potential of denitrifying phosphorus removal,in particular,were investigated with four different feeding patterns using real municipal wastewater.The results showed that the feeding ratios(Q1)in the first stage determined the nutrient removal performance in the SFA 2/O system.The average phosphorus removal efficiency increased from 19.17% to 96.25% as Q1 was gradually increased from run 1 to run 4,but the nitrogen removal efficiency exhibited a different tendency,which attained a maximum 73.61%in run 3 and then decreased to 59.62%in run 4.As a compromise between nitrogen and phosphorus removal,run 3 (Q1=0.45Qtotal) was identified as the optimal and stable case with the maximum anoxic phosphorus uptake rate of 1.58 mg·(g MLSS)-1 ·h-1.The results of batch tests showed that ratio of the anoxic phosphate uptake capacity to the aerobic phosphate uptake capacity increased from 11.96% to 36.85% with the optimal influent feeding ratio to the system in run 3,which demonstrated that the denitrifying polyP accumulating organisms could be accumulated and contributed more to the total phosphorus removal by optimizing the inflow ratio distribution.However,the nitrate recirculation to anoxic zone and influent feeding ratios should be carefully controlled for carbon source saving.

Influences of enteral nutrition combined with probiotics on gut microflora and barrier function of rats with abdominal infection

AIM： To investigate the influences of enteral, parenteral nutrition and probiotics delivered by gut on intestinal microecology, epithelial tight junctions, immune and barrier function of rats with abdominal infection. METHODS： Rat abdominal infection models established with cecal ligation and perforation method, were divided into three groups： parenteral nutrition （PN group, n = 7）, PN＋enteral nutrition （EN group, n = 7） and PN ＋ EN ＋ probiotics （probiotics group, n = 7） via the needle jejunostomy and neck vein for five days. The total nutritional supplement of the three groups was isonitrogenic and isocaloric. Probiotics was delivered by jejunostomy 10 mL/d （1 x 10^8 cfu/mL）. The rats were killed on the sixth day. The feces in the cecum were cultured for anaerobic bacterial growth and analyzed with bacterial group DNA fingerprint profile with random amplified polymorphic DNA. The transmembrane binding proteins （occludin） and IgA level in plasma cells of intestine epithelium in colon and terminal ileum were measured by an immunohistochemistry method. The ultrastructure of intestinal epithelial tight junctions in colon and small intestine was observed by electronmicroscopy. Vena cava blood and the homogenated tissue of liver, lung and mesenteric lymph nodes were cultured to determine the bacterial translocations, and endotoxin in the blood from portal vein was detected. RESULTS： （1） The amount of bacteria of gut species in EN group and probiotic group was higher than that in PN group. The DNA-proflles in EN group and probiotic group were similar to that of normal rats. The number of DNAprofiles in probiotics group was much more than that in PN group and EN group. Moreover, there were strange stripes in PN group. （2） The expression of occludin and IgA in the small and large intestine in EN group （2.309 ± 0.336, 15.440 ± 2.383） and probiotic group （2.938 ± 0.515, 16.230 ± 3.183） was improved as compared with PN group （1.207 ± 0.587, P 〈 0.05, 11.189 ± 2.108, P 〈 0.01）. The expression of occludin in probiotic group （intestine： 2.93 ± 0.515; cecum： 3.40 ± 0.617） was higher than that in EN group （intestine： 2.309 ± 0.336; cecum： 2.076 ± 0.670; P 〈 0.05）. The expression of IgA, especially in EN group （intestine： 15.440 ± 2.383） and probiotic EN group （large intestine： 12.516 ± 1.542） significantly increased as compared with PN group （intestine： 11.189 ± 2.108; cecum： 10.160 ± 1.643; P 〈 0.01）. The intestinal epithelial tight junctions and microvilli of the probiotic group were more intact than those in the PN group. （3） The bacterial translocations in blood, liver, lung and mesenteric lymph nodes, and the levels of endotoxin were significantly reduced in probiotic （0.082 ± 0.029） and EN （0.125 ± 0.040） groups as compared with PN group （0.403 ± 0.181, P 〈 0.05）. CONCLUSION： Application of EN combined with probiotics could improve the expression of transmembrane binding proteins （occludin） and IgA, correct the intestinal flora disturbance, maintain gut barrier functions and tight junctions, and reduce the occurrence of gut bacterial translocation.

Fluidized-Bed Bioreactor Applications for Biological Wastewater Treatment： A Review of Research and Developments

Wastewater treatment is a process that is vital to protecting both the environment and human health. At present, the most cost-effective way of treating wastewater is with biological treatment processes such as the activated sludge process, despite their long operating times. However, population increases have created a demand for more efficient means of wastewater treatment, Fluidization has been demonstrated to in- crease the efficiency of many processes in chemical and biochemical engineering, but it has not been widely used in large-scale wastewater treatment. At the University of Western Ontario, the circulating fluidized-bed bioreactor （CFBBR） was developed for treating wastewater. In this process, carrier particles develop a biofilm composed of bacteria and other microbes. The excellent mixing and mass transfer characteristics inherent to fluidization make this process very effective at treating both municipal and industrial wastewater. Studies of lab- and pilot-scale systems showed that the CFBBR can remove over 90% of the influent organic matter and 80% of the nitrogen, and produces less than one-third as much biological sludge as the activated sludge process. Due to its high efficiency, the CFBBR can also be used to treat wastewaters with high organic solid concentrations, which are more difficult to treat with conventional methods because they require longer residence times; the CFBBR can also be used to reduce the system size and footprint. In addition, it is much better at handling and recovering from dynamic loadings （i.e., varying influent volume and concentrations） than current systems. Overall, the CFBBR has been shown to be a very effective means of treating wastewa- ter, and to be capable of treating larger volumes of wastewater using a smaller reactor volume and a shorter residence time. In addition, its compact design holds potential for more geographically localized and isolat- ed wastewater treatment systems.

Rheological and Structural Properties of Sea Cucumber Stichopus japonicus During Heat Treatment

Changes in tissue structure, rheological properties and water content of raw and heated sea cucumber meat were studied. Sea cucumber Stichopus japonicus was heated at 25℃, 70℃ and 100℃ water for 5 min. The structural changes were observed using a light microscope and the rheological parameters （rupture strength, adhesive strength and deformation） determined using a texture meter. Microscopic photograph revealed that the structural change of heated meat was greater than that of raw meat. The rupture strength, adhesive strength and deformation of raw meat were smaller than those of the heated meat. Meanwhile, rheological parameters showed positive correlation with heating temperature. These changes are mainly caused by thermal denaturation and gelatinization of collagen during heating. These changes were also evidenced in observations using a light microscope and differential scanning calorimetry.

Biomass and nutrient productivities ofTetraselmis chuii under mixotrophic culture conditions with various C：N ratios

Mass microalgal culture plays an irreplaceable role in aquaculture,but microalgal productivity is restricted by traditional autotrophic culture conditions.In the present study,a Tetraselmis chuii strain belonging to the phylum Chlorophyta was isolated from south Yellow Sea.The growth rate and biomass productivity of this strain was higher under mixotrophic conditions with different carbon:nitrogen(C:N)ratios than those under autotrophic conditions.When the C:N ratio was 16,the optical density and biomass productivity were 3.7-and 5-fold higher than their corresponding values under autotrophic culture conditions,respectively.Moreover,T.chuii synthesized more polysaccharides and total lipids under mixotrophic conditions.In addition,T.chuii cultured under mixotrophic conditions synthesized more types of fatty acids than autotrophic culture conditions.At a C:N ratio of 16,the percentage of C16:0 and C18:1 reached 30.08%and 24.65%of the total fatty acid(TFA) content,respectively.These findings may provide a basis for largescale mixotrophic culture of T.chuii,as a potential bait-microalga.

Effects of nutrients and light intensity on the growth and biochemical composition of a marine microalga Odontella aurita

Algal biotechnology has advanced greatly in the past three decades. Many microalgae are now cultivated to produce bioactive substances. Odontella aurita is a marine diatom industrially cultured in outdoor open ponds and used for human nutrition. For the first time, we have systematically investigated the effects of culture conditions in cylindrical glass columns and fiat-plate photobioreactors, including nutrients （nitrogen, phosphorus, silicon, and sulfur）, light intensity and light path, on O. aurita cell growth and biochemical composition （protein, carbohydrate, β-1,3-glucan, lipids, and ash）. The optimal medium for photoautotrophic cultivation of O. aurita contained 17.65 mmol/L nitrogen, 1.09 mmol/L phosphorus, 0.42 mmol/L silicon, and 24.51 mmol/L sulfur, yielding a maximum biomass production of 6.1-6.8 g/L and 6.7-7.8 g/L under low and high light, respectively. Scale-up experiments were conducted with fiat-plate photobioreactors using different light-paths, indicating that a short light path was more suitable for biomass production of O. aurita. Analyses of biochemical composition showed that protein content decreased while carbohydrate （mainly composed of 15-1,3-glucan） increased remarkably to about 50% of dry weight during the entire culture period. The highest lipid content （19.7% of dry weight） was obtained under 0.11 mmol/L silicon and high light conditions at harvest time. Fatty acid profiles revealed that 80% were Cx4, C^6, and C20, while arachidonic acid and eicosapentaenoic acid （EPA） accounted for 1.6%-5.6% and 9%-20% of total fatty acids, respectively. High biomass production and characteristic biochemical composition profiles make O. aurita a promising microalga for the production ofbioactive components, such as EPA and D-1,3-glucan.

Preliminary Study on Biological Control of Cyclops of Zooplankton in Drinking Water Source

An ecological project called fish biomanipulation, other than the conventional fishery culture technique, was put forward in this paper for the excess propagation control of Cyclops. The control effects on Cyclops of four species of fish were investigated experimentally at stocking density of 30 g per cubic meter of water. The experimental results showed that the food habit of the fish had significant influence on the biological control of Cyclops. The propagation of Cyclops could be controlled effectively and also the water quality was improved simultaneously by stocking the filter-feeding fishes, such as silver carp and bighead carp. Whereas, herbivorous Ctenopharyugodon idellus and omnivorous Cyprinus carpio had no obvious biological effects on controlling the growth of Cyclops and restoring water quality. The results further proved that under condition of proper poly-culture density of silver carp and bighead carp, the number of Cyclops might be controlled at very low level and the eutrophication might be abated by removing the nutrients from water body.

Performance evaluation of a modified step-feed anaerobic/anoxic/oxic process for organic and nutrient removal

A pilot scale modified step-feed process was lmproved to increase nutrient/N ano P） ano organic removal operations from municipal wastewater. It combined the step-feed process and a method named ＂University of Cape Town （UCT）＂. The effect of nutrient ratios and inflow distribution ratios were studied. The highest uptake efficiency of 95% for chemical oxygen demand （COD） has been achieved at the inflow distribution ratio of 40/35/25. However, maximum removal efficiency obtained for total nitrogen （TN） and phosphorus at 93% and 78%, respectively. The average mixed liquor suspended solids （MLSS） was 5500 mg·L- 1. In addition, convenient values for dissolved oxygen （DO） concentration, and pH were obtained throughout different stages. The proposed system was identified to be an appropriate enhanced biological nutrient removal process for wastewater treatment plants owing to relatively high nutrient removal, sturdy sludge settle ability and COD removal.

Effects of modified clay flocculation on major nutrients and diatom aggregation during Skeletonema costatum blooms in the laboratory

Harmful algal blooms(HABs) can elicit several negative effects on aquatic environment(such as depleting the oxygen, blocking the sunlight, destroying the habitats of organisms) and life health(including poisoning/killing marine mammals, birds and human). Among the various control strategies for HABs(physical manipulation needs lots of manpower and expensive equipment, chemicals treatment has some toxic byproduct and high residual, microbial agents only has limited in laboratory research), the coagulation-flocculation of HAB species by modified clay(MC) has been proven to be an effective, lowcost and environmentally friendly method that has been widely applied in the field, particularly in eastern Asia. In order to examine the long-term effects of MC treatment, this study investigated the alternations in seawater of Skeletonema costatum, a high biomass dominant HAB species along the Chinese coast, by comparing the degradation of S. costatum detritus(A1) with the application of MC treatment(A2) and MC treatment in sediment condition(A3). The low dosage of 0.25 g/L MC could efficiently remove 4×108 cells/L of S. costatum cells within 3.5 h(approximately 97% removal). In addition, the results showed that both inorganic and organic nutrients were effectively reduced from seawater by MC particles. Compared to the total nitrogen(TN) and total phosphorus(TP) concentrations in A1 seawater, 44% of TN and 93% of TP in A2 seawater, as well as 72% of TN and 93% of TP in A3 seawater were removed during the onemonth incubation period. Simultaneously, 64% of DISi in A2 and 44% of DISi in A3 significantly decreased( P <0.001). This study demonstrated that MC treatment was able to significantly increase the downward flux of nutrients and delay the release velocity of inorganic nutrient from MC-algae matrix into the overlying seawater, particularly within sediment environment.

Brain-derived neurotrophic factor(BDNF) as a potential mechanism of the effects of acute exercise on cognitive performance

The literature shows that improvements in cognitive performance may be observed following an acute bout of exercise. However, evidence in support of the biological mechanisms of this effect is still limited. Findings from both rodent and human studies suggest brain-derived neu- rotrophic factor （BDNF） as a potential mechanism of the effect of acute exercise on memory. The molecular properties of BDNF allow this protein to be assessed in the periphery （pBDNF） （i.e., blood serum, blood plasma）, making measurements of acute exercise-induced changes in BDNF concentration relatively accessible. Studies exploring the acute exercise--pBDNF--cognitive performance relationship have had mixed findings, but this may be more reflective of methodological differences between studies than it is a statement about the role of BDNE For example, significant associations have been observed between acute exercise-induced changes in pBDNF concentration and cognitive performance in studies assessing memory, and non-significant associations have been found in studies assessing non-memory cognitive domains. Three suggestions are made for future research aimed at understanding the role of BDNF as a biological mechanism of this relationship： 1） Assessments of cognitive performance may benefit from a focus on various types of memory （e.g., relational, spatial, long-term）; 2） More finegrained measurements of pBDNF will allow for the assessment of concentrations of specific isoforms of the BDNF protein （i.e., immature, mature）; 3） Statistical techniques designed to test the mediating role of pBDNF in the acute exercise-cognitive performance relationship should be utilized in order to make causal inferences.

Characteristics of the δ15NNO3 distribution and its drivers in the Changjiang River estuary and adjacent waters

In this study, we conducted investigations in the Changjiang （Yangtze） River estuary and adjacent waters （CREAW） in June and November of 2014. We collected water samples from different depths to analyze the nitrogen isotopic compositions of nitrate, nutrient concentrations （including inorganic N, P, and Si）, and other physical and biological parameters, along with the vertical distribution and seasonal variations of these parameters. The compositions of nitrogen isotope in nitrate were measured with the denitrifier method. Results show that the Changjiang River diluted water （CDW） was the main factor affecting the shallow waters （above 10 m） of the CREAW, and CDW tended to influence the northern areas in June and the southern areas in November. 615Nrqo~ values in CDW ranged from 3.21%o-3.55%o. In contrast, the deep waters （below 30 m） were affected by the subsurface water of the Kuroshio Current, which intruded into the waters near 3 I^N in June. The ~iI^NNo3 values of these waters were 6.03%0-7.6%0, slightly higher than the values of the Kuroshio Current. Nitrate assimilation by phytoplankton in the shallow waters of the study area varied seasonally. Because of the favorable temperature and nutrient conditions in June, abundant phytoplankton growth resulted in harmful algae blooms （HABs）. Therefore, nitrate assimilation was strong in June and weak in November. The ~15NNo3 fractionations caused by assimilation of phytoplankton were 4.57%0 and 4.41%o in the shallow waters in June and November, respectively. These results are consistent with previous laboratory cultures and in situ investigations. Nitrification processes were observed in some deep waters of the study area, and they were more apparent in November than in June. The fractionation values of nitrification ranged from 24%0-25%o, which agrees with results for Nitrosospira tenuis reported by previous studies.