Effects of exposure to four endocrine disrupting-chemicals on fertilization and embryonic development of Barbel chub (Squaliobarbus curriculus)

The toxicities of 4 common endocrine-disrupting chemicals (EDCs), 17β-estradiol (E2), p,p′-dichlorodiphenyldichloro-ethylene (DDE), 4-nonylphenol (NP) and tributyltin (TBT), to sperm motility, fertilization rate, hatching rate and embryonic development of Barbel chub (Squaliobarbus curriculus) were investigated in this study. The duration of sperm motility was significantly shortened by exposure to the EDCs at the threshold concentrations of 10 ng L^?1 for E2 and TBT, 1 μg L^?1 for NP and 100 μg L^?1 for DDE, respectively. The fertilization rate was substantially reduced by the EDCs at the lowest observable effect concentrations (LOECs) of 10 ng L^?1 for E2 and TBT and 10 μg L^?1 for DDE and NP, respectively. Of the tested properties of S. curriculus, larval deformity rate was most sensitive to EDC exposure and was significantly increased by DDE at the lowest experimental level of 0.1 μg L^?1. Other EDCs increased the larval deformity rate at the LOECs of 1 ng L^?1 for E2, 10 ng L^?1 for TBT and 1 μg L^?1 for NP, respectively. Despite their decreases with the increasing EDC concentrations, the hatching rate and larval survival rate of S. curriculus were not significantly affected by the exposure to EDCs. The results indicated that all the 4 EDCs affected significantly and negatively the early life stages of the freshwater fish S. curriculus. Overall, E2 and TBT were more toxic than NP and DDE, while DDE might be more toxic to larval deformity rate than to other measured parameters. Thus, the 4 EDCs showed potential negative influences on natural population dynamics of S. curriculus. Our findings provided valuable basic data for the ecological risk assessment of E2, DDE, NP and TBT.     

Inorganic carbon parameters responding to summer hypoxia outside the Changjiang Estuary and the related implications

The eutrophication, hypoxia and coastal acidification are attracting more and more attention. In this study, inorganic carbon parameters, including dissolved inorganic carbon (DIC), total alkalinity (TA) and calculated partial pressure of CO₂ (pCO₂), obtained from a summer cruise in August, 2009, were used to investigate their integrated response to biological processes accompanying the oxygen depletion in the areas off the Changjiang Estuary. According to the observations, the typical hypoxia occurred in the bottom water just outside the Changjiang Estuary with Dissolved Oxygen (DO) lower than 2.00 mg L^?1. The biological uptake in the surface water and the decomposition of organic matter in the bottom water were fully coupled with each other. The high concentration of Chl_a (Chl_a = 10.9 μg L^?1) and DO (9.25 mg L^?1), profoundly decreased DIC concentration (1828 μmol kg^?1) and elevated pH (8.42) was observed in the surface water. The correspondingly increased DIC and depletion of oxygen were observed in the bottom water. The semi-quantitative analysis proved that the locally-produced phytoplankton, determined by primary productivity, was deposited to the bottom and contributed about 76% of total amount of the organic carbon decomposition in the bottom. However, in the bottom hypoxia (DO = 2.05 mg L^?1) area observed in the Southern Zhejiang coastal water, the responding patterns of inorganic carbon parameters deviated from the previous one. The expanding of Changjiang Diluted Water (CDW), the adding of Hangzhou Bay water (with high DIC concentration) and Coastal Current together modify the DIC background value in this area, and the local degeneration and upwelling process may also help to offset the local DIC removed by net biological uptake in surface water. In addition, when the mixing occurring in autumn, which may break the summer stratification, the excess release of high DIC in the bottom water to the subsurface water could have an important influence on coastal acidification and the CO₂ uptake capacity in this area.     

Distributions and Relationships of CO<Subscript>2</Subscript>, O<Subscript>2</Subscript>, and Dimethylsulfide in the Changjiang (Yangtze) Estuary and Its Adjacent Waters in Summer

The distributions and relationships of O₂, CO₂, and dimethylsulfide (DMS) in the Changjiang (Yangtze) Estuary and its adjacent waters were investigated in June 2014. In surface water, mean O₂ saturation level, partial pressure of CO₂ (pCO₂), and DMS concentrations (and ranges) were 110% (89%–167%), 374 μatm (91–640 μatm), and 8.53 nmol L^?1 (1.10–27.50 nmol L^?1), respectively. The sea-to-air fluxes (and ranges) of DMS and CO₂ were 8.24 μmol m^?2 d^?1 (0.26–62.77 μmol m^?2 d^?1), and ?4.7 mmol m^?2 d^?1 (?110.8-31.7 mmol m^?2 d^?1), respectively. Dissolved O₂ was oversaturated, DMS concentrations were relatively high, and this region served as a sink of atmospheric CO₂. The pCO₂ was significantly and negatively correlated with the O₂ saturation level, while the DMS concentration showed different positive relationships with the O₂ saturation level in different water masses. In vertical profiles, a hypoxic zone existed below 20 m at a longitude of 123°E. The stratification of temperature and salinity caused by the Taiwan Warm Current suppressed seawater exchange between upper and lower layers, resulting in the formation of a hypoxic zone. Oxidative decomposition of organic detritus carried by the Changjiang River Diluted Water (CRDW) consumed abundant O₂ and produced additional CO₂. The DMS concentrations decreased because of low phytoplankton biomass in the hypoxic zone. Strong correlations appeared between the O₂ saturation level, pCO₂ and DMS concentrations in vertical profiles. Our results strongly suggested that CRDW played an important role in the distributions and relationships of O₂, CO₂, and DMS.     

Effects of sodium nitrate and sodium acetate concentrations on the growth and fatty acid composition of <Emphasis Type="Italic">Brachiomonas submarina</Emphasis>

One isolate of Brachiomonas submarina was tested for its ability to grow heterotrophicly on 5 different organic compounds. Sodium acetate and glucose were found to be effective in supporting the growth. Sodium acetate was chosen as the organic nutrient to test the combined effects of organic and inorganic solutions on the growth and fatty acid composition of Brachiomonas submarina. The best growth rates were achieved at 3 mmol L⁻¹ CH₃COONa and 0.88 mmol L⁻¹ NaNO₃ in heterotrophic condition, and 4 mmol L⁻¹ CH₃COONa and 3.52 mmol L⁻¹ NaNO₃ in mixotrophic condition. The differences between fatty acid contents were significant. The total polyunsaturated fatty acids (T. P. U. F. As) varied from 55.79% to 67.72% in heteritrophic growth and from 52.39% to 65.55% in mixotrophic growth. It is concluded that CH₃COONa and NaNO₃ at 3 mmol L⁻¹ and 3.52 mmol L⁻¹ should respectively be used in order to achieve the highest growth rate and fatty acid content.     

The effect of chemical cues on the settlement of sea cucumber (Apostichopus japonicus) larvae

The effects of four ions and eight neuroactive compounds on inducing larval settlement of A. japonicus were assessed in the present study. All bioassays were conducted in 60 × 9 mm Petri dishes, each contained 10 mL of the test solution and 10 doliolaria larvae. There were significant inductive effects of K+(10- mmol L-1), NH+4(0.1 mmol L1), GABA(10-3 mol L-1), acetylcholine(10-5 mol L-1), L-DOPA(10-5 mol L-1), norepinephrine(10-5 mol L-1) and dopamine(10-7 mol L-1 and 10-5 mol L-1) on the settlement of sea cucumber larvae. L-DOPA and dopamine are the most efficient chemical cues to induce A. japonicus larvae to settle. The highest percentage of larval settlement was induced by 10-5 mol L-1 L-DOPA and dopamine(33% and 40%) compared to the control(7%). However, Ca2+, Mg2+, choline, serotonin, and epinephrine were less effective on larval settlement at all tested concentrations. This study evaluated the stability and feasibility of chemical cues for larval settlement in different culture systems, which can be applied to improve the hatchery production of this valuable species.     

An investigation on tolerance and accumulation of a facultative marine fungus <Emphasis Type="Italic">Aspergillus flavus</Emphasis> to pentavalent arsenic

Tolerance of a facultative marine fungus Aspergillus flavus towards As (V) was tested. Luxuriant growth of the test isolate was observed in culture media with As (V) concentrations of 25 mg L⁻¹ and 50 mg L⁻¹, indicating its tolerance to the metal. Accumulation rate of arsenic was always higher when exposed to As (V) at 50 mg L⁻¹ than at 25 mg L⁻¹. The study reveals Aspergillus flavus as a promising candidate for environmental bioremediation. Arsenic contents (mg g⁻¹) in the fungus when exposed to 50 mg L⁻¹ As (V) were measured as 11.1773, 4.0983, and 8.0000 mg g⁻¹ on day 3, 6 and 9, respectively. The highest content was observed initially, i.e. on day 3, followed by a decline and a rise again. These results provide baseline information for further explorations regarding the exploitation of the fungus for arsenic removal.     

Effect of benzo[a]pyrene on detoxification and the activity of antioxidant enzymes of marine microalgae

The objective of this study was to examine the effect of benzo[a]pyrene(Ba P) on the detoxification and antioxidant systems of two microalgae,Isochrysis zhanjiangensis and Platymonas subcordiformis.In our study,these two algae were exposed to Ba P for 4 days at three different concentrations including 0.5 μg~(L-1)(low),3 μg~(L-1)(mid) and 18 μg~(L-1)(high).The activity of detoxification enzymes,ethoxyresorufin O-deethylase(EROD) and glutathione S-transferase(GST) increased in P.subcordiformis in all Ba P-treated groups.In I.zhanjiangensis,the activity of these two enzymes increased at the beginning of exposure,and then decreased in the groups treated with mid-and high Ba P.The activity of antioxidant enzyme superoxide dismutase(SOD) increased in I.zhanjiangensis in all Ba P-treated groups,and then decreased in high Ba P-treated group,while no significant change was observed in P.subcordiformis.The activity of antioxidant enzyme catalase(CAT) increased in I.zhanjiangensis and P.subcordiformis in all Ba Ptreated groups.The content of malondialdehyde(MDA) in Isochrysis zhanjiangensis increased first,and then decreased in high Ba P-treated group,while no change occurred in P.subcordiformis.These results demonstrated that Ba P significantly influenced the activity of detoxifying and antioxidant enzymes in microalgae.The metabolic related enzymes(EROD,GST and CAT) may serve as sensitive biomarkers of measuring the contamination level of Ba P in marine water.     

The influence of key environmental variables on phytoplankton community structure in the estuary of tidal rivers around Luoyuan Bay,China

A total of 348 species belonging to 8 phyla and 125 genera were observed in seasonally sampled phytoplankton of tidal rivers from 13 sampling sites around Luoyuan Bay, and all field samplings were carried out in productive period(March/June/August/December) at ebb tide. Bacillariophyta species were the most abundant species, followed by Chlorophyta, Cyanophytes, Euglenophyta, Cryptophyta, Dinophyta, Xanthophyta and Chrysophytas. Seasonal distribution index(SDI) value ranged from 0.63 to 0.86, which meant that species found at those sites in 4 seasons tended to be largely different. Phytoplankton individuals ranged from 5.939×10~4 ind L~(-1) in winter to 75.31×10~4 ind L~(-1) in autumn. Phytoplankton biomass ranged from 0.620 mg L~(-1) in summer to 2.373 mg L~(-1) in autumn. The grey correlation analysis(GCA) showed that the nutrient variables played an important role in the influence on phytoplankton community in every season. The canonical correspondence analysis(CCA) revealed impact of environmental variables on the different species, most of Bacillariophyta species were negative correlation with nutrients(TP and NH_3-N) in the four seasons, Chlorophyta species and Cyanophyta species did not show obvious correlation with environment variables in every season. The combination of GRA analysis and CCA analysis provided a method to quantitatively reveal the correlation between phytoplankton community and environmental variables in water body of tidal rivers at this region.     

Effect of dissolved oxygen on swimming ability and physiological response to swimming fatigue of whiteleg shrimp (Litopenaeus vannamei)

The swimming endurance of whiteleg shrimp(Litopenaeus vannamei, 87.66 mm ± 0.25 mm, 7.73 g ± 0.06 g) was examined at various concentrations of dissolved oxygen(DO, 1.9, 3.8, 6.8 and 13.6 mg L-1) in a swimming channel against one of the five flow velocities(v1, v2, v3, v4 and v5). Metabolite contents in the plasma, hepatopancreas and pleopods muscle of the shrimp were quantified before and after swimming fatigue. The results revealed that the swimming speed and DO concentration were significant factors that affected the swimming endurance of L. vannamei. The relationship between swimming endurance and swimming speed at various DO concentrations can be described by the power model(ν·tb = a). The relationship between DO concentration(mg L-1) and the swimming ability index(SA∫ 9000I), defined as SAI =vdt( cm), can be described as SAI = 27.947 DO0.137(R2 = 0.9312). The 0level of DO concentration directly affected the physiology of shrimp, and exposure to low concentrations of DO led to the increases in lactate and energetic substrate content in the shrimp. In responding to the low DO concentration at 1.9 mg L-1 and the swimming stress, L. vannamei exhibited a mix of aerobic and anaerobic metabolism to satisfy the energetic demand, mainly characterized by the utilization of total protein and glycogen and the production of lactate and glucose. Fatigue from swimming led to severe loss of plasma triglyceride at v1, v2, and v3 with 1.9 mg L-1 DO, and at v-11 with 3.8, 6.8 and 13.6 mg L DO, whereas the plasma glucose content increased significantly at v3, v4 and v5 with 3.8 and 6.8 mg L-1 DO, and at v5 with 13.6 mg L-1 DO. The plasma total protein and hepatopancreas glycogen were highly depleted in shrimp by swimming fatigue at various DO concentrations, whereas the plasma lactate accumulated at high levels after swimming fatigue at different velocities. These results were of particular value to understanding the locomotory ability of whiteleg shrimp and its physiological changes, further contributing to the improvement of capture and rearing technique.     

An approach to determination of phenolic compounds in seawater using SPME-GC-MS based on SWCNTs coating

Phenolic compounds have become one kind of the important pollutants of the marine environment. Single-walled Carbon nanotubes, as one-dimensional nano materials, have light weight and perfect hexagonal structure of connections, with many unusual mechanical, chemical and electrical properties. In recent years, with the research of carbon nanotubes and other nano materials, the application prospect is also constantly discussed. In this paper, homemade single-walled carbon nanotubes(SWCNTs) coating was used for establishing an analytical approach to the determination of five kinds of phenolic compounds in seawater using SPME-GC-MS. Optimal conditions: After saturation was conducted with Na Cl, and p H was adjusted to 2.0 with H_2SO_4, the extract was immersed in a water bath at 40 for GC℃-MS determination through 40-min agitating extraction at 500 rmin~(-1) and 3-min desorption at 280℃. The liniearities ranged between 0.01-100 μg L~(-1), and the determination limits ranged between 1.5-10 ngL~(-1). The relative standard deviation(RSD, n = 5) was less than 6.5%. For the phenolic compounds obtained from the spiked recovery test for actual seawater samples, the rates of recovery were 87.5%-101.7%, and the RSDs were less than 8.8%, which met the requirements of determination. Due to its simplicity, high efficiency and low consumption, this approach is suitable for the analysis of trace amounts of phenolic compounds in marine waters.     

Exploration of Antifouling Potential of the Brown Algae <Emphasis Type="Italic">Laminaria</Emphasis> ‘Sanhai’

Seaweeds are one of the largest producers of biomass in the marine environment. It has been well known that marine algae, especially brown algae was a rich source of biogenic compounds with antifouling potential that could be ideal alternatives of tributyltin (TBT). In this paper, antifouling potential of the brown algae Laminaria ‘sanhai’ was explored. Firstly, the dried alga was extracted and the antialgal and antilarval activities were investigated. The EC₅₀ and LC₅₀ values of crude extract of Laminaria ‘sanhai’ against diatom (Skeletonema costatum) and barnacle larval (Chthamalus challengeri) were 8.9 μg mL^?1 and 12.0 μg mL^?1 respectively. Then, guided by bioassay, the bioactive substances were isolated by liquid-liquid extraction. The antialgal and antilarval activities of isolated fraction were improved with the EC₅₀ value of 7.4 μg mL^?1 against S. costatum and LC₅₀ value of 9.7 μg mL^?1 against C. challengeri larvae. Identification by IR, Q-TOFMS and GC-MS of the isolated bioactive substances revealed the abundance of fatty acids. These fatty acids, most with 16, 18 or 20 carbon atoms, contained myristic, hexadecanoic, oleic, linolenic, arachidonic and eicosapentaenoic acids. The results indicated that both the crude extract and the isolated bioactive substances had high antialgal and antilarval activities with no highlighted cytotoxicity which made the brown algae Laminaria ‘sanhai’ a promising source of the environmentally friendly antifoulants.     

Effects of nitrogen and phosphorus on the growth of <Emphasis Type="Italic">Levanderina fissa</Emphasis>: How it blooms in Pearl River Estuary

Effects of nitrogen (N) and phosphorus (P) from different sources and at different concentrations on the growth of Levanderina fissa (= Gyrodinium instriatum) were studied in laboratory conditions. The findings might explain the recurrent blooms of this species in Pearl River Estuary, China. Results showed that nutrient limitation significantly inhibited the growth of L. fissa. The values of specific growth rate (μ _max) and half-saturation nutrient concentration (K _S) were 0.37 divisions/d and 8.49 μmol L^?1 for N, and 0.39 divisions/d and 1.99 μmol L^?1 for P, respectively. Based on K _S values, dissolved inorganic N level in PRE was sufficient to support the high proliferation of L. fissa, while dissolved inorganic P concentration was far lower than the minimum requirement for its effective growth. L. fissa was not able to utilize dissolved organic N (DON) compounds such as urea, amino acids, and uric acid. However, it grew well by using a wide variety of dissolved organic P (DOP) sources like nucleotides, glycerophosphate, and 4-nitrophenylphosphate. The results from this study suggested that the ability in DOP utilization of L. fissa offers this species a competitive advantage in phytoplankton communities. The high level and continuous supply of DIN, enrichment of DOP, together with warm climate and low salinity in the Pearl River Estuary provided a suitable nutrient niche for the growth of L. fissa, and resulted in the recurrent blooms in the estuary.     

Antifouling potential of bacteria isolated from a marine biofilm

Marine microorganisms are a new source of natural antifouling compounds. In this study, two bacterial strains, Kytococcus sedentarius QDG-B506 and Bacillus cereus QDG-B509, were isolated from a marine biofilm and identified. The bacteria fermentation broth could exert inhibitory effects on the growth of Skeletonema costatum and barnacle larvae. A procedure was employed to extract and identify the antifouling compounds. Firstly, a toxicity test was conducted by graduated pH and liquid-liquid extraction to determine the optimal extraction conditions. The best extraction conditions were found to be pH 2 and 100% petroleum ether. The EC50 value of the crude extract of K. sedentarius against the test microalgae was 236.7 ± 14.08 μg mL-1, and that of B. cereus was 290.6 ± 27.11 μg mL-1. Secondly, HLB SPE columns were used to purify the two crude extracts. After purification, the antifouling activities of the two extracts significantly increased: the EC50 of the K. sedentarius extract against the test microalgae was 86.4 ± 3.71 μg mL-1, and that of B. cereus was 92.6 ± 1.47 μg mL-1. These results suggest that the metabolites produced by the two bacterial strains are with high antifouling activities and they should be fatty acid compounds. Lastly, GC-MS was used for the structural elucidation of the compounds. The results show that the antifouling compounds produced by the two bacterial strains are myristic, palmitic and octadecanoic acids.     

Study on the Preparation and Antileukemic Activity of New Lipophilic 1-β-D-arabinofuranosylcytosine Derivatives

Cytarabine(1-β-D-arabinofuranosylcytosine, Ara-C), isolated from a Caribbean sponge species Tethyacrypta, is the first antitumor drug from a marine resource. In 1980, the US Food and Drug Administration approved this drug for the treatment of different types of leukemia. This drug has a short plasma half-life, low stability, limited bioavailability, and severe side effects. To improve stability and bioavailability, we synthesized nine novel derivatives by blocking the cytarabine metabolic sites and improving lipophilicity. The c Log P values of the newly synthesized compounds were calculated. All the synthesized compounds were more lipophilic than cytarabine, resulting in membrane permeability and bioavailability improvement. The antitumor activities against leukemia cell line HL-60 were evaluated by using the MTT assay. The bioassay results revealed that the IC_(50) values of compounds 5, 8 and 9 were 0.080, 0.090 and 0.057 μmol L~(-1), respectively, which was similar with that of cytarabine(0.056 μmol L~(-1),). In comparison, compound 4 with a phosphate group at O5' was inactive. Because phosphoester bonds are easily hydrolyzed by alkaline phosphatase and are commonly used in producing prodrug strategies, compound 4 might also be metabolized in vivo and generate compound 3 or even cytarabine through a multi-step reaction. Thus, compound 4 might be a promising compound to be developed as a prodrug.     

Optimization of culture conditions and medium composition for the marine algicidal bacterium Alteromonas sp. DH46 by uniform design

Harmful algal blooms (HABs) have led to extensive ecological and environmental issues and huge economic losses. Various HAB control techniques have been developed, and biological methods have been paid more attention. Algicidal bacteria is a general designation for bacteria which inhibit algal growth in a direct or indirect manner, and kill or damage the algal cells. A metabolite which is strongly toxic to the dinoflagellate Alexandrium tamarense was produced by strain DH46 of the alga-lysing bacterium Alteromonas sp. The culture conditions were optimized using a single-factor test method. Factors including carbon source, nitrogen source, temperature, initial pH value, rotational speed and salinity were studied. The results showed that the cultivation of the bacteria at 28°C and 180 r min^?1 with initial pH 7 and 30 salt contcentration favored both the cell growth and the lysing effect of strain DH46. The optimal medium composition for strain DH46 was determined by means of uniform design experimentation, and the most important components influencing the cell density were tryptone, yeast extract, soluble starch, NaNO₃ and MgSO₄. When the following culture medium was used (tryptone 14.0g, yeast extract 1.63g, soluble starch 5.0 g, NaNO₃ 1.6 g, MgSO₄ 2.3 g in 1L), the largest bacterial dry weight (7.36 g L^?1) was obtained, which was an enhancement of 107% compared to the initial medium; and the algal lysis rate was as high as 98.4% which increased nearly 10% after optimization.     

Antialgal and antilarval activities of bioactive compounds extracted from the marine dinoflagellate <Emphasis Type="Italic">Amphidinium carterae</Emphasis>

With the global ban on the application of organotin-based marine coatings by the International Maritime Organization, the development of environmentally friendly, low-toxic and nontoxic antifouling compounds for marine industries has become an urgent need. Marine microorganisms have been considered as a potential source of natural antifoulants. In this study, the antifouling potential of marine dinoflagellate Amphidinium carterae, the toxic and red-tide microalgae, was investigated. We performed a series of operations to extract the bioactive substances from Amphidinium carterae and tested their antialgal and antilarval activities. The crude extract of Amphidinium carterae showed significant antialgal activity and the EC₅₀ value against Skeletonema costatum was 55.4 μg mL^?1. After purification, the isolated bioactive substances (the organic extract C) exhibited much higher antialgal and antilarval activities with EC₅₀ of 12.9 μg mL^?1 against Skeletonema costatum and LC₅₀ of 15.1 μg mL^?1 against Amphibalanus amphitrite larvae. Subsequently, IR, Q-TOFMS, and GC-MS were utilized for the structural elucidation of the bioactive compounds, and a series of unsaturated and saturated 16- to 22-carbon fatty acids were detected. The data suggested the bioactive compounds isolated from Amphidinium carterae exhibited a significant inhibiting effect against the diatom Skeletonema costatum and Amphibalanus amphitrite larvae, and could be substitutes for persistent, toxic antifouling compounds.     

Biosorption of Cd (Ⅱ) and Pb (Ⅱ) Ions by Aqueous Solutions of Novel Alkalophillic Streptomyces VITSVK5 spp. Biomass

Discharge of heavy metals from metal processing industries is known to have adverse effects on the environment. Biosorption of heavy metals by metabolically inactive biomass of microbial organisms is an innovative and alternative technology for removal of these pollutants from aqueous solution. The search of marine actinobacteria with potential heavy metal biosorption ability resulted in the identification of a novel alkalophilic Streptomyces VITSVK5 species. The biosorption property of Streptomyces VITSVK5 spp. was investigated by absorbing heavy metals Cadmium (Cd) and Lead (Pb). Physiochemical characteristics and trace metal concentration analysis of the backwater showed the concentrations of different metals were lead 13±2.1 μg L⁻¹, cadmium 3.1±0.3μg L⁻¹, zinc 8.4±2.6μg L⁻¹ and copper 0.3±0.1μg L⁻¹, whereas mercury was well below the detection limit. The effect of pH and biomass dosage on removal efficiency of heavy metal ions was also investigated. The optimum pH for maximal biosorption was 4.0 for Cd (II) and 5.0 for Pb (II) with 41% and 84% biosorption respectively. The biosorbent dosage was optimized as 3 g L-1 for both the trace metals. Fourier transform infrared absorption spectrum results indicated the chemical interactions of hydrogen atoms in carboxyl (-COOH), hydroxyl (-CHOH) and amine (-NH₂) groups of biomass with the metal ions. This could be mainly involved in the biosorption of Cd (II) and Pb (II) onto Streptomyces VITSVK5 spp. The results of our study revealed Streptomyces metabolites could be used to develop a biosorbent for adsorbing metal ions from aqueous environments.     

Effect of barley straw biochar application on greenhouse gas emissions from upland soil for Chinese cabbage cultivation in short-term laboratory experiments

Chinese cabbage was cultivated in upland soil with the addition of biochar in order to investigate the potential for reduction of greenhouse gas emissions. Barley straw biochar (BSB) was introduced in a Wagner pot (1/5000a) in amounts of 0 (BSB0, control), 100 (BSB100), 300 (BSB300), and 500 (BSB500) kg 10a^-1. After the addition of BSB into the upland soil, carbon dioxide (CO₂) emission increased while methane (CH₄) and nitrous oxide (N₂O) emissions decreased. The highest CO₂ flux was measured for the BSB500 sample, (84.6 g m^-2) followed by BSB300, BSB100, and BSB0 in decreasing order. Relative to those of control, the total CH₄ flux and N₂O flux for the BSB500 treatment were lower by 31.6% and 26.1%, respectively. The global warming potential (GWP) of the treatment without biochar was 281.4 g CO₂ m^-2 and those for treatments with biochar were in the range from 194.1 to 224.9 g CO₂ m^-2. Therefore, introducing BSB into upland soil to cultivate Chinese cabbages can reduce the global warming potential.     

ESTIMATE OF METHANE EMISSIONS FROM RICE FIELDS IN CHINA BY CLIMATE-BASED NET PRIMARY PRODUCTIVITY

1INTRODUCTIONIrrigated ricefieldsarecharacterizedbylargespatialandtemporalvariationsin CH4 emissiontotheatmo-sphere.Accordingly,thereisagreatuncertaintyintheestimate ofCH4 emissionsfromricefields.GreateffortshavebeenmadetoestimatetheCH4 emissionsfromricefieldsandseveralapproacheshavebeendeveloped.TherepresentativemethodsincludetheIPCC(Inter-governmentPanelofClimateChange)region-specificemissionfactormethodandthemodelcalculationmethod.Toimprovethecalculationaccuracy,theIPCCmethodreq…     

Studies on the community structures of meiofauna and marine nematode at six stations in the Southern Yellow Sea,China

1Introduction As part of a comprehensive investigation of ecosys-tem dynamics in the Yellow Sea and East China Sea,astudy has been made of meiofauna,defined here asmetazoans passing a0.5mm sieve but retained by a0.031mm sieve.Meiofauna is an important energeticgroup in benthic small food web due to their smallsize,high abundance and fast turnover rates.Theproduction of meiofauna is equal to or higher than thatof macrofauna in estuaries,shallow waters and deepseas(Gerlach,1971;Platt and Warw…