Comparative study of two models to simulate diffuse nitrogen and phosphorus pollution in a medium-sized watershed, southeast China

The aim of this study was to compare and assess two models to calculate diffuse nitrogen and phosphorus emissions in a selected watershed. The GIS-based empirical model and the physically-based AnnAGNPS model were evaluated for comparative purposes. The methodologies were applied for the Jiulong River watershed, covering 14,700 km(2) located in southeast China, with intensive agricultural activities. The calculated loadings by AnnAGNPS model was checked by the measured values at the watershed outlet, whereas the calculated nitrogen and phosphorus emission by GIS-based empirical model spatially provided the potential values in terms of sub-watersheds, districts/counties, and land use type. Both models gave similar levels of diffuse total nitrogen emissions, which also fit well with previous estimates made in the Jiulong River watershed. Comparatively, the GIS-based empirical model gave sound results of source apportionment of non-point source pollution (NPS) froth the available input data and critical source areas identification of diffuse nitrogen and phosphorus pollution. The AnnAGNPS model predicted reasonable nitrogen loading at the watershed outlet and simulated well for NPS management alternatives under changing land use conditions. The study indicated that the GIS-based empirical model has its advantage in extensive studies as a decisions support tool for preliminary design since it is easily applied to large watersheds with fewer data requirements, while AnnAGNPS has its advantage in detailed emission assessment and scenario development. (C) 2009 Elsevier Ltd. All rights reserved

Preliminary study on PAH degradation by bacteria from contaminated sediments in Xiamen Western Sea, Fujian, China

In order to estimate the biodegradation of three polycyclic aromatic hydrocarbons (PAHs) compounds, bacterial strains were isolated from marine sediments in three heavily contaminated sites (Yuandang Lake, Dongdu Port and Aquacultural zones in Maluan Bay) in Xiamen Western Sea. The results show three bacterial strains, which used pyrene as the sole carbon source, were identified as strains of Aureobacterium sp., Arthrobacter sp., Rhodococcus sp. The PAH-degrading bacteria isolated had a strong ability to degrade phenanhrene,fluoranthene and pyrene at different degradation rates. The highest degradation rate was observed when three PAH compounds were mixed with an individual strain in the medium. The three PAHs were degraded after one week with a degradation rate of 89.94% for phenanthrene and 93.4 % for both of fluoranthene and pyrene.In addition, after 25 days of incubation, the degradation rate was 99.98 % for phenanthrene and 99.97 % for both of fluoranthene and pyrene. Optical density was measured to estimate bacterial growth during the degradation of PAHs. Highest levels of bacterial growth were observed with a three PAH mixture in the culture, suggesting that the concentration of PAHs influenced bacterial growth and the highest levels of degradation for most series were detected after one week of incubation.Supported by the NSFC (No.30070157, 40206015), and the Scientific Fund of Quanzhou City (No. Z200234)

Treatment of was tewater from jeans production by hydrolytic acidification /biological contact oxidation /sedimentation

[摘要]：针对牛仔衣染色( 以靛蓝染料为主) 废水色度较高、有毒性及污染严重的特点, 确定采用水解酸化/生物 接触氧化/沉淀的工艺处理该废水。在丽发制衣厂的应用实践表明: 该工艺切实可行, 运行费用低, 处理效果稳定, 出 水水质达到DB 44 /26—2001 中一级排放标准, COD、BOD5、SS、色度去除率分别达到94%、92%、87%、83%。[Abstract]:The wastewater fromjeans production(mainly containing indigo dyeing) is characterized by higher colourity, toxicity and severe pollutant. With the consideration of these special characters, the wastewater is treated by hydrolysis acidification /biological contact oxidation /sedimentation process. The operation in Lifa Clothing Manufacture demonstrates that this process is feasible. Its running cost is low and the treatment results are stable. Finally, it also shows that the treated effluent quality accords with the requirement of Ⅰclass standard of water pollutant discharge extreme(DB 44 /26—2001) in Guangdong province. Its COD, BOD5, SS and colourity removal rate reach 94%, 92%, 87% and 83% respectively.海南省自然科学基金资助项目( 80673

The distribution characteristics of bacterial β-glucosidase activity in Taiwan strait

Twenty stations were established in the near-shore regions of South Fujian Shoal (116°10’-119°00’E,21°20’-24°10’N) on summer and winter cruises during the period from August 1997 and February to March 1998. The distribution pattern of marine bacterial β-glucosidase activity (β-GlcA) has been investigated by using fluorogenic model substrate (FMS) technique in order to have better understanding of the β-GlcA, as well as its relation to marine bacterial biomass, productivity and environmental factors in Taiwan strait. The results showed that: (1) In summer, the average of β-GlcA at the Southern stations of Taiwan strait was 1.94 nmol/1 h. While in winter, the average of β-GlcA at the Northern stations was 0.86 nmol/1 h and the range of variation (0.34–1.89 nmol/1 h) was much more narrow than that in summer (0.31–8.1 nmol/1 h). (2) According to the carbon conversion factor, the β-GlcA was 0.14 and 0.062 ugc/1 h in summer and winter respectively. These β-GlcA values were higher than the bacterial production of the two seasons respectively. (3) The β-GlcA gradually rises from offshore water to near-shore water. (4) The correlation between the β-GlcA and the bacterial secondary production was not so obvious. (5) The correlation between the section distributions, daily varying of the β-GlcA and the bacterial production was not obvious. (6) In the surface water, the distribution character of free-state β-GlcA from bacteria was equal to that of the total β-GlcA in the whole sea area

Protein profiles in zebrafish (Danio rerio) brains exposed to chronic microcystin-LR

Microcystin-LR (MCLR) is a commonly encountered blue-green algal hepatotoxin and a known inhibitor of cellular protein phosphatase (PP), however, little is known about its neurotoxicity. This study investigated the protein profiles of zebrafish (Danio rerio) brains chronically exposed to MCLR concentrations (2 or 20 mu g L-1) using the proteomic approach. The results showed that MCLR strikingly enhanced toxin accumulation and the PP activity in zebrafish brains after 30 d exposure. Comparison of two-dimensional electrophoresis protein profiles of MCLR exposed and non-exposed zebrafish brains revealed that the abundance of 30 protein spots was remarkably altered in response to MCLR exposure. These proteins are involved in cytoskeleton assembly, macromolecule metabolism, oxidative stress, signal transduction, and other functions (e.g. transporting, protein degradation, apoptosis and translation), indicating that MCLR toxicity in the fish brain is complex and diverse. The chronic neurotoxicity of MCLR might initiate the PP pathway via an upregulation of PP2C in the zebrafish brain, in addition to the reactive oxygen species pathway. Additionally, the increase of vitellogenin abundance in MCLR exposed zebrafish brains suggested that MCLR might mimic the effects of endocrine disrupting chemicals. This study demonstrated that MCLR causes neurotoxicity in zebrafish at the proteomic level, which provides a new insight into MCLR toxicity in aquatic organisms and human beings. (c) 2010 Elsevier Ltd. All rights reserved.National Natural Science Foundation of China [40806051]; State Key Laboratory of Marine Environmental Science ; Program for New Century Excellent Talents in Universit

P relim inary resu lts concern ing th e spa tio2tempora l pa ttern and mechan ism of n itrogen sources and expor ts in th e J iu long R iver wa tersh ed

[摘要]：综合运用定位监测、野外试验、模型模拟与G IS技术等手段和方法, 定量研究了南亚热带地区九龙江流域和五川小流域氮的大气沉降、河 流输送(地表径流)、淋失、反硝化和氨挥发等输入输出(源汇)时空模式与机理. 结果表明, 九龙江流域氮/ 源0以化肥与饲料输入为主(占总输 入125. 6kg# hm- 2的86% ), 氮/ 汇0以氨挥发和河流输送为主(占总输出72. 9kg# hm- 2的82% ). 氮输入后50%以上进入大气和水环境, 14. 5% 通过河流输送至河口与近海. 大气氮沉降通量为14. 9kg# hm- 2, 其中干沉降占34%, 湿沉降占66%, 形成1B2 的干湿沉降结构;源于化肥施用与 畜禽养殖引起的强烈氨挥发, 氮沉降集中在春夏两季(占全年80% ), 且以铵态氮为主( 39%以上). 氮的径流输出及河流输送受人为氮输入与 水文条件的双重控制, 2004年九龙江向厦门海域输送无机氮11. 5kg# hm- 2, 其中90%发生在春夏秋季(同期流量占全年89% ); 五川小流域总 氮径流输出负荷为67. 1kg# hm- 2, 其中85%发生在施肥量大、降雨集中的春夏两季(作物生长期); 基流与降雨径流分别贡献25%和75%. 总 氮淋失负荷为27. 5kg# hm- 2, 占总输入的9%; pH < 5的酸性土壤带正电荷导致氮淋失以铵态氮为主(约占40% ). 九龙江流域反硝化通量为 71 7 kg# hm- 2, 而氨挥发高达42. 1kg# hm- 2, 氨挥发主要来自化肥施用与畜禽养殖(分别贡献50% 和39% ). 减少春夏时期肥料氮的输入(养分 管理), 有效截留雨季的降雨径流(水文控制)是该流域氮素管理的关键.国家自然科学基金国际(地区)合作交流项目( No. 40810069004); 福建省/ 十五0重大科技资助项目(N o. 2002H 009

A sulfotransferase specific to N-21 of gonyautoxin 2/3 from crude enzyme extraction of toxic dinoflagellate Alexandrium tamarense CI01

[Abstract]:Sulfotransferase (ST) is the first enzyme discovered in association with paralytic shellfish poisoning (PSP) toxin biosynthesis in toxic dinoflagellates. This study investigates the ST activity in crude enzyme extraction of a toxic dinoflagellate species, Alexandrium tamarense CI01. The results show that crude enzyme can transfer a sulfate group from 3’-phosphoadenosine 5’-phosphosulfate (PAPS) to N-21 in the carbamoyl group of gonyautoxin 2/3 (GTX2/3) to produce C1/C2, but is inactive toward STX to produce GTX5. The crude enzyme is optimally active at pH 6.0 and 15°C. The activity is enhanced by Co2+, Mg2+, Mn2+ and Ca2+ individually, but is inhibited by Cu2+. Moreover, the activity shows no difference when various sulfur compounds are used as sulfate donors. These results demonstrate that the ST specific to GTX2/3 is present in the cells of A. tamarense CI01 and is involved in PSP toxin biosynthesis. In addition, the ST from different dinoflagellates is species-specific, which explains well the various biosynthesis pathways of the PSP toxins in toxic dinoflagellates.Supported by the National Natural Science Foundation of China (No.40376032) and the Ministry of Science and Technology of the People’s Republic of China (No.2001CB409700)

Optimization of crude enzyme preparation methods for analysis of glutamine synthetase activity in phytoplankton and field samples

Glutamine synthetase (GS) is an important enzyme involved in nitrogen assimilation and metabolism in marine phytoplankton. However, little work has been done in situ due to the limitation of crude enzyme preparation methods. In this study, three enzyme preparation methods, high-speed centrifugation (HC, <10 000 g), ultracentrifugation (UC, 70 000 g), and ultrafiltration (UF) with 100 k mu molecular weight cutoff, were compared using two diatom species (Asterionellopsis glacialis and Thalassiosira weissflogii), and two dinoflagellate species (Alexandrium catenella and Prorocentrum donghaiense) as experimental materials together with field samples collected from Xiamen Harbor, China. The results showed that HC is the best method to prepare crude enzymes for glutamine synthetase activity (GSA) in diatom species and diatom-dominant samples, while UF is the best method to extract GS from dinoflagellate species and dinoflagellate-dominant samples. For the HC method, the optimal centrifugal speed and time were 10 000 g and 35 min, respectively, and under these conditions, the highest GSA was obtained in all samples. This study indicates that both methods (HC and UF) overcome the limitation of centrifugal speed and could be applied to in situ GSA analysis, especially at sea.The National Natural Science Foundation of China [40331004]; Ministry of Science and Technology of China [2005DFA20430